Filed Pursuant to Rule 424(b)(3)
Registration No. 333-227622

MERGER PROPOSAL—YOUR VOTE IS VERY IMPORTANT

October 30, 2018

Dear Shareholders of Keryx Biopharmaceuticals, Inc. and Shareholders of Akebia Therapeutics, Inc.:

As previously announced, the Boards of Directors of Keryx Biopharmaceuticals, Inc. (“Keryx”) and Akebia Therapeutics, Inc. (“Akebia”) have unanimously approved a merger. Keryx, Akebia, and Alpha Therapeutics Merger Sub, Inc., a wholly owned subsidiary of Akebia ( “Merger Sub”), entered into an Agreement and Plan of Merger, dated as of June 28, 2018, as amended on October 1, 2018 (and as amended from time to time, the “Merger Agreement”), pursuant to which Merger Sub will merge with and into Keryx, with Keryx becoming a wholly owned subsidiary of Akebia (the “Merger”). The combined company will keep the name Akebia Therapeutics, Inc. Upon consummation of the Merger, each issued and outstanding share of common stock of Keryx, $0.001 par value per share (“Keryx Share”), will be converted into the right to receive 0.37433 shares (the “Exchange Multiplier”) of common stock of Akebia, par value $0.00001 per share (“Akebia Share”), and cash in lieu of fractional shares. This Exchange Multiplier will not be adjusted for changes in the market price of either Keryx Shares or Akebia Shares between the date of signing of the Merger Agreement and consummation of the Merger. Because Akebia’s share price will fluctuate between the date of signing and the completion of the Merger, and because the Exchange Multiplier is fixed and will not be adjusted to reflect changes in Akebia’s or Keryx’s share price, the value of the Akebia Shares received by Keryx shareholders in the Merger may differ from the implied value based on the share price on the date of signing of the Merger Agreement or the date of this joint proxy statement/prospectus. We urge you to obtain current share price quotations for Akebia Shares and Keryx Shares.

Immediately following the effective time of the Merger, Keryx shareholders and Akebia shareholders are expected to own approximately 50.6% and 49.4%, respectively, of Akebia Shares, calculated based on the companies’ fully diluted market capitalizations as of the date of signing of the Merger Agreement and also taking into account the 4,000,000 additional Keryx Shares expected to be issued to Baupost Group Securities, L.L.C. in connection with the conversion under that certain Notes Conversion Agreement prior to the consummation of the Merger. Keryx Shares and Akebia Shares are currently listed on The Nasdaq Capital Market and The Nasdaq Global Market, respectively, under the symbols “KERX” and “AKBA,” respectively. Following the Merger, Akebia Shares will continue to be listed on The Nasdaq Global Market under Akebia’s current symbol, “AKBA.” Following the consummation of the Merger, Keryx Shares will no longer be listed on any stock exchange or quotation system, and Keryx will cease to be a publicly traded company. Akebia will continue as the combined company, with Keryx as its wholly owned subsidiary.

To obtain the approvals of the Keryx shareholders and the Akebia shareholders required in connection with the Merger, Keryx will hold a special meeting of its shareholders (the “Keryx Special Meeting”) and Akebia will hold a special meeting of its shareholders (the “Akebia Special Meeting”).

At the Keryx Special Meeting, Keryx shareholders will be asked to consider and vote on, among other things, a proposal to adopt the Merger Agreement (the “Keryx Merger Proposal”).

At the Akebia Special Meeting, Akebia shareholders will be asked to consider and vote on, among other things, the issuance of Akebia Shares in connection with the Merger (the “Akebia Share Issuance Proposal”).

We cannot consummate the Merger unless the shareholders of Keryx approve the Keryx Merger Proposal and the shareholders of Akebia approve the Akebia Share Issuance Proposal, each as described herein. Your vote is very important, regardless of the number of shares you own. Whether or not you expect to attend either the Keryx Special Meeting or the Akebia Special Meeting in person, please submit a proxy to vote your shares as promptly as possible so that your shares may be represented and voted at the Keryx Special Meeting or Akebia Special Meeting, as applicable.

The Keryx Board of Directors has carefully considered and unanimously approved the Merger Agreement and determined that the Merger Agreement and the transactions contemplated thereby, including the Merger, are advisable and in the best interests of Keryx and its shareholders. The Keryx Board of Directors unanimously recommends that Keryx shareholders vote “FOR” the Keryx Merger Proposal and “FOR” each of the other proposals to be considered at the Keryx Special Meeting and described in the accompanying joint proxy statement/prospectus.

The Akebia Board of Directors has carefully considered and unanimously approved the Merger Agreement and determined that the Merger Agreement and the transactions contemplated thereby, including the Merger, are advisable and in the best interests of Akebia and its shareholders. The Akebia Board of Directors unanimously recommends that Akebia shareholders vote “FOR” the Akebia Share Issuance Proposal and “FOR” each of the other proposals to be considered at the Akebia Special Meeting and described in the accompanying joint proxy statement/prospectus.

The obligations of Keryx and Akebia to consummate the Merger are subject to the satisfaction or waiver of several conditions set forth in the Merger Agreement, including receipt of shareholder approval for the required proposals described above. The accompanying joint proxy statement/prospectus contains detailed information about Keryx, Akebia, the Keryx Special Meeting, the Akebia Special Meeting, the Merger Agreement, the Merger and the other business to be considered by the Keryx shareholders and Akebia shareholders at the Keryx Special Meeting and the Akebia Special Meeting, respectively. Keryx and Akebia encourage you to read the accompanying joint proxy statement/prospectus carefully. In particular, you should read the “Risk Factors” section beginning on page 39 of the accompanying joint proxy statement/prospectus for a discussion of the risks you should consider in evaluating the Merger and how it will affect you.

On behalf of the Keryx Board of Directors and the Akebia Board of Directors, thank you for your consideration and continued support.

Neither the Securities and Exchange Commission nor any state securities commission has approved or disapproved of the Merger, the securities to be issued in connection with the Merger or any other transaction described in the accompanying joint proxy statement/prospectus or passed upon the adequacy or accuracy of the disclosure in the accompanying joint proxy statement/prospectus. Any representation to the contrary is a criminal offense.

The accompanying joint proxy statement/prospectus is dated October 30, 2018 and is first being mailed to the Keryx shareholders and Akebia shareholders on or about October 31, 2018.

ADDITIONAL INFORMATION

The accompanying joint proxy statement/prospectus incorporates by reference important business and financial information about Keryx and Akebia from other documents that are not included in or delivered with the accompanying joint proxy statement/prospectus. This information is available to you without charge upon your request. You can obtain the documents incorporated by reference into the accompanying joint proxy statement/prospectus by requesting them in writing or by telephone from the appropriate company at the following addresses and telephone numbers:

Keryx Biopharmaceuticals, Inc. One Marina Park Drive, 12th Floor Boston, Massachusetts 02210 Attention: Investor Relations Telephone: (617) 466-3500   or		Akebia Therapeutics, Inc. 245 First Street Cambridge, Massachusetts 02142 Attention: Investor Relations Telephone: (617) 844-6130 http://ir.akebia.com/contact-investor-relations   or
1290 Avenue of the Americas, 9th Floor New York, NY 10104 Toll-Free: (888) 680-1525		1407 Broadway, 27th Floor New York, NY 10018 Toll-Free: (800) 322-2885 Email: proxy@mackenziepartners.com

Keryx shareholders and Akebia shareholders may also consult the websites of Keryx or Akebia for more information concerning the Merger and other transactions described in the accompanying joint proxy statement/prospectus. The website of Keryx is www.keryx.com and the website of Akebia is www.akebia.com. Information included on these websites is not incorporated by reference into the accompanying joint proxy statement/prospectus.

If you would like to request any documents, you must do so by December 8, 2018, in order to receive them before the special meetings.

For a more detailed description of the information incorporated by reference in the accompanying joint proxy statement/prospectus and how you may obtain it, see “Where You Can Find More Information” beginning on page 186 of the accompanying joint proxy statement/prospectus.

AKEBIA THERAPEUTICS, INC.

245 First Street

Cambridge, Massachusetts 02142

NOTICE OF SPECIAL MEETING OF SHAREHOLDERS

TO BE HELD ON DECEMBER 11, 2018

To the Shareholders of Akebia Therapeutics, Inc.:

We cordially invite you to attend a special meeting of the shareholders of Akebia Therapeutics, Inc. (“Akebia”) being held in connection with a proposed merger with Keryx Biopharmaceuticals, Inc. (“Keryx”). On June 28, 2018, Akebia, Keryx, and Alpha Therapeutics Merger Sub, Inc., a wholly owned subsidiary of Akebia (“Merger Sub”), entered into an Agreement and Plan of Merger, dated as of June 28, 2018, as amended on October 1, 2018 (and as amended from time to time, the “Merger Agreement”), pursuant to which Merger Sub will merge with and into Keryx, with Keryx surviving as a wholly owned subsidiary of Akebia (the “Merger”).

The special meeting will take place at 11 a.m. local time, on December 11, 2018, at the offices of Latham & Watkins LLP, which are located at 200 Clarendon Street, Boston, Massachusetts 02116 (the “Akebia Special Meeting”). At the Akebia Special Meeting, you will be asked to consider and vote upon the following proposals:

The approval by Akebia shareholders of the Akebia Share Issuance Proposal is a condition to the consummation of the Merger. If the Akebia Share Issuance Proposal is not approved, the Merger will not be consummated. The approval of the Akebia Adjournment Proposal is not required for the consummation of the Merger. The Akebia Board of Directors (the “Akebia Board”) is not aware of any other business to be acted upon at the Akebia Special Meeting.

Please refer to the accompanying joint proxy statement/prospectus for further information with respect to the business to be transacted at the Akebia Special Meeting.

The Akebia Board has set October 22, 2018 as the record date for the Akebia Special Meeting. Only holders of record of Akebia Shares as of 5:00 p.m. U.S. Eastern Time on October 22, 2018 will be entitled to notice of and to vote at the Akebia Special Meeting and any adjournments thereof. Any shareholder entitled to attend and vote at the Akebia Special Meeting is entitled to appoint a proxy to attend and vote on such shareholder’s behalf. Such proxy need not be a holder of Akebia Shares.

To be approved, the Akebia Share Issuance Proposal and the Akebia Adjournment Proposal require the affirmative vote of the holders of a majority of the votes cast affirmatively or negatively thereon at the Akebia Special Meeting.

The failure of any shareholder of record of Akebia to submit a signed proxy card, grant a proxy electronically over the Internet or by telephone or to vote in person by ballot at the Akebia Special Meeting will not have an effect on the outcome of the Akebia Share Issuance Proposal or the Akebia Adjournment Proposal. An abstention will have no effect on the outcome of the Akebia Share Issuance Proposal or the Akebia Adjournment Proposal. If you hold your Akebia Shares in “street name” through a bank, broker, or other nominee and you do not instruct your bank, broker, or other nominee on how to vote your shares, your bank, broker, or other nominee will not be permitted to vote your shares on any of the Akebia Proposals, which will have no effect on the outcome of the Akebia Share Issuance Proposal or the Akebia Adjournment Proposal.

Your vote is very important. Whether or not you expect to attend the Akebia Special Meeting in person, we urge you to submit your proxy with respect to your Akebia Shares as promptly as possible by: (1) accessing the Internet website specified on your proxy card; (2) calling the toll-free number specified on your proxy card; or (3) signing and returning the enclosed proxy card in the postage-paid envelope provided, to ensure that your Akebia Shares are represented and voted at the Akebia Special Meeting. Submitting a proxy now will not prevent you from being able to vote in person at the Akebia Special Meeting. If your Akebia Shares are held in “street name” in the name of a bank, broker, or other nominee, please follow the instructions on the voting instruction card furnished by the record holder.

The Akebia Board has unanimously approved the Merger Agreement and the transactions contemplated thereby, including the issuance of Akebia Shares, and has determined that the Merger Agreement and the Merger, including the issuance of Akebia Shares, are advisable, fair to, and in the best interests of Akebia and its shareholders. The Akebia Board unanimously recommends that you vote “FOR” the Akebia Share Issuance Proposal and “FOR” the Akebia Adjournment Proposal.

YOUR VOTE IS IMPORTANT!

WHETHER OR NOT YOU EXPECT TO ATTEND THE AKEBIA SPECIAL MEETING IN PERSON, WE URGE YOU TO SUBMIT YOUR PROXY AS PROMPTLY AS POSSIBLE (1) VIA THE INTERNET, (2) BY TELEPHONE OR (3) BY MARKING, SIGNING AND DATING THE ENCLOSED AKEBIA PROXY CARD AND RETURNING IT IN THE POSTAGE-PAID ENVELOPE PROVIDED. IF YOU ATTEND THE AKEBIA SPECIAL MEETING AND WISH TO VOTE YOUR AKEBIA SHARES IN PERSON, YOU MAY DO SO AT ANY TIME PRIOR TO THE CLOSING OF THE POLLS AT THE SPECIAL MEETING. You may revoke your proxy or change your vote at any time before the polls close at the Akebia Special Meeting. If your Akebia Shares are held in “street name” in the name of a bank, broker, or other nominee holder of record, please follow the instructions on the voting instruction form furnished to you by such record holder.

We urge you to read the accompanying joint proxy statement/prospectus, including all documents incorporated by reference into the accompanying joint proxy statement/prospectus, and its annexes and exhibits carefully and in their entirety. If you have any questions concerning the Merger Agreement, the Merger, the Akebia Proposals, the Akebia Special Meeting or the accompanying joint proxy statement/prospectus, would like additional copies of the accompanying joint proxy statement/prospectus or need help voting your Akebia Shares, please contact:

1407 Broadway, 27^th Floor

New York, NY 10018

Toll-Free: (800) 322-2885

Email: proxy@mackenziepartners.com

or

245 First Street

Cambridge, Massachusetts 02142

Attention: Investor Relations

Telephone: (617) 844-6130

http://ir.akebia.com/contact-investor-relations

KERYX BIOPHARMACEUTICALS, INC.

One Marina Park Drive, 12^th Floor

Boston, Massachusetts 02210

NOTICE OF SPECIAL MEETING OF SHAREHOLDERS

TO BE HELD ON DECEMBER 11, 2018

To the Shareholders of Keryx Biopharmaceuticals, Inc.:

We cordially invite you to attend a special meeting of the shareholders of Keryx Biopharmaceuticals, Inc. (“Keryx”) being held in connection with a proposed merger with Akebia Therapeutics, Inc. (“Akebia”). On June 28, 2018, Akebia, Keryx and Alpha Therapeutics Merger Sub, Inc., a wholly owned subsidiary of Akebia (“Merger Sub”), entered into an Agreement and Plan of Merger, dated as of June 28, 2018, as amended on October 1, 2018 (and as amended from time to time, the “Merger Agreement”), pursuant to which Merger Sub will merge with and into Keryx, with Keryx surviving as a wholly owned subsidiary of Akebia (the “Merger”).

The special meeting will be held at 11 a.m. local time, on December 11, 2018, at the offices of Goodwin Procter LLP, which are located at 100 Northern Avenue, Boston, Massachusetts 02210 (the “Keryx Special Meeting”). At the Keryx Special Meeting, you will be asked to consider and vote upon the following proposals:

Approval of the Keryx Merger Proposal is required for the consummation of the Merger. Neither the approval of the Keryx Adjournment Proposal nor the approval of the Keryx Advisory Compensation Proposal is required for the consummation of the Merger. The Keryx Board of Directors (the “Keryx Board”) is not aware of any other business to be acted upon at the Keryx Special Meeting.

Approval of the Keryx Merger Proposal requires the affirmative vote of the holders of a majority of all outstanding shares of Keryx common stock, $0.001 par value per share (the “Keryx Shares”), entitled to vote at the Keryx Special Meeting. Approval of the Keryx Adjournment Proposal and the Keryx Advisory Compensation Proposal require the affirmative vote of the holders of a majority of the voting interest of the shares present, in person or by proxy, and entitled to vote on the applicable proposal at the Keryx Special Meeting.

Each of the Keryx Merger Proposal, Keryx Adjournment Proposal, and Keryx Advisory Compensation Proposal is described in more detail in the accompanying joint proxy statement/prospectus, which you should read carefully in its entirety.

The failure of any shareholder of record of Keryx to submit a signed proxy card, grant a proxy electronically over the Internet or by telephone or to vote in person by ballot at the Keryx Special Meeting will have the same effect as a vote “AGAINST” the Keryx Merger Proposal, but will not have an effect on the outcome of the Keryx Adjournment Proposal or the Keryx Advisory Compensation Proposal. If you hold your shares in “street name,” failure to instruct your bank, broker, or other nominee on how to vote your shares will have the same effect as a vote “AGAINST” the Keryx Merger Proposal, but will not have any effect on the Keryx Adjournment Proposal or the Keryx Advisory Compensation Proposal. Abstentions will have the same effect as a vote “AGAINST” the Keryx Merger Proposal, the Keryx Adjournment Proposal and the Keryx Advisory Compensation Proposal.

The Keryx Board has set October 22, 2018 as the record date for the Keryx Special Meeting. Only holders of record of Keryx Shares as of 5:00 p.m. U.S. Eastern Time on October 22, 2018 will be entitled to notice of and to vote at the Keryx Special Meeting and any adjournments thereof. Any shareholder entitled to attend and vote at the Keryx Special Meeting is entitled to appoint a proxy to attend and vote on such shareholder’s behalf. Such proxy need not be a holder of Keryx Shares.

Your vote is very important. To ensure your representation at the Keryx Special Meeting, please complete and return the enclosed proxy card or submit your proxy by telephone or through the Internet. Please submit your proxy promptly whether or not you expect to attend the Keryx Special Meeting. Submitting a proxy now will not prevent you from being able to vote in person at the Keryx Special Meeting. If your Keryx Shares are held in “street name” in the name of a bank, broker, or other nominee, follow the instructions on the voting instruction card furnished to you by such bank, broker, or other nominee.

The Keryx Board has unanimously approved the Merger Agreement and the transactions contemplated thereby, and has determined that the Merger Agreement and the Merger are advisable, fair to, and in the best interests of Keryx and its shareholders. The Keryx Board therefore unanimously recommends that you vote “FOR” the Keryx Merger Proposal, “FOR” the Keryx Adjournment Proposal and “FOR” the Keryx Advisory Compensation Proposal.

YOUR VOTE IS IMPORTANT!

WHETHER OR NOT YOU EXPECT TO ATTEND THE KERYX SPECIAL MEETING IN PERSON, WE URGE YOU TO SUBMIT YOUR PROXY AS PROMPTLY AS POSSIBLE (1) VIA THE INTERNET, (2) BY TELEPHONE OR (3) BY MARKING, SIGNING AND DATING THE ENCLOSED KERYX PROXY CARD AND RETURNING IT IN THE POSTAGE-PAID ENVELOPE PROVIDED. IF YOU ATTEND THE KERYX SPECIAL MEETING AND WISH TO VOTE YOUR KERYX SHARES IN PERSON, YOU MAY DO SO AT ANY TIME PRIOR TO CLOSING OF THE POLLS. You may revoke your proxy or change your vote at any time before the polls close at the Keryx Special Meeting. If your Keryx Shares are held in “street name” in the name of a bank, broker, or other nominee holder of record, please follow the instructions on the voting instruction form furnished to you by such record holder.

We urge you to read the accompanying joint proxy statement/prospectus, including all documents incorporated by reference into the accompanying joint proxy statement/prospectus, and its annexes and exhibits carefully and in their entirety. If you have any questions concerning the Merger Agreement, the Merger, the Keryx Proposals, the Keryx Special Meeting or the accompanying joint proxy statement/prospectus, would like additional copies of the accompanying joint proxy statement/prospectus or need help voting your Keryx Shares, please contact:

1290 Avenue of the Americas, 9^th Floor

New York, NY 10104

Toll-Free: (888) 680-1525

or

One Marina Park Drive, 12^th Floor

Boston, MA 02210

Attention: Investor Relations

Telephone: (617) 466-3500

TABLE OF CONTENTS

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QUESTIONS AND ANSWERS ABOUT THE MERGER AND THE SPECIAL MEETINGS

The following are brief answers to certain questions that you may have regarding the Merger Agreement, the Merger, the issuance of Akebia Shares in connection with the Merger, the Keryx Special Meeting, the Akebia Special Meeting and the Merger Consideration (each as defined below). You are urged to read carefully this entire joint proxy statement/prospectus and additional important information contained in the annexes and exhibits to, and the documents incorporated by reference into, this joint proxy statement/prospectus because the information in this section may not provide all of the information that might be important to you in determining how to vote. See “Incorporation of Certain Documents by Reference” and “Where You Can Find More Information” beginning on pages 185 and 186, respectively, in this joint proxy statement/prospectus.

In the Merger, each share of common stock of Keryx, par value $0.001 per share (“Keryx Share”), issued and outstanding (other than shares held by Akebia, Merger Sub, any subsidiaries of Akebia or Keryx, or by Keryx as treasury shares) immediately prior to the effective time of the Merger (the “Effective Time”) will become the right to receive 0.37433 shares (the “Exchange Multiplier”) of common stock of Akebia, par value $0.00001 per share (“Akebia Shares”), and cash in lieu of fractional shares (such consideration, the “Merger Consideration”).

Immediately following the Effective Time, Keryx shareholders and Akebia shareholders are expected to own approximately 50.6% and 49.4%, respectively, of the Akebia Shares, based on the companies’ fully diluted market capitalizations as of the date of signing of the Merger Agreement and also taking into account the 4,000,000 additional Keryx Shares (the “Additional Shares”) expected to be issued to Baupost Group Securities, L.L.C. (“Baupost”) in connection with the conversion under that certain Notes Conversion Agreement, dated as of June 28, 2018, by and among Keryx, Baupost and Akebia (the “Notes Conversion Agreement”) prior to the consummation of the Merger, as more fully described in “The Merger—Notes Conversion Transactions” beginning on page 68 of this joint proxy statement/prospectus.

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Consummation of the Merger requires certain approvals by both Keryx shareholders and Akebia shareholders. To obtain these required approvals, Keryx will hold the Keryx Special Meeting to request that the Keryx shareholders approve, among other things, a proposal to adopt the Merger Agreement (the “Keryx Merger Proposal”), and Akebia will hold the Akebia Special Meeting to request that the Akebia shareholders approve, among other things, the issuance of Akebia Shares in connection with the Merger (the “Akebia Share Issuance Proposal”). Further information about the Keryx Special Meeting, the Akebia Special Meeting, the Merger Agreement, the Merger, and the issuance of Akebia Shares as the Merger Consideration is contained in this joint proxy statement/prospectus. This joint proxy statement/prospectus constitutes both a joint proxy statement of Keryx and Akebia and a prospectus of Akebia with respect to the Akebia Shares to be issued in connection with the Merger. It is a joint proxy statement because it will be used by both Keryx in soliciting proxies from the Keryx shareholders and by Akebia in soliciting proxies from the Akebia shareholders. It is a prospectus because Akebia, in connection with the Merger, is offering Akebia Shares in exchange for outstanding Keryx Shares, as described in further detail elsewhere in this joint proxy statement/prospectus.

The enclosed proxy materials allow you to submit a proxy by telephone or over the Internet, or by signing and returning the enclosed proxy card in the postage-paid envelope provided, without attending the applicable company’s special meeting in person.

Your vote is very important. You are encouraged to submit your proxy as soon as possible by telephone or over the Internet, or by signing and returning the enclosed proxy card in the postage-paid envelope provided, even if you do plan to attend the Keryx Special Meeting or the Akebia Special Meeting in person.

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Akebia Shares will continue to be registered and subject to reporting obligations under the Securities Exchange Act of 1934, as amended (the “Exchange Act”), following the consummation of the Merger. Akebia Shares will continue to be listed on The Nasdaq Global Market and will trade under the current Akebia symbol, “AKBA,” following the Merger.

The current executive leadership team at Akebia is expected to continue to serve in the same roles in the combined company after the consummation of the Merger. Akebia’s current executive leadership team is as follows: Mr. Butler, Akebia’s President and Chief Executive Officer, Jason A. Amello, Akebia’s Senior Vice President, Chief Financial Officer and Treasurer, Michel Dahan, Akebia’s Senior Vice President, Chief Business Officer, Rita Jain, M.D., Akebia’s Senior Vice President, Chief Medical Officer, Nicole R. Hadas, Akebia’s Senior Vice President, General Counsel and Secretary, Karen Tubridy, Akebia’s Senior Vice President, Chief Development Officer, and Tamara Dillon, Akebia’s Senior Vice President, Human Resources.

Akebia: The Akebia Special Meeting will be held at 11 a.m. local time, on December 11, 2018, at the offices of Latham & Watkins LLP located at 200 Clarendon Street, Boston, Massachusetts 02116.

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Akebia: The Akebia Board has fixed October 22, 2018 as the record date for determining the Akebia shareholders who are entitled to notice of and to vote at the Akebia Special Meeting. If you were a holder of record of Akebia Shares as of 5:00 p.m. U.S. Eastern Time on October 22, 2018, you are entitled to receive notice of and to vote at the Akebia Special Meeting and any adjournments thereof.

Approval of the Keryx Merger Proposal is required for consummation of the Merger. Neither the approval of the Keryx Adjournment Proposal nor the approval of the Keryx Advisory Compensation Proposal is required for consummation of the Merger.

No other matters are intended to be brought before the Keryx Special Meeting by Keryx.

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Approval by Akebia shareholders of the Akebia Share Issuance Proposal is a condition to the consummation of the Merger. If the Akebia Share Issuance Proposal is not approved, the Merger will not be consummated. The approval of the Akebia Adjournment Proposal is not required for the consummation of the Merger.

No other matters are intended to be brought before the Akebia Special Meeting by Akebia.

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Akebia: Yes. Simultaneously with the execution of the Merger Agreement, Keryx entered into a voting agreement with Muneer A. Satter, Chairperson of the Akebia Board, (the “Akebia Voting Agreement”) pursuant to which Mr. Satter has agreed, among other things, to vote the Akebia Shares that he beneficially owns at the time such vote is taken in favor of the Akebia Proposals and against approval of any proposal

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made in opposition to, in competition with, or inconsistent with, the Merger Agreement or the Merger. As of the record date for the Akebia Special Meeting, Mr. Satter beneficially owns approximately 5% of the outstanding Akebia Shares.

You may also cast your vote in person at your respective company’s special meeting.

If your shares are held in “street name,” through a bank, broker, or other nominee, that institution will send you separate instructions describing the procedure for voting your shares. Please follow the voting instructions provided by your bank, broker, or other nominee. “Street name” shareholders or shareholders who wish to vote in person at the applicable company’s special meeting will need to obtain a “legal proxy” from their bank, broker, or other nominee.

Akebia: You are entitled to one vote for each Akebia Share that you owned as of 5:00 p.m. U.S. Eastern Time on the record date for the Akebia Special Meeting. As of 5:00 p.m. U.S. Eastern Time on the record date for the Akebia Special Meeting, 57,059,063 Akebia Shares were outstanding and entitled to vote at the Akebia Special Meeting.

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Akebia: If you transfer your Akebia Shares after the record date for the Akebia Special Meeting but before the Akebia Special Meeting, unless you provide the transferee of your Akebia Shares with a proxy, you will retain your right to vote at the Akebia Special Meeting.

Akebia will not issue stock certificates in respect of any Akebia Shares issued in connection with the Merger, except as required by law. Keryx shareholders who are entitled to receive the Merger Consideration will receive Akebia Shares in book-entry form.

Akebia: The presence of Akebia shareholders entitled to cast a majority of all votes entitled to be cast by the holders of all outstanding Akebia Shares entitled to vote, in person or represented by proxy, is necessary to constitute a quorum at the Akebia Special Meeting. Abstentions will be counted as present and entitled to vote for purposes of determining a quorum. If your Akebia Shares are held in the name of a bank, broker, or other nominee, you must provide your bank, broker, or other nominee with instructions on how to vote your

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Akebia Shares. If you do not provide voting instructions for any of the Akebia Proposals, your Akebia Shares will not be voted on any Akebia Proposal, as your bank, broker, or other nominee will not have discretionary voting authority with respect to any of the Akebia Proposals and your Akebia Shares will not be counted as present and entitled to vote for purposes of determining a quorum.

A “broker non-vote” occurs when a broker submits a proxy that states that the broker votes for at least one proposal, but does not vote for proposals on non-routine matters because the broker has not received instructions from the beneficial owner on how to vote and does not have discretionary authority to vote on those proposals. Under the rules of The Nasdaq Stock Market LLC (“Nasdaq”), brokers do not have discretionary authority to vote on non-routine matters. Because all of the matters to be considered at the Keryx Special Meeting and the Akebia Special Meeting are non-routine and brokers will not have discretionary authority to vote on any of the Akebia Proposals or the Keryx Proposals, Akebia and Keryx do not expect to receive any broker non-votes, and shares for which voting instructions are not provided to the broker will not be deemed voting power present for any matter before the meeting, resulting in such shares being excluded from the calculation of quorum.

If you are a Keryx shareholder and you do not instruct your bank, broker, or other nominee on how to vote your shares on any of the Keryx Proposals:

If you are an Akebia shareholder and you do not instruct your bank, broker, or other nominee on how to vote your shares on any of the Akebia Proposals:

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Keryx Merger Proposal: If you are a Keryx shareholder and you fail to vote (i.e., fail to submit a proxy card or vote in person) or fail to return a voting instruction card instructing your bank, broker, or other nominee how to vote on the Keryx Merger Proposal, or if you respond with an “abstain” vote on the Keryx Merger Proposal, this will have the same effect as a vote cast “AGAINST” the Keryx Merger Proposal.

Keryx Adjournment Proposal and Keryx Advisory Compensation Proposal: If you are a Keryx shareholder and you fail to vote (i.e., fail to submit a proxy card or vote in person) or fail to return a voting instruction card instructing your bank, broker, or other nominee how to vote on the Keryx Adjournment Proposal and the Keryx Advisory Compensation Proposal, this will have no effect on the vote count for the Keryx Adjournment Proposal or the Keryx Advisory Compensation Proposal. If you are a Keryx shareholder and you respond with an “abstain” vote on the Keryx Adjournment Proposal or the Keryx Advisory Compensation Proposal, this will have the same effect as a vote cast “AGAINST” the Keryx Adjournment Proposal or the Keryx Advisory Compensation Proposal, respectively.

Akebia Quorum: If you are an Akebia shareholder and you fail to vote (i.e., fail to submit a proxy card or vote in person) or fail to properly instruct your bank, broker, or other nominee how to vote with respect to any of the Akebia Proposals, your Akebia Shares will not count towards determining whether a quorum is present. However, if you respond with an “abstain” vote on any of the Akebia Proposals, or vote on one or more of the Akebia Proposals, your Akebia Shares will count towards determining whether a quorum is present.

Akebia Proposals: If you are an Akebia shareholder and you fail to vote (i.e., fail to submit a proxy card or vote in person) or fail to return a voting instruction card instructing your bank, broker, or other nominee how to vote, or if you respond with an “abstain” vote on the Akebia Proposals, this will have no effect on the outcome of the Akebia Proposals.

An abstention occurs when a holder attends the applicable meeting in person and does not vote (assuming that such holder did not previously authorize a proxy) or returns a proxy or voting instruction card with an “abstain” vote.

Please note that if you sign and return your proxy or voting instruction card without indicating how to vote on any particular proposal (and you do not change your vote after delivering your proxy or voting instruction card), the Keryx Shares represented by your proxy will be voted “FOR” each Keryx Proposal in accordance with the recommendation of the Keryx Board, or the Akebia Shares represented by your proxy will be voted “FOR” each Akebia Proposal in accordance with the recommendation of the Akebia Board, as applicable. See the Q&A below entitled “May I change my vote after I have delivered my proxy or voting instruction card?” for further information on how to change your vote.

Your vote is very important. Whether or not you plan to attend the Keryx Special Meeting or the Akebia Special Meeting, as applicable, please promptly complete and return the enclosed proxy card or submit your proxy by telephone or through the Internet.

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Attending the Keryx Special Meeting will not automatically revoke a proxy that was submitted through the Internet or by telephone or mail. If you wish to change your vote at the Keryx Special Meeting, you must vote by ballot at such meeting or if you wish to revoke your vote at the Keryx Special Meeting, you must bring a written notice of revocation to the Secretary of the Keryx Special Meeting prior to the voting at the Keryx Special Meeting.

If you are a Keryx shareholder whose shares are held in “street name” by a bank, broker, or other nominee, you may revoke your proxy and vote your Keryx Shares in person at the Keryx Special Meeting only in accordance with applicable rules and procedures as employed by such bank, broker, or other nominee. If your Keryx Shares are held in an account at a bank, broker, or other nominee, you should contact your bank, broker, or other nominee to change your vote.

Akebia: If you are an Akebia shareholder of record, you may change your vote or revoke a proxy at any time before your proxy is voted at the Akebia Special Meeting. You can do this by:

Attending the Akebia Special Meeting will not automatically revoke a proxy that was submitted through the Internet or by telephone or mail. If you wish to change your vote at the Akebia Special Meeting, you must vote by ballot at such meeting or if you wish to revoke your vote at the Akebia Special Meeting, you must bring a written notice of revocation to the Secretary of the Akebia Special Meeting prior to the voting of the Akebia Special Meeting.

If you are an Akebia shareholder whose shares are held in “street name” by a bank, broker, or other nominee, you may revoke your proxy and vote your Akebia Shares in person at the Akebia Special Meeting only in accordance with applicable rules and procedures as employed by such bank, broker, or other nominee. If your shares are held in an account at a bank, broker, or other nominee, you should contact your bank, broker, or other nominee to change your vote.

Keryx has engaged Georgeson LLC (“Georgeson”) to assist in the solicitation of proxies for the Keryx Special Meeting, and Keryx estimates it will pay Georgeson a fee of $12,500, plus reimbursement for reasonable and documented out-of-pocket expenses and disbursements incurred in connection with the proxy solicitation. Keryx has also agreed to indemnify Georgeson against certain losses, costs, and expenses. In addition to mailing proxy solicitation material, Keryx’s directors, officers, and employees may also solicit proxies in person, by telephone, or by any other electronic means of communication deemed

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appropriate. No additional compensation will be paid to Keryx’s directors, officers or employees for such services.

Akebia has engaged MacKenzie Partners, Inc. (“MacKenzie”) to assist in the solicitation of proxies for the Akebia Special Meeting, and Akebia estimates it will pay MacKenzie a fee of approximately $40,000, plus reimbursement for reasonable and documented out-of-pocket expenses and disbursements incurred in connection with the proxy solicitation. Akebia has also agreed to indemnify MacKenzie against certain losses, costs, and expenses. In addition to mailing proxy solicitation material, Akebia’s directors, officers, and employees may also solicit proxies in person, by telephone or by any other electronic means of communication deemed appropriate. No additional compensation will be paid to Akebia’s directors, officers, or employees for such services.

At the Akebia Special Meeting, Broadridge Financial Solutions, Inc. (“Broadridge”) will serve as inspector of elections, count all of the proxies or ballots submitted and report the votes at the Akebia Special Meeting. Whether you submit your proxy by accessing the Internet, telephone or mail, your proxy will be received directly by Broadridge.

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Please review the information set forth in the section entitled “Material U.S. Federal Income Tax Consequences”, which constitutes the opinion of Goodwin Procter LLP, beginning on page 136 of this joint proxy statement/prospectus for a more complete description of the material U.S. federal income tax consequences of the Merger. The tax consequences to you of the Merger will depend on your particular facts and circumstances. Please consult your tax advisors as to the specific tax consequences to you of the Merger.

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SELECTED HISTORICAL CONSOLIDATED FINANCIAL DATA OF KERYX

Set forth below are selected historical consolidated financial data for Keryx. The financial data as of December 31, 2017 and 2016 and for the years ended December 31, 2017, 2016 and 2015 are derived from Keryx’s audited financial statements and related notes that are incorporated by reference into this joint proxy statement/prospectus from Keryx’s Annual Report on Form 10-K for the year ended December 31, 2017. The financial data as of December 31, 2015, 2014 and 2013 and for the years ended December 31, 2014 and 2013 are derived from the audited financial statements of Keryx that are not included in or incorporated by reference into this joint proxy statement/prospectus.

The selected historical consolidated financial data as of June 30, 2018 and for the three and six months ended June 30, 2018 and June 30, 2017 are derived from Keryx’s unaudited financial statements and related notes that are incorporated by reference into this joint proxy statement/prospectus from Keryx’s Quarterly Report on Form 10-Q for the period ended June 30, 2018. The selected historical consolidated financial data of Keryx as of June 30, 2017 are derived from Keryx’s unaudited consolidated financial statements and related notes from Keryx’s Quarterly Report on Form 10-Q for the period ended June 30, 2017, which is not incorporated by reference into this joint proxy statement/prospectus. Keryx’s management believes that Keryx’s unaudited consolidated financial statements have been prepared on a basis consistent with its audited financial statements and include all normal and recurring adjustments necessary for a fair presentation of the results for each interim period.

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The information set forth below is only a summary and it is not necessarily indicative of the results of future operations of Keryx, nor does it include the effects of the Merger. Interim results for the six months ended and as of June 30, 2018 are not necessarily indicative of, and are not projections for, the results to be expected for the fiscal year ended December 31, 2018. The selected historical consolidated financial statement data provided below is only a summary, and you should read it in conjunction with the audited consolidated financial statements of Keryx and the related notes contained in its Annual Report on Form 10-K for the year ended December 31, 2017, the unaudited consolidated financial statements and related notes contained in the Quarterly Report on Form 10-Q for the period ended June 30, 2018, and the other information that Keryx has previously filed with the SEC and which is incorporated into this joint proxy statement/prospectus by reference. See “Incorporation of Certain Documents by Reference” and “Where You Can Find More Information” beginning on pages 185 and 186, respectively, of this joint proxy statement/prospectus.

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SELECTED HISTORICAL CONSOLIDATED FINANCIAL DATA OF AKEBIA

Set forth below are selected historical consolidated financial data for Akebia. The financial data as of December 31, 2017 and 2016 and for the years ended December 31, 2017, 2016, and 2015 are derived from Akebia’s audited financial statements and related notes that are incorporated by reference into this joint proxy statement/prospectus from Akebia’s Annual Report on Form 10-K for the year ended December 31, 2017. The financial data as of December 31, 2015, 2014, and 2013 and for the years ended December 31, 2014 and December 31, 2013 are derived from the audited financial statements of Akebia that are not included in or incorporated by reference into this joint proxy statement/prospectus.

The selected historical consolidated financial data as of June 30, 2018 and for the three and six months ended June 30, 2018 and June 30, 2017 are derived from Akebia’s unaudited financial statements and related notes that are incorporated by reference into this joint proxy statement/prospectus from Akebia’s Quarterly Report on Form 10-Q for the period ended June 30, 2018. The selected historical consolidated financial data of Akebia as of June 30, 2017 are derived from Akebia’s unaudited consolidated financial statements and related notes from Akebia’s Quarterly Report on Form 10-Q for the period ended June 30, 2017, which is not incorporated by reference into this joint proxy statement/prospectus. Akebia management believes that Akebia’s unaudited consolidated financial statements have been prepared on a basis consistent with its audited financial statements and include all normal and recurring adjustments necessary for a fair presentation of the results for each interim period.

The information set forth below is only a summary and it is not necessarily indicative of the results of future operations of Akebia, nor does it include the effects of the Merger. Interim results for the six months ended and as of June 30, 2018 are not necessarily indicative of, and are not projections for, the results to be expected for the fiscal year ended December 31, 2018.

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The selected historical consolidated financial statement data provided below is only a summary, and you should read it in conjunction with the audited consolidated financial statements of Akebia and the related notes contained in its Annual Report on Form 10-K for the year ended December 31, 2017, the unaudited consolidated financial statements and related notes contained in the Quarterly Report on Form 10-Q for the period ended June 30, 2018, and the other information that Akebia has previously filed with the SEC and which is incorporated into this joint proxy statement/prospectus by reference. See “Incorporation of Certain Documents by Reference” and “Where You Can Find More Information” beginning on pages 185 and 186, respectively, of this joint proxy statement/prospectus.

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SELECTED AKEBIA AND KERYX UNAUDITED PRO FORMA

CONDENSED COMBINED FINANCIAL DATA

The following selected unaudited pro forma condensed combined financial data (the “selected pro forma data”) give effect to the Merger. The selected unaudited pro forma combined statements of operations and comprehensive loss data for the year ended December 31, 2017 and the six months ended June 30, 2018, give effect to the Merger under the acquisition method of accounting, as if the Merger had occurred on January 1, 2017. The selected unaudited pro forma combined balance sheet data as of June 30, 2018 gives effect to the Merger under the acquisition method of accounting, as if the Merger had occurred on June 30, 2018, assuming each outstanding Keryx Share, Keryx Restricted Shares, and the Keryx Options had become Akebia Shares, Akebia RSUs, or options to acquire Akebia Shares, respectively, based on the Exchange Multiplier.

The historical consolidated financial information has been adjusted in the selected pro forma data to give effect to pro forma events that are (i) directly attributable to the Merger, (ii) factually supportable and (iii) with respect to the statements of income, expected to have a continuing impact on Akebia’s results after the Merger.

The selected pro forma data have been derived from, and should be read in conjunction with, the more detailed unaudited pro forma combined financial information of Akebia following the Merger appearing elsewhere in this joint proxy statement/prospectus and the accompanying notes to the unaudited pro forma combined financial information. In addition, the selected pro forma data were based on, and should be read in conjunction with, the following historical consolidated financial statements and accompanying notes, which are incorporated by reference into this joint proxy statement/prospectus:

The selected pro forma data have been prepared by Akebia using the acquisition method of accounting in accordance with the Financial Accounting Standards Board, Accounting Standards Codification (“ASC”) 805, Business Combinations, and uses the fair value concepts defined in ASC 820, Fair Value Measurements and Disclosures, which Akebia has adopted as required. Akebia has been treated as the acquirer in the Merger for accounting purposes. Acquisition accounting requires, among other things, that most assets acquired and liabilities assumed be recognized at their fair values as of the acquisition date. Fair value measurements recorded in acquisition accounting are dependent upon certain valuation studies of Keryx’s assets and liabilities and other studies that have yet to commence or progress to a stage where there is sufficient information for a definitive measurement. Accordingly, the pro forma adjustments reflect the assets and liabilities of Keryx at their preliminary estimated fair values which use assumptions that Akebia believes are reasonable based on information that is currently available to it. Differences between these preliminary estimates and the final acquisition accounting will occur, and those differences could have a material impact on the selected pro forma data. The pro forma adjustments are preliminary and have been made solely for the purpose of providing unaudited pro forma condensed combined financial information prepared in accordance with the rules and regulations of the SEC.

The selected pro forma data have been presented for informational purposes only. The selected pro forma data do not purport to represent the actual results of operations that Akebia and Keryx would have achieved had the companies been combined during the periods presented in the selected financial data and is not intended to project the future results of operations that Akebia may achieve after the Merger is consummated.

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The selected pro forma data do not reflect any cost savings that may be realized as a result of the Merger and also do not reflect any restructuring or integration-related costs to achieve those potential cost savings.

Amounts below are presented in thousands, except per share amounts.

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COMPARATIVE HISTORICAL AND UNAUDITED PRO FORMA PER SHARE DATA

The following table sets forth selected historical and unaudited pro forma combined per share information for Akebia and Keryx.

Historical Per Share Information of Akebia and Keryx. The historical per share information of each of Akebia and Keryx below is derived from the audited consolidated financial statements of each of Akebia and Keryx as of, and for the year ended, December 31, 2017 and the unaudited consolidated financial statements of each of Akebia and Keryx as of, and for the six months ended, June 30, 2018.

Unaudited Pro Forma Combined per Share Data of Akebia. The unaudited pro forma combined per share data of Akebia set forth below gives effect to the Merger under the acquisition method of accounting, as if the Merger had been effective on January 1, 2017, the first day of Akebia’s fiscal year ended December 31, 2017, in the case of net income per share.

The unaudited pro forma combined per share data of Akebia is derived from the audited consolidated financial statements of each of Akebia and Keryx as of, and for the year ended, December 31, 2017, and the unaudited consolidated financial statements of each of Akebia and Keryx as of, and for the six months ended, June 30, 2018.

The acquisition method of accounting is based on Financial Accounting Standards Board, ASC 805, Business Combinations, and uses the fair value concepts defined in ASC 820, Fair Value Measurements and Disclosures, which Akebia has adopted as required. Acquisition accounting requires, among other things, that most assets acquired and liabilities assumed be recognized at their fair values as of the acquisition date. Fair value measurements recorded in acquisition accounting are dependent upon certain valuation studies of Keryx’s assets and liabilities and other studies that have yet to commence or progress to a stage where there is sufficient information for a definitive measurement. Accordingly, the pro forma adjustments reflect the assets and liabilities of Keryx at their preliminary estimated fair values. Differences between these preliminary estimates and the final values in acquisition accounting will occur and these differences could have a material impact on the unaudited pro forma combined per share information set forth in the following table.

The unaudited pro forma combined per share data of Akebia does not purport to represent the actual results of operations that Akebia would have achieved had the companies been combined during these periods or to project the future results of operations that Akebia may achieve after consummation of the Merger.

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Generally. You should read the below information in conjunction with the selected historical consolidated financial information included elsewhere in this joint proxy statement/prospectus and the historical consolidated financial statements of Akebia and Keryx and related notes that have been filed with the SEC, certain of which are incorporated by reference into this joint proxy statement/prospectus. See “Selected Historical Consolidated Financial Data of Akebia,” “Selected Historical Consolidated Financial Data of Keryx” and “Where You Can Find More Information” beginning on pages 31, 28, and 186, respectively, of this joint proxy statement/prospectus. The unaudited pro forma combined per share data of Akebia is derived from, and should be read in conjunction with, the Akebia and Keryx unaudited pro forma condensed combined financial statements and related notes included in this joint proxy statement/prospectus. See “Akebia and Keryx Unaudited Pro Forma Condensed Combined Financial Statements” beginning on page 156 of this joint proxy statement/prospectus.

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COMPARATIVE PER SHARE MARKET PRICE AND DIVIDEND INFORMATION

Market Prices

The principal trading market of Akebia Shares is The Nasdaq Global Market and the principal trading market of Keryx Shares is The Nasdaq Capital Market. The following table sets forth, for the calendar periods indicated, the high and low sales prices per Akebia Share and per Keryx Share as reported by The Nasdaq Global Market and The Nasdaq Capital Market, respectively. Akebia Shares are traded under the symbol “AKBA,” and Keryx Shares are traded under the symbol “KERX.”

The following table sets forth the closing sale prices per Akebia Share and per Keryx Share as reported on The Nasdaq Global Market and The Nasdaq Capital Market, respectively, as of June 27, 2018, the last trading day before the public announcement of the Merger Agreement, and as of October 26, 2018, the latest practicable date before the filing of this joint proxy statement/prospectus. The table also shows the implied value of the Merger Consideration per Keryx Share on each of the dates, which has been determined by multiplying the closing price of an Akebia Share on each of the dates by the 0.37433 Exchange Multiplier.

The market prices of Akebia Shares and Keryx Shares have fluctuated since the date of the announcement of the Merger Agreement and will continue to fluctuate from the date of this joint proxy statement/prospectus to the date of the Akebia Special Meeting and the Keryx Special Meeting and the date the Merger is consummated and thereafter. No assurance can be given concerning the market prices of Akebia Shares or Keryx Shares before consummation of the Merger or Akebia Shares after consummation of the Merger.

Holders

As of 5:00 p.m. U.S. Eastern Time on the record date for the Akebia Special Meeting, 57,059,063 Akebia Shares, held by 21 holders of record, were outstanding and entitled to vote at the Akebia Special Meeting. As of 5:00 p.m. U.S. Eastern Time on the record date for the Keryx Special Meeting, 120,375,926 Keryx Shares, held by 42 holders of record, were outstanding and entitled to vote at the Keryx Special Meeting.

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RISK FACTORS

In addition to the other information contained in or incorporated by reference into this joint proxy statement/prospectus, including the matters addressed under “Cautionary Statement Regarding Forward-Looking Statements” of this joint proxy statement/prospectus, Akebia shareholders should carefully consider the following risks in deciding whether to vote for the approval of the Akebia Proposals, and Keryx shareholders should carefully consider the following risks in deciding whether to vote for the approval of the Keryx Proposals. Descriptions of some of these risks can be found in the Quarterly Report for Akebia on Form 10-Q for the period ended June 30, 2018 and the Quarterly Report for Keryx on Form 10-Q for the period ended June 30, 2018, and any amendments thereto, as such risks may be updated or supplemented in each company’s subsequently filed Quarterly Reports on Form 10-Q or Current Reports on Form 8-K, and other filings with the SEC from time to time, which are incorporated by reference into this joint proxy statement/prospectus. You should read carefully this entire joint proxy statement/prospectus and its annexes and exhibits and the other documents incorporated by reference into this joint proxy statement/prospectus. See also “Incorporation of Certain Documents by Reference” and “Where You Can Find More Information” beginning on pages 185 and 186, respectively, of this joint proxy statement/prospectus.

Risks Related to the Merger

Fluctuations in the market price of Akebia Shares will affect the value of the Merger Consideration.

In connection with the closing of the Merger, each Keryx Share issued and outstanding immediately prior to the Effective Time will become the right to receive 0.37433, or the Exchange Multiplier, of Akebia Shares (plus cash in lieu of fractional shares). This Exchange Multiplier will not be adjusted in the event of any change in the market price of Akebia Shares or Keryx Shares and as a result, prior to the Effective Time, Keryx shareholders and Akebia shareholders cannot be sure of the value of the Akebia Shares to be issued in connection with the Merger. Based on the closing price per share of Akebia Shares on The Nasdaq Global Market on October 26, 2018, the latest practicable date before the filing of this joint proxy statement/prospectus, the 0.37433 of an Akebia Share that the holders of Keryx Shares will hold immediately following the Effective Time in respect of each Keryx Share they held immediately prior to the Effective Time would have a value of approximately $3.02.

The exact dollar value of the Akebia Shares that the Akebia shareholders and the Keryx shareholders will hold upon consummation of the Merger will not be known at the time of the Akebia Special Meeting or the Keryx Special Meeting and may be greater than, the same as or less than the current market prices of Akebia Shares at the time of the Akebia Special Meeting or the Keryx Special Meeting. The market price of the Akebia Shares is subject to general price fluctuations in the market for publicly traded equity securities and has experienced volatility in the past and may vary significantly from the dates of the Akebia Special Meeting and the Keryx Special Meeting. As a result of these fluctuations, the value of the Merger Consideration will also vary. For example, based on the range of closing prices of Akebia Shares during the period from June 27, 2018, the last trading day before public announcement of the Merger, through October 26, 2018, the latest practicable trading date before the filing of this joint proxy statement/prospectus, the Exchange Multiplier represented a value ranging from a low of $2.74 to a high of $4.06 for each Keryx Share.

Stock price changes may result from a variety of factors, including general market, industry and economic conditions, changes in the respective businesses, operations and prospects of Keryx and Akebia, regulatory considerations, results of the Keryx Special Meeting and the Akebia Special Meeting, announcements with respect to the Merger or any of the foregoing, and other factors beyond the control of Keryx or Akebia. You should obtain current market price quotations for Keryx Shares and for Akebia Shares, but as indicated above, the prices at the time the Merger is consummated may be greater than, the same as or less than such price quotations.

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The Merger may not be consummated unless important conditions are satisfied or waived and there can be no assurance that the Merger will be consummated.

The Merger Agreement contains a number of conditions that must be satisfied or waived (to the extent permitted by applicable law) to consummate the Merger. Those conditions include, among others:

These conditions to the consummation of the Merger may not be satisfied or waived (to the extent permitted by applicable law) and, as a result, the Merger may not be consummated at the time expected, or at all. For additional information regarding the conditions to the Merger, see “The Merger Agreement—Conditions to Consummation of the Merger” beginning on page 141 of this joint proxy statement/prospectus.

In addition, Keryx or Akebia may elect to terminate the Merger Agreement in certain other circumstances. See “The Merger Agreement—Termination of the Merger Agreement” beginning on page 152 of this joint proxy statement/prospectus.

The Merger Agreement contains provisions that could discourage a potential competing acquirer of either Keryx or Akebia.

The Merger Agreement contains “no shop” provisions that restrict each of Akebia’s and Keryx’s ability to solicit, initiate or knowingly encourage and induce, or take any other action designed to facilitate competing third-party proposals relating to a merger, reorganization or consolidation of the company or an acquisition of the company’s stock or assets. In addition, the other party generally has an opportunity to offer to modify the terms of the Merger in response to any competing acquisition proposals before the board of directors of the company that has received a third-party proposal may withdraw or qualify its recommendation with respect to the Merger. If the Merger Agreement is terminated in connection with the pursuit of a third-party transaction by one of the parties, that party will be required to pay a termination fee of $22 million to the other party. See “The Merger Agreement—No Solicitation,” “The Merger Agreement—Termination of the Merger Agreement” and “The Merger Agreement—Termination Fees and Expenses” beginning on pages 147, 152, and 153, respectively, of this joint proxy statement/prospectus.

These provisions could discourage a potential third-party acquirer that might have an interest in acquiring all or a significant portion of Akebia or Keryx from considering or proposing an acquisition, even if it were prepared to pay consideration with a higher per share cash or market value than the market value proposed to be received or realized in the Merger. A potential third-party acquirer maintaining interest in the face of these provisions might propose to pay a lower price to the shareholders than it might otherwise have proposed to pay because of the added expense of the $22 million termination fee that may become payable in certain circumstances.

If the Merger Agreement is terminated and either Akebia or Keryx determines to seek another business combination, it may not be able to negotiate a transaction with another party on terms comparable to, or better than, the terms of the Merger.

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The pendency of the Merger could materially adversely affect the business, financial condition, results of operations or cash flows of Keryx or Akebia.

The announcement and pendency of the Merger could disrupt Keryx’s or Akebia’s businesses, in any of the following ways, among others:

These disruptions could be exacerbated by a delay in the completion of the Merger or termination of the Merger Agreement. Additionally, if the Merger is not consummated, each company will have incurred significant costs and diverted the time and attention of management. A failure to consummate the Merger may also result in negative publicity, reputational harm, litigation against Keryx or Akebia or their respective directors and officers, and a negative impression of the companies in the financial markets. The occurrence of any of these events individually or in combination could have a material adverse effect on either or both companies’ financial statements and stock price.

In addition, the Merger Agreement restricts Akebia and Keryx from taking certain actions until the Effective Time without the consent of the other party, including, among others: the payment of dividends; the issuance of equity (including certain equity incentive awards); certain increases to employee compensation and benefits; capital expenditures; the incurrence of indebtedness; acquisitions and divestitures; and the entry into or amending certain material contracts. Akebia and Keryx are required to conduct business in the ordinary course consistent with past practice. The restrictive covenants, which are subject to various specific exceptions, may prevent Akebia or Keryx from pursuing attractive business opportunities that may arise prior to the consummation of the Merger. Although Akebia and Keryx may be able to pursue such activities with the other company’s consent, the other company may not be willing to provide its consent. For a description of the restrictive covenants applicable to Akebia and Keryx, see “The Merger Agreement—Conduct of Business Pending the Merger” beginning on page 144 of this joint proxy statement/prospectus.

Litigation filed or that may be filed against Keryx, Akebia, Merger Sub and/or the members of the Keryx Board or the Akebia Board could prevent or delay the consummation of the Merger.

Two putative shareholder class action lawsuits and one additional putative shareholder lawsuit have been filed by Keryx shareholders challenging the disclosures made in connection with the Merger. The lawsuits seek to enjoin the Merger, to recover damages if the Merger is consummated, attorneys’ fees, and other relief. Additional lawsuits arising out of the Merger may be filed in the future. For a more detailed description of litigation in connection with the Merger, see “The Merger—Litigation Relating to the Merger” beginning on page 136 of this joint proxy statement/prospectus.

The outcome of these lawsuits or any other lawsuit that may be filed challenging the Merger is uncertain. One of the conditions to the closing of the Merger is that no governmental authority has issued or entered any

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order after the date of the Merger Agreement having the effect of enjoining or otherwise prohibiting the consummation of the Merger. Accordingly, if these lawsuits or any future lawsuit is successful in obtaining any order enjoining consummation of the Merger, then such order may prevent the Merger from being consummated, or from being consummated within the expected time frame, and could result in substantial costs to Keryx and Akebia, including but not limited to, costs associated with the indemnification of directors and officers. Any such injunction or delay in the Merger being completed may adversely affect Keryx’s or Akebia’s business, financial condition, results of operations, and cash flows.

Keryx directors and executive officers and Akebia directors and executive officers have interests in the Merger that may be different from, or in addition to, the interests of Keryx shareholders and Akebia shareholders.

Certain of the directors and executive officers of Keryx and certain of the directors and executive officers of Akebia negotiated the terms of the Merger Agreement and these individuals have interests in the Merger that may be different from, or in addition to, those of Keryx shareholders and Akebia shareholders, respectively. These interests include, but are not limited to, the continued service of certain of these individuals as directors and executive officers of Akebia after the date of the consummation of the Merger (the “Closing Date”), the treatment in the Merger of Keryx Restricted Shares, Keryx Options and certain other compensation arrangements with the Keryx and Akebia directors and executive officers, and provisions in the Merger Agreement regarding continued indemnification of and advancement of expenses of the directors and executive officers of Keryx and Akebia. Keryx shareholders and Akebia shareholders should be aware of these interests when they consider their respective Boards of Directors’ recommendations that they vote in favor of the Merger-related proposals.

The members of the Keryx Board were aware of and considered these interests relating to Keryx, among other matters, in evaluating the Merger Agreement and the Merger, and in recommending that Keryx shareholders approve the Keryx Proposals. The interests of Keryx directors and executive officers are described under “The Merger—Interests of Keryx’s Directors and Executive Officers in the Merger” beginning on page 126 of this joint proxy statement/prospectus.

The members of the Akebia Board were aware of and considered these interests relating to Akebia, among other matters, in evaluating the Merger Agreement and the Merger, and in recommending that Akebia shareholders approve the Akebia Proposals. The interests of Akebia directors and executive officers are described in more detail under “The Merger—Interests of Akebia’s Directors and Executive Officers in the Merger” beginning on page 132 of this joint proxy statement/prospectus.

Following the consummation of the Merger, the composition of the board of directors and management of the combined company will be different from the composition of the current board of directors and management of each of Akebia and Keryx and Akebia’s current shareholders will not have a majority ownership and voting interest in the combined company, which may affect the strategy and operations of the combined company.

Pursuant to the Merger Agreement, following the consummation of the Merger, the Combined Board will consist of (i) Mr. Butler, Mr. Canute, Ms. Smith, and another individual to be designated by the Akebia Board, who will be a director of the Akebia Board prior to the Effective Time and reasonably acceptable to Keryx, who will be the Continuing Directors; (ii) Mr. Enyedy, Dr. Gilman, Mr. Heffernan, Ms. Morrison, and Mr. Rogers, who will be the Keryx Board Designees; and (iii) the Additional Director, who will be designated by the Akebia Board and the Keryx Board prior to the Effective Time, who will serve as the Chairperson of the Combined Board as of the Effective Time.

As of the Effective Time, the Continuing Directors, the Keryx Board Designees, and the Additional Director will be allocated among three classes of directors as follows:

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At the Effective Time, Akebia will take all necessary action to cause Mr. Butler to continue as Chief Executive Officer of the combined company. In the event that Mr. Butler is not the Chief Executive Officer of Akebia immediately prior to the Effective Time, Akebia will select another individual reasonably acceptable to Keryx to be appointed as Chief Executive Officer of the combined company as of the Effective Time.

In addition to Mr. Butler, the remainder of Akebia’s current executive leadership team is expected to continue to serve in the same roles in the combined company after the consummation of the Merger. Akebia’s current executive leadership team also includes: Jason A. Amello, Akebia’s Senior Vice President, Chief Financial Officer, and Treasurer; Michel Dahan, Akebia’s Senior Vice President, Chief Business Officer; Rita Jain, M.D., Akebia’s Senior Vice President, Chief Medical Officer; Nicole R. Hadas, Akebia’s Senior Vice President, General Counsel, and Secretary; Karen Tubridy, Akebia’s Senior Vice President, Chief Development Officer; and Tamara Dillon, Akebia’s Senior Vice President, Human Resources.

This composition of the Combined Board may affect the combined company’s business strategy and operating decisions following the consummation of the Merger, as compared to those of Akebia and Keryx prior to the Merger. In addition, there can be no assurances that the Combined Board will function effectively as a team and that any differences or difficulties, should they arise, will not have an adverse effect on the combined company’s business or results after the Closing Date.

In addition, immediately following completion of the Merger and the issuance of the Akebia Shares to the Keryx shareholders at the Effective Time, Akebia’s current shareholders in the aggregate will not have a majority ownership and voting interest in the combined company, which may result in Akebia shareholders having less influence on the combined company’s management and policies. Akebia’s shareholders currently have the right to vote for the election of directors to Akebia’s Board of Directors and on other matters affecting Akebia. Immediately following completion of the Merger, based on the companies’ fully diluted market capitalizations as of the signing of the Merger Agreement and also taking into account the Additional Shares expected to be issued to Baupost in connection with the conversion under that certain Notes Conversion Agreement prior to consummation of the Merger, Akebia’s shareholders and Keryx’s shareholders are expected to own approximately 49.4% and 50.6%, respectively, of the combined company’s outstanding shares. As a result, current Akebia shareholders may have less influence on the combined company’s management and policies than they currently have.

The opinions of Keryx’s and Akebia’s financial advisors do not reflect changes in circumstances that may have occurred or that may occur between the signing of the Merger Agreement and the consummation of the Merger.

The opinion rendered to the Keryx Board by MTS Securities, and the opinions rendered to the Akebia Board by J.P. Morgan and Evercore, were provided in connection with, and at the time of, the Keryx and Akebia Boards’ respective evaluations of the Merger. These opinions were based on the respective financial analyses performed, which considered market and other conditions then in effect, and financial forecasts and other information made available to them, as of the date of their respective opinions, which may have changed, or may change, after the date of the opinions. Neither the Keryx Board nor the Akebia Board has obtained updated opinions from their respective financial advisors as of the date of this joint proxy statement/prospectus or as of any other date, nor does either expect to receive updated, revised or reaffirmed opinions prior to the consummation of the Merger. Changes in the operations and prospects of Keryx or Akebia, general market and economic conditions and other factors that may be beyond the control of Keryx or Akebia, and which changes

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were not taken into account by Keryx’s and Akebia’s financial advisors in rendering their respective opinions, may significantly alter the value of Keryx or Akebia or the prices of Keryx Shares or Akebia Shares by the time the Merger is consummated. The opinions do not speak as of the time the Merger will be consummated or as of any date other than the date of such opinions. Because there are no plans for Keryx’s and Akebia’s financial advisors to update their opinions, the opinions do not address the fairness of the Exchange Multiplier or the Merger Consideration, as applicable, from a financial point of view, at any time other than the time such opinions were issued, even though the Keryx Board’s recommendation that Keryx shareholders vote “FOR” the Keryx Proposals and the Akebia Board’s recommendation that Akebia shareholders vote “FOR” the Akebia Proposals are made as of the date of this joint proxy statement/prospectus. For a description of the opinions that the Keryx Board and the Akebia Board received from their respective financial advisors, see “The Merger—Opinion of Keryx’s Financial Advisor—MTS Securities, LLC,” “The Merger—Opinion of Akebia’s Financial Advisor—Evercore Group L.L.C.,” and “The Merger—Opinion of Akebia’s Financial Advisor—J.P. Morgan Securities LLC” beginning on pages 95, 112, and 118, respectively, of this joint proxy statement/prospectus.

Failure to consummate the Merger could negatively impact respective future stock prices, operations and financial results of Keryx and Akebia.

If the Merger is not consummated for any reason, Keryx and Akebia may be subjected to a number of material risks, including the following:

In addition to the above risks, Keryx or Akebia may be required, under certain circumstances, to pay a termination fee of up to $22 million to the other party, and in some cases reimburse the other party’s expenses up to $6 million, which may materially adversely affect Keryx’s or Akebia’s financial condition, as applicable. The business of Keryx or Akebia may be adversely impacted by the failure to pursue other beneficial opportunities due to the focus of Keryx and Akebia management on the Merger. A failure to consummate the Merger may also result in negative publicity, reputational harm, litigation against Keryx or Akebia or their respective directors and officers, and a negative impression of the companies in the financial markets.

If the Merger is not consummated, we cannot assure the Akebia shareholders or the Keryx shareholders that these risks will not materialize and will not materially adversely affect the business, financial results and stock price of the respective companies.

Keryx shareholders and Akebia shareholders will not be entitled to appraisal rights in the Merger.

Appraisal rights are statutory rights that, if applicable under law, enable shareholders to dissent from an extraordinary transaction, such as a merger, and to demand that the corporation pay the fair value for their shares

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as determined by a court in a judicial proceeding instead of receiving the consideration offered to shareholders in connection with the extraordinary transaction.

Under the DGCL § 262(b), shareholders do not have appraisal rights if the shares of stock they hold, as of the record date for determination of shareholders entitled to vote at the meeting of shareholders to act upon a merger, are either (i) listed on a national securities exchange or (ii) held of record by more than 2,000 holders. Notwithstanding the foregoing, appraisal rights are available if shareholders are required by the terms of the Merger Agreement to accept for their shares anything other than (a) shares of stock of the surviving corporation, (b) shares of stock of another corporation that will either be listed on a national securities exchange or held of record by more than 2,000 holders, (c) cash instead of fractional shares or (d) any combination of clauses (a) through (c).

Because Akebia Shares are listed on The Nasdaq Global Market, a national securities exchange, and are expected to continue to be so listed on the record date for the Akebia Special Meeting, Akebia shareholders will not be entitled to appraisal rights in the Merger with respect to their Akebia Shares. Similarly, Keryx Shares are listed on The Nasdaq Capital Market and are expected to continue to be so listed on the record date for the Keryx Special Meeting. Because holders of Keryx Shares will also receive Akebia Shares in the Merger and cash in lieu of fractional shares, holders of Keryx Shares will also not be entitled to appraisal rights in the Merger with respect to their Keryx Shares.

Financial projections regarding Keryx and Akebia may not prove accurate.

In connection with the Merger, Keryx and Akebia prepared and considered internal financial forecasts for Keryx and Akebia. These financial projections are based on several assumptions, including regarding future operating cash flows, expenditures and income of Keryx and Akebia, including benefits to be realized from the Merger. These financial projections were not prepared with a view to public disclosure, are subject to significant economic, competitive, industry and other uncertainties and may not be achieved in full, within projected timeframes or at all. The failure of Keryx or Akebia to achieve projected results could have a material adverse effect on the price of the Akebia Shares, the combined company’s financial position after the Closing Date, and the combined company’s ability to pay dividends, and/or pay dividends at or above the rate currently paid by Akebia or Keryx, following the consummation of the Merger.

The Merger may disrupt attention of Keryx management and Akebia management from ongoing business operations.

Each of Keryx and Akebia has expended, and expects to continue to expend, significant management resources to consummate the Merger. The attention of each company’s management may be diverted away from the day-to-day operations of the businesses of Keryx and Akebia, respectively, including implementing initiatives to improve performance, execution of existing business plans and pursuing other beneficial opportunities, in an effort to consummate the Merger. This diversion of management resources could disrupt Keryx’s or Akebia’s operations and may have an adverse effect on the respective businesses, financial conditions, results of operations and cash flows of the two companies or the combined company after the Closing Date.

The market price for Akebia Shares following completion of the Merger will continue to fluctuate and may be affected by factors different from those that historically have affected Akebia Shares and Keryx Shares.

Following the completion of the Merger, Akebia shareholders and Keryx shareholders will be shareholders in the combined company. Keryx’s business differs in important respects from that of Akebia and the combined company’s business will differ from that of Akebia and Keryx prior to the completion of the Merger. Accordingly, the results of operations of the combined company and the market price of Akebia Shares after the completion of the Merger may be affected by factors different from those currently affecting the independent

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results of operations of each of Akebia and Keryx. This joint proxy statement/prospectus describes the businesses of Keryx and Akebia and incorporates by reference important information regarding the businesses of Keryx and Akebia and also describes important factors to consider in connection with those businesses and the business of the combined company.

Risks Related to the Business of the Combined Company After the Merger

Combining the two companies may be more difficult, costly or time consuming than expected, and Akebia may not realize all of the anticipated benefits of the Merger.

Keryx and Akebia have operated and, until the consummation of the Merger, will continue to operate, independently. The success of the Merger will depend on, among other things, the combined company’s ability to integrate the businesses of Keryx and Akebia in a timely fashion. Additionally, the combined company may not be able to successfully achieve the level of cost savings, revenue enhancements and synergies that it expects. If the combined company is not able to successfully achieve these objectives, the anticipated benefits of the Merger may not be realized fully or at all or may take longer to realize than expected. In addition, failure to successfully integrate the businesses in the expected timeframe may adversely affect the combined company’s business, financial condition, results of operations or cash flows.

In addition, the combined operation of two businesses may be a complex, costly and time-consuming process. The difficulties of combining the operations of the companies include, among others:

Many of these factors are outside the control of Keryx and Akebia, and any one of them could result in increased costs, decreased expected revenues and diversion of management time and energy, which could materially impact the business, financial condition, results of operations and cash flows of the combined company. These factors could cause dilution to the earnings per share of the combined company, decrease or delay the expected accretive effect of the Merger and negatively impact the price of Akebia Shares. As a result, it cannot be assured that the combined company will realize the full benefits anticipated from the Merger within the anticipated time frames, or at all.

In addition, following the Merger, Akebia will become responsible for Keryx’s liabilities and obligations, including with respect to legal, financial, regulatory, and compliance matters. These obligations will result in

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additional cost and investment by Akebia and, if Akebia has underestimated the amount of these costs and investments or if Akebia fails to satisfy any such obligations, Akebia may not realize the anticipated benefits of the Merger. Further, it is possible that there may be unknown, contingent or other liabilities or problems that may arise in the future, the existence and/or magnitude of which Akebia was previously unaware. Any such liabilities or problems could have an adverse effect on the combined company’s business, financial condition, results of operations or cash flows.

Even if the Merger is successfully consummated and the businesses integrated, there can be no assurance that the Merger will result in the realization of the full benefit of the anticipated synergies and cost savings or that these benefits will be realized within the expected time frames or at all. Difficulties in integrating the businesses could harm the reputation of the combined company. In addition, by engaging in the Merger, Akebia may forego or delay pursuit of other opportunities that may have proven to have greater commercial potential.

Baupost, Keryx’s current largest shareholder, may have significant influence over the combined company following the Merger and may cause the combined company to take actions that may not be, or refrain from taking actions that may be, in the combined company’s best interest or the best interest of its other shareholders.

Baupost is the owner of approximately 21% of the outstanding Keryx Shares as of the record date for the Keryx Special Meeting. Pursuant to the Notes Conversion Agreement, Baupost is expected to convert all of the existing Convertible Notes it holds into Keryx Shares and receive the Additional Shares. Following Baupost’s conversion of the Convertible Notes and the issuance to Baupost of the Additional Shares, Baupost is expected to beneficially own approximately 40.9% of Keryx Shares. After consummation of the Merger, Baupost is expected to be the beneficial owner of approximately 20.7% of shares of the combined company. Baupost, through its equity interests, may have significant influence over matters submitted to shareholders of the combined company for approval and other corporate actions, such as:

Moreover, because large shareholders have potential power to direct or influence the combined company’s corporate actions, the combined company may be required to engage in transactions that may not be agreeable to or in the best interest of its other shareholders.

Keryx and Akebia will incur substantial direct and indirect costs as a result of the Merger and the combined company will incur substantial direct and indirect costs in connection with combining the business of Keryx and Akebia following the Merger.

Keryx and Akebia will incur substantial expenses in connection with and as a result of consummating the Merger, and over a period of time following the consummation of the Merger, Akebia also expects to incur substantial expenses as a combined company in connection with coordinating and, in certain cases, combining the businesses, operations, policies and procedures of Keryx and Akebia. A portion of the transaction costs related to the Merger will be incurred regardless of whether the Merger is consummated. While Keryx and

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Akebia have assumed that a certain level of transaction expenses will be incurred, factors beyond Keryx’s and Akebia’s control could affect the total amount or the timing of these expenses. Although many of the expenses that will be incurred, by their nature, are difficult to estimate accurately, the current estimate of the aggregate expenses that will be incurred by Keryx and Akebia is approximately $30.5 million, which is subject to change. These expenses may exceed the costs historically borne by Keryx and Akebia. These expenses could adversely affect the financial condition, results of operations and cash flows of the combined company following the consummation of the Merger.

Akebia’s actual financial position and results of operations after the Merger as a combined company may differ materially from the unaudited pro forma financial information included in this joint proxy statement/prospectus.

The unaudited pro forma financial information included in this joint proxy statement/prospectus is presented for informational purposes only and may not be an indication of what Akebia’s financial position or results of operations would have been had the Merger been consummated on the dates indicated. The unaudited pro forma financial information has been derived from the audited and unaudited historical financial statements of Akebia and Keryx and certain adjustments and assumptions regarding Akebia after giving effect to the Merger. The assets and liabilities of Keryx have been measured at fair value based on various preliminary estimates using assumptions that Akebia and Keryx management believes are reasonable, utilizing information currently available. These fair value measurements can be highly subjective and the reasonable application of measurement principles may result in a range of alternative estimates using the same facts and circumstances. These estimates, which require extensive use of accounting estimates and management judgment, may be revised as additional information becomes available and as additional analyses are performed. Differences between preliminary estimates in the unaudited pro forma financial information and the final acquisition accounting will occur and could have a material impact on the unaudited pro forma financial information and the combined company’s financial position and future results of operations.

Furthermore, during the preparation of the unaudited pro forma condensed combined financial statements, Akebia was aware of one material difference between Akebia’s accounting policies and the accounting policies of Keryx related to revenue recognition. As further described in Note 3, Akebia adopted ASC 606 using the full retrospective transition method, whereas Keryx adopted ASC 606 using the modified retrospective method. Following the Merger, the combined company will conduct a more detailed review of Keryx’s accounting policies in an effort to determine if differences in accounting policies require restatement or reclassification of results of operations or reclassification of assets or liabilities to conform to Akebia’s accounting policies and classifications. As a result of that review, the combined company may identify other differences among the accounting policies of the companies that, when conformed, could have a material impact on the unaudited pro forma condensed combined financial statements contained in this joint proxy statement/prospectus.

In addition, the assumptions used in preparing the unaudited pro forma financial information may not prove to be accurate, and other factors may affect the combined company’s financial condition or results of operations following the consummation of the Merger. Any material variance from the pro forma financial information may cause significant variations in the market price of the Akebia Shares. See “Akebia and Keryx Unaudited Pro Forma Condensed Combined Financial Statements” beginning on page 156 of this joint proxy statement/prospectus.

Sales of Akebia Shares after the completion of the Merger may cause the market price of Akebia Shares to fall.

Based on the number of outstanding Keryx Shares as of the record date for the Keryx Special Meeting, and assuming the issuance to Baupost of the Additional Shares and Keryx Shares issuable upon conversion of the Convertible Notes held by Baupost, Akebia would issue approximately 60 million Akebia Shares as Merger Consideration. Keryx shareholders may decide not to hold the Akebia Shares they receive in the Merger and other Keryx shareholders, such as funds with limitations on the amount of stock they are permitted hold in

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individual issuers, may be required to sell Akebia Shares that they receive in the Merger. Such sales, or market perception of such sales, of Akebia Shares could result in higher than average trading volume following the closing of the Merger and may cause the market price for Akebia Shares to decline. Such sales may take place promptly following the Merger or at other times in the future.

The Merger will be dilutive to Akebia’s earnings per share.

Because Akebia Shares will be issued in connection with the Merger, the Merger will be dilutive to Akebia’s earnings per share. Future events and conditions could increase the dilution that is currently projected, including adverse changes in market conditions, additional transaction and integration-related costs and other factors such as the failure to realize some or all of the benefits anticipated in the Merger. Any dilution of, or delay of any accretion to, Akebia’s earnings per share could cause the price of Akebia’s Shares to decline or grow at a reduced rate.

Akebia is expected to record goodwill and other intangible assets as a result of the Merger, and such goodwill and other intangible assets could become impaired in the future.

Accounting standards in the United States require that one party to the Merger be identified as the acquirer. In accordance with these standards, the Merger will be accounted for as an acquisition of Keryx Shares by Akebia and will follow the acquisition method of accounting for business combinations. The Akebia assets and liabilities will be consolidated with those of Keryx on Akebia’s financial statements. The combined company will measure Keryx’s assets acquired and liabilities assumed at their fair values, including net tangible and identifiable intangible assets acquired and liabilities assumed, as of the consummation of the Merger. The excess of the purchase price over the fair value of Keryx’s assets and liabilities will be recorded as goodwill. Akebia currently estimates that the Merger will add approximately $289.0 million of goodwill and other intangible assets.

In accordance with GAAP, the combined company will be required to periodically assess these assets to determine if they are impaired. To the extent goodwill or other intangible assets become impaired, the combined company may be required to incur material charges relating to such impairment. Such a potential impairment charge could have a material impact on future operating results and statements of financial position of the combined company.

If third parties, including the licensor of certain intellectual property relating to Keryx’s product, Auryxia, terminate, modify or threaten to terminate existing contracts or relationships with Akebia or Keryx, Akebia’s and Keryx’s respective businesses may be materially harmed.

Keryx has contracts with customers, suppliers, vendors, landlords, licensors and other business partners that may require Keryx to obtain consents from these other parties in connection with the Merger. If these consents cannot be obtained, the combined company may suffer a loss of potential future revenues and may lose rights that are material to the business of the combined company. In addition, third parties with whom Akebia or Keryx currently have relationships may terminate or otherwise reduce the scope of their relationship with either party in anticipation of the Merger. Any such disruptions could limit the combined company’s ability to achieve the anticipated benefits of the Merger. The adverse effect of such disruptions could also be exacerbated by a delay in the completion of the Merger or the termination of the Merger Agreement.

As more fully described in its public filings made with the SEC, Keryx has licensed and sublicensed certain intellectual property rights covering Auryxia from a third party, Panion & BF Biotech, Inc., or Panion, pursuant to the Amended and Restated License Agreement between Keryx and Panion. Panion has the right to terminate the license agreement upon, among other things, the occurrence of a breach of a material provision of the license agreement by Keryx that is not cured within ninety days of written notice. If the agreement is terminated, Keryx would lose certain intellectual property rights covering Auryxia.

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On September 21, 2018, Keryx notified Akebia that, following announcement of the Merger, Panion notified Keryx in writing that the license agreement would terminate on November 21, 2018 if Keryx did not cure the breach alleged by Panion, specifically, that Keryx failed to use commercially reasonable best efforts to commercialize Auryxia outside the United States. Keryx disagreed with Panion’s claims, and the parties entered discussions to resolve this dispute. On October 24, 2018, Keryx, Panion, and Akebia entered into a letter agreement (the “Panion Letter Agreement”), pursuant to which Panion agreed to rescind any and all prior termination threats or notices relating to the license agreement and waived its rights to terminate the license agreement based on any breach by Keryx of its obligation to use commercially reasonable efforts to commercialize Auryxia outside the United States until the parties execute an amendment to the license agreement in accordance with the terms of the Panion Letter Agreement following consummation of the Merger. These terms include establishing a joint steering committee consisting of Panion and Akebia representatives to oversee the development and commercialization of Fexeric^® in Europe and providing Panion with an exclusive license under Keryx-owned patents covering the rights to make, use, sell, offer for sale and import ferric citrate in certain countries in the Asia-Pacific region. The parties will agree on a regulatory plan for Fexeric in Europe within four months after execution of the Panion Letter Agreement. The parties will also agree on a commercialization plan for Fexeric in Europe following execution of the amendment. The amendment will include alternatives in the event a commercialization plan is not agreed upon, such as payment of an annual license maintenance fee to Panion or the return of European intellectual property rights to Panion. In addition, under the terms of the Panion Letter Agreement, Panion has agreed that Keryx will have the right, but not the obligation, to conduct any litigation against any infringer of patent rights under the license agreement on the terms agreed upon in the Panion Letter Agreement. Keryx also agreed to make a $500,000 payment to Panion promptly after execution of the Panion Letter Agreement. In the event the Merger is not consummated, Keryx and Panion are obligated to fulfill the terms of the Panion Letter Agreement, including negotiating in good faith an amendment to the license agreement.

Recent changes to reimbursement coverage for Keryx’s product, Auryxia, could have a material adverse effect on Auryxia sales and profitability.

In the United States, there are multiple governmental and private third party payors with varying coverage and reimbursement levels for pharmaceutical products. Within Medicare, for oral drugs dispensed by pharmacies and also administered in facilities, coverage and reimbursement may vary depending on the setting. The Centers for Medicare & Medicaid Services, or CMS, local Medicare administrative contractors and/or Medicare Part D plans may have some responsibility for determining the medical necessity of such drugs, and therefore coverage, for different patients. Different reimbursement methodologies may apply and CMS may have some discretion in interpreting their application in certain settings. For example, CMS recently communicated to Medicare Part D sponsors that Auryxia is considered by CMS as a covered Part D drug when it is used for its FDA-approved indication for the control of serum phosphorus levels. CMS also indicated that it does not consider Auryxia covered under Part D when it is used solely for the treatment of iron deficiency anemia in patients with chronic kidney disease not on dialysis, which is Auryxia’s other FDA-approved indication. As a result, CMS currently expects Part D sponsors to utilize a prior authorization edit (“PA”), or other process, for all Auryxia prescriptions for Medicare beneficiaries to ensure that Auryxia is being used for a Part D covered indication. Keryx expects Part D sponsors will implement a PA for Auryxia no later than January 2019. Keryx is engaging in discussions with CMS and Part D sponsors on this matter as Keryx believes that Auryxia should qualify for coverage under Part D under CMS regulations when it is used for the treatment of iron deficiency anemia in patients with chronic kidney disease not on dialysis.

While Keryx believes that the vast majority of the Part D prescriptions written for Auryxia today are for the control of serum phosphorus levels and therefore will continue to be covered by Part D plans, Keryx cannot predict the impact of these changes on Keryx’s operations and they could have a material adverse effect on Keryx’s results of operations going forward.

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Risks Related to Keryx’s Business

You should read and consider the risk factors specific to Keryx’s business that will also affect Akebia after the Merger. These risks are described in Part I, Item 1A of Keryx’s Annual Report on Form 10-K for the fiscal year ended December 31, 2017, and any amendments thereto, as such risks have been or may be updated or supplemented in Keryx’s subsequently filed Quarterly Reports on Form 10-Q or Current Reports on Form 8-K, and in other documents that are incorporated by reference into this joint proxy statement/prospectus. See “Incorporation of Certain Documents by Reference” and “Where You Can Find More Information” beginning on pages 185 and 186, respectively, of this joint proxy statement/prospectus.

Risks Related to Akebia’s Business

You should read and consider the risk factors specific to Akebia’s business that will also affect Akebia after the Merger. These risks are described in Part II, Item 1A of Akebia’s Quarterly Report on Form 10-Q for the period ended June 30, 2018, and any amendments thereto, as such risks have been or may be updated or supplemented in Akebia’s subsequently filed Quarterly Reports on Form 10-Q or Current Reports on Form 8-K, and in other documents that are incorporated by reference into this joint proxy statement/prospectus. See “Incorporation of Certain Documents by Reference” and “Where You Can Find More Information” beginning on pages 185 and 186, respectively, of this joint proxy statement/prospectus.

CAUTIONARY STATEMENT REGARDING FORWARD-LOOKING STATEMENTS

This joint proxy statement/prospectus contains certain forward-looking statements within the meaning of the federal securities law. Such statements are based upon current plans, estimates and expectations that are subject to various risks and uncertainties. The inclusion of forward-looking statements should not be regarded as a representation that such plans, estimates and expectations will be achieved. Words such as “anticipate,” “expect,” “project,” “intend,” “believe,” “may,” “will,” “should,” “plan,” “could,” “target,” “contemplate,” “estimate,” “position,” “predict,” “potential,” “opportunity” and words and terms of similar substance used in connection with any discussion of future plans, actions or events identify forward-looking statements. All statements, other than historical facts, including statements regarding the expected timing of the closing of the Merger; the ability of the parties to complete the Merger considering the various closing conditions; legal proceedings related to the Merger; the potential benefits of vadadustat; the expected timing of Akebia’s Otsuka funding option; the timing of availability of top-line results from clinical trials of vadadustat; the composition of the Combined Board; the assigned classes of the members of the Combined Board; the financial profile of the combined company following consummation of the Merger; the potential to establish a new standard of care; the expected timing of enrollment in clinical trials; revenue growth; the market opportunity, reimbursement coverage, commercial momentum and growth potential of Auryxia; the expected benefits of the Merger, such as efficiencies, the expected management team, cost savings and the expected timing thereof, synergies, the ability to deliver value, the potential to maximize sales, the ability to build launch momentum for vadadustat in the United States, enhanced revenues, growth potential, market profile, financial strength, and financial flexibility, the potential for accelerating profitability and reducing capital needs; the competitive ability and position of the combined company; the strategy of the combined company; the expected cash position of the combined company; and any assumptions underlying any of the foregoing, are forward-looking statements. Important factors that could cause actual results to differ materially from Akebia’s and Keryx’s plans, estimates or expectations could include, but are not limited to:

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