DEF 14A of Sutro Biopharma, Inc., Apr 22, 2026

DEF 14A of Sutro Biopharma, Inc.

Filed Apr 22, 2026 · FY20250001193125-26-170354

Open on EDGAR

  1. Considerations in Evaluating Director Nominees

    Considerations in Evaluating Director Nominees The Nominating and Governance Committee is responsible for identifying, considering and recommending candidates to the Board of Directors for Board membership. A variety of methods are used to 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 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 shareholders, 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 Governance Committee may from time-to-time review and recommend to the Board of Directors the desired qualifications, expertise and characteristics of director candidates, including such factors as business experience, diversity of viewpoints and experience, 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 Governance Committee considers these factors in 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 Governance Committee considers director tenure. We value diverse viewpoints and experiences on a company-wide basis but have not adopted a specific policy regarding Board diversity.

  2. Stockholder Recommendations for Nominations to the Board of Directors

    Stockholder Recommendations for Nominations to the Board of Directors The Nominating and 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 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 1.12 of our Amended and Restated Bylaws. Any eligible stockholder who wishes to submit a nomination should review the requirements in the Amended and Restated Bylaws on nominations by stockholders. Any nomination should be sent in writing to our Corporate Secretary, Sutro Biopharma, Inc., 111 Oyster Point Boulevard, South San Francisco, California, 94080. 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 regarding the nominee and proposing stockholder as specified in our Amended and Restated Bylaws, and certain representations regarding the nomination. Any such submission must be accompanied by the written consent of the proposed nominee to be named as a nominee and to serve as a director if elected. These candidates are evaluated at meetings of the Nominating and Governance Committee and may be considered at any point during the year. If any materials are provided by a stockholder in connection with the recommendation of a director candidate, such materials are forwarded to the Nominating and Governance Committee. Additional information regarding the process for properly submitting stockholder nominations for candidates for membership on our Board of Directors is set forth below under “Stockholder Proposals to Be Presented at Next Annual Meeting.” In addition to satisfying the foregoing requirements under our Amended and Restated Bylaws, to comply with the universal proxy rules, stockholders who intend to solicit proxies in support of director nominees other than the Company’s nominees for the 2027 Annual Meeting of Shareholders must provide notice that sets forth the information required by Rule 14a-19 under the Exchange Act.

  3. PROPOSAL NO. 1 ELECTION OF CLASS II DIRECTORS

    PROPOSAL NO. 1 ELECTION OF CLASS II 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 II will stand for election at this meeting. The terms of office of directors in Class III and Class I do not expire until the annual meetings of stockholders to be held in 2027 and 2028, respectively. Our Nominating and Governance Committee recommended to our Board of Directors, and our Board of Directors nominated Ms. Chung, Ms. Matsui, and Mr. Panek, each an incumbent Class II director, for election as Class II directors at the Annual Meeting. At the recommendation of our Nominating and Governance Committee, our Board of Directors proposes that each of the Class II nominees be elected as a Class II director for a three-year term expiring at the annual meeting of shareholders to be held in 2029 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 cast by the holders of the shares present in person or represented by proxy at the meeting and entitled to vote on the election of directors (Broker non‑votes and “WITHHOLD” votes have no effect on the outcome.). This means that the three individuals nominated for election to the Board of Directors at the Annual Meeting receiving the highest number of “FOR” votes will be elected. You may either vote “FOR” one, two, or all of the nominees or “WITHHOLD” your vote with respect to one, two, or all of the nominees. A “WITHHOLD” vote will have no effect on the outcome. Shares represented by proxies will be voted “FOR” the election of each of the Class II 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.

  4. Nominees to the Board of Directors

    Nominees to the Board of Directors The nominees and their ages as of March 31, 2026 are provided in the table below. Additional biographical information for each nominee is set forth in the text below the table.

  5. Nominees to the Board of Directors

    | Name | Age | Class | | Jane Chung, R.Ph. | 55 | Class II Director | | Connie Matsui(1) | 72 | Class II Director | | James Panek(1)(2) | 73 | Class II Director |

  6. Nominees to the Board of Directors

    (1) Member of our Nominating and Governance Committee (2) Member of our Science and Technology Committee Jane Chung, R.Ph., has served as our Chief Executive Officer and a member of our Board of Directors since March 2025. From May 2015 to August 2021, Ms. Chung served in several leadership roles at AstraZeneca, including as President and General Manager of AstraZeneca Canada, Vice President of Sales and Marketing of U.S. Immuno-Oncology, and Senior Commercial Business Director. Prior to that, from May 2013 to May 2015, Ms. Chung served as a Regional Sales Director and Director of Sales Productivity and Effectiveness for Onyx Pharmaceuticals Inc. From October 2003 to May 2013, she served in various commercial roles for Genentech, Inc., including as Commercial Operations Manager, Division Manager and Senior Marketing Manager. Ms. Chung served on the Board of Directors of Viracta Therapeutics, Inc. from 2022 to 2024 and serves on non-profit boards in the science, education, and community development arenas. Ms. Chung received a B.S. in Pharmacy from St. John's University and a B.A. in Psychology from Columbia University. We believe that Ms. Chung is qualified to serve on our Board of Directors because of her role as our Chief Executive Officer as well as her prior experience at various roles within Sutro Biopharma and her broad experience in the biotechnology industry. Connie Matsui has served as a member, and Chair, of our Board of Directors since June 2019 and brings over 18 years of general management experience in the biotechnology industry. From 2004 to 2009, Ms. Matsui served in various leadership positions at Biogen Idec, Inc., including as Executive Vice President, Knowledge and Innovation Networks and Executive Committee member. Prior to that, Ms. Matsui served in various leadership positions at IDEC Pharmaceuticals, a predecessor of Biogen Idec, including Senior Vice President; Collaboration Chair for the late-stage development and commercialization of rituximab (tradenames: Rituxan® and MabThera®) in partnership with Roche and Genentech; and Project Leader for Zevalin®, the first radioimmunotherapy approved by the U.S. FDA. Prior to entering the biotechnology industry, Ms. Matsui worked for Wells Fargo Bank in general management, marketing and human resources. Ms. Matsui currently serves on the board of directors of Artelo Biosciences, Inc., and has served on not-for-profit boards at the local, national and global level. Ms. Matsui previously served on the board of directors of Halozyme Therapeutics, Inc. from July 2006 to February 2025. Ms. Matsui received a B.A. and an M.B.A. from Stanford University. We believe that Ms. Matsui is qualified to serve on our Board of Directors because of her wealth of operational and managerial experience, including her extensive knowledge of the biotechnology industry, her service in other public company management teams and boards and her expertise in organizational and operational development. Her operational development experience includes serving as a Collaboration Chair for the late-stage development and commercialization of rituximab in the three-way IDEC Pharmaceuticals, Roche and Genentech collaboration. Her knowledge in these and other areas provide critical insights to our business, particularly as our Board of Directors considers our collaboration strategies through our proprietary XpressCF® and XpressCF+® platforms. James Panek has served as a member of our Board of Directors since January 2020. Since 2011, Mr. Panek has served as an Independent Consultant for various biopharmaceutical companies, and currently serves as Acting COO and Director for CHO Plus, a privately owned biotechnology company. From 2010 to 2011, Mr. Panek served as interim President, Chief Executive Officer and Principal Financial Officer at DiaDexus, Inc. From 2007 to 2010, Mr. Panek served as President, Chief Executive Officer and Principal Financial Officer for VaxGen, Inc., now a subsidiary of DiaDexus, Inc. From 2002 to 2006, Mr. Panek served as Senior and Executive Vice President of VaxGen, Inc., and Co-Chief Executive Officer and Chairman of the Board for Celltrion Inc., then a VaxGen manufacturing joint venture in Inchon, Korea. In his role with Celltrion, Mr. Panek was responsible for the development and FDA licensure of the first large scale biopharmaceutical manufacturing facility in Asia. From 1982 to 2001, Mr. Panek served in various capacities with Genentech, Inc., including Senior Vice President, Product Operations, and Vice President, Manufacturing, Engineering and Facilities, where he led the development of the world’s largest biotechnology manufacturing facility and was responsible for all operations involved in supplying products for preclinical, clinical, and commercial use. Prior to joining Genentech, Mr. Panek spent six years with Eli Lilly in a variety of engineering and development positions. Mr. Panek previously served on the boards of directors of DiaDexus, Inc., VaxGen, Inc. and Celltrion Inc. Mr. Panek received a B.S. and an M.S. in Chemical Engineering from the University of Michigan. We believe that Mr. Panek is qualified to serve on our Board of Directors because of his 30 years of leadership experience in the biopharmaceutical industry. In particular, Mr. Panek has broad and deep extensive manufacturing and process development experience in our industry, including leading the construction, qualification and operation of Genentech’s pioneering large scale commercial manufacturing facility and his deep experience in managing supply chains and ensuring supply of preclinical, clinical and commercial products.

  7. Continuing Directors

    Continuing Directors The directors who are serving for terms that end following the Annual Meeting and their ages as of March 31, 2026 are provided in the table below. Additional biographical information for each nominee is set forth in the text below the table.

  8. Continuing Directors

    | Name | Age | Class | | Heidi Hunter(1)(2) | 67 | Class I Director | | Jon Wigginton, M.D.(1)(3) | 64 | Class I Director | | Michael Dybbs, Ph.D.(1) | 51 | Class I Director | | Joseph M. Lobacki (2)(3) | 67 | Class III Director | | Daniel H. Petree (3)(4) | 70 | Class III Director | | Sukhi Jagpal(2) | 52 | Class III Director |

  9. Continuing Directors

    (1) Member of our Science and Technology Committee (2) Member of our Audit Committee (3) Member of our Compensation Committee (4) Member of our Nominating and Governance Committee Heidi Hunter has served as a member of our Board of Directors since November 2021. Ms. Hunter is the former President of Cardinal Health Specialty Solutions, a specialty healthcare business. Prior to Cardinal Health, Ms. Hunter served as Senior Vice President for UCB (Union Chimique Belge), a multinational biopharmaceutical company with a primary focus on neurology and immunology disorders from September 2015 to September 2020. Ms. Hunter also served as Senior Vice President and General Manager of Boehringer Ingelheim, a pharmaceutical company, from 2011 to 2015. Prior to Boehringer Ingelheim, Ms. Hunter held similar roles in sales and marketing at Ciba-Geigy (today part of Novartis) and Wyeth Pharmaceuticals LLC (today part of Pfizer) where she led their oncology business. Ms. Hunter also serves on the Board of Directors of Vicore Pharma Holding AB, Bavarian Nordic and IO Biotech. Ms. Hunter received a B.A in Economics from University of Michigan and a M.B.A. from University of Chicago - Booth School of Business. We believe that Ms. Hunter is qualified to serve on our Board of Directors because of her extensive experience in building and developing talent and high-performance teams in the pharmaceutical sector with the skills, motivation, and culture to achieve sustainable results. Ms. Hunter’s experience in various senior management positions, including as the former President of Cardinal Health Specialty Solutions, a portfolio of specialty healthcare businesses, strengthens our Board of Directors’ ability to oversee the important human capital management element of our company. Jon Wigginton, M.D., has served as a member of our Board of Directors since November 2020. Dr. Wigginton is a physician and scientist with expertise in cancer immunotherapy drug development. He has over 25 years of experience in clinical oncology, with leadership experience in both academia and industry. Dr. Wigginton currently serves as President, Research and Development at Bright Peak Therapeutics. Most recently, he was Senior Advisor and Chairman of the SAB at Cullinan Oncology, Inc., having served previously as the Chief Medical Officer focused on developing oncology therapeutics, and as an advisor for MPM Capital, a healthcare investment firm from 2020 to 2021. From August 2013 to March 2020, Dr. Wigginton served as Senior Vice President, Clinical Development and Chief Medical Officer for MacroGenics, Inc., a clinical-stage biopharmaceutical company focused on discovering and developing innovative monoclonal antibody-based therapeutics. From 2008 to 2013, Dr. Wigginton served as the Therapeutic Area Head, Immuno-Oncology, Early Clinical Research and Executive Director, Discovery Medicine-Clinical Oncology at Bristol-Myers. From 2006 to 2008, Dr. Wigginton served as the Director of Clinical Oncology at Merck Research Laboratories. During his academic career, Dr. Wigginton has held several positions at the National Cancer Institute Center for Cancer Research, including Head of Investigational Biologics Section, Pediatric Oncology Branch. Dr. Wigginton also served as a member of the Board of Directors of Checkmate Pharmaceuticals from January 2022 through May 2022, when the company was acquired by Regeneron. Dr. Wigginton previously served as President and as a member of the Board of directors of the Society for Immunotherapy of Cancer (non-profit). Dr. Wigginton received an M.D. and B.S. in Biology from the University of Michigan. We believe that Dr. Wigginton is qualified to serve on our Board of Directors because of his years of experience in clinical oncology and immunotherapy drug development. Dr. Wigginton’s significant experience in developing strategies that ultimately resulted in FDA approval of new treatment options offers a valuable perspective to our Board of Directors’ discussions regarding clinical development of new oncology therapeutics. Michael Dybbs, Ph.D., has served as a member of our Board of Directors since July 2018. Dr. Dybbs is currently a partner at Samsara BioCapital, where he has worked since March 2017. Prior to joining Samsara, Dr. Dybbs was a partner at New Leaf Venture Partners, where he worked from May 2009 until September 2016. Before joining New Leaf Venture Partners, L.L.C., Dr. Dybbs was a principal at the Boston Consulting Group. Dr. Dybbs currently serves on the boards of directors of Nkarta Therapeutics (NKTX), Kalaris Therapeutics (KLRS), Spyglass Pharma (SGP), and several private companies. Dr. Dybbs previously served on the boards of directors of Versartis, Inc. and Dimension Therapeutics, Inc. Dr. Dybbs received an A.B. in biochemical sciences from Harvard College and a Ph.D. in molecular biology from University of California, Berkeley, where he was awarded a Howard Hughes Medical Institute fellowship. We believe that Dr. Dybbs is qualified to serve on our Board of Directors because of his financial and strategic expertise as well as his deep understanding of the life sciences sector developed over years of investing and advising companies of all sizes. Our Board of Directors particularly values Dr. Dybbs’s experience in evaluation of and development of messaging strategies for clinical data. Joseph M. Lobacki has served as a member of our Board of Directors since February 2017. From January 2020 to January 2024, Mr. Lobacki served as president and CEO of Artax, a private biopharmaceutical company developing treatments for autoimmune and inflammatory diseases focused on modulating the T-Cell Receptor response to antigen stimulation. Since January 2024, Mr. Lobacki has served in an advisory role at Artax, and as an independent consultant to Biotech companies. Previously, Mr. Lobacki served as Executive Vice President and Chief Commercial Officer for Verastem, Inc., a biopharmaceutical company focused on the development and commercialization of therapies for the treatment of hematologic malignancies. From November 2016 to December 2017, Mr. Lobacki served as Chief Operating Officer for Crestovo, a clinical-stage biopharmaceutical company focused on microbiome therapies. From 2014 to 2016, Mr. Lobacki served as Chief Commercial Officer at Medivation, Inc., a biopharmaceutical company focused on development of novel therapies for the treatment of serious diseases. From 2012 to 2014, Mr. Lobacki also served as General Manager of Oncology and an independent biotechnology consultant at Idera Pharmaceuticals, Inc., a biopharmaceutical company focused on therapies for cancer and rare diseases. Previously, Mr. Lobacki served as Senior Vice-President and Chief Commercial Officer at Micromet, Inc., Senior Vice-President and General Manager of US Transplant and Oncology at Genzyme Corporation and in various other positions at SangStat Medical Corporation, Cell Pathways, Inc., Rhone-Poulenc Rorer and Lederle Laboratories. Mr. Lobacki previously served on the Board of Directors of Celator Pharmaceuticals Inc. Mr. Lobacki received a B.S. in Biology from Boston College and a B.S. in Pharmacy from the Massachusetts College of Pharmacy. We believe that Mr. Lobacki is qualified to serve on our Board of Directors because of his extensive biopharmaceutical managerial and commercial experience, including his positions of Chief Commercial Officer, Chief Operating Officer, Executive Vice President and Chief Executive Officer of biopharma companies. His broad understanding of medical affairs and commercial development due to his experiences contributes an important perspective to our Board of Directors’ discussions regarding commercial strategy, business development and human capital management matters.

  10. Continuing Directors

    Daniel H. Petree, has served as a member of our Board of Directors since August 2009. In April 2012, Mr. Petree co-founded Four Oaks Partners Consulting, LLC, which provided transaction advisory services to small and medium-sized life science companies until 2021 and in 2000, Mr. Petree co-founded P2 Partners, LLC, Four Oaks' predecessor in the same business which operated until 2012. Before co-founding P2 Partners, Mr. Petree served as President and Chief Operating Officer of Axys Pharmaceuticals, Inc., Executive Vice President and Chief Financial Officer of Arris Pharmaceuticals, Incorporated and Vice President of Business Development at TSI Corporation and was a corporate and securities lawyer. Mr. Petree previously served on the boards of directors of Lpath, Inc., Biocept, Inc. and Cypress Bioscience, Inc. along with a number of privately held biotechnology companies. Mr. Petree received an A.B. in History and Political Science from Stanford University and a J.D. from the University of Michigan Law School. We believe that Mr. Petree is qualified to serve on our Board of Directors because of his deep knowledge and expertise in structuring and negotiating pharmaceutical partnering arrangements and strategic transactions. His significant business development and financing expertise, and in particular his experience with asset monetization, provides our Board of Directors with valuable insight into financing and growth strategies for us. Sukhi Jagpal has served as a member of our Board of Directors since August 2024. Mr. Jagpal brings over twenty years of experience across the biotechnology industry. He previously served as the Chief Financial Officer of Sierra Oncology, guiding the company from its initial public offering in 2015 through to the completion of its $1.9 billion acquisition by GSK in 2022. Previously, Mr. Jagpal served as the Chief Financial Officer of QLT Inc., a public biotechnology company focused primarily on ophthalmology in addition to oncology and dermatology, from 2012 to 2015, where he also served as the Senior Director, Finance and Corporate Controller. Prior to joining QLT in 2003, Mr. Jagpal 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 the S.C. Johnson Graduate School of Management, Cornell University. We believe that Mr. Jagpal is qualified to serve on our Board of Directors because his financial and accounting experience in guiding biotechnology companies, and in particular his prior leadership positions in the biotechnology industry, provides valuable insight.

  11. Non-Employee Director Compensation

    Non-Employee Director Compensation Our compensation arrangements for non-employee directors are reviewed periodically by our Compensation Committee and our Board of Directors. In addition, at the Compensation Committee’s direction, FW Cook, the Compensation Committee’s independent compensation consultant, provided a competitive analysis of director compensation levels, practices and design features as compared to the general market as well as to our compensation peer group. The adjustments made in 2025 are noted below. Our non-employee directors receive the following compensation pursuant to a program adopted by our Board of Directors: • Cash Compensation. The program provides an annual cash retainer of $40,000 to each non-employee director. Additionally, the Chair of our Board of Directors receives an additional annual payment of $35,000; the Chair of our Audit, Compensation, Nominating and Governance and Science and Technology Committees receive an additional annual payment of $20,000, $17,000, $10,000 and $10,000 respectively; and the members of our Audit, Compensation, Nominating and Governance and Science and Technology Committees receive an additional annual payment of $10,000, $8,500, $5,000 and $5,000, respectively. The cash compensation is paid quarterly in arrears and pro-rated for partial quarters served. • Equity Compensation. On the date of the 2025 annual meeting of shareholders, each non-employee director who continued to serve on our Board of Directors immediately following the meeting received an annual option grant to acquire 5,000 shares of our common stock, vesting monthly until the earlier of the next annual meeting of shareholders and the one-year anniversary of grant. In March 2026, to maintain a consistent sharing rate following our February 2026 fundraising, our Board of Directors determined that on the date of the 2026 annual meeting of stockholders, each non-employee director then-serving on our board will receive an stock option grant to acquire up to 10,000 shares of our common stock. Each new non-employee director who joins our Board of Directors will receive an initial option grant to acquire up to 10,000 shares of our common stock vesting monthly over three years from the date of joining as well as a pro-rated annual grant, vesting monthly from the date of grant to the following annual meeting of shareholders. Non-employee directors are also reimbursed for reasonable expenses incurred in serving as a director, including travel expenses for attending meetings of our Board of Directors. The following table sets forth the compensation earned by or paid to the non-employee directors who served during 2025 for services provided during the year ended December 31, 2025. Mr. Newell, our former Chief Executive Officer, and Ms. Chung, our current Chief Executive Officer, each received no compensation for his or her service as a director during 2025.

  12. Non-Employee Director Compensation

    | Name | Fees Earned or | Option Awards ($)(1) | Total ($) | | | Paid in Cash ($) | | | | Connie Matsui | $80,000 | $41,795 | $121,795 | | Michael Dybbs, Ph.D. | 45,000 | 41,795 | 86,795 | | John Freund, M.D.(2) | 21,703 | — | 21,703 | | Heidi Hunter | 57,500 | 41,795 | 99,295 | | Joseph Lobacki | 67,000 | 41,795 | 108,795 | | James Panek | 55,000 | 41,795 | 96,795 | | Daniel Petree | 53,500 | 41,795 | 95,295 | | Jon Wigginton, M.D. | 58,500 | 41,795 | 100,295 | | Sukhi Jagpal | 57,500 | 41,795 | 99,295 |

  13. Non-Employee Director Compensation

    (1) The amounts reported in this column represent the aggregate grant date fair value of the stock options granted to our directors during the year ended December 31, 2025 as computed in accordance with Financial Accounting Standards Board Accounting Standards Codification (FASB ASC) Topic 718. The assumptions used in calculating the aggregate grant date fair value of the stock options reported in this column are set forth in Note 13 to our financial statements included in our Annual Report on Form 10-K for the year ended December 31, 2025. The amounts reported in this column reflect the accounting cost for these stock options, and do not correspond to the actual economic value that may be received by our directors from the stock options. For information regarding the number of stock options held by each non-employee director as of December 31, 2025, see the table below. (2) Dr. Freund resigned from our Board of Directors in June 2025. The following table sets forth the number of outstanding equity awards held by the non-employee directors who served during 2025 as of December 31, 2025:

  14. Non-Employee Director Compensation

    | Name | Option Awards | | Connie Matsui | 19,706 | | Michael Dybbs, Ph.D. | 21,163 | | John Freund M.D. | 15,663 | | Heidi Hunter | 17,738 | | Joseph Lobacki | 22,797 | | James Panek | 19,799 | | Daniel Petree | 21,163 | | Jon Wigginton M.D. | 18,599 | | Sukhi Jagpal | 12,895 |

  15. Non-Employee Director Compensation

    OUR BOARD OF DIRECTORS RECOMMENDS A VOTE “FOR” THE ELECTION OF EACH OF THE NOMINATED CLASS II DIRECTORS.

  16. Executive Summary

    Executive Summary We are a clinical stage oncology company developing site-specific and novel-format antibody drug conjugates, or ADCs, enabled by our proprietary integrated cell-free protein synthesis platform, XpressCF®, and our site-specific conjugation platform, XpressCF+®. We aim to design and develop therapeutics using the most relevant and potent modalities, including ADCs, bispecific ADCs, immunostimulatory ADCs, or iADCs, and dual payload ADCs, or dpADCs. Our molecules are directed primarily against clinically validated targets where the current standard of care is suboptimal. We believe that our platform allows us to accelerate the discovery and development of potential first-in-class and/or best-in-class molecules by enabling the rapid and systematic evaluation of protein structure-activity relationships to create optimized homogeneous product candidates. Our mission is to transform the lives of patients by creating medicines with improved therapeutic profiles for areas of unmet need. Our NEO compensation program in 2025 was designed to be aligned with industry practices and align executive compensation with our performance, with an emphasis on long-term equity compensation in the form of stock options and restricted stock units, or RSUs.

  17. Business Highlights

    | Compensation Practices and Governance Highlights | | | Pay for Performance | Significant link between the compensation of our NEOs and the achievement of our short- and long-term business objectives through annual cash incentives that are tied to progression of our proprietary and partnered pipeline products, deal-making, financial performance, manufacturing success, and cultural and compliance priorities and with long-term equity compensation that rewards creation of stockholder value through stock options and RSUs | | Stockholder Alignment | Alignment of the interests of our NEOs with those of our stockholders through the use of long-term equity incentives, the value of which is dependent on our stock price performance | | Compensation Governance | Independent directors on the Compensation Committee Compensation Committee meets regularly in executive session without management present Independent compensation consultant, FW Cook, reports directly to the Compensation Committee Compensation Committee regularly considers risks related to compensation policies and practices | | Change in Control Provisions | Change in control payments contingent upon “double-trigger” No tax gross-ups on severance or change in control benefits | | Post-Termination Retirement Benefits | No post-termination retirement or pension benefits | | Prohibition on Hedging, Margin Loans and Pledging | Prohibit hedging, purchases on margin, and pledging of our common stock by all employees and directors | | Clawback Policy | Maintain a compensation recovery policy |

  18. Compensation Philosophy, Objectives and Development

    Compensation Philosophy, Objectives and Development Our 2025 compensation strategy emphasizes pay for performance by using both performance-based annual cash incentives and long-term equity awards in the form of stock options and RSUs. Stock options are utilized because they only provide value if the stock price increases. RSUs are also used to retain talent, align with long-term value (both increases and reductions), and because RSUs are less dilutive than stock options. Our stock options generally vest monthly over four years; with a one-year cliff vesting associated with a new hire grant, and our RSUs generally vest annually over four years (with 25% vesting annually), to align with long-term value creation as well as our clinical development and commercialization timeline. Consistent with our pay-for-performance philosophy, and the long product development life cycles in the biopharmaceuticals industry, the Compensation Committee links the compensation of our executive officers to performance by emphasizing equity compensation opportunities for long-term performance and cash incentives for near-term goal alignment. Thus, the total compensation provided to our executive officers will vary from year to year and will vary between executive officers based on corporate performance, including performance against annual goals that are pre-established by the Compensation Committee, as well as individual performance. The Compensation Committee’s 2025 compensation decisions reflected, among other things, the level of goal achievement related to the potential for long-term value creation from our platform and clinical, manufacturing and business achievements. The Compensation Committee will continue to consider scientific and business achievements and market capitalization, among the many factors considered, when making compensation decisions. Our NEOs are also provided market-competitive health and welfare benefits, and as described below, they may be entitled to receive additional benefits if certain criteria are met at termination of employment. We will continue to refine the design of our compensation program and implement one that is appropriate for our company given our business, industry, growth, and other factors.

  19. Program Development and Role of Compensation Committee, Compensation Consultant and Management

    Program Development and Role of Compensation Committee, Compensation Consultant and Management Role of Compensation Committee. Our Compensation Committee is responsible for overseeing the total compensation of our executive officers, including the underlying philosophy and related policies. As such, the Compensation Committee designs, implements, reviews and approves all compensation for our CEO and our other executive officers. From time to time, and in conjunction with our Compensation Committee, the independent members of our Board of Directors, including our Chairperson, may also be involved in setting the compensation of our CEO and other executive officers and determining the corporate objectives upon which our short-term incentives are based and assessed. Our Compensation Committee’s decisions and recommendations regarding executive compensation are based on the Compensation Committee’s assessment of the performance of our company and each individual executive officer, as well as other factors, such as prevailing industry trends, retention, and the competitive market for executive talent. The Compensation Committee consults with its independent compensation consultant, legal counsel and other advisors in designing our compensation program, including in evaluating the competitiveness of individual compensation and in relation to our performance goals. The Compensation Committee also considers peer company data and factors such as the past, current and expected contributions of each NEO, our corporate performance and strategic focus, global economic conditions, the mix of compensation that would be most appropriate for each NEO, and such officer’s particular responsibilities, experience, level of accountability and decision authority. Role of CEO and Management. As part of the process for setting the compensation of our NEOs, our Chief Executive Officer provides the Compensation Committee with her performance assessments of the company and of the individual NEOs and recommends to the Compensation Committee base salaries, target annual cash incentives (as a percentage of base salary), annual cash incentive payouts (actual incentive paid based on performance against goals), and stock-based compensation for our NEOs (other than for herself). The Compensation Committee considers our Chief Executive Officer’s input and can accept, reject or modify these recommendations in its discretion. The Compensation Committee meets in executive session without management. Various members of management may attend Committee meetings, and they and other employees, as well as outside advisors or consultants, may be invited by the Compensation Committee to make presentations, provide financial, competitive market, or other background information or advice. None of our NEOs were present during the Compensation Committee’s determinations regarding his or her own compensation. Role of Independent Compensation Consultant & Market Data. The Compensation Committee has retained FW Cook as its compensation consultant. FW Cook reports directly to the Compensation Committee and takes its direction from the Chair of the Compensation Committee, working with management on select issues under the Compensation Committee’s oversight. The Compensation Committee retained FW Cook in 2025 to provide data, context, and advice regarding executive officer compensation and our peer group, and to assist with compensation risk assessments.

  20. Peer Groups Used in Program Development and Compensation Decisions

    Peer Groups Used in Program Development and Compensation Decisions Our Compensation Committee considers peer data as one factor in its overall compensation analysis and for purposes of assessing the competitiveness of the executive compensation program. An individual NEO may earn more or less than the peer group median depending on factors described below under the heading “2025 Compensation Decisions,” including the individual’s experience, role, and past and expected future performance.

  21. Fiscal 2025 Peer Group

    Fiscal 2025 Peer Group In the third quarter of 2024, the Compensation Committee reviewed and updated our peer group to include the group of companies set forth below based on, among other considerations, objective size criteria, including industry, market capitalization, headcount, pipeline, location, scope of operations and commercial stage. We refer to this peer group of 18 companies as the “2025 Peer Group.” When this peer group was approved by the Compensation Committee to inform 2025 compensation, these companies had July 15, 2024 market capitalizations of between $54 million and $1.7 billion, and our $345 million market capitalization on this date was within the peer range.

  22. Fiscal 2025 Peer Group

    | Fiscal 2025 Peer Group | | | | Alector, Inc. | G1 Therapeutics, Inc. | Mersana Therapeutics, Inc. | | Allogene Therapeutics, Inc. | Gossamer Bio, Inc. | Nurix Therapeutics, Inc. | | Anaptys Bio, Inc. | Gritstone Bio, Inc. | Poseida Therapeutics, Inc. | | Arcus Biosciences, Inc. | IGM Biosciences, Inc. | Replimune Group, Inc. | | Atara Biotherapeutics, Inc. | Kura Oncology, Inc. | Sangamo Therapeutics, Inc. | | Caribou Biosciences, Inc. | MacroGenics, Inc. | Zymeworks Inc. |

  23. Fiscal 2025 Peer Group

    Compared to the 2025 Peer Group, the following companies were removed due to acquisition or wind-down of those organizations: Alaunos Therapeutics, Inc., ImmunoGen, Inc., and Jounce Therapeutics, Inc. Two companies that fit the Compensation Committee’s desired criteria and had market capitalization on July 15, 2024 ranging from $192 million to $330 million were added to the 2025 Peer Group: Caribou Biosciences, Inc. and Poseida Therapeutics, Inc.

  24. Compensation Consultant Conflict of Interest Analysis

    Compensation Consultant Conflict of Interest Analysis The Compensation Committee has determined that the work of FW Cook and the individual compensation advisors employed by FW Cook does not create any conflict of interest. In making that determination, the Compensation Committee took into consideration the following factors: (i) the provision of other services to us by FW Cook; (ii) the amount of fees we paid FW Cook as a percentage of FW Cook’s total revenue; (iii) FW Cook’s policies and procedures that are designed to prevent conflicts of interest; (iv) any business or personal relationship of FW Cook or the individual compensation advisors employed by FW Cook with a Sutro executive officer; (v) any business or personal relationship of the individual compensation advisors with any member of the Compensation Committee; and (vi) any Sutro stock owned by FW Cook or the individual compensation advisors employed by the consultant. During 2025, we paid FW Cook fees that constituted less than 1% of FW Cook’s total revenue.

  25. Summary

    Summary Most 2025 compensation decisions were made in the first quarter of 2025 and were significantly influenced by our scientific and business achievements together with the competitive market for experienced talent. Our 2025 compensation decisions were based on a review of individual performance and potential; achievement of the Company’s corporate goals, including advancing our research and clinical pipelines and financial performance; and a market analysis of competitive compensation based on our 2025 peer group. Following are highlights of the 2025 compensation decisions: • The salary of certain of our incumbent NEOs was increased in 2025 to reflect promotions and better align with market levels. • Target bonuses as a percentage of salary were not increased for 2025 (other than in connection with promotion). • Ms. Chung's target bonus opportunity was increased from 50% to 60% of base salary in connection with her promotion to Chief Executive Officer.

  26. Performance-Based Cash Incentives

    Performance-Based Cash Incentives During 2025, all of our NEOs were eligible for annual performance-based cash incentive bonuses, which were designed to reward achievement of certain annual corporate goals that the Company believes will ultimately drive stockholder value. Each performance-based cash incentive bonus opportunity is expressed as a target percentage of annual base salary. Mr. Newell’s and Ms. Chung’s target performance-based cash bonus was 60% of each of their annual base salaries, respectively and Dr. Gerber’s and Mr. Chow’s targets were 40% of each of their annual base salaries, respectively. The incentive target as a % of salary for each of our NEOs either remained the same in 2025 as in 2024 (Mr. Newell and Dr. Gerber), was increased as a result of promotion (Ms. Chung), or was the agreed bonus opportunity upon joining the Company (Mr. Chow) . No amount of incentive award was guaranteed. Each NEO’s incentive award payout was based on the level of achievement of the corporate goals that were established by the Compensation Committee in early 2025, and for NEOs other than our CEO, the participant’s role in such goal achievement and the weighting of the goals. The corporate performance goals for the fiscal year 2025 cash incentive bonus program were determined by the Compensation Committee and included certain developmental, research, financial, and operational milestones, as discussed below. These milestones were selected to drive appreciation of value in the Company, including maintaining timelines for development of the Company’s and the Company’s partners’ clinical and preclinical product candidates, successful conclusion of licensing and/or collaboration transactions, expansion and development of the Company’s manufacturing activities through third-party contract development and manufacturing organizations, maintenance of an appropriate cash position and runway, and maintaining Company culture and employee morale. Each of these goals pertain to confidential company development and business plans, the disclosure of which in any additional granularity would result in competitive harm to the company. The Compensation Committee believed that each of these goals would be challenging to achieve. In early 2026, the Compensation Committee assessed our performance against the 2025 corporate goals, using both quantitative measurement and qualitative evaluation. The Compensation Committee determined that the Company had achieved its corporate goals at an overall level of 115% of target. In particular, the Compensation Committee assigned overachievement with respect to early pipeline progression goals, manufacturing and drug supply goals, financial performance and cultural execution goals. The 2025 corporate goals, the weighting of such goals, and the facts the Compensation Committee considered in determining the achievement of such goals are set forth below. In assessing the 2025 corporate goals, the Compensation Committee considered achievement in the following categories with the target weightings as noted: • Early Pipeline Progression (target weighting 30%) • Manufacturing and Drug Supply (target weighting 15%) • Strategic Business Development (target weighting 25%) • Financial Performance (target weighting 20%) • Commitment to Execution, Culture, Talent and Team (target weighting 10%) The Compensation Committee determined that the Company overachieved its goals with respect to Early Pipeline Progression, focusing on the progress made to bring STRO-004 to the clinic and to advance the Company’s additional preclinical programs. An IND was filed in connection with STRO-004 and clinical development was initiated nearly three months ahead of schedule. In addition, STRO-006 was nominated as a development candidate as planned and STRO-227 achieved both optimized lead and development candidate nomination in 2025; nomination of STRO-006 as development candidate in 2025 achieved a stretch goal for the Company. With respect to the goals relating to Manufacturing and Drug Supply, the Compensation Committee determined that the Company overachieved its goals. In particular, the Compensation Committee recognized successful manufacture of STRO-004 and STRO-006 antibody intermediate in the Company’s internal manufacturing facility prior to initiation of decommissioning activities, the successful establishment of an external manufacturing network, and successful reorganization to improve development resourcing and processes following our strategic pivot in March 2025. In addition, the Compensation Committee determined that our manufacturing obligations for our collaboration partners were fully satisfied, though our agreements with our collaboration partners do not permit us to disclose the milestones achieved in these relationships because of applicable confidentiality obligations. With regard to the Company’s financial performance, the Compensation Committee determined that the Company overachieved its goals. In particular, the Company successfully achieved its goal of ending the year with a cash and investments balance sufficient to fund activities through mid-2028, driven by the efficient winddown of luvelta development and additional efficiencies resulting from the Company’s reorganizations and reductions-in-force in March and September 2025. The Compensation Committee also recognized that the Company’s financial performance in 2025 enabled a successful capital raise in early 2026. The Compensation Committee determined that the Company overachieved its goals with respect to its commitment to execution, culture, talent and team. In particular, the Company executed an efficient strategic transition, supported employees through a difficult change management process resulting from the Company’s strategic reprioritization, and drove organizational nimbleness in support of our new early-stage priorities and programs. The Company also developed and introduced a new standard for behavioral competencies for the employees and built upon and innovated new processes, structures and standards intended to support execution, productivity, and efficiency in advancing clinical programs, scientific platform and business operations. The Company further continued development of its compliance initiatives, focusing primarily on developing policy and procedure to support the Company’s strategic pivot. Based on our achievements during 2025, the Compensation Committee determined an overall goal achievement for the Company in 2025 of 115%. Consistent with its determination for maximum possible goal achievement in 2025, the Compensation Committee further determined that the maximum possible goal achievement for the Company in 2026 should be 150%.

  27. Performance-Based Cash Incentives

    | NEO | Target Award | Actual Award | Actual Award % | | Jane Chung, R.Ph. | $405,000 | $465,750 | 115% | | Hans-Peter Gerber, Ph.D. | 212,015 | 243,818 | 115% | | Gregory Chow | 190,000 | 218,500 | 115% | | William Newell | 426,600 | — | —% |

  28. Sign-on Bonuses

    Sign-on Bonuses From time to time, we provide one-time sign-on bonuses to newly hired executive officers as an inducement to join the Company. In 2025, Mr. Chow received a one-time cash sign-on bonus of $25,000 in connection with his appointment as Chief Financial Officer, which is fully repayable if he voluntarily terminates employment prior to the first anniversary of his start date. Sign-on bonuses are not considered part of an NEO's recurring annual compensation and are not factored into performance-based bonus target calculations.

  29. Equity Compensation

    Equity Compensation General. We believe that equity grants provide our NEOs with the opportunity to share in increases, if any, in the value of our common stock, reinforce a long-term interest in our corporate performance, and directly motivate our NEOs to maximize long-term stockholder value. The potential realized value of certain grants depends on our stock performance and all of our equity grants utilize vesting to encourage our NEOs to continue working for us for the long term. The Compensation Committee determines the size and type of equity awards after evaluating various factors applicable at the time of each such grant in their totality, which has included, among other things: the particular NEO’s role and responsibilities and the Compensation Committee’s view of the officer’s individual performance; the prior equity awards granted to such individual; retentive value of prior awards; our corporate performance; the value of equity grants; comparative peer data provided by its compensation consultant; and dilution to our stockholders. All grants to executive officers require the approval of the Compensation Committee. The 2025 grant values were meaningfully lower than the median of grant value benchmarks from the 2025 Peer Group that were reviewed by the Compensation Committee in late 2024 and early 2025. The 2025 grant values were also 34-58% lower than 2024 grant values for the two individuals who were NEOs for the full duration of both years (Ms. Chung and Dr. Gerber). Furthermore, the Compensation Committee increased the weighting of stock options and decreased the weighting of RSUs in 2025 to better align the executive compensation program with our long-term performance and typical peer group practice, and stock options comprised 59-74% of our 2025 NEO grant values (rather than 50% or less in 2024).

  30. Equity Compensation

    | | Equity Compensation (2025 vs. 2024) | | | | NEO(1) | 2024 Equity Grant Value ($)(2)(3) | 2025 Equity Grant Value ($)(2)(4) | 2025 vs. 2024 % Change | | Jane Chung, R.Ph. | $623,360 | $412,680 | -34% | | Hans-Peter Gerber, Ph.D. | 407,532 | 171,552 | -58% | | Gregory Chow | — | 333,938 | N/A |

  31. Equity Compensation

    Excludes Mr. Newell, who was not provided any equity compensation in 2025. (2) These amounts reflect the grant date fair value of the RSUs and Stock Options computed in accordance with FASB ASC Topic 718, as set forth in the Summary Compensation Table below. (3) 2024 equity grant values were 27% in stock options for Ms. Chung and 50% in stock options for Dr. Gerber. The remainder of their grant value was in RSUs. (4) 2025 equity grant values were 59% in stock options for Ms. Chung, 64% in stock options for Dr. Gerber, and 74% of Mr. Chow. The remainder of their grant value was in RSUs. (5) Includes a new-hire award for 27,500 stock options and 10,000 RSUs granted in June 2025. 2025 Stock Options. The stock options granted to Ms. Chung and Dr. Gerber in 2025 vest equally in monthly installments over four years, while 25% of the shares subject to the stock-option granted to Mr. Chow vest 12 months after the vesting start date and the remaining shares vest equally in monthly installments over the next three years. 2025 Restricted Stock Units. The RSUs granted to our NEOs in 2025 vest equally in annual installments over four years.

  32. Employment Agreements and Severance and Change in Control Benefits

    Employment Agreements and Severance and Change in Control Benefits We entered into written employment agreements with each of our NEOs that set forth the terms of their employment, including initial base salaries and eligibility to earn a bonus, as well as standard confidentiality and invention assignment agreements. Each of our named executive officers is, or in the case of Mr. Newell, was, employed “at will”. These arrangements are further described under the section below titled “Executive Compensation Tables.” Our NEOs are entitled to certain severance and change in control benefits under the terms of our executive severance and change in control plan, or Severance Plan. Below is a summary of potential post-termination compensation for our NEOs. We provide these benefits because the Compensation Committee determined that it was appropriate to provide our NEOs with severance compensation if their employment is terminated under certain circumstances. The Compensation Committee believes that the severance benefits are an important element of the NEOs’ competitive pay packages, that they serve important retention and motivation purposes and that such severance benefits, including generally requiring a release of claims against us as a condition to receiving any severance benefits, are best market practice and are in the best interest of the Company and its stockholders. Severance Benefits On March 17, 2021, we adopted an executive severance and change in control plan, or Severance Plan, for each of our executives with the title of vice president (or equivalent) or above, including all of our NEOs. Under the Severance Plan, if we terminate an executive other than for cause or if the executive resigns for good reason, each as defined in the Severance Plan, the executive will receive: (i) cash severance payments payable in monthly installments equal to 18 months of his or her annual base salary for our Chief Executive Officer, 15 months for our other chief executives (including the non-CEO NEOs and those chief executives with an additional title) and 9 months for our senior vice presidents and vice presidents; (ii) a pro rata portion of his or her bonus based on actual achievement of applicable metrics for the year and payable at the same time as bonuses are paid generally; (iii) payment of COBRA premiums for continued medical coverage for up to 18 months for our Chief Executive Officer, 15 months for our other chief executives and 9 months for our senior vice presidents and vice presidents; and (iv) accelerated vesting on outstanding time-based stock options and restricted stock units that vest within 18 months for our Chief Executive Officer, 15 months for our other chief executives and 9 months for our senior vice presidents and vice presidents (any performance-based equity awards will only be accelerated according to the terms of such awards). In the event an executive’s employment terminates without cause or the executive resigns for good reason and such termination occurs on or within 18 months following a change in control, as defined in the Severance Plan, the executive will receive: (i) cash severance payments equal to 18 months of his or her annual base salary for our Chief Executive Officer, 15 months for our other chief executives and 9 months for our senior vice presidents and vice presidents, payable in a lump sum; (ii) a pro rata portion of his or her target bonus for the year, payable in a lump sum; (iii) cash severance payments equal to his or her target bonus for the year multiplied by 1.5 for our Chief Executive Officer, 1.25 for our other chief executives and 0.75 for our senior vice presidents and vice presidents, payable in a lump sum; (iv) payment of COBRA premiums for continued medical coverage for up to 18 months for our Chief Executive Officer, 15 months for our other chief executives and 9 months for our senior vice presidents and vice presidents; and (v) full accelerated vesting on all outstanding stock options and restricted stock units (any performance-based equity awards will only be accelerated according to the terms of such awards). As a condition to receiving these severance benefits, the executive is required to execute a release of claims agreement in favor of us. The Severance Plan continues in effect for three years and shall automatically renew for successive three-year periods thereafter, unless we give notice of non-renewal prior to such renewal date. Although we have the right to amend or terminate the Severance Plan, we may not do so in any manner that diminishes any benefits being paid to an executive at the time of such amendment or termination.

  33. Tax & Accounting Considerations

    Tax & Accounting Considerations We take into account the tax effects of various forms of compensation and the potential for excise taxes to be imposed on our executive officers. There are various provisions of the Code that we consider in determining compensation, including the following: Section 162(m). Section 162(m) of the Internal Revenue Code generally disallows a tax deduction for compensation in excess of $1 million paid to “covered employees,” which include our current NEOs. As a result, we expect that compensation awarded to our NEOs will not be deductible to the extent it is in excess of the $1 million threshold. In determining the form and amount of compensation for our NEOs, the compensation committee will continue to consider all elements of the cost of such compensation, including Section 162(m). While the compensation committee considers the deductibility of awards as one factor in determining executive compensation, the compensation committee also looks at other factors in making its decisions and retains the flexibility to award compensation that it determines to be consistent with the goals of our executive compensation program even if the awards are not deductible by us for tax purposes. Sections 280G and 4999. Any payment or benefit provided to executive officers in connection with a change-in-control transaction may be subject to an excise tax under Section 4999 of the Code. These payments also may not be eligible for a company tax deduction pursuant to Section 280G of the Code. If any of these payments or benefits are subject to the excise tax, they may be reduced to provide the individual with the best after-tax result. The individual will receive a reduced amount so that the excise tax is not triggered, or the individual will receive the full amount of the payments and benefits and then be liable for any excise tax. We have not agreed and are not otherwise obligated to provide any named executive officer with such a “gross-up” or other reimbursement. We account for stock compensation in accordance with the authoritative guidance set forth in FASB ASC Topic 718, which requires companies to measure and recognize the compensation expense for all share-based awards made to employees and directors over the period during which the award recipient is required to perform services in exchange for the award. We determine both the grant date fair value and the service period based on applicable accounting standards. This calculation is performed for accounting purposes and reported in the compensation tables included in this proxy statement as applicable.

  34. Compensation Policies and Practices as they relate to Risk Management

    Compensation Policies and Practices as they relate to Risk Management The Compensation Committee has reviewed our executive and employee compensation programs and does not believe that our compensation policies and practices encourage undue or inappropriate risk taking or create risks that are reasonably likely to have a material adverse effect on us. The reasons for the Compensation Committee’s determination include the following: • Long-term equity compensation programs are designed to reward executives and other participants for driving sustainable and profitable growth for shareholders. • Equity incentive awards for our executive officers have included different types of equity instruments, which helps to diversify the executive officers’ interests and limit excessive risk taking. • The vesting periods for our time-based equity awards are designed to encourage executives and other participants to focus on sustained stock price appreciation. Our system of internal controls over financial reporting, standards of business conduct, and compliance programs reduce the likelihood of manipulation of our financial performance to enhance payments under our bonus and sales compensation plans. Our Insider Trading Policy prohibits all employees from pledging stock, engaging in short sales, or hedging transactions involving our stock.

  35. Policies and Practices Related to the Grant of Certain Equity Awards

    Policies and Practices Related to the Grant of Certain Equity Awards Our equity awards, including stock options, are granted in connection with our yearly compensation cycle and regularly scheduled meetings of our Compensation Committee. Our Compensation Committee does not grant equity awards in anticipation of the release of material non-public information. Similarly, we do not time the release of material non-public information based on equity award grant dates. During 2025, (i) none of our named executive officers were awarded stock options with an effective grant date during any period beginning four business days before the filing or furnishing of a Form 10-Q, Form 10-K, or Form 8-K that disclosed material non-public information, and ending one business day after the filing or furnishing of such reports, and (ii) we did not time the disclosure of material non-public information for the purpose of affecting the value of executive compensation.

  36. Summary Compensation Table

    Summary Compensation Table 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, 2025 and 2024, as applicable.

  37. Summary Compensation Table

    | Name and Principal Position | Year | Salary($) | Bonus($)(4) | Option Awards($)(1) | Stock Awards($)(1) | Non-Equity Incentive Plan Compensation ($)(2) | All Other Compensation ($) | Total($) | | Jane Chung, R.Ph. | | | | | | | | | | Chief Executive Officer | 2025 | 652,000 | — | 245,280 | 167,400 | 465,750 | 45,500(3) | 1,575,930 | | | 2024 | 560,000 | — | 169,360 | 454,000 | 182,000 | 78,000(3) | 1,443,360 | | William J. Newell | | | | | | | | | | Former Chief Executive Officer | 2025 | 239,693 | — | — | — | — | 1,431,618(5) | 1,671,311 | | | 2024 | 707,500 | — | 589,373 | 758,180 | 277,290 | — | 2,332,343 | | Hans-Peter Gerber, Ph.D. | | | | | | | | | | Chief Scientific Officer | 2025 | 527,532 | — | 110,127 | 61,425 | 243,818 | — | 942,902 | | | 2024 | 512,500 | 100,000 | 203,232 | 204,300 | 133,900 | — | 1,153,932 | | Gregory Chow(6) | | | | | | | | | | Chief Financial Officer | 2025 | 277,083 | 25,000 | 245,938 | 88,000 | 218,500 | — | 854,522 |

  38. Summary Compensation Table

    (1) The amounts reported in the “Option Awards” and “Stock Awards” columns represent the aggregate grant date fair value of such awards granted to our named executive officers during the years ended December 31, 2025 and 2024 as computed in accordance with FASB ASC Topic 718. The assumptions used in calculating the aggregate grant date fair value of the stock options reported in this column are set forth in Note 13 to our financial statements included in our Annual Report on Form 10-K for the year ended December 31, 2025. The amounts reported in these columns reflect the accounting cost for these equity awards, and do not correspond to the actual economic value that may be received by our named executive officers from the equity awards. (2) The amounts reported in this column reflect cash bonuses awarded pursuant to the achievement of our 2025 and 2024 corporate objectives. For more information, see “Executive Compensation-Performance-Based Cash Incentives” included elsewhere in this Proxy Statement. (3) The amounts represent a monthly housing allowance paid to Ms. Chung. (4) The amounts reported in this column represent a one-time sign-on bonus. For more information, see “Executive Compensation-Performance-Based Cash Incentives-Sign-on Bonuses” included elsewhere in this Proxy Statement. (5) As disclosed below in “Offer Letters with NEOs” below, as part of Mr. Newell's transition and separation agreement entered into on March 13, 2025 with the Company, the amount reported represents: (i) two cash payments totaling the gross amount of $1,066,500, equal to 150% of Mr. Newell's annual base salary for 2025; (ii) a lump sum payment of $162,634 reflecting Mr. Newell’s bonus opportunity for the 2025 fiscal year on a pro-rated basis, based on our actual percentage achievement of our 2025 corporate goals; (iii) coverage under the Consolidated Omnibus Budget Reconciliation Act of 1985, as amended paid for by us for up to 18 months beginning June 1, 2025 for a gross amount of $84,782; and (iv) $117,702 corresponding to the incremental value of the post-termination option exercise period extension on Mr. Newell’s stock options, as determined in accordance with FASB ASC Topic 718. Mr. Newell was eligible for the post-termination option exercise period extension, which was extended to employees impacted by the March 2025 reduction-in-force, and the exercise period of his vested stock options with an exercise price of less than $120 was extended for 2 years. (6) Mr. Chow joined the Company on June 2, 2025. The amount disclosed in the Salary column of this Summary Compensation Table reflects his base salary actually paid in 2025.

  39. 2025 Outstanding Equity Awards at Fiscal Year-End Table

    2025 Outstanding Equity Awards at Fiscal Year-End Table The following table presents, for each of our named executive officers, information regarding outstanding stock options and restricted stock units held as of December 31, 2025.

  40. 2025 Outstanding Equity Awards at Fiscal Year-End Table

    | | Option Awards | | | | | Stock Awards | | | | Name | Grant Date | Number of Securities Underlying Unexercised Options (#) Exercisable | Number of Securities Underlying Unexercised Options (#) Unexercisable | Option Exercise Price ($) | Option Expiration Date | Grant Date | Number of Units of Stock That Have Not Vested (#) | Market Value of Units of Stock That Have Not Vested ($) | | William J. Newell | | | | | | | | | | | 3/5/2024(1)(2) | 11,595 | — | 45.40 | 5/1/2027(6) | | | | | | 3/3/2023(1)(2) | 262 | — | 57.90 | 5/1/2027(6) | | | | | | 3/3/2023(1)(2) | 11,194 | — | 57.90 | 5/1/2027(6) | | | | | | 3/4/2022(1)(2) | 1,037 | — | 81.70 | 5/1/2027(6) | | | | | | 3/4/2022(1)(2) | 15,562 | — | 81.70 | 5/1/2027(6) | | | | | | 1/29/2020(1)(2) | 291 | — | 100.90 | 5/1/2027(6) | | | | | | 1/29/2020(1)(2) | 12,208 | — | 100.90 | 5/1/2027(6) | | | | | | 1/29/2019(1)(2) | 927 | — | 104.50 | 5/1/2027(6) | | | | | | 1/29/2019(1)(2) | 43,572 | — | 104.50 | 5/1/2027(6) | | | | | Jane Chung, R.Ph. | | | | | | | | | | | 4/4/2025(1)(2) | — | 20,247 | 5.40 | 4/5/2035 | | | | | | 4/4/2025(1)(2) | 11,624 | 30,128 | 5.40 | 4/5/2035 | | | | | | 3/5/2024(1)(2) | — | 1,562 | 45.40 | 3/5/2034 | | | | | | 3/5/2024(1)(2) | 2,184 | 1,253 | 45.40 | 3/5/2034 | | | | | | 12/1/2023(1)(2) | — | 1,626 | 27.50 | 12/1/2033 | | | | | | 12/1/2023(1)(2) | 1,748 | 126 | 27.50 | 12/1/2033 | | | | | | 3/3/2023(1)(2) | 732 | 1,254 | 57.90 | 3/3/2033 | | | | | | 3/3/2023(1)(2) | 2,013 | — | 57.90 | 3/3/2033 | | | | | | 3/4/2022(1)(2) | 3,937 | 263 | 81.70 | 3/4/2032 | | | | | | 8/9/2021(4)(5) | 16,000 | — | 183.70 | 8/9/2031 | | | | | | | | | | | 4/4/2025(1)(3) | 31,000 | 358,670 | | | | | | | | 3/5/2024(1)(3) | 7,500 | 86,775 | | | | | | | | 12/1/2023(1)(3) | 5,000 | 57,850 | | | | | | | | 3/3/2023(1)(3) | 1,376 | 15,920 | | | | | | | | 3/4/2022(1)(3) | 788 | 9,117 | | Hans-Peter Gerber | | | | | | | | | | | 12/23/2025(1)(2) | — | 6,922 | 10.38 | 12/23/2035 | | | | | | 12/23/2025(1)(2) | — | 1,003 | 10.38 | 12/23/2035 | | | | | | 4/4/2025(1)(2) | 2,296 | 9,954 | 5.40 | 4/4/2035 | | | | | | 3/5/2024(1)(2) | 2,625 | 3,375 | 45.40 | 3/4/2034 | | | | | | 9/18/2023(4)(5) | 9,843 | 7,657 | 37.70 | 9/18/2033 | | | | | | | | | | | 4/4/2025(1)(3) | 11,375 | 131,609 | | | | | | | | 3/5/2024(1)(3) | 3,375 | 39,049 | | | | | | | | 9/18/2023(3)(4) | 7,500 | 86,775 | | Gregory Chow | | | | | | | | | | | 12/23/2025(1)(2) | — | 8,200 | 10.38 | 12/23/2035 | | | | | | 6/16/2025(4)(5) | — | 27,500 | 8.80 | 6/16/2035 | | | | | | | | | | | 6/16/2025(3)(4) | 10,000 | 115,700 |

  41. 2025 Outstanding Equity Awards at Fiscal Year-End Table

    (1) Equity award was granted under our 2018 Equity Incentive Plan. (2) 1/48th of the options vest on each monthly anniversary of the vesting commencement date, subject to the executive’s continued service. 1/4th of the RSUs vest on each annual anniversary of the vesting commencement date, subject to the executive’s continued service. Equity award was granted under our 2021 Equity Inducement Plan. 1/4th of the options vest on the first anniversary of the vesting commencement date and 1/48th of the options vest equally in monthly installments thereafter. The Newell Separation and Transition Agreement extended the post-termination exercise period of Mr. Newell’s outstanding options having an exercise price of less than $120 per share to the earliest of (a) May 1, 2027, (b) the expiration date of the options, (c) the consummation of an Acquisition (as defined in his option agreements) and (d) any earlier date as required by the option agreements.

  42. PAY VERSUS PERFORMANCE

    PAY VERSUS PERFORMANCE In accordance with rules adopted by the Securities and Exchange Commission pursuant to Section 953(a) of the Dodd-Frank Wall Street Reform and Consumer Protection Act of 2010, we provide the following disclosure regarding executive compensation for our principal executive officer (“PEO”) and our other NEOs (“Other NEOs”) and Company performance for the fiscal years listed below. The Compensation Committee did not consider the pay versus performance disclosure below in making its pay decisions for any of the years shown. The amounts shown for Compensation Actually Paid have been calculated in accordance with Item 402(v) of Regulation S-K and do not reflect compensation actually earned, realized, or received by the Company’s NEOs; these amounts reflect the Summary Compensation Table total with certain adjustments as described in the following table and footnotes.

  43. PAY VERSUS PERFORMANCE

    | | SCT Total Comp. for PEO: Ms. Chung(1) | Compensation Actually Paid to PEO: Ms. Chung(2) | SCT Total Comp. for Prior PEO: Mr. Newell(3) | Compensation Actually Paid to Prior PEO: Mr. Newell(2) | Average Summary Compensation Paid to Other NEOs(4) | Average Compensation Actually Paid to Other NEOs(2)(3) | Value of Initial $100 Investment Based On Sutro TSR(5) | Net Income ($M) | | 2025 | $1,575,930 | $1,868,976 | $1,671,311 | $1,138,558 | $898,712 | $895,764 | $14 | $(191) | | 2024 | — | — | 2,332,343 | 925,006 | 1,308,305 | 558,592 | 23 | (227) | | 2023 | — | — | 2,129,979 | (539,427) | 1,981,262 | 1,891,050 | 53 | (107) |

  44. PAY VERSUS PERFORMANCE

    (1) Ms. Chung has served as the Company's CEO since March 13, 2025. Values shown relate to Ms. Chung's service as CEO during fiscal 2025. (2) To calculate Compensation Actually Paid (CAP), amounts were deducted from and added to the applicable SCT total compensation, as displayed in the exhibit below. (3) Mr. Newell served as the Company's CEO from January 12, 2009 to March 13, 2025. Values shown relate to Mr. Newell's service as CEO during fiscal years 2025, 2024, and 2023. (4) The other NEOs in each covered year were as follows: 2025 - Greg Chow, Hanspeter Gerber; 2024 - Edward Albini, Jane Chung; 2023 - Anne Borgman, Hanspeter Gerber Reflects $100 was invested for the period starting December 31, 2022, through the end of the listed year, in the Company. Historical stock performance is not necessarily indicative of future stock performance.

  45. PAY VERSUS PERFORMANCE

    | | | CEO | | | | | 2025 - Chung | 2025 - Newell | | Summary Compensation Table Total | | $1,575,930 | $1,671,311 | | Grant Date Fair Value of Stock and Option Awards in the Covered Year | | -412,680 | — | | Fair Value at Year-End of Unvested Stock and Option Awards Granted in the Covered Year* | | + 834,154 | — | | Fair Value of Stock and Option Awards Granted in the Covered Year that Vested in the Covered Year* | | + 81,587 | — | | Change in Fair Value of Unvested Stock and Option Awards Granted in Prior Years* | | -130,626 | -69,783 | | Change in Fair Value of Stock and Option Awards from Prior Years that Vested in the Covered Year* | | -79,389 | -87,840 | | Change in Fair Value of Stock and Option Awards from Prior Years that were Forfeited in the Covered Year* | | — | -375,130 | | Compensation Actually Paid | = | $1,868,976 | $1,138,558 |

  46. PAY VERSUS PERFORMANCE

    | | | Average of Other NEOs(4) | | | | 2025 | | Summary Compensation Table Total | | $898,712 | | Grant Date Fair Value of Stock and Option Awards in the Covered Year | | -252,745 | | Fair Value at Year-End of Unvested Stock and Option Awards Granted in the Covered Year* | | + 363,412 | | Fair Value of Stock and Option Awards Granted in the Covered Year that Vested in the Covered Year* | | + 8,061 | | Change in Fair Value of Unvested Stock and Option Awards Granted in Prior Years* | | -103,521 | | Change in Fair Value of Stock and Option Awards from Prior Years that Vested in the Covered Year* | | -18,155 | | Compensation Actually Paid | = | $895,764 |

  47. PAY VERSUS PERFORMANCE

    * All stock option valuations included in "Compensation Actually Paid" values were performed using the Black-Scholes option pricing model in a manner generally consistent with the process used to determine stock option grant date fair values under FASB ASC Topic 718 (refer to our annual report for additional detail). All stock award valuations included in "Compensation Actually Paid" values were performed using closing price of the Company's common stock. The relationship between Compensation Actually Paid (CAP) and the financial performance elements reflected in the above Pay versus Performance tables are described in the below charts: