The following questions and answers are intended to address briefly some commonly asked questions regarding the Merger, the Merger Agreement and the Special Meeting. These questions and answers may not address all questions that may be important to you as a Company stockholder. Please refer to the “Summary” and the more detailed information contained elsewhere in this proxy statement, the annexes to this proxy statement and the documents referred to in this proxy statement, which you should read carefully and in their entirety. You may obtain the information incorporated by reference in this proxy statement without charge by following the instructions under “Where You Can Find More Information.”

If you properly sign your proxy card but do not mark the boxes showing how your shares should be voted on a matter, the shares represented by your properly signed proxy will be voted “FOR” approval of the Merger Proposal and “FOR” approval of the Adjournment Proposal.

This proxy statement, and the documents to which we refer you in this proxy statement, as well as oral statements made or to be made by us, contains forward-looking statements, including statements relating directly or indirectly to the timing or likelihood of completing the Merger, plans for future growth, changes in the business and other business development activities as well as capital expenditures, financing sources and the effects of regulation and competition and all other statements regarding our intent, plans, beliefs or expectations or those of our directors or officers. All statements included or incorporated by reference in this proxy statement, other than statements that are historical facts, are forward-looking statements. The words “believe,” “expect,” “should” and similar expressions are intended to identify forward-looking statements. Forward-looking statements are estimates and projections reflecting management’s reasonable judgment based on currently available information and using numerous assumptions and involve a number of risks and uncertainties that could cause actual results to differ materially from those suggested by the forward-looking statements. These risks and uncertainties include, but are not limited to, the risks detailed in our filings with the SEC, including our most recent filing on Forms 10-K and 10-Q, factors and matters contained or incorporated by reference in this document, and the following factors:

The Company believes the forward-looking statements contained herein are reasonable; however, you should not place undue reliance on forward-looking statements, which are based on current expectations and speak only as of the date of this proxy statement. Any or all of the Company’s forward-looking statements may turn out to be wrong. They can be affected by inaccurate assumptions or by known or unknown risks, uncertainties and other factors, many of which are beyond the Company’s control.

The Company is a biopharmaceutical company that discovers, develops and delivers transformative therapies for unmet medical needs. Rezurock^TM (belumosudil), an oral, once-daily tablet, is approved in the United States for the treatment of adult and pediatric patients 12 years and older with chronic graft-versus-host disease (cGVHD) after failure of at least two prior lines of systemic therapy. The Company’s clinical pipeline includes treatments for immune and fibrotic diseases as well as immuno-oncology therapies.

For more information about the Company, please visit our website at www.kadmon.com. Our website address is provided as an inactive textual reference only. The information contained on our website is not incorporated into, and does not form a part of, this proxy statement or any other report or document on file with or furnished to the SEC. For more information see “Where You Can Find More Information.”

The Company’s Common Stock is listed on The NASDAQ Global Market LLC under the symbol “KDMN.”

Sanofi is a société anonyme, a form of limited liability company, organized under the laws of France. Sanofi is a leading global healthcare company, focused on patient needs and engaged in the research, development, manufacture and marketing of therapeutic solutions. Since May 2011, they have operated under the commercial name “Sanofi” (formerly known as Sanofi-Aventis).

Sanofi’s ordinary shares are listed on Euronext Paris under the symbol “SAN” and Sanofi’s American Depository Shares are listed on The Nasdaq Global Select Market, LLC under the symbol “SNY.”

Merger Sub is a Delaware corporation and wholly owned indirect subsidiary of Sanofi. Merger Sub was formed solely for the purpose of engaging in the transactions contemplated by the Merger Agreement. As of the date of this proxy statement, Merger Sub has not engaged in any business activities other than those incidental to its formation and in connection with the transactions contemplated by the Merger Agreement. Upon completion of the Merger, Merger Sub will cease to exist and the Company will continue as the surviving corporation.

This proxy statement is being furnished to our stockholders as part of the solicitation of proxies for use at the Special Meeting to be held on [•], 2021 at [•], local time, at 450 East 29th Street, New York, NY 10016, or at any postponement or adjournment thereof. At the Special Meeting, holders of Common Stock and Preferred Stock will be asked to approve the Merger Proposal and to approve the Adjournment Proposal. In person attendance at the Special Meeting will be subject to applicable health and safety restrictions relating to COVID-19.

Our stockholders must approve the Merger Proposal in order for the Merger to occur. If our stockholders fail to approve the Merger Proposal, the Merger will not occur. A copy of the Merger Agreement is attached as Annex A to this proxy statement, which we encourage you to read carefully and in its entirety.

We are actively monitoring developments related to COVID-19. We are sensitive to the public health and travel concerns our stockholders may have and the protocols that federal, state and local governments may impose. In the event it is not possible or advisable to hold the Special Meeting in person, we will announce by issuance of a press release alternative arrangements for the meeting as promptly as practicable, which may include holding the Special Meeting solely by means of remote communication.

We have fixed the close of business on [•], 2021 as the Record Date for the Special Meeting, and only holders of record of Common Stock and Preferred Stock on the Record Date are entitled to receive notice of, and to vote at, the Special Meeting. On the Record Date, there were [•] shares of Common Stock and 28,708 shares of Preferred Stock (which, on an as-converted basis, represents voting rights equivalent to approximately [•] shares of Common Stock as of the Record Date) outstanding and entitled to vote. On all matters properly coming before the Special Meeting, you will have one vote for each share of Common Stock and approximately [•] votes per share of Preferred Stock that you owned on the Record Date.

The presence at the Special Meeting, in person or represented by proxy, of the holders of a majority in voting power of the Common Stock and Preferred Stock issued and outstanding and entitled to vote on the Record Date will constitute a quorum, permitting the conduct of business at the Special Meeting. Shares of Common Stock and Preferred Stock represented at the Special Meeting but not voted, including shares of Common Stock or Preferred Stock for which a stockholder directs an “abstention” from voting, will be counted for purposes of establishing a quorum. Broker non-votes will also be counted for purposes of establishing a quorum. A quorum is necessary to transact business at the Special Meeting. Once a share is represented at the Special Meeting, it will be counted for the purpose of determining a quorum at the Special Meeting and any adjournment of the Special Meeting. In the event that a quorum is not present at the Special Meeting, it is expected that the Special Meeting will be adjourned, postponed or delayed. If we adjourn, postpone or delay the Special Meeting for more than 30 days, or if thereafter a new Record Date is set, a notice of the adjourned, postponed or delayed meeting will be given to each stockholder of record entitled to vote at the Special Meeting in accordance with our bylaws.

Only stockholders of record, their duly authorized proxy holders, beneficial stockholders with proof of ownership and the Company’s invitees may attend the Special Meeting. To gain admittance, you must present valid photo identification, such as a driver’s license or passport. If your shares of Common Stock are held through a bank, brokerage firm or other nominee, please bring to the Special Meeting a copy of your brokerage statement evidencing your beneficial ownership of the Common Stock and valid photo identification. If you are the representative of a corporate or institutional stockholder, you must present valid photo identification along with proof that you are the representative of such stockholder. Please note that media will not be allowed to attend the Special Meeting and the taking of photographs and use of cameras, audio and video recording devices and other electronic devices will not be permitted at the Special Meeting. In person attendance at the Special Meeting will be subject to applicable health and safety restrictions relating to COVID-19, and as a result, stockholders are encouraged to vote by submitting a proxy by telephone, over the Internet or by returning the enclosed proxy card in the accompanying prepaid reply envelope.

Approval of the Merger Proposal requires the affirmative vote of the holders of a majority of the outstanding shares of Common Stock and Preferred Stock (voting on an as-converted basis with the holders of Common Stock) entitled to vote thereon. For the Merger Proposal, you may vote “FOR,” “AGAINST” or “ABSTAIN.” Abstentions, if any, will be included in the calculation of the number of shares of Common Stock and Preferred Stock represented at the Special Meeting for purposes of determining whether a quorum has been achieved, but will be counted as a vote against the Merger Proposal. If you fail to submit a proxy or to vote in person at the Special Meeting, or abstain, it will have the same effect as a vote against the Merger Proposal.

If your shares of Common Stock or Preferred Stock are registered directly in your name with our transfer agent, American Stock Transfer & Trust Company, LLC, you are considered, with respect to those shares, the “stockholder of record.” This proxy statement and proxy card have been sent directly to you by the Company.

If your shares of Common Stock are held through a bank, brokerage firm or other nominee, you are considered the “beneficial owner” of those shares held in street name. In that case, this proxy statement has been forwarded to you by your bank, brokerage firm or other nominee who is considered, with respect to those shares of Common Stock, the stockholder of record. As the beneficial owner, you have the right to direct your bank, brokerage firm or other nominee how to vote your shares by following their instructions for voting.

Under the rules of NASDAQ, banks, brokerage firms or other nominees who hold shares in street name for customers have the authority to vote on “routine” proposals when they have not received instructions from beneficial owners. However, banks, brokerage firms and other nominees are precluded from exercising their voting discretion with respect to approving non-routine matters such as the Merger Proposal and, as a result, absent specific instructions from the beneficial owner of such shares of Common Stock, banks, brokerage firms or other nominees are not empowered to vote those shares on non-routine matters. These broker non-votes will be counted for purposes of determining a quorum but will have the same effect as a vote against the Merger Proposal.

The Adjournment Proposal requires the affirmative vote of the holders of a majority of the shares of Common Stock and Preferred Stock (voting on an as-converted basis with the holders of Common Stock) present in person or represented by proxy and entitled to vote on the matter at the Special Meeting, whether or not a quorum is present. For the Adjournment Proposal, you may vote “FOR,” “AGAINST” or “ABSTAIN.” For purposes of this proposal, if your shares of Common Stock or Preferred Stock are present at the Special Meeting but are not voted on this proposal, or if you have given a proxy and abstained on this proposal, this will have the same effect as if you voted against approval of the proposal. If you fail to submit a proxy or to attend in person the Special Meeting, or there are broker non-votes on the issue, as applicable, the shares of Common Stock held by you or your broker will not be counted in respect of, and will not have an effect on, the Adjournment Proposal.

If you are a stockholder of record, you may vote your shares of Common Stock and Preferred Stock on matters presented at the Special Meeting in any of the following ways:

If you are a beneficial owner, you will receive instructions from your bank, brokerage firm or other nominee that you must follow in order to have your shares of Common Stock voted. Those instructions will identify which of the above choices are available to you in order to have your shares voted. Please note that if you are a beneficial owner and wish to vote in person at the Special Meeting, you must provide a legal proxy from your bank, brokerage firm or other nominee at the Special Meeting.

If you vote by proxy, regardless of the method you choose to vote, the individuals named on the enclosed proxy card, and each of them, with full power of substitution, will vote your shares of Common Stock and Preferred Stock in the way that you indicate. When completing the Internet or telephone processes or the proxy card, you may specify whether your shares of Common Stock and Preferred Stock should be voted for or against or to abstain from voting on all, some or none of the specific items of business to come before the Special Meeting.

If you properly sign your proxy card but do not mark the boxes showing how your shares of Common Stock and Preferred Stock should be voted on a matter, the shares of Common Stock and Preferred Stock represented by your properly signed proxy will be voted “FOR” approval of the Merger Proposal and “FOR” approval of the Adjournment Proposal.

If you have any questions or need assistance voting your shares, please contact DF King, our proxy solicitor, by calling toll-free at (800) 249-7120 or via email at KDMN@dfking.com.

IT IS IMPORTANT THAT YOU VOTE YOUR SHARES OF COMMON STOCK AND PREFERRED STOCK PROMPTLY, WHETHER OR NOT YOU PLAN TO ATTEND THE SPECIAL MEETING, AND REGARDLESS OF THE NUMBER OF SHARES OF COMMON STOCK AND/OR PREFERRED STOCK YOU OWN. PLEASE COMPLETE, DATE, SIGN AND RETURN, AS PROMPTLY AS POSSIBLE, THE ENCLOSED PROXY CARD IN THE ACCOMPANYING PREPAID REPLY ENVELOPE, OR SUBMIT YOUR PROXY BY TELEPHONE OR THE INTERNET. IF YOU ATTEND THE SPECIAL MEETING AND VOTE IN PERSON, YOUR VOTE BY BALLOT WILL REVOKE ANY PROXY PREVIOUSLY SUBMITTED.

As of [•], 2021, the Record Date, the directors and executive officers of the Company beneficially owned and were entitled to vote, in the aggregate, [•] shares of Common Stock, representing [•] percent of the outstanding shares of Common Stock and Preferred Stock (on an as-converted to Common Stock basis).

Any stockholder of record entitled to vote at the Special Meeting may submit a proxy by telephone, over the Internet, by returning the enclosed proxy card in the accompanying prepaid reply envelope, or may vote in person by appearing at the Special Meeting. If your shares of Common Stock are held in “street name” through a bank, brokerage firm or other nominee, you should instruct your bank, brokerage firm or other nominee on how to vote your shares using the instructions provided by your bank, brokerage firm or other nominee. If you fail to submit a proxy or to vote in person at the Special Meeting, or do not provide your bank, brokerage firm or other nominee with instructions, as applicable, your shares of Common Stock and Preferred Stock will not be voted on the Merger Proposal which will have the same effect as a vote against the proposal, and your shares will not have an effect on the Adjournment Proposal.

You have the right to revoke a proxy, whether delivered over the Internet, by telephone or by mail, at any time before it is exercised, by voting again at a later date through any of the methods available to you, by giving written notice of revocation to our Secretary or by attending the Special Meeting and voting in person. Written notice of revocation should be mailed to: Kadmon Holdings, Inc., Attention: Corporate Secretary, 450 East 29th Street, New York, NY.

Although it is not currently expected, if the Adjournment Proposal is approved, the Special Meeting may be adjourned for the purpose of, if necessary and for a minimum period of time reasonable under the circumstances, ensuring that any necessary supplement or amendment to this proxy statement is provided to Company stockholders a reasonable amount of time in advance of the Special Meeting, or for the purpose of soliciting additional proxies if there are insufficient votes at the time of the Special Meeting to approve the Merger Proposal or if a quorum is not present at the Special Meeting. Any adjournment of the Special Meeting will allow the Company’s stockholders who have already sent in their proxies to revoke them at any time prior to their use at the Special Meeting, as adjourned. If we adjourn the Special Meeting for more than 30 days, or if after adjournment a new Record Date is set, a notice of the adjourned meeting will be given to each stockholder of record entitled to vote at the Special Meeting in accordance with our bylaws.

We are working toward completing the Merger as soon as possible. Assuming receipt of required regulatory approvals and timely satisfaction of other closing conditions, including the approval by our stockholders of the Merger Proposal, we expect the Merger to be completed in the fourth quarter of 2021. If our stockholders vote to approve the Merger Proposal, the Merger will become effective as promptly as practicable following the satisfaction or waiver of the other conditions to the Merger, subject to the terms of the Merger Agreement. For more information see “The Merger—Closing and the Effective Time.”

Stockholders are entitled to appraisal rights under the DGCL in connection with the Merger. This means that you are entitled to have the fair value of your shares of Common Stock or Preferred Stock determined by the Delaware Court of Chancery and to receive payment based on that valuation in lieu of the Merger Consideration if you follow exactly the procedures specified under the DGCL. The ultimate amount you receive in an appraisal proceeding may be less than, equal to or more than the amount you would have received under the Merger Agreement.

To exercise your appraisal rights, you must submit a written demand for appraisal to the Company before the vote is taken on the Merger Agreement and you must not vote (either in person or by proxy) in favor of the Merger Proposal. Your failure to follow exactly the procedures specified under the DGCL may result in the loss of your appraisal rights. See “Appraisal Rights” beginning on page [79] and the text of the Delaware appraisal rights statute reproduced in its entirety as Annex B to this proxy statement. If you hold your shares of Common Stock through a bank, brokerage firm or other nominee and you wish to exercise appraisal rights, you should consult with your bank, brokerage firm or other nominee to determine the appropriate procedures for the making of a demand for appraisal by your bank, brokerage firm or other nominee. In view of the complexity of the DGCL, stockholders who may wish to pursue appraisal rights should consult their legal and financial advisors promptly.

The Company has engaged DF King to assist in the solicitation of proxies for the Special Meeting. The Company estimates that it will pay DF King a fee of $25,000. The Company has also agreed to reimburse DF King for, pay directly, or, where requested in special situations, advance sufficient funds for the payment of, certain fees, costs and expenses and will also indemnify DF King, its affiliates and their respective officers, directors, employees, agents and other representatives and controlling persons against certain losses, claims, damages, liabilities and expenses. The Company is soliciting proxies for the Special Meeting and will bear the costs and expenses of such solicitation. The Company may also reimburse banks, brokers or their agents for certain expenses in forwarding proxy materials to beneficial owners of Common Stock. Our directors, officers and employees may also solicit proxies by telephone, by facsimile, by mail, on the Internet or in person. They will not be paid any additional amounts for soliciting proxies.

If you have more questions about the Merger or how to submit your proxy, or if you need additional copies of this proxy statement or the enclosed proxy card or voting instructions, please contact DF King, our proxy solicitor, by calling toll-free at (800) 249-7120 or via email at KDMN@dfking.com.

The descriptions of the Merger in this section and elsewhere in this proxy statement are qualified in their entirety by reference to the complete text of the Merger Agreement, a copy of which is attached as Annex A and is incorporated by reference into this proxy statement. You should read the entire Merger Agreement carefully as it is the legal document that governs the Merger.

Upon the terms and subject to the conditions of the Merger Agreement, at the Effective Time, Merger Sub will merge with and into the Company. The Company will be the Surviving Corporation in the Merger, will become a wholly owned indirect subsidiary of Sanofi and will continue to exist following the Merger. As a result of the Merger, the Company will cease to be a publicly traded company, the Common Stock will be delisted from NASDAQ and deregistered under the Exchange Act, and the Company will no longer file periodic reports with the SEC. If the Merger is completed, you will not own any shares of the capital stock of Sanofi or the Surviving Corporation.

The Effective Time will occur upon the filing of the certificate of merger with the Secretary of State of the State of Delaware as provided under the DGCL (or at such later time as we and Sanofi may agree and specify in the certificate of merger).

In the Merger, each outstanding share of Common Stock outstanding immediately prior to the Effective Time (other than Excluded Shares) will be canceled and cease to exist and converted into the right to receive the Common Stock Merger Consideration, without interest thereon, less any applicable withholding taxes. At the Effective Time of the Merger, each share of Preferred Stock issued and outstanding as of immediately prior to the Effective Time (other than Dissenting Shares) will be canceled and cease to exist and automatically convert into the right to receive the Preferred Stock Merger Consideration, without interest thereon, less any applicable withholding taxes. After the Merger is completed, you will have the right to receive the Merger Consideration, but you will no longer have any rights as a stockholder (except that stockholders who properly exercise their appraisal rights will have the right to receive a payment for the “fair value” of their shares as determined pursuant to an appraisal proceeding as contemplated by the DGCL, as described below under the caption “Appraisal Rights”).

The following chronology summarizes the key meetings and events that led to the signing of the Merger Agreement. The following chronology does not purport to catalogue every conversation among the Board of Directors, members of Company management or the representatives of the Company and other parties.

The Board of Directors, with the Company’s senior management, regularly reviews the Company’s business, operations, financial performance and strategic direction for the purpose of increasing stockholder value. As part of this on-going review, the Board of Directors considers the Company’s long-term strategies and plans, changes in the industry and markets in which the Company operates, execution opportunities and risks, potential strategic transaction opportunities, including partnership and collaboration opportunities and financial alternatives in light of developments of the Company’s clinical and commercial stage products. As part of this process, Company management regularly engages in business development and strategic discussions with various participants in the biopharmaceutical industry.

On February 16, 2021, the Company issued 3.625% convertible senior notes due 2027 (the “Convertible Notes”) in the aggregate principal amount of $240 million, the proceeds of which the Company anticipated would enable it to advance its planned commercial launch efforts for belumosudil and advance certain of its other pipeline product candidates, including KD033, part of the Company’s immuno-oncology platform.

On June 26, 2021, Matthieu Merlin, Head of Business Development and Licensing (General Medicines Business Unit) of Sanofi, reached out to a representative of the Company to set up an introductory meeting to explore potential opportunities for collaboration between the two companies. At the time of Sanofi’s outreach, the U.S. Food and Drug Administration (the “FDA”) was reviewing the New Drug Application for belumosudil, the Company’s lead product candidate, with a Prescription Drug User Fee Act target action date of August 30, 2021. Other of the Company’s product candidates remain in different stages of clinical and preclinical development.

The Company has from time to time utilized the services of Moelis and Cantor Fitzgerald for investment banking and other financial services unrelated to the Merger, including Cantor Fitzgerald acting as sole bookrunner

in connection with the Company’s issuance of the Convertible Notes in February 2021, acting as the placement agent for the Company’s ongoing at-the-market offering program, executing two block trades on behalf of the Company in October 2019 and May 2020 and acting as the joint bookrunner for the Company’s public offering of Common Stock in November 2019.

On June 16, 2021, a representative from a potential strategic bidder for the Company (“Party A”) sent an email to representatives of Moelis, requesting an introduction to the Company. On June 29, 2021, a representative of Moelis introduced the representative of Party A to Steven Meehan, Executive Vice President and Chief Financial Officer of the Company.

On July 8, 2021, representatives of Party A held a conference call with representatives of the Company, including Harlan W. Waksal, M.D., President and Chief Executive Officer of the Company and Mr. Meehan, during which the parties discussed a general corporate overview of each company and potential synergies that may arise from a collaboration or other strategic transaction.

On July 12, 2021, Mr. Merlin held a video conference with Gregory S. Moss, Executive Vice President, General Counsel and Corporate Secretary, Chief Compliance Officer of the Company, during which Mr. Merlin and Mr. Moss each introduced their company to the other, and Mr. Merlin discussed Sanofi’s interest in belumosudil. Mr. Moss discussed the Company’s overall development plan with respect to belumosudil, including its focus on the United States and pursuing various global approvals via the FDA’s Project Orbis framework. Mr. Moss also discussed the Company’s innovative pipeline and various corporate aspects of its business.

On July 16, 2021, the FDA approved belumosudil for the treatment of adult and pediatric patients 12 years and older with chronic graft-versus-host disease after failure of at least two prior lines of systemic therapy. The FDA reviewed the New Drug Application six weeks ahead of the Prescription Drug User Fee Act goal date of August 30, 2021. As a result of the announcement, the per share price of the Company’s common stock closed at $4.28 on July 16, 2021, up from $3.55 from the prior trading day’s closing price.

On July 20, 2021, Mr. Merlin held a videoconference with Mr. Moss and other representatives of the Company, during which Mr. Merlin affirmed Sanofi’s interest in belumosudil but also indicated that Sanofi may be interested in exploring a larger transaction taking into account the Company’s product candidates still in development in addition to the commercialization of belumosudil. Mr. Merlin also noted that Sanofi was interested in learning more about the Company’s immuno-oncology platform and other pipeline assets and programs. On July 20, 2021, the Company entered into a confidentiality agreement with Sanofi which did not contain standstill provisions.

Mr. Merlin and Mr. Moss held a videoconference on July 21, 2021, where Mr. Merlin asked about the Company’s work-to-date around potentially separating out the Company’s immuno-oncology platform. Mr. Moss responded that a detailed analysis had not been conducted but informal options had been contemplated and considered. Mr. Merlin indicated that Sanofi’s interest was firm and expeditious, and Mr. Merlin and Mr. Moss agreed that an in-person management presentation was an appropriate next step, as well as contemporaneous subject matter expert discussion.

On July 26, 2021, Kadmon and Party A entered into a confidentiality agreement with standstill provisions (which permitted private waivers of the standstill provision and contained a customary “fallaway” provision in the event the Company announced a change of control transaction).

On July 27, 2021, representatives of the Company, including Dr. Waksal, Mr. Moss, and Dr. Jeegar Patel, Senior Vice President, Research and Non-Clinical Development, held a meeting with representatives from Sanofi (including Mr. Jean-Baptiste de Chatillon, Chief Financial Officer of Sanofi, Mr. Olivier Charmeil, Executive Vice President – General Medicines of Sanofi, Mr. Loic Gonnet, Global Head of Mergers & Acquisitions of Sanofi, and Mr. Merlin), with Mr. Meehan and other representatives of Sanofi participating by videoconference. During this meeting the parties discussed information regarding belumosudil, the Company’s immuno-oncology platform and other information regarding the Company and its additional pipeline candidates. At a dinner following the meeting, Mr. de Chatillon, Mr. Charmeil and Mr. Gonnet confirmed that Sanofi was interested in acquiring the Company.

On July 28, 2021, representatives of the Company, including Dr. Waksal, Mr. Moss and Dr. Patel met with representatives of Party A in their European headquarters with Mr. Meehan and certain representatives of Party A participating by videoconference. During this meeting the parties discussed belumosudil, the Company’s product pipeline and other information. Also, during this meeting, Party A indicated that it was interested in acquiring the Company.

A potential strategic bidder for the Company (“Party B”) had previously indicated an interest in exploring potential business development opportunities with the Company following approval of belumosudil. Accordingly, as the Company began to have discussions with Sanofi and Party A, the Company and representatives of the Company Financial Advisors discussed reaching out to Party B. On July 29, 2021, Mr. Meehan had a telephone call with a representative of Party B to let them know the Company may be considering a potential collaboration or other strategic transactions and to gauge their interest in exploring such a potential transaction.

On July 30, 2021, Dr. Waksal, Mr. Meehan and Mr. Moss held an informal discussion with Mr. Tasos Konidaris, Chairman of the Board of Directors, and directors Mr. Arthur Kirsch and Ms. Nancy Miller-Rich, during which management provided an update of the discussions with Sanofi, Party A and Party B.

On July 30, 2021, the Company received an e-mail from a representative of Party B introducing representatives of the Company, including Mr. Meehan and Mr. Moss, to other representatives of Party B for purposes of discussing a potential transaction.

On August 1, 2021, the Company and Sanofi amended their confidentiality agreement to provide for standstill provisions (which permitted private waivers of the standstill provisions and contained a customary “fallaway” provision in the event the Company announced a change of control transaction).

On August 3, 2021, the Board of Directors held a regular meeting attended by Mr. Meehan, Mr. Moss, representatives of each of the Company Financial Advisors and a representative of DLA Piper LLP (US) (“DLA Piper”), outside counsel to the Company. Management discussed with the Board of Directors the interest in the Company by Sanofi, Party A and Party B and the related discussions to date. The representative of DLA Piper then reviewed with the Board of Directors their fiduciary duties and related considerations. After discussion and deliberation, including with respect to potential benefits to the Company’s stockholders of a potential sale of the Company and the risk and uncertainties if the Company were to remain an independent public company, the Board of Directors determined it to be in the best interest of the Company and its stockholders to take further steps to confidentially explore the potential interest of third parties to acquire the Company, including the interest of Sanofi, Party A and Party B. The Board of Directors also designated Mr. Konidaris, Mr. Kirsch and Ms. Miller-Rich, each of whom is an independent, disinterested director, and Dr. Waksal, as members of a transaction committee of the Board of Directors (the “Transaction Committee”) and instructed the Transaction Committee to engage Cantor Fitzgerald and Moelis, and to oversee the activities of management and Cantor Fitzgerald and Moelis in connection with exploring a potential sale of the Company and to provide follow-up communication to the Board of Directors, as appropriate. However, the Board of Directors determined that final authority with respect to any transaction would reside with the full Board of Directors. The Transaction Committee was set up for efficiency purposes, and not due to any perceived conflict of interest with respect to any member of the Board of Directors.

On August 4, 2021, each of Sanofi and Party A were notified that the Board of Directors had engaged the Company Financial Advisors and authorized the exploration of a potential sale of the Company. In addition, Party A was provided access to a virtual data room. Also on August 4, 2021, the Company received a non-binding indication of interest from Sanofi to acquire all of the Common Stock for $7.00 per share, a 55% premium to the closing price per share on August 3, 2021, and with a request to enter into an exclusivity agreement. After receipt of the non-binding indication of interest, the Transaction Committee held a virtual meeting attended by Mr. Meehan, Mr. Moss, Kyle Carver, the Company’s Chief Accounting Officer, representatives of the Company Financial Advisors and representatives of DLA Piper to review the Sanofi non-binding indication of interest and, after discussion, determined that it undervalued the Company. After discussion, the Transaction Committee directed management of the Company to inform Sanofi that the proposal undervalued the Company and the Company was not interested in a transaction at that level. Following the meeting, management delivered the Board of Director’s message to Sanofi.

Between August 4, 2021 and August 23, 2021, Party A conducted due diligence.

On August 5, 6 and 7, 2021, the Company Financial Advisors held calls with representatives of Centerview Partners, financial advisor to Sanofi (“Centerview”) to discuss the Company’s rationale for rejecting Sanofi’s August 4, 2021 proposal.

On August 5, 2021, the Company and Party B entered into a confidentiality agreement that contained standstill provisions (which permitted private waivers of the standstill provision, private offers to the Board of Directors and contained a customary “fallaway” provision in the event the Company announced a change of control transaction).

On August 6, 2021, Party B was provided access to the virtual data room. Also on August 6, 2021, representatives of the Company, including Dr. Waksal, Mr. Meehan, Mr. Moss and Mr. Patel held a telephone conference with Party A, in which the parties discussed research and development related to the Company’s products other than belumosudil.

On August 9, 2021, the Company received a revised non-binding indication of interest from Sanofi to acquire all of the Common Stock for $9.00 per share, an 81% premium to the closing price per share on August 6, 2021, and with a request to enter into an exclusivity agreement.

On August 10, the Transaction Committee, together with Mr. Meehan and Mr. Moss, met to discuss interactions to date with Sanofi, Party A and Party B and to review Sanofi’s August 9, 2021 revised non-binding indication of interest. The Transaction Committee instructed the management team to explore potential transaction opportunities with parties other than Sanofi, Party A and Party B. The Transaction Committee also instructed the Company’s management team to convey to Sanofi that the Company would not agree to exclusivity at an offer price of $9.00 per share, but that it would allow Sanofi to begin conducting its due diligence. In addition, after discussions with management and representatives of the Company Financial Advisors, the Transaction Committee directed representatives of the Company Financial Advisors to reach out to six other strategic companies to gauge their interest in a potential transaction with the Company.

Between August 10 and August 11, at the direction of Dr. Waksal, Mr. Meehan and Mr. Moss, representatives of the Company Financial Advisors contacted six other strategic companies in connection with exploring a business combination transaction with the Company, but none of the six parties expressed meaningful interest in such a transaction.

On August 11, 2021, at the direction of the Transaction Committee, representatives of the Company Financial Advisors discussed Sanofi’s August 9, 2021 proposal with representatives of Centerview and conveyed that, although Sanofi’s August 9, 2021 proposal was below the Company’s expectations and exclusivity would not be granted, Sanofi and its representatives would be provided with access to a virtual data room in order to conduct due diligence.

On August 11, 2021, Dr. Waksal, Mr. Meehan, Mr. Moss and Mr. Patel participated in a management presentation with representatives of Party B by videoconference.

On August 12, 2021, Sanofi was provided access to a virtual data room. From August 12, 2021 through September 7, 2021, Sanofi engaged in due diligence.

On August 13, 2021, the Company entered into an engagement letter with each of Cantor Fitzgerald and Moelis to retain Cantor Fitzgerald and Moelis, respectively, as financial advisor to assist the Company in connection with a potential sale of the Company.

On August 13, 2021, Mr. Carver and a representative of the Company’s third party tax advisor participated in a tax and financial due diligence call with Party A. Also on August 13, 2021, Mr. Moss participated in a due diligence call with Party B and its counsel regarding the Company’s intellectual property.

On August 17, 2021, Mr. Moss, Mr. Meehan and representatives of DLA Piper held a due diligence call with representatives of Sanofi regarding the Company’s intellectual property and other legal due diligence matters.

On August 18, 2021, Dr. Waksal, Mr. Meehan, Mr. Moss and Mr. Carver held a due diligence call with representatives of Party B regarding the Company’s commercial strategy. Also on August 18, 2021, Party A informed the Company that it was no longer interested in acquiring the Company due to the anticipated time frame for obtaining marketing authorization for belumosudil in Europe.

On August 19, 2021, representatives of the Company participated in numerous due diligence calls with Sanofi regarding various matters, including product lifecycle management, clinical studies and finance.

On August 21, 2021, the Company received a revised non-binding indication of interest from Sanofi to acquire all of the Common Stock for $9.50 per share, an 88% premium to the closing price per share on August 20, 2021, and with a request to enter into an exclusivity agreement.

On August 22, 2021 and August 24, 2021, the compensation committee of the Board of Directors (the “Compensation Committee”) held special meetings, with representatives of DLA Piper present, to discuss and

evaluate potential adjustments to the compensation arrangements and retention bonuses for Dr. Waksal, Mr. Meehan and Mr. Moss. To aid in such discussion, the Compensation Committee reviewed and discussed compensation data for comparable companies provided by the Company’s executive compensation consultants, Veritas.

At the direction of senior management of the Company, on August 22, 2021, representatives of the Company Financial Advisors held a call with the representatives of Centerview, during which Centerview confirmed that the August 21, 2021 Sanofi offer was a “final offer.”

On August 23, 2021, the Board of Directors held a special meeting attended by Mr. Meehan, Mr. Moss, Mr. Carver, representatives of DLA Piper and representatives of the Company Financial Advisors to review the revised Sanofi proposal. Management and representatives of the Company Financial Advisors provided an update to the Board of Directors on the process conducted to date, including that Party B was significantly behind in conducting due diligence and that it was not in a position to provide an indication of value. Based in part on the status of discussions with Party B, the Board of Directors authorized the Company to enter into an exclusivity agreement with Sanofi based on a price per share of at least $9.50. After the meeting of the Board of Directors, Mr. Waksal delivered a letter to Sanofi confirming that the Company would enter into an exclusivity agreement, subject to mutually agreeable terms.

On August 23, 2021, the Transaction Committee held a virtual special meeting attended by Mr. Meehan, Mr. Moss, Mr. Carver, and representatives of DLA Piper to review the proposed draft merger agreement (which draft agreement had been provided to the Transaction Committee in advance of the meeting), which included a Company termination fee equal to approximately 2.5% of the Company’s equity value payable upon termination under certain circumstances. After discussion, the Transaction Committee directed DLA Piper to distribute the draft merger agreement to Weil, Gotshal & Manges LLP, counsel to Sanofi (“Weil”). Following the meeting DLA Piper distributed the draft merger agreement and a draft exclusivity agreement to Weil.

On August 24, 2021, the Company and Sanofi entered into a 10-day exclusivity agreement that would be extended automatically thereafter until the date either party informed the other it was no longer interested in pursuing a transaction. Also on August 24, 2021, August 26, 2021, and August 30, 2021, representatives of the Company and DLA Piper conducted due diligence meetings with representatives of Sanofi and Weil regarding the Company’s intellectual property and upstream licenses.

On August 25 and 27, 2021, the Compensation Committee held a special meeting with representatives of DLA Piper present, to discuss the Company’s executive compensation.

On August 31, 2021, Weil distributed a mark-up to the merger agreement, which mark-up included (i) a requirement that the Company’s largest stockholder enter into a voting support agreement with respect to the transaction (the “Support Agreement Requirement”), (ii) a Company termination fee equal to approximately 4% of the Company’s equity value and (iii) that the Company make certain representations regarding compliance with the diligence requirements of the upstream licenses relating to belumosudil and that Sanofi receive, prior to execution of the Merger Agreement, certain written assurances from the stockholder representative of the parties to the upstream licenses (the “Stockholder Representative”) regarding the reversion rights relating to the upstream licenses for belumosudil (which we refer to as the “Upstream Licenses Assurances”).

From September 1, 2021 through September 3, 2021, representatives of the Company, DLA Piper, Sanofi, Weil, the Company Financial Advisors and/or Centerview held several discussions regarding the Upstream Licenses Assurances. In these meetings and calls, representatives of Sanofi and Weil informed the representatives of the Company that Sanofi would not proceed with exploring a transaction without the Upstream License Assurances.

On September 1, 2021, DLA Piper distributed a revised draft of the merger agreement, which did not include any Support Agreement Requirement or obligation to obtain any pre-execution Upstream Licenses Assurances and provided for a Company termination fee equal to approximately 3% of the Company’s equity value.

On September 2, 2021, representatives of the Company, including Dr. Waksal, Mr. Moss and Mr. Meehan, representatives of Sanofi, representatives of DLA Piper and Weil, and representatives of Moelis, Cantor Fitzgerald and Centerview held a virtual due diligence meeting with the Stockholder Representative, during which Sanofi requested an acknowledgement from the Stockholder Representative that the Company had complied with its obligations under the upstream licenses. Following the meeting, the Company distributed a draft acknowledgement to the Stockholder Representative.

On September 2, 2021, the Transaction Committee held a virtual special meeting attended by Mr. Meehan, Mr. Moss, Mr. Carver and representatives of DLA Piper, during which meeting the management and representatives of DLA Piper updated the Transaction Committee on the status of negotiations with Sanofi. In addition, representatives of DLA Piper reviewed with the Board of Directors remaining open issues on the draft Merger Agreement (the latest draft of which was distributed to the Transaction Committee in advance of the meeting), which included, in addition to the Upstream License Assurances and related Company representations, (i) the size of the termination fee the Company would have to pay in order to terminate the Merger Agreement to accept a Superior Proposal or for the Board of Directors to change its recommendation and (ii) the Support Agreement Requirement.

On September 3, 2021, Weil distributed a revised draft of the Merger Agreement without the Support Agreement Requirement. Also, on September 3, 2021, the Company distributed a draft of the Company’s disclosure letter.

From September 4, 2021 through September 7, 2021, representatives of DLA Piper and Weil continued to negotiate the terms and exchange drafts of the Merger Agreement and the Company’s disclosure letter.

On September 6, 2021, the Board of Directors held a special meeting attended by all the directors, and Mr. Meehan, Mr. Moss and Mr. Carver and representatives of Cantor Fitzgerald, Moelis and DLA Piper. A representative of DLA Piper reviewed with the Board of Directors the status of negotiations with Sanofi and the terms of the proposed Merger Agreement and related transaction documents. A representative of Moelis then reviewed with the Board of Directors, based upon materials provided to the Board of Directors in advance of the meeting, Moelis’s financial analysis of the Merger Consideration to be received by the holders of Common Stock of the Company in the Merger. A representative of Cantor Fitzgerald then reviewed with the Board of Directors, based upon materials provided to the Board of Directors in advance of the meeting, Cantor Fitzgerald’s financial analysis of the Merger Consideration to be received by the holders of Common Stock of the Company in the Merger. The Board of Directors discussed the analysis of each of the Company Financial Advisors and asked questions of the Company Financial Advisors regarding such analyses. The Board of Directors then further discussed and considered the proposed transaction, including the potential benefits of, and risks related to, the transaction and the Company’s standalone prospects as described in more detail below under “Reasons for the Merger,” and the remaining issue under negotiation, the scope of the representations of the Company regarding the upstream licenses. The Board of Directors then met in executive session, without management present, and discussed and approved, subject to the Board of Directors’ approval of the Merger, (a) changes to the Employment Agreements and compensation arrangements of Dr. Waksal, Mr. Meehan and Mr. Moss, and (b) transaction bonuses payable to certain other employees, contingent upon consummation of the Merger and continued employment through such time. The Board of Directors instructed the Company’s management and DLA Piper to engage with Sanofi and its counsel to finalize the remaining issues in the Merger Agreement and reconvene the Board of Directors the following day. Also on September 6, the Company received a letter from the Stockholder Representative acknowledging, among other things, that the Company had complied with its obligations under the upstream licenses relating to belumosudil, a copy of which was provided to Sanofi.

On the afternoon of September 7, 2021, the Board of Directors held a special meeting attended by all the directors, Mr. Meehan, Mr. Moss, and Mr. Carver and representatives of Cantor Fitzgerald, Moelis and DLA Piper. Mr. Moss and a representative of DLA Piper updated and reviewed with the Board of Directors the final revisions to the proposed Merger Agreement (the draft of which was provided to the Board of Directors in advance of the meeting). Each of Moelis and Cantor Fitzgerald was asked to confirm that there were no changes to the analysis presented to the Board of Directors the previous day. After further discussion, representatives of Moelis rendered an oral opinion, subsequently confirmed in writing on September 7, 2021, to the Board of Directors that, as of such date and based upon and subject to the various assumptions made, procedures followed, matters considered, and qualifications and limitations set forth therein, the Common Stock Merger Consideration of $9.50 per share to be received in the Merger by holders of Common Stock, other than Sanofi and its affiliates and holders of Excluded Shares, pursuant to the Merger Agreement was fair, from a financial point of view, to such holders. The full text of the written opinion of Moelis, dated September 7, 2021, is attached as Annex D to this proxy statement and is described in more detail below under “Opinions of the Company Financial Advisors—Opinion of Moelis & Company LLC.” Representatives of Cantor Fitzgerald then rendered an oral opinion, subsequently confirmed in writing on September 7, 2021, to the Board of Directors to the effect that, as of September 7, 2021 and based on and subject to the assumptions, matters considered and limitations, conditions and qualifications described in its opinion, the Common Stock Merger Consideration of $9.50 per share to be received in the Merger by the holders of Common Stock (other than Sanofi and its affiliates) was fair, from a financial point of view, to such holders. The full text of

the written opinion of Cantor Fitzgerald, dated September 7, 2021, is attached as Annex C to this proxy statement and is described in more detail below under “Opinions of the Company Financial Advisors—Opinion of Cantor Fitzgerald.” The Board of Directors then further discussed and considered the proposed transaction, including the potential benefits of, and risks related to, the transaction and the Company’s standalone prospects as described in more detail below under “Reasons for the Merger.” Following such discussion and consideration, the Board of Directors determined to proceed with the transaction and unanimously adopted and approved the Merger and the entry into the Merger Agreement, determined that the Merger Agreement, the Merger and the other transactions contemplated by the Merger Agreement are substantively and procedurally fair to and in the best interests of the Company and its stockholders, and resolved to recommend that the stockholders of the Company adopt the Merger Agreement and approve the Merger.

On the afternoon of September 7, 2021, the Company and Sanofi executed the Merger Agreement and on the morning of September 8, 2021, issued a press release announcing their entry into the Merger Agreement.

The Board of Directors has (i) determined that the Merger Agreement and the transactions contemplated thereby, including the Merger, are fair to and in the best interests of the Company and its stockholders, (ii) approved and declared advisable the Merger Agreement and the transactions contemplated thereby, including the Merger, (iii) resolved to recommend that the Company’s stockholders adopt the Merger Agreement and approve the Merger, and (iv) directed that the Merger Agreement be submitted to the Company’s stockholders for their adoption. The Board of Directors made its determination after consultation with its legal and financial advisors and consideration of a number of factors. For some of the factors considered, see “The Merger—Reasons for Recommendation.”

In considering the recommendation of the Board of Directors with respect to the Merger Proposal, you should be aware that our directors and executive officers have interests in the Merger that may be different from, or in addition to, yours. The Board of Directors was aware of and considered these interests, among other matters, in evaluating the Merger and in recommending that the Merger Agreement be adopted by the stockholders of the Company. See under the heading “The Merger—Interests of Directors and Executive Officers in the Merger.”

The Board of Directors recommends that you vote “FOR” approval of the Merger Proposal and “FOR” approval of the Adjournment Proposal.

In evaluating the Merger Agreement, the Merger and the other transactions contemplated by the Merger Agreement, the Board of Directors consulted with the Company’s senior management, as well as representatives of its financial advisors and outside legal counsel. In the course of making its determination (1) that the Merger Agreement and the transactions contemplated by the Merger Agreement, including the Merger, are fair to, and in the best interests of, the Company and its stockholders and (2) to recommend that the Board of Directors approve and declare advisable the Merger Agreement and the transactions contemplated by the Merger Agreement, including the Merger, the Board of Directors considered numerous factors, including the following non-exhaustive list of material factors and benefits of the Merger, each of which the Board of Directors believed supported its determination and recommendation:

Common Stock Merger Consideration. The Board of Directors considered:

Business and Financial Condition. The Board of Directors considered the Company’s historical and projected business, industry, markets, financial performance and condition and its prospects.

Risks and Uncertainties. The Board of Directors considered, among other factors, that the Company’s business and that its stockholders would continue to be subject to significant risks and uncertainties if the Company remained an independent public company, including:

The Sale Process. The Board of Directors considered:

Negotiation Process. The Board of Directors considered the fact that the terms of the Merger Agreement were the result of robust arm’s-length negotiations conducted by the Company, with the knowledge and at the direction of the Board of Directors, and with the assistance of independent financial advisors and outside legal counsel.

Cantor Fitzgerald’s Financial Analysis. The Board of Directors considered the financial analysis of the Common Stock Merger Consideration that Cantor Fitzgerald reviewed with the Board of Directors on September 6, 2021, including Cantor Fitzgerald’s opinion rendered to the Board of Directors on September 7, 2021, to the effect that, as of such date and based upon and subject to various assumptions, matters considered and limitations, conditions and qualifications described in its opinion, the Common Stock Merger Consideration to be received in the Merger by holders of the outstanding shares of Common Stock (other than Sanofi and its affiliates) was fair from a financial point of view to such holders. For a description of Cantor Fitzgerald's opinion, please see below under “—Opinions of the Company Financial Advisors—Opinion of Cantor Fitzgerald.” The written opinion delivered by Cantor Fitzgerald is attached hereto as Annex C.

Moelis’s Financial Analysis. The Board of Directors considered the financial analysis of the Common Stock Merger Consideration that Moelis reviewed with the Board of Directors on September 6, 2021, including Moelis’ opinion rendered to the Board of Directors on September 7, 2021, to the effect that, as of such date and based upon and subject to the various assumptions made, procedures followed, matters considered, and qualifications and limitations set forth therein, the Common Stock Merger Consideration of $9.50 per share to be received in the Merger by holders of Common Stock, other than Sanofi and its affiliates and holders of Excluded Shares, pursuant to the Merger Agreement was fair, from a financial point of view, to such holders. For a description of the Moelis’ opinion, please see below under “—Opinions of the Company Financial Advisors—Opinion of Moelis & Company LLC”. The written opinion delivered by Moelis is attached hereto as Annex D.

Certainty of Consideration. The Board of Directors considered that the all-cash nature of the consideration to be paid in the Merger allows Company stockholders to realize immediate and certain premium cash value and liquidity, while avoiding the significant future risks and uncertainties for the Company and the markets generally.

Company Projections. The Board of Directors considered Company Projections, which reflect an application of various assumptions of the Company’s senior management. The Board of Directors considered the inherent uncertainty of attaining management’s forecasts, including those set forth in “—Company Projections,” and that due to such uncertainty the Company’s actual financial results in future periods could differ materially from management’s forecasted results.

Likelihood of Completion; Certainty of Payment. The Board of Directors considered its belief that, absent a superior proposal, the Merger represented a transaction that would likely be consummated based on, among other factors:

Other Terms of the Merger Agreement. The Board of Directors considered other terms of the Merger Agreement, which are more fully described below under the heading “The Merger Agreement.” Certain provisions of the Merger Agreement that the Board of Directors considered significant include:

The Board of Directors also considered a number of uncertainties, risks and potentially negative factors in its deliberations concerning the Merger and the other transactions contemplated by the Merger Agreement, including the following:

The foregoing discussion is not meant to be exhaustive, but summarizes material factors considered by the Board of Directors in its consideration of the Merger. After considering these and other factors, the Board of Directors concluded that the potential benefits of the Merger outweighed the uncertainties and risks. In view of the variety of factors considered by the Board of Directors and the complexity of these factors, the Board of Directors did not find it practicable to, and did not, quantify or otherwise assign relative weights to the foregoing factors in reaching its determination and recommendations. Moreover, each member of the Board of Directors applied his or her own personal business judgment to the process and may have assigned different weights to different factors. Upon due consideration of these and other factors, the Board of Directors believed that, overall, the potential benefits of the Merger to the Company’s stockholders outweighed the risks and uncertainties of the Merger and adopted and approved the Merger Agreement, the Merger and the other transactions contemplated by the Merger Agreement and recommends that stockholders adopt the Merger Agreement and approve the Merger based upon the totality of the information presented to and considered by the Board of Directors.

The Company retained Cantor Fitzgerald to act as its financial advisor in connection with the Merger. In connection with the Merger, Cantor Fitzgerald rendered its opinion to the Board of Directors on September 7, 2021, to the effect that, as of that date and based on and subject to various assumptions, matters considered and limitations, conditions and qualifications described in its opinion, the Common Stock Merger Consideration to be received in the Merger by holders of the outstanding shares of Common Stock (other than Sanofi and its affiliates) was fair, from a financial point of view, to such holders.

The full text of Cantor Fitzgerald’s opinion describes the assumptions made, procedures followed, matters considered and limitations on the review undertaken by Cantor Fitzgerald. This opinion is attached as Annex C and is incorporated herein by reference. Cantor Fitzgerald’s opinion was provided for the benefit and use of the Board of Directors (in its capacity as such) in connection with its consideration of the Merger. Cantor Fitzgerald’s opinion did not constitute a recommendation to the Board of Directors in connection with the Merger, nor did the opinion constitute a recommendation to any holders of Common Stock should vote or act with respect to the Merger or any related matter. Cantor Fitzgerald’s opinion did not address the Company’s underlying business decision to pursue the Merger, the relative merits of the Merger as compared to any alternative business or financial strategies that might exist for the Company or the effects of any other transaction in which the Company might engage. The following summary is qualified in its entirety by reference to the full text of Cantor Fitzgerald’s opinion.

In the course of performing its reviews and analyses for rendering its opinion, Cantor Fitzgerald:

Cantor Fitzgerald relied upon and assumed, without independent verification, the accuracy and completeness of the financial and other information provided to or discussed with Cantor Fitzgerald by the Company or obtained by Cantor Fitzgerald from public sources, including, without limitation, the projections referred to above. With respect to the projections, Cantor Fitzgerald relied on representations that they have been reasonably prepared on bases reflecting the best currently available estimates and judgments of the Company’s senior management as to the expected future performance of the Company. Cantor Fitzgerald did not assume any responsibility for the independent verification of, and did not independently verify, any such information, including, without limitation, the projections; Cantor Fitzgerald expressed no view or opinion as to such projections or the assumptions upon which they were based; and Cantor Fitzgerald further relied upon the assurances of the Company’s senior management that it was unaware of any facts that would make the information or projections incomplete or misleading. Cantor Fitzgerald assumed that the executed Merger Agreement would not differ in any material respect from the draft reviewed by Cantor Fitzgerald.

In arriving at its opinion, Cantor Fitzgerald did not perform or obtain any independent appraisal of the assets or liabilities (contingent or otherwise) of the Company, nor was Cantor Fitzgerald furnished with any such appraisals. Cantor Fitzgerald was asked by the Board of Directors to solicit indications of interest from various third parties regarding a transaction with the Company, and considered the results of such solicitation in rendering its opinion. Cantor Fitzgerald assumed that the Merger will be consummated in a timely manner and in accordance with the terms of the Merger Agreement without any limitations, restrictions, conditions, amendments or modifications, regulatory or otherwise, that would be material in any respect to its analysis or its opinion. Cantor Fitzgerald is not a legal, regulatory, tax or accounting expert and relied on the assessments made by the Company and its advisors with respect to such issues. Cantor Fitzgerald’s opinion did not address any legal, regulatory, tax or accounting matters.

It was understood that Cantor Fitzgerald’s opinion was intended for the benefit and use of the Board of Directors (in its capacity as such) in connection with its consideration of the Merger, and may not be used for any other purpose, reproduced, disseminated, quoted from or referred to at any time, in whole or in part, without the prior written consent of Cantor Fitzgerald. However, Cantor Fitzgerald’s opinion may be included in its entirety in this proxy statement. Cantor Fitzgerald’s opinion did not constitute a recommendation to the Board of Directors in connection with the Merger, nor did the opinion constitute a recommendation to any holders of Common Stock should vote or act with respect to the Merger or any related matter. Cantor Fitzgerald’s opinion did not address the Company’s underlying business decision to pursue the Merger, the relative merits of the Merger as compared to any alternative business or financial strategies that might exist for the Company or the effects of any other transaction in which the Company might engage. Cantor Fitzgerald did not express any opinion as to the price or range of prices at which the shares of Common Stock might trade subsequent to the announcement of the Merger. Cantor Fitzgerald’s opinion only addressed the fairness, from a financial point of view, to the holders of Common Stock (other than Sanofi and its

affiliates) of the Common Stock Merger Consideration and did not address any other term, aspect or implication of the Merger, including, without limitation, the form or structure of the Merger. In addition, Cantor Fitzgerald did not express any view or opinion as to the fairness, financial or otherwise, of the amount or nature of any compensation payable to or to be received by any of the Company’s officers, directors or employees, or any class of such persons, in connection with the Merger relative to the Common Stock Merger Consideration or otherwise.

Cantor Fitzgerald’s opinion was authorized for issuance by Cantor Fitzgerald’s Fairness Opinion and Valuation Committee. Cantor Fitzgerald’s opinion was subject to the assumptions, limitations, qualifications and other conditions contained therein and was necessarily based on economic, market and other conditions, and the information made available to Cantor Fitzgerald, as of the date of its opinion. Cantor Fitzgerald assumed no responsibility for updating or revising its opinion based on circumstances or events occurring after the date of Cantor Fitzgerald’s opinion.

In connection with rendering its opinion to the Board of Directors, Cantor Fitzgerald performed a variety of financial and comparative analyses, which are summarized below. The following summary is not a complete description of all analyses performed and factors considered by Cantor Fitzgerald in connection with its opinion. The preparation of a financial opinion is a complex process involving subjective judgments and is not necessarily susceptible to partial analysis or summary description. With respect to the selected companies and selected precedent transactions analyses summarized below, no company or transaction used as a comparison was identical to the Company or the Merger. These analyses necessarily involve complex considerations and judgments concerning financial and operating characteristics and other factors that could affect the public trading or acquisition values of the companies concerned. For purposes of the analyses described below, implied multiples for selected companies and selected transactions that were considered not meaningful or were not publicly available were not included in the high, mean, median and low multiples for the selected companies and the selected transactions.

Cantor Fitzgerald believes that its analyses and the summary below must be considered as a whole and that selecting portions of its analyses and factors or focusing on information presented in tabular format, without considering all analyses and factors or the narrative description of the analyses, could create a misleading or incomplete view of the processes underlying Cantor Fitzgerald’s analyses and opinion. Cantor Fitzgerald did not draw, in isolation, conclusions from or with regard to any one factor or method of analysis for purposes of its opinion, but rather arrived at its ultimate opinion based on the results of all analyses undertaken by it and assessed as a whole.

The estimates of the future performance of the Company in or underlying Cantor Fitzgerald’s analyses are not necessarily indicative of future results or values, which may be significantly more or less favorable than those estimates. In performing its analyses, Cantor Fitzgerald considered industry performance, general business and economic conditions and other matters, many of which were beyond the control of the Company. Estimates of the financial value of companies do not purport to be appraisals or necessarily reflect the prices at which companies or securities actually may be sold or acquired.

The Common Stock Merger Consideration was determined through negotiation between the Company and Sanofi, and the decision by the Company to enter into the Merger Agreement was solely that of the Board of Directors. Cantor Fitzgerald’s opinion and financial analyses were only one of many factors considered by the Board of Directors in its evaluation of the Merger and should not be viewed as determinative of the views of the Board of Directors or the Company’s management with respect to the Merger or the consideration payable in the Merger.

The following is a brief summary of the material financial analyses performed by Cantor Fitzgerald in connection with its opinion. The order in which such summary is presented does not represent the relative importance of such analyses. In addition, the financial analyses summarized below include information presented in tabular format. In order to fully understand Cantor Fitzgerald’s financial analyses, the tables must be read together with the text of each summary. The tables alone do not constitute a complete description of the financial analyses. Considering the data below without considering the full narrative description of the financial analyses, including the methodologies and assumptions underlying the analyses, could create a misleading or incomplete view of Cantor Fitzgerald’s financial analyses.

In the financial analyses summarized below, financial data of the selected companies were based on publicly available research analysts’ estimates, public filings and other publicly available information, financial data of the selected transactions were based on public filings and other publicly available information, and financial data of the Company were based on internal estimates of the Company’s management provided to Cantor Fitzgerald.

Selected Companies Analysis. Cantor Fitzgerald reviewed selected financial and stock market data of the Company and ten selected publicly traded late-stage rare disease biopharmaceutical companies (the “selected companies”).

Cantor Fitzgerald reviewed enterprise values of the selected companies, calculated as fully diluted equity values based on closing stock prices on September 3, 2021, less cash, plus debt, plus non-controlling interest, plus preferred equity, plus other contingent liabilities, as multiples of calendar year 2026 estimated revenue (“2026E Revenue”), which ranged from 0.42x to 4.67x. The mean and median revenue multiples observed in this analysis for the selected companies were 1.69x and 1.26x, respectively.

The selected companies and the financial data reviewed included the following:

Cantor Fitzgerald then applied a selected range of 2026E revenue multiples of 1.00x to 3.00x, derived from the selected companies, to corresponding data of the Company. Cantor Fitzgerald then adjusted for the Company’s estimated cash, debt, convertible preferred stock and other liabilities, and divided by the number of fully-diluted shares of Common Stock (determined using the treasury stock method and taking into account outstanding in-the-money options) as of September 3, 2021. This analysis indicated an implied per share equity value reference range for the Company of approximately $2.73 to $7.27, as compared to the Common Stock Merger Consideration of $9.50.

Selected Precedent Transactions Analysis. Cantor Fitzgerald reviewed, to the extent publicly available, financial information for ten selected transactions which involved late-stage rare disease biopharmaceutical target companies.

Cantor Fitzgerald reviewed enterprise values of the selected transactions, calculated as the purchase prices paid for the target companies’ equity (excluding contingent consideration, if any), less cash, plus debt, plus non-controlling interest, plus preferred equity, plus other contingent liabilities, on a standalone basis and as a multiple of estimated revenue for the calendar year approximately five years after the date each transaction was announced (“Estimated 5-Year Forward Revenue”).

The enterprise values of the selected transactions observed in this analysis ranged from $834 million to $3,365 million, and the mean and median enterprise values were $1,743 million and $1,465 million, respectively. The enterprise values of the selected transactions as a multiple of Estimated 5-Year Forward Revenue after the date each transaction was announced ranged from 1.67x to 6.73x, and the mean and median enterprise values as a multiple of Estimated 5-Year Forward Revenue were 3.02x and 2.43x, respectively.

The selected transactions considered, the date each transaction was announced and the financial data reviewed for each transaction were as follows:

Cantor Fitzgerald applied a selected range of enterprise values of $1,250 million to $2,000 million, derived from the selected transactions. Cantor Fitzgerald then adjusted for the Company’s estimated cash, debt, convertible preferred stock and other liabilities, and divided by the number of fully-diluted shares of Common Stock (determined using the treasury stock method and taking into account outstanding in-the-money options) as of September 3, 2021. This analysis indicated an implied per share equity value reference range for the Company of approximately $6.66 to $10.25, as compared to the Common Stock Merger Consideration of $9.50.

Cantor Fitzgerald also applied a selected range of 2026E revenue multiples of 2.25x to 4.25x, derived from the selected transactions, to the Company’s 2026E revenue, based on internal estimates of the Company’s management. Cantor Fitzgerald then adjusted for the Company’s estimated cash, debt, convertible preferred stock and other liabilities, and divided by the number of fully-diluted shares of Common Stock (determined using the treasury stock method and taking into account outstanding in-the-money options) as of September 3, 2021. This analysis indicated an approximate implied per share equity value reference ranges for the Company of $5.63 to $10.01, as compared to the Common Stock Merger Consideration of $9.50.

Discounted Cash Flow Analysis. Cantor Fitzgerald performed a discounted cash flow analysis of the Company based on internal estimates provided by the Company’s management and Cantor Fitzgerald’s calculation of probability of success adjusted, after-tax unlevered free cash flows set forth in “—Company Projections”.

In performing this analysis, Cantor Fitzgerald calculated a range of equity values for the Common Stock by (a) discounting to present value using discount rates ranging from 9.5% to 11.5% (reflecting the Company’s estimated weighted average cost of capital, which was derived using the Capital Asset Pricing Model and a size premium) and the mid-year convention: (i) the forecasted probability of success adjusted, after-tax unlevered free cash flows of the Company over the period beginning on October 1, 2021 and ending on December 31, 2034, utilized by Cantor Fitzgerald as set forth in “—Company Projections” and (ii) an implied terminal value of the Company, calculated assuming that the Company’s after-tax unlevered free cash flows would decline in perpetuity after December 31, 2034 at a range of rates of 60% to 10% year-over-year, and (b) adjusting for (1) the Company’s estimated cash, debt, convertible preferred stock and other liabilities and (2) the estimated value of the Company’s early-stage oncology platform based on a select set of companies.

For purposes of estimating the value of the Company’s early-stage oncology platform, Cantor Fitzgerald reviewed selected financial and stock market data of seven selected early-stage immuno-oncology biopharmaceutical companies (the “selected immuno-oncology companies”).

Cantor Fitzgerald reviewed enterprise values of the selected immuno-oncology companies, calculated as fully diluted equity values based on closing stock prices on September 3, 2021, less cash, plus debt, plus non-controlling interest, plus preferred equity, plus other contingent liabilities. The enterprise values of the selected immuno-oncology companies observed in this analysis ranged from $25 million to $350 million, and the mean and median enterprise values were $237 million and $281 million, respectively.

The selected immuno-oncology companies and the financial data reviewed included the following:

Based on its analysis of the selected immuno-oncology companies, Cantor Fitzgerald included a selected enterprise value of $200 million for the Company’s oncology platform.

Using the sum of the estimated valuations summarized above, Cantor Fitzgerald then divided by the number of fully-diluted shares of Common Stock (determined using the treasury stock method and taking into account outstanding in-the-money options) as of September 3, 2021. This analysis indicated an implied per share equity value reference range for the Company of approximately $8.33 to $11.99, as compared to the Common Stock Merger Consideration of $9.50.

Other Information. In rendering its opinion, Cantor Fitzgerald also reviewed and considered the historical trading prices of Common Stock during the one-year period ended September 3, 2021, which reflected low and high closing prices for Common Stock during such period of $3.15 and $5.73, respectively.

The Board of Directors selected Cantor Fitzgerald as one of the Company Financial Advisors in connection with the Merger based on Cantor Fitzgerald’s reputation as a leading global provider of advisory and capital markets services, experience in the life sciences industry and expertise in mergers and acquisitions, as well as its familiarity with the Company.

Cantor Fitzgerald has acted as a financial advisor to the Company in connection with the Merger and will receive a fee, based upon a percentage of the transaction value of the Merger, of approximately $15 million, $1.5 million of which was payable upon delivery of Cantor Fitzgerald’s opinion to the Board of Directors and the remaining balance of which is contingent upon the consummation of the Merger. In addition, the Company has agreed to indemnify Cantor Fitzgerald against certain liabilities arising out of its engagement.

During the two years preceding the date of Cantor Fitzgerald’s opinion, Cantor Fitzgerald has provided certain investment banking and other services to the Company on matters unrelated to the Merger, including acting as the placement agent for the Company’s ongoing at-the-market offering program, acting as the sole bookrunner for the Company’s private offering of the Convertible Notes in February 2021, executing two block trades on behalf of the Company in October 2019 and May 2020, and acting as the joint bookrunner for the Company’s public offering of Common Stock in November 2019, for which it has received aggregate fees of approximately $6.5 million. During the two years preceding the date of Cantor Fitzgerald’s opinion, Cantor Fitzgerald has not provided any financial advisory or other investment banking services to Sanofi for which Cantor Fitzgerald has received fees.

Consistent with applicable legal and regulatory requirements, Cantor Fitzgerald has adopted certain policies and procedures to establish and maintain the independence of Cantor Fitzgerald’s research departments and personnel. As a result, Cantor Fitzgerald’s research analysts may hold views, make statements or investment recommendations and/or publish research reports with respect to the Company, Sanofi, the Merger and other participants in the Merger that differ from the views of Cantor Fitzgerald’s investment banking personnel.

Cantor Fitzgerald may seek to provide the Company and Sanofi and their respective affiliates with certain investment banking and other services unrelated to the Merger in the future. In the ordinary course of business, Cantor Fitzgerald and its affiliates may actively trade (for their own accounts and for the accounts of their customers) certain equity and debt securities, bank debt and/or other financial instruments issued by the Company and/or Sanofi and their respective affiliates, as well as derivatives thereof, and, accordingly, may at any time hold long or short positions in such securities, bank debt, financial instruments and derivatives.

At a meeting of the Board of Directors held on September 7, 2021 to evaluate and approve the Merger, Moelis rendered its oral opinion to the Board of Directors, confirmed by the delivery of a written opinion dated September 7, 2021, addressed to the Board of Directors to the effect that, as of the date of such opinion and based upon and subject to the assumptions made, procedures followed, matters considered and limitations on the review undertaken, the Common Stock Merger Consideration to be received in the Merger by the holders of Common Stock (other than Sanofi and its affiliates and holders of Excluded Shares) was fair from a financial point of view to such holders.

The full text of Moelis’ written opinion dated September 7, 2021, which sets forth the assumptions made, procedures followed, matters considered and limitations on the review undertaken in connection with the opinion, is attached as Annex D to this proxy statement and is incorporated herein by reference. Moelis’ opinion was provided for the use and benefit of the Board of Directors (solely in its capacity as such) in its evaluation of the Merger. Moelis’ opinion is limited solely to the fairness, from a financial point of view, of the Common Stock Merger Consideration to be received by the holders of Common Stock (other than Sanofi and its affiliates and holders of Excluded Shares) in the Merger and does not address the Company’s underlying business decision to effect the Merger or the relative merits of the Merger as compared to any alternative business strategies or transactions that might be available to the Company. Moelis’ opinion does not constitute a recommendation as to how any holder of securities should vote or act with respect to the Merger or any other matter. Moelis’ opinion was approved by a Moelis fairness opinion committee.

In arriving at its opinion, Moelis, among other things:

In connection with its review, with the consent of the Board of Directors, Moelis relied on the information supplied to, discussed with or reviewed by it for purposes of its opinion being complete and accurate in all material respects. Moelis did not assume any responsibility for independent verification of, and did not independently verify, any of such information. With the consent of the Board of Directors, Moelis relied upon, without independent verification, the assessment of the Company and its legal, tax, regulatory and accounting advisors with respect to legal, tax, regulatory and accounting matters. With respect to the Financial Forecasts, Moelis assumed, at the direction of the Board of Directors, that they were reasonably prepared on a basis reflecting the best currently

available estimates and judgments of the Company’s management as to the future performance of the Company. In addition, with the consent of the Board of Directors, Moelis relied on the assessments of the management of the Company as to the existing pharmaceutical products then under development by the Company and the validity of, and risks associated with, the then existing and future products of the Company, including the risks and timing of regulatory approvals and commercialization of such products. Moelis expressed no view as to the reasonableness of the Financial Forecasts and other financial forecasts or the assumptions on which they were based. In addition, with the consent of the Board of Directors, Moelis did not make any independent evaluation or appraisal of any of the assets or liabilities (contingent, derivative, off-balance-sheet, or otherwise) of the Company, nor was Moelis furnished with any such evaluation or appraisal.

Moelis’ opinion did not address the Company’s underlying business decision to effect the Merger or the relative merits of the Merger as compared to any alternative business strategies or transactions that might be available to the Company and did not address any legal, regulatory, tax or accounting matters. At the direction of the Board of Directors, Moelis was not asked to, nor did it, offer any opinion as to any terms of the Merger Agreement or any aspect or implication of the Merger, except for the fairness of the Common Stock Merger Consideration from a financial point of view to the holders of Common Stock (other than Sanofi and its affiliates and holders of Excluded Shares). Moelis did not express any opinion as to fair value or the solvency of the Company following the closing of the Merger. Moelis noted that, pursuant to the Merger Agreement, the Excluded Shares will not be converted into the right to receive the Merger Consideration, and Moelis expressed no opinion with respect to such shares or as to the fairness of the Merger Consideration to holders thereof. In addition, Moelis expressed no opinion with respect to the treatment of the Preferred Stock in the Transaction, or the fairness of the Preferred Stock Merger Consideration relative to the treatment of such Preferred Stock. In rendering its opinion, Moelis assumed, with the consent of the Board of Directors, that the final executed form of the Merger Agreement would not differ in any material respect from the draft that Moelis reviewed, that the Merger would be consummated in accordance with its terms without any waiver or modification that could be material to Moelis’ analysis, that the representations and warranties of each party contained in the Merger Agreement were true and correct and that the parties to the Merger Agreement would comply with all the material terms of the Merger Agreement. Moelis assumed, with the consent of the Board of Directors, that all governmental, regulatory or other consents or approvals necessary for the completion of the Merger would be obtained, except to the extent that could not be material to Moelis’ analysis.

Moelis’ opinion was necessarily based on economic, monetary, market and other conditions as in effect on, and the information made available to Moelis as of, the date of its opinion, and Moelis assumed no responsibility to update its opinion for developments after the date of its opinion.

Moelis’ opinion did not address the fairness of the Merger or any aspect or implication of the Merger to, or any other consideration of or relating to, the holders of any class of securities, creditors or other constituencies of the Company, other than the fairness of the Common Stock Merger Consideration from a financial point of view to the holders of Common Stock (other than Sanofi and its affiliates and holders of Excluded Shares). In addition, Moelis did not express any opinion as to the fairness of the amount or nature of any compensation to be received by any officers, directors or employees of any parties to the Merger, or any class of such persons, relative to the Merger Consideration or otherwise. Moelis’ opinion was approved by a Moelis fairness opinion committee.

The following is a summary of the material financial analyses prepared by Moelis for the Board of Directors in connection with rendering its written opinion, dated September 7, 2021. Some of the summaries of financial analyses below include information presented in tabular format. In order to fully understand Moelis’ analyses, the tables must be read together with the text of each summary. The tables alone do not constitute a complete description of the analyses. Considering the data described below without considering the full narrative description of the financial analyses, including the methodologies and assumptions underlying the analyses, could create a misleading or incomplete view of Moelis’ analyses.

Unless the context indicates otherwise, stock prices are based on closing stock prices on September 2, 2021. For purposes of, among other things, deriving per share implied equity values for the Company, Moelis calculated certain per share amounts for the Company based on diluted shares outstanding as of September 3, 2021 provided by Company management and approved for use by Moelis in rendering its opinion.

For purposes of its analyses, Moelis reviewed a number of financial metrics, including the following:

Unless the context indicates otherwise, (i) the estimates of the future financial performance for the selected publicly traded companies listed below were based on certain publicly available research analyst estimates for those companies, and (ii) the estimates of the future financial performance of the Company relied upon for the financial analyses described below were based on the Financial Forecasts.

Moelis performed a discounted cash flow analysis of the Company using the Financial Forecasts and other information and data provided by the Company’s management to calculate the present value of the estimated future probability-adjusted unlevered after-tax free cash flows projected to be generated by the Company and the present value of the Company’s estimated terminal value, taking into account the estimated December 31, 2021 cash balance (net of debt) and the present value of the Company’s federal and state net operating losses and federal research and development tax credits.

Moelis utilized a range of discount rates of 8.25% to 10.75% based on an estimated range of the Company’s weighted average cost of capital (“WACC”). The estimated WACC range was derived using the Capital Assets Pricing Model and a size premium. Moelis used the foregoing range of discount rates to calculate the present values as of December 31, 2021 of (i) the Company’s estimated after-tax unlevered free cash flows for calendar years 2022 through 2034 (in each case, discounted using the mid-year discounting convention to a transaction date of December 31, 2021) and (ii) the estimated terminal values derived by applying a perpetuity growth rate range of (75%) to (25%) to the Company’s estimated terminal year after-tax unlevered free cash flow, which were added to the Company’s estimated December 31, 2021 net cash balance for purposes of determining equity and per share value.

Based on the foregoing, Moelis derived implied per share value ranges for the Common Stock of $8.50 to $12.21 per share. Moelis compared the implied per share value range to the Common Stock Merger Consideration of $9.50 per share.

Moelis conducted a sum-of-the-parts selected publicly traded companies analysis by separately reviewing financial and stock market information relating to selected publicly traded companies that, in Moelis’ professional judgment, have products similar to the Company’s KD025 product and its immuno-oncology platform. Based on its professional judgment and experience, Moelis selected publicly traded companies which are (1) biopharma companies with a single lead molecule that was recently approved or filed, targeting niche, specialty or orphan market opportunities and that otherwise have assets with a similar technology profile to the Company’s lead product and deemed generally relevant by Moelis in certain respects to the Company (such companies, the “KD025 Group”) or (2) platform immuno-oncology companies in Phase 1 or earlier with a core technology focus on small molecule and/or antibody programs and deemed generally relevant by Moelis in certain respects to the Company (the “IO Platform Group”). The following table indicates the companies reviewed by Moelis with respect to each of these groups:

Financial data for the selected companies was based on publicly available consensus research analyst estimates, public filings and other publicly available information and included, as appropriate, pro forma adjustments for acquisitions and divestitures, unfunded pension liabilities or other corporate events, which are referred to collectively as the “pro forma adjustments,” to the extent applicable. In the case of estimated TEV and 2026 Sales for the Company, Moelis reviewed both median consensus research analyst estimates and the Financial Forecasts. Although none of the selected companies is directly comparable to the Company, the companies included were selected because they are companies that, for purposes of analysis, had certain operational and financial characteristics that may be considered reasonably comparable in certain respects to the Company.

Moelis reviewed, among other things, the TEV of each of the each of the companies in the KD025 Group, each company in the KD025 Group’s median consensus estimates of sales for calendar year 2026 (“2026 Sales”) and the TEV of each of the KD025 Group companies as a multiple of 2026 Sales. The following table summarizes the results of the analysis of the selected companies in the KD025 Group:

Moelis also reviewed, among other things, for each company in the IO Platform Group, the TEV of each of the selected companies in the IO Platform Group. The following table summarizes the results of the analysis of the selected companies in the IO Platform Group:

In reviewing the characteristics of the selected publicly traded companies in the KD025 Group for purposes of determining reference ranges to apply to the Company’s estimated financial metrics, Moelis noted that its estimate of a range of total enterprise values for the Company’s KD025 asset as a stand-alone business was informed by a review of the mean and median TEV of the KD025 Group and its estimate of a range of total TEV/2026 Sales multiples for the Company’s KD025 asset as a stand-alone business was informed by a review of the TEV/2026 Sales multiples of each company in the KD025 Group. While considered, Moelis did not utilize data for ChemoCentryx and Calliditas in its determination of the TEV/2026 Sales multiple reference range because Moelis, in its professional judgment, assessed that those companies had faced recent clinical development challenges which made them not comparable to the Company. In addition, while considered, Moelis did not utilize data for BioCryst in its determination of the TEV/2026 Sales multiple reference range because Moelis, in its professional judgment, assessed that BioCryst’s multiple strong quarters of commercial execution on ORLADEYO and robust pipeline made it not comparable to the Company. Based on the foregoing analysis and its professional judgment and experience, Moelis selected (i) a reference range for estimated TEV/2026 Sales multiples for the Company’s KD025 asset as a stand-alone business of 1.50x to 2.25x and (ii) a reference range of TEV for the Company’s KD025 asset as a stand-alone business of $1 billion to $2 billion.

In reviewing the characteristics of the selected publicly traded companies in the IO Platform Group for purposes of determining its reference ranges to apply to the Company’s estimated financial metrics, Moelis noted that its estimate of a range of total enterprise values for the Company’s IO Platform assets as a stand-alone business was informed by a review of the mean and median TEV of each company in the IO Platform Group. Moelis further noted that certain other platform immuno-oncology companies were excluded from the IO Platform Group because such companies have multiple ongoing clinical programs or platform validating partnerships with larger pharmaceutical companies. Based on the foregoing analysis and its professional judgment and experience, Moelis selected a reference range of TEV for the Company’s IO Platform assets as a stand-alone business of $175 million to $350 million.

Moelis then (i) applied the reference range for estimated TEV/2026 Sales multiples to the Company’s estimated 2026 Sales as set forth in the Company Projections to calculate an implied enterprise value for the Company’s KD025 asset and (ii) added the reference range of enterprise value for the Company’s IO Platform assets on a stand-alone basis to generate an implied TEV for the Company. This analysis indicated an implied per share value ranges for the Common Stock of $4.73 to $7.25 per share. Moelis compared the implied per share value ranges to the Common Stock Merger Consideration of $9.50 per share.

Moelis also (1) applied the reference range for the enterprise value of the Company’s KD025 asset as a stand-alone business and (2) added the reference range of enterprise value for the Company’s IO Platform assets on a stand-alone basis to generate an implied TEV for the Company. This analysis indicated an implied per share value ranges for the Common Stock of $6.24 to $11.74 per share. Moelis compared the implied per share value ranges to the Common Stock Merger Consideration of $9.50 per share.

Moelis reviewed financial information for selected precedent transactions announced since 2015 involving acquired companies that focused on niche or orphan market opportunities, that had its lead program in late-stage clinical trials or approved and/or that had a lead asset with a similar technology profile to the Company’s lead asset, which Moelis determined, in its professional judgment and experience, were generally relevant in certain respects to the Company (the “Selected Precedent Transactions”). Moelis reviewed, among other things, transaction values of the Selected Precedent Transactions and enterprise value as a multiple of CY+5 Sales for each Selected Precedent Transaction. For purposes of this summary, “CY+5 Sales” means estimated sales amounts (i) for marketed companies, in the applicable calendar year plus five years or (ii) for clinical-stage companies, assumed launch plus five years, in each case, based on the public filings made by each of the acquired companies (with the exception of Clementia Pharmaceutical Inc., which is based on equity research estimates at the time of the transaction announcement) in connection with the applicable Selected Precedent Transaction. Financial data for the relevant transactions were based on publicly available information relating to the relevant transaction.

The Selected Precedent Transactions used in this analysis and their implied TEV to CY+5 Sales multiples are summarized in the following table:

In reviewing the characteristics of the Selected Precedent Transactions for purposes of selecting reference ranges of TEV to apply to the Company’s estimated financial metrics, Moelis noted that its reference range was informed by the Selected Precedent Transactions, other than the Sanofi/Principia transaction which had a transaction value at a premium to other Selected Precedent Transactions due to the broad platform potential of Principia’s lead asset at the time of acquisition. Moelis also noted that in reviewing the characteristics of the Selected Precedent Transactions for purposes of selecting reference ranges of multiples to CY+5 Sales to apply to the Company’s estimated financial metrics, Moelis’ reference range was informed by the Selected Precedent Transactions, other than the (i) Horizon/Viela transaction since Viela was acquired at a premium due to its deep mid-stage biologics pipeline, and (ii) BridgeBio/Eidos transaction since Eidos was acquired at a premium due to the value of its discovery platform.

Based on the foregoing analysis and its professional judgment and experience, Moelis selected (i) a reference range of 1.50x to 3.00x TEV / CY+5 Sales multiples and (ii) a reference range for the Company’s TEV of $1.5 billion to $2.5 billion. Moelis then applied the reference range for estimated CY+5 Sales multiples to the Company’s estimated 2026 Sales as set forth in the Financial Forecasts, which analysis indicated an implied per share value range for the Common Stock of $3.85 to $7.23 per share. Moelis compared the implied per share value ranges to the Common Stock Merger Consideration of $9.50 per share.

Moelis also applied the reference range for the Company’s implied enterprise value which analysis indicated an implied per share value range for the Common Stock of $7.82 to $12.35 per share. Moelis compared the implied per share value ranges to the Common Stock Merger Consideration of $9.50 per share.

Moelis also noted for the Board of Directors the following additional factors that were not considered part of Moelis’ financial analyses with respect to its opinion, but were referenced for informational purposes: (i) the historic intraday trading prices for the Common Stock during the 52-week period ended September 2, 2021, which reflected low and high stock prices during such period of $3.15 and $5.73 per share, as compared to the Common Stock Merger Consideration of $9.50 per share, (ii) the one-year forward stock price targets for the Common Stock in recently published, publicly available equity research analysts’ reports, which indicated low and high stock price targets ranging from $9.00 to $20.00 per share, as compared to the Common Stock Merger Consideration of $9.50 per share, and (iii) an analysis of unaffected premiums paid since January 1, 2019 in 25 acquisitions in the biotech industry with a transaction size in excess of $1 billion and excluding transactions in which the acquirer held an existing stake – based on such premiums paid analysis, Moelis applied a reference range of premia from 60% to 80% to the Company’s closing share price on September 2, 2021, which resulted in an implied low and high per share value range for the Common Stock of $8.66 to $9.74 per share, as compared to the Common Stock Merger Consideration of $9.50 per share.

The foregoing is a summary of the analyses undertaken by Moelis in connection with Moelis’ opinion. The preparation of a fairness opinion is a complex analytical process and is not necessarily susceptible to partial analysis or summary description. Selecting portions of the analyses or summary set forth above, without considering the analyses as a whole, could create an incomplete view of the processes underlying Moelis’ opinion. In arriving at its fairness determination, Moelis considered the results of all of its analyses and did not attribute any particular weight to any factor or analysis. Rather, Moelis made its fairness determination on the basis of its experience and professional judgment after considering the results of all of its analyses. No company or transaction used in the analyses described above is identical to the Company or the Merger. In addition, such analyses do not purport to be appraisals, nor do they necessarily reflect the prices at which businesses or securities actually may be sold. Analyses based upon forecasts of future results are not necessarily indicative of actual future results, which may be significantly more or less favorable than suggested by such analyses. Because the analyses described above are inherently subject to uncertainty, being based upon numerous factors or events beyond the control of the parties or their respective advisors, neither the Company nor Moelis or any other person assumes responsibility if future results are materially different from those forecast.

The Merger Consideration was determined through arm’s-length negotiations between the Company and Sanofi and was approved by the Board of Directors. Moelis did not recommend any specific consideration to the Company or the Board of Directors, or that any specific amount or type of consideration constituted the only appropriate consideration for the transaction. The Board of Directors selected Moelis as one of its financial advisors in connection with the Merger based on Moelis’ reputation and experience. Moelis is an internationally recognized investment banking firm that has substantial experience in transactions similar to the Merger. Pursuant to a letter agreement dated August 13, 2021, Moelis acted as financial advisor to the Company in connection with the Merger and will receive a fee for its services, estimated to be approximately $15 million in the aggregate based on the information available as of the date of announcement of the Merger, $1.5 million of which was earned in connection with the delivery of Moelis’ opinion dated September 7, 2021, in connection with the Board of Directors’ consideration of the Merger, regardless of the conclusion reached therein, and the remainder of which is contingent upon completion of the Merger. Furthermore, the Company has agreed to reimburse Moelis for certain expenses and to indemnify Moelis for certain liabilities, including liabilities under the federal securities laws, arising out of its engagement.

Moelis’ affiliates, employees, officers and partners may at any time own securities (long or short) of the Company and Sanofi. In the past two years, Moelis has not provided investment banking or other services to the Company or Sanofi. Moelis may, in the future, provide investment banking or other services to the Company, Sanofi or other parties involved in the Merger and would expect to receive compensation for such services.

The Company does not, as a matter of course, publicly disclose projections as to its future financial performance. However, in connection with the strategic and financial review process as described in this proxy statement, management prepared certain unaudited forecasts (the “Company Projections”), which were provided to and adopted by the Board of Directors, and also provided to and, with the consent of the Board of Directors, relied upon by Cantor

Fitzgerald and Moelis for use in connection with their respective financial analyses and fairness opinions, but were not provided to parties potentially interested in a transaction with the Company. The Company Projections included prospective financial information for the Company on a standalone basis.

The Company Projections were not prepared with a view to public disclosure and are included in this proxy statement only because the Company Projections were made available to Cantor Fitzgerald and Moelis for use in connection with their respective financial analyses and fairness opinions. The Company Projections were not prepared with a view to compliance with (1) generally accepted accounting principles in the U.S. (“GAAP”) or any other jurisdiction, (2) the published guidelines of the SEC regarding projections and forward-looking statements; or (3) the guidelines established by the American Institute of Certified Public Accountants for preparation and presentation of prospective financial information. Neither the Company’s independent registered public accounting firm, nor any other independent accountants, have audited, reviewed, compiled, examined, or performed any procedures with respect to the Company Projections or expressed any opinion or given any form of assurance with respect thereto or their achievability. The report of the Company’s independent registered public accounting firm incorporated by reference relates to the Company’s historical audited financial information only and does not extend to the prospective financial information and should not be read to do so. The summary of the Company Projections is included solely to give stockholders of the Company access to certain financial projections that were made available to, and relied upon by, the Board of Directors, Cantor Fitzgerald and Moelis.

Although a summary of the Company Projections is presented with numerical specificity, the Company Projections reflect numerous assumptions and estimates as to future events made by the Company’s management that management believed were reasonable at the time the Company Projections were prepared, taking into account the relevant information available to the Company’s management at the time. However, this information should not be relied upon as being necessarily indicative of actual future results. Important factors that may affect actual results and cause the Company Projections not to be achieved include general economic conditions, regulatory conditions, financial market conditions, the Company’s ability to achieve forecasted sales, accuracy of certain accounting assumptions, changes in actual or projected cash flows, competitive pressures and changes in tax laws or accounting treatment. The Company Projections also reflect assumptions as to certain business decisions that are subject to change. In addition, the Company Projections do not take into account any circumstances or events occurring after the date that they were prepared and do not give effect to the Merger. As a result, there can be no assurance that the Company Projections will be realized, and actual results may be materially better or worse than those contained in the Company Projections. The Company Projections cover multiple years, and such information by its nature becomes less reliable with each successive year.

The inclusion of the Company Projections in this proxy statement should not be regarded as an indication that the Board of Directors, the Company, Cantor Fitzgerald, Moelis or any of their respective affiliates or representatives or any other recipient of this information considered, or now considers, the Company Projections to be predictive of actual future results. The summary of the Company Projections is not included in this proxy statement in order to induce any stockholder to vote in favor of the Merger Proposal or any of the other proposals to be voted on at the Special Meeting or for any other purpose. We do not intend to update or otherwise revise the Company Projections to reflect circumstances existing after the date when made or to reflect the occurrence of future events, even in the event that any or all of the assumptions underlying the Company Projections are shown to be in error or no longer appropriate, except as otherwise required by law. In light of the foregoing factors and the uncertainties inherent in the Company Projections, stockholders are cautioned not to place undue reliance on the projections included in this proxy statement.

None of the Company, Sanofi or any of their respective affiliates, advisors, officers, directors or representatives has made or makes any representation to any Company stockholder or other person regarding the ultimate performance of the Company compared to the information contained in the Company Projections or that the Company Projections will be achieved. The Company has made no representation to Sanofi or Merger Sub, in the Merger Agreement or otherwise, concerning the Company Projections.

The Company Projections and the accompanying tables contain PoS (probability of success) adjusted net sales revenue, EBIT (earnings before interest and taxes) and unlevered free cash flow, each of which may be considered a non-GAAP financial measure within the meaning of applicable rules and regulations of the SEC. The Company believes these measures are helpful in understanding its past financial performance and future results. These financial measures are not meant to be considered in isolation or as a substitute for the comparable GAAP measure and should be read in conjunction with the Company’s consolidated financial statements prepared in accordance with GAAP.

The Company Projections include assumptions related to revenue, costs and cash flows:

The following table summarizes the Company Projections. The Company Projections are forward-looking statements. For information on factors that may cause the Company’s future results to materially vary, see the information under the section captioned “Cautionary Statement Regarding Forward-Looking Statements.”

The following tables summarize the Company’s unlevered free cash flow, as calculated by Cantor Fitzgerald and Moelis based on the Company Projections.

Unlevered Free Cash Flow (as calculated by Cantor Fitzgerald):

Unlevered Free Cash Flow (as calculated by Moelis):

As noted above, the Company Projections reflect numerous estimates and assumptions made with respect to industry performance, general business, economic, regulatory, market and financial conditions and other future events, as well as matters specific to our business, all of which are difficult to predict and many of which are beyond our control.

We anticipate that the total funds needed by Sanofi and Merger Sub to (1) pay our stockholders and holders of equity awards the amounts due to them under the Merger Agreement and (2) pay related fees and expenses in connection with the Merger and associated transactions will be approximately $1.9 billion in the aggregate.

We believe Sanofi’s cash on hand will be sufficient to complete the Merger and pay related fees and expenses in connection with the Merger and associates transactions and repay or refinance the outstanding indebtedness of the Company that will be payable as a result of the Merger, but we cannot assure you of that. Those amounts may be insufficient if, among other things, the fees, expenses or other amounts required to be paid in connection with the Merger are greater than anticipated.

Each of Sanofi and Merger Sub have expressly acknowledged and agreed that the closing and the consummation of the Merger is not conditioned on the availability of any financing arrangements.

The Merger Agreement provides that the closing of the Merger will take place no later than the second business day after the satisfaction or waiver of the conditions to closing of the Merger (described below under the caption “The Merger Agreement—Conditions to the Closing of the Merger”) (other than those conditions that by their terms are to be satisfied at the closing of the Merger, but subject to the satisfaction or waiver of such conditions at the closing of the Merger) or such other time agreed to in writing by Sanofi and us.

Promptly following the Effective Time, the Exchange Agent will send to each holder of record of shares of Common Stock at the Effective Time, a letter of transmittal and instructions advising stockholders how to surrender stock certificates and book-entry shares in exchange for the Common Stock Merger Consideration. Promptly following the Effective Time, Sanofi will pay each holder of Preferred Stock the Preferred Stock Merger Consideration payable in respect of their shares of Preferred Stock.

You should not return your stock certificates with the enclosed proxy card, and you should not forward your stock certificates to the Exchange Agent without a letter of transmittal.

If you are a holder of record of shares of Common Stock, you will not be entitled to receive the Common Stock Merger Consideration until (1) any certificate representing such shares of Common Stock is surrendered to the Exchange Agent, together with a properly completed letter of transmittal or (2) an “agent’s message” is received by the Exchange Agent in respect of any such shares that are uncertificated and held in book-entry form.

The letter of transmittal will include instructions if you have lost a share certificate or if such certificate has been stolen or destroyed. If any stock certificate shall have been lost, stolen or destroyed, then before you will be entitled to receive the Common Stock Merger Consideration, you will have to make an affidavit of that fact claiming such stock certificate to be lost, stolen or destroyed and, if required by Sanofi, post a bond, in such reasonable amount as Sanofi may direct, as indemnity against any claim that may be made against it with respect to such stock certificate.

In considering the recommendation of the Board of Directors with respect to the Merger, you should be aware that executive officers and directors of the Company may have certain interests in the Merger that may be different from, or in addition to, the interests of the Company’s stockholders generally, as more fully described below. The Board of Directors was aware of and considered these interests to the extent that they existed at the time, among other matters, in evaluating the Merger and in recommending that the Merger Agreement be adopted by the stockholders of the Company.

As of the date of this proxy statement, none of our executive officers has entered into any agreement with Sanofi or any of its affiliates regarding employment with, or the right to purchase or participate in the equity of, the Surviving Corporation or one or more of its affiliates. Prior to or following the closing of the Merger certain of our executive officers may have discussions, or may enter into agreements with, Sanofi or Merger Sub or their respective affiliates regarding employment with the Surviving Corporation or one or more of its affiliates.

The Surviving Corporation and its subsidiaries will honor and fulfill in all respects the obligations of the Company and its subsidiaries under any indemnification agreements existing as of the Agreement Date between the Company or any of its subsidiaries and any of their respective current or former directors and officers for a period of six years following the Effective Time.

The Surviving Corporation will indemnify, defend and hold harmless current or former directors and officers of the Company and its subsidiaries with respect to all acts or omissions by them in their capacities as such or any transactions contemplated by the Merger Agreement for a period of six years following the Effective Time. During such six-year time period, Sanofi also will cause the certificate of incorporation, bylaws or other organizational documents of the Surviving Corporation and its subsidiaries to contain provisions with respect to indemnification, exculpation and advancement of expenses for acts, errors, omissions and service prior to the Effective Time that are

at least as favorable to the current or former directors and officers of the Company and its subsidiaries as those set forth in the Company’s and its subsidiaries’ organizational documents as of the Agreement Date and will not amend, repeal or otherwise modify these provisions in the organizational documents in any manner except as required by law.

The Merger Agreement also provides that, prior to the Effective Time, the Company will purchase a six-year “tail” policy and the Surviving Corporation will maintain such “tail” policy in full force and effect and continue to honor the obligations under the “tail” policy. This obligation is subject to an annual premium cap of 300% of the annual premium paid by the Company prior to the Effective Time. For more information see “The Merger Agreement—Indemnification and Insurance.”

Following the Agreement Date, (i) with respect to any outstanding Offering Period(s) (as defined in the Company’s ESPP) under the Company ESPP as of the Agreement Date, no participant in the Company ESPP may increase the percentage amount of his or her payroll deduction election in effect on the Agreement Date for such Offering Period and no new participants may participate in such Offering Period; (ii) no new Offering Period will commence under the Company ESPP on or after the Agreement Date; (iii) any Offering Period under the Company ESPP that does not end prior to the Effective Time will terminate and a Subscription Date (as such term is defined in the Company ESPP) will occur under the Company ESPP immediately prior to the Effective Time with respect to such Offering Period, in which case any shares of Common Stock purchased under the Offering Period will be treated the same as all other shares of Common Stock; and (iv) immediately prior to the Effective Time, the Company ESPP will terminate. To the extent our executive officers participate in the Company ESPP, they will be entitled to the treatment described above.

The following table sets forth the number of shares of Common Stock, Preferred Stock, Company Options, Company SARs and Company EARs that are currently held by each of the Company’s executive officers and

non-employee directors, and the amounts that would be realized (subject to any required tax withholdings or deductions) by such individuals with respect to these shares based on the Common Stock Merger Consideration assuming that the closing of the Merger occurred on September 17, 2021, which is the assumed closing date only for purposes of this compensation-related disclosure. The table below does not take into account or attempt to forecast any grants, additional issuances, purchases, sales or forfeitures of equity interests following September 17, 2021.

We have entered into employment agreements (“Employment Agreements”) with each of Harlan W. Waksal, M.D., Steven Meehan, and Gregory S. Moss, our executive officers. On September 7, 2021, in connection with the approval of the Merger Agreement and the transactions contemplated thereby, the Board approved certain amendments to the Employment Agreements. The following descriptions of the terms of the Employment Agreements, as amended, with our executive officers are intended as a summary only and are qualified in their entirety by reference to the employment agreements filed as exhibits to our Annual Report on Form 10-K for the year ended December 31, 2020, which was filed with the SEC on March 4, 2021, and the amendments to the Employment Agreements that were filed as exhibits to our Current Report on Form 8-K filed on September 8, 2021.

The Employment Agreements, as amended, provide for the payment of retention bonuses in the amount of $3,500,000 to Dr. Waksal, $1,000,000 to Mr. Meehan and $1,000,000 to Mr. Moss (the “Retention Bonuses”). The Retention Bonuses were paid 25% on the date the Merger Agreement was fully executed and the remaining 75% will be earned on the Closing Date, subject to the executive’s continuous and active employment with the Company through such date unless his employment is terminated without Cause or he resigns with Good Reason (as such terms are defined in the Employment Agreements, as amended) prior to such date.

The Employment Agreements, as amended, also provide for severance payments to Dr. Waksal and Messrs. Meehan and Moss in the event the executive’s employment is terminated without Cause, or he resigns with Good Reason, in either case during the three months prior to, as of, or within 12 months following the effective date of a Change in Control (as defined in the executive’s employment agreement as amended). If Dr. Waksal’s employment is so terminated, he will be entitled to receive severance in the form of a lump sum payment equal to 36 months’ base salary plus the target bonus amount and continued healthcare coverage for 36 months. If Mr. Meehan’s or Mr. Moss’s employment is so terminated, he will be entitled to receive severance in the form of a lump payment equal to 24 months’ base salary plus the target bonus amount and continued healthcare coverage for 24 months. In addition, the Employment Agreements, as amended, provide that all outstanding equity grants will accelerate and vest upon the earlier of the date such executive’s employment is terminated or the closing date of a Change in Control. The

Company will also pay each such executive a tax gross-up payment in respect of any excise taxes incurred by such executive under Section 4999 of the Internal Revenue Code that are triggered as a result of the consummation of a Change in Control.

The following is a summary of the material U.S. federal income tax consequences of the Merger to “U.S. holders” and “non-U.S. holders” (each as defined below) whose shares of Common Stock or Preferred Stock are converted into the right to receive cash in the Merger. This summary is for general information purposes only and does not purport to consider all aspects of U.S. federal income taxation that might be relevant to our stockholders. This discussion is based the Internal Revenue Code of 1986, as amended (the “Code”), existing and temporary U.S. Treasury regulations promulgated thereunder, judicial opinions, and administrative rulings and published positions of the Internal Revenue Service (the “IRS”), each as in effect as of the date hereof. These laws and authorities are subject to change or differing interpretations, possibly on a retroactive basis, and any such change could affect the accuracy of the statements and conclusions set forth in this summary. As a result, the Company cannot assure stockholders that the tax considerations described in this summary will not be challenged by the IRS or would be sustained by a court if challenged by the IRS. We have not sought, and do not intend to seek, any ruling from the IRS or any tax opinion of counsel with respect to the statements made and the conclusions reached in the following summary. Accordingly, the discussion below neither binds the IRS nor precludes it from adopting a contrary position.

The summary applies only to beneficial owners who hold shares of Common Stock or Preferred Stock as capital assets within the meaning of Section 1221 of the Code (generally, property held for investment purposes), and does not address the tax considerations for holders of Common Stock or Preferred Stock subject to special treatment under U.S. federal income tax law, including, without limitation, the following:

This summary does not address any aspect of state, local or non-U.S. tax laws, any estate or gift tax considerations, the application of the alternative minimum tax or any U.S. federal non-income taxes (including, for example, the Medicare contribution tax on net investment income that may be imposed under the Code) or any other form of taxation that may be applicable to a stockholder. Furthermore, it generally does not address the tax consequences of transactions effectuated before, after, or at the same time as the Merger, whether or not they are in connection with the Merger. Finally, this summary does not address the tax considerations to holders of Company Equity Awards with respect to their Company Equity Awards. Accordingly, Company stockholders are urged to consult their own tax advisors as to the specific tax consequences to them of the Merger, including the applicable federal, state, local, and non-U.S. tax laws.

If a partnership (including an entity or arrangement treated as a partnership for U.S. federal income tax purposes) holds Common Stock or Preferred Stock, the tax treatment of a partner of such partnership (or member of such other entity treated as a partnership) generally will depend on the status of the partner (or member) and the activities of the partner (or member) and the partnership (or such other entity treated as a partnership). A partner of a partnership (or member of such other entity treated as a partnership) holding Common Stock or Preferred Stock should consult the partner (or member)’s tax advisor regarding the U.S. federal income tax consequences of the Merger to such partner (or member).

For purposes of this summary, a “U.S. holder” is any beneficial owner of shares of Common Stock or Preferred Stock that is, for U.S. federal income tax purposes:

The exchange of shares of Common Stock or Preferred Stock for cash in the Merger will be a taxable transaction for U.S. federal income tax purposes. In general, a U.S. holder whose shares of Common Stock or Preferred Stock are converted into the right to receive cash in the Merger will recognize capital gain or loss for U.S. federal income tax purposes equal to the difference, if any, between the amount of cash received with respect to such shares (determined before the deduction of any applicable withholding taxes, as described below under “—Backup Withholding and Information Reporting”) and the U.S. holder’s adjusted tax basis in such shares. A U.S. holder’s adjusted tax basis will generally equal the price the U.S. holder paid for such shares. The amount, character, and timing of such gain or loss generally will be determined separately with respect to each block of stock owned by such U.S. holder. For purposes of the foregoing, a block of stock is generally composed of those shares of a particular class of stock of a company that were acquired at the same time and at the same price. Each U.S. holder should consult such U.S. Holder’s tax advisors regarding the manner in which any cash received pursuant to the Merger should be allocated among the U.S. Holder’s respective different blocks of Common Stock and/or Preferred Stock. Any capital gain or loss will be long-term capital gain or loss, provided that the U.S. holder’s holding period for such shares of Common Stock or Preferred Stock is more than 12 months at the Effective Time and otherwise should be short-term capital gain or loss. Long-term capital gains of non-corporate U.S. holders are generally subject to a reduced tax rate and short-term capital gains are generally subject to tax at ordinary income tax rates. There are limitations on the deductibility of capital losses.

A “non-U.S. holder” is a beneficial owner of Common Stock or Preferred Stock that is not a U.S. holder or a partnership (or any other entity or arrangement that is treated as a partnership for U.S. federal income tax purposes). In such case, a non-U.S. holder whose shares of Common Stock or Preferred Stock are exchanged for cash in the Merger generally is not expected to be subject to U.S. federal income tax on any gain realized on such sale or exchange unless:

A non-U.S. holder described in the first bullet point immediately above will be subject to regular U.S. federal income tax on any gain realized as if the non-U.S. holder were a U.S. holder, subject to an applicable income tax treaty providing otherwise. If such non-U.S. holder is a corporation, it may also be subject to a branch profits tax equal to 30% (or a lower treaty rate) of its effectively connected earnings and profits for the taxable year, as adjusted for certain items. A non-U.S. holder described in the second bullet point immediately above will be subject to U.S. federal income tax at a rate of 30% (or a lower rate specified by an applicable income tax treaty between the United States and such non-U.S. holder’s country of residence) on any gain realized, which may be offset by U.S.-source capital losses, if any, provided that the non-U.S. holder has timely filed U.S. federal income tax returns with respect to such losses.

We believe we are not and have not been a “United States real property holding corporation” for U.S. federal income tax purposes at any time during the five-year period preceding the Merger.

Backup withholding of tax (currently at the rate of 24%) may apply to cash payments to which a non-corporate U.S. holder is entitled under the Merger Agreement, unless such U.S. holder provides a taxpayer identification number, certifies that such number is correct and it is not subject to backup withholding on IRS Form W-9, and otherwise complies with the backup withholding rules. Each of our U.S. holders that is a stockholder of record should complete and sign, under penalty of perjury, the Form W-9 included as part of the letter of transmittal and return it to the Exchange Agent, in order to provide the information and certification necessary to avoid backup withholding, unless an exemption applies and is established in a manner satisfactory to the Exchange Agent. A non-U.S. holder that is a stockholder of record and provides the Exchange Agent with the applicable Form W-8 providing certification of non-U.S. status (such as a Form W-8BEN, W-8BEN-E or another appropriate version of Form W-8) will generally establish an exemption from backup withholding. A U.S. holder that fails to provide its correct taxpayer identification number and the appropriate certifications, fail to establish an exemption as described above, or falsely certifies that it is not subject to backup withholding generally will be subject to backup withholding and may be subject to penalties imposed by the IRS.

Amounts withheld pursuant to the backup withholding rules are not an additional tax. Any amounts withheld from cash payments to a stockholder pursuant to the Merger under the backup withholding rules will generally be allowable as a refund or a credit against such stockholder’s U.S. federal income tax liability provided the required information is timely furnished to the IRS. If there is withholding on a payment to a U.S. holder and the withholding results in an overpayment of taxes, the affected U.S. holder should consult with such U.S. holder’s own tax advisor regarding whether and how any refund might be obtained with respect to the amounts so withheld.

The U.S. federal income tax consequences described above are for general information purposes only and are not intended to constitute a complete description of all tax consequences relating to the Merger. Because individual circumstances may differ, each stockholder should consult the stockholder’s tax advisor regarding the applicability of the rules discussed above to the stockholder, the particular tax effects to the stockholder of the Merger in light of such stockholder’s particular circumstances and the application of state, local and foreign tax laws, if applicable.

Under the terms of the Merger Agreement, the Merger cannot be completed until, following the submission of required filings with the relevant governmental authorities, the waiting period applicable to the consummation of the Merger under the HSR Act has expired or been terminated, and neither Sanofi nor the Company shall have received a standard form letter from the FTC, in the form announced and disclosed by the FTC on August 3, 2021, for which the Parties shall not have been notified by the FTC that the underlying investigation has been closed or otherwise resolved.

On September 20, 2021, the Company and Sanofi filed notification of the proposed Merger with the FTC and DOJ under the HSR Act.

Although we expect that all required regulatory clearances and approvals will be obtained, we cannot assure you that these regulatory clearances and approvals will be timely obtained or obtained at all or that the granting of these regulatory clearances and approvals will not involve the imposition of additional conditions on the completion of the Merger, including the requirement to divest assets, or require changes to the terms of the Merger Agreement. These conditions or changes could result in the conditions to the Merger not being satisfied on a timely basis or at all.

This section describes the material terms of the Merger Agreement. The descriptions of the Merger Agreement in this section and elsewhere in this proxy statement are not complete and are qualified in their entirety by reference to the complete text of the Merger Agreement, a copy of which is attached as Annex A and is incorporated by reference into this proxy statement. You are encouraged to read the Merger Agreement carefully and in its entirety before making any decisions regarding the Merger, including approval of the Merger Proposal, as it is the legal document governing the Merger. This section is not intended to provide you with any factual information about the Company, Sanofi or Merger Sub. Such information can be found elsewhere in this proxy statement and in the public filings the Company makes with the SEC, as described under the heading “Where You Can Find More Information” beginning on page [85] of this proxy statement.

The following summary describes the material provisions of the Merger Agreement. The rights and obligations of the parties under the Merger Agreement are governed by the express terms of the Merger Agreement and not by this summary or any other information contained in this proxy statement.

The representations, warranties, covenants and agreements described below and included in the Merger Agreement (1) were made only for purposes of the Merger Agreement and as of specific dates; (2) were made solely for the benefit of the parties to the Merger Agreement; and (3) may be subject to important qualifications, limitations and supplemental information agreed to by Sanofi, Merger Sub and the Company in connection with negotiating the terms of the Merger Agreement. The representations and warranties may also be subject to a contractual standard of materiality different from those generally applicable to reports and documents filed with the SEC and in some cases were qualified by confidential matters disclosed to Sanofi and Merger Sub by the Company in connection with the Merger Agreement. In addition, the representations and warranties may have been included in the Merger Agreement for the purpose of allocating contractual risk between the Company, Sanofi and Merger Sub rather than to establish matters as facts, and may be subject to standards of materiality applicable to such parties that differ from those applicable to investors. Stockholders are not third-party beneficiaries under the Merger Agreement and should not rely on the representations, warranties, covenants and agreements or any descriptions thereof as characterizations of the actual state of facts or condition of the Company, Sanofi or Merger Sub or any of their respective affiliates or businesses. Moreover, information concerning the subject matter of the representations and warranties may change after the Agreement Date. In addition, you should not rely on the covenants in the Merger Agreement as actual limitations on the respective businesses of the Company, Sanofi and Merger Sub, because the parties may take certain actions that are either expressly permitted in the confidential Company disclosure letter to the Merger Agreement (the “Company Disclosure Letter”) or as otherwise consented to by the appropriate party, which consent may be given without prior notice to the public. The Merger Agreement is described below, and included as Annex A, only to provide you with information regarding its terms and conditions, and not to provide any other factual information regarding the Company, Sanofi, Merger Sub or their respective businesses. Accordingly, the representations, warranties, covenants and other agreements in the Merger Agreement should not be read alone, and you should read the information provided elsewhere in this document and in our filings with the SEC regarding the Company and our business.

Upon the terms and subject to the conditions of the Merger Agreement, at the Effective Time, Merger Sub will merge with and into the Company in accordance with the DGCL. The Company will be the Surviving Corporation in the Merger, will become a wholly owned indirect subsidiary of Sanofi and will continue to exist following the Merger. As a result of the Merger, the Company will cease to be a publicly traded company. In addition, the Common Stock will subsequently be delisted from NASDAQ and deregistered under the Exchange Act, and we will no longer file periodic reports with the SEC.

At the Effective Time, the certificate of incorporation and bylaws of the Surviving Corporation will be amended and restated as provided in the Merger Agreement. The directors and officers of the Surviving Corporation will, from and after the Effective Time, be the individuals who are the directors and officers of the Merger Sub immediately prior to the Effective Time.

The closing of the Merger will take place no later than the second business day after the satisfaction or waiver of the conditions to closing of the Merger (described below under the caption “The Merger Agreement – Conditions to the Closing of the Merger”) (other than those conditions that by their terms are to be satisfied at the closing of the Merger, but subject to the satisfaction or waiver of such conditions at the closing of the Merger) or such other time agreed to in writing by Sanofi and us. At the closing of the Merger, the Company will file a certificate of merger with the Secretary of State of the State of Delaware as provided under the DGCL. The Merger will become effective upon the filing of the certificate of merger or at such later time as is agreed by the parties to the Merger Agreement and specified in the certificate of merger.

In the Merger, each outstanding share of Common Stock outstanding immediately prior to the Effective Time (other than Excluded Shares) will be canceled and cease to exist and converted into the right to receive the Common Stock Merger Consideration, which is an amount in cash equal to $9.50, without interest thereon. At the Effective Time of the Merger, each share of Preferred Stock issued and outstanding as of immediately prior to the Effective Time (other than Dissenting Shares) will be canceled and cease to exist and automatically convert into the right to receive the Preferred Stock Merger Consideration, which is an amount in cash in equal to the greater of (i) the Stated Liquidation Preference Amount (as defined in the Company’s Certificate of Designation dated July 26, 2016) plus any dividends (whether or not earned or declared) accrued and unpaid thereon from the last Dividend Payment Date (as defined in the Certificate of Designation) through the closing date of the Merger and (ii) the amount that would be payable per share of Preferred Stock if such share of Preferred Stock had been converted to Common Stock immediately prior to the effective time of the Merger.

As a result of the Merger, the treatment of the Company’s equity awards that are outstanding immediately prior to the Effective Time will be as follows:

As of immediately prior to the Effective Time, and conditioned upon the occurrence of the Effective Time, and without any action on the part of any holder of Company Options, (i) all unvested Company Options which are outstanding as of immediately prior to the Effective Time shall fully vest and become exercisable Company Options, and (ii) to the extent not exercised prior to the Effective Time, each Company Option shall be canceled at the Effective Time, with the former holder of such canceled Company Option becoming entitled to receive in consideration of the cancellation of such Company Option, the Company Option Merger Consideration, which is an amount in cash equal to: (A) the excess, if any, of the Common Stock Merger Consideration over the exercise price per share of such Company Option; multiplied by (B) the number of shares of Common Stock underlying such Company Option. If the exercise price per share of any Company Option is equal to or greater than the Common Stock Merger Consideration, such Company Option shall be canceled and terminated without any consideration in respect thereof. Sanofi shall cause the Surviving Corporation to pay the Company Option Merger Consideration, without interest thereon and subject to deduction for any required withholding taxes, at the Effective Time or at the Company’s next ordinary course payroll date (but in no event later than 20 business days after the Effective Time).

As of immediately prior to the Effective Time, and conditioned upon the occurrence of the Effective Time, and without any action on the part of any holder of Company SARs, all unvested Company SARs which are outstanding as of immediately prior to the Effective Time will fully vest and become exercisable Company SARs, and each Company SAR that is outstanding immediately prior to the Effective Time will be canceled at the Effective Time, with the former holder of such canceled Company SAR becoming entitled to receive, in consideration of the cancellation of such Company SAR, the Company SAR Merger Consideration, which is an amount in cash equal to (A) the excess, if any, of the Common Stock Merger Consideration over the exercise price of such Company SAR multiplied by (B) the number of shares of Common Stock subject to such Company SAR. If the exercise price of any Company SAR is equal to or greater than the Common Stock Merger Consideration, such Company SAR shall be

canceled and terminated without any consideration in respect thereof. Sanofi will cause the Surviving Corporation to pay the Company SAR Merger Consideration, without interest thereon and subject to deduction for any required withholding taxes, at the Effective Time or at the Company’s next ordinary course payroll date (but in no event later than 20 business days after the Effective Time).

As of immediately prior to the Effective Time, and conditioned upon the occurrence of the Effective Time, and without any action on the part of any holder of Company EARs, all unvested Company EARs which are outstanding as of immediately prior to the Effective Time will fully vest, and each Company EAR that is outstanding immediately prior to the Effective Time will be canceled at the Effective Time, with the former holder of such Company EAR becoming entitled to receive, in consideration of the cancellation of such Company EAR, the Company EAR Merger Consideration, which is an amount in cash equal to (A) the excess, if any, of the Common Stock Merger Consideration over the base price of such Company EAR multiplied by (B) the number of shares of Common Stock subject to such Company EAR. If the base price per share of any Company EAR is equal to or greater than the Common Stock Merger Consideration, such Company EAR shall be canceled and terminated without any consideration in respect thereof. Sanofi shall cause the Surviving Corporation to pay the Company EAR Merger Consideration, without interest thereon and subject to deduction for any required withholding taxes, at the Effective Time or at the Company’s next ordinary course payroll date (but in no event later than 20 business days after the Effective Time).

Following the Agreement Date, (i) with respect to any outstanding Offering Period (as defined in the Company ESPP) under the Company ESPP as of the Agreement Date, no participant in the Company ESPP may increase the percentage amount of his or her payroll deduction election in effect on the Agreement Date for such Offering Period and no new participants may participate in such Offering Period; (ii) no new Offering Period will commence under the Company ESPP on or after the Agreement Date; (iii) any Offering Period under the Company ESPP that does not end prior to the Effective Time will terminate and a Subscription Date (as such term is defined in the Company ESPP) will occur under the ESPP immediately prior to the Effective Time with respect to such Offering Period, in which case any shares of Company Common Stock purchased under the Offering Period will be treated the same as all other shares of Company Common Stock in the Merger; and (iv) immediately prior to the Effective Time, the Company ESPP will terminate.

Prior to the Effective Time, Sanofi will appoint an agent reasonably acceptable to us (the “Exchange Agent”) to make payments of the Merger Consideration to stockholders. At or prior to the Effective Time, Sanofi shall provide or cause to be provided to the Exchange Agent cash sufficient to pay the aggregate Merger Consideration to stockholders (less any Merger Consideration in respect of any Excluded Shares and Preferred Stock).

Promptly following the Effective Time, the Exchange Agent will send to each holder of record of shares of Common Stock at the Effective Time, a letter of transmittal and instructions advising stockholders how to surrender stock certificates and book-entry shares in exchange for the Merger Consideration. Promptly following the Effective Time, Sanofi will pay each holder of Preferred Stock the Preferred Stock Merger Consideration payable in respect of their shares of Preferred Stock.

You should not return your stock certificates with the enclosed proxy card, and you should not forward your stock certificates to the Exchange Agent without a letter of transmittal.

Each holder of shares of Common Stock that have been converted into the right to receive the Merger Consideration shall be entitled to receive, upon (1) surrender to the Exchange Agent of the certificate representing such shares of Common Stock, together with a properly completed letter of transmittal or (2) receipt of an “agent’s message” by the Exchange Agent (or such other evidence of transfer as the Exchange Agent may reasonably request) in the case of a book-entry transfer of uncertificated shares, the Common Stock Merger Consideration in respect of the Common Stock represented by such certificate or uncertificated shares. The amount of any Common Stock Merger Consideration paid to the stockholders may be reduced by any applicable withholding taxes.

If any cash deposited with the Exchange Agent is not claimed within one year following the Effective Time, such cash will be returned to Sanofi, upon demand, and any holders of Common Stock who have not complied with the

exchange procedures in the Merger Agreement will thereafter look only to Sanofi for payment of the Merger Consideration in respect of such shares without any interest thereon. Any cash deposited with the Exchange Agent that remains unclaimed immediately prior to the time at which such amounts would otherwise become property of a Governmental Authority will, to the extent permitted by applicable law, become the property of Sanofi free and clear of any claims or interest of any person previously entitled thereto.

If any stock certificate shall have been lost, stolen or destroyed, then before such stockholder will be entitled to receive the Merger Consideration, such stockholder will have to make an affidavit of that fact claiming such stock certificate to be lost, stolen or destroyed and, if required by Sanofi, deliver a written indemnity agreement in form and substance reasonably acceptable to Sanofi.

Stockholders are entitled to appraisal rights under the DGCL in connection with the Merger. This means that you are entitled to have the fair value of your shares of Common Stock or Preferred Stock determined by the Delaware Court of Chancery and to receive payment based on that valuation in lieu of the Merger Consideration if you follow exactly the procedures specified under the DGCL. The ultimate amount you receive in an appraisal proceeding may be less than, equal to or more than the amount you would have received under the Merger Agreement.

To exercise your appraisal rights, you must submit a written demand for appraisal to the Company before the vote is taken on the Merger Agreement and you must not vote (either in person or by proxy) in favor of the proposal to adopt the Merger Agreement. Your failure to follow exactly the procedures specified under the DGCL may result in the loss of your appraisal rights. See “Appraisal Rights” beginning on page [79] and the text of the Delaware appraisal rights statute reproduced in its entirety as Annex B to this proxy statement. If you hold your shares of Common Stock through a bank, brokerage firm or other nominee and you wish to exercise appraisal rights, you should consult with your bank, brokerage firm or other nominee to determine the appropriate procedures for the making of a demand for appraisal by your bank, brokerage firm or other nominee.

THE PROCESS OF DEMANDING AND EXERCISING APPRAISAL RIGHTS REQUIRES STRICT COMPLIANCE WITH TECHNICAL PREREQUISITES. IF YOU WISH TO EXERCISE YOUR APPRAISAL RIGHTS, YOU SHOULD CONSULT WITH YOUR OWN LEGAL COUNSEL IN CONNECTION WITH COMPLIANCE UNDER SECTION 262 OF THE DGCL, THE FULL TEXT OF WHICH IS ATTACHED TO THIS PROXY STATEMENT AS ANNEX B.

The Merger Agreement contains representations and warranties of the Company, Sanofi and Merger Sub.

Some of the representations and warranties in the Merger Agreement made by the Company are qualified as to “materiality” or “Company Material Adverse Effect.” For purposes of the Merger Agreement, “Company Material Adverse Effect” means any event, effect, occurrence, fact, circumstance, condition or change that, individually or in the aggregate, has had or would be reasonably likely to have a material adverse effect on (a) the business, operations, condition (financial or otherwise) or results of operations of the Company and its subsidiaries, taken as a whole, or (b) the ability of the Company to consummate the transactions contemplated by the Merger Agreement; provided, however, none of the following will be deemed in and of themselves, either alone or in combination, to constitute, and except as provided below, none of the following will be taken into account in determining whether there is, or would reasonably be likely to be, a Company Material Adverse Effect:

In the Merger Agreement, the Company has made customary representations and warranties to Sanofi and Merger Sub that are subject, in some cases, to specified exceptions and qualifications contained in the Merger Agreement and the Company Disclosure Letter. These representations and warranties relate to, among other things:

In the Merger Agreement, Sanofi and Merger Sub have made customary representations and warranties to the Company that are subject, in some cases, to specified exceptions and qualifications contained in the Merger Agreement. These representations and warranties relate to, among other things:

The representations and warranties contained in the Merger Agreement will not survive the consummation of the Merger.

The Merger Agreement provides that, except (1) as expressly contemplated, required or expressly permitted by the Merger Agreement; (2) as required by applicable law; (3) as disclosed in the Company Disclosure Letter; (4) as approved by Sanofi in writing (which approval will not be unreasonably withheld, conditioned or delayed); or (5) for any actions taken reasonably and in good faith in response to COVID-19, during the period of time between the Agreement Date and the Effective Time, the Company will and will cause each of its subsidiaries to:

In addition, the Company has also agreed that, except as (1) expressly contemplated, required or permitted by the Merger Agreement; (2) as required by applicable law; (3) disclosed in the Disclosure Letter; (4) approved by Sanofi in writing (which approval will not be unreasonably withheld, conditioned or delayed); or (5) for actions taken reasonably and in good faith in response to COVID-19 during the period of time between the Agreement Date and the Effective Time, the Company will not, and will cause each of its subsidiaries not to, among other things:

From the Agreement Date until the earlier to occur of the termination of the Merger Agreement and the Effective Time, the Company has agreed not to, and to cause its subsidiaries and its and their respective directors and officers, and to direct other representatives not to:

Notwithstanding the restriction described above, at any time prior to the adoption of the Merger Agreement by the Company’s stockholders, the Company and its representatives may (i) provide information in response to a request therefor by a person who makes an unsolicited Acquisition Proposal if the Company did not violate the restrictions set forth above in any material respect in respect of such person and following the Agreement Date if (x) such Acquisition Proposal did not result from a violation of the restriction described above in any material respects, provided that the Company will substantially concurrently provide to Sanofi any nonpublic information concerning the Company that is provided to any such person given access which was not previously provided to Sanofi or its representatives, (y) prior to providing such information, the Company receives from such person an executed confidentiality agreement on terms that, taken as a whole, are no less favorable in the aggregate to the other party than those contained in the confidentiality agreement previously executed by the Company and Sanofi (it being understood that such confidentiality agreement need not contain a standstill provision or otherwise prohibit the making, or amendment, of an Acquisition Proposal and that does not prohibit the Company from providing any information to Sanofi or otherwise prohibit the Company from complying with its obligations under the Merger Agreement) and (z) the Company promptly (and in any event within 24 hours thereafter) makes available to Sanofi any non-public information concerning the Company or its subsidiaries that the Company provides to any such person that was not previously made available to Sanofi; (ii) engage or participate in any discussions or negotiations with any person who has made such an Acquisition Proposal; or (iii) authorize, adopt, approve, recommend or otherwise declare advisable or propose to authorize, adopt, approve, recommend or declare advisable (publicly or otherwise) such an Acquisition Proposal, if and only if, (A) prior to taking any action described in clause (i), (ii) or (iii) above, the Board of Directors determines in good faith (after consultation with the Company’s outside legal and

financial advisors) that the failure to take such action would be inconsistent with the directors’ fiduciary duties under applicable Law, (B) prior to taking any action described in clause (i) or (ii) above, the Board of Directors has determined in good faith based on information then available that such Acquisition Proposal either constitutes a Superior Proposal or is reasonably likely to result in a Superior Proposal and (C) in the case referred to in clause (iii) above, the Board of Directors determines in good faith that such Acquisition Proposal is a Superior Proposal.

For purposes of this proxy statement and the Merger Agreement: