DEF 14A of Editas Medicine, Inc., Apr 16, 2024

DEF 14A of Editas Medicine, Inc.

Filed Apr 16, 2024 · FY20230001650664-24-000025

Open on EDGAR

  1. Director Nominees

    Director Nominees The following table provides summary information regarding our three director nominees. For detailed information about each nominee’s background and areas of expertise, please see “Proposal No. 1—Election of Three Class II Directors.”

  2. Director Nominees

    | | | Director Since | Independent | | | Other Public Company Boards | | Name and Occupation | Age* | | Yes | No | Committee Memberships* | | | Meeta Chatterjee Chief Strategy Officer of Sun Pharmaceutical Industries Ltd. | 69 | 2020 | X | | Audit | 1 | | Andrew Hirsch Chief Executive Officer of C4 Therapeutics, Inc. | 53 | 2017 | X | | Audit Compensation | 1 | | Gilmore O'Neill Chief Executive Officer of Editas Medicine, Inc. | 59 | 2022 | | X | None | 1 |

  3. Director Nominees

    *As of April 16, 2024

  4. PROPOSAL NO. 1—ELECTION OF THREE CLASS II DIRECTORS

    PROPOSAL NO. 1—ELECTION OF THREE CLASS II DIRECTORS As of the date of this Proxy Statement, our Board consists of nine members, including a chair of the Board. In accordance with the terms of our restated certificate of incorporation and our amended and restated by-laws, our board of directors is divided into three classes (Class I, Class II and Class III), with members of each class serving staggered three-year terms. The members of the classes are divided as follows: •the Class I directors are Bernadette Connaughton, Elliott Levy, M.D., and Akshay K. Vaishnaw, M.D., Ph.D., and their terms will expire at the annual meeting of stockholders to be held in 2026; •the Class II directors are Meeta Chatterjee, Ph.D., Andrew Hirsch, and Gilmore O’Neill, M.B., M.M.Sc., and their terms will expire at the Annual Meeting; and •the Class III directors are Jessica Hopfield, Ph.D., Emma Reeve, and David T. Scadden, M.D., and their terms will expire at the annual meeting of stockholders to be held in 2025. Upon the expiration of the term of a class of directors, directors in that class will be eligible to be elected for a new three-year term at the annual meeting of stockholders in the year in which their term expires. Our restated certificate of incorporation and our amended and restated by-laws provide that the authorized number of directors may be changed only by resolution of our Board. Our restated certificate of incorporation and amended and restated by-laws also provide that our directors may be removed only for cause by the affirmative vote of the holders of at least 75% of the votes that all our stockholders would be entitled to cast in an annual election of directors, and that any vacancy on our Board, including a vacancy resulting from an enlargement of our Board, may be filled only by vote of a majority of our directors then in office. Our Board has nominated Dr. Chatterjee, Mr. Hirsch, and Dr. O'Neill for election as Class II directors at the Annual Meeting. Each of the nominees is presently a director, and each has indicated a willingness to continue to serve as director, if elected. If a nominee becomes unable or unwilling to serve, however, the proxies may be voted for substitute nominees selected by our Board. We believe that it is essential that our Board members represent diverse backgrounds and experiences, both personally and professionally. Our amended Corporate Governance Guidelines provide that director candidates should have broad experience and skills in areas important to the operation of our company, as well as diversity of age, gender, race, national origin, ethnicity, sexual orientation, and education. Accordingly, the charter of our Nominating and Corporate Governance Committee states that, in recommending directors, the committee shall seek director candidates that have such broad experience, skills and diversity. Currently, our Board includes four female directors and two directors from ethnic or racial minorities. See “—Board Skills & Experience and Demographic Mix” below for additional information. We believe that the backgrounds and qualifications of our directors, considered as a group, should provide a significant breadth of experience, knowledge, and ability to assist our Board in fulfilling its responsibilities. Our priority in selection of Board members is identification of members who will further the interests of our stockholders, and in this context, we consider a variety of attributes in selecting nominees to our Board, including: •an understanding of, and experience in, the biotechnology and pharmaceutical industries, research and academic organizations and governmental regulatory agencies, and the scientific and legal landscapes in which such entities operate; •an understanding of, and experience in, accounting oversight and governance, finance, and complex business transactions; •leadership experience and significant accomplishments with public companies or other comparable organizations; •the ability to contribute positively to the collaborative culture among our Board members; •long-term reputation for the highest personal and professional integrity; and •demonstrated contribution as a member of other boards of directors, and sufficient time and availability to devote to our affairs. These factors and others are considered useful by our Board and are reviewed in the context of an assessment of the perceived needs of our Board at a particular point in time. Certain individual qualifications and skills of our directors that contribute to our Board’s effectiveness as a whole are described in the following paragraphs.

  5. Nominees for Election as Class II Directors

    Nominees for Election as Class II Directors Biographical information, including principal occupation and business experience during the last five years, for our nominees for election as Class II directors at our Annual Meeting is set forth below.

  6. Nominees for Election as Class II Directors

    | | Meeta Chatterjee, Ph.D. Age: 69 Director since 2020 Independent Director Committees: Audit |

  7. Nominees for Election as Class II Directors

    Dr. Chatterjee joined our Board in December 2020. Dr. Chatterjee has served as Chief Strategy Officer of Sun Pharmaceutical Industries Ltd., a private pharmaceutical company, since August 2023. Prior to this role, she was Senior Vice President of Global Business Development at Legend Biotech Corp., a public biopharmaceutical company, from March 2019 to November 2022. She previously served in increasing roles of responsibility at Merck Research Laboratories, a division of Merck & Co., Inc. (“Merck”), from 2007 to May 2018, including serving in its Business Development and Licensing group as Head of Strategy, Transactions and Operations from March 2017 to May 2018 and as Head of the group’s Office of Business Strategy and Operations from May 2014 to March 2017. Prior to joining Merck, Dr. Chatterjee held leadership roles in Discovery Research and in Licensing at Schering-Plough Research Institute and was Head of R&D Licensing at the time of Schering-Plough Corp.’s merger with Merck. She has served on the board of directors of Werewolf Therapeutics, Inc., a public biopharmaceutical company, since October 2021. Dr. Chatterjee holds a B.A. in Physics from Rutgers University and a Ph.D. in Physiology from Rutgers University. She completed her post-doctoral fellowship in the Department of Physiology at the University of Virginia School of Medicine. Skills and Qualifications: We believe Dr. Chatterjee’s qualifications to sit on our Board include her broad strategic and operational experience in pharmaceutical research and development, licensing and strategic transactions.

  8. Nominees for Election as Class II Directors

    | | Andrew Hirsch Age: 53 Director since 2017 Independent Director Committees: Audit, Compensation |

  9. Nominees for Election as Class II Directors

    Mr. Hirsch has served as a member of our Board since May 2017. Mr. Hirsch has served as a director and as the President of C4 Therapeutics, Inc., a public biopharmaceutical company, since September 2020 and as its Chief Executive Officer since October 2020. From September 2016 to September 2020, Mr. Hirsch served as Chief Financial Officer at Agios Pharmaceuticals, Inc. (“Agios”), a public biotechnology company, as well as head of its corporate development beginning March 2018. He served as President and Chief Executive Officer of BIND Therapeutics, Inc., a biotechnology company (“BIND”), from March 2015 until August 2016. Prior to being named President and Chief Executive Officer at BIND, Mr. Hirsch held several other leadership positions at BIND, including Chief Operating Officer from February 2014 to March 2015, and Chief Financial Officer from July 2012 to March 2015. In May 2016, BIND filed a voluntary petition for bankruptcy under Chapter 11 of the United States Bankruptcy Code with the United States Bankruptcy Court. Prior to joining BIND, Mr. Hirsch was Chief Financial Officer at Avila Therapeutics, Inc., a biotechnology company, from June 2011 until its acquisition by Celgene Corporation, a public biopharmaceutical company, in March 2012. From 2002 to 2011, Mr. Hirsch held roles of increasing responsibility at Biogen Inc., a public biotechnology company (“Biogen”), including vice president of Corporate Strategy and M&A. He holds an M.B.A. from the Tuck School at Dartmouth College and a B.A. in Economics from the University of Pennsylvania. Skills and Qualifications: We believe Mr. Hirsch’s qualifications to sit on our Board include his strong business and financial background and experience as an executive at biopharmaceutical companies.

  10. Nominees for Election as Class II Directors

    | | Gilmore O’Neill, M.B., M.M.Sc. Age: 59 Director since June 2022 President and Chief Executive Officer of Editas Medicine |

  11. Nominees for Election as Class II Directors

    Dr. O’Neill has served as our President and Chief Executive Officer and as a member of our Board since June 2022. Prior to joining Editas, Dr. O’Neill most recently served as Executive Vice President of R&D and Chief Medical Officer of Sarepta Therapeutics, Inc., a biopharmaceutical company, from June 2018 to November 2021. Prior to joining Sarepta, Dr. O’Neill held several leadership roles at Biogen over a 15-year period, most recently serving as Senior Vice President, Late Stage Clinical Development from November 2016 to June 2018. He has served on the board of directors of Unity Biotechnology, Inc., a public biopharmaceutical company, since December 2020, and served on the board of directors of Aptinyx, Inc., a public biopharmaceutical company, from October 2021 through April 2023. Dr. O’Neill is licensed to practice medicine in the state of Massachusetts. He received a Bachelor of Medicine degree from University College Dublin and a Master of Medical Sciences degree from Harvard University. Skills and Qualifications: We believe Dr. O’Neill’s qualifications to sit on our Board include his more than 20 years of experience in genetic medicine, neurobiology, and clinical development, during which he has led several successful clinical programs and achieved marketing approval for several medicines. Our Board recommends voting “FOR” the election of Meeta Chatterjee, Andrew Hirsch and Gilmore O'Neill as Class II directors, for a three-year term ending at the annual meeting of stockholders to be held in 2027. Any properly submitted proxy will be voted in favor of the nominees unless a contrary specification is made in the proxy. The nominees have consented to serve as directors if elected. However, if any nominee is unable to serve or for good cause will not serve as a director, the persons named in the proxy intend to vote in their discretion for one or more substitutes who will be designated by our Board.

  12. Directors Continuing in Office

    Directors Continuing in Office Biographical information, including principal occupation and business experience during the last five years, for our current directors continuing in office after the Annual Meeting is set forth below.

  13. Class III Directors (Term Expires at 2025 Annual Meeting)

    Class III Directors (Term Expires at 2025 Annual Meeting)

  14. Class III Directors (Term Expires at 2025 Annual Meeting)

    | | Jessica Hopfield, Ph.D. Age: 59 Director since 2018 Independent Director Committees: Audit, Nominating and Corporate Governance (Chair), Science and Technology |

  15. Class III Directors (Term Expires at 2025 Annual Meeting)

    Dr. Hopfield joined our Board in February 2018 and served as lead independent director from February 2021 to June 2023. Dr. Hopfield has served on the board of directors of Insulet Corporation, a public medical device company (“Insulet”) since July 2015 and as its lead independent director from August 2016 until January 2019, and on the board of directors of Maravai LifeSciences Holdings, Inc., a public diagnostic and reagent company, since November 2020. She previously served on the board of directors of Radius Health, Inc., a public biopharmaceutical company, from January 2019 until December 2020 and PhenomeX Inc. (formerly Berkeley Lights, Inc.), a public medical device company, from December 2021 until its acquisition in October 2023. Since 2010, Dr. Hopfield has been the principal at J Hopfield Consulting providing guidance and executive coaching to start-up technology firms. From 1995 to 2009, Dr. Hopfield was a Partner of McKinsey & Company in its global pharmaceuticals and medical devices practice where she served clients across pharmaceutical, biotechnology, medical device and consumer industries with a focus on strategy, R&D management, and marketing. Dr. Hopfield also previously held management positions at Merck Sharp & Dohme Corp. in clinical development, outcomes research, and marketing. Dr. Hopfield earned a B.S. from Yale College, an M.B.A. from Harvard Graduate School of Business Administration as a Baker Scholar, and a Ph.D. in Neuroscience/Biochemistry from The Rockefeller University. Dr. Hopfield is directorship certified by the National Association of Corporate Directors. Skills and Qualifications: We believe that Dr. Hopfield’s executive and consulting experience in the healthcare, pharmaceutical, and medical device industries and her public company governance experience qualifies her to serve as a member of our Board.

  16. Class III Directors (Term Expires at 2025 Annual Meeting)

    | | Emma Reeve Age: 63 Director since 2021 Board Chair; Independent Director Committees: Audit (Chair), Nominating and Corporate Governance |

  17. Class III Directors (Term Expires at 2025 Annual Meeting)

    Ms. Reeve joined our Board in September 2021 and has served as Chair since June 2023. Ms. Reeve served as Senior Vice President and Chief Financial Officer of Constellation Pharmaceuticals, Inc., a development-stage oncology company, from October 2017, and as its Treasurer from December 2020, until its acquisition in July 2021, and was its Secretary between December 2017 and September 2018. Prior to joining Constellation, Ms. Reeve served as Corporate Controller of Parexel International (“Parexel”), a life sciences consulting firm and contract research organization, from September 2014 to October 2017 and as interim Chief Financial Officer and corporate controller of Parexel from July 2016 to May 2017. Previously, Ms. Reeve served as Head of Finance and Administration at Novartis Pharma Schweiz, a pharmaceutical company, and as Vice President, Global Head Business Planning and Analysis for Novartis Vaccines and Diagnostics, a division of Novartis. Prior to that, she served as the Chief Financial Officer of Inotek Pharmaceuticals, Inc., and of Aton Pharma, Inc., and in operational and finance roles at Merck Research Laboratories and Bristol Myers Squibb Company. Ms. Reeve has served as a member of the boards of directors of Aadi Bioscience, Inc., a public biopharmaceutical company, since September 2021, and PTC Therapeutics, Inc., a public pharmaceutical company, since December 2018. Ms. Reeve received a B.Sc. in computer science from Imperial College, University of London and is an associate of the Institute of Chartered Accountants in England & Wales. Skills and Qualifications: We believe Ms. Reeve is qualified to serve on our Board due to her significant financial and operational experience as an executive at biopharmaceutical companies.

  18. Class III Directors (Term Expires at 2025 Annual Meeting)

    | | David Scadden, M.D. Age: 71 Director since 2019 Independent Director Committees: Compensation, Science and Technology (Chair) |

  19. Class III Directors (Term Expires at 2025 Annual Meeting)

    Dr. Scadden joined our Board in February 2019. Dr. Scadden is the Gerald and Darlene Jordan Professor of Medicine at Harvard University, a position he has held since 2006. Since 1995, Dr. Scadden has practiced at the Massachusetts General Hospital, where he founded and directs the Center for Regenerative Medicine and directed the Hematologic Malignancies Center of the MGH Cancer Center for 10 years. Dr. Scadden co-founded and co-directs the Harvard Stem Cell Institute and is Chairman emeritus and Professor of the Harvard University Department of Stem Cell and Regenerative Biology. He is a member of the National Academy of Medicine and the American Academy of Arts and Sciences and a Fellow of the American College of Physicians and the American Academy for the Advancement of Science. He is a former member of the Board of External Experts for the National Heart, Lung and Blood Institute, the Board of Scientific Counselors for the National Cancer Institute and Board of Directors of the International Society for Stem Cell Research. Dr. Scadden has served on the board of directors of Agios since May 2017 and previously served on the board of directors of Magenta Therapeutics, Inc., a public biotechnology company where he was a scientific founder, from November 2016 until its acquisition in September 2023. He also serves as a member of the board of directors of private biotechnology companies Lightning Biotherapeutics and Sonata Therapeutics. Dr. Scadden holds a B.A. in English from Bucknell University, an M.D. from Case Western Reserve University and holds honorary degrees, including an A.M. from Harvard Medical School, an Sc.D. from Bucknell University and an M.D. from Lund University in Sweden. Skills and Qualifications: We believe Dr. Scadden is qualified to serve on our Board due to his scientific expertise in the fields of hematology and oncology.

  20. Class I Directors (Term Expires at 2026 Annual Meeting)

    Class I Directors (Term Expires at 2026 Annual Meeting)

  21. Class I Directors (Term Expires at 2026 Annual Meeting)

    | | Bernadette Connaughton Age: 65 Director since 2021 Independent Director Committees: Compensation (Chair), Nominating and Corporate Governance |

  22. Class I Directors (Term Expires at 2026 Annual Meeting)

    Ms. Connaughton has served as a member of our Board since October 2021. Ms. Connaughton was previously employed by Bristol Myers Squibb Company, a multinational pharmaceutical company, in various roles from 1983 to 2017, most recently serving as President Intercontinental, including China, Latin America, Central and Eastern Europe and the Middle East. She has served on the board of directors of Halozyme Therapeutics, Inc., a public biotechnology company, since September 2018 and Zealand Pharma A/S, a public biotechnology company, since April 2019. She previously served on the board of directors of Syneos Health, Inc., a public contract research organization, from November 2019 until September 2023. She also serves on the Board of Trustees of the Boys and Girls Club of Mercer County, New Jersey, and is a mentor for the Healthcare Businesswomen’s Association and Women in Bio Boardroom Ready Program. She received a B.A. from Johns Hopkins University and an M.B.A. from The Wharton School, University of Pennsylvania. Skills and Qualifications: We believe Ms. Connaughton is qualified to serve on our Board due to her more than 30 years of global strategic, commercial and biopharmaceutical industry expertise.

  23. Class I Directors (Term Expires at 2026 Annual Meeting)

    | | Elliott Levy, M.D. Age: 65 Director since April 2023 Independent Director Committees: Audit, Science and Technology |

  24. Class I Directors (Term Expires at 2026 Annual Meeting)

    Dr. Levy has served as a member of our Board since April 2023. Dr. Levy is currently a Venture Partner at 5AM Venture Management, LLC, a venture capital firm, which he joined in April 2022. He was previously employed at Amgen, Inc., a public biopharmaceutical company, where he served as Senior Vice President of Research and Development from June 2020 to May 2021 and as Senior Vice President of Global Development from September 2014 to June 2020. He has served on the boards of directors of Omega Therapeutics, Inc., a public biotechnology company, since March 2021 and NuCana plc, a public biotechnology company, since November 2021, and is a co-founder and former chief executive officer of Intrepid Alliance, an industry-led non-profit consortium whose objective is to accelerate the development of small molecule therapeutics for potential viral pandemic agents. Dr. Levy received a B.A. in History from Yale College and an M.D. from the Yale School of Medicine. Skills and Qualifications: We believe Dr. Levy is qualified to serve on our Board due to his extensive experience in clinical development and regulatory approval of investigational medicines in the biopharmaceutical industry.

  25. Class I Directors (Term Expires at 2026 Annual Meeting)

    | | Akshay Vaishnaw, M.D., Ph.D. Age: 61 Director since 2016 Independent Director Committees: Compensation, Science and Technology |

  26. Class I Directors (Term Expires at 2026 Annual Meeting)

    Dr. Vaishnaw has served as a member of our Board since July 2016. Dr. Vaishnaw currently serves as Chief Innovation Officer of Alnylam Pharmaceuticals, Inc. (“Alnylam”), a public company developing RNA-based therapies, and as a Venture Partner at Atlas Venture, a venture capital firm. Dr. Vaishnaw joined Alnylam in 2006 as Vice President, Clinical Research and has then subsequently served in various research and development roles with increasing responsibility. He became President of Research and Development in March 2018 and served as President of Alnylam from January 2022 until October 2023. Dr. Vaishnaw has served on the board of directors of Scholar Rock, Inc., a public biopharmaceutical company, since May 2019. Dr. Vaishnaw is a Fellow of the Royal College of Physicians, United Kingdom. He received an M.D. from University of Wales College of Medicine and a Ph.D. from the University of London. Skills and Qualifications: We believe Dr. Vaishnaw’s qualifications to sit on our Board include his strong medical background and experience as an executive at biopharmaceutical companies. There are no family relationships between or among any of our directors or executive officers. The principal occupation and employment during the past five years of each of our directors was carried on, in each case except as specifically identified above, with a corporation or organization that is not a parent, subsidiary or other affiliate of us. There is no arrangement or understanding between any of our directors and any other person or persons pursuant to which he or she is to be selected as a director. There are no material legal proceedings to which any of our directors is a party adverse to us or any of our subsidiaries or in which any such person has a material interest adverse to us or any of our subsidiaries.

  27. Executive Officers Who Are Not Directors

    Executive Officers Who Are Not Directors Executive officers are chosen by and serve at the discretion of the Board of Directors. Set forth below are the names and ages of our executive officers as of the date of this Proxy Statement, as well as biographical information for all but Gilmore O’Neill, our President and Chief Executive Officer. For Dr. O’Neill’s biographical information, please see page 12.

  28. Executive Officers Who Are Not Directors

    | | Linda C. Burkly, Ph.D. Age: 67 Executive Vice President and Chief Scientific Officer Joined Editas in July 2023 |

  29. Executive Officers Who Are Not Directors

    Dr. Burkly has served as our Chief Scientific Officer since July 2023. Prior to joining us, Dr. Burkly held positions of increasing responsibility over a 37-year tenure at Biogen, where she most recently served as Vice President and Senior Distinguished Investigator from 2014 to 2022. Dr. Burkly earned a B.S. in biology from Fairfield University and a Ph.D. in immunology from Tufts University Graduate School of Biomedical Science. She completed a postdoctoral fellowship in the laboratory of Richard A. Flavell, Biogen Research Corp.

  30. Executive Officers Who Are Not Directors

    | | Erick Lucera Age: 56 Executive Vice President and Chief Financial Officer Joined Editas in May 2023 |

  31. Executive Officers Who Are Not Directors

    Mr. Lucera has served as our Chief Financial Officer since May 2023. He previously served as Chief Financial Officer of AVEO Pharmaceuticals, Inc., a commercial-stage biopharmaceutical company, from January 2020 until its acquisition by LG Chem, Ltd. in March 2023. From August 2016 to January 2020, Mr. Lucera served as Chief Financial Officer of Valeritas Holdings, Inc. (“Valeritas”), a commercial-stage medical technology company. In February 2020, Valeritas filed a voluntary petition for bankruptcy under Chapter 11 of the United States Bankruptcy Code with the United States Bankruptcy Court. Mr. Lucera has served on the boards of directors of Beyond Air, Inc., a public commercial-stage medical device and biopharmaceutical company, since August 2017 and SAB Biotherapeutics, Inc., a public clinical-stage biopharmaceutical company, since April 2023. He previously served on the board of directors of Bone Biologics Corporation, a public medical device company, from October 2021 until December 2023. Mr. Lucera holds a C.P.H. from Harvard University, an M.S. in finance from Boston College, an MBA from Indiana University, Bloomington, and a B.S. in accounting from the University of Delaware. Mr. Lucera currently holds a CFA designation.

  32. Executive Officers Who Are Not Directors

    | | Baisong Mei, M.D., Ph.D. Age: 60 Executive Vice President and Chief Medical Officer Joined Editas in 2022 |

  33. Executive Officers Who Are Not Directors

    Dr. Mei has served as our Chief Medical Officer since July 2022. Prior to joining us, he served as Senior Global Project Head in Rare Diseases and Rare Blood Disorders at Sanofi S.A., a public pharmaceutical and healthcare company, from January 2017 until July 2022. From April 2010 to January 2017, Dr. Mei was employed by Biogen, most recently serving as Therapeutic Area Head, Hematology. Dr. Mei earned a Ph.D. from The University of Toledo in Ohio and received his medical education at Bengbu Medical College and Wuhan University School of Medicine in China. He held postdoctoral fellowships at the University of California San Francisco and the University of California Berkeley.

  34. Compensation Discussion and Analysis

    | •Annual Performance-based Cash Bonus Program: Since 2021 our annual performance-based cash bonus program has provided for independent weighting of corporate and individual achievement to calculate the bonus payout for our employees, including our named executive officers other than our chief executive officer, whose bonus is based solely on corporate achievement. For our named executive officers, corporate and individual performance is weighted as follows: (i)chief executive officer: 100% based on corporate performance (ii)other named executive officers: 80% based on corporate performance, 20% based on individual performance. In February 2024, the Compensation Committee reviewed our performance against our corporate objectives, as well as each named executive officer’s performance against their individual objectives, where applicable. Following this review, the Compensation Committee recommended, and our Board approved, that our corporate objectives were achieved at 102% of target. Taking into account the achievement of our corporate objectives and review of individual performance, our named executive officers received an average payout under the annual performance-based cash bonus program of 102% of target. | | •PSUs retained as part of 2024 Executive Equity Award Program: In February 2024, our Compensation Committee approved our 2024 executive equity program mix under which for each individual the annual equity-based compensation awarded to our senior officers, including our chief executive officer, was: (i)25% in the form of performance-based restricted stock unit (“PSU”) awards that vest only upon achievement by February 2027 of certain research and development milestones applicable to all senior officers, and a minimum one-year vesting period from each individual’s grant date; (ii)25% in the form of time-based vesting restricted stock unit (“RSU”) awards; and (iii)50% in the form of time-based vesting stock options. |

  35. Compensation Objectives and Philosophy

    | Element of Compensation | Purpose | Features | | Base Salary | Attract, retain and reward talented executives needed to drive our business. | Fixed component of compensation to provide financial stability, based on responsibilities, experience, internal equity, performance and peer company data. | | Annual Performance-based Cash Bonuses | Motivate the achievement of business goals that the Compensation Committee and the Board believe are important to the overall success of the business and will enhance stockholder value over time. | Variable component of compensation tied to the achievement of pre-determined corporate performance goals, and for executive officers other than our chief executive officer, on the achievement of pre-determined individual goals that align with our overall strategic and operational priorities. | | Annual Equity Incentives | Assist in retaining our named executive officers and aligning their interests with those of our stockholders by allowing them to participate in the longer-term success of our company as reflected in the appreciation of our stock price. | Variable component of compensation in the form of stock options and RSUs typically subject to multi-year vesting based on continued service, the value of which is tied to the performance of our common stock price, as well as PSUs earned upon achievement of pre-established performance goals within specified time periods. |

  36. Compensation Objectives and Philosophy

    The Compensation Committee works closely with Pearl Meyer & Partners, LLC (“Pearl Meyer”) throughout the year to ensure that our compensation program remains competitive and within market. One of the services provided by Pearl Meyer to the Compensation Committee is the identification of a market framework (including a peer group of companies) for formal compensation benchmarking purposes. Peer group benchmarking is one of the key factors considered by the Compensation Committee in setting named executive officer compensation levels and making other compensation decisions. While starting base salaries, new hire equity grants and our benefit programs are fixed, merit salary increases, actual cash incentive awards and annual equity grants are based on performance against strategic and operational goals. Commitment to Pay-for-Performance The Compensation Committee believes that the total compensation package provided to our named executive officers, which combines both short- and long-term incentives including equity components that are at-risk, •is competitive without being excessive, •is at an appropriate level to assure the retention and motivation of highly skilled and experienced leadership, •is attractive to any additional talent that might be needed in a rapidly changing competitive landscape, •avoids creating incentives for inappropriate risk-taking by the named executive officers that might be in their own self-interests, but might not necessarily be in the best short- and long-term interests of our stockholders, and •provides the appropriate incentives to our executives to create long-term organizational and stockholder value. In establishing the levels and components of compensation for the named executive officers, including our chief executive officer, the Compensation Committee considers a number of factors, including analyses of compensation of peers and other companies in the biopharmaceutical industry, analyses of reports from Pearl Meyer, the satisfaction of (or failure to satisfy) previously-developed performance measurements for the named executive officers and our company, and the value and size of the total vested and unvested equity grants maintained by the named executive officers. The Compensation Committee retains the authority and flexibility to vary the compensation of any individual named executive officer from the targeted pay framework, based on the unique responsibilities and requirements of his or her position, his or her experience and qualifications, internal parity relative to similar positions within our company, and individual or company performance relative to performance goals and our selected peer group to ensure appropriate pay-for-performance alignment. While we do not have a formal or informal policy for allocating between long-term and short-term compensation, between cash and non-cash compensation or among different forms of non-cash compensation, historically, a majority of the compensation for our named executive officers is long-term compensation, balanced with sufficient short-term incentives to encourage consistently strong performance. As shown in the following charts, our compensation program is highly performance-based, with approximately 73% of our chief executive officer’s and, on average, 70% of our other named executive officers’ target compensation being variable, either because it was subject to performance goals, the fluctuations of our stock price, or both. The charts below illustrate the target 2023 pay mix (excluding benefits) for Gilmore O’Neill, our chief executive officer, and for our other named executive officers. Please see “Executive Compensation—2023 Summary Compensation Table” for amounts actually earned by each of them. ________________________ (1)The grant date fair value for PSUs awarded to our named executive officers in 2023 is based on the probable outcome of the performance conditions as of the grant date. See “Executive Compensation—2023 Summary Compensation Table” for the aggregate grant date fair value for such awards assuming all performance conditions are achieved. (2)For purposes of this chart, Mr. Lucera's and Dr. Burkly’s base salaries have been annualized and their respective annual performance-based cash bonus target reflects the amount for which each would have been eligible if employed for all of 2023.

  37. Executive Compensation Program Best Practices

    | | What We Do | | What We Don’t Do | | ✓ | Maintain and evaluate annually an industry-specific peer group for benchmarking pay | | No employment agreements that guarantee a certain compensation level or employment term | | ✓ | Review annually our compensation strategy to ensure target pay is based on market norms | | No guaranteed annual salary increases or guaranteed bonuses | | ✓ | Balance short-and long-term incentives (through annual cash bonuses and equity awards) | | No single-trigger vesting in connection with a change-in-control for equity awards | | ✓ | Maintain a compensation recovery or “clawback” policy | | No excessive executive perquisites or personal benefits | | ✓ | Set robust executive and non-employee director Stock Ownership Guidelines | | No hedging or pledging or speculative transaction in our securities | | ✓ | Use multiple performance measures to determine incentive payouts, include caps on annual incentive payments | | No re-pricing of equity awards without stockholder approval | | ✓ | Engage independent compensation consultant | | No excise tax gross-ups |

  38. Executive Compensation Process

    Executive Compensation Process Role of our Compensation Committee. The Compensation Committee is responsible for, among other things, reviewing and approving, or recommending for approval by our Board, the compensation of our executive officers and our senior management, including salary, bonus and incentive compensation levels, equity compensation (including awards to induce employment), severance arrangements, change-in-control benefits and other forms of executive officer compensation. A full description of the Compensation Committee’s role and responsibilities is in the Compensation Committee’s charter, which is available on our website. Role of Management. As a part of determining named executive officer performance and compensation, the Compensation Committee receives recommendations from our chief executive officer (except with respect to his or her own compensation and performance). Our chief executive officer’s performance and compensation is approved by our Board based upon the recommendation of the Compensation Committee. The evaluation of each of our named executive officers is based on our overall corporate performance against annual goals that are approved by our Board at the beginning of each year and, except with respect to our chief executive officer whose evaluation is based solely on corporate performance, individual performance against pre-established annual goals, as discussed in more detail below. At the invitation of the Compensation Committee, certain members of our senior management also participate in Compensation Committee meetings to share their perspective and relevant information on topics that the Compensation Committee is discussing. Role of the Compensation Committee’s Independent Compensation Consultant. The Compensation Committee has the sole authority to retain, at our expense, one or more third-party compensation consultants to assist the committee in performing its responsibilities. The Compensation Committee may terminate the services of the consultant if the Compensation Committee deems it appropriate. The Compensation Committee utilized the services of Pearl Meyer to assist it in fulfilling its responsibilities in 2023 and 2024. Pearl Meyer was retained exclusively by the Compensation Committee and has not been retained by management to perform any work for our company other than projects performed at the direction of the Compensation Committee. Pearl Meyer provided analysis and recommendations, where applicable, regarding: •trends and emerging topics with respect to executive compensation; •peer group selection for executive compensation benchmarking; •compensation practices of the selected peer group; •compensation philosophy and programs, including risk assessment, for executives; and •stock utilization and other relevant metrics. Pearl Meyer advised the Compensation Committee on all the principal aspects of executive compensation, including executive new hire compensation arrangements. Pearl Meyer consultants attended meetings of the Compensation Committee, including executive sessions in which executive compensation issues are discussed, when requested to do so. Pearl Meyer reported to the Compensation Committee and not to management, although it met with management for purposes of gathering information for its analyses and recommendations. The Compensation Committee annually evaluates its engagement of compensation consultants, and selected Pearl Meyer to advise with respect to compensation matters based on Pearl Meyer’s industry experience and reputation, which the Compensation Committee concluded gave Pearl Meyer useful context and knowledge to advise it. The Compensation Committee has assessed the independence of Pearl Meyer pursuant to SEC and Nasdaq rules and concluded that no conflict of interest exists that would prevent Pearl Meyer from independently advising the Compensation Committee. Defining and Comparing Compensation Benchmarks. The Compensation Committee benchmarks our executive compensation against a peer group of companies to determine competitiveness and market trends. The Compensation Committee reviews the companies in our peer group annually, reviews Pearl Meyer’s recommendations regarding which companies should be included in the peer group and makes adjustments as necessary to ensure the peer group continues to properly reflect the market in which we compete for talented executives. The Compensation Committee also annually reviews the executive pay practices of other similarly situated companies as reported by Pearl Meyer through industry surveys and proxy analysis. These surveys are specific to the biopharmaceutical and biotechnology sector. The Compensation Committee requests customized reports of these surveys so that the compensation data reflect the practices of companies that are like us. The Compensation Committee considers this information when making determinations or recommendations for each element of compensation for our named executive officers. In developing the peer group of companies to inform 2023 compensation decisions, our Compensation Committee, with the assistance of Pearl Meyer, established a peer group of 19 publicly traded, national and regional companies in the biopharmaceutical industry that was selected based on two categories of companies: •clinical stage gene editing, gene therapy, cell therapy or rare/genetic disease companies; and •Massachusetts-based biotechnology or biopharmaceutical clinical stage companies that we believe we compete with for executive talent. Based on these criteria, our peer group for 2023 was comprised of the following companies:

  39. Executive Compensation Process

    Eighteen of the 19 peer companies were determined to be clinical stage companies focused in the gene editing, gene therapy, cell therapy or rare/genetic disease space. The Compensation Committee also added Verve Therapeutics, Inc., a pre-clinical stage company, for being a locally-based, publicly traded company with a similar focus to us and with which we believe we compete for executive talent. The peer group was reviewed for reasonableness based on the following aggregate size statistics:

  40. Executive Compensation Process

    (1)Such amounts were based on publicly available data as of August 26, 2022. (2)Research and development expenses represent such expenses for the most recent four quarters of available public data as of June 30, 2022. (3)Most recently available public data as of June 2022. In evaluating the compensation of our named executive officers for 2023, Pearl Meyer also compared the compensation of select named executive officers to a broader biotechnology industry group, with a focus on public biopharmaceutical companies that were of an equivalent size as our company. The Compensation Committee believed the compensation practices of our peer group provide us with appropriate compensation benchmarks for evaluating the compensation of our named executive officers. Notwithstanding the similarities of the peer group to our company, due to the nature of our business, we compete for executive talent with many companies that are larger and more established than we are or that possess greater resources than we do, as well as with prestigious academic and non-profit institutions. Other considerations, including market factors, the experience level of the executive and the executive’s performance against established corporate goals and individual objectives, may require the Compensation Committee to vary from its historic compensation practices or deviate from its general compensation philosophy under certain circumstances. For the purposes of informing 2024 compensation decisions, the Compensation Committee, with the advice of Pearl Meyer, examined our peer group list using the criteria listed above for 2023. Using these criteria, the Compensation Committee, with the advice of Pearl Meyer, approved the following 20 companies as our 2024 peer group:

  41. Executive Compensation Process

    ________________________ *Addition to 2024 peer group. In determining the 2024 peer group as compared to the 2023 peer group, the Compensation Committee removed Arrowhead Pharmaceuticals, Inc., Denali Therapeutics Inc. and Kodiak Sciences Inc. due to each of their market capitalizations now being outside of our desired range, and Mirati Therapeutics, Inc. and uniQure N.V. due to each of these companies achieving the commercialization stage of development. The Compensation Committee added to our 2024 peer group AlloVir, Inc. and bluebird bio, Inc. for being clinical stage companies that are both locally-based and having a similar focus to us, and Arcturus Therapeutics Holdings Inc., Lyell Immunopharma, Inc., Sana Biotechnology, Inc. and Tenaya Therapeutics, Inc. for being clinical stage companies with a similar focus to us. The 2024 peer group size statistics presented to the Compensation Committee as part of its evaluation were as follows:

  42. Executive Compensation Elements & Decisions

    (1)Base salary increases were prorated to reflect the periods of time that Drs. O’Neill and Mei served as our chief executive officer and chief medical officer, respectively, during 2022. Annual Performance-based Cash Bonus. We have designed our annual performance-based cash bonus program, which is generally guided by specified annual corporate and individual goals and contributions, to emphasize pay-for-performance and reward our named executive officers for overall corporate performance and their individual performance during the preceding year. Under the program, corporate and individual achievement are independently weighted to determine a fixed percent of the bonus payable. The annual performance-based cash bonus for our chief executive officer has historically been, and continues to be, entirely based on the achievement of corporate goals and his or her target bonus amount, but the cash bonus payable to our other executive officers is based 80% on corporate achievement and 20% on individual achievement. As a result, Dr. O’Neill was eligible to receive an annual performance-based cash bonus entirely based on the achievement of corporate goals and his target bonus amount. Our Compensation Committee has the discretion to adjust upward or downward any cash incentive award as it deems appropriate, provided that for the 2023 annual performance-based cash bonus company performance could not exceed 145% and individual performance could not exceed 130% of the applicable pre-defined goals and objectives. This resulted in a maximum payout opportunity in 2023 of 145% of target for our chief executive officer and 142% of target for our other named executive officers. In constructing the goals, the Compensation Committee determined that achieving 100% of target would be sufficiently challenging, and that achieving all of the corporate objectives set out for 2023, equating to 145% of target, would be very challenging and represent a significant achievement for our company. The following formula illustrates the 2023 annual performance-based cash bonus determination for our executive officers, other than our chief executive officer.

  43. Executive Compensation Elements & Decisions

    | Component Calculation | | | | | | | | Company Performance Component | 80% WeightingX | Base SalaryX | Target Bonus PercentageX | Corporate Goal Achievement Percentage (0-145%) | = | Company Performance Component | | Individual Performance Component | 20% WeightingX | Base SalaryX | Target Bonus PercentageX | Individual Goal Achievement Percentage (0-130%) | = | Individual Performance Component | | | | | | | | Total Annual Bonus Payout |

  44. Executive Compensation Elements & Decisions

    | Name | 2023 Target Bonus Percentage | | Gilmore O’Neill | 60% | | Erick Lucera | 45% | | Linda C. Burkly | 45% | | Baisong Mei | 40% | | Michelle Robertson | 45% | | Bruce Eaton | 45% |

  45. Assessment

    | Name | Target Bonus Amount($) | Company Performance Component($) | Individual Performance Component($) | Total Annual Performance- based Cash Bonus Earned($) | | Gilmore O’Neill | 384,840 | 392,537 | N/A(1) | 392,537 | | Erick Lucera | 141,000(2) | 115,056 | 31,020 | 146,076 | | Linda C. Burkly | 111,375(2) | 90,882 | 22,275 | 113,157 | | Baisong Mei | 184,050 | 150,185 | 36,810 | 186,995 | | Michelle Robertson(3) | 211,613 | N/A | N/A | N/A | | Bruce Eaton | 211,307 | 172,426 | 42,262 | 214,688 |

  46. Assessment

    (1)As discussed above, the 2023 performance-based cash bonus for Dr. O’Neill was determined solely based on his 2023 target bonus amount multiplied by the percentage of achievement of our corporate goals, as determined by our Board, and pursuant to the terms of his offer letter. (2)Such amounts have been prorated to reflect the periods of time that Mr. Lucera and Dr. Burkly served as our chief financial officer and chief scientific officer, respectively, during 2023 pursuant to the terms of their offer letters. (3)Ms. Robertson was not eligible to receive a performance-based cash bonus for 2023 due to her separation from our company in August 2023. Equity Incentive Awards. Our equity award program is the primary long-term incentive vehicle for our executives. We believe that equity grants provide our named executive officers with a strong link to our long-term performance, create an ownership culture and help to align the interests of our executives and our stockholders. In addition, the vesting feature of our equity grants contributes to executive retention by providing an incentive to our executives to remain employed by us during the vesting period. None of our named executive officers are currently party to an employment agreement that provides for automatic grants of equity incentive awards. Equity compensation represents the largest at-risk component of our named executive officers’ compensation arrangements. The Compensation Committee periodically reviews our equity compensation strategy to determine the appropriate mix of the type of equity awards, based in part on recommendations from Pearl Meyer, and approves, or, with respect to the chief executive officer, recommends to our Board the annual equity awards to be made to our named executive officers. We currently use time-based stock options, time-based RSUs, and PSUs to compensate our named executive officers in the form of initial grants in connection with the commencement of employment and on an annual basis thereafter. The value that our named executive officers will realize with respect to the grants of time-based stock options and RSUs is tied to our performance, since the value is directly related to our stock price. Stock options will only have value if the value of our common stock appreciates after grant. The RSUs focus on stock appreciation over a sustained period while managing the natural market volatilities of a clinical-stage company. These awards provide retention value by vesting over a multiyear period. Beginning in 2021, we introduced PSUs, which are earned contingent upon the achievement of pre-established performance goals as part of our long-term incentive strategy. For the 2023 annual equity grants, the Compensation Committee approved a target mix of equity awards for our named executive officers consisting of 50% in stock options with time-based vesting, 25% in RSUs with time-based vesting, and 25% in PSUs. The number of shares with respect to each equity award type was based on a target aggregate award amount determined in February 2023 at the time of grant. Mr. Lucera and Dr. Burkly did not participate in the 2023 annual equity award process as neither was an employee at the February 2023 grant date, but they received equity awards in connection with their hire as chief financial officer and chief scientific officer, respectively. Please see “—Compensation of Our Chief Financial Officer and Chief Scientific Officer” for additional information. The Compensation Committee believes that this equity mix helps to ensure executive and stockholder interests are aligned (through stock options) and promotes retention (through RSUs that vest over time), while furthering the development of our pipeline and other related business and market-based objectives (through PSUs that vest only upon the achievement of pre-established operational performance goals). Typically, the stock options that we grant to our named executive officers with time-based vesting become exercisable as to 1/48th of the shares underlying the option monthly beginning after the date of grant, which generally occurs in the first quarter of the calendar year. The exercise price of all stock options equals the fair market value of shares of our common stock on the date of grant. Prior to the exercise of an option, the holder has no rights as a stockholder with respect to the shares subject to such option, including no voting rights and no right to receive dividends or dividend equivalents. Generally, vesting for stock options ceases after termination of employment, and, unless otherwise specified in an employment offer letter or the terms of a specific grant, vested stock options may be exercised up to three months following termination of employment except in the case of death or disability. The RSUs we grant to our named executive officers as part of the annual equity grant vest as to 25% of the shares underlying the RSU on the first anniversary of the grant date, and in equal quarterly installments thereafter, until the fourth anniversary of the grant date. The PSUs we granted in 2023 to our named executive officers vest as to one-third of the shares only upon achievement of three specified research and development and business development milestones on or prior to the third anniversary of the initial February 2023 grant date, but in no event earlier than the one-year anniversary of the applicable officer’s grant date. In specified termination and change in control circumstances, equity awards held by our named executive officers are subject to accelerated vesting. See “—Other Benefits—Severance and Change in Control Benefits” below for further information. In determining the size of the annual equity awards to our named executive officers, the Compensation Committee, with the assistance of Pearl Meyer, considers our company performance, individual performance, the potential for enhancing the creation of value for our stockholders, the retention value of unvested and total equity holdings for each named executive officer, the amount of equity previously awarded to the named executive officers and the vesting terms of such prior awards, our broader organizational equity needs and overall dilution, industry and peer group benchmark data, and, in the case of those officers who joined the company in the prior year, the date of hire. For benchmarking purposes, in 2021 and 2022, our annual equity awards were sized using the grant date fair value of the awards compared to our peer group and survey data compiled by Pearl Meyer in order to align with comparable market practice, emphasize the value of the equity grants being awarded, and better enable a review of total compensation competitiveness. In the 2021 and 2022 compensation planning cycles, the Compensation Committee reviewed the equity awards as a percentage of our shares of common stock outstanding as a secondary measure of the market information. As part of its compensation decisions in early 2023, our Compensation Committee determined that the number of shares with respect to each equity award type would be based on a percentage of common shares outstanding compared to our peer group in order to prevent excessive share usage in light of our stock price at the time of approval. The table below shows all 2023 annual equity grants to those named executive officers who were eligible to receive them.

  47. Assessment

    | Name | 2023 Stock Option Awards(1) | 2023 RSUs(2) | 2023 PSUs(3) | | Gilmore O’Neill(4) | 150,000 | 50,000 | 85,000 | | Baisong Mei(4) | 54,000 | 18,000 | 36,000 | | Michelle Robertson | 94,500 | 31,500 | 31,500 | | Bruce Eaton | 50,000 | 16,700 | 16,700 |

  48. Assessment

    (1)These stock option awards were granted on March 2, 2023 and vest over four years in equal monthly installments beginning on April 2, 2023 through March 2, 2027 and have an exercise price of $8.72 per share. Pursuant to their separation agreements, Ms. Robertson and Dr. Eaton have 12 months following their respective August 2023 and January 2024 separation dates to exercise their outstanding stock options that had vested as of such dates. (2)These RSUs were granted on March 2, 2023 and vest over four years with 25% of the units having vested on March 2, 2024 and the remaining 75% of the units scheduled to vest in quarterly installments thereafter through March 2, 2027. Ms. Robertson’s and Dr. Eaton’s unvested RSUs were forfeited upon their departure from our company in August 2023 and January 2024, respectively. (3)These PSUs were granted on March 2, 2023 and vest on the achievement of specified research and development and business development milestones on or prior to March 2, 2026, provided no shares subject to these PSUs may vest prior to the one-year anniversary of the grant date. The PSUs granted to Ms. Robertson were forfeited upon her departure from our company in August 2023. Pursuant to Dr. Eaton’s separation agreement, any PSUs unearned as of his separation date remained outstanding following his separation on January 2, 2024 and were eligible to vest to the extent that the applicable performance metrics are determined by the Board or the Compensation Committee to have been achieved on or prior to March 31, 2024, provided that such achievement is certified by the Board or the Compensation Committee no later than April 30, 2024. (4)Drs. O’Neill and Mei, whose employment with us commenced in June 2022 and July 2022, respectively, received a pro-rated portion of the grant date fair value of their option awards and RSUs, but the full value for their PSUs. We made equity grants to Mr. Lucera in connection with his hire as our chief financial officer and to Dr. Burkly in connection with her hire as our chief scientific officer. The table below shows the equity grants to Mr. Lucera and Dr. Burkly:

  49. Assessment

    | Name | 2023 Stock Option Awards | 2023 RSUs | 2023 PSUs | | Erick Lucera(1) | 155,800 | 77,900 | 77,900 | | Linda C. Burkly(2) | 135,500 | 45,167 | 45,167 |

  50. Assessment

    (1)In connection with Mr. Lucera’s commencement of employment in May 2023, he was granted on May 17, 2023 (i) a stock option award to purchase 155,800 shares of our common stock, which vests as to 25% of the shares underlying the option on May 17, 2024 and an additional 2.0833% of the shares underlying the option at the end of each successive month following such date until May 17, 2027 and which has an exercise price of $9.61 per share, (ii) an RSU for 77,900 shares of our common stock which vests as to 25% of the shares on each anniversary of the grant date through 2027, and (iii) a PSU for 77,900 shares of our common stock, which vests as to one-third of the shares upon the achievement on or prior to March 2, 2026, but not earlier than the one-year anniversary of the grant date, of the same three specified research and development and business development milestones as our other named executive officers. The foregoing stock option award was made as an inducement to employment in accordance with Nasdaq Listing Rule 5635(c)(4) and not pursuant to the terms of our 2015 Stock Incentive Plan. (2)In connection with Dr. Burkly’s commencement of employment in July 2023, she was granted on July 24, 2023 (i) a stock option award to purchase 135,500 shares of our common stock, which vests as to 25% of the shares underlying the option on July 24, 2024 and an additional 2.0833% of the shares underlying the option at the end of each successive month following such date until July 24, 2027 and which has an exercise price of $8.66 per share, (ii) an RSU for 45,167 shares of our common stock which vests as to 25% of the shares on each anniversary of the grant date through 2027, and (iii) a PSU for 45,167 shares of our common stock, which vests as to one-third of the shares upon the achievement on or prior to March 2, 2026, but not earlier than the one-year anniversary of the grant date, upon the achievement of the same three specified research and development and business development milestones as our other named executive officers. The foregoing stock option award was made as an inducement to employment in accordance with Nasdaq Listing Rule 5635(c)(4) and not pursuant to the terms of our 2015 Stock Incentive Plan. Other Benefits Severance and Change in Control Benefits. Our amended and restated severance benefits plan (“Severance Plan”) provides severance benefits to certain of our executives, including our named executive officers, and other employees designated by our Board or an authorized committee thereof, if their employment is terminated by us without “cause” or they terminate employment with us for “good reason” (as each of those terms is defined in the Severance Plan). Under the Severance Plan, if we terminate an eligible executive officer’s employment without cause or such executive terminates his or her employment with us for good reason more than three months prior to or more than 12 months following the closing of a change in control of our company, the executive is entitled to (a) continue receiving his or her base salary for 12 months following the date of termination (the “Severance Period”), (b) company contributions to the cost of health care continuation under the Consolidated Omnibus Budget Reconciliation Act (“COBRA”) for the Severance Period, and (c) the amount of any unpaid annual bonus determined by our Board to be payable to the executive for any completed bonus period which ended prior to the date of such executive’s termination. The Severance Plan also provides that, if, within the period beginning three months prior and ending 12 months following the closing of a change in control of our company, we terminate an eligible executive officer’s employment without cause or such executive terminates his or her employment with us for good reason (each of which events, a “Change in Control Termination”), the executive is entitled to (a) continue receiving his or her base salary for a specified period (in the case of our chief executive officer, for 18 months, and in the case of other C-level officers, for 12 months) following the date of termination (“Change in Control Severance Period”), (b) company contributions to the cost of health care continuation under COBRA during the Change in Control Severance Period, (c) the amount of any unpaid annual bonus determined by our Board to be payable to the executive for any completed bonus period which ended prior to the date of such executive’s termination, and (d) an additional single lump sum bonus payment in an amount equal to the multiple of (i) a fraction the numerator of which is the number of months in the Change in Control Severance Period and the denominator of which is 12 and (ii) the eligible executive’s target annual bonus amount for the year of the Change in Control Termination. In addition, in the event of a Change in Control Termination, all of the executive’s outstanding unvested equity awards will immediately vest in full on the date of such termination. All payments and benefits provided under the Severance Plan are contingent upon the execution by the executive and effectiveness of, and the executive’s continued compliance with, a severance and release of claims agreement in a form prescribed by us that will include, at a minimum, a release of all releasable claims, non-disparagement and cooperation obligations, a reaffirmation of continuing obligations under any restrictive covenant agreements between us and the executive, and an agreement, to the extent permitted by law, not to compete with us for 12 months following separation from employment with us. Please refer to “—Employment, Severance, Change in Control Arrangements, and Separation Arrangements” below for a more detailed discussion of severance and change in control benefits for our named executive officers, including certain changes with respect to the Severance Plan for Dr. O’Neill provided in his offer letter. We believe that providing these benefits helps us compete for executive talent. These benefits are designed to promote stability and continuity of our senior management and are intended to preserve employee morale and productivity and encourage retention in the face of the disruptive impact of an actual, threatened, or rumored change of control of our company. Health and Welfare Benefits. Our named executive officers are eligible to participate in all of our employee benefit plans, including our medical, dental, vision, life and disability insurance plans, in each case, on the same basis as other employees. We believe that these health and welfare benefits help ensure that we have a productive and focused workforce through reliable and competitive health and other benefits. 401(k) Retirement Plan. We maintain a 401(k) retirement plan that is intended to be a tax-qualified defined contribution plan under Section 401(k) of the Internal Revenue Code (the “Code”). In general, all of our employees are eligible to participate, beginning on the first day of the month following commencement of their employment. The 401(k) plan includes a salary deferral arrangement pursuant to which participants may elect to reduce their current compensation by up to the statutorily prescribed limit, equal to $22,500 in 2023 plus any amounts permitted for catch-up contributions, and have the amount of the reduction contributed to the 401(k) plan. We provide a 200% match of employee contributions under our 401(k) plan, up to a limit on our contributions of the lesser of $6,000 and 3% of the employee’s salary. Perquisites. We have not generally provided perquisites or personal benefits to our named executive officers, other than relocation and housing reimbursement and related tax-gross ups in connection with certain newly hired executives.

  51. 2024 Compensation Actions

    2024 Compensation Actions In February 2024, the Compensation Committee approved salary increases and awarded annual stock option awards and RSUs for each of Mr. Lucera, Dr. Burkly and Dr. Mei. The Compensation Committee further recommended a 2024 salary increase and annual equity awards for Dr. O’Neill, as well as annual PSUs for each of the foregoing named executive officers, which the Board approved. For the 2024 annual equity grants, the Compensation Committee recommended and the Board retained the same target mix as our 2023 annual equity grants, specifically a target mix of 50% in stock options with time-based vesting, 25% in RSUs with time-based vesting and 25% in PSUs that vest only upon achievement of certain research and development milestones on or prior to the third anniversary of the initial grant date and satisfaction of a minimum one-year vesting period. In March 2024, the Compensation Committee determined that the performance requirement as to one-third of the shares subject to the PSUs granted in 2022 to Drs. O’Neill, Mei and Eaton, who were serving as executive officers at the time of grant, and one-third of the shares subject to the PSUs granted in 2023 to Mr. Lucera and Dr. Burkly, who received the applicable PSUs as part of their new hire compensation, was achieved upon our execution of the license agreement with Vertex and the related extension of our cash runway. For Mr. Lucera and Dr. Burkly, these earned shares remain subject to time-based vesting requirements until the first anniversary of their respective grant dates. In March 2024, the Compensation Committee further determined that the performance requirement as to one-third of the shares subject to the PSUs granted in 2022 to Drs. O’Neill, Mei and Eaton was achieved upon establishment of proof-of-concept for a second drug candidate, as demonstrated by our alignment with the FDA that the RUBY trial of reni-cel for SCD is now considered a single Phase 1/2/3 trial to support a biologics license application filing.

  52. Other Policies, Procedures, or Considerations

    The following forms of equity count toward the ownership guidelines: shares owned outright, vested but unexercised “in-the-money” stock options, and unvested time-based restricted stock and restricted stock units. Unvested performance-based restricted stock units do not count toward the ownership guidelines. Compliance with the policy will be determined as of June 30 each year, and covered individuals and newly appointed or elected persons have five years from when the guidelines are first applicable to them to achieve compliance with the guidelines. Directors and executive officers will be deemed to be in compliance with the stock ownership guidelines once their equity holdings meet or exceed the threshold and will remain in compliance, notwithstanding any decline in the value of shares of our common stock, unless an individual’s sale or other disposition of shares subsequently results in non-compliance with the guidelines. The guidelines were initially adopted in December 2020, so the earliest required compliance date is June 30, 2026. As of June 30, 2023, all directors and executive officers have satisfied, or are on track to satisfy the ownership guidelines within the applicable five-year grace period. Anti-Hedging and Pledging Policy. Our insider trading policy expressly prohibits all of our employees, including our named executive officers, as well as our directors, family members and controlled entities from engaging in speculative transactions in our securities, including short sales, puts/calls, purchases of financial instruments that are designed to hedge or offset any decrease in the market value of our securities, and margin accounts or pledges. No Excise Tax Gross-ups. We do not provide for any excise tax gross-up payments to our named executive officers. Accounting and Tax Considerations. We account for equity compensation paid to our employees under the rules of Financial Accounting Standards Board Accounting Standard Codification Topic 718, Compensation—Stock Compensation (“ASC Topic 718”), which requires us to estimate and record an expense over the service period of any such award. Accounting standards also require us to record cash compensation as an expense at the time the obligation is accrued. To date, these accounting requirements have not impacted our executive compensation programs and practices.

  53. 2023 Summary Compensation Table

    2023 Summary Compensation Table The following table sets forth information regarding compensation earned by our named executive officers during the years ended December 31, 2023, December 31, 2022 and December 31, 2021.

  54. 2023 Summary Compensation Table

    | Name and Principal Position | Year | Salary ($) | Bonus ($)(1) | Stock Awards ($)(2) | Option Awards ($)(3) | Non-Equity Incentive Plan Compensation ($)(4) | All Other Compensation ($)(5) | Total ($) | | Gilmore O’Neill, M.B., M.M.Sc.(6) | 2023 | 641,092 | — | 436,000 | 915,390 | 392,537 | 7,290 | 2,392,309 | | President and Chief Executive Officer | 2022 | 355,769 | — | 999,999 | 7,495,059 | 201,329 | 6,744 | 9,058,900 | | Erick Lucera(7) | 2023 | 285,615 | — | 748,619 | 1,034,512 | 146,076 | 794 | 2,215,616 | | Executive Vice President and Chief Financial Officer | | | | | | | | | | Linda C. Burkly, Ph.D.(8) | 2023 | 209,423 | — | 391,146 | 815,710 | 113,157 | 7,612 | 1,537,048 | | Executive Vice President and Chief Scientific Officer | | | | | | | | | | Baisong Mei, M.D., Ph.D.(9) | 2023 | 459,930 | — | 156,960 | 329,540 | 186,995 | 7,980 | 1,141,405 | | Senior Vice President and Chief Medical Officer | 2022 | 199,038 | 100,000 | 874,996 | 1,748,762 | 84,240 | 3,711 | 3,010,747 | | Michelle Robertson(10) | 2023 | 303,464 | — | 274,680 | 823,799 | — | 175,553 | 1,577,496 | | Former Executive Vice President and Chief Financial Officer | 2022 | 450,915 | — | 924,998 | 1,849,343 | 189,540 | 7,290 | 3,422,086 | | | 2021 | 415,754 | — | 627,408 | 977,865 | 218,700 | 7,290 | 2,247,017 | | Bruce Eaton, Ph.D.(11) | 2023 | 469,182 | — | 145,624 | 396,914 | 214,688 | 78,980 | 1,305,388 | | Former Executive Vice President and Chief Business Officer | 2022 | 448,978 | 140,000 | 649,983 | 1,299,540 | 189,267 | 7,980 | 2,735,748 | | | 2021 | 386,624 | — | 717,568 | 520,351 | 208,980 | 7,290 | 1,840,813 |

  55. 2023 Summary Compensation Table

    (1)For Dr. Mei, the amount reflects a one-time sign on bonuses received in connection with commencement of his employment. For Dr. Eaton, the amount reflects a one-time bonus awarded in January 2021 to Dr. Eaton, subject to his continued employment for one year, that was paid in January 2022. (2)Reflects the aggregate grant date fair value of stock awards granted during the year in question calculated in accordance with the provisions of ASC Topic 718. See Note 12 to our audited consolidated financial statements appearing in our 2023 Annual Report for assumptions underlying the valuation of stock awards. Stock awards for 2023 include both RSUs and PSUs. However, the 2023 PSUs had no grant date fair value, as the achievement of such PSUs was deemed not probable at the time of grant. In addition, the extension of the vesting period for Dr. Eaton’s PSUs resulted in no incremental grant date fair value, as the achievement of such PSUs was deemed not probable as of the modification date. The grant date fair values for 2023 PSUs, assuming all performance conditions are achieved, are as set forth in the below table.

  56. 2023 Summary Compensation Table

    | Name | Grant Date Fair Value 2023 PSUs ($) | | Gilmore O’Neill | 741,200 | | Erick Lucera | 748,619 | | Linda C. Burkly | 391,146 | | Baisong Mei | 313,920 | | Michelle Robertson | 274,680 | | Bruce Eaton | 145,624 |

  57. 2023 Summary Compensation Table

    (3)Reflects the aggregate grant date fair value of option awards granted during the year in question calculated in accordance with the provisions of ASC Topic 718. The 2023 aggregate grant date fair values for Ms. Robertson and Dr. Eaton include $247,103 and $91,784, respectively, representing the incremental grant date fair value, as of the modification date, calculated in accordance with ASC Topic 718 in connection with the modification of their option awards in connection with their separations from the company, as described below under “—Employment, Severance, Change in Control Arrangements, and Separation Arrangements—Ms. Robertson and Dr. Eaton Separations.” See Note 12 to our audited consolidated financial statements appearing in our 2023 Annual Report for assumptions underlying the valuation of option awards. (4)Amounts represent bonuses paid to our named executive officers under our annual performance-based cash bonus program. Such bonuses earned during the year are typically paid in the following year. (5)All other compensation for 2023 included (i) life insurance premiums for Dr. O’Neill, Mr. Lucera, Drs. Burkly and Mei, Ms. Robertson, and Dr. Eaton in the amount of $1,290, $794, $1,612, 1,980, $844, and $1,980, respectively, (ii) 401(k) company matching contributions in the amount of $6,000 for Drs. O’Neill, Burkly and Mei, Ms. Robertson, and Dr. Eaton, (iii) housing expenses in the amount of $71,000, including gross-up payments, paid to Dr. Eaton, and (iv) severance payments and benefits continuation payments to Ms. Robertson in the amounts of $166,396 and $2,314, respectively. All other compensation for 2022 included life insurance premiums for Drs. O’Neill and Mei, Ms. Robertson, and Dr. Eaton, in the amount of $744, $595, $1,290, and $1,980, respectively, and 401(k) company matching contributions in the amount of $6,000 for Dr. O’Neill, Ms. Robertson, and Dr. Eaton, and $3,115 for Dr. Mei. All other compensation for 2021 included life insurance premiums in the amount of $1,290 for Ms. Robertson and Dr. Eaton and 401(k) company matching contributions in the amount of $6,000 for Ms. Robertson and Dr. Eaton. (6)Dr. O’Neill was not a named executive officer for 2021. Therefore, the Summary Compensation Table includes compensation information for 2023 and 2022 only. The salary amount reported for 2022 reflects the prorated portion of his annual salary of $625,000 from commencement of his employment through December 31, 2022. (7)Mr. Lucera was not a named executive officer for 2022 or 2021. Therefore, the Summary Compensation Table includes compensation information for 2023 only. Mr. Lucera’s employment commenced with us in May 2023 and the salary amount reported reflects the prorated portion of his annual salary of $470,000 from commencement of his employment through December 31, 2023. (8)Dr. Burkly was not a named executive officer for 2022 or 2021. Therefore, the Summary Compensation Table includes compensation information for 2023 only. Dr. Burkly’s employment commenced with us in July 2023 and the salary amount reported reflects the prorated portion of her annual salary of $495,000 from commencement of her employment through December 31, 2023. (9)Dr. Mei was not a named executive officer for 2021. Therefore, the Summary Compensation Table includes compensation information for 2023 and 2022 only. The salary amount reported for 2022 reflects the prorated portion of his annual salary of $450,000 from commencement of his employment through December 31, 2022. (10)Ms. Robertson's employment with our company ceased on August 16, 2023 and the 2023 salary reported reflects the pro-rated portion of Ms. Robertson's annual salary of $470,250. (11)Dr. Eaton’s employment with our company ended on January 2, 2024.

  58. Grants of Plan-Based Awards

    Grants of Plan-Based Awards The following table shows information regarding grants of plan-based awards during the fiscal year ended December 31, 2023 to our named executive officers.

  59. Grants of Plan-Based Awards

    | | | | Estimated Future Payouts Under Non-Equity Incentive Plan Awards(3) | | | Estimated Future Payouts Under Equity Incentive Plan Awards(4) | | | All Other Stock Awards: Number of Shares of Stock or Units (#) | All Other Option Awards: Number of Securities Underlying Options (#) | Exercise or Base Price of Option Awards ($) | Grant Date Fair Value of Stock and Option Awards(5) ($) | | Name(1) | Date of Grant | Grant Approval Date(2) | Threshold ($) | Target ($) | Maximum ($) | Threshold (#) | Target (#) | Maximum (#) | | | | | | Gilmore O’Neill | | | — | 384,840 | 558,018 | — | — | — | — | — | — | — | | | 3/2/2023 | 2/10/2023 | — | — | — | — | — | — | 50,000(6) | — | — | 436,000 | | | 3/2/2023 | 2/10/2023 | — | — | — | — | — | — | — | 150,000(6) | 8.72 | 915,390 | | | 3/2/2023 | 2/10/2023 | — | — | — | — | 85,000 | — | — | — | — | 0 | | Erick Lucera | | | — | 141,000 | 200,220 | — | — | — | — | — | — | — | | | 5/17/2023 | 5/16/2023 | — | — | — | — | — | — | 77,900(6) | — | — | 748,619 | | | 5/17/2023 | 5/16/2023 | — | — | — | — | — | — | — | 155,800(7) | 9.61 | 1,034,512 | | | 5/17/2023 | 5/16/2023 | — | — | — | — | 77,900 | — | — | — | — | 0 | | Linda C. Burkly | | | — | 111,375 | 158,153 | — | — | — | — | — | — | — | | | 7/24/2023 | — | — | — | — | — | — | — | 45,167(6) | — | — | 391,146 | | | 7/24/2023 | — | — | — | — | — | — | — | — | 135,500(7) | 8.66 | 815,710 | | | 7/24/2023 | — | — | — | — | — | 45,167 | — | — | — | — | 0 | | Baisong Mei | | | — | 184,050 | 261,351 | — | — | — | — | — | — | — | | | 3/2/2023 | 2/10/2023 | — | — | — | — | — | — | 18,000(6) | — | — | 156,960 | | | 3/2/2023 | 2/10/2023 | — | — | — | — | — | — | — | 54,000(6) | 8.72 | 329,540 | | | 3/2/2023 | 2/10/2023 | — | — | — | — | 36,000 | — | — | — | — | 0 | | Michelle Robertson | | | — | 211,613 | 300,490 | — | — | — | — | — | — | — | | | 3/2/2023 | 2/10/2023 | — | — | — | — | — | — | 31,500(6) | — | — | 274,680 | | | 3/2/2023 | 2/10/2023 | — | — | — | — | — | — | — | 94,500(6) | 8.72 | 576,696 | | | 3/2/2023 | 2/10/2023 | — | — | — | — | 31,500 | — | — | — | — | 0 | | | 5/16/2023 | — | — | — | — | — | — | — | — | — | — | 247,103(8) | | Bruce Eaton | | | — | 211,307 | 300,056 | — | — | — | — | — | — | — | | | 3/2/2023 | 2/10/2023 | — | — | — | — | — | — | 16,700(6) | — | — | 145,624 | | | 3/2/2023 | 2/10/2023 | — | — | — | — | — | — | — | 50,000(6) | 8.72 | 305,130 | | | 3/2/2023 | 2/10/2023 | — | — | — | — | 16,700 | — | — | — | — | 0 | | | 10/3/2023 | — | — | — | — | — | — | — | — | — | — | 91,784(8) |

  60. Grants of Plan-Based Awards

    (1)For information on vesting acceleration upon termination of employment, see the “—Employment, Severance, Change in Control Arrangements, and Separation Arrangements” section below. (2)Reflects the date on which the Board or the Compensation Committee, as applicable, took action to grant the equity award where such date is different than the grant date. (3)Reflects payments under our annual performance-based cash bonus program, which does not require any minimum criteria for a named executive officer to participate in such program. Target and maximum amounts of estimated future payouts under non-equity incentive plan awards are determined as set forth under “—Compensation Discussion and Analysis—Executive Compensation Elements & Decisions—Annual Performance-based Cash Bonus,” using corporate and individual goal achievement percentages of 100% for target and corporate and individual performance percentages of 145% and 130%, respectively, for the maximum. The actual amounts earned by each named executive officer are set forth in the Summary Compensation Table. For Mr. Lucera and Dr. Burkly, the amounts reflect the pro-rated portion of their respective target bonus amounts from commencement of employment through December 31, 2023. (4)Reflects performance-based equity awards granted in 2023 under our 2015 Stock Incentive Plan. These awards vest only upon achievement of specified performance conditions, and do not provide for any increase or decrease in the number of awards that vest for each performance metric based on the level of performance. (5)Reflects the grant date fair values of stock and option awards granted during the year in question calculated in accordance with the provisions of ASC Topic 718. See Note 12 to our audited consolidated financial statements appearing in our 2023 Annual Report for assumptions underlying the valuation of equity awards. The grant date fair value for performance-based equity awards is based on the probable outcome of each of the performance conditions as of such grant date. (6)Represents RSUs and stock option awards granted in 2023 under our 2015 Stock Incentive Plan. For Drs. O'Neill and Mei, the amounts reflect proration of the grant date fair value of the equity awards from commencement of employment through December 31, 2022. (7)Inducement award granted pursuant to the inducement grant exception under Nasdaq Stock Market Rule 5635(c), which inducement award was not subject to our 2015 Stock Incentive Plan. (8)Represents the incremental grant date fair value, as of the modification date, calculated in accordance with ASC Topic 718 in connection with the modification of Ms. Robertson’s and Dr. Eaton’s option awards in connection with their separations from the company, as described below under “—Employment, Severance, Change in Control Arrangements, and Separation Arrangements—Ms. Robertson and Dr. Eaton Separations.” The extension of the vesting period for Dr. Eaton’s PSUs resulted in no incremental grant date fair value, as the achievement of such PSUs was deemed not probable as of the modification date.

  61. Outstanding Equity Awards at Fiscal Year-End

    Outstanding Equity Awards at Fiscal Year-End The following table sets forth information concerning outstanding equity awards for each of our named executive officers at December 31, 2023.

  62. Outstanding Equity Awards at Fiscal Year-End

    | | | Option Awards(1) | | | | | Stock Awards(2) | | | | | Name | Grant Date | Number of Securities Underlying Unexercised Options Exercisable (#) | Number of Securities Underlying Unexercised Options Unexercisable (#) | Equity Incentive Plan Awards: Number of Securities Underlying Unexercised Unearned Options (#) | Option Exercise Price ($) | Option Expiration Date | Number of Shares or Units of Stock That Have Not Vested (#) | Market Value of Shares or Units of Stock That Have Not Vested ($) | Equity Incentive Plan Awards: Number of Unearned Shares, Units or Other Rights that Have Not Vested (#) | Equity Incentive Plan Awards: Market or Payout Value of Unearned Shares, Units or Other Rights that Have not Vested ($) | | Gilmore O’Neill | 6/2/2022 | 356,328 | 593,881(3) | — | 11.54 | 6/1/2032 | — | — | — | — | | | 6/2/2022 | — | — | — | — | — | 64,991(4) | 658,359 | — | — | | | 6/2/2022 | — | — | — | — | — | — | — | 216,637(5) | 2,194,533 | | | 3/2/2023 | 28,125 | 121,875(6) | — | 8.72 | 3/1/2033 | — | — | | — | | | 3/2/2023 | — | — | — | — | — | 50,000(7) | 506,500 | — | — | | | 3/2/2023 | — | — | — | — | — | — | — | 85,000(8) | 861,050 | | Erick Lucera | 5/17/2023 | — | 155,800(9) | — | 9.61 | 5/16/2033 | — | — | — | — | | | 5/17/2023 | — | — | — | — | — | 77,900(10) | 789,127 | — | — | | | 5/17/2023 | — | — | — | — | — | — | — | 77,900(11) | 789,127 | | Linda C. Burkly | 7/24/2023 | — | 135,000(12) | — | 8.66 | 7/23/2033 | — | — | — | — | | | 7/24/2023 | — | — | — | — | — | 45,167(13) | 457,542 | — | — | | | 7/24/2023 | — | — | — | — | — | — | — | 45,167(11) | 457,542 | | Baisong Mei | 7/18/2022 | 60,775 | 110,827(14) | — | 14.99 | 7/17/2032 | — | — | — | — | | | 7/18/2022 | — | — | — | — | — | 43,779(15) | 443,481 | — | — | | | 7/18/2022 | — | — | — | — | — | — | — | 58,372(5) | 591,308 | | | 3/2/2023 | 10,125 | 43,875(6) | — | 8.72 | 3/1/2033 | — | — | | — | | | 3/2/2023 | — | — | — | — | — | 18,000(7) | 182,340 | — | — | | | 3/2/2023 | — | — | — | — | — | — | — | 36,000(8) | 364,680 | | Michelle Robertson(16) | 1/9/2020 | 102,500 | — | — | 30.65 | 1/18/2030 | — | — | — | — | | | 3/2/2021 | 19,452 | — | — | 45.69 | 3/1/2031 | — | — | — | — | | | 2/10/2022 | 32,829 | — | — | 17.29 | 2/9/2032 | — | — | — | — | | | 3/2/2023 | 9,844 | — | — | 8.72 | 3/1/2033 | — | — | — | — | | Bruce Eaton(17) | 2/5/2018 | 110,000 | — | — | 33.98 | 2/4/2028 | — | — | — | — | | | 2/6/2019 | 48,750 | — | — | 21.10 | 2/5/2029 | — | — | — | — | | | 2/6/2020 | 43,132 | 1,875(18) | — | 28.05 | 2/5/2030 | — | — | — | — | | | 2/6/2020 | — | — | — | — | — | 469(19) | 4,751 | — | — | | | 3/2/2021 | 11,779 | 5,354(20) | — | 45.69 | 3/1/2031 | — | — | — | — | | | 3/2/2021 | — | — | — | — | — | 1,713(21) | 17,353 | — | — | | | 6/2/2021 | — | — | — | — | — | — | — | 6,944(22) | 70,343 | | | 2/10/2022 | 50,752 | 59,980(23) | — | 17.29 | 2/9/2032 | — | — | — | — | | | 2/10/2022 | — | — | — | — | — | 21,146(24) | 214,209 | — | — | | | 2/10/2022 | — | — | — | — | — | — | — | 37,593(5) | 380,817 | | | 3/2/2023 | 9,375 | 40,625(6) | — | 8.72 | 3/1/2033 | | | | | | | 3/2/2023 | — | — | — | — | — | 16,700(7) | 169,171 | — | — | | | 3/2/2023 | — | — | — | — | — | — | — | 16,700(8) | 169,171 |

  63. Outstanding Equity Awards at Fiscal Year-End

    (1)All unvested stock options were granted under our 2015 Stock Incentive Plan, except for the grants discussed in footnotes 9 and 12, which were inducement grants approved by our Board. For information on vesting acceleration upon termination of employment, see the “—Employment, Severance, Change in Control Arrangements, and Separation Arrangements” section below. (2)All unvested RSUs and unearned PSUs were granted under our 2015 Stock Incentive Plan. For information on vesting acceleration upon termination of employment, see the “—Employment, Severance, Change in Control Arrangements, and Separation Arrangements” section below. The market value of unvested RSUs and unearned PSUs are based on a price of $10.13 per share, which was the closing price of our common stock as reported on the Nasdaq Global Select Market on December 29, 2023, the last trading day of the fiscal year. (3)The shares underlying this option vested as to 25% of the shares on June 2, 2023 and an additional 2.0833% of the shares underlying the option vest at the end of each successive month following such date. (4)The shares underlying this RSU vest as to one-fourth of the shares on each of June 2, 2023, 2024, 2025, and 2026. (5)The shares underlying this PSU vest as to one-third of the shares on the achievement of certain research and development and business development milestones on or prior to February 10, 2025, provided no shares subject to this award may vest prior to the one-year anniversary of each recipient’s grant date. On March 2, 2024, the Compensation Committee confirmed the achievement of a research and development milestone and the business development milestone, resulting in an aggregate of 144,425, 38,915, and 25,062 of the shares underlying this PSU vesting for Drs. O’Neill, Mei and Eaton, respectively, on such date. (6)The shares underlying this option vest over four years in equal monthly installments beginning on April 2, 2023 through March 2, 2027. (7)The shares underlying this RSU vest over four years with 25% of the shares vesting on March 2, 2024 and the remaining 75% of the shares scheduled to vest in equal quarterly installments thereafter through March 2, 2027. (8)The shares underlying this PSU vest as to one-third of the shares on the achievement of certain research and development and business development milestones on or prior to March 2, 2026, provided no shares subject to this award may vest prior to the one-year anniversary of each recipient’s grant date. (9)The shares underlying this option vested as to 25% of the shares on May 17, 2024 and an additional 2.0833% of the shares underlying the option vest at the end of each successive month following such date. (10)The shares underlying this RSU vest as to one-fourth of the shares on each of May 17, 2024, 2025, 2026 and 2027. (11)The shares underlying this PSU vest as to one-third of the shares on the achievement of certain research and development and business development milestones on or prior to March 2, 2026, provided no shares subject to this award may vest prior to the one-year anniversary of each recipient’s grant date. On March 2, 2024, the Compensation Committee confirmed the achievement of the business development milestone for Mr. Lucera and Dr. Burkly, resulting in 25,966 and 15,055 of the shares underlying this PSU being earned by Mr. Lucera and Dr. Burkly, respectively, on such date. These earned shares remain subject to time-based vesting conditions until the one year anniversary of their respective grant dates. (12)The shares underlying this option vested as to 25% of the shares on July 24, 2024 and an additional 2.0833% of the shares underlying the option vest at the end of each successive month following such date. (13)The shares underlying this RSU vest as to one-fourth of the shares on each of July 24, 2024, 2025, 2026 and 2027. (14)The shares underlying this option vest as to 25% of the shares on July 18, 2023 and an additional 2.0833% of the shares underlying the option vest at the end of each successive month following such date. (15)The shares underlying this RSU vest as to one-fourth of the shares on each of July 18, 2023, 2024, 2025, and 2026. (16)Ms. Robertson’s employment with our company ceased on August 16, 2023, at which time her outstanding unvested stock options, unvested RSUs, and unearned PSUs were forfeited. Pursuant to her separation agreement, Ms. Robertson has 12 months following her separation date to exercise her outstanding stock options that had vested as of such date. (17)Dr. Eaton’s employment with our company ceased on January 2, 2024, at which time his outstanding unvested stock options and unvested RSUs were forfeited. Pursuant to his separation agreement, Dr. Eaton has 12 months following his separation date to exercise his outstanding stock options that had vested as of such date. His separation agreement further provides that any PSUs unearned as of his separation date will remain outstanding and become vested to the extent that the applicable performance metrics are determined by the Board or the Compensation Committee to have been achieved on or prior to March 31, 2024, provided that such achievement is certified by the Board or the Compensation Committee no later than April 30, 2024. (18)The shares underlying this option vest over four years in equal monthly installments beginning on March 6, 2020 through February 6, 2024. (19)The shares underlying this RSU vest over four years with 25% of the units having vested on February 6, 2021 and the remaining 75% of the units scheduled to vest in equal quarterly installments thereafter through February 6, 2024. (20)The shares underlying this option vest over four years in equal monthly installments beginning on April 2, 2021 through March 2, 2025. (21)The shares underlying this RSU vest over four years with 25% of the shares having vested on March 2, 2022 and the remaining 75% of the shares scheduled to vest in equal quarterly installments thereafter through March 2, 2025. (22)The shares underlying this PSU vest as to one-third of the shares on the achievement of certain research and development milestones on or prior to the third anniversary of the grant date, one of which has been achieved, provided no shares subject to this award could vest prior to the one-year anniversary of the grant date. (23)The shares underlying this option vest over four years in equal monthly installments beginning on March 10, 2022 through February 10, 2025. (24)The shares underlying this RSU vest over four years with 25% of the shares vesting on February 10, 2023 and the remaining 75% of the shares scheduled to vest in equal quarterly installments thereafter through February 10, 2026.

  64. Option Exercises and Stock Vested

    Option Exercises and Stock Vested The following table sets forth information concerning stock vested for each of our named executive officers during the fiscal year ended December 31, 2023. There were no option exercises by our named executive officers during this period.

  65. Option Exercises and Stock Vested

    | | Stock Awards | | | Name | Number of shares acquired on vesting (#) | Value realized on vesting ($)(1) | | Gilmore O’Neill | 21,664 | 209,491 | | Erick Lucera | — | — | | Linda C. Burkly | — | — | | Baisong Mei | 14,593 | 127,251 | | Michelle Robertson | 26,350 | 245,839 | | Bruce Eaton | 20,201 | 189,903 |

  66. Option Exercises and Stock Vested

    (1)The value realized on vesting is based on the closing market price per share of our common stock on the Nasdaq Global Select Market on the vesting date, or if the Nasdaq Global Select Market was not open on such vesting date the next trading date, multiplied by the number of shares of restricted stock that vested.

  67. Potential Payments upon Termination or Change in Control

    Potential Payments upon Termination or Change in Control As more fully discussed above in Compensation Discussion and Analysis, we provide severance benefits to certain of our executives, including our named executive officers, and other employees designated by our Board or an authorized committee thereof, if their employment is terminated by us without “cause” or, only in connection with a “change in control” of our company, they terminate employment with us for “good reason” (as each of those terms is defined in the Severance Plan) pursuant to the terms of our Severance Plan. The following table sets forth potential payments upon termination and change in control that would be made to our named executive officers, assuming that such termination or change in control occurred on December 31, 2023, after giving effect to the Severance Plan, except for Ms. Robertson, with respect to whom the disclosed amounts represent what she was actually paid in connection with her separation in August 2023. In addition to the amounts shown in the table below, each named executive officer would be entitled to receive payments for base salary through the date of termination and payment for any reimbursable business expenses incurred.

  68. Potential Payments upon Termination or Change in Control

    | | | Triggering Event | | | Name | Benefit | Resignation For Good Reason or Termination Without Cause - No Change-in-Control ($) | Resignation For Good Reason or Termination Without Cause Within Three Months Prior To or One Year Following a Change-in-Control ($) | | Gilmore O’Neill | Severance Payments(1) | 641,400 | 962,100 | | | Bonus Payment(2) | 392,537 | 392,537 | | | Continuation of Benefits | 8,320 | 12,481 | | | Market Value of Stock Vesting(3) | — | 4,392,285 | | | Total | 1,042,257 | 5,759,403 | | Erick Lucera | Severance Payments(1) | 470,000 | 470,000 | | | Bonus Payment | —(4) | 146,076(5) | | | Continuation of Benefits | 8,320 | 8,320 | | | Market Value of Stock Vesting(3) | — | 1,659,270 | | | Total | 478,320 | 2,283,666 | | Linda C. Burkly | Severance Payments(1) | 495,000 | 495,000 | | | Bonus Payment | —(4) | 113,157(5) | | | Continuation of Benefits | 8,320 | 8,320 | | | Market Value of Stock Vesting(3) | — | 1,114,268 | | | Total | 503,320 | 1,730,746 | | Baisong Mei | Severance Payments(1) | 460,125 | 460,125 | | | Bonus Payment | —(4) | 186,995(5) | | | Continuation of Benefits | 8,320 | 8,320 | | | Market Value of Stock Vesting(3) | — | 1,643,673 | | | Total | 468,445 | 2,299,114 | | Michelle Robertson(6) | Severance Payments | 470,250 | — | | | Bonus Payment | — | — | | | Continuation of Benefits | 2,314 | — | | | Market Value of Stock Vesting | — | — | | | Total | 472,564 | — | | Bruce Eaton(7) | Severance Payments(1) | 469,571 | 469,571 | | | Bonus Payment | —(4) | 214,688(5) | | | Continuation of Benefits | 23,714 | 23,714 | | | Market Value of Stock Vesting(3) | — | 1,083,096 | | | Total | 493,285 | 1,791,068 |

  69. Potential Payments upon Termination or Change in Control

    (1)Represents 12 monthly payments of each executive’s monthly base salary from the time of termination, except in the case of a termination of Dr. O’Neill by the company without cause or by Dr. O’Neill for good reason, in either case which occurs within the period beginning three months prior to and ending 12 months following a change in control (as defined in the Severance Plan). Under such circumstances, Dr. O’Neill would be entitled to receive 18 monthly payments of his monthly base salary from the time of termination. (2)Pursuant to the offer letter, dated April 13, 2022, between the company and Dr. O’Neill, he is entitled to severance benefits in accordance with the Severance Plan, provided that (i) he is entitled to receive a pro rata annual bonus upon a non-change of control termination and (ii) a non-change of control termination is defined as a termination of employment by the company without cause or by Dr. O’Neill for good reason (with cause and good reason as defined in the Severance Plan) which occurs more than three months prior to or twelve months following a change of control (as defined in the Severance Plan) and a change of control termination shall be defined as a termination of employment by the company or by Dr. O’Neill for good reason which occurs three months prior to or twelve months following a change of control. (3)These awards would become vested and the value of the acceleration would be equal to the shares multiplied by (i) in the case of stock options, the excess of the then current stock price over the exercise price of the options for options and (ii) in the case of RSUs and PSUs, the then current stock price. For purposes of this table, we have calculated the value of the acceleration using the closing price of our common stock on December 30, 2023, which was $10.13 per share. (4)Under our Severance Plan, our named executive officers, other than Dr. O’Neill, would not have been eligible for bonuses for 2023 if their employment was terminated on December 31, 2023 because the bonus period would not have ended prior to such termination. Even if entitled, such performance-based cash bonus is granted at the discretion of the Compensation Committee or the Board. (5)Amount represents a lump sum payment equal to the target bonus amount multiplied by a fraction the numerator of which is the number of months the named executive officer is entitled to severance, which would be 12 months, and the denominator of which is twelve, payable on the date on which the release signed by the named executive officer becomes effective. (6)Represents the amounts payable pursuant to the separation agreement we entered into with Ms. Robertson in May 2023. (7)The information presented in this table for Dr. Eaton assumes that the triggering event took place on the last business day of our most recently completed fiscal year. As described above under the heading “—Employment, Severance, Change in Control Arrangements, and Separation Arrangements,” Dr. Eaton separated from the company on January 2, 2024. Pursuant to his separation agreement, Dr. Eaton is eligible to receive (i) his base salary for a period of 12 months following his separation date, equal to $469,571, his 2023 bonus as determined by the Board or the Compensation Committee in connection with the determination of annual bonuses for our other executives, equal to $214,688, and benefits continuation for up to 12 months, equal to $23,714. In addition, the agreement provides that (i) the period of time for Dr. Eaton to exercise all or any stock options that are outstanding and vested as of his separation date will be extended to January 2, 2025 and (ii) Dr. Eaton's outstanding PSUs remained outstanding and eligible to become earned and vested to the extent that the applicable performance metrics were determined to have been achieved on or prior to March 31, 2024, provided that such achievement was certified by the Board or the Compensation Committee no later than April 30, 2024.

  70. Pay Ratio Disclosure

    Pay Ratio Disclosure As required by Section 953(b) of the Dodd-Frank Wall Street Reform and Consumer Protection Act and Item 402(u) of Regulation S-K, we are required to disclose the ratio of the annual total compensation of the individual identified as our paid median employee to the annual total compensation of our principal executive officer. The paragraphs that follow describe our methodology and the resulting pay ratio. We identified a median employee using our employee population as of December 31, 2023 by (i) aggregating for each applicable employee (A) annual base salary for salaried employees (or hourly rate multiplied by expected annual work schedule, for hourly employees), (B) actual bonus for 2023, and (C) the grant date fair value of any annual or new hire equity awards granted during the fiscal year ended December 31, 2023, and (ii) ranking this aggregated compensation measure for our employees (excluding our chief executive officer) from highest to lowest. Salaries or wages for those employees hired during 2023 were annualized. Once the median employee was identified, we calculated the median employee’s annual total compensation in accordance with the rules applicable to the Summary Compensation Table. The total compensation for 2023 for our median employee, identified as discussed above, was $180,036. Our chief executive officer's compensation as reported in the Summary Compensation Table was $2,392,309. Therefore, our pay ratio is approximately 13 to 1. The pay ratio reported above is a reasonable estimate calculated in a manner consistent with SEC rules based on our internal records and the methodology described above. The SEC rules for identifying the median compensated employee and calculating the pay ratio based on that employee’s annual total compensation allow companies to adopt a variety of methodologies, to apply certain exclusions, and to make reasonable estimates and assumptions that reflect their employee populations and compensation practices. Therefore, the pay ratio reported by other companies may not be comparable to the pay ratio reported above, as other companies have different employee populations and compensation practices and may utilize different methodologies, exclusions, estimates and assumptions in calculating their own pay ratios.

  71. Pay Versus Performance

    Pay Versus Performance The following table sets forth compensation information for our chief executive officer (“PEO” in the table) for each year and the average of the other named executive officers (“NEOs”) for each year, our cumulative total shareholder return (“TSR”), the cumulative TSR of our peer index, the Nasdaq Biotechnology Index, and our net loss for each of the years indicated. As a clinical stage gene editing company, we do not use any financial performance measures in our compensation program or for comparison to any corporate goals. Our executives’ compensation is shown using the total from the Summary Compensation Table and Compensation Actually Paid (“CAP”), calculated in accordance with Item 402(v) of Regulation S-K. For detail on our executive compensation programs, see “Compensation Discussion and Analysis” beginning on page 31. Pay Versus Performance Table

  72. Pay Versus Performance

    | Year | Summary Compensation Table Total for Gilmore O’Neill ($)(1) | Summary Compensation Table Total for James Mullen ($)(1) | Summary Compensation Table Total for Cynthia Collins ($)(1) | Compensation Actually Paid to Gilmore O’Neill ($)(1)(2) | Compensation Actually Paid to James Mullen ($)(1)(2) | Compensation Actually Paid to Cynthia Collins ($)(1)(2) | Average Summary Compensation Table Total for Non-PEO NEOs ($)(3) | Average Compensation Actually Paid to Non-PEO NEOs ($)(3)(4) | Value of Initial Fixed $100 Investment Based On: | | Net Loss ($)(in thousands) | | | | | | | | | | | Editas Total Shareholder Return ($) | Peer Group Total Shareholder Return ($)(5) | | | 2023 | 2,392,309 | — | — | 3,764,809 | — | — | 1,555,391 | 1,575,614 | 34.21 | 118.87 | (153,219) | | 2022 | 9,058,900 | 1,050,963 | — | 6,493,262 | (2,912,999) | — | 2,880,375 | 888,434 | 29.96 | 113.65 | (220,432) | | 2021 | — | 6,714,511 | 662,427 | — | 8,874,156 | (16,539,214) | 2,115,079 | (1,272,199) | 89.67 | 126.45 | (192,502) | | 2020 | — | — | 3,115,950 | — | — | 28,342,079 | 1,851,910 | 3,862,256 | 236.78 | 126.42 | (115,976) |

  73. Pay Versus Performance

    (1) Gilmore O’Neill was appointed chief executive officer effective June 1, 2022. James Mullen served as chief executive officer from February 15, 2021 to June 1, 2022. Cynthia Collins served as chief executive officer for all of 2020 and through February 15, 2021. (2) The dollar amounts reported represent the amount of CAP to the PEO computed in accordance with Item 402(v) of Regulation S-K. The dollar amounts do not reflect the actual amount of compensation earned by or paid to any PEO during the applicable year. In accordance with the requirements of Item 402(v) of Regulation S-K, the following adjustments were made to PEO total compensation for each year to determine the CAP:

  74. Director Compensation

    Director Compensation Under our director compensation program, we pay our non-employee directors a cash retainer for service on the Board and for each committee on which the director serves. The chair of our Board and of each committee receive higher retainers for such service. These fees are payable in arrears in four equal quarterly installments on the last day of each quarter, provided that the amount of such payment is prorated for any portion of such quarter that the director was not serving on our Board or the relevant committee thereof. Dr. O’Neill, our chief executive officer, receives no compensation for his service as a director. The compensation earned by Dr. O’Neill during 2023 is presented in the “Summary Compensation Table” above. The fees paid in 2023 to non-employee directors for service on the Board and for service on each committee of the Board on which the director is a member were as follows:

  75. Director Compensation

    | | Member Annual Fee | Chair Annual Fee | | Board of Directors | $40,000 | $75,000 | | Audit Committee | $7,500 | $15,000 | | Organization, Leadership and Compensation Committee | $5,000 | $12,000 | | Nominating and Corporate Governance Committee | $5,000 | $10,000 | | Science and Technology Committee | $5,000 | $10,000 |

  76. Director Compensation

    Effective January 1, 2024, the Board increased the member annual fees and chair annual fees for the Audit Committee to $8,750 and $18,750, respectively, and for the Organization, Leadership and Compensation Committee to $7,500 and $15,000, respectively. Any non-employee director serving as the Board-appointed lead independent director also receives an annual fee of $25,000, in addition to any fees such director receives for his or her service on the Board or any committees thereof. We also reimburse our non-employee directors for reasonable travel and other expenses incurred in connection with attending our Board and committee meetings. Additionally, our Board may establish other committees from time to time that include fees for both members and chairpersons, as well as per meeting fees. In addition, under our amended director compensation program, each non-employee director receives under our 2015 Stock Incentive Plan, upon his or her initial election to our Board, a stock option having a grant date fair value of $600,000, as calculated by us in accordance with ASC Topic 718, subject to a maximum of 50,000 shares of our common stock. Each of these options vests as to one-third of the shares of our common stock underlying such option on each anniversary of the grant date until the third anniversary of the grant date, subject to the non-employee director’s continued service as a director through such vesting date. Further, on the date of the first Board meeting held after each annual meeting of stockholders, each non-employee director that has served on the Board for at least four months receives, under our 2015 Stock Incentive Plan, a stock option having a grant date fair value of $300,000, as calculated by us in accordance with ASC Topic 718 with the terms of such option as set forth in this paragraph, subject to a maximum of 25,000 shares of our common stock. Each of these options vest in full on the one-year anniversary of the grant date, subject to the non-employee director’s continued service as a director through such vesting date. All options issued to our non-employee directors under our director compensation program are issued at exercise prices equal to the fair market value of our common stock on the date of grant and become exercisable in full upon a change in control of our company. The following table sets forth information regarding compensation earned by our non-employee directors and James C. Mullen, who served as our executive chair until June 1, 2023, during the year ended December 31, 2023.

  77. Director Compensation

    | Name | Fees earned or paid in cash ($) | Option awards ($)(1) | All Other Compensation | Total ($) | | Meeta Chatterjee, Ph.D. | 47,500 | 158,060 | — | 205,560 | | Bernadette Connaughton | 57,000 | 158,060 | — | 215,060 | | Andrew Hirsch | 52,500 | 158,060 | — | 210,560 | | Jessica Hopfield, Ph.D. | 73,008 | 158,060 | — | 231,068 | | Elliott Levy, M.D.(2) | 37,788 | 227,095 | — | 264,883 | | James C. Mullen(3) | — | — | 168,152 | 168,152 | | Emma Reeve | 80,179 | 158,060 | — | 238,239 | | David T. Scadden, M.D. | 55,000 | 158,060 | — | 213,060 | | Akshay K. Vaishnaw, M.D., Ph.D. | 50,000 | 158,060 | — | 208,060 |

  78. Director Compensation

    (1)Reflects the aggregate grant date fair value of option awards granted during the year in question calculated in accordance with the provisions of ASC Topic 718. See Note 12 to our audited consolidated financial statements appearing in our 2023 Annual Report for assumptions underlying the valuation of equity awards. The aggregate number of shares of common stock underlying stock options outstanding as of December 31, 2023 for our non-employee directors were: Dr. Chatterjee: 84,614, Ms. Connaughton: 74,732; Mr. Hirsch: 119,228; Dr. Hopfield: 107,690; Dr. Levy: 50,000; Ms. Reeve: 63,736; Dr. Scadden: 96,152; and Dr. Vaishnaw: 130,766. (2)Dr. Levy joined our Board on April 11, 2023. Dr. Levy was granted an option to purchase 50,000 shares on April 11, 2023 in connection with his election to our Board. Such option had an exercise price of $6.71 per share, which was the closing price of our common stock on the date of grant, and is scheduled to vest over three years in equal yearly installments of one-third of the shares beginning on April 11, 2024 through April 11, 2026. (3)Mr. Mullen received no compensation for his service as a director in 2023. Mr. Mullen did not stand for reelection and his term expired on June 1, 2023. Pursuant to his employment offer letter, as amended, in 2023 Mr. Mullen received (i) $149,894, reflecting the prorated portion of his $327,500 base salary through June 1, 2023, (ii) life insurance premiums in the amount of $1,758, and (iii) $16,500 in reimbursements for health care premiums resulting from his election not to participate in our company’s employee health benefit plans.