Filed pursuant to Rule 424(b)(3)
                                                    Registration No. 333-117925

                                    PROSPECTUS

                                   [EPIX LOGO]

    $100,000,000 PRINCIPAL AMOUNT OF 3.00% CONVERTIBLE SENIOR NOTES DUE 2024

                                   ----------


                        3,359,086 SHARES OF COMMON STOCK
                      ISSUABLE UPON CONVERSION OF THE NOTES

                                   ----------


                               EPIX PHARMACEUTICALS, INC.

                                   ----------

         We issued $100,000,000 aggregate principal amount of our 3.00%
Convertible Senior Notes due 2024 in a private placement on June 7, 2004. The
initial purchasers resold the notes to qualified institutional buyers in
accordance with Rule 144A under the Securities Act of 1933, as amended. This
prospectus will be used by the selling security holders from time to time to
resell their notes and the common stock issuable upon the conversion of the
notes. We will not receive any proceeds from the sale of the notes or the shares
of common stock issuable upon the conversion of the notes.

         The notes bear interest at the rate of 3.00% per annum, from December
15, 2004, payable semi-annually in arrears on June 15 and December 15 of each
year, beginning December 15, 2004.

         The notes will mature on June 15, 2024. We may redeem some or all of
the notes at any time after June 15, 2009 at the redemption prices specified in
this prospectus plus accrued and unpaid interest and additional interest, if
any, to, but excluding, the date of redemption.

         Holders of the notes have the right to require us to repurchase the
notes at a purchase price equal to 100% of the principal amount of the notes
plus accrued and unpaid interest, if any, on June 15, 2011, 2014 and 2019 or
upon a termination of trading or a change of control event, each as described in
this prospectus.

         Holders of the notes may convert the notes into shares of our common
stock only in the following circumstances:

         -    if the price of our common stock reaches a specified threshold
              over a specified period as described in this prospectus;
         -    if the notes are called for redemption;
         -    if we make specified distributions on our common stock or engage
              in specified corporate transactions; and
         -    at any time before June 15, 2019 if the trading price of the notes
              falls below certain thresholds.

         The initial conversion price is $29.77 per share (equivalent to an
initial conversion rate of approximately 33.5909 shares per $1,000 principal
amount of the notes), subject to adjustment in certain circumstances. Our common
stock is traded on the Nasdaq National Market under the symbol "EPIX." The last
reported closing price of our common stock on November 4, 2004 was $16.03 per
share.

         The notes are unsecured and will rank equally with all existing and
future unsecured senior indebtedness except that the notes are subordinated to
certain senior indebtedness described in this prospectus. The notes will rank
senior in right of payment to all existing and future unsecured subordinated
debt.

         For a more detailed description of the notes, see the "Description of
Notes" beginning on page 18.



                                   ----------

         Our address is EPIX Pharmaceuticals, Inc., 161 First Street, 
Cambridge, Massachusetts, and our telephone number is (617) 250-6000.

INVESTING IN THE NOTES OR OUR COMMON STOCK INVOLVES A HIGH DEGREE OF RISK. SEE
"RISK FACTORS" BEGINNING ON PAGE 6.

                                   ----------

NEITHER THE SECURITIES AND EXCHANGE COMMISSION NOR ANY STATE SECURITIES
COMMISSION HAS APPROVED OR DISAPPROVED OF THESE SECURITIES, OR DETERMINED IF
THIS PROSPECTUS IS TRUTHFUL OR COMPLETE. ANY REPRESENTATION TO THE CONTRARY IS A
CRIMINAL OFFENSE.

                                   ----------


                  The date of this prospectus is November 5, 2004




================================================================================

                                TABLE OF CONTENTS




                                                          PAGE
                                                        
Prospectus Summary.................................         1
Risk Factors.......................................         6
Forward-Looking Statements.........................        24
Ratio of Earnings to Fixed Charges.................        24
Use of Proceeds....................................        24
Description of Notes...............................        25
Description of Capital Stock.......................        40
Certain U.S. Federal Income Tax Consequences.......        41
Selling Holders....................................        48
Plan of Distribution...............................        50
Legal Matters......................................        51
Experts............................................        51
Where You Can Find More Information................        51
Incorporation of Documents By Reference............        51


================================================================================


You should rely only on the information provided or incorporated by reference in
this prospectus or any prospectus supplement. Neither we nor the selling holders
have authorized anyone to provide you with additional or different information.
The selling holders are not making an offer of these securities in any
jurisdiction where the offer is not permitted. You should assume that the
information in this prospectus and any prospectus supplement is accurate only as
of the date on the front of the document and that information incorporated by
reference in this prospectus or any prospectus supplement is accurate only as of
the date of the document incorporated by reference. In this prospectus and any
prospectus supplement, unless otherwise indicated, "we," "us" and "our" refer to
EPIX Pharmaceuticals, Inc., and do not refer to the selling holders.

"EPIX," "EPIX Pharmaceuticals" and the "EPIX" logo are trademarks and 
registered trademarks of EPIX Pharmaceuticals, Inc. All other trademarks 
appearing in this prospectus are the property of their holders. In September 
2004, we changed our name from EPIX Medical, Inc. to EPIX Pharmaceuticals, 
Inc.



                               PROSPECTUS SUMMARY

     THIS SUMMARY HIGHLIGHTS INFORMATION ABOUT EPIX PHARMACEUTICALS, INC. 
BECAUSE THIS IS A SUMMARY, IT MAY NOT CONTAIN ALL THE INFORMATION YOU SHOULD 
CONSIDER BEFORE INVESTING IN THE NOTES OR THE COMMON STOCK ISSUABLE UPON 
THEIR CONVERSION. YOU SHOULD READ THIS ENTIRE PROSPECTUS CAREFULLY.

                           EPIX PHARMACEUTICALS, INC.

     We are a leading developer of targeted contrast agents, designed to 
improve the diagnostic quality of images produced by magnetic resonance 
imaging, or MRI. MRI has been established as the imaging technology of choice 
for a broad range of applications, including the identification and diagnosis 
of a variety of medical disorders. MRI is safe, relatively cost-effective and 
provides three-dimensional images that enable physicians to diagnose and 
manage disease in a minimally invasive manner. We are currently developing 
two products for use in MRI to improve the diagnosis of multiple 
cardiovascular diseases affecting the body's arteries and veins, collectively 
known as the vascular system. In December 2003, we submitted a New Drug 
Application, or NDA, for MS-325, our principal product under development, to 
the U. S. Food and Drug Administration, or FDA. In February 2004, we were 
notified by the FDA that the NDA for MS-325 had been accepted for filing and 
had been designated for a standard review cycle. In October 2004, we were 
notified by the FDA that it had extended the action date for completion of 
its review of MS-325 by 90 days to January 2005 and we are in discussions 
with the FDA about open review issues. If our NDA for MS-325 is approved by 
the FDA, our partner, Schering AG, will have primary responsibility for the 
product launch and marketing of MS-325. In June 2004, Schering AG submitted 
MS-325 for marketing approval in the European Union.

                             OUR PRODUCT CANDIDATES

     MS-325. Our principal product under development, MS-325, is designed to
provide visual imaging of the vascular system, through a type of MRI known as
magnetic resonance angiography, or MRA. We believe that MS-325-enhanced MRA has
the potential to improve the diagnosis of multiple diseases of the vascular
system, including vascular disease outside the heart, known as peripheral
vascular disease, and diseases that affect the coronary arteries and reduce
blood flow to the heart. Our initial target indication for MS-325 is for use in
MRA imaging of peripheral vascular disease. We are also developing MS-325 for
imaging the coronary arteries and the heart and initiated Phase II cardiac
studies in July 2004.

     We believe that MS-325 will significantly enhance the quality of MRI and 
provide physicians with a minimally-invasive and cost-effective method for 
diagnosing vascular disease. We also believe that MS-325-enhanced MRA has the 
potential to simplify the diagnosis of vascular disease and to replace a 
significant portion of X-ray angiographic procedures, a highly invasive and 
expensive catheter-based method most frequently used for the detection of 
vascular disease. In 2003, approximately 8.5 million angiographic procedures 
were performed in the U.S. for the diagnosis of diseases of the vascular 
system, of which 4.6 million procedures were by way of X-ray angiography. We 
believe that MS-325-enhanced MRA will be a less invasive method of imaging a 
patient's vascular anatomy for the evaluation of disease.

     CLINICAL TRIAL RESULTS AND NDA. We have submitted an NDA for MS-325 
based on a 780-patient Phase III clinical trial program designed to test the 
safety and efficacy of MS-325 for the imaging of peripheral vascular disease. 
We conducted four Phase III trials to determine the efficacy of 
MS-325-enhanced MRA for the detection of vascular disease in the lower 
abdomen and pelvic regions, in the renal arteries of the kidneys and in the 
pedal arteries of the feet. All four trials in the Phase III program for 
MS-325 met their primary endpoints. In communications with the FDA in October 
2004, the FDA indicated that its principal open review questions relate to 
the non-contrast MRA comparator scans used in the Phase III trials and to the 
statistical treatment of uninterpretable scans. We have subsequently provided 
detailed responses to the FDA's questions. Although we remain confident in 
the safety and efficacy profile of MS-325, the FDA's review of the additional 
analyses and interpretations we have provided could adversely affect the 
approval, timeliness of approval or labeling of MS-325.

     MRI IN THE DIAGNOSIS OF VASCULAR DISEASE. The use of MRI has grown steadily
over the past 10 years due to reduced cost and improved imaging capabilities.
MRI provides an effective method for diagnosing a broad range of diseases. MRI
manufacturers have improved both the hardware and software used in their
systems, reducing the procedure time and significantly enhancing image
resolution. While MRI is currently used extensively to image many organs and
tissues in the body, its use in imaging the vascular system has been limited.
Currently available MRI contrast agents for MRA are not optimal for the
diagnosis of vascular disease in many vascular beds due to the rapid leakage of
the injectable contrast agent from the vascular system into the surrounding
tissue, usually within 30 to 60 seconds. As a result of this leakage, the time
available to image blood vessels with these contrast agents is too short to
obtain the high resolution images necessary for broad clinical application. In
addition, performance of MRA using currently approved contrast agents generally
requires specialized equipment and specially trained staff. None of the
currently available MRI contrast agents

                                        1


is approved by the FDA for use in MRA. In 2003, approximately 2.7 million MRAs
were performed in the U.S., an increase of 22% over 2002.

     MS-325-ENHANCED MRA. MS-325 is specifically designed to enhance the quality
of magnetic resonance images of the arteries and veins and to provide physicians
with a superior method for diagnosing vascular disease. MS-325 is a small
molecule, which produces an MRI signal because of the presence of gadolinium, a
magnetically active element favored by clinicians for enhancing magnetic
resonance images. MS-325 is designed with our proprietary technology to bind
reversibly to albumin, the most common protein in the blood. Using standard MRI
techniques, MS-325-enhanced MRA produces a strong magnetic signal, resulting in
bright images of the blood against the dark background of surrounding tissue.
Because of its affinity for albumin, MS-325 remains at high concentrations in
the bloodstream throughout the MRI exam, providing the extended, approximately
60-minute image time and signal strength required to obtain a high resolution
image of multiple regions of the vascular system. Like most currently available
general use MRI contrast agents, MS-325 is designed to be safely eliminated from
the body through the kidneys over time. In addition, in clinical studies of
renally-compromised patients, MS-325 appeared safe and well tolerated, a
potentially important feature given the renal risks of X-ray angiography.

     EP-2104R. We are developing a second targeted contrast agent, EP-2104R,
which is designed to illuminate and identify blood clots using MRI. Finding
blood clots is of critical medical significance in the evaluation and diagnosis
of patients with stroke, chest pain, heart attack, irregular heartbeat and clots
in the lungs and legs. We designed EP-2104R to bind reversibly to fibrin, the
dominant protein found in clots. In pre-clinical studies, EP-2104R has been
shown to enhance the ability of MRI to image clots. We announced the 
initiation of human clinical studies for EP-2104R in August 2004.

                          OUR STRATEGIC COLLABORATIONS

     We have established collaborations with large pharmaceutical companies to
enhance our internal development capabilities and to offset a substantial
portion of the financial risk of developing our product candidates. At the same
time, we maintain substantial rights to product candidates covered by these
collaborations, which provide us the opportunity to participate in a significant
portion of the potential economic benefit from their successful development and
commercialization. Our most significant collaborations involve Schering AG for
the development and commercialization of MS-325, EP-2104R and for the discovery
of other MRI contrast agents. We have also formed collaborations with the three
leading MRI scanner manufacturers, GE Medical Systems (now GE Healthcare),
Philips Medical Systems and Siemens Medical Systems, to develop advanced imaging
techniques and tools designed to facilitate the use of MS-325-enhanced MRA.

                                  OUR STRATEGY

     Our objective is to become a worldwide leader in MRI contrast agents by
developing and commercializing products using our proprietary technology
platform. We intend to pursue this strategy through internal product development
efforts, collaborations with strategic partners and by acquiring the rights to
complementary technologies. We also intend to expand the potential applications
for our current product candidates. We believe we can build on our leadership in
developing targeted contrast agents for MRI through further research and
development programs in cardiovascular imaging and therapeutics. In addition, we
intend to consider other opportunities to expand beyond MRI.

                              CORPORATE INFORMATION

     We incorporated in Delaware in 1988 and commenced operations in 1992. 
Our principal executive offices are located at 161 First Street, Cambridge, 
Massachusetts 02142-1118 and our telephone number is (617) 250-6000. Our 
website is located at http://www.epixpharma.com. Our Corporate Code of 
Conduct and Ethics as well as our annual reports on Form 10-K, quarterly 
reports on Form 10-Q and current reports on Form 8-K and all amendments to 
these reports, which have been filed with the SEC, are available to you free 
of charge through the Investor Relations section on our website as soon as 
reasonably practicable after such materials have been electronically filed 
with, or furnished to, the SEC. We do not intend for the other information 
contained in our website to be considered a part of this prospectus.

                                        2


                                  THE OFFERING


                                
Issuer.........................    EPIX Pharmaceuticals, Inc.

Notes Offered..................    $100,000,000 aggregate principal amount of 3.00% Convertible Senior Notes due 2024.

Issue Price....................    The notes have been issued at a price of 100% of their principal amount, which is
                                   $1,000 per note, plus accrued interest, if any, from December 15, 2004.

Maturity Date..................    June 15, 2024

Ranking......................      The notes will:

                                   -   be our senior unsecured obligations;

                                   -   be subordinated in right of payment to up to $15,000,000 plus accrued and unpaid
                                       interest on existing and future indebtedness under our Loan Agreement, dated May
                                       26, 2003, as amended, with Schering AG, referred to as our Schering AG loan
                                       facility;

                                   -   rank on parity in right of payment with all of our existing and future senior
                                       debt other than our Schering AG loan facility; and

                                   -   rank senior in right of payment to all of our future debt that is subordinated to
                                       the notes.

                                   The notes also are effectively subordinated in right of payment to our existing and
                                   future secured debt, to the extent of such security, and will be effectively
                                   subordinated in right of payment to any liabilities of any subsidiary that we may
                                   create in the future.

Interest.......................    The notes will bear interest at 3.00% per annum on the principal amount of the notes,
                                   payable semi-annually in arrears on June 15 and December 15 of each year, beginning
                                   December 15, 2004.

Conversion Rights..............    You may convert the notes into shares of our common stock at a conversion rate of
                                   33.5909 shares per $1,000 principal amount of notes (which represents an initial
                                   conversion price of $29.77 per share), subject to adjustment, prior to the close of
                                   business on the final maturity date under any of the following circumstances:

                                   -   during any fiscal quarter prior to June 15, 2019, if the closing sale price of
                                       our common stock for at least 20 trading days in the period of 30 consecutive
                                       trading days ending on the eleventh trading day of any fiscal quarter is more
                                       than 120% of the conversion price in effect on such eleventh trading day
                                       (initially 120% of $29.77, or $35.72);

                                   -   if the notes are called for redemption;

                                   -   if we make specified distributions on our common stock or engage in specified
                                       corporate transactions; or


                                        3



                                
                                   -   during the five trading day period immediately following any five consecutive
                                       trading day period in which the average trading price per $1,000 principal amount
                                       of the notes for such five day period is less than 98% of the product of the
                                       closing sale price of our common stock on a given day multiplied by the number of
                                       shares of common stock into which each $1,000 principal amount of the notes is
                                       convertible.

                                   See "Description of Notes - Conversion of Notes."

Redemption.....................    On or after June 15, 2009, we may redeem the notes, in whole or in part, at the
                                   following percentages of the principal amount of the notes, plus accrued and unpaid
                                   interest and additional interest, if any, to, but excluding, the redemption date:


                                                DATE                                 REDEMPTION PRICE
                                                ----                                 ----------------
                                                                                      
                                   June 15, 2009 to June 14, 2010..................      100.857%
                                   June 15, 2010 to June 14, 2011..................      100.429%
                                   June 15, 2011 and thereafter....................      100.000%


                                
                                   We will give you at least 20 days' notice of any such redemption. If we redeem the
                                   notes in whole or in part, other than a redemption of less than $7.5 million in
                                   cumulative principal amount of the notes, then we will be required to repay the then
                                   outstanding principal amount, together with accrued and unpaid interest, under our
                                   Schering AG loan facility.

Repurchase at the Option of
    the Holder.................    You may require us to repurchase the notes, in whole or in part, on June 15, 2011,
                                   2014 and 2019 for a repurchase price equal to 100% of the principal amount of the
                                   notes plus accrued and unpaid interest and additional interest, if any, to, but
                                   excluding, the date of redemption. Before we repurchase the notes in whole or in
                                   part, we will be required to repay the then outstanding principal amount, together
                                   with accrued and unpaid interest, under our Schering AG loan facility.

Sinking Fund...................    None.

Repurchase at the Option of
     the Holder Upon a
     Designated Event..........    Upon a change in control or a termination of trading (each as defined under
                                   "Description of Notes--Repurchase at the Option of the Holder Upon a Designated
                                   Event"), each holder of the notes may require us to repurchase some or all of its
                                   notes at 100% of the principal amount of the note, plus accrued and unpaid interest
                                   and additional interest, if any, to, but excluding, the date of redemption. Upon a
                                   change in control we may, at our option, elect to pay the repurchase price in cash,
                                   shares of our common stock valued at a discount of 5% from the market price of our
                                   common stock, or any combination thereof, subject to our satisfaction of the
                                   conditions set forth in "Description of Notes--Repurchase at the Option of the Holder
                                   Upon a Designated Event." Upon a termination of trading we will pay the repurchase
                                   price in cash. Before we repurchase the notes in whole or in part for cash, we will
                                   be required to repay the then outstanding principal amount, together with accrued and
                                   unpaid interest, under our Schering AG loan facility.

Registration Rights............    We have agreed to use our reasonable best efforts to keep a shelf registration
                                   statement with respect to the resale of the notes and shares of common stock


                                        4



                                
                                   issuable upon conversion of the notes effective during the periods specified in
                                   "Description of Notes - Registration Rights."

Additional Interest............    If the prospectus included in the shelf registration statement is suspended for more
                                   than 30 days in any three-month period or more than 90 days in any 12-month period,
                                   additional interest will accrue equal to 0.25% per annum for the first 90 days from
                                   and including the date on which the registration default has occurred, and 0.50% per
                                   annum as additional interest on the notes from and including the 91st day after the
                                   registration default, to, but excluding, the date on which the registration default
                                   is cured. Additional interest will be paid semi-annually in arrears.

DTC Eligibility................    The notes have been issued in book-entry form and will be represented by one or more
                                   permanent global certificates deposited with a custodian for and registered in the
                                   name of a nominee of the Depository Trust Company, or DTC, in New York, New York.
                                   Beneficial interests in the notes will be shown on, and transfers will be effected
                                   only through, records maintained by DTC and its direct and indirect participants. Any
                                   such interest may not be exchanged for certificated securities, except in limited
                                   circumstances. See "Description of Notes - Global Note, Book-Entry Form."

Trading  ......................    The notes are not listed on any national securities exchange. The notes are eligible
                                   for trading on The PORTAL(SM) Market; however, we provide no assurance as to the
                                   liquidity of, or trading markets for, the notes.

Absence of a Public Market.....    There is currently no public market for the notes. An active or liquid market may not
                                   develop for the notes.

Nasdaq National Market Symbol
     Of our Common Stock.......    "EPIX."


                                        5


                                   RISK FACTORS

     AN INVESTMENT IN OUR COMMON STOCK INVOLVES A HIGH DEGREE OF RISK. YOU
SHOULD CAREFULLY CONSIDER THE FOLLOWING RISK FACTORS, AND OTHER INFORMATION IN
OUR PERIODIC REPORTS FILED WITH THE SEC. IF ANY OF THE FOLLOWING RISKS ACTUALLY
OCCUR, OUR BUSINESS, FINANCIAL CONDITION OR RESULTS OF OPERATIONS COULD BE
MATERIALLY AND ADVERSELY AFFECTED.

                            RISKS RELATED TO OUR BUSINESS

WE HAVE NEVER GENERATED REVENUES FROM COMMERCIAL SALES OF OUR PRODUCTS AND, IF
MS-325 DOES NOT RECEIVE APPROVAL FROM THE FOOD AND DRUG ADMINISTRATION (FDA), WE
WILL HAVE NO PRODUCTS TO MARKET IN THE FORESEEABLE FUTURE.

     We currently have no products for sale and we cannot guarantee that we will
ever have marketable products. MS-325 and EP2104R are currently our only product
candidates that have undergone human clinical trials and we cannot be certain
that any of our other development projects will yield a product candidate
suitable for substantial human clinical testing. As a result, our initial
revenues and profits from commercial sales of our products, if any, will be
derived from sales of MS-325. In October 2004, we were notified by the FDA that
it had extended the action date for completion of its review of the MS-325 NDA
by 90 days, to January 2005. In communications with the FDA in October 2004, 
the FDA indicated that its principal open review questions relate to the 
non-contrast MRA comparator scans used in the Phase III trials and to the 
statistical treatment of uninterpretable scans. We have subsequently provided 
detailed responses to the FDA's questions. Although we remain confident in 
the safety and efficacy profile of MS-325, the FDA's review of the additional 
analyses and interpretations we have provided could adversely affect the 
approval, timeliness of approval or labeling of MS-325. If MS-325 fails to 
achieve regulatory approval and market acceptance, and if we do not succeed 
in bringing any of our other product candidates to human clinical trials and 
achieve regulatory approval and market acceptance for them, our business will 
fail, and as a result, you may lose all or part of your investment.

     To date, we have received revenues from payments made under licensing,
royalty arrangements, and product development and marketing agreements with
strategic collaborators. In particular, our revenue for the nine months ended
September 30, 2004 was $10.1 million and consisted of $6.9 million from the
product development portion of our collaboration agreements with Schering AG for
MS-325, EP-2104R and MRI research, $2.7 million from a patent licensing and
royalty agreement with Bracco and $506,000 of license fee revenue related to the
strategic collaboration agreements for the development, manufacturing and
marketing of MS-325 with Schering AG and Tyco/Mallinckrodt. In addition to these
sources of revenue, we have financed our operations to date through public stock
offerings, private sales of equity securities, debt financing and equipment
lease financings.

     Although we are currently in compliance with the terms of our collaboration
agreements, the revenues derived from them are subject to fluctuation in timing
and amount. We may not receive anticipated revenue under our existing
collaboration or licensing agreements and, additionally, these agreements may be
terminated upon certain circumstances. Therefore, to achieve profitable and
sustainable operations, we, alone or with others, must successfully develop,
obtain regulatory approval for, introduce, market and sell products. We may not
receive revenue from the sale of any of our product candidates for the next
several years because we may not:

     -    successfully complete our product development efforts;

     -    obtain required regulatory approvals in a timely manner, if at all;

     -    manufacture our product candidates at an acceptable cost and with
          acceptable quality; or

     -    successfully market any approved products.

     As a result, we may never generate revenues from sales of our product
candidates and our failure to generate positive cash flow could cause our
business to fail.

WE ANTICIPATE FUTURE LOSSES AND MAY NEVER BECOME PROFITABLE.

                                        6


     Our future financial results are uncertain. We have experienced significant
losses since we commenced operations in 1992. Our accumulated net losses as of
September 30, 2004 were approximately $150.2 million. These losses have
primarily resulted from expenses associated with our research and development
activities, including pre-clinical and clinical trials, and general and
administrative expenses. We anticipate that our research and development
expenses will remain significant in the future and we expect to incur losses
over at least the next two years as we continue our research and development
efforts, pre-clinical testing and clinical trials and as we implement
manufacturing, marketing and sales programs. As a result, we cannot predict when
we will become profitable, if at all, and if we do, we may not remain profitable
for any substantial period of time. If we fail to achieve profitability within
the timeframe expected by investors, the market price of our common stock may
decline and consequently our business may not be sustainable.

IF THE MARKET DOES NOT ACCEPT OUR TECHNOLOGY AND PRODUCTS, WE MAY NOT GENERATE
SUFFICIENT REVENUES TO ACHIEVE OR MAINTAIN PROFITABILITY.

     The commercial success of MS-325 and our other product candidates, when and
if approved for marketing by the FDA and corresponding foreign agencies, depends
on their acceptance by the medical community and third party payors as
clinically useful, cost-effective and safe. While contrast agents are currently
used in an estimated 25% to 35% of all MRI exams, there are no MRI agents
approved by the FDA for vascular imaging. Furthermore, clinical use of MRA has
been limited and use of MRA for some vascular disease imaging has occurred
mainly in research and academic centers. Market acceptance, and thus sales of
our products, will depend on several factors, including:

     -    safety;

     -    cost-effectiveness relative to alternative vascular imaging methods;

     -    availability of third party reimbursement;

     -    ease of administration;

     -    clinical efficacy; and

     -    availability of competitive products.

     Market acceptance will also depend on our ability and that of our strategic
partners to educate the medical community and third party payors about the
benefits of diagnostic imaging with MRA enhanced with MS-325 compared to imaging
with other technologies. MS-325 represents a new approach to imaging the
non-coronary vascular system, and market acceptance both of MRA as an
appropriate imaging technique for the non-coronary vascular system, and of
MS-325, is critical to our success. If MS-325 or any of our other product
candidates, when and if commercialized, do not achieve market acceptance, we may
not generate sufficient revenues to achieve or maintain profitability.

WE MAY NEED TO RAISE ADDITIONAL FUNDS NECESSARY TO FUND OUR OPERATIONS, AND IF
WE DO NOT DO SO, WE MAY NOT BE ABLE TO IMPLEMENT OUR BUSINESS PLAN.

     Since inception, we have funded our operations primarily through our public
offerings of common stock, private sales of equity securities, debt financing,
equipment lease financings and product development revenue, royalty and license
payments from our strategic partners. Although we believe that we have adequate
funding for the foreseeable future, we may need to raise substantial additional
funds for research, development and other expenses, through equity or debt
financings, strategic alliances or otherwise. Our future liquidity and capital
requirements will depend upon numerous factors, including the following:

     -    the progress and scope of clinical trials;

     -    the timing and costs of filing future regulatory submissions;

                                        7


     -    the timing and costs required to receive both U.S. and foreign
          governmental approvals;

     -    the cost of filing, prosecuting, defending and enforcing patent claims
          and other intellectual property rights;

     -    the extent to which our products gain market acceptance;

     -    the timing and costs of product introductions;

     -    the extent of our ongoing and any new research and development
          programs;

     -    the costs of training physicians to become proficient with the use of
          our products; and

     -    the costs of developing marketing and distribution capabilities.

     Based on our current plans, expense rates, targeted timelines and our view
regarding acceptance of MS-325 in the marketplace, we estimate that cash, cash
equivalents and marketable securities on hand as of September 30, 2004 will be
sufficient to fund our operations until we turn cash flow positive. If we
consider other opportunities or change our planned activities, we may require
additional funding. As of September 30, 2004, we had outstanding the entire
$15.0 million loan facility available from Schering AG as part of our MRI
research collaboration. We repaid the $15.0 million loan, plus accrued interest,
in October 2004. We expect to redraw the $15.0 million loan as needed, but could
be unable to draw under the terms of the loan if we fail to meet certain
covenants or conditions precedent in the loan.

WE HAVE A LIMITED MANUFACTURING CAPABILITY AND WE INTEND TO RELY ON OUTSOURCED
MANUFACTURING TO PRODUCE MS-325.

     We do not have, nor do we currently have plans to develop, full-scale
manufacturing capability for MS-325. While we have manufactured small amounts of
MS-325 for research and development efforts, we rely on, and we intend to
continue to rely on, Tyco/Mallinckrodt as the primary manufacturer of MS-325 for
any future human clinical trials and commercial use. In the event that
Tyco/Mallinckrodt fails to fulfill its manufacturing responsibilities
satisfactorily, Schering AG has the right to purchase MS-325 from a third party
or to manufacture the compound itself. However, either course of action could
materially delay the manufacture and development of MS-325. Schering AG may not
be able to find an alternative manufacturer. In addition, Schering AG may not be
able to manufacture MS-325 itself in a timely manner. If we experience a delay
in manufacturing, it could result in a delay in the approval or
commercialization of MS-325 and have a material adverse effect on our business,
financial condition and results of operations.

IF MRI MANUFACTURERS ARE NOT ABLE TO ENHANCE THEIR HARDWARE AND SOFTWARE
SUFFICIENTLY, WE WILL NOT BE ABLE TO COMPLETE DEVELOPMENT OF OUR CONTRAST AGENT
FOR THE EVALUATION OF CARDIAC INDICATIONS.

     Although MRI hardware and software is sufficient for the evaluation of
non-coronary vascular disease, which is our primary target indication, we
believe that the technology is not as advanced for cardiac applications, which
will be our next clinical development target. Our initial NDA filing for MS-325
is related to non-coronary vascular disease. Imaging sequences on scanners
currently allow for the use of MS-325-enhanced MRA for diagnosing non-coronary
vascular disease, our lead indication. Based on feasibility studies we completed
in 2001, however, the imaging technology available for cardiac applications,
including coronary angiography and cardiac perfusion imaging, was not developed
to the point where there was clear visualization of the cardiac region, due to
the effects of motion from breathing and from the beating of the heart. We
recently initiated feasibility studies for cardiac indications using available
software and hardware that can be adapted for coronary and cardiac perfusion
data acquisition. We have entered into research collaborations with GE
Healthcare, Siemens Medical Systems and Philips Medical Systems that include
development and optimization of cardiac imaging sequences with contrast agents
like MS-325. We have also collaborated with a number of leading academic
institutions to help optimize cardiac imaging with MS-325. While

                                        8


significant progress has been made in developing these clinical applications for
cardiac imaging, we do not know when, or if, these techniques will enable MS-325
to provide clinically relevant images in cardiac indications. If MRI device
manufacturers are not able to enhance their scanners to perform clinically
useful cardiac imaging, we will not be able to complete our development
activities of MS-325 for that application, thereby reducing the potential market
for a product in this area.

OUR COMPETITORS MAY HAVE GREATER FINANCIAL RESOURCES, SUPERIOR PRODUCTS OR
PRODUCT CANDIDATES, MANUFACTURING CAPABILITIES AND/OR MARKETING EXPERTISE, AND
WE MAY NOT BE ABLE TO COMPETE WITH THEM SUCCESSFULLY.

     Medical technology is subject to intense competition and rapid
technological change. We have many competitors, including pharmaceutical,
biotechnology and chemical companies, a number of which, including our strategic
partners, are actively developing and marketing products that could compete with
our product candidates. Specifically, although there are no MRI contrast agents
that are FDA-approved for vascular imaging, there are a number of general use
MRI agents approved for other clinical applications in the U.S. and certain
foreign markets that are likely to compete with MS-325, if MS-325 is approved
for MRA. Collectively, these general use agents are referred to as
"extracellular" agents, and include: Magnevist(R) and Gadovist(R) by Schering
AG, Dotarem(R) by Guerbet, S.A., Omniscan(R) by Amersham Health, ProHance(R) and
MultiHance(R) by Bracco and OptiMark(R) by Tyco/Mallinckrodt. Extracellular
agents are broadly accepted in the market as general use MRI agents. None of
these agents is currently approved by the FDA for MRA, but their use in
applications outside of the primary indication described in the product labeling
is increasing and could present significant adoption hurdles for MS-325 if such
uses become entrenched in the marketplace. Additionally, we believe that some of
these general use agents are in clinical trials for an MRA indication. However,
these general use agents are not specifically designed for vascular imaging, and
because they "leak" out of the blood vessels into the extracellular space, they
do not provide the extended imaging window associated with MS-325. In addition,
we are aware of five agents that are under clinical development for use with
MRA: Schering AG's Gadomer-17 and SHU555C, Guerbet's Vistarem(R), Bracco's
B-22956/1 and Advanced Magnetics' Code 7228. Public information on the status of
clinical development and performance characteristics for these agents is
limited. However, many of these competitors have substantially greater capital
and other resources than we do and may represent significant competition for us.
These companies may succeed in developing technologies and products that are
more effective or less costly than any of those that we may develop. In
addition, these companies may be more successful than we are in developing,
manufacturing and marketing products.

     Moreover, there are several well-established medical imaging methods that
currently compete and will continue to compete with MRI, including Digital
Subtraction Angiography, or DSA, which is an improved form of X-ray angiography,
computed tomography angiography, or CTA, nuclear medicine and ultrasound, and
there are companies that are actively developing the capabilities of these
competing methods to enhance their effectiveness in cardiovascular system
imaging. DSA is currently considered the clinical gold standard for
cardiovascular angiography, but all methods offer advantages and disadvantages,
which are described in the following table:

                                        9




                         ADVANTAGES                                      DISADVANTAGES
                         ----------                                      -------------
                                                                   
MRI                      - Three-dimensional images                      - Requires high level of training
                         - Minimally-invasive                            - Inadvisable for patients with cardiac pacemakers
                         - Favorable safety profile                      - Less widely available
                         - High quality images

CT Angiography           - Rapid and easy data acquisition               - Radiation
                                                                         - Varying levels of toxicity
                                                                         - Calcium and bone artifacts
                                                                         - Time consuming post-processing

DSA                      - Significant clinical experience               - Invasive
(X-ray angiography)      - Opportunity to treat in same procedure        - Radiation
                         - Highest resolution                            - Varying levels of toxicity
                                                                         - Significant safety risks
                                                                         - Two-dimensional images
                                                                         - Expensive
                                                                         - Patient recuperation time

Ultrasound               - Low cost                                      - Operator dependent
                         - Fast                                          - Lack of anatomic detail
                         - Widely available                              - Bone precludes use in many vascular beds
                         - Non-invasive                                  - Inability to visualize small vessels


     We cannot guarantee that we will be able to compete successfully in the
future, or that developments by others will not render MS-325 or our future
product candidates obsolete or non-competitive, or that our collaborators or
customers will not choose to use competing technologies or products. Any
inability to compete successfully on our part will have a materially adverse
impact on our operating results.

WE CURRENTLY DEPEND ON OUR STRATEGIC COLLABORATORS FOR SUPPORT IN PRODUCT
DEVELOPMENT AND THE REGULATORY APPROVAL PROCESS, AND, IN THE FUTURE, WILL DEPEND
ON THEM FOR PRODUCT MARKETING SUPPORT AS WELL. THESE EFFORTS MAY SUFFER IF WE
EXPERIENCE PROBLEMS WITH OUR COLLABORATORS.

     We depend on strategic collaborators for support in product development and
the regulatory approval process as well as a variety of other activities
including manufacturing, marketing and distribution of our products in the U.S.
and abroad, when, and if, the FDA and corresponding foreign agencies approve our
product candidates for marketing. To date, we have entered into strategic
alliances and collaborations with Schering AG, Tyco/Mallinckrodt, GE Healthcare,
Philips Medical Systems and Siemens Medical Systems. Four of our key agreements
include three collaboration agreements with Schering AG, to perform joint
research and to develop and commercialize MS-325, EP-2104R and other MRI
vascular agents worldwide, and an agreement with Tyco/Mallinckrodt, granting
Tyco/Mallinckrodt rights to enter into an agreement with Schering AG to
manufacture MS-325 for clinical development and commercial use. We may not
receive milestone payments from these alliances should MS-325 or EP-2104R fail
to meet certain performance targets in development and commercialization.
Further, our receipt of revenues from strategic alliances is affected by the
level of efforts of our collaborators. Our collaborators may not devote the
resources necessary to complete development, and commence marketing of MS-325,
EP-2104R or other products in their respective territories, or they may not
successfully market MS-325, EP-2104R or other products. In addition, Schering AG
and Tyco/Mallinckrodt currently manufacture imaging agents for other
technologies that will compete against MS-325 and Schering AG will be
responsible for setting the price of the product worldwide. However, Schering AG
may not set prices in a manner that maximizes revenues for us. We are currently
in compliance with the terms of these agreements, and although we have filed an
NDA, our failure to receive future milestone payments, or a

                                        10


reduction or discontinuance of efforts by our partners would have a material
adverse effect on our business, financial condition and results of operations.

     Furthermore, our collaboration agreement with Schering AG may be terminated
early under certain circumstances, including if there is a material breach of
the agreement by either of us. In addition, we intend to seek additional
collaborations with third parties, who may negotiate provisions that allow them
to terminate their agreements with us prior to the expiration of the negotiated
term under certain circumstances. If Schering AG or any other third party
collaborator were to terminate its agreement with us or otherwise fail to
perform its obligations under our collaboration or to complete them in a timely
manner, we could lose significant revenue. If we are unable to enter into future
strategic alliances with capable partners on commercially reasonable terms, we
may delay the development and commercialization of future product candidates and
could possibly postpone them indefinitely.

     In addition, we rely on certain of our collaborators, such as GE
Healthcare, Siemens Medical Systems and Philips Medical Systems, to develop
software that can be used to enhance or suppress veins or arteries from
MS-325-enhanced MRA images. Although not required for clinical use of MS-325,
the ability to separate veins from arteries using MS-325-enhanced MRA may be
useful to clinicians in reading MS-325-enhanced images for the evaluation of
vascular disease. Therefore, if our collaborators do not develop or implement
the required software successfully, some clinicians may not be able to easily
interpret the information provided from MS-325-enhanced images and therefore may
not be inclined to use the product. Our inability to market MS-325 successfully
to some clinicians may have a material adverse effect on our business.

WE DEPEND ON EXCLUSIVELY LICENSED TECHNOLOGY FROM THE MASSACHUSETTS GENERAL
HOSPITAL AND IF WE LOSE THIS LICENSE, IT IS UNLIKELY WE COULD OBTAIN THIS
TECHNOLOGY ELSEWHERE, WHICH WOULD HAVE A MATERIAL ADVERSE EFFECT ON OUR
BUSINESS.

     Under the terms of a license agreement that we have with Massachusetts
General Hospital, or MGH, we are the exclusive licensee to certain technology,
including patents, which relate to our product candidates, including MS-325. The
license agreement imposes various commercialization, sublicensing, royalty and
other obligations on us. If we fail to comply with these and other requirements,
our license could convert from exclusive to nonexclusive or terminate entirely.
It is unlikely that we would be able to obtain this technology elsewhere. Any
such event would mean that we would be unlikely to produce our product
candidates, including MS-325, and would therefore have a material adverse effect
on our business, financial condition and results of operations. Currently, we
are in compliance with the terms of the license agreement, and we do not have
any reason to believe that this license may be terminated.

WE DEPEND ON PATENTS AND OTHER PROPRIETARY RIGHTS, AND IF THEY FAIL TO PROTECT
OUR BUSINESS, WE MAY NOT BE ABLE TO COMPETE EFFECTIVELY.

     The protection of our proprietary technologies is material to our business
prospects. We pursue patents for our product candidates in the U.S. and in other
countries where we believe that significant market opportunities exist. We own
or have an exclusive license to patents and patent applications on aspects of
our core technology as well as many specific applications of this technology.
Specifically, patents and patent applications related to our core technology
consist of two U.S. patents that are exclusively licensed to us from MGH, as
well as their counterpart patents and applications in foreign countries; seven
U.S. patents and their counterpart patents and applications in certain foreign
countries that we own; 19 U.S. patent applications as well as their counterpart
patents and applications in certain foreign countries and three U.S. provisional
patent applications. One of our issued patents covers aspects of the process by
which MS-325 is manufactured. Another issued patent covers the MS-325
composition of matter. Two of our patents cover certain methods of imaging with
MS-325. We have eight patent applications relating to EP-2104R, fibrin binding
peptides and methods of imaging. Even though we hold these patents and have made
these patent applications, because the patent positions of pharmaceutical and
biopharmaceutical firms, including ours, generally include complex legal and
factual questions, our patent position remains uncertain. For example, because
most patent applications are maintained in secrecy for a period after filing, we
cannot be certain that the named applicants or inventors of the subject matter
covered by our patent applications or patents, whether directly owned or
licensed to us, were the first to invent or the first to file patent
applications for such inventions. Third parties may oppose, challenge, infringe
upon, circumvent or seek to invalidate existing or future patents owned by or
licensed to us. A court or other agency with

                                        11


jurisdiction may find our patents invalid, not infringed or unenforceable and we
cannot be sure that patents will be granted with respect to any of our pending
patent applications or with respect to any patent applications filed by us in
the future. Even if we have valid patents, these patents still may not provide
sufficient protection against competing products or processes. If we are unable
to successfully protect our proprietary methods and technologies, or, if our
patent applications do not result in issued patents, we may not be able to
prevent other companies from practicing our technology and, as a result, our
competitive position may be harmed.

WE MAY NEED TO INITIATE LAWSUITS TO PROTECT OR ENFORCE OUR PATENTS AND OTHER
INTELLECTUAL PROPERTY RIGHTS, WHICH COULD INCUR SUBSTANTIAL COSTS, AND WHICH
COULD RESULT IN THE FORFEITURE OF THESE RIGHTS.

     We may need to bring costly and time-consuming litigation against third
parties in order to enforce our issued patents, protect our trade secrets and
know how, or to determine the enforceability, scope and validity of proprietary
rights of others. In addition to being costly and time-consuming, such lawsuits
could divert management's attention from other business concerns. These lawsuits
could also result in the invalidation or a limitation in the scope of our
patents or forfeiture of the rights associated with our patents or pending
patent applications. We may not prevail and a court may find damages or award
other remedies in favor of an opposing party in any such lawsuits. During the
course of these suits, there may be public announcements of the results of
hearings, motions and other interim proceedings or developments in the
litigation. Securities analysts or investors may perceive these announcements to
be negative, which could cause the market price of our stock to decline. In
addition, the cost of such litigation could have a material adverse effect on
our business and financial condition.

OTHER RIGHTS AND MEASURES THAT WE RELY UPON TO PROTECT OUR INTELLECTUAL PROPERTY
MAY NOT BE ADEQUATE TO PROTECT OUR PRODUCTS AND SERVICES AND COULD REDUCE OUR
ABILITY TO COMPETE IN THE MARKET.

     In addition to patents, we rely on a combination of trade secrets,
copyright and trademark laws, nondisclosure agreements and other contractual
provisions and technical measures to protect our intellectual property rights.
While we require employees, collaborators, consultants and other third parties
to enter into confidentiality and/or non-disclosure agreements where
appropriate, any of the following could still occur:

     -    the agreements may be breached;

     -    we may have inadequate remedies for any breach;

     -    proprietary information could be disclosed to our competitors; or

     -    others may independently develop substantially equivalent proprietary
          information and techniques or otherwise gain access to our trade 
          secrets or disclose such technologies.

     If for any of the above reasons our intellectual property is disclosed or
misappropriated, it would harm our ability to protect our rights and our
competitive position. Moreover, several of our management and scientific
personnel were formerly associated with other pharmaceutical and biotechnology
companies and academic institutions. In some cases, these individuals are
conducting research in similar areas with which they were involved prior to
joining us. As a result, we, as well as these individuals, could be subject to
claims of violation of trade secrets and similar claims.

OUR SUCCESS WILL DEPEND PARTLY ON OUR ABILITY TO OPERATE WITHOUT INFRINGING THE
INTELLECTUAL PROPERTY RIGHTS OF OTHERS, AND IF WE ARE UNABLE TO DO SO, WE MAY
NOT BE ABLE TO SELL OUR PRODUCTS.

     Our commercial success will depend, to a significant degree, on our ability
to operate without infringing upon the patents of others in the U.S. and abroad.
There may be pending or issued patents, held by parties not affiliated with us,
relating to technologies we use in the development or use of certain of our
contrast agents. For example, in November 2003, we entered into an Intellectual
Property Agreement with Dr. Martin R. Prince, an early innovator in the field of
MRA relating to "dynamic" MRA, which involves capturing MRA images during the
limited time, typically 30 to 60 seconds, available for imaging with
extracellular agents. In this Agreement, Dr. Prince made certain covenants and
agreements and granted us certain discharges and releases in connection with the
use of any magnetic

                                        12


resonance imaging drug product containing MS-325. Dr. Prince also granted to us
a non-exclusive license to make, use, sell or otherwise transfer MS-325.
Although we are not aware of any other similar patent claims in the field of
MRA, they may exist.

     If any judicial or administrative proceeding upholds these or any third
party patents as valid and enforceable, we could be prevented from practicing
the subject matter claimed in such patents, or would be required to obtain
licenses from the owners of each such patent, or to redesign our products or
processes to avoid infringement. If we are unable to obtain a required license
on acceptable terms, or are unable to design around these or any third party
patents, we may be unable to sell our products, which would have a material
adverse effect on our business.

EXTENSIVE GOVERNMENT REGULATION MAY DELAY OR PREVENT US FROM MARKETING MS-325 OR
OUR OTHER PRODUCTS UNDER DEVELOPMENT.

     We are subject to extensive U.S. and foreign governmental regulatory
requirements and lengthy approval processes for our product candidates. The
development and commercial use of our product candidates will be regulated by
numerous federal, state, local and foreign governmental authorities in the U.S.,
including the FDA and foreign regulatory agencies. The nature of our research
and development and manufacturing processes requires the use of hazardous
substances and testing on certain laboratory animals. Accordingly, we are
subject to extensive federal, state and local laws, rules, regulations and
policies governing the use, generation, manufacture, storage, air emission,
effluent discharge, handling and disposal of certain materials and wastes, as
well as the use of and care for laboratory animals. Although we believe we are
in compliance with all such laws and maintain policies and procedures to ensure
that we remain in compliance, if we fail to comply or if an accident occurs, we
may be exposed to legal risk and be required to pay significant penalties or be
held liable for any damages that result. Such liability could exceed our
financial resources. Furthermore, current laws could change and new laws could
be passed that may force us to change our policies and procedures, an event
which could impose significant costs on us.

     Specifically, MS-325 is regulated by the FDA as a pharmaceutical product.
The FDA has established substantial requirements for the research, development,
manufacture and marketing of pharmaceutical products. The process required by
the FDA before MS-325 and our other product candidates may be marketed in the
U.S. typically involves the performance of pre-clinical laboratory and animal
tests; submission of an investigational new drug application, or IND; completion
of human clinical trials; submission of a NDA to the FDA; and FDA approval of
the NDA.

     This regulatory approval process is lengthy and expensive. Although some of
our employees have experience in obtaining regulatory approvals, we have only
limited experience in filing or pursuing applications necessary to gain
regulatory approvals. Pre-clinical testing of our product development candidates
is subject to Good Laboratory Practices as prescribed by the FDA and the
manufacture of any products developed by us will be subject to Good
Manufacturing Practices as prescribed by the FDA. We may not obtain the
necessary FDA clearances and subsequent approvals in a timely manner, if at all.
We cannot be sure as to the length of the clinical trial period or the number of
patients that will be required to be tested in the clinical trials in order to
establish the safety and efficacy of MS-325 or any of our future product
candidates. Our clinical trials may not be successful, and we may not complete
them in a timely manner. We could report serious side effects as the clinical
trials proceed. Our results from early clinical trials may not predict results
that we obtain in later clinical trials, even after promising results in earlier
trials. The rate of completion of our clinical trials depends upon, among other
things, the rate of patient enrollment and subsequent blinded reading of images
and data analysis.

     Furthermore, we, the FDA or other regulatory authorities may alter, suspend
or terminate clinical trials at any time. For example, in September 2001, after
discussions with the FDA, we expanded our initial target indication for MS-325
from one specific body region, the aortoiliac region, to a broader indication
that includes the entire body's vascular system, except for the heart. This
expansion required us to add two new clinical trials to our then existing Phase
III clinical trial program, one to determine the efficacy of MS-325-enhanced MRA
for the detection of vascular disease in the renal arteries, and another to
determine the efficacy of MS-325-enhanced MRA for the detection of vascular
disease in the pedal arteries. Although providing us with greater market
potential for the sale of MS-325 upon approval, this change to our Phase III
clinical trial program, and the associated delay in the start up of new clinical

                                        13


centers, resulted in an approximate fifteen month delay in our NDA submission
and an increase in costs associated with the program. If we do not successfully
complete clinical trials for our product candidates, we will not be able to
market these product candidates.

     In addition, we may encounter unanticipated delays or significant costs in
our efforts to secure necessary approvals. In October 2004, we were notified by
the FDA that it had extended the action date for completion of its review of the
MS-325 NDA by 90 days, to January 2005. In communications with the FDA in 
October 2004, the FDA indicated that its principal open review questions 
relate to the non-contrast MRA comparator scans used in the Phase III trials 
and to the statistical treatment of uninterpretable scans. We have 
subsequently provided detailed responses to the FDA's questions. Although we 
remain confident in the safety and efficacy profile of MS-325, the FDA's 
review of the additional analyses and interpretations we have provided could 
adversely affect the approval, timeliness of approval or labeling of MS-325. 
We may not obtain regulatory approval, even after the performance of clinical 
trials and the passage of time and the expenditure of such resources, for 
MS-325 or any other product candidates that we develop. Our analysis of data 
obtained from pre-clinical and clinical activities is subject to confirmation 
and interpretation by regulatory authorities, which could delay, limit or 
prevent FDA regulatory approval. In addition, the FDA may require us to 
modify our future clinical trial plans or to conduct additional clinical 
trials in ways that we cannot currently anticipate, resulting in delays in 
our obtaining regulatory approval. Delays in obtaining government regulatory 
approval could adversely affect our marketing as well as our ability to 
generate significant revenues from commercial sales.

     Future U.S. legislative or administrative actions also could prevent or
delay regulatory approval of our product candidates. Even if we obtain
regulatory approvals, they may include significant limitations on the indicated
uses for which we may market a product. A marketed product also is subject to
continual FDA and other regulatory agency review and regulation. Later discovery
of previously unknown problems or failure to comply with the applicable
regulatory requirements may result in restrictions on the marketing of a product
or withdrawal of the product from the market, as well as possible civil or
criminal sanctions. Further, many academic institutions and companies conducting
research and clinical trials in the MRI contrast agent field are using a variety
of approaches and technologies. If researchers obtain any adverse results in
pre-clinical studies or clinical trials, it could adversely affect the
regulatory environment for MRI contrast agents generally. In addition, if we
obtain marketing approval, the FDA may require post marketing testing and
surveillance programs to monitor the product's efficacy and side effects.
Results of these post-marketing programs may prevent or limit the further
marketing of the monitored product. If we cannot successfully market our
products, we will not generate sufficient revenues to achieve or maintain
profitability.

     Our strategic partners and we are also subject to numerous and varying
foreign regulatory requirements governing the design and conduct of clinical
trials and the manufacturing and marketing of our products. The foreign
regulatory approval process may include all of the risks associated with
obtaining FDA approval set forth above, and we may not obtain foreign regulatory
approvals on a timely basis, if at all, thereby compromising our ability to
market our products abroad.

PRODUCT LIABILITY CLAIMS COULD INCREASE OUR COSTS AND ADVERSELY AFFECT OUR
RESULTS OF OPERATIONS.

     The clinical testing of our approved products, and the manufacturing and
marketing of any approved products may expose us to product liability claims,
and we may experience material product liability losses in the future. We
currently have limited product liability insurance for the use of our product
candidates in clinical research, but our coverage may not continue to be
available on terms acceptable to us or adequate for liabilities we actually
incur. We do not have product liability insurance coverage for the commercial
sale of our products but intend to obtain such coverage when and if we
commercialize our product candidates. However, we may not be able to obtain
adequate additional product liability insurance coverage on acceptable terms, if
at all. A successful claim brought against us in excess of available insurance
coverage, or any claim or product recall that results in significant adverse
publicity against us, may have a material adverse effect on our business and
results of operations.

IF WE FAIL TO GET ADEQUATE LEVELS OF REIMBURSEMENT FROM THIRD PARTY PAYORS FOR
OUR PRODUCT CANDIDATES AFTER THEY ARE APPROVED IN THE U.S. AND ABROAD, WE MAY
HAVE DIFFICULTY COMMERCIALIZING OUR PRODUCT CANDIDATES.

                                        14


     We could be adversely affected by changes in reimbursement policies of
governmental or private healthcare payors, particularly to the extent any such
changes affect reimbursement for procedures in which our product candidates
would be used. Failure by physicians, hospitals and other users of our products
to obtain sufficient reimbursement from third party payors for the procedures in
which our products would be used or adverse changes in governmental and private
third party payors' policies toward reimbursement for such procedures may have a
material adverse effect on our ability to market our products and consequently
it could have an adverse effect on our business, financial condition and results
of operations. If we obtain the necessary foreign regulatory approvals, market
acceptance of our product candidates in international markets would be
dependent, in part, upon the availability of reimbursement within prevailing
healthcare payment systems. Reimbursement and healthcare payment systems in
international markets vary significantly by country, and include both government
sponsored health care and private insurance. We and our strategic partners
intend to seek international reimbursement approvals, although we cannot assure
you that any such approvals will be obtained in a timely manner, if at all, and
failure to receive international reimbursement approvals could have an adverse
effect on market acceptance of our products in the international markets in
which such approvals are sought.

WE DEPEND ON OUR KEY PERSONNEL, THE LOSS OF WHOM WOULD HURT OUR ABILITY TO
COMPETE.

     Our future business and operating results depend in significant part upon
the continued contributions of our senior management and key technical
personnel. If any such personnel were to be hired away from us by a competitor,
or if for any reason, they could not continue to work for us, we could have
difficulty hiring officers with equivalent skills in general, financial and
research management and our ability to achieve our business objectives or to
operate or compete in our industry may be seriously impaired. Although we
maintain key life insurance on our Chief Executive Officer, the loss of any key
employee, the failure of any key employee to perform in his or her current
position, or our inability to attract and retain skilled employees, as needed,
could have a material adverse effect on our business, financial condition and
results of operations. Our future business and operating results also depend in
significant part upon our ability to attract and retain qualified management,
operational and technical personnel. Competition for personnel is intense, and
we may not be successful in attracting or retaining such personnel. If we were
to lose these employees to our competitors, we could spend a significant amount
of time and resources to replace them, which would impair our research and
development or commercialization efforts.

CERTAIN ANTI-TAKEOVER CLAUSES IN OUR CHARTER AND BY-LAW PROVISIONS AND IN
DELAWARE LAW MAY MAKE AN ACQUISITION OF US MORE DIFFICULT.

     Our Restated Certificate of Incorporation authorizes the Board of Directors
to issue, without stockholder approval, up to 1,000,000 shares of preferred
stock with voting, conversion and other rights and preferences that could
adversely affect the voting power or other rights of the holders of Common
Stock. The issuance of Preferred Stock or of rights to purchase Preferred Stock
could be used to discourage an unsolicited acquisition proposal. In addition,
the possible issuance of Preferred Stock could discourage a proxy contest, make
more difficult the acquisition of a substantial block of our Common Stock or
limit the price that investors might be willing to pay for shares of our Common
Stock. The Restated Certificate provides for staggered terms for the members of
the Board of Directors. A staggered Board of Directors and certain provisions of
our By-laws and of Delaware law applicable to us could delay or make more
difficult a merger, tender offer or proxy contest involving us. We, for example,
are subject to Section 203 of the General Corporate Law of Delaware, which,
subject to certain exceptions, restricts certain transactions and business
combinations between a corporation and a stockholder owning 15% or more of the
corporation's outstanding voting stock for a period of three years from the date
the stockholder becomes an interested stockholder. These provisions may have the
effect of delaying or preventing a change in control of us without action by the
stockholders and, therefore, could adversely affect the price of our stock.

                                        15


                       RISKS RELATED TO THE SECURITIES

WE HAVE SIGNIFICANTLY INCREASED OUR LEVERAGE AS A RESULT OF THE SALE OF THE 
NOTES.

         In connection with the sale of the notes, we have incurred new 
indebtedness of $100 million. The amount of our indebtedness could, among 
other things:

         -    make it difficult for us to make payments on the notes;

         -    make it difficult for us to obtain financing for working capital,
              acquisitions or other purposes on favorable terms, if at all;

         -    make us more vulnerable to industry downturns and competitive
              pressures; and

         -    limit our flexibility in planning for, or reacting to changes in,
              our business.

         Our ability to meet our debt service obligations will depend upon our
future performance, which will be subject to financial, business and other
factors affecting our operations, many of which are beyond our control.

YOUR RIGHT TO RECEIVE PAYMENT ON THE NOTES IS JUNIOR TO THE RIGHTS OF THE 
HOLDERS OF THE SCHERING AG LOAN FACILITY AND WILL BE EFFECTIVELY SUBORDINATED 
TO CERTAIN OTHER DEBT.

         The payment of principal and interest on the notes is contractually 
subordinated in right of payment to up to $15.0 million aggregate principal 
amount of indebtedness under the Schering AG loan facility plus accrued and 
unpaid interest. The entire $15 million amount under the loan agreement was 
available and drawn as of September 30, 2004. The entire outstanding balance 
of $15 million, plus accrued interest, was repaid to Schering AG in October 
2004. Of the $15 million available under the loan agreement with Schering 
AG, $7.5 million is available to be redrawn by us until May of 2007 and the 
remaining $7.5 million is available to be redrawn until May 2008, subject to 
specified conditions and covenants contained in the loan agreement. No 
payment will be able to be made in respect of the notes if the indebtedness 
under the 

                                       16



Schering AG loan facility is not paid when due or any other default under the 
Schering AG loan facility occurs and the maturity of such indebtedness is 
accelerated in accordance with its terms. Furthermore, if certain other 
defaults exist with respect to the Schering AG loan facility, the holders of 
such indebtedness will be able to prevent payments on the notes for specified 
periods of time. The Schering AG loan facility is secured by certain of our 
assets. Upon the occurrence of an event of default under the Schering AG loan 
facility, Schering AG will have the ability to foreclose on its security, and 
as a result there may be insufficient assets remaining to pay the amounts due 
on the notes.

         The notes will also be structurally subordinated to the indebtedness 
and other liabilities of any subsidiaries that we may create in the future. 
In addition, the notes are not secured by any of our assets. As a result, the 
notes will be effectively subordinated to any secured debt that we or any 
future subsidiaries may incur to the extent of such security. As a result of 
the effective subordination of the notes to such debt, we may not have 
sufficient assets remaining to pay amounts due on any or all of the notes 
then outstanding in the event of our bankruptcy, liquidation or 
reorganization or upon acceleration of the notes.

         In addition, before we redeem or repurchase for cash the notes in 
whole or in part, we will be required to repay the then outstanding principal 
amount, together with accrued and unpaid interest, under our Schering AG loan 
facility, other than a redemption by us of less than $7.5 million cumulative 
principal amount of the notes. Upon the occurrence of a repayment of the 
Schering AG loan facility there may be insufficient funds available to pay 
the amounts due on the notes.

THE NOTES ARE NOT PROTECTED BY RESTRICTIVE COVENANTS, INCLUDING FINANCIAL 
COVENANTS.

         We are not restricted under the indenture from incurring additional 
debt, including senior debt, or other liabilities. In addition, the indenture 
does not restrict us or any subsidiaries we may create in the future from 
paying dividends or issuing or repurchasing securities. If we or any future 
subsidiaries were to incur additional debt or liabilities, our ability to pay 
our obligations on the notes could be adversely affected. We are not required 



                                        17


under the indenture to meet any financial tests, such as those that measure 
our working capital, interest coverage, fixed charge coverage or net worth, 
in order to maintain compliance with the terms of the indenture covering the 
notes.

WE MAY BE UNABLE TO REPAY, REPURCHASE OR REDEEM THE NOTES.

         At maturity, the entire outstanding principal amount of the notes 
will become due and payable by us. Upon a designated event, as defined in the 
indenture, or upon certain specified dates, you may require us to repurchase 
all or a portion of your notes. We may not have enough funds or be able to 
arrange for additional financing to pay the principal at maturity or to 
repurchase the notes tendered by the holders upon a designated event or upon 
such specified dates. Upon a designated event that is a change in control you 
may not necessarily receive cash as we may elect to pay you the purchase 
price in cash, shares of common stock that are publicly listed on a national 
securities exchange or on Nasdaq, or a combination of both.

         In addition, before we redeem or repurchase for cash the notes in 
whole or in part, we will be required to repay the then outstanding principal 
amount, together with accrued and unpaid interest, under our Schering AG loan 
facility, other than a redemption by us of less than $7.5 million cumulative 
principal amount of the notes. In addition, future credit agreements or other 
agreements relating to our indebtedness may restrict the redemption or 
repurchase of the notes and provide that a change in control constitutes an 
event of default. If the maturity date or a designated event occurs at a time 
when we are prohibited from repaying or repurchasing the notes, we could seek 
the consent of our lenders to purchase the notes or could attempt to 
refinance this debt. If we do not obtain the necessary consents or cannot 
refinance the debt on favorable terms, if at all, we will be unable to repay 
or repurchase the notes. Our failure to repay the notes at maturity or 
repurchase tendered notes would constitute an event of default under the 
indenture, which might constitute a default under the terms of our other debt.


                                        18


YOU MAY NOT HAVE THE RIGHT TO REQUIRE US TO REPURCHASE THE NOTES IN THE EVENT 
OF CERTAIN MERGERS AND SIMILAR TRANSACTIONS.

         The definition of change in control set forth in the indenture
governing the notes is limited and certain mergers and similar transactions are
not deemed a change in control. In such instance, you would not be able to
require us to repurchase the notes. As a result, our obligation to offer to
repurchase the notes upon a change in control will not necessarily afford you
protection in the event of certain highly leveraged transactions, mergers or
similar transactions in which we are involved.

THE CONTINGENT CONVERSION FEATURE OF THE NOTES COULD RESULT IN YOU RECEIVING
LESS THAN THE VALUE OF THE COMMON STOCK INTO WHICH A NOTE WOULD OTHERWISE BE
CONVERTIBLE.

         The notes are convertible into shares of our common stock only if 
specified conditions are met. If the specific conditions for conversion are 
not met, you will not be able to convert your notes, and you may not be able 
to receive the value of the common stock into which the notes would otherwise 
be convertible.

CONVERSION OF THE NOTES WILL DILUTE THE OWNERSHIP INTEREST OF EXISTING 
STOCKHOLDERS.

         The conversion of notes into shares of our common stock will dilute 
the ownership interests of existing stockholders. Any sales in the public 
market of the common stock issuable upon conversion of the notes could 
adversely affect prevailing market prices of our common stock. In addition, 
the existence of the notes may encourage short selling by market participants 
due to this dilution or facilitate trading strategies involving the notes and 
our common stock.

THERE MAY NOT BE AN ACTIVE, LIQUID MARKET FOR OUR COMMON STOCK.

         There is no guarantee that an active trading market for our common 
stock will be maintained on the Nasdaq Stock Market's National Market. 
Investors may not be able to sell their shares quickly or at the latest 
market price if trading in our stock is not active.

                                  19



THE VALUE OF THE CONVERSION RIGHT ASSOCIATED WITH THE NOTES MAY BE 
SUBSTANTIALLY LESSENED OR ELIMINATED IF WE ARE PARTY TO A MERGER, 
CONSOLIDATION OR OTHER SIMILAR TRANSACTION.

         If we are party to a consolidation, merger or binding share exchange 
or transfer or lease of all or substantially all of our assets pursuant to 
which our common stock is converted into cash, securities or other property, 
at the effective time of the transaction, the right to convert a note into 
our common stock will be changed into a right to convert it into the kind and 
amount of cash, securities or other property which the holder would have 
received if the holder had converted its note immediately prior to the 
transaction. Accordingly, upon the consummation of any such transaction, the 
notes may not be convertible into shares of our common stock but rather 
convertible into securities of another entity. This change could 
substantially lessen or eliminate the value of the conversion privilege 
associated with the notes in the future. For example, if we were acquired in 
a cash merger, each note would become convertible solely into cash and would 
no longer be convertible into securities whose value would vary depending on 
our future prospects and other factors.


THE PRICE AT WHICH OUR COMMON STOCK MAY BE PURCHASED ON NASDAQ IS CURRENTLY
LOWER THAN THE CONVERSION PRICE OF THE NOTES AND MAY REMAIN LOWER IN THE FUTURE.

         Prior to electing to convert the notes, the noteholder should 
compare the price at which our common stock is trading in the market to the 
conversion price of the notes. Our common stock trades on the Nasdaq under 
the symbol "EPIX." On November 4, 2004, the last reported closing price of 
our common stock was $16.03 per share. The initial conversion price of the 
notes is approximately $29.77 per share. The market prices of our securities 
are subject to significant fluctuations. Such fluctuations, as well as 
economic conditions generally, may adversely affect the market price of our 
securities, including our common stock and the notes.

                                 20



OUR STOCK PRICE HAS BEEN VOLATILE, AND AN INVESTMENT IN OUR STOCK COULD SUFFER A
DECLINE IN VALUE, ADVERSELY AFFECTING THE VALUE OF THE NOTES OR THE SHARES INTO
WHICH THOSE NOTES MAY BE CONVERTED.

         The market prices of the capital stock of medical technology companies
have historically been very volatile, and the market price of the shares of our
common stock fluctuates. The market price of our common stock is affected by
numerous factors, including:

         -    actual or anticipated fluctuations in our operating results;

         -    announcements of technological innovation or new commercial
              products by us or our competitors;

         -    new collaborations entered into by us or our competitors;

         -    developments with respect to proprietary rights, including patent
              and litigation matters;

         -    results of pre-clinical and clinical trials;

         -    conditions and trends in the pharmaceutical and other technology
              industries;

         -    adoption of new accounting standards affecting such industries;

         -    changes in financial estimates by securities analysts; and

         -    degree of trading liquidity in our common stock and general market
              conditions.

         During the nine months ended September 30, 2004, the closing price 
of our common stock ranged from $25.99 to $15.86. The last reported closing 
price for our common stock on November 4, 2004 was $16.03. If our stock price 
declines significantly, we may be unable to raise additional capital. 
Significant declines in the price of our common stock could also impede our 
ability to attract and retain qualified employees and reduce the liquidity of 
our common stock.

                                      21



         In addition, the stock market has from time to time experienced 
significant price and volume fluctuations that have particularly affected the 
market prices for the common stock of similarly staged companies. These broad 
market fluctuations may adversely affect the market price of our common 
stock. In the past, following periods of volatility in the market price of a 
particular company's securities, shareholders have often brought class action 
securities litigation against that company. Such litigation, if brought 
against us, could result in substantial costs and a diversion of management's 
attention and resources.

THE CONVERSION CONTINGENCY PROVISIONS OF THE NOTES MAY CAUSE A DECREASE IN 
OUR EARNINGS PER SHARE ON A DILUTED BASIS OR MAKE OUR REPORTED EARNINGS PER 
SHARE MORE VOLATILE, POTENTIALLY AFFECTING OUR SHARE PRICE AND THE AMOUNT YOU 
MAY RECEIVE UPON SALE OR CONVERSION OF THE NOTES.

         Holders of the notes are entitled to convert the notes into shares 
of our common stock, among other circumstances, if the price of our common 
stock for the periods described in this prospectus is more than 120% of the 
conversion price of the notes. Under current accounting rules, unless and 
until this contingency or another conversion contingency is met, the shares 
of our common stock underlying the notes generally will not be included in 
the calculation of our basic and diluted earnings per share. If this 
contingency is met or would have been met if measured instead at the end of 
the reporting period, any diluted earnings per share that we may earn would 
be expected to decrease as a result of the inclusion of the underlying shares 
in the diluted earnings per share calculation. Volatility in our stock price 
could cause this condition to be met in one quarter and not in a subsequent 
quarter, increasing the volatility of our diluted earnings per share.


                                   22



FUTURE SALES OF OUR COMMON STOCK IN THE PUBLIC MARKET COULD ADVERSELY AFFECT 
THE TRADING PRICE OF OUR COMMON STOCK, THE VALUE OF THE NOTES AND OUR ABILITY 
TO RAISE FUNDS IN NEW STOCK OFFERINGS.

         Future sales of substantial amounts of our common stock in the 
public market, or the perception that such sales are likely to occur, could 
affect prevailing trading prices of our common stock and the value of the 
notes. As of September 30, 2004, we had:

         -    23,089,499 shares of common stock outstanding;

         -    3,687,615 shares of common stock underlying options outstanding
              at a weighted average exercise price of $12.09 per share; and

         -    710,702 shares of common stock that have been reserved for
              issuance upon future grants under our stock option plans; and

         -    42,832 shares available for issuance under our employee stock
              purchase plan.

         Because the notes generally are convertible into common stock only at a
conversion price in excess of the recent trading price, a decline in our common
stock price may cause the value of the notes to decline.


                                   23



                           FORWARD-LOOKING STATEMENTS

         This prospectus and the documents incorporated by reference contain
forward-looking statements within the meaning of Section 27A of the Securities
Act and Section 21E of the Securities Exchange Act of 1934, as amended, or the
Exchange Act. These statements can be identified by the use of forward-looking
terminology such as "may," "will," "could," "expect," "anticipate," "estimate,"
"continue" or other similar expressions or the negative of such terms or other
comparable terminology. You should carefully read statements that contain these
words because they discuss our future expectations, contain projections of our
future results of operations or of our financial position, or state other
"forward-looking" information. We believe that it is important to communicate
our future expectations to our investors. However, there may be events in the
future that we are not able to accurately predict or control. The factors listed
above in the section captioned "Risk Factors," as well as any cautionary
language in this prospectus, provide examples of risks, uncertainties and events
that may cause our actual results to differ materially from the expectations we
describe in our forward-looking statements. Before you invest, you should be
aware that the occurrence of the events described in these risk factors and
elsewhere in this prospectus could have a material adverse effect on our
business, results of operations and financial position. We do not intend to
update any forward-looking statements to conform to actual result unless
required by law.

                       RATIO OF EARNINGS TO FIXED CHARGES

         We have not recorded earnings for any fiscal year since inception and
therefore have no earnings to cover fixed charges. Fixed charges consists of
interest expense, amortization of debt issuance costs and a portion of rental
expense that we believe to be representative of interest. The following table
discloses our dollar coverage deficiency. The ratio of earnings to fixed charges
is not disclosed since it is a negative number in each year and period.



                                                              FOR THE YEARS ENDED DECEMBER 31,
                          NINE MONTHS ENDED  -----------------------------------------------------------------
     (in thousands)      SEPTEMBER 30, 2004      2003          2002         2001          2000         1999
                         ------------------  ----------    ----------   ----------    ----------    ----------
                                                                                  
Deficiency of earnings
available to cover
    fixed charges           $  (15,192)      $  (20,714)   $  (22,098)  $  (18,156)   $  (22,957)   $  (16,983)
                            ==========       ==========    ==========   ==========    ==========    ==========


                                 USE OF PROCEEDS

         All of the notes and the shares of common stock issuable upon
conversion of the notes are being sold by the selling holders or by their
pledgees, donees, transferees or other successors in interest. We will not
receive any proceeds from the sale of the notes or the shares of our common
stock issuable upon conversion of the notes.

         The selling holders will pay any underwriting discounts and commissions
and expenses incurred by the selling holders for brokerage, accounting, tax or
legal services or any other expenses incurred by the selling holders in
disposing of the notes and the shares. We will bear all other costs, fees and
expenses incurred in effecting the registration of the notes and shares covered
by this prospectus, including, without limitation, all registration and filing
fees, and fees and expenses of our counsel and our accountants.

                                       24


                              DESCRIPTION OF NOTES

         We issued the notes under an indenture dated as of June 7, 2004 between
us, as issuer, and U.S. Bank National Association, as trustee. The notes and the
shares of common stock issuable upon conversion of the notes are covered by a
registration rights agreement. The indenture and the registration rights
agreement have been publicly filed by us and they are incorporated herein by
reference.

         The following description is a summary of the material provisions of
the notes, the indenture and the registration rights agreement. It does not
purport to be complete. This summary is subject to and is qualified by reference
to all the provisions of the indenture, including the definitions of certain
terms used in the indenture. Wherever particular provisions or defined terms of
the indenture or form of note are referred to, these provisions or defined terms
are incorporated in this prospectus by reference. We urge you to read the
indenture because it, and not this description, defines your rights as a holder
of notes.

         As used in this "Description of Notes" section, references to "EPIX,"
"we," "our" or "us" refer solely to EPIX Pharmaceuticals, Inc.

         GENERAL

         The notes are general, unsecured, senior obligations of EPIX, and are
subordinated in right of payment to existing and future indebtedness under our
Schering AG loan facility and are effectively subordinated in right of payment
to our existing and future secured debt, to the extent of the security, and the
liabilities of any subsidiaries that we may create in the future as described
under "--Ranking," but are senior in right of payment to all subordinated
indebtedness that by its terms treats the notes as senior indebtedness. In
addition, the notes will rank on a parity in right of payment with all of our
existing and future unsecured senior debt, other than existing and future
indebtedness under our Schering AG loan facility. The notes will not be
obligations of, or guaranteed by, any subsidiaries that we may create in the
future. The notes are convertible into common stock as described under
"--Conversion of Notes."

         The notes are limited to $100 million aggregate principal amount and
have been issued only in denominations of $1,000 and multiples of $1,000. We use
the term "note" in this prospectus to refer to each $1,000 principal amount of
notes. The notes will mature on June 15, 2024, unless earlier converted,
redeemed or repurchased.

         We may from time to time repurchase the notes in open market purchases
or negotiated transactions without prior notice to holders.

         If we experience a change in control or a termination of trading, you
will have the right to require us to repurchase your notes as described below
under "--Repurchase at the Option of the Holder Upon a Designated Event."
Holders of notes who have submitted a notice of repurchase will be entitled,
upon a valid withdrawal of such notice, to convert the notes up to and including
the business day immediately preceding the date fixed for repurchase.

         Neither we nor any subsidiaries that we may create in the future will
be subject to any financial covenants under the indenture. In addition, neither
we nor any of such subsidiaries are restricted under the indenture from paying
dividends, making investments, incurring debt, including additional senior
indebtedness, granting liens or mortgages, or issuing or repurchasing our
securities.

         We will pay interest at a rate of 3.00% per annum, and additional
interest, if any, semi-annually in arrears on June 15 and December 15 of each
year, beginning December 15, 2004, to record holders at the close of business on
the preceding June 1 and December 1, as the case may be. Interest will be
computed on the basis of a 360-day year composed of twelve 30-day months. In
addition, in the event of certain registration defaults, we will accrue
additional amounts of interest. For a description of these additional amounts,
see the section entitled "--Registration Rights of the Noteholders."

         We will maintain an office or agency in the Borough of Manhattan, The
City of New York, where we will pay the principal on the notes and where you may
present the notes for conversion, registration of transfer or exchange for other
denominations, which shall initially be an office or agency of the trustee. We
may pay interest by check mailed to your address as it appears in the note
register, provided that if you are a holder of an aggregate principal amount of
notes in

                                       25


excess of $2,000,000, you shall be paid, at your written election, by wire
transfer in immediately available funds. However, payments to The Depository
Trust Company, New York, New York, which we refer to as DTC, will be made by
wire transfer of immediately available funds to the account of DTC or its
nominee.

         The notes are not subject to a sinking fund provision and are not
subject to defeasance or covenant defeasance under the indenture.

         CONVERSION OF NOTES

         The conversion rate will be equal to the number of shares per $1,000
principal amount of notes shown on the cover page of this prospectus subject to
adjustment as specified below. The initial conversion rate is equivalent to a
conversion price of approximately $29.77. The conversion price is equal to
$1,000 principal amount of notes divided by the conversion rate. You will have
the right to convert any portion of the principal amount of any note that is an
integral multiple of $1,000 into shares of our common stock as follows:

         -    if, on or prior to June 15, 2019, the closing sale price of our
              common stock, for at least 20 trading days in the period of the 30
              consecutive trading days ending on the eleventh trading day of any
              fiscal quarter, is more than 120% of the then current conversion
              price of the notes, then you will have such conversion right until
              and including the eleventh trading day of the following fiscal
              quarter;

         -    if, on any date after June 15, 2019, the closing sale price of our
              common stock is more than 120% of the then current conversion
              price of the notes, then you will have such conversion right at
              all times thereafter;

         -    if we elect to call the notes for redemption, then you will have
              the right to convert the notes (or the portion of notes called for
              redemption, if less than all) until the close of business on the
              business day prior to the redemption date;

         -    if we distribute to all or substantially all holders of our common
              stock, rights, options or warrants entitling them to purchase our
              common stock at less than the closing sale price of our common
              stock on the day preceding the declaration for such distribution,
              then you will have such conversion right in the period described
              below;

         -    if we distribute to all or substantially all holders of our common
              stock, cash, assets, debt securities or capital stock of any
              subsidiaries that we may create in the future, which distribution
              has a per share value as determined by our board of directors
              exceeding 5% of the closing sale price of our common stock on the
              day preceding the declaration of such distribution, then you will
              have such conversion right in the period described below; or

         -    if we become a party to a consolidation, merger or sale of all or
              substantially all of our assets that constitutes a change in
              control as defined below under the heading "--Repurchase at the
              Option of the Holder Upon a Designated Event" or such event occurs
              that would have been a change in control but for one or both of
              the exceptions to the definition of change in control included
              below, under the same heading, in the paragraph immediately
              following subparagraph (3).

         A note for which a holder has delivered a repurchase notice as
described below may be surrendered for conversion only if the repurchase notice
is withdrawn in accordance with the indenture.

         In the case of the fourth and fifth bullet points above, we must notify
holders of notes at least 20 days prior to the ex-dividend date for such
distribution. Once we have given such notice, holders may surrender their notes
for conversion at any time until the earlier of the close of business on the
business day prior to the ex-dividend date or our announcement that such
distribution will not take place. If in the future we adopt a shareholder rights
plan, you will not have any conversion right pursuant to the fourth bullet point
above or otherwise, solely as a result of the issuance of rights pursuant to the
shareholder rights plan. In the case of a distribution identified in the fourth
or fifth bullet points above, the ability of a holder of notes to convert would
not be triggered if the holder may participate in the distribution without
converting. In the case of the sixth bullet point above, a holder may surrender
notes for conversion at any time from and after the date which is 15 days prior
to the anticipated effective date of the transaction until 15 days after the
actual date of the

                                       26


transaction. As used in this section, "closing sale price" generally means the
last reported sale price of our common stock on the Nasdaq.

         In addition, at any time prior to June 15, 2019, you may convert your
notes into shares of our common stock for the five business-day period after any
five consecutive trading-day period in which the average trading price for the
notes in such period was less than 98% of the average conversion value (as
defined below) for the notes during that period.

         The "trading price" of the notes on any date of determination means the
average of the secondary market bid quotations per $1,000 principal amount of
the notes obtained by the trustee for $2,000,000 principal amount of the notes
at approximately 3:30 p.m., New York City time, on such determination date from
three independent nationally recognized securities dealers we select; provided
that if three such bids cannot reasonably be obtained by the trustee, but two
such bids are obtained, then the average of the two bids shall be used, and if
only one such bid can reasonably be obtained by the trustee, then one bid shall
be used. If the trustee cannot reasonably obtain at least one bid for $2,000,000
principal amount of the notes from a nationally recognized securities dealer,
then the trading price per $1,000 principal amount of notes will be deemed to be
less than 98% of the product of the closing sale price of our common stock and
the number of shares issuable upon conversion of $1,000 principal amount of the
notes.

         In connection with any conversion upon satisfaction of the trading
price condition, the trustee shall have no obligation to determine the trading
price of the notes unless we have requested such determination; and we shall
have no obligation to make such request unless you provide us with reasonable
evidence that the trading price per $1,000 principal amount of notes would be
less than 98% of the product of the closing sale price of our common stock and
the number of shares of common stock issuable upon conversion of $1,000
principal amount of the notes. At that time, we shall instruct the trustee to
determine the trading price of the notes beginning on the next trading date and
on each successive trading day until the trading price per $1,000 principal
amount of notes is greater than or equal to 98% of the product of the closing
sale price of our common stock and the number of shares issuable upon conversion
of $1,000 principal amount of the notes.

         We define conversion value in the indenture to be equal to the product
of the closing sale price of our shares of common stock on a given day
multiplied by the then current conversion rate, which is the number of shares of
common stock into which each $1,000 principal amount of the notes is
convertible.

         You may convert all or part of any note that is an integral multiple of
$1,000 as permitted above by delivering the note at the Corporate Trust Office
of the trustee in the Borough of Manhattan, The City of New York, accompanied by
a duly signed and completed irrevocable conversion notice, a copy of which may
be obtained by the trustee, and any applicable payments, including interest
payments and payments in respect of taxes, if any. The conversion date will be
the date on which the note and the duly signed and completed conversion notice
are so delivered.

         As promptly as practicable on or after the conversion date, we will
issue and deliver to the trustee a certificate or certificates for the number of
full shares of our common stock issuable upon conversion, together with payment
in lieu of any fraction of a share. The certificate will then be sent by the
trustee to the conversion agent for delivery to the holder. The shares of our
common stock issuable upon conversion of the notes will be fully paid and
nonassessable and will rank equally with the other shares of our common stock.

         If you surrender a note for conversion on a date that is not an
interest payment date, you will not be entitled to receive any interest for the
period from the immediately preceding interest payment date to the conversion
date, except as described below in this paragraph. In the case of any note that
has been surrendered for conversion after any regular record date but before the
next succeeding interest payment date:

         -    notwithstanding such conversion, interest payable on such interest
              payment date shall be payable on such interest payment date, and
              such interest shall be paid to the holder of such note as of such
              regular record date; and

         -    except for notes, or portions thereof, called for redemption or to
              be purchased or repurchased after a regular record date but on or
              prior to such interest payment date, or to the extent of overdue
              interest if we are in arrears on our interest payments as of the
              conversion date, such notes surrendered for conversion must be

                                       27


              accompanied by payment of an amount equal to the interest payable
              on such interest payment date on the principal amount of notes
              being surrendered for conversion.

         No other payment or adjustment for interest, or any dividends in
respect of our common stock, will be made upon conversion. Holders of our common
stock issued upon conversion will not be entitled to receive any dividends
payable to holders of our common stock as of any record time or date before the
close of business on the conversion date. We will not issue fractional shares
upon conversion. Instead, we will pay cash based on the closing sale price of
our common stock at the close of business on the conversion date.

         You will not be required to pay any taxes or duties relating to the
issue or delivery of our common stock on conversion, but you will be required to
pay any tax or duty relating to any transfer involved in the issue or delivery
of our common stock in a name other than yours. Certificates representing shares
of our common stock will not be issued or delivered unless all taxes and duties,
if any, payable by you have been paid.

         The conversion rate will be subject to adjustment for, among other
things:

         -    dividends and other distributions payable in our common stock on
              shares of our common stock;

         -    the issuance to all holders of our common stock of rights, options
              or warrants (in any case other than in connection with a
              shareholder rights plan) entitling them to subscribe for or
              purchase our common stock at less than the current market price of
              such common stock on the record date for stockholders entitled to
              receive such rights, options or warrants;

         -    subdivisions, combinations, splits, reverse splits and
              reclassifications of our common stock;

         -    distributions to all holders of our common stock of evidences of
              our indebtedness, shares of capital stock, cash or assets (if we
              distribute shares of capital stock of any subsidiary that we may
              create in the future, the conversion rate will be adjusted, if at
              all, based on the market value of the subsidiary stock so
              distributed relative to the market value of our common stock, in
              each case over a measurement period following the distribution),
              including securities, but excluding:

              -    those dividends, rights, options, warrants and distributions
                   referred to above;

              -    dividends and distributions paid exclusively in cash; and

              -    distributions upon mergers or consolidations discussed below.

         -    if we or a subsidiary that we may create in the future purchase
              our common stock (excluding options, warrants, purchase rights and
              other securities convertible, exchangeable or exercisable for
              common stock) pursuant to a tender or exchange offer for our
              common stock, to the extent that the cash and value of any other
              consideration included in the payment per share of common stock in
              such offer exceeds the closing sale price of our common stock on
              the trading day next succeeding the last date on which tenders or
              exchanges may be made pursuant to such tender or exchange offer,
              then the conversion rate will be adjusted; and

         -    if we make a distribution consisting exclusively of cash to all
              holders of outstanding shares of common stock, the conversion rate
              will be adjusted to a new conversion rate equal to the existing
              conversion rate multiplied by a fraction, the numerator of which
              is the current market price of our common stock plus the amount
              per share of such dividend or distribution and the denominator of
              which will be the current market price of our common stock, where
              the current market price of our common stock is the average
              closing sale price of our common stock for the first 10 trading
              days from, and including, the first ex-distribution day that the
              common stock trades.

         To the extent that we have a shareholder rights plan in effect upon
conversion of the notes into common stock, you will receive, in addition to the
common stock, the rights under the rights plan unless the rights have separated
from the common stock before the time of conversion, in which case the
conversion rate will be adjusted as if we distributed to

                                       28


all holders of our common stock, shares of our capital stock, evidences of
indebtedness or assets as described above, subject to readjustment in the event
of the expiration, termination or redemption of such rights.

         We reserve the right to effect such increases in the conversion rate in
addition to those required by the foregoing provisions as we consider to be
advisable in order that any event treated for U.S. federal income tax purposes
as a distribution of stock or stock rights will not be taxable to the
recipients. We will not be required to make any adjustment to the conversion
rate until the cumulative adjustments amount to 1.0% or more of the conversion
rate. We will compute all adjustments to the conversion rate and will give
notice by mail to holders of the registered notes of any adjustments.

         In the event that we consolidate or merge with or into another entity
or another entity is merged into us, or in case of any sale or transfer of all
or substantially all of our assets, each note then outstanding will become
convertible only into the kind and amount of securities, cash and other property
receivable upon such consolidation, merger, sale or transfer by a holder of the
number of shares of common stock into which the notes were convertible
immediately prior to the consolidation or merger or sale or transfer. The
preceding sentence will not apply to a merger or sale of all or substantially
all of our assets that does not result in any reclassification, conversion,
exchange or cancellation of our common stock.

         We may increase the conversion rate if our board of directors
determines that the increase would be in our best interest. The board of
directors' determination in this regard will be conclusive. We will give holders
of notes notice of such an increase in the conversion rate. We will comply with
the Exchange Act and the rules and regulations promulgated under the Exchange
Act, to the extent applicable, in connection with any such notice.

         If at any time we make a distribution of property to our stockholders
that would be taxable to such stockholders as a dividend for U.S. federal income
tax purposes, such as distributions of evidences of indebtedness or assets by
us, but generally not stock dividends on common stock or rights to subscribe for
common stock, and, pursuant to the conversion price adjustment provisions of the
indenture, the number of shares into which notes are convertible is increased,
that increase may be deemed for U.S. federal income tax purposes to be the
payment of a taxable dividend to holders of notes. See "Certain U.S. Federal
Income Tax Considerations."

         OPTIONAL REDEMPTION BY EPIX

         On or after June 15, 2009, we may redeem the notes, in whole or in
part, at the following percentages of the principal amount of the notes, plus
accrued and unpaid interest and additional interest, if any, to, but excluding,
the redemption date:



                               DATE                             REDEMPTION PRICE
         -----------------------------------------------        ----------------
                                                                 
         June 15, 2009 to June 14, 2010.................            100.857%
         June 15, 2010 to June 14, 2011.................            100.429%
         June 15, 2011 and thereafter...................            100.000%


         If we elect to redeem all or part of the notes, we will give at least
20, but no more than 60, days' prior notice to you. If we do not redeem all of
the notes, the trustee will select the notes to be redeemed in principal amounts
of $1,000 or whole multiples of $1,000 by lot, on a pro rata basis or otherwise
in accordance with the applicable procedures of the depository. If any notes are
to be redeemed in part only, we will issue a new note or notes in principal
amount equal to the unredeemed principal portion thereof.

         No sinking fund is provided for the notes, which means that the
indenture does not require us to redeem or retire the notes periodically.

         We may not redeem the notes if we have failed to pay any interest on
the notes and such failure to pay is continuing, or if the principal amount of
the notes has been accelerated.

         If we redeem the notes in whole or in part, other than a redemption of
less than $7.5 million in cumulative principal amount of the notes, then we will
be required to repay the then outstanding principal amount, together with
accrued and unpaid interest, under our Schering AG loan facility.

                                       29


         REPURCHASE AT THE OPTION OF THE HOLDER ON SPECIFIED DATES

         On the repurchase date of each of June 15, 2011, 2014 and 2019, we
will, at the option of the holder, be required to repurchase for cash any
outstanding note for which a written repurchase notice has been properly
delivered by the holder and not withdrawn, subject to certain additional
conditions. Holders may submit their notes for repurchase to the paying agent at
any time from the opening of business on the date that is 20 business days prior
to such repurchase date until the close of business on such repurchase date. The
repurchase price of a note will be 100% of the principal amount of the note,
plus accrued and unpaid interest and additional interest, if any, to, but
excluding, the repurchase date. Interest and additional interest, if any, will
be paid to the record holder as of the related record date.

         We will be required to give notice on a date not less than 20 business
days prior to the repurchase date to all holders at their addresses shown in the
register of the registrar, and to beneficial owners as required by applicable
law, stating, among other things, the procedures that holders must follow to
require us to repurchase their notes.

         The repurchase notice given by each holder electing to require us to
repurchase notes shall state:

         -    if certificated notes have been issued, the certificate numbers of
              the holder's notes to be delivered for repurchase or, if not, such
              information as may be required under applicable DTC procedures and
              the indenture;

         -    the portion of the principal amount of notes to be repurchased,
              which must be $1,000 or an integral multiple of $1,000 (or the
              entire principal amount of the notes held by such holder); and

         -    that the notes are to be repurchased by us pursuant to the
              applicable provisions of the notes and the indenture.

         Any repurchase notice may be withdrawn by the holder by a written
notice of withdrawal delivered to the paying agent prior to the close of
business on the repurchase date. The notice of withdrawal shall state:

         -    the principal amount being withdrawn;

         -    if certificated notes have been issued, the certificate numbers of
              the notes being withdrawn or, if not, such information as may be
              required under applicable DTC procedures and the indenture; and

         -    the principal amount, if any, of the notes that remains subject to
              the repurchase notice.

         Payment of the repurchase price for a note for which a repurchase
notice has been delivered and not validly withdrawn is conditioned upon delivery
(including by book entry transfer) of the note, together with necessary
endorsements, to the paying agent at any time after delivery of the repurchase
notice. Payment of the repurchase price for the note will be made promptly
following the later of the repurchase date or the time of delivery of the note.

         If the paying agent holds money or securities sufficient to pay the
repurchase price of the note on the repurchase date then, on and after the
business day following the repurchase date:

         -    the note will cease to be outstanding;

         -    interest will cease to accrue in respect of any date from and
              after the repurchase date; and

         -    all other rights of the holder will terminate, other than the
              right to receive the repurchase price upon delivery of the note.

         Before we repurchase the notes in whole or in part, we will be required
to repay the then outstanding principal amount, together with accrued and unpaid
interest, under our Schering AG loan facility.

         Our ability to repurchase notes with cash may be limited by the terms
of our then existing borrowing and other financing agreements. Also, as
described in the "Risk Factors" section of this prospectus, we may not have
sufficient

                                       30


funds to repurchase the notes when we are required to do so. We will comply with
the Exchange Act and the rules and regulations promulgated under the Exchange
Act, to the extent applicable, in connection with any such repurchase.

         REPURCHASE AT THE OPTION OF THE HOLDER UPON A DESIGNATED EVENT

         If a designated event occurs at any time prior to the maturity of the
notes, you may require us to repurchase your notes, in whole or in part, on a
repurchase date that is not less than 30 nor more than 45 business days after
the date of our notice of the designated event. The notes will be repurchased
only in integral multiples of $1,000 principal amount (or the entire principal
amount of the notes held by any holder).

         We will repurchase the notes at a price equal to 100% of the principal
amount to be repurchased, plus accrued and unpaid interest and additional
interest, if any, to, but excluding, the repurchase date. If such repurchase
date falls after a record date and on or prior to the corresponding interest
payment date, we will pay the full amount of accrued and unpaid interest payable
on such interest payment date to the holder of record on the close of business
on the corresponding record date.

         We will mail to all record holders a notice of a designated event
within 20 days after it has occurred. We also are required to deliver to the
trustee a copy of the designated event notice. If you elect to require us to
repurchase your notes, you must deliver to us or our designated agent, prior to
the close of business on the repurchase date specified in our designated event
notice, your repurchase notice and any notes to be repurchased, duly endorsed
for transfer (or, if your notes are not certificated, your repurchase notice
must comply with appropriate DTC procedures). We will promptly pay the
repurchase price for notes surrendered for repurchase following the repurchase
date.

         You may withdraw any written repurchase notice by delivering a written
notice of withdrawal to the paying agent prior to the close of business on the
repurchase date. The withdrawal notice must state:

         -    the principal amount of the withdrawn notes;

         -    if certificated notes have been issued, the certificate number of
              the withdrawn notes (or, if your notes are not certificated, your
              withdrawal notice must comply with appropriate DTC procedures);
              and

         -    the principal amount, if any, which remains subject to the
              repurchase notice.

         In the event of a "termination of trading," we will pay the repurchase
price in cash.

         In the event of a "change in control," we may, at our option, elect to
pay the repurchase price in cash, shares of common stock valued at a discount of
5% from the market price of our common stock, or any combination thereof. If the
amount of stock to be issued in connection with any repurchase equals or exceeds
20% of the voting power of our outstanding stock prior to the issuance in
connection with the repurchase, we may, under Nasdaq rules, be required to
obtain the approval of our stockholders for such an issuance. We may pay the
repurchase price in shares of our common stock only if such shares are eligible
for immediate resale in the public market by our non-affiliates. We will notify
the holders of the notes upon the determination of the actual number of shares
of common stock deliverable upon any repurchase of the notes.

         Our right to repurchase the notes, in whole or in part, in the event of
a change in control with shares of common stock is subject to our satisfying
various conditions, including:

         -    the listing of such shares of common stock on the principal United
              States securities exchange on which the common stock is then
              listed or, if not so listed, on Nasdaq or any similar U.S. system
              of automated dissemination of quotations of securities prices;

         -    the registration of the common stock under the Exchange Act, if
              required; and

         -    any necessary qualification or registration under applicable state
              securities law or the availability of an exemption from such
              qualification and registration.

                                       31


         If such conditions are not satisfied with respect to a holder prior to
the close of business on the repurchase date, we will pay the repurchase price
of such holder's notes entirely in cash. We may not change the form or
components or percentages of components of consideration to be paid for the
notes once we have given any notice that we are required to give to holders of
the notes, except as described in the first sentence of this paragraph.

         The "market price" of our common stock means the average of the daily
volume-weighted average price of our common stock for the 20 trading-day period
ending on the third business day prior to the repurchase date (if the third
business day prior to the repurchase date is a trading day, or if not, then on
the last trading day prior to the third business day), appropriately adjusted to
take into account the occurrence, during the period commencing on the first
trading day during the 20 trading-day period and ending on the repurchase date,
of any event that would result in an adjustment to the conversion rate of the
notes, as described above under "--Conversion of Notes."

         Because the market price of our common stock is determined prior to the
repurchase date, holders of the notes bear the market risk with respect to the
value of our common stock to be received from the date the market price is
determined to the repurchase date. We may pay the repurchase price or any
portion of the repurchase price in shares of our common stock only if the
information necessary to calculate the market price is publicly available. In
connection with any redemption offer, we will comply with the provisions of Rule
13e-4, Rule 14e-1 and any other tender offer rules under the Exchange Act that
may then be applicable, including filing a Schedule TO or any other required
schedule under the Exchange Act.

         Payment of the repurchase price for a note for which a repurchase
notice has been delivered and not withdrawn is conditioned upon book-entry
transfer or delivery of the note, together with necessary endorsements, to the
paying agent at its corporate trust office in the Borough of Manhattan, The City
of New York, or any other office of the paying agent, at any time after delivery
of the repurchase notice. Payment of the repurchase price for the note will be
made promptly following the later of the repurchase date and the time of
book-entry transfer or delivery of the note.

         If the paying agent holds money or securities sufficient to pay the
repurchase price of the note on the repurchase date, then, on and after the
business day following the repurchase date:

         -    the note will cease to be outstanding;

         -    interest will cease to accrue in respect of any date from and
              after the repurchase date; and

         -    all other rights of the holder will terminate, other than the
              right to receive the repurchase price upon delivery of the note.

         This will be the case whether or not book-entry transfer of the note
has been made or the note has been delivered to the paying agent.

         A "designated event" will be deemed to have occurred upon a change in
control or a termination of trading.

         A "change in control" will be deemed to have occurred at the time after
the notes are originally issued that any of the following occurs:

         (1)  any person acquires a beneficial ownership, directly or
              indirectly, through a purchase, merger or other acquisition
              transaction or series of transactions, of shares of our capital
              stock entitling the person to exercise 50% or more of the total
              voting power of all shares of our capital stock that are entitled
              to vote generally in elections of directors, other than an
              acquisition by us, any subsidiaries that we may create in the
              future or any of our employee benefit plans; or

         (2)  we merge or consolidate with or into any other person, any other
              person merges with or into us or we convey, sell, transfer or
              lease all or substantially all of our assets to another person,
              other than:

              -    any such transaction pursuant to which the holders of 50% or
                   more of the total voting power of all shares of our capital
                   stock entitled to vote generally in elections of directors
                   immediately prior to such transaction have the entitlement to
                   exercise, directly or indirectly, 50% or more of the total
                   voting

                                       32


                   power of all shares of capital stock entitled to vote
                   generally in the election of directors of the continuing or
                   surviving corporation immediately after such transaction; or

              -    any merger that is effected solely to change our jurisdiction
                   of incorporation; or

         (3)  any transaction or event (whether by means of an exchange offer,
              liquidation, tender offer, consolidation, merger, binding share
              exchange, combination, reclassification, recapitalization or
              otherwise) in connection with which all or substantially all of
              our common stock is exchanged for, converted into, acquired for or
              constitutes solely the right to receive, consideration which is
              not all or substantially all common stock that:

              -    is listed on, or immediately after the transaction or event
                   will be listed on, a U.S. national securities exchange; or

              -    is approved, or immediately after the transaction or event
                   will be approved, for quotation on Nasdaq or any similar U.S.
                   system of automated dissemination of quotations of securities
                   prices.

         HOWEVER, A CHANGE IN CONTROL WILL NOT BE DEEMED TO HAVE OCCURRED IF
EITHER:

              -    the closing price per share of our common stock for any five
                   trading days within the period of 10 consecutive trading days
                   ending immediately after the later of the change in control
                   and the public announcement of the change in control, in the
                   case of a change in control relating to an acquisition of
                   capital stock, or the period of 10 consecutive trading days
                   ending immediately before the change in control, in the case
                   of a change in control relating to a merger, consolidation or
                   asset sale, equals or exceeds 105% of the conversion price of
                   the notes in effect on each of those trading days; or

              -    all of the consideration, excluding cash payments for
                   fractional shares and cash payments made pursuant to
                   dissenters' appraisal rights, in a merger or consolidation
                   otherwise constituting a change in control under clause (1)
                   or (2) in the preceding paragraph above, consists of shares
                   of common stock, depositary receipts or other certificates
                   representing common equity interests traded on a national
                   securities exchange or quoted on Nasdaq, or will be so traded
                   or quoted immediately following such merger or consolidation,
                   and as a result of such merger or consolidation the notes
                   become convertible solely into such common stock, depositary
                   receipts or other certificates representing common equity
                   interests.

         For purposes of this definition:

              -    whether a person is a beneficial owner will be determined in
                   accordance with Rule 13d-3 under the Exchange Act;

              -    a person includes any syndicate or group that would be deemed
                   to be a person under Section 13(d)(3) of the Exchange Act;
                   and

              -    we may rely on 13D and 13G filings filed pursuant to the
                   Exchange Act.

         A "termination of trading" will be deemed to have occurred if our
common stock or other common stock into which the notes are convertible is
neither listed for trading on a U.S. national securities exchange nor approved
for listing on Nasdaq or any similar U.S. system of automated dissemination of
quotations of securities prices, and no American Depository Shares or similar
instruments for such common stock are so listed or approved for listing in the
U.S.

         We will comply with any applicable provisions of Rule 13e-4 and any
other applicable tender offer rules under the Exchange Act in the event of a
designated event.

         These designated event repurchase rights could discourage a potential
acquirer of EPIX. However, this designated event repurchase feature is not the
result of management's knowledge of any specific effort to obtain control of us
by means of a merger, tender offer or solicitation, or part of a plan by
management to adopt a series of anti-takeover

                                       33


provisions. The term "designated event" is limited to specified transactions and
may not include other events that might adversely affect our financial condition
or business operations. Our obligation to offer to repurchase the notes upon a
designated event would not necessarily afford you protection in the event of a
highly leveraged transaction, reorganization, merger or similar transaction
involving us. No notes may be repurchased by us at the option of holders upon a
designated event if the principal amount of the notes has been accelerated and
such acceleration has not been rescinded.

         We may be unable to repurchase the notes in the event of a designated
event. If a designated event were to occur, we may not have enough funds to pay
the repurchase price for all tendered notes. Any future credit or financing
agreements or other agreements relating to our indebtedness may contain
provisions prohibiting repurchase of the notes under certain circumstances, or
expressly prohibit our repurchase of the notes upon a designated event or may
provide that a designated event constitutes an event of default under that
agreement. The subordination provisions of the indenture may also preclude us
from repurchasing the notes. If a designated event occurs at a time when we are
prohibited from repurchasing notes, we could seek the consent of our lenders to
repurchase the notes or attempt to refinance this debt. If we do not obtain
consent, we would not be permitted to repurchase the notes. Our failure to
repurchase tendered notes would constitute an event of default under the
indenture, which might constitute a default under the terms of our other
indebtedness.

         The definition of change in control includes a phrase relating to the
conveyance, transfer, sale, lease or disposition of all or substantially all of
our assets. There is no precise, established definition of the phrase
"substantially all" under applicable law. Accordingly, your ability to require
us to repurchase your notes as a result of conveyance, transfer, sale, lease or
other disposition of less than all of our assets may be uncertain.

         Before we repurchase the notes in whole or in part, we will be required
to repay the then outstanding principal amount, together with accrued unpaid
interest, under our Schering AG loan facility.

         RANKING

         The notes will:

         -    be our senior unsecured obligations;

         -    be subordinated in right of payment with all of our existing and
              future indebtedness under our Schering AG loan facility;

         -    rank on parity in right of payment with all of our existing and
              future senior debt, other than our Schering AG loan facility; and

         -    rank senior in right of payment to all of our future debt that is
              subordinated to the notes.

         The notes are effectively subordinated in right of payment to our 
existing and future secured debt, to the extent of such security, and to all 
existing and future indebtedness (including trade payables) of any 
subsidiaries that we may create in the future. As a result of the 
subordination of the notes to the Schering AG loan facility, in the event of 
our bankruptcy, dissolution or reorganization, holders of the notes may 
receive less, ratably, than our other creditors, including without limitation 
our trade creditors and other creditors that are not contractually 
subordinated to the Schering AG loan facility. The indenture does not limit 
our ability to incur debt, including secured debt, or the amount of 
indebtedness or other liabilities our subsidiaries may incur. Our ability to 
make required interest, principal, repurchase or redemption payments on the 
notes may be impaired as a result of the obligations of any of our future 
subsidiaries. Our subsidiaries, if any, will be separate and distinct legal 
entities and have no obligation, contingent or otherwise, to pay any amounts 
due pursuant to the notes or to make any funds available therefor, whether by 
dividends, loans or other payments. Any right we have to receive assets of 
any of our future subsidiaries upon that subsidiary's liquidation or 
reorganization (and the consequent right of the holders of the notes to 
participate in those assets) will be effectively subordinated to the claims 
of that subsidiary's creditors, except to the extent that we are ourselves 
recognized as a creditor of that subsidiary, in which case our claims would 
still be subordinate to any security interests in the assets of that 
subsidiary and any indebtedness of that subsidiary senior to that held by us. 
At September 30, 2004, the outstanding principal amount of our indebtedness 
under our Schering AG loan facility was $15 million, which amount was repaid 
in full in October 2004, and we did not have any other

                                       34


secured debt outstanding. No payment will be able to be made in respect of the
notes if the indebtedness under the Schering AG loan facility is not paid when
due or any other default under the Schering AG loan facility occurs and the
maturity of such indebtedness is accelerated in accordance with its terms.
Furthermore, if certain other defaults exist with respect to the Schering AG
loan facility, the holders of such indebtedness will be able to prevent payments
on the notes for specified periods of time. In addition, before we redeem or
repurchase for cash the notes in whole or in part, we will be required to repay
the then outstanding principal amount, together with accrued and unpaid
interest, under our Schering AG loan facility, other than a redemption by us of
less than $7.5 million cumulative principal amount of the notes.

         We are obligated to pay reasonable compensation to the trustee and to
indemnify the trustee against certain losses, liabilities or expenses incurred
by it in connection with its duties relating to the notes. The trustee's claims
for such payments will be senior to those of holders of the notes in respect of
all funds collected or held by the trustee.

         MERGER AND SALE OF ASSETS BY EPIX

         The indenture provides that we may not consolidate with or merge with
or into any other person or convey, transfer or lease all or substantially all
of our properties or assets to another person, unless among other things:

         -    we are the surviving person, or the resulting, surviving or
              transferee person, if other than us, is organized and existing
              under the laws of the United States, any state thereof or the
              District of Columbia;

         -    the successor person, if other than us, assumes, by supplemental
              indenture satisfactory in form to the trustee, all of our
              obligations under the notes and the indenture;

         -    after giving effect to such transaction, there is no event of
              default under the indenture, and no event which, after notice or
              passage of time or both, would become an event of default; and

         -    we have delivered to the trustee an officers' certificate stating
              that such transaction complies with these requirements and an
              opinion of counsel as to the first two items above.

         When such a person assumes our obligations in such circumstances,
subject to certain exceptions, we shall be discharged from all obligations under
the notes and the indenture.

         EVENTS OF DEFAULT; NOTICE AND WAIVER

         The following will be events of default with respect to the notes under
the indenture:

         -    we fail to pay principal when due at maturity, upon redemption,
              repurchase or otherwise on the notes;

         -    we fail to pay any interest or additional interest, if any, on the
              notes, when due and such failure continues for a period of 30
              consecutive days;

         -    we fail to perform or observe any of the covenants in the
              indenture for 60 consecutive days after written notice to us from
              the trustee (or to us and the trustee from the holders of at least
              25% in principal amount of the outstanding notes);

         -    payment defaults, continuing after any applicable grace periods,
              or acceleration of indebtedness (if such acceleration is not
              withdrawn, cancelled or otherwise annulled within 10 days), where
              the aggregate amount of defaulted or accelerated principal,
              premium and interest is in excess of $10 million; or

         -    certain events involving our bankruptcy, insolvency or
              reorganization.

         The trustee may withhold notice to the holders of the notes of any
default, except defaults in payment of principal, interest or additional
interest, if any, on the notes. However, the trustee must consider it to be in
the interest of the holders of the notes to withhold this notice.

                                       35


         If an event of default occurs and continues, the trustee or the holders
of at least 25% in principal amount of the notes then outstanding may declare
the principal and accrued interest and additional interest, if any, on the
outstanding notes to be immediately due and payable. In case of certain events
of bankruptcy or insolvency involving us, the principal and accrued interest and
additional interest, if any, on the notes will automatically become due and
payable. However, with certain exceptions, if we cure all defaults, except the
nonpayment of principal, interest or additional interest, if any, that became
due as a result of the acceleration, and meet certain other conditions and the
holders of a majority of the principal amount of outstanding notes waive these
past defaults on behalf of all holders of the notes, this declaration may be
cancelled.

         Payments of principal, interest or additional interest, if any, on the
notes that are not made when due will accrue interest from the required payment
date at the annual rate of 1% above the then applicable interest rate for the
notes.

         The holders of a majority of outstanding notes will have the right to
direct the time, method and place of any proceedings for any remedy available to
the trustee, subject to limitations specified in the indenture.

         No holder of the notes may pursue any remedy under the indenture,
except in the case of a default in the payment of principal, interest or
additional interest, if any, unless:

         -    the holder has given the trustee written notice of an event of
              default;

         -    the holders of at least 25% in principal amount of the notes then
              outstanding make a written request to the trustee to pursue the
              remedy;

         -    the holder or holders have offered reasonable security or
              indemnity to the trustee against any costs, liability or expense
              of the trustee;

         -    the trustee does not receive an inconsistent direction from the
              holders of a majority in principal amount of the notes; and

         -    the trustee fails to comply with the request within 60 days after
              receipt of the request and offer of indemnity.

         MODIFICATION AND WAIVER

         The consent of the holders of a majority in principal amount of the
outstanding notes is required to modify or amend the indenture. However, a
modification or amendment requires the consent of the holder of each outstanding
note if it would:

         -    extend the fixed maturity of any note;

         -    reduce the rate or extend the time for payment of interest or
              additional interest, if any, of any note;

         -    reduce the principal amount of any note;

         -    reduce any amount payable upon redemption or repurchase of any
              note;

         -    after the occurrence of a designated event, adversely change our
              obligation to repurchase any note upon a designated event;

         -    impair the right of a holder to institute suit for payment on any
              note;

         -    change the currency in which any note is payable;

         -    impair the right of a holder to convert any note or reduce the
              number of shares of common stock or the amount of any other
              property receivable upon conversion;

         -    reduce the quorum or voting requirements under the indenture; or

                                       36


         -    subject to specified exceptions, modify certain provisions of the
              indenture relating to modification or waiver of provisions of the
              indenture.

         In addition, a modification or amendment that would, prior to the
occurrence of a designated event, adversely change our obligation to repurchase
any note upon a designated event requires the consent of the holders of
two-thirds in principal amount of the outstanding notes.

         We are permitted to modify certain provisions of the indenture without
the consent of the holders of the notes.

         FORM, DENOMINATION AND REGISTRATION

The notes have been issued:

         -    in fully registered form;

         -    without interest coupons; and

         -    in denominations of $1,000 principal amount and integral multiples
              of $1,000.

         GLOBAL NOTE, BOOK-ENTRY FORM

         Notes are evidenced by one or more global notes. We have deposited the
global note or notes with DTC and have registered the global notes in the name
of Cede & Co. as DTC's nominee. Except as set forth below, a global note may be
transferred, in whole or in part, only to another nominee of DTC or to a
successor of DTC or its nominee.

         Beneficial interests in a global note may be held directly through DTC
if such holder is a participant in DTC, or indirectly through organizations that
are participants in DTC (called "participants"). Transfers between participants
will be effected in the ordinary way in accordance with DTC rules and will be
settled in clearing house funds. The laws of some states require that certain
persons take physical delivery of securities in definitive form. As a result,
the ability to transfer beneficial interests in the global note to such persons
may be limited.

         Holders who are not participants may beneficially own interests in a
global note held by DTC only through participants, or certain banks, brokers,
dealers, trust companies and other parties that clear through or maintain a
custodial relationship with a participant, either directly or indirectly (called
"indirect participants"). So long as Cede & Co., as the nominee of DTC, is the
registered owner of a global note, Cede & Co. for all purposes will be
considered the sole holder of such global note. Except as provided below, owners
of beneficial interests in a global note will:

         -    not be entitled to have certificates registered in their names;
              and

         -    not be considered holders of the global note (other than in an
              enforcement by such owner of a beneficial interest to exchange
              such beneficial interest for notes in certificated form).

         We will pay interest, and additional interest, if any, and the
redemption price and the repurchase price of a global note to Cede & Co., as the
registered owner of the global note, by wire transfer of immediately available
funds on each interest payment date or the redemption or repurchase date, as the
case may be. Neither we, the trustee nor any paying agent will be responsible or
liable:

         -    for the records relating to, or payments made on account of,
              beneficial ownership interests in a global note; or

         -    for maintaining, supervising or reviewing any records relating to
              the beneficial ownership interests.

         Neither we, the trustee, registrar, paying agent nor conversion agent
will have any responsibility for the performance by DTC or its participants or
indirect participants of their respective obligations under the rules and
procedures governing their operations. DTC has advised us that it will take any
action permitted to be taken by a holder of notes, including the presentation of
notes for exchange, only at the direction of one or more participants to whose
account with DTC interests in the global note are credited, and only in respect
of the principal amount of the notes

                                       37


represented by the global note as to which the participant or participants has
or have given such direction. DTC has advised us that it is:

         -    a limited purpose trust company organized under the laws of the
              State of New York, and a member of the Federal Reserve System;

         -    a "clearing corporation" within the meaning of the Uniform
              Commercial Code; and

         -    a "clearing agency" registered pursuant to the provisions of
              Section 17A of the Exchange Act.

         DTC was created to hold securities for its participants and to
facilitate the clearance and settlement of securities transactions between
participants through electronic book-entry changes to the accounts of its
participants. Participants include securities brokers, dealers, banks, trust
companies and clearing corporations and other organizations. Some of the
participants or their representatives, together with other entities, own DTC.
Indirect access to the DTC system is available to others such as banks, brokers,
dealers and trust companies that clear through or maintain a custodial
relationship with a participant, either directly or indirectly.

         DTC has agreed to the foregoing procedures to facilitate transfers of
interests in a global note among participants. However, DTC is under no
obligation to perform or continue to perform these procedures, and may
discontinue these procedures at any time.

         We will issue the notes in definitive certificated form if DTC notifies
us that it is unwilling or unable to continue as depositary or DTC ceases to be
a clearing agency registered under the Exchange Act and a successor depositary
is not appointed by us within 90 days. In addition, beneficial interests in a
global note may be exchanged for definitive certificated notes upon request by
or on behalf of DTC in accordance with customary procedures. We may determine at
any time and in our sole discretion that notes shall no longer be represented by
global notes, in which case we will issue certificates in definitive form in
exchange for the global notes.

         REGISTRATION RIGHTS OF THE NOTEHOLDERS

         We have entered into a registration rights agreement with the initial
purchasers. We have filed a shelf registration statement with the SEC, of which
this prospectus is a part, covering resale of the registrable securities. We
will use our reasonable best efforts to keep the shelf registration statement
effective until the date there are no longer any registrable securities.

         When we use the term "registrable securities" in this section, we are
referring to the notes and the common stock issuable upon conversion of the
notes until the earliest of:

         -    the effective registration under the Securities Act and the resale
              of the registrable securities in accordance with the registration
              statement;

         -    the expiration of the holding period for non-affiliates with
              respect to the registrable securities under Rule 144(k) under the
              Securities Act;

         -    the sale of the registrable securities pursuant to Rule 144 under
              the Securities Act;

         -    the registrable securities cease to be outstanding; and

         -    June 7, 2006.

         We may suspend the use of the prospectus included in the registration
statement under certain circumstances relating to pending corporate
developments, public filings with the SEC and similar events. Any suspension
period shall not exceed:

         -    30 days in any three-month period; or

                                       38


         -    an aggregate of 90 days for all suspension periods in any 12-month
              period.

         Notwithstanding the foregoing, we will be permitted to suspend the use
of the prospectus included in the shelf registration statement for up to 60 days
in any three-month period under certain circumstances, relating to possible
acquisitions, financings or other similar transactions.

         We will pay additional interest on the interest payment dates for the
notes to the initial purchasers in the event the prospectus included in the
registration statement is unavailable for periods in excess of those permitted
above. Those additional amounts will accrue until such unavailability is cured:

         -    in respect of any notes at a rate per year equal to 0.25% of the
              outstanding principal amount thereof for the first 90 days after
              the occurrence of the event and 0.50% of the outstanding principal
              amount thereof after the first 90 days; and

         -    in respect of shares of common stock into which the notes have
              been converted at a rate per year equal to 0.25% of the
              then-applicable conversion price for the first 90 days after the
              occurrence of the event and 0.50% of the then-applicable
              conversion price after the first 90 days.

         We will have no other liabilities for monetary damages with respect to
our registration obligations.

         A holder who elects to sell registrable securities pursuant to the
shelf registration statement will be required to:

         -    be named as a selling holder in the related prospectus;

         -    deliver a prospectus to purchasers; and

         -    be subject to the provisions of the registration rights agreement,
              including indemnification provisions.

         Under the registration rights agreement we will:

         -    pay all expenses of the shelf registration statement;

         -    provide each registered holder copies of the prospectus;

         -    notify holders when the shelf registration statement has become
              effective; and

         -    take other reasonable actions as are required to permit
              unrestricted resales of the registrable securities in accordance
              with the terms and conditions of the registration rights
              agreement.

         The plan of distribution of the shelf registration statement will
permit resales of registrable securities by selling holders through brokers and
dealers. See "Plan of Distribution."

         INFORMATION CONCERNING THE TRUSTEE

         We have appointed U.S. Bank National Association, the trustee under the
indenture, as paying agent, conversion agent, note registrar and custodian for
the notes. The trustee or its affiliates may provide banking and other services
to us in the ordinary course of their business. Subject to certain conditions,
we have the right to replace the trustee.

         The indenture contains certain limitations on the rights of the
trustee, if it or any of its affiliates is then our creditor, to obtain payment
of claims in certain cases or to realize on certain property received on any
claim as security or otherwise. The trustee and its affiliates will be permitted
to engage in other transactions with us. However, if the trustee or any
affiliate continues to have any conflicting interest and a default occurs with
respect to the notes, the trustee must eliminate such conflict or resign.

         GOVERNING LAW

         The notes and the indenture are governed by, and shall be construed in
accordance with, the laws of the State of New York.

                                       39


                          DESCRIPTION OF CAPITAL STOCK

         Our authorized capital stock consists of 40,000,000 shares of common 
stock and 1,000,000 shares of preferred stock, par value $.01 per share. As 
of September 30, 2004, we had 23,089,499 shares of common stock outstanding 
and no shares of preferred stock outstanding.

         COMMON STOCK

         The holders of our common stock are entitled to one vote for each 
share held of record on all matters voted upon by our stockholders and may 
not cumulate votes. Subject to the rights of holders of any future series of 
undesignated preferred stock which may be designated, each share of the 
outstanding common stock is entitled to participate ratably in any 
distribution of net assets made to the stockholders in the liquidation, 
dissolution or winding up of our company and is entitled to participate 
equally in dividends if and when declared by our board of directors. There 
are no redemption, sinking fund, conversion or preemptive rights with respect 
to shares of our common stock. All shares of our common stock have equal 
rights and preferences.

         PREFERRED STOCK

         Our board of directors has the authority, without further stockholder
approval, to issue 1,000,000 shares of preferred stock where defined in one or
more series and to fix the relative rights, preferences, privileges,
qualifications, limitations and restrictions of such preferred stock, including
dividend rights, dividend rates, conversion rights, voting rights, terms of
redemption, redemption prices, liquidation preferences, sinking fund terms and
the number of shares constituting any series or the designation of such series.
The issuance of preferred stock, while potentially providing desirable
flexibility in connection with possible acquisitions and other corporate
purposes, could have the effect of delaying, deferring or preventing a change in
control of our company, which may discourage bids for our common stock at a
premium over the market price of the common stock and may adversely affect the
market price of, and the voting and other rights of the holders of, our common
stock. We have no present plans to issue any shares of preferred stock.

                                       40


                 CERTAIN U.S. FEDERAL INCOME TAX CONSIDERATIONS

         The following discussion is a summary of certain U.S. federal income
tax considerations of the purchase, ownership and disposition of the notes and
of our common stock into which the notes may be converted. This discussion
assumes that the notes will be treated as indebtedness for U.S. federal income
tax purposes.

         This discussion applies to holders that will hold the notes and common
stock as "capital assets" within the meaning of Section 1221 of the Internal
Revenue Code of 1986, as amended, which we sometimes refer to as the Code, and
does not address tax considerations applicable to investors in light of their
particular circumstances or to investors that may be subject to special tax
rules, such as financial institutions, mutual funds, tax-exempt organizations,
insurance companies, dealers in securities or currencies, traders in securities
who elect to apply mark-to-market method of accounting, persons that will hold
notes as a position in a hedging transaction, "straddle" or "conversion
transaction" for tax purposes, persons subject to the alternative minimum tax,
certain former citizens or residents of the United States, United States Holders
(as defined below) whose functional currency is not the U.S. dollar or persons
deemed to sell notes under the constructive sale provisions of the Code.

         This summary is based on the Code, administrative pronouncements,
judicial decisions and final, temporary and proposed Treasury regulations,
changes to any of which subsequent to the date of this prospectus may affect the
tax consequences described herein, possibly with retroactive effect. We have not
sought a ruling from the Internal Revenue Service with respect to the statements
made and the conclusions reached in the following summary, and there can be no
assurance that the Internal Revenue Service will agree with such statements and
conclusions.

         Persons considering the purchase of the notes are urged to consult
their tax advisers with regard to the application of the U.S. federal income tax
laws to their particular situations as well as any tax consequences arising
under the U.S. federal estate or gift tax laws or the laws of any state, local
or foreign taxing jurisdiction.

TAX CONSEQUENCES TO UNITED STATES HOLDERS

         As used herein, the term "United States Holder" means a beneficial
owner of a note or shares of our common stock that is, as determined for U.S.
federal income tax purposes, either (1) a citizen or resident of the United
States, or U.S.; (2) a corporation, or other entity taxable as a corporation for
U.S. federal income tax purposes, formed under the laws of the U.S. or a state
of the U.S.; (3) an estate the income of which is subject to U.S. federal income
tax regardless of its source; or (4) a trust subject to the primary supervision
of a court within the U.S. which has one or more U.S. persons with authority to
control all substantive decisions, or which has a valid election in effect under
applicable Treasury Regulations to be treated as a U.S. person. A "Non-United
States Holder" is any holder other than a United States Holder.

         If a partnership (including for this purpose any entity, foreign or
domestic, classified as a partnership for U.S. federal income tax purposes) is a
beneficial owner of the notes or the common stock into which the notes may be
converted, the U.S. federal income tax treatment of a partner in the partnership
generally will depend on the status of the partner and the activities of the
partnership. As a general matter, income earned by a foreign or domestic
partnership is attributed to its owners for U.S. federal income tax purposes. A
holder of the notes or the common stock that is a partnership, and the partners
in such partnership, should consult their individual tax advisors regarding the
federal, state, local and foreign tax consequences of the purchase, ownership
and disposition of the notes (and the common stock).

TAXATION OF INTEREST

         Interest paid on the notes will be included in the income of a holder
as ordinary income at the time it is treated as received or accrued, in
accordance with the holder's regular method of tax accounting.

         In general, if the terms of a debt instrument entitle a holder to
receive payments other than fixed periodic interest that exceed the issue price
of the instrument, the holder may be required to recognize additional interest
as "original issue discount" over the term of the instrument. Further, if the
amount or timing of any additional payments on a note is contingent, the note
could be subject to special rules that apply to contingent debt instruments.
These rules generally require a holder to accrue interest income at a rate
higher than the stated interest rate on the note and to treat as ordinary

                                       41


income, rather than capital gain, any gain recognized on a sale, exchange or
retirement of a note before the resolution of the contingencies.

         If the notes are not registered with the SEC within prescribed time
periods or in certain other circumstances described above under "Description of
the Notes - Registration Rights of the Noteholders", the initial purchasers of
the notes will be entitled to additional interest. Also, under certain
circumstances, we may allow noteholders to participate in extraordinary
distributions to our stockholders that would otherwise cause the notes to become
convertible, as described above under "Description of the Notes-- Conversion of
Notes." Any such extraordinary distributions received by noteholders would
likely be treated as additional interest on the notes. In addition, in certain
circumstances, we may pay the repurchase price of the notes in shares of our
common stock or a combination of cash and shares of our common stock, as
described above under "Description of the Notes--Repurchase at the Option of the
Holder upon a Designated Event," in which case holders of the notes will be
entitled to receive a premium.

         Notwithstanding the possibility of such contingent payments, under
applicable Treasury Regulations, payments on a note that are subject to either a
remote or incidental contingency may be ignored. We believe that the prospect of
the foregoing payments being made should be considered as a remote and/or
incidental contingency so that the payments should be ignored.

         Therefore, for purposes of filing tax or information returns with the
Internal Revenue Service, we will not treat the notes as contingent payment debt
instruments. Our determination that the notes are not contingent payment debt
instruments is binding on each holder unless the holder explicitly discloses in
the manner required by applicable Treasury Regulations that its determination is
different from ours. Our determination is not, however, binding on the Internal
Revenue Service. This discussion assumes that the notes are not subject to the
contingent payment debt instrument rules.

MARKET DISCOUNT

         A United States Holder who buys a note for less than its stated
redemption price at maturity may be considered to have purchased the note at a
"market discount." If the market discount is less than 0.25% of the stated
redemption price of the note at maturity multiplied by the number of complete
years to maturity, then the market discount will be deemed to be zero.

         A United States Holder may elect to include market discount in income
currently as it accrues. Any such election will apply to all market discount
bonds acquired during or after the year for which the election is made, and the
election may be terminated only with the consent of the Internal Revenue
Service.

         If a United States Holder does not make an election to include market
discount in income currently as it accrues, any principal amount received or
gain recognized by a United States Holder on the sale, exchange, retirement or
other taxable disposition of a note will be treated as ordinary income to the
extent of any accrued market discount on the note not previously included in
income. Unless a United States Holder irrevocably elects to accrue market
discount under a constant-interest method, accrued market discount is the total
market discount multiplied by a fraction, the numerator of which is the number
of days the United States Holder has held the note and the denominator of which
is the number of days from the date the holder acquired the note until its
maturity. If a United States Holder exchanges or converts a note into common
stock in a transaction that is otherwise tax free, any accrued market discount
on the note not previously included in income will carry over to the common
stock, and generally any gain recognized upon the disposition of such common
stock will be treated as ordinary income to the extent of such accrued market
discount.

         A United States Holder may be required to defer a portion of such
holder's interest deductions for the taxable year attributable to any
indebtedness incurred or continued to purchase or carry a note purchased with
market discount. Any such deferred interest expense may not exceed the market
discount that accrues during a taxable year and is, in general, allowed as a
deduction not later than the year in which the market discount is includible in
income. This interest expense deferral will not apply if a United States Holder
makes an election to include market discount in income currently as it accrues.


                                       42


MARKET PREMIUM

         A United States Holder who buys a note for more than its stated
redemption price at maturity generally will be considered to have purchased the
note at a "market premium." Market premium, however, does not include any
premium attributable to the conversion feature of the note. If an election is
made, the market premium may generally be amortized using a constant yield
method, over the remaining term of the note.

         Interest otherwise required to be included in income with respect to
the note during any tax year may be offset by the amount of any amortized market
premium for the year. An election to amortize market premium will apply to all
market premium bonds acquired during or after the year for which the election is
made, and the election may be terminated only with the consent of the Internal
Revenue Service.

SALE, EXCHANGE, REPURCHASE, REDEMPTION OR RETIREMENT OF NOTES

         Upon a sale, exchange, repurchase, redemption or retirement of a note
(other than a conversion into shares of our common stock or repurchase for
shares of our common stock or a combination of shares of our common stock and
cash), a United States Holder will generally recognize taxable gain or loss
equal to the difference between (1) the amount realized on the sale, exchange,
repurchase, redemption or retirement (except to the extent such amount is
attributable to accrued interest not previously included in income, which will
be taxable as interest income as discussed above under "Tax Consequences to
United States Holders--Taxation of Interest") and (2) such United States
Holder's adjusted tax basis in the note.

         A United States Holder's adjusted tax basis in a note will be, in
general, the cost of the note to the holder, increased by the amount of any
accrued but unpaid interest previously included in the holder's taxable income
and any accrued market discount previously included in the holder's income and
decreased by any principal payments received and any amortizable market premium
accrued.

         Subject to the discussion above regarding market discount, gain or loss
recognized on the sale, exchange, repurchase, redemption or retirement of a note
generally will be capital gain or loss and will be long-term capital gain or
loss if at the time of the sale, exchange, repurchase, redemption or retirement
the note has been held for more than one year. The deductibility of capital
losses is subject to limitations.

CONVERSION OF NOTES INTO COMMON STOCK

         A United States Holder's conversion of a note into shares of our common
stock generally will not be a taxable event, except (i) the receipt of shares
attributable to accrued interest not previously included in income will be
taxable as interest income as discussed above under "Tax Consequences to United
States Holders--Taxation of Interest," and (ii) the receipt of cash in lieu of a
fractional share of our common stock will result in capital gain or loss
(measured by the difference between the cash received in lieu of the fractional
share and the United States Holder's tax basis attributable to the fractional
share), except that any gain will be treated as ordinary income to the extent of
accrued market discount allocable to such share as discussed above.

         A United States Holder's tax basis in the shares of our common stock
received upon a conversion of a note (except for any shares received
attributable to accrued interest not previously included in income) will be the
same as the United States Holder's tax basis in the note at the time of the
conversion, reduced by any basis attributable to a fractional share. The United
States Holder's holding period for the shares of our common stock received
(except for any shares received attributable to accrued interest not previously
included in income) will include the holding period of the note converted.

         A United States Holder's tax basis in any shares received attributable
to accrued interest not previously included in income will equal the fair market
value of the shares at the time of the conversion, and the United States
Holder's holding period for such shares will begin on the day after the
conversion.

REPURCHASE OF NOTES FOR COMMON STOCK OR COMBINATION OF CASH AND COMMON STOCK

         In certain circumstances, we may pay the repurchase price of the notes
in shares of our common stock or a combination of cash and shares of our common
stock, as described above under "Description of the Notes--Repurchase at the
Option of the Holder upon a Designated Event." If a United States Holder
requires us to repurchase some or all of the

                                       43


holder's notes and we elect to pay the repurchase price in shares of our common
stock or a combination of cash and shares of our common stock, the repurchase
should qualify as a recapitalization for U.S. federal income tax purposes if the
notes qualify as "securities" for tax purposes. Although the determination of
the notes as "securities" is not free from doubt, the notes should qualify as
"securities." United States Holders should consult their own tax advisors
regarding this determination.

         If the repurchase price is paid solely in shares of our common stock
(except for cash received in lieu of a fractional share), and the repurchase
qualifies as a recapitalization, the repurchase will result in the same tax
consequences as a conversion of the notes into shares of our common stock, as
described above under "Tax Consequences to United States Holders-Conversion of
Notes into Common Stock."

         If the repurchase price is paid in a combination of cash (other than
cash received in lieu of a fractional share) and shares of our common stock, and
the repurchase qualifies as a recapitalization, a United States Holder should
recognize gain, but not loss, equal to the lesser of (i) the sum of the fair
market value of the shares of our common stock received and the amount of cash
received less the holder's adjusted tax basis in the notes and (ii) the amount
of cash received. If the repurchase does not have the effect of a distribution
of a dividend, subject to the discussion above regarding market discount, such
gain will be capital gain. For purposes of the foregoing, any cash or shares
received attributable to accrued interest not previously included in income and
any cash received in lieu of a fractional share will not be taken into account.
The receipt of cash or shares attributable to accrued interest not previously
included in income will be taxable as interest income as discussed above under
"Tax Consequences to United States Holders--Taxation of Interest," and the
receipt of cash in lieu of a fractional share of our common stock will result in
capital gain or loss (measured by the difference between the cash received in
lieu of the fractional share and the United States Holder's tax basis
attributable to the fractional share), except that any gain will be treated as
ordinary income to the extent of accrued market discount allocable to such share
as discussed above.

         The United States Holder's tax basis in the shares of our common stock
received (except for any shares received attributable to accrued interest not
previously included in income) should be the same as the United States Holder's
tax basis in the notes repurchased, less the amount of the basis attributable to
a fractional share and the amount of cash received (except (i) to the extent any
cash received is attributable to accrued interest not previously included in
income and (ii) for cash received in lieu of a fractional share), and increased
by the amount of gain recognized (other than gain with respect to a fractional
share). The United States Holder's holding period for the shares of common stock
received (except for any shares received attributable to accrued interest not
previously included in income) will include the holding period of the notes
repurchased. A United States Holder's tax basis in any shares received
attributable to accrued interest not previously included in income would equal
the fair market value of the shares at the time of the repurchase, and the
United States Holder's holding period for such shares would begin on the day
after the repurchase.

         If the repurchase of notes for shares of our common stock or a
combination of cash and shares of our common stock does not qualify as a
recapitalization (or as an otherwise nontaxable transaction), a United States
Holder would recognize gain or loss as discussed above under "Tax Consequences
to United States Holders--Sale, Exchange, Repurchase, Redemption or Retirement
of Notes."

CONSTRUCTIVE DISTRIBUTIONS

         If at any time we increase the conversion rate of the notes, either at
our discretion or pursuant to the anti-dilution provisions of the indenture, the
increase may be deemed to be the payment of a taxable dividend to the United
States Holders of the notes. Generally, an increase in the conversion rate in
the event of a cash dividend to our stockholders will result in a deemed
distribution to the United States Holders of the notes, but generally a
reasonable increase in the conversion rate in the event of stock dividends or
distributions of rights to our stockholders to subscribe for shares of our
common stock will not result in a deemed distribution to the United States
Holders of the notes. In certain circumstances, the failure to adjust the
conversion rate may result in a deemed distribution to the holders of our common
stock. Deemed distributions will be taxed in the manner described below under
"Tax Consequences to United States Holders--Taxation of Distributions on Common
Stock."


                                       44


TAXATION OF DISTRIBUTIONS ON COMMON STOCK

         Distributions, if any, paid with respect to shares of our common stock
after a conversion, other than certain pro rata distributions of common shares,
will be treated as dividends to the extent paid out of current or accumulated
earnings and profits (as determined under U.S. federal income tax principles)
and will be includible in income by the United States Holder. If a distribution
exceeds our current and accumulated earnings and profits, the excess will be
first treated as a tax-free return of the United States Holder's investment, up
to the United States Holder's tax basis in the shares of common stock. Any
remaining excess will be treated as capital gain. Dividends received by certain
noncorporate United States Holders on shares of common stock may be subject to
U.S. federal income tax at lower rates than other types of ordinary income if
certain holding period requirements and other conditions are met. United States
Holders should consult their own tax advisers regarding the applicability of
such reduced tax rates in their particular circumstances.

CERTAIN PAYMENTS ON COMMON STOCK

         If we fail to comply with our obligations under "Description of
Notes--Registration Rights of the Noteholders," we may be required to make
payments to noteholders who have converted their notes into shares of common
stock. The tax treatment of any such payments for U.S. federal income tax
purposes is unclear. However, any such payment would most likely constitute
ordinary income to a stockholder at the time it is accrued or received in
accordance with the holder's regular method of tax accounting. Those payments
likely would not qualify for the reduced rate of tax applicable to dividends as
described above.

SALE OR OTHER DISPOSITION OF COMMON STOCK

         Unless a nonrecognition provision applies, subject to the discussion
above regarding market discount, gain or loss realized by a United States Holder
on the sale or other disposition of shares of our common stock received upon
conversion of a note will be recognized as capital gain or loss for U.S. federal
income tax purposes, and will be long-term capital gain or loss if the United
States Holder held the shares of common stock for more than one year. The amount
of the United States Holder's gain or loss will be equal to the difference
between the United States Holder's tax basis in the shares of common stock
disposed of and the amount realized on the disposition.

TAX CONSEQUENCES TO NON-UNITED STATES HOLDERS

         As used herein, the term "Non-United States Holder" means a beneficial
owner of a note or shares of our common stock that is not a United States
Holder, as defined above.

TAXATION OF INTEREST

         Subject to the discussion below regarding backup withholding, interest
income on the notes paid to a Non-United States Holder will be exempt from U.S.
federal income and withholding tax, provided that:

         -    the Non-United States Holder does not own, actually or
              constructively, 10% or more of the total combined voting power of
              all classes of our stock entitled to vote and is not a controlled
              foreign corporation related, directly or indirectly, to us through
              stock ownership and is not a bank receiving certain types of
              interest,

         -    the certification requirement described below has been fulfilled
              with respect to the Non-United States Holder, and

         -    such interest is not effectively connected with the conduct by
              such Non-United States Holder of a trade or business in the United
              States.

         The certification requirement referred to above will be fulfilled if
the beneficial owner of a note certifies on IRS Form W-8BEN, under penalties of
perjury, that it is not a U.S. person and provides its name and address.

         Interest income on the notes that is not exempt from U.S. federal
income and withholding tax generally will be subject to U.S. withholding tax at
a 30% rate, subject to reduction by an applicable treaty, unless such income is
effectively connected income as described below in "Tax Consequences to
Non-United States Holders--Effectively Connected Income."

                                       45


         Additional interest received by an initial purchaser that is a
Non-United States Holder if the notes are not registered with the SEC within
prescribed time periods or in certain other circumstances described above in
"Description of the Notes--Registration Rights of the Noteholders" and any
extraordinary distributions received by Non-United States Holders of the notes
as described above under "Description of the Notes--Conversion of Notes" may
not be exempt from U.S. withholding tax as described above. Holders should
consult with their own tax advisers regarding such determination.

SALE, EXCHANGE OR OTHER DISPOSITION OF NOTES OR COMMON STOCK

         Subject to the discussion below regarding backup withholding, a
Non-United States Holder generally will not be subject to U.S. federal income
and withholding tax on gain realized on a sale, exchange or other disposition
(other than a conversion into shares of our common stock, which is described
below) of the notes or of shares of our common stock, unless:

         -    the gain is effectively connected with the conduct by such
              Non-United States Holder of a trade or business in the United
              States,

         -    in the case of a Non-United States Holder who is a nonresident
              alien individual, the individual is present in the United States
              for 183 or more days in the taxable year of the sale, exchange or
              disposition and certain other conditions are met, or

         -    we are or have been a U.S. real property holding corporation at
              any time within the shorter of the five year period preceding such
              sale, exchange or disposition and the period the Non-United States
              Holder held the notes or common stock. We believe that we are not,
              and do not anticipate becoming, a U.S. real property holding
              corporation for U.S. federal income tax purposes.

         Any gain realized on a sale, exchange or other disposition of the notes
taxed as interest income will be subject to the rules described above regarding
taxation of interest.

CONVERSION OF NOTES INTO COMMON STOCK

         Non-United States Holders generally will not be subject to U.S. federal
income and withholding tax on the conversion of a note into shares of our common
stock. However, any gain recognized by a Non-United States Holder on the
conversion of a note into shares of our common stock due to the receipt of cash
in lieu of a fractional share will be subject to the rules described above
regarding the sale, exchange or other disposition of a note, and any shares
taxable as interest income will be subject to the rules described above
regarding taxation of interest.

DISTRIBUTIONS ON NOTES AND COMMON STOCK

         If a Non-United States Holder of a note were deemed to have received a
constructive dividend (see "Tax Consequences to United States
Holders-Constructive Distributions" above), the Non-United States Holder
generally will be subject to U.S. withholding tax at a 30% rate, subject to
reduction by an applicable treaty, on the taxable amount of the dividend unless
such income is effectively connected income as described below in "Tax
Consequences to Non-United States Holders-Effectively Connected Income." In
addition, dividends paid to a Non-United States Holder of our common stock
generally will be subject to U.S. withholding tax at a 30% rate, subject to
reduction under an applicable treaty, unless such income is effectively
connected income as described below in "Tax Consequences to Non-United States
Holders-Effectively Connected Income." In order to obtain a reduced rate of
withholding, a Non-United States Holder will be required to provide a properly
executed IRS Form W-8BEN certifying its entitlement to benefits under a treaty.
A Non-United States Holder who is subject to withholding tax under such
circumstances should consult his own tax adviser as to whether he can obtain a
refund for all or a portion of the withholding tax.

         If we fail to comply with our obligations under "Description of 
Notes--Registration Rights of the Noteholders," we may be required to make 
payments to noteholders who have converted their notes into shares of common 
stock. The tax treatment of any such payments for U.S. federal income tax 
purposes is unclear. Any such payment made to a Non-United States Holder of 
our common stock likely would be subject to U.S. withholding tax at a 30% 
rate unless such payment is effectively connected income as described below 
in "Tax Consequences to Non-United States Holders-Effectively Connected 
Income," but such payments likely would not qualify as "dividends" for 
purposes of determining the applicability of any exemption from, or reduced 
rate of, the withholding tax under a treaty.



                                       46



EFFECTIVELY CONNECTED INCOME

         If a Non-United States Holder of a note or of our common stock is
engaged in a trade or business in the United States, and if interest on the
note, gain realized on a sale, exchange or other disposition of the note or of
our common stock, or a dividend on the note or on our common stock, is
effectively connected with the conduct of the trade or business, the Non-United
States Holder, although exempt from U.S. withholding tax, will generally be
taxed in the same manner as a United States Holder (see "Tax Consequences to
United States Holders" above), except that the Non-United States Holder will be
required to provide a properly executed IRS Form W-8ECI in order to claim an
exemption from withholding tax. These Non-United States Holders should consult
their own tax advisers with respect to other tax consequences of the ownership
of the note or of our common stock, including the possible imposition of a 30%
branch profits tax.

BACKUP WITHHOLDING AND INFORMATION REPORTING

         Information returns may be filed with the Internal Revenue Service in
connection with payments on the notes and our common stock and the proceeds from
a sale or other disposition of the notes or our common stock. A United States
Holder may be subject to United States backup withholding tax on these payments
if it fails to provide its taxpayer identification number to the paying agent
and comply with certification procedures or otherwise establish an exemption
from backup withholding. A Non-United States Holder may be subject to United
States backup withholding tax on these payments unless the Non-United States
Holder complies with certification procedures to establish that it is not a U.S.
person. The amount of any backup withholding from a payment will be allowed as a
credit against the holder's U.S. federal income tax liability and may entitle
the holder to a refund, provided that the required information is timely
furnished to the Internal Revenue Service.

         THE PRECEDING DISCUSSION OF CERTAIN UNITED STATES FEDERAL INCOME TAX
CONSEQUENCES IS FOR GENERAL INFORMATION ONLY AND MAY NOT BE APPLICABLE DEPENDING
UPON A HOLDER'S PARTICULAR SITUATION. ACCORDINGLY, EACH INVESTOR SHOULD CONSULT
ITS OWN TAX ADVISOR AS TO PARTICULAR TAX CONSEQUENCES TO IT OF PURCHASING,
HOLDING AND DISPOSING OF THE NOTES AND THE COMMON STOCK INTO WHICH THE NOTES MAY
BE CONVERTED OR FOR WHICH THE NOTES MAY BE EXCHANGED, INCLUDING THE
APPLICABILITY AND EFFECT OF ANY STATE, LOCAL OR FOREIGN TAX LAWS, AND OF ANY
PROPOSED CHANGES IN APPLICABLE LAWS.

                                       47


                                 SELLING HOLDERS

         The notes were originally issued by us and sold by SG Cowen & Co., LLC,
Needham & Company, Inc., Wells Fargo Securities, LLC and WR Hambrecht + Co, LLC,
as the initial purchasers, in a transaction exempt from the registration
requirements of the Securities Act to qualified institutional buyers. Selling
holders, including their transferees, pledgees or donees or their successors,
may from time to time offer and sell any or all of the notes and common stock
into which the notes are convertible.

         The selling holders have represented to us that they purchased the
notes and the common stock issuable upon conversion of the notes for their own
account for investment only and not with a view toward selling or distributing
them, except through sales registered under the Securities Act or exemptions. We
agreed with the initial purchasers to file this registration statement to
register the resale of the notes and the common stock. We also agreed to prepare
and file all necessary amendments and supplements to the registration statement
to keep it effective until the date on which the notes and the common stock
issuable upon conversion of the notes no longer qualify as "registrable
securities" under our registration rights agreement.

         The following table shows information, as of November 1, 2004, with
respect to the selling holders and the principal amounts of notes and common
stock they beneficially own that may be offered under this prospectus. The
information is based on information provided by or on behalf of the selling
holders.

         The following table sets forth:

              (1) the name of each selling holder who has provided us with
         notice as of the date of this prospectus pursuant to the registration
         rights agreement that they may intend to sell or otherwise dispose of
         notes and/or shares of common stock issuable upon conversion of the
         notes pursuant to the registration statement,

              (2) the principal amount of notes and the number of shares of our
         common stock issuable upon conversion of the notes that they may sell
         from time to time pursuant to the registration statement, and

              (3) the amount of outstanding notes and shares of our common stock
         beneficially owned by the selling holder after completion of the
         offering (excluding any shares owned or acquired other than upon
         conversion of the notes).

         To our knowledge, no selling holder nor any of its affiliates has held
any position or office with, been employed by or otherwise has had any material
relationship with us or our affiliates, during the three years prior to the date
of this prospectus, except that SG Cowen & Co., LLC, Needham & Company, Inc.,
Wells Fargo Securities, LLC and WR Hambrecht + Co, LLC were the initial
purchasers of the notes and served as underwriters of our offering of 4,645,000
shares of our common stock on August 7, 2003.

         A selling holder may offer all or some portion of the notes and shares
of the common stock issuable upon conversion of the notes. Accordingly, no
estimate can be given as to the amount or percentage of notes or our common
stock that will be held by the selling holders upon termination of sales
pursuant to this prospectus. In addition, the selling holders identified below
may have sold, transferred or disposed of all or a portion of their notes since
the date on which they provided the information regarding their holdings in
transactions exempt from the registration requirements of the Securities Act.

         The information contained under the column heading "Shares of Common
Stock That May Be Sold" represents shares issuable upon conversion of the
principal amount of notes listed and assumes conversion of the full amount of
the notes at the initial conversion rate of 33.5909 shares per $1,000 in
principal amount of the notes. The name "Unidentified Holders" represents the
remaining selling holders. We are unable to provide the names of these holders
because certain of these notes are currently evidenced by a global convertible
note which has been deposited with DTC and registered in the name of Cede & Co.
as DTC's nominee.

                                       48




                                                                                                  SHARES OF
                                              PRINCIPAL                           PRINCIPAL         COMMON
                                              AMOUNT OF                           AMOUNT OF         STOCK
                                                NOTES           SHARES OF        NOTES OWNED     BENEFICIALLY
                                             BENEFICIALLY        COMMON             AFTER        OWNED AFTER
                                              OWNED THAT        STOCK THAT      COMPLETION OF    COMPLETION OF
                    NAME                    MAY BE SOLD ($)    MAY BE SOLD       OFFERING ($)    OFFERING (1)
----------------------------------------------------------------------------------------------------------------
                                                                                      
Polaris Vega Fund L.P.                       1,600,000              53,745             0                  0
Pioneer U.S. High Yield Corp.                3,900,000             131,005             0                  0
Pioneer High Yield Fund                     34,600,000           1,162,245             0                  0
Pioneer High Yield VCT Portfolio               375,000              12,597             0                  0
GE Singapore Life Insurance Fund               125,000               4,199             0                  0
SG Americas Securities, LLC                  5,400,000             181,391             0                  0
Sunrise Partners Limited Partnership         4,900,000             164,595             0                  0
UBS AG London - F/B/O HFS                    3,000,000             100,773             0                  0
UBS O'Connor LLC - F/B/O O'Connor Global
Convertible Arbitrage Master Ltd.              500,000              16,795             0                  0
Wachovia Bank National Association           9,000,000             302,318             0                  0
CooperNeff Convertible Strategies (Cayman)
Master Fund, LP                                649,000              21,800             0                  0
Singlehedge US Convertible Arbitrage Fund      136,000               4,568             0                  0
Lyxor/Convertible Arbitrage Fund Limited       109,000               3,661             0                  0
BNP Paribas Equity Strategies, SNC             586,000              19,684             0                  0
Sturgeon Limited, Washington Mall - Phase I    120,000               4,031             0                  0
Allstate Insurance Company                   1,000,000              33,591             0                  0
Highbridge International, LLC                3,500,000             117,568             0                  0
Putnam Convertible Income-Growth Trust       4,300,000             144,441             0                  0
Fidelity Financial Trust: Fidelity 
Convertible Securities Fund                  9,000,000             302,318             0                  0
DBAG London                                  1,500,000              50,386             0                  0
Unidentified Holders                        15,700,000             527,377             0                  0


(1)      For purposes of the information set forth in this table, we have
assumed, unless informed otherwise by the selling holder, that each selling
holder beneficially owns no shares of our common stock other than shares
issuable upon conversion of the notes.

         Information concerning the selling holders may change from time to time
and any changed information will be set forth in supplements to this prospectus
if and when necessary. In addition, the per share conversion price, and
therefore the number of shares of common stock issuable upon conversion of the
notes, is subject to adjustment. As a result, the aggregate principal amount of
notes and the number of shares of common stock into which the notes are
convertible may increase or decrease.

                                       49


                              PLAN OF DISTRIBUTION

         The selling holders and their successors, including their transferees,
pledgees or donees or their successors, may sell the notes and our common stock
into which the notes are convertible directly to purchasers or through
underwriters, broker-dealers or agents, who may receive compensation in the form
of discounts, concessions or commissions from the selling holders or the
purchasers. These discounts, concessions or commissions as to any particular
underwriter, broker-dealer or agent may be in excess of those customary in the
types of transactions involved.

         The notes and common stock issuable upon conversion of the notes may be
sold in one or more transactions at fixed prices, at prevailing market prices at
the time of sale, at prices related to the prevailing market prices, at varying
prices determined at the time of sale, or at negotiated prices. These sales may
be effected in transactions, which may involve crosses or block transactions:

         -    on any national securities exchange or U.S. inter-dealer system of
              a registered national securities association on which the notes or
              our common stock may be listed or quoted at the time of sale;

         -    in the over-the-counter market;

         -    in transactions otherwise than on these exchanges or systems or in
              the over-the-counter market;

         -    through the writing of options, whether the options are listed on
              an options exchange or otherwise; or

         -    through the settlement of short sales.

         In connection with the sale of the notes and the common stock issuable
upon conversion of the notes, the selling holders may enter into hedging
transactions with broker-dealers or other financial institutions, which may in
turn engage in short sales of the notes or common stock issuable upon conversion
of the notes in the course of hedging the positions they assume. The selling
holders may also sell the notes or common stock short and deliver these
securities to close out their short positions, or loan or pledge the notes or
common stock issuable upon conversion of the notes to broker-dealers that in
turn may sell these securities.

         The aggregate proceeds to the selling holders from the sale of the
notes or common stock offered by them will be the purchase price of the notes or
common stock less discounts and commissions, if any. Each of the selling holders
reserves the right to accept and, together with their agents from time to time,
to reject, in whole or in part, any proposed purchase of notes or common stock
to be made directly or through agents. We will not receive any of the proceeds
from this offering.

         Our common stock is listed for trading on The Nasdaq National Market
under the symbol "EPIX." The notes are currently eligible for trading on the
PORTAL System of the NASD.

         In order to comply with the securities laws of some states, if
applicable, the notes and common stock issuable upon conversion of the notes may
be sold in these jurisdictions only through registered or licensed brokers or
dealers. In addition, in some states the notes and common stock issuable upon
conversion of the notes may not be sold unless they have been registered or
qualified for sale or an exemption from registration or qualification
requirements is available and is complied with.

         The selling holders and any underwriters, broker-dealers or agents that
participate in the sale of the notes and common stock issuable upon conversion
of the notes may be "underwriters" within the meaning of Section 2(11) of the
Securities Act. Any discounts, commissions, concessions or profit they earn on
any resale of the shares may be underwriting discounts and commissions under the
Securities Act. Selling holders who are "underwriters" within the meaning of
Section 2(11) of the Securities Act will be subject to the prospectus delivery
requirements of the Securities Act. The selling holders have acknowledged that
they understand their obligations to comply with the provisions of the Exchange
Act and the rules thereunder relating to stock manipulation, particularly
Regulation M.

                                       50


         In addition, any securities covered by this prospectus which qualify
for sale pursuant to Rule 144 or Rule 144A of the Securities Act may be sold
under Rule 144 or Rule 144A rather than pursuant to this prospectus.

         To the extent required, the specific notes or shares of our common
stock to be sold, the names of the selling holders, the respective purchase
prices and public offering prices, the names of any agent, dealer or
underwriter, and any applicable commissions or discounts with respect to a
particular offer will be set forth in an accompanying prospectus supplement or,
if appropriate, a post-effective amendment to the registration statement of
which this prospectus is a part.

         We entered into a registration rights agreement for the benefit of
holders of the notes to register their notes and our common stock issuable upon
conversion of the notes under applicable federal and state securities laws under
specific circumstances and at specific times. The registration rights agreement
provides for cross-indemnification of the selling holders and us and our
respective directors, officers and controlling persons against specific
liabilities in connection with the offer and sale of the notes and our common
stock issuable upon conversion of the notes, including liabilities under the
Securities Act.

                                  LEGAL MATTERS

         Certain legal matters relating to the notes and the common stock
issuable upon conversion of the notes offered hereby will be passed upon for us
by Mintz, Levin, Cohn, Ferris, Glovsky and Popeo, P.C., Boston, Massachusetts.

                                     EXPERTS

         The financial statements of EPIX Pharmaceuticals, Inc. appearing in 
EPIX Pharmaceuticals, Inc.'s Annual Report (Form 10-K) for the year ended 
December 31, 2003 have been audited by Ernst & Young LLP, independent 
registered public accounting firm, as set forth in their report thereon 
included therein and incorporated herein by reference. Such financial 
statements are incorporated herein by reference in reliance upon such report 
given on the authority of such firm as experts in accounting and auditing.

                       WHERE YOU CAN FIND MORE INFORMATION

         We file reports, proxy statements and other documents with the
Securities and Exchange Commission. You may read and copy any document we file
with the SEC at the public reference facilities the SEC maintains at:

         Room 1024, Judiciary Plaza
         450 Fifth Street, N.W.
         Washington, D.C. 20549

         Please call the SEC at 1-800-SEC-0330 for further information on the
public reference rooms.

         The SEC also maintains a Web site, the address of which is
http://www.sec.gov. That site also contains our annual, quarterly and special
reports, proxy statements, information statements and other information.

         This prospectus is part of a registration statement that we filed with
the SEC. The registration statement contains more information than this
prospectus regarding us and the securities, including exhibits and schedules.
You can obtain a copy of the registration statement from the SEC at the address
listed above or from the SEC's Web site.

         You may also inspect our reports and other information concerning us at
the offices of the National Association of Securities Dealers, Inc. 1735 K
Street, N.W., Washington, D.C. 20006.

                     INCORPORATION OF DOCUMENTS BY REFERENCE

The SEC allows us to "incorporate by reference" the information we file with it,
which means that we can disclose important information to you by referring you
to those documents. The information incorporated by reference is considered to
be part of this prospectus and information we file later with the SEC will
automatically update and supersede this information. We incorporate by reference
the documents listed below and any future filings made with the SEC under
Sections 13(a), 13(c), 14 or 15(d) of the Securities Exchange Act of 1934,
PROVIDED, HOWEVER, that we are not

                                       51


incorporating any information furnished under either Item 2.02 or Item 7.01 
(or their predecessor items) of the Form 8-K. The documents we are 
incorporating by reference are:

         -    Annual Report on Form 10-K for the year ended December 31, 2003,
              filed with the SEC on March 8, 2004 (File No. 000-21863);
         -    Quarterly Reports on Form 10-Q for our fiscal quarters ended 
              June 30, 2004, filed with the SEC on August 3, 2004, March
              31, 2004, filed with the SEC on May 5, 2004 and September 30,
              2004, filed with the SEC on November 2, 2004 (File No. 000-21863);
         -    Definitive Proxy Statement filed with the SEC for our Annual
              Meeting of Stockholders held on May 26, 2004 (File No. 000-21863);
         -    Reports on Form 8-K filed with the SEC on January 14, 2004,
              February 17, 2004, June 7, 2004, June 8, 2004, July 15, 2004,
              August 5, 2004, September 7, 2004, September 21, 2004, 
              October 4, 2004, October 27, 2004, and November 3, 2004 (File 
              No. 000-21863); and
         -    The description of our common stock contained in "Description of
              Capital Stock" in the registration statement on Form S-1 filed
              with the SEC on January 30, 1997 (File No. 333-17581) and any
              amendments or reports filed to update such description.

You may request, orally or in writing, a copy of these documents, which will be
provided to you at no cost, by contacting:

         Investor Relations
         EPIX Pharmaceuticals, Inc.
         161 First Street
         Cambridge, Massachusetts 02142
         Telephone: (617) 250-6000

We maintain a website at www.epixpharma.com. The information contained on our
website does not constitute a part of this prospectus.

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