UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

WASHINGTON, D.C. 20549

SCHEDULE 14A

(Rule14a-101)

SCHEDULE 14A INFORMATION

Proxy Statement Pursuant to Section 14(a) of the

Securities Exchange Act of 1934

Filed by the Registrant  ☒                         Filed by a Party other than the Registrant  ☐

Check the appropriate box:

SIERRA ONCOLOGY, INC.

(Name of Registrant as Specified In Its Charter)

N/A

(Name of Person(s) Filing Proxy Statement, if other than the Registrant)

Payment of Filing Fee (Check the appropriate box):

April 24, 202023, 2021

Dear Stockholder:

You are cordially invited to attend the 20202021 Annual Meeting of Stockholders of Sierra Oncology, Inc.Inc and any adjournment, postponement or other delay thereof (the “Annual Meeting”). The 20202021 Annual Meeting will be a virtual meeting of stockholders, which means you will be able to participate in the Annual Meeting and, vote during the Annual Meeting via live webcast by visitingwww.virtualshareholdermeeting.com/SRRA2020SRRA2021 on Tuesday, June 9, 20208, 2021 at 10:00 a.m. (Pacific Time).

The Securities and Exchange Commission rules allow companies to furnish proxy materials to stockholders over the internet. We have elected to do so, thus reducing the environmental impact and lowering the costs of printing and distributing proxy materials without impacting your timely access to this important information. On or about April 24, 2020,23, 2021, we expect to mail a Notice of Internet Availability of Proxy Materials (Notice of Internet Availability) containing instructions on how to access our proxy statement for our 2020 Annual Meeting of Stockholders and our 20192020 annual report onForm 10-K to stockholders. The Notice of Internet Availability also provides instructions on how to vote, and includes instructions on how to receive paper copies of the proxy materials by mail, or an electronic copy of the proxy materials by email, if desired.

The matters to be acted upon at the meeting are described in the accompanying notice of Annual Meeting and proxy statement.

Your vote is important.

Whether or not you plan to attend the meeting, please vote on the internet or by telephone, or request, sign and return a proxy card to ensure that your shares are represented at the meeting.

Sincerely,

Dr. Nick GloverStephen G. Dilly

President and Chief Executive Officer

SIERRA ONCOLOGY, INC.

c/o 2150 – 885 West Georgia Street1820 Gateway Drive, Suite 110

Vancouver, British Columbia V6C 3E8

CanadaSan Mateo, CA 94404

NOTICE OF ANNUAL MEETING OF STOCKHOLDERS

To Be Held on June 9, 20208, 2021

To Our Stockholders:

NOTICE IS HEREBY GIVEN that the 20202021 Annual Meeting of Stockholders of Sierra Oncology, Inc. will be held via live webcast by visitingwww.virtualshareholdermeeting.com/SRRA2020SRRA2021 on Tuesday, June 9, 20208, 2021 at 10:00 a.m. (Pacific Time).

We are holding the meeting for the following purposes, which are more fully described in the accompanying proxy statement:

In addition, stockholders may be asked to consider and vote upon such other business as may properly come before the meeting or any adjournment or postponement thereof. These items of business to be transacted at the Annual Meeting are more fully described in the Proxy Statement.

Only stockholders of record at the close of business on April 15, 202014, 2021 are entitled to receive notice of, and to vote at, the meeting and any adjournments thereof. To be admitted to the Annual Meeting atwww.virtualshareholdermeeting.com/SRRA2020SRRA2021, you must enter the control number found on your proxy card, voting instruction form or notice you previously received. You may vote during the Annual Meeting by following the instructions available on the meeting website during the meeting.

For ten days prior to the meeting, a complete list of the stockholders entitled to vote at the meeting will be available by written request for examination by any stockholder for any purpose relating to the meeting. Requests should be sent to: Sierra Oncology, Inc., Attention: Corporate Secretary, c/o 2150 – 885 West Georgia Street, Vancouver, British Columbia V6C 3E8, Canada.1820 Gateway Drive, Suite 110, San Mateo, CA 94404. The stockholder list will also be available during the virtual meeting viawww.virtualshareholdermeeting.com/SRRA2020SRRA2021.

Your vote as a Sierra Oncology, Inc. stockholder is very important. Each share of common stock that you own represents one vote.

For questions regarding your stock ownership, you may contact our Vice President, Corporate AffairsInvestor Relations at (604) 558-6536(415) 732-9828 or investors@sierraoncology.com or, if you are a registered holder, our transfer agent, American Stock Transfer & Trust Company, LLC by email through their website at https://www.astfinancial.com or by phone at (800) 937-5449. Whether or not you expect to attend the meeting, we encourage you to read the proxy statement and vote through the internet or by telephone, or to request, sign and return your proxy card as soon as possible, so that your shares may be represented at the meeting. For specific instructions on how to vote your shares, please refer to the section entitled “General Proxy Information” in the proxy statement and the instructions on the Notice of Internet Availability of Proxy Materials.

By Order of the Board of Directors,

Dr. Nick GloverStephen G. Dilly President and Chief Executive Officer

Vancouver, British ColumbiaSan Mateo, California

April 24, 202023, 2021

SIERRA ONCOLOGY, INC.

PROXY STATEMENT FOR 20202021 ANNUAL MEETING OF STOCKHOLDERS

TABLE OF CONTENTS

i

SIERRA ONCOLOGY, INC.

c/o 2150 – 885 West Georgia Street1820 Gateway Drive, Suite 110

Vancouver, British Columbia V6C 3E8

CanadaSan Mateo, CA 94404

PROXY STATEMENT FOR THE 20202021 ANNUAL MEETING OF STOCKHOLDERS

June 9, 20208, 2021

INFORMATION ABOUT SOLICITATION AND VOTING

The accompanying proxy is solicited on behalf of the Board of Directors of Sierra Oncology, Inc. (Sierra Oncology or the Company) for use at Sierra Oncology’s 20202021 Annual Meeting of Stockholders (Annual Meeting) to be held via live webcast atwww.virtualshareholdermeeting.com/SRRA2020SRRA2021 on Tuesday, June 9, 20208, 2021 at 10 a.m. (Pacific Time), and any adjournment or postponement thereof.

INTERNET AVAILABILITY OF PROXY MATERIALS

Under rules adopted by the Securities and Exchange Commission (SEC), we are furnishing proxy materials to our stockholders primarily via the internet, instead of mailing printed copies to each stockholder. On or about April 24, 2020,23, 2021, we expect to send to our stockholders a Notice of Internet Availability of Proxy Materials (Notice of Internet Availability) containing instructions on how to access our proxy materials, including our proxy statement and our annual report onForm 10-K. The Notice of Internet Availability also provides instructions on how to vote, and includes instructions on how to receive paper copies of the proxy materials by mail, or an electronic copy of the proxy materials by email.

This process is designed to reduce our environmental impact and lower the costs of printing and distributing our proxy materials while providing our stockholders timely access to this important information. If you would prefer to receive printed proxy materials, please follow the instructions included in the Notice of Internet Availability.

GENERAL INFORMATION ABOUT THE MEETING

Purpose of the Meeting

At the meeting, stockholders will act upon the proposals described in this proxy statement. In addition, we will consider any other matters that are properly presented for a vote at the meeting. We are not aware of any other matters to be submitted for consideration at the meeting. If any other matters are properly presented for a vote at the meeting, the persons named in the proxy, who are officers of the Company, have the authority in their discretion to vote the shares represented by the proxy.

Attending the Meeting

You will be able to attend the Annual Meeting virtually and vote your shares electronically at the meeting by visiting www.virtualshareholdermeeting.com/SRRA2021. To participate in the Annual Meeting, you will need the control number from your proxy card. The Annual Meeting webcast will begin promptly at 10 a.m. (Pacific Time). Online check-in will begin at 9:45 a.m. (Pacific Time) and you should allow ample time for the check-in procedures.

Record Date; Quorum

Only holders of record of common stock at the close of business on April 15, 2020,14, 2021, the record date, will be entitled to vote at the meeting. At the close of business on April 15, 2020, 10,395,73214, 2021, 12,349,961 shares of common stock were outstanding and entitled to vote. All share numbers in this proxy reflect the1-for-40 reverse stock split that we effected on January 22, 2020.

The holders of a majority of the voting power of the shares of stock entitled to vote at the meeting as of the record date must be present or represented by proxy at the meeting in order to hold the meeting and conduct business. This presence is called a quorum. Your shares are counted as present at the meeting if you are present and vote in person at the meeting or if you have properly submitted a proxy.

of either stockholder withholding or brokernon-votes will count for purposes of determining the presence of a quorum, but are not treated as votes cast and, therefore, will have no effect on the election of directors, or the ratification of the appointment of Deloitte & Touche LLP.LLP, the advisory resolution on the compensation of our named executive officers, or the proposed frequency of future advisory votes on the compensation of our named executive officers. Abstentions are voted neither “for” nor “against” a matter, and, therefore, will have no effect on the election of directors, or the ratification of the appointment of Deloitte & Touche LLP, the advisory resolution on the compensation of our named executive officers, or the proposed frequency of advisory votes on the compensation of our named executive officers, but are counted in the determination of a quorum.

Recommendations of the Board of Directors on Each of the Proposals Scheduled to be Voted on at the Meeting

The Board of Directors recommends that you votevote:

None

If you receive more than one proxy card or Notice of Internet Availability, your shares are registered in more than one name or are registered in different accounts. To make certain all of your shares are voted, please follow the instructions included on the Notice of Internet Availability on how to access and vote each proxy card. If you requested or received paper proxy materials by mail, please complete, sign, date and return each proxy card to ensure that all of your shares are voted.

Expenses of Soliciting Proxies

We will pay the expenses associated with soliciting proxies. Following the original distribution and mailing of the solicitation materials, we or our agents may solicit proxies by mail, email, telephone, facsimile, by other similar means, or in person. Our directors, officers and other employees, without additional compensation, may solicit proxies personally or in writing, by telephone, email or otherwise. Following the original distribution and mailing of the solicitation materials, we will request brokers, custodians, nominees and other record holders to forward copies of those materials to persons for whom they hold shares and to request authority for the exercise of proxies. In such cases, we, upon the request of the record holders, will reimburse such holders for their reasonable expenses. If you choose to access the proxy materials and/or vote through the internet, you are responsible for any internet access charges you may incur.

CORPORATE GOVERNANCE STANDARDS AND DIRECTOR INDEPENDENCE

We are committed to good corporate governance practices. These practices provide an important framework within which our Board of Directors and management pursue our strategic objectives for the benefit of our stockholders.

Corporate Governance Guidelines

Our Board of Directors has adopted Corporate Governance Guidelines that set forth expectations for directors, director independence standards, Board committee structure and functions, and other policies for the governance of the Company. Our Corporate Governance Guidelines are available without charge on the investor relations section of our website athttp://investor.sierraoncology.com/corporate-governance.

Board Composition and Leadership Structure

Mr. Robert Pelzer is the Chairman of our Board of Directors effective November 22, 2019. Mr. Donald Parfet served as the Chairman of our Board of Directors through November 22, 2019. The positions of Chief Executive Officer and Chairman of our Board of Directors are held by two different individuals (Dr. Nick GloverStephen G. Dilly and Mr. Robert Pelzer, respectively). This structure allows our Chief Executive Officer to focus on ourday-to-day business while our Chairman leads our Board of Directors in its fundamental role of providing advice to and independent oversight of management. Our Board of Directors believes such separation is appropriate, as it enhances the accountability of the Chief Executive Officer to the Board of Directors and strengthens the independence of the Board of Directors from management.

Board’s Role in Risk Oversight

The Board oversees the Company’s risk management process, including operational, financial, legal and regulatory, strategic and reputational risks. Our Board of Directors’ approach to risk oversight is designed to support the achievement of organizational objectives, including strategic objectives, to improve long-term organizational performance and enhance stockholder value. A fundamental part of our risk oversight is not only understanding the risks a company faces and what steps management is taking to manage those risks, but also understanding what level of risk is appropriate for us. In setting our business strategy, our Board of Directors assesses the various risks and mitigation strategies implemented by management and determines the appropriate level of risk for the Company.

Our Board of Directors believes that open communication between management and the Board of Directors is essential for effective risk management and oversight. Our Board of Directors meets with our Chief Executive Officer and other members of the senior management team at quarterly Board of Director meetings, where, among other topics, they discuss strategy and risks in the context of reports from the management team and evaluate the risks inherent in significant transactions. While our Board of Directors is ultimately responsible for risk oversight, our Board committees assist the Board of Directors in fulfilling its oversight responsibilities in certain areas of risk. The Audit Committee assists our Board of Directors in fulfilling its oversight responsibilities with respect to risk management in the areas of internal control over financial reporting and disclosure controls and procedures. The Compensation Committee assists our Board of Directors in assessing risks created by the incentives inherent in our compensation policies. The Nominating and Corporate Governance Committee assists our Board of Directors in fulfilling its oversight responsibilities with respect to the management of corporate, legal and regulatory risk.

While our Board of Directors oversees risk management, the Company’s management is charged with managing risk on a day-to-day basis. The Company believes it has strong internal processes and a robust internal control environment, which facilities the identification and management of risks and regular communication with our Board of Directors. These processes include regular management disclosure committee meetings, a Code of Conduct and Ethics and a robust compliance program.

Director Independence

Our common stock is listed on the Nasdaq Global Market. Under the rules of the Nasdaq Stock Market, independent directors must constitute a majority of a listed company’sCompany’s Board of Directors. In addition, the rules of the Nasdaq Stock Market require that, subject to specified exceptions, each member of a listed company’sCompany’s Audit, Compensation and Nominating and Corporate Governance Committees must be an “independent director”.director.” Under the rules of the Nasdaq Stock Market, a director will only qualify as an “independent director” if, in the opinion of that company’sCompany’s Board of Directors, that person does not have a relationship that would interfere with the exercise of independent judgment in carrying out the responsibilities of a director. Additionally, Compensation Committee members must not have a relationship with the listed company that is material to the director’s ability to be independent from management in connection with the duties of a Compensation Committee member.

Compensation Committee

Our Compensation Committee is composed of Mr. Pelzer, Dr. Aggarwal and Dr. Richardson. Mr. Pelzer is the Chair of our Compensation Committee. The composition of our Compensation Committee meets the requirements for independence under the current Nasdaq Stock Market and SEC rules and regulations. Our Compensation Committee is responsible for, among other things:

The Compensation Committee has the sole authority and responsibility, subject to any approval by the Board of Directors which the Compensation Committee or legal counsel determines to be desirable or required by applicable law or the Nasdaq rules, to determine all aspects of executive compensation packages for the Chief Executive Officer and other executive officers. The Compensation Committee also makes recommendations to our Board of Directors regarding the form and amount of compensation ofnon-employee directors. The Compensation Committee may take into account the recommendations of the Chief Executive Officer with respect to compensation of the other executive officers, and the recommendations of the Board of Directors or any member of the Board of Directors with respect to compensation of the Chief Executive Officer and other executive officers.

The Compensation Committee engaged an independent executive compensation consulting firm, Radford, an AON Hewitt Company (Radford), to evaluate our executive compensation program and practices and to provide advice and ongoing assistance on executive compensation matters for the fiscal year ended December 31, 2019.2020. Specifically, Radford was engaged to:

Representatives of Radford met informally with the Chair of the Compensation Committee and attended the regular meetings of the Compensation Committee, including executive sessions from time to time without any members of management present. During the fiscal year ended December 31, 2019,2020, Radford worked directly with the Compensation Committee (and not on behalf of management) to assist the committee in satisfying its responsibilities and undertook no projects for management without the committee’s prior approval. The Compensation Committee has determined that none of the work performed by Radford during the fiscal year ended December 31, 20192020 raised any conflict of interest.

CodesCode of Conduct and Ethics

Our Board of Directors has adopted a code of business conduct and ethics that applies to all of our employees, officers and directors, including our Chief Executive Officer, Chief Financial Officer and other executive and senior financial officers. We intend to disclose future amendments to certain provisions of our code of conduct, or waivers of these provisions, on our website or in public filings. The full text of our code of conduct is posted on the investor relations section of our website athttp://investor.sierraoncology.com/corporate-governance.

Compensation Committee Interlocks and Insider Participation

During 2019,2020, Mr. Pelzer, Dr. Aggarwal (effective December 12, 2019) and Dr. Richardson (effective December 12, 2019) served on our Compensation Committee. Mr. Nguyen, Dr. Onetto, Mr. Parfet served on our Compensation Committee through November 22, 2019. None of our current executive officers has served as a member of the Board of Directors, or as a member of the Compensation or similar committee, of any entity that has one or more executive officers who served on our Board of Directors or Compensation Committee during the fiscal year ended December 31, 2019. Mr. Parfet, a member of our Compensation Committee through November 22, 2019, served as our interim Chief Executive Officer from May 2014 to August 2014.2020.

Board and Committee Meetings and Attendance

The Board of Directors and its committees meet regularly throughout the year and also hold special meetings and act by written consent from time to time. During 2019,2020, the Board of Directors held eight meetings including telephonicseven meetings, the Audit Committee held four meetings, the Compensation Committee held twoeight meetings, and Corporate Governance Committee held threefive meetings, including telephonic meetings. During 2019,2020, none of the directors attended fewer than 75% of the aggregate of the total number of meetings held by the Board of Directors during his or her tenure and the total number of meetings held by all committees of the Board of Directors on which such director served during his or her tenure. The independent members of the Board of Directors also meet separately without management directors on a regular basis to discuss such matters as the independent directors consider appropriate.

Board Attendance at Annual Stockholders’ Meeting

We invite and encourage each member of our Board of Directors to attend our Annual Meetings of Stockholders. We do not have a formal policy regarding attendance of Annual Meetings by the members of our Board of Directors. ThreeSix of our directors attended our 20192020 Annual Meeting of Stockholders.

Communication with Directors

Stockholders and interested parties who wish to communicate with our Board of Directors,non-management members of our Board of Directors as a group, a committee of the Board of Directors or a specific member of our Board of Directors (including our Chairman) may do so by letters addressed to the attention of our Corporate Secretary, Sierra Oncology, Inc., c/o 2150 – 885 West Georgia Street, Vancouver, British Columbia V6C 3E8, Canada.1820 Gateway Drive, Suite 110, San Mateo, CA 94404.

identify and evaluate director nominees, with the goal of maintaining and further developing a diverse, experienced and highly qualified Board of Directors. Candidates may come to our attention through current members of our Board of Directors, professional search firms, stockholders or other persons.

The Nominating and Corporate Governance Committee will recommend to the Board of Directors for selection all nominees to be proposed by the Board of Directors for election by the stockholders, including approval or recommendation of a slate of director nominees to be proposed by the Board of Directors for election at each Annual Meeting of Stockholders, and will recommend all director nominees to be appointed by the Board of Directors to fill interim director vacancies.

Our Board of Directors encourages selection of directors who will contribute to the Company’s overall corporate goals. The Nominating and Corporate Governance Committee may from time to time review and recommend to the Board of Directors the desired qualifications, expertise and characteristics of directors, including such factors as business experience, diversity and personal skills in life sciences and biotechnology, finance, marketing, financial reporting and other areas that are expected to contribute to an effective Board of Directors. Exceptional candidates who do not meet all of these criteria may still be considered. In evaluating potential candidates for the Board of Directors, the Nominating and Corporate Governance Committee considers these factors in the light of the specific needs of the Board of Directors at that time.

In addition, under our Corporate Governance Guidelines, a director is expected to spend the time and effort necessary to properly discharge such director’s responsibilities. Accordingly, a director is expected to regularly attend meetings of the Board of Directors and committees on which such director sits, and to review prior to meetings material distributed in advance for such meetings. Thus, the number of other public company boards and other boards (or comparable governing bodies) on which a prospective nominee is a member, as well as his or her other professional responsibilities, will be considered. Also, under our Corporate Governance Guidelines, there are no limits on the number of three-year terms that may be served by a director. However, in connection with evaluating recommendations for nomination for reelection, the Nominating and Corporate Governance Committee considers director tenure. We value diversity on a company-wide basis, but have not adopted a specific policy regarding Board diversity.

Stockholder Recommendations for Nominations to the Board of Directors

The Nominating and Corporate Governance Committee will consider properly submitted stockholder recommendations for candidates for our Board of Directors who meet the minimum qualifications as described above. The Nominating and Corporate Governance Committee does not intend to alter the manner in which it evaluates candidates, including the minimum criteria set forth above, based on whether or not the candidate was recommended by a stockholder. A stockholder of record can nominate a candidate for election to the Board of Directors by complying with the procedures in Article I, Section 1.11 of our Bylaws. Any eligible stockholder who wishes to submit a nomination should review the requirements in the Bylaws on nominations by stockholders. Any nomination should be sent in writing to our Corporate Secretary, Sierra Oncology, Inc., c/o 2150 – 885 West Georgia Street, Vancouver, British Columbia V6C 3E8, Canada.1820 Gateway Drive, Suite 110, San Mateo, CA 94404. Submissions must include the full name of the proposed nominee, complete biographical information, a description of the proposed nominee’s qualifications as a director, other information specified in our Bylaws, and a representation that the

executive offices not later than the close of business on the 75th day nor earlier than the close of business on the 105th day prior to the anniversary of the preceding year’s Annual Meeting, except that if the date of the Annual Meeting is more than 30 days before or more than 60 days after such anniversary date, for the stockholder notice to be timely, it must be delivered to the Corporate Secretary at our principal executive offices not earlier than the close of business on the 105th day prior to the currently proposed Annual Meeting and not later than the close of business on the later of (1) the 75th day prior to such Annual Meeting or (2) the close of business on the 10th day following the day on which public announcement of the date of such meeting is first made by us. Stockholders are also advised to review our Bylaws, which contain additional requirements with respect to advance notice of stockholder proposals and director nominations.

Hedging Prohibitions

Under our Insider Trading Policy, directors and executive officers, as well as other employees, are prohibited from hedging their interest in our shares by selling short or trading or purchasing “put” or “call” options on our securities or engaging in similar transactions.

PROPOSAL NO. 1

ELECTION OF CLASS IIIII DIRECTORS

Our Board of Directors is divided into three classes. Each class serves for three years, with the terms of office of the respective classes expiring in successive years. Directors and director nominees in Class IIIII will stand for election at this meeting. The terms of office of directors in Class IIII and Class III do not expire until the Annual Meetings of Stockholders to be held in 20212022 and 2022,2023, respectively. Our Nominating and Corporate Governance Committee recommended to our Board of Directors, and our Board of Directors nominated Dr. Allen, Dr. AshiyaDilly, Mr. Pelzer and Dr. Sinclair,Richardson, each an incumbent Class IIIII director, for election as Class IIIII directors at the Annual Meeting. At the recommendation of our Nominating and Corporate Governance Committee, our Board of Directors proposes that each of the Class IIIII nominees be elected as a Class IIIII director for a three-year term expiring at the 20232024 Annual Meeting of Stockholders and until such director’s successor is duly elected and qualified or until such director’s earlier resignation or removal.

Each director will be elected by a plurality of the votes present in person or represented by proxy at the meeting and entitled to vote on the election of directors. This means that the three individuals nominated for election to the Board of Directors at the meeting receiving the highest number of “FOR” votes will be elected. You may vote “FOR ALL NOMINEES”, “WITHHOLD AUTHORITY FOR ALL NOMINEES” or vote “FOR ALL EXCEPT” one or more of the nominees you specify. Shares represented by proxies will be voted “FOR” the election of each of the Class IIIII nominees, unless the proxy is marked to withhold authority to so vote. You may not cumulate votes in the election of directors. If any nominee for any reason is unable to serve, the proxies may be voted for such substitute nominee as the proxy holders, who are officers of our company, might determine. Each nominee has consented to being named in this proxy statement and to serve if elected. Proxies may not be voted for more than three directors.

Nominees to the Board of Directors

The nominees and their ages as of DecemberMarch 31, 20192021 are provided in the table below. Additional biographical information for each nominee is set forth in the text below the table.

Andrew Allen, M.D.Stephen G. Dilly, M.B.B.S., PhDPh.D.,. has served as our President and Chief Executive Officer and as a member of our Board of Directors since October 2017.June 2020. Previously, Dr. Allen hasDilly served as Chief Executive Officer of Aimmune Therapeutics, Inc., a biopharmaceutical company, from April 2014 to June 2018 and as a member of Aimmune’s board of directors from April 2013 to June 2018. Dr. Dilly was Chief Executive Officer of PhotoThera, Inc., a medical device company, from January 2012 to December 2012. Dr Dilly currently serves on the board of directors of Codexis Inc and is chairman of the Science and Technology Committee and a member of the Nominating and Governance committee. From 2010 to 2020, Dr. Dilly served as an independent director of Sangamo Biosciences, Inc., where he also served as chair of the clinical review committee. From 2006 to 2011, Dr. Dilly served as President and Chief Executive Officer and a member of the board of directors of APT Pharmaceuticals, Inc. From 2007 to 2009, he was a member of the board of directors of Avigen, Inc., which merged with MediciNova, Inc. in December 2009. From 2003 to 2006, he served as Chief Medical Officer and Senior Vice President of Gritstone Oncology,Development of Chiron BioPharma, which was later acquired by Novartis International AG. From 1998 to 2003, Dr. Dilly held various management positions at Genentech, Inc., including Vice President of Development Sciences from 2002 to 2003 and Vice President of Medical Affairs from 1998 to 2001. From 1988 to 1998, Dr. Dilly held various management positions in drug development with SmithKline

Beecham, PLC, a healthcare company in the U.K.. Dr. Dilly received an immunotherapy companyM.B.B.S. from the University of London in the U.K. and a Ph.D. in cardiac physiology from University of London. Our Board of Directors believes that Dr. Dilly should serve as a director based upon his expertise in the biopharmaceutical industry and the insight and strategy heco-founded, can provide as our Chief Executive Officer.

Robert Pelzer has served as Chairman of our Board of Directors since AugustNovember 2019 and a member of our Board of Directors since May 2015. From April 2009September 2008 to August 2015, Dr. AllenMarch 2013, Mr. Pelzer served as the Executive Vice President of Clinical andPre-Clinical Development and Chief Medical Officer of Clovis Oncology, Inc., a biopharmaceutical company that heco-founded. Prior to cofounding Clovis, he served in the same role at PharmionNovartis Corporation, a pharmaceutical company, beginning in 2006.company. From 20042002 to 2006, Dr. Allen2008, Mr. Pelzer served as General Counsel at Novartis Pharma AG. Prior to 2002, Mr. Pelzer held various positions, including serving as General Counsel and Senior Vice President of BioPharma Development and Head of the Oncology Therapeutic Unit for Chiron Corporation, a biotechnology company. Priorat DuPont Pharmaceuticals from 1998 to that, Dr. Allen served as global project head in Abbott Laboratories’ oncology franchise, and he progressed through positions of increasing responsibility at the management consulting firm McKinsey & Company, with a focus on oncology strategy. Dr. Allen2001. Mr. Pelzer currently serves on the Board of Directors of Gritstone Oncology,Qu Biologics Inc., Revitope Oncology Inc., TCR2 Therapeutics, Inc., and Epizyme, Inc., and previously served on the Board of Directors of Nodality,Aquinox Pharmaceuticals Inc., and of Cell Design Labs,Idenix Pharmaceuticals, Inc. until their acquisition by Gilead Sciences, Inc. in 2017. Dr. Allen qualified in medicine at Oxford UniversityMr. Pelzer received a BComm and earned his Ph.D.an LL.B. from the Imperial CollegeUniversity of Science, Technology and Medicine in London. Dr. Allen also obtained postgraduate internal medicine qualification as a Member of Royal College of Physicians.Alberta. Our Board of Directors believes that Dr. AllenMr. Pelzer should serve as a director based upon his extensive executive, development and scientific experience in the biopharmaceuticalhealthcare industry.

Columbia University, College of Physicians & Surgeons, and his B.S. in Agricultural Economics from Cornell University. Our Board of Directors believes that Dr. Aggarwal should serve as a director based upon his medical backgroundexperience in the biopharmaceutical and venture capital industries.

Andrew Allen, M.D., Ph.D. has served as a member of our Board of Directors since October 2017. Dr. Allen has served as the Chief Executive Officer and President of Gritstone Oncology, Inc., an immunotherapy company that he co-founded, since August 2015. From April 2009 to August 2015, Dr. Allen served as the Executive Vice President of Clinical and Pre-Clinical Development and Chief Medical Officer of Clovis Oncology, Inc., a biopharmaceutical company that he co-founded. Prior to cofounding Clovis, he served in the same role at Pharmion Corporation, a pharmaceutical company, beginning in 2006. From 2004 to 2006, Dr. Allen served as Vice President of BioPharma Development and Head of the Oncology Therapeutic Unit for Chiron Corporation, a biotechnology company. Prior to that, Dr. Allen served as global project head in Abbott Laboratories’ oncology franchise, and he progressed through positions of increasing responsibility at the management consulting firm McKinsey & Company, with a focus on oncology strategy. Dr. Allen currently serves on the Board of Directors of Gritstone Oncology, Inc., Revitope Oncology, Inc., TCR2 Therapeutics, Inc., and Epizyme, Inc., and previously served on the Board of Directors of Nodality, Inc., and Cell Design Labs, Inc. until its acquisition by Gilead Sciences, Inc. in 2017. Dr. Allen qualified in medicine at Oxford University and earned his Ph.D. from the Imperial College of Science, Technology and Medicine in London. Dr. Allen also obtained postgraduate internal medicine qualification as a Member of Royal College of Physicians. Our Board of Directors believes that Dr. Allen should serve as a director based upon his extensive executive, development and scientific experience in the biopharmaceutical industry.

Mona Ashiya Ph.D. has served as a member of our Board of Directors since November 2019. Dr. Ashiya is a Partner at OrbiMed Advisors, LLC, a healthcare focused investment firm where she has been involved with a number of investments in public and private biotech companies since October 2010. Dr. Ashiya received a B.A. from the University of California, Berkeley and her Ph.D. in Cellular, Molecular and Developmental Biology from the University of Pittsburgh. Our Board of Directors believes that Dr. Ashiya should serve as a director based upon her experience in the venture capital industry and her experience as in investor in biotechnology companies.

Craig Collard has served as a member of our Board of Directors since May 2020. Mr. Collard is currently the CEO of Veloxis Pharmaceuticals, Inc., a transplant focused pharmaceutical company, now a subsidiary of Asahi Kasei Corporation after its acquisition of Veloxis Pharmaceuticals, Inc. for $1.3 billion in 2020. Prior to this, he served as the CEO and Chairman of Cornerstone Therapeutics, Inc., a pharmaceutical company he founded in 2004, until February 2014 when the company was purchased by Chiesi Pharmaceuticals, Inc. Before founding Cornerstone, Mr. Collard served as President and CEO of Carolina Pharmaceuticals, Inc., a pharmaceutical company he founded in May 2003. From 1998 to 2003, Mr. Collard served in various commercial roles at Verum Pharmaceuticals, Inc., and DJ Pharma, Inc. Mr. Collard is a member of the Board of Directors of Veloxis Pharmaceuticals, Inc., Opiant Pharmaceutics, Inc. and TerrAscend Corporation. Mr. Collard received a B.S. in Engineering from the Southern College of Technology (now Southern Polytechnic State University) in Marietta, Georgia. Our Board of Directors believes that Mr. Collard should serve as a director based upon his extensive executive, development, and commercial experience in the biopharmaceutical industry.

Jeffrey H. Cooper has served as a member of our Board of Directors since March 2016. Mr. Cooper has served as an independent consultant for life sciences companies since January 2014. Previously, Mr. Cooper served at KaloBios Pharmaceuticals, Inc., a biotechnology company, as a senior advisor from November 2013 until December 2013 and as the Chief Financial Officer from July 2012 until October 2013. Prior to joining KaloBios, Mr. Cooper served in positions of increasing responsibility at BioMarin Pharmaceutical Inc., a pharmaceutical

at Syntex Corporation. Mr. Cooper also previously served on the Board of Directors of Tobira Therapeutics, Inc. until it was acquired by Allergan plc in November 2016. Mr. Cooper received a B.A. from the University of California, Los Angeles and an M.B.A. from Santa Clara University. He is a Certified Public Accountant (inactive status) in the state of California. Our Board of Directors believes that Mr. Cooper should serve as a director based upon his experience as a senior executive in the life sciences industry, as well as his experience and skills relating to financial statement and accounting matters.

Nick Glover, Ph.D. has served as our President and Chief Executive Officer and as a member of our Board of Directors since September 2014, and provided consulting services to us from July 2014 through August 2014. Previously, Dr. Glover served as the President and Chief Executive Officer at YM BioSciences Inc., an oncology drug development company, from November 2010 until it was acquired by Gilead Sciences Inc. in February 2013. Prior to that, Dr. Glover served as the President and Chief Executive Officer of Viventia Bio Inc., a biopharmaceutical company. Dr. Glover also previously served as an investment manager for MDS Capital, a life sciences venture capital firm. Dr. Glover has also served as a consultant in the biotechnology and life sciences industries at various times since 2008. Since June 2013, Dr. Glover has served on the Board of Directors of MEI Pharma, Inc. Dr. Glover holds a B.Sc. (Hons) in chemistry from the University of East Anglia, a M.Sc. in chemistry from the University of British Columbia and aAndrew Sinclair, Ph.D. in chemistry from Simon Fraser University. Our Board of Directors believes that Dr. Glover should serve as a director based upon his depth and expertise in the biopharmaceutical and venture capital industries and his extensive experience developing and managing biopharmaceutical companies.

Robert Pelzer has served as a member of our Board of Directors since May 2015. From SeptemberNovember 2019. Since November 2008, to March 2013, Mr. PelzerDr. Sinclair has served as the President of Novartis Corporation, a pharmaceutical company. From 2002 to 2008, Mr. Pelzer served as General Counsel at Novartis Pharma AG. Prior to 2002, Mr. Pelzer heldin various positions at DuPont, including servingAbingworth LLP, a life sciences investment group, where he currently serves as General Counsela Partner and Senior Vice President at DuPont Pharmaceuticals from 1998 to 2001. Mr. PelzerPortfolio Manager. Dr. Sinclair currently serves on the BoardBoards of Directors of Qu BiologicsSoleno Therapeutics, Inc. and previously served onVerona Pharma plc. Dr. Sinclair is a member of the BoardInstitute of DirectorsChartered Accountants in England and Wales. Dr. Sinclair received a BSc in Microbiology from King’s College London and his Ph.D. in Chemistry and Genetic Engineering at the BBSRC Institute of Aquinox Pharmaceuticals and Idenix Pharmaceuticals, Inc. Mr. Pelzer holds a BCom and an LL.B. from the University of Alberta.Plant Science, Norwich. Our Board of Directors believes that Mr. PelzerDr. Sinclair should serve as a director based upon his extensive experience in the healthcare industry.

Josh Richardson M.D. has served on our Board of Directors since November 2019. Dr. Richardson has served as Managing Director of Longitude Capital since February 2016 where he focuses on investments in biotechnology companies. From September 2014 to February 2016, Dr. Richardson served as a Public Equities Analyst at HealthCor Management where he managed smallbiopharmaceutical andmid-cap biotechnology investments. Dr. Richardson received his B.S. in Biomedical Science from the University of South Florida, and his M.D. from the University of Virginia. Our Board of Directors believes that Dr. Richardson should serve as a director based upon his medical background and his experience in the venture capital industry.industries.

There are no familial relationships among any of our directors and executive officers.

Non-Employee Director Compensation

In May 2017, our Board of Directors approvednon-employee director compensation providing for an annual retainer of $40,000 to eachnon-employee director. Additionally, the Chairman of our Board of Directors receives an additional annual payment of $30,000; the Chairmen of our Audit, Compensation and Nominating and Corporate Governance Committees receive an additional annual payment of $19,500, $15,000 and $10,000, respectively; and the members of our Audit, Compensation and Nominating and Corporate Governance Committees receive an additional annual payment of $8,000, $6,000 and $5,000, respectively.

The following table sets forth the compensation earned by or paid to ournon-employee directors for services provided during the year ended December 31, 2019.2020. Dr. Glover,Dilly, our President and Chief Executive Officer, received no compensation for his service as a director during 2019.2020.

PROPOSAL NO. 2

RATIFICATION OF INDEPENDENT REGISTERED PUBLIC ACCOUNTING FIRM

Our Audit Committee has selected Deloitte & Touche LLP as our principal independent registered public accounting firm to perform the audit of our consolidated financial statements for the fiscal year ending December 31, 2020.2021. Deloitte & Touche LLP audited our financial statements for the fiscal years ended December 31, 20192020 and 2018.2019. We expect that representatives of Deloitte & Touche LLP will be present at the Annual Meeting, will be able to make a statement if they so desire and will be available to respond to appropriate questions.

At the Annual Meeting, the stockholders are being asked to ratify the appointment of Deloitte & Touche LLP as our independent registered public accounting firm for the fiscal year ending December 31, 2020.2021. Our Audit Committee is submitting the selection of Deloitte & Touche LLP to our stockholders because we value our stockholders’ views on our independent registered public accounting firm and as a matter of good corporate governance. If this proposal does not receive the affirmative approval of a majority of the votes cast on the proposal, the Audit Committee would reconsider the appointment. Notwithstanding its selection and even if our stockholders ratify the selection, our Audit Committee, in its discretion, may appoint another independent registered public accounting firm at any time during the year if the Audit Committee believes that such a change would be in our best interests and the interests of our stockholders.

The following table presents fees for professional audit services rendered by Deloitte & Touche LLP for the audit of our annual financial statements for the years ended December 31, 20192020 and 2018.2019.

Principal Accountant Fees and Services

Policy on Audit CommitteePre-Approval of Audit and PermissibleNon-Audit Services of Independent Registered Public Accounting Firm

Our Audit Committee generallypre-approves all audit and permissiblenon-audit services provided by the independent registered public accounting firm. These services may include audit services, audit-related services, tax services and other services.Pre-approval is detailed as to the particular service or category of services and is generally subject to a specific budget. The independent registered public accounting firm and management are

required to periodically report to the Audit Committee regarding the extent of services provided by the

REPORT OF THE AUDIT COMMITTEE

The information contained in the following report of the Audit Committee is not considered to be “soliciting material,” “filed” or incorporated by reference in any past or future filing by us under the Securities Exchange Act of 1934 or the Securities Act of 1933 unless and only to the extent that we specifically incorporate it by reference.

The Audit Committee has reviewed and discussed with our management and Deloitte & Touche LLP our audited consolidated financial statements as of and for the year ended December 31, 2019.2020. The Audit Committee has also discussed with Deloitte & Touche LLP the matters required to be discussed by Auditing Standard No. 16 adopted bythe applicable requirements of the Public Company Accounting Oversight Board (United States) regarding “Communication with Audit Committees.”and the Securities and Exchange Commission.

The Audit Committee has received and reviewed the written disclosures and the letter from Deloitte & Touche LLP required by applicable requirements of the Public Company Accounting Oversight Board regarding the independent accountant’s communications with the Audit Committee concerning independence, and has discussed with Deloitte & Touche LLP its independence.

Based on the review and discussions referred to above, the Audit Committee recommended to our Board of Directors that the audited consolidated financial statements as of and for the year ended December 31, 20192020 be included in our annual report on Form10-K for the year ended December 31, 20192020 for filing with the Securities and Exchange Commission.

Submitted by the Audit Committee

Jeffrey H. Cooper, Chair

Gaurav Aggarwal

Robert Pelzer

PROPOSAL NO. 3

ADVISORY VOTE ON NAMED EXECTUIVE OFFICER COMPENSATION

Our Board of Directors is committed to excellence in governance. As part of this commitment, and as required by Section 14A(a)(1) of the Exchange Act, our Board of Directors is providing our stockholders with an opportunity to cast a non-binding, advisory vote on the compensation of our named executive officers.

As described below under “Executive Compensation” we have developed a compensation program that is designed to attract and retain key executives responsible for our success and motivate management to enhance long-term stockholder value. The executive compensation program is designed to reward short-term and long-term performance and to align the financial interests of executive officers with the interests of the Company’s stockholders. We believe our executive compensation program strikes an appropriate balance between the implementation of responsible, measured compensation practices and the effective provision of incentives for our named executive officers to exert their best efforts for our success.

We are asking for stockholder approval, on an advisory basis, of the compensation of our named executive officers as disclosed in this Proxy Statement, which include the disclosures in the “Executive Compensation” section, the compensation tables and the narrative discussion following the compensation tables in this Proxy Statement. This vote is not intended to address any specific item of compensation, but rather the overall compensation of our named executive officers and the policies and practices described in this Proxy Statement. For the reasons discussed above, our Board of Directors unanimously recommends that our stockholders vote in favor of the following resolution:

“RESOLVED, that the Company’s stockholders hereby approve, on an advisory basis, the compensation of the named executive officers, as disclosed in the Company’s proxy statement for the 2021 Annual Meeting of stockholders pursuant to the compensation disclosure rules of the Securities and Exchange Commission, including the Summary Compensation Table and the other compensation related tables and disclosure.”

As this vote is advisory, it will not be binding upon our Board of Directors or the Compensation Committee and neither our Board of Directors nor the Compensation Committee will be required to take any action as a result of the outcome of this vote. However, the Compensation Committee will carefully consider the outcome of this vote when considering future executive compensation policies and decisions.

OUR BOARD OF DIRECTORS RECOMMENDS THAT YOU VOTE “FOR” APPORVAL OF PROPOSAL NO. 3.

PROPOSAL NO. 4

ADVISORY VOTE ON THE FREQUENCY OF FUTURE STOCKHOLDER ADVISORY VOTES

ON NAMED EXECUTIVE OFFICER COMPENSATION

As part of our Board of Director’s commitment to excellence in corporate governance, and as required by the Section 14A(a)(2) of the Exchange Act, our Board of Directors is providing our stockholders with an opportunity to cast a non-binding advisory vote on how frequently they would like to vote on future advisory resolutions to approve the compensation of our named executive officers.

Consistent with our compensation philosophy, our executive compensation program promotes both short-term and long-term incentives, especially given the long timelines and risks inherent in our business of pharmaceutical research and development.

After careful consideration, our Board of Directors has determined that holding a vote on an advisory resolution to approve the compensation of our named executive officers Every One (1) year is in the best interest of our stockholders. For the reasons below, the Board of Directors believes that, of the three choices, submitting a non-binding, advisory say-on-pay resolution to stockholders every year is the most appropriate choice. We believe that say-on-pay votes should be conducted every year so that stockholders may annually express their views on our executive compensation program and accordingly the Board of Directors recommends that this vote be held every year. It should be noted, however, that stockholders are not voting to approve or disapprove the Board of Director’s recommendation on this matter. The Compensation Committee, which administers our executive compensation program, values the opinions expressed by stockholders in these votes and will continue to consider the outcome of these votes in making its decisions on executive compensation.

For the reasons discussed above, our Board of Directors recommends that stockholders vote to hold the advisory vote on named executive officer compensation Every One (1) year. Stockholders are not voting, however, to approve or disapprove of this particular recommendation. The proxy card provides for four choices and stockholders are entitled to vote on whether the advisory vote on named executive officer compensation should be held every one, two, or three years, or to abstain from voting.

As this vote is advisory, it will not be binding upon our Board of Directors and our Board of Directors may decide that it is in the best interest of our stockholders to hold an advisory vote on named executive officer compensation more or less frequently than the frequency receiving the most votes cast by our stockholders. However, our Board of Directors will carefully consider the outcome of this vote when considering the frequency of future advisory votes on named executive officer compensation.

OUR BOARD OF DIRECTORS RECOMMENDS THAT YOU VOTE FOR HOLDING THE ADVISORY VOTE ON FUTURE NAMED EXECUTIVE OFFICER COMPENSATION “EVERY ONE (1) YEAR.”

SECURITY OWNERSHIP OF CERTAIN BENEFICIAL OWNERS AND MANAGEMENT

The following table sets forth certain information with respect to the beneficial ownership of our common stock as of March 31, 2020,2021, by:

Percentage ownership of our common stock is based on 10,395,73212,349,961 shares of our common stock outstanding on March 31, 2020.2021. We have determined beneficial ownership in accordance with the rules of the SEC, and thus it represents sole or shared voting or investment power with respect to our securities, and the information is not necessarily indicative of beneficial ownership for any other purpose. Unless otherwise indicated below, to our knowledge, the persons and entities named in the table have sole voting and sole investment power with respect to all shares that they beneficially owned, subject to community property laws where applicable. We have deemed all shares of common stock subject to options or other convertible securities held by that person or entity that are currently exercisable or that will become exercisable within 60 days of March 31, 20202021 to be outstanding and to be beneficially owned by the person or entity holding the option for the purpose of computing the percentage ownership of that person or entity but have not treated them as outstanding for the purpose of computing the percentage ownership of any other person or entity. Unless otherwise indicated, the address of each of the individuals and entities named below is c/o Sierra Oncology, Inc., c/o 2150 – 885 West Georgia Street, Vancouver, British Columbia V6C 3E8, Canada.1820 Gateway Drive, Suite 110, San Mateo, CA 94404.

EXECUTIVE OFFICERS

The following table provides information regarding our executive officers as of March 31, 2020:2021:

Nick Glover, Ph.DStephen G. Dilly, M.B.B.S., Ph.D.,., has served as our President and Chief Executive Officer and as a member of our Board of Directors since September 2014, and provided consulting services to us from July 2014 through August 2014.June 2020. Dr. Glover’sDilly’s biographical information is set forth above under the heading “Proposal No. 1 Election of Class IIIII Directors – Continuing Directors.”

Sukhi Jagpal, C.P.A., M.B.A., has served as our Chief Financial Officer since February 2015. Previously, Mr. Jagpal served as the Chief Financial Officer of QLT Inc., a biotechnology company, from July 2012 to February 2015, where he also served as the Senior Director, Finance and Corporate Controller from January 2011 to June 2012. Mr. Jagpal has also held senior finance positions with Pivotal Corporation, 360networks Inc. and KPMG LLP. Mr. Jagpal is a Chartered Professional Accountant, a Chartered Business Valuator and holds an M.B.A. from Cornell University – S.C. Johnson Graduate School of Management and an M.B.A. from Queens University.

Barbara Klencke, M.D., has served as our Chief Development Officer since June 2015. Previously, Dr. Klencke served as the Senior Vice President, Development at Onyx Pharmaceuticals, a biopharmaceutical company and a subsidiary of Amgen Inc., from January 2011 to June 2015, and as the Group Medical Director in Product Development, Oncology at Genentech, Inc., a biotechnology company, from July 2003 to January 2011. Prior to that, Dr. Klencke served as the Medical Director at Chiron Corporation, a biotechnology company later acquired by Novartis International AG, and as an assistant professor of medicine at the University of California, San Francisco Medical Center. Dr. Klencke currently servesserved on the Board of Directors of Lexent Bio.Bio from 2017 until its acquisition by Foundation Medicine in mid-2020. Dr. Klencke holds a B.S. from Indiana University and an M.D. from the University of California, Davis.

Mark Kowalski, M.D., Ph.D., has served as our Chief Medical Officer since January 2017. Previously, Dr. Kowalski served as the Chief Medical Officer and Senior Vice President at Arbutus Biopharma (formerly Tekmira Pharmaceuticals), a biotechnology company, from August 2013 to September 2016. Prior to that, Dr. Kowalski worked at Gilead Sciences, Inc. from February to August 2013 following Gilead’s acquisition of YM BioSciences Inc., at which Dr. Kowalski had been Chief Medical Officer and Vice President of Regulatory Affairs from November 2010. Dr. Kowalski previously held the position of Chief Medical Officer of Viventia Biotech, a privately-held biotechnology company, which sought protection from creditors under the Companies’ Creditors Arrangement Act in April 2008 in Ontario, Canada. Dr. Kowalski holds a B.A. from Rutgers University and an M.D. and Ph.D. from the University of Kansas School of Medicine.

Kevin Norrett, M.B.A., has served as our Chief Business Officer since August 2020. He previously served as Chief Commercial Officer at Angion Biomedica Corp., a clinical stage biopharmaceutical company, since July 2019. Prior to Angion, Mr. Norrett held roles of increasing responsibility at Aimmune Therapeutics, Inc., a biopharmaceutical company, between January 2017 and July 2019, most recently serving as Vice President, Marketing, Market Access & Commercial Operations from May 2019 until July 2019. Prior to that, Mr. Norrett was Vice President of Market Access & Commercial Development at ZS Pharma, Inc., a biopharmaceutical company, from October 2014 until January 2017. Mr. Norrett holds a B.S. in Biological Sciences from the

University of California, Davis, an M.S. in Biochemistry and Molecular Biology from the University of California, Los Angeles and an MBA from the University of California, Berkeley – Walter A. Haas School of Business.

Christina Thomson, M.S., J.D., has served as our General Counsel since July 2020. She served as General Counsel at Athira Pharma, Inc., a pharmaceutical company, from February 2019 to July 2020. Prior to Athira, Ms. Thomson served as the General Counsel and Secretary of the Infectious Disease Research Institute from September 2017 to December 2018. Ms. Thomson has served as the principal attorney and founder of Thomson Law PLLC since July 2013. Prior to this, Ms. Thomson served as the General Counsel and Corporate Secretary of APT Pharmaceuticals, Inc., a pharmaceutical company, from May 2009 to January 2012. Ms. Thomson received her bachelor’s degree in 1994 from the University of Utah, her master’s degree in Biology from the University of Utah and her J.D. from the University of Utah J. Quinney College of Law.

William D. Turner has served as our Chief Regulatory and Technical Operations Officer since August 2020. He previously served as Principal Consultant for BiopharmBridge, LLC since April 2020 and prior to that held roles of increasing responsibility at Aimmune Therapeutics, Inc., a biopharmaceutical company, between January 2016 and April 2020, most recently serving as Senior Vice President of Technical Operations and Regulatory Science from July 2018 until April 2020. From July 2013 to January 2016, Mr. Turner served as Principal Consultant at Turner Regulatory Solutions, LLC. Mr. Turner holds a B.S. in Medical Microbiology with a minor in Chemistry from California State University at Long Beach.

Our executive officers are appointed by, and serve at the discretion of, our Board of Directors. There are no familial relationships among any of our directors or executive officers.

EXECUTIVE COMPENSATION

The following tables and accompanying narrative disclosure set forth information about the compensation provided to certain of our executive officers during the years ended December 31, 20192020 and 2018.2019. These executive officers, who include our principal executive officer effective June 1, 2020, our principal executive officer until May 22, 2020, and the two most highly-compensated executive officers (other than our principal executive officer) who were serving as executive officers at the end of the fiscal year ended December 31, 2019,2020, were:

We refer to these individuals as our “named executive officers.”

Summary Compensation Table for Fiscal Years 2019 and 2020

The following table presents summary information regarding the total compensation for services rendered in all capacities that was earned by our named executive officers during the years ended December 31, 20192020 and 2018.2019. Dr. KowalskiDilly became our President and Chief Executive Officer on June 1, 2020. The salary for Dr. Dilly reflects the portion of the year he served us in the capacity as an officer from the time his employment became effective. Dr. Dilly was not a named executive officer during the year ended December 31, 20182019 and therefore his compensation for such year is not presented in the table below.

2019 Equity Awards

In March 2019, our Compensation Committee, in its discretion, awarded Dr. Glover, Dr. Klencke and Dr. Kowalski stock options to purchase 15,187, 4,999 and 4,999 shares, respectively, of our common stock with an exercise price of $78.40 per share. Twenty-five percent of the options vest on theone-year anniversary of the vesting commencement date, with the remaining 75% vesting in 36 equal monthly installments thereafter.

20192020 Bonuses

In 2019,2020, bonuses for our named executive officers were based on the achievement of certain corporate objectives, including the achievement of clinical development, corporate development, financial and other business milestones.milestones¹. In January 2020,February 2021, our Compensation Committee determined that 95%100% of these corporate objectives were achieved, and therefore awarded each named executive officer 95%100% of their target bonus. For 2019,2020, Dr. Glover’sDilly’s target bonus was equal to 60%50% of his annual base salary pro-rated from his start date of $607,754,June 1, 2020 of $350,000, Dr. Klencke’s target bonus was equal to 40% of her annual base salary of $486,150$500,735 and Dr. Kowalski’s target bonus was equal to 40% of his annual base salary of $432,600.$445,578. Accordingly, Dr. GloverDilly was awarded $346,420,$175,000, Dr. Klencke was awarded $184,737$200,294 and Dr. Kowalski was awarded $164,388.