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Thomas Cahill

Director at Prime Medicine
Board

About Thomas Cahill

Thomas Cahill, M.D., Ph.D., is an independent Class III director of Prime Medicine (PRME), age 38 as of April 22, 2025, and has served on the board since November 2021 . He is the Founder and Managing Partner of Newpath Partners, a life sciences venture fund, and holds M.D. and Ph.D. degrees from Duke University and an M.S. from Stanford University, bringing a blend of medical and venture capital expertise to the board . The board has no chair or lead independent director; directors meet in executive session at each regularly scheduled board meeting .

Past Roles

OrganizationRoleTenureCommittees/Impact
Raptor Group HoldingsAdvisor (life science and technology investment)Sep 2016 – May 2018Helped establish and lead life science and technology investment portfolio

External Roles

OrganizationRoleTenure/Notes
Newpath PartnersFounder & Managing PartnerBoston-based life science venture fund focused on therapeutics
Chroma Medicine, Inc.Founding investor and DirectorCurrent
Exo Therapeutics, Inc.Founding investor and DirectorCurrent
Kisbee Therapeutics, Inc.Founding investor and DirectorCurrent
Kojin Therapeutics, Inc.Founding investor and DirectorCurrent
Magnet Biomedicine, Inc.Founding investor and DirectorCurrent
Myeloid Therapeutics, Inc.Founding investor and DirectorCurrent
Nvelop Therapeutics, Inc.Founding investor and DirectorCurrent
Resonance Medicine, Inc.Founding investor and DirectorCurrent

Board Governance

  • Committee assignments (as of Apr 22, 2025): Audit Committee – Member; Nominating & Corporate Governance Committee – Member .
  • Committee chair roles: None (Michael Kelly chairs Audit; David Schenkein chairs Nominating & Corporate Governance) .
  • Audit Committee activity: met five times in 2024; selected PwC as 2025 auditor; Michael Kelly designated audit committee financial expert .
  • Independence: Board determined all directors except the then-CEO and Jeffrey Marrazzo were independent in 2024; determination considered affiliations with major stockholders (covers Cahill as an affiliate of Newpath) .
  • Attendance: In 2024, each incumbent director except Robert Nelsen attended at least 75% of aggregate board and applicable committee meetings; board held six meetings, with executive sessions of non‑employee directors at each regularly scheduled meeting .
  • Board leadership: No chairperson or lead director designated; structure reviewed by independent directors .
  • Election cycle: Class III director; nominated for re‑election in 2025 to a three‑year term (plurality vote standard) .

Fixed Compensation

YearFees Earned or Paid in Cash ($)Notes
202457,188Annual director cash compensation; reflects committee service and mid‑2024 retainer increases
202352,500Annual director cash compensation

Director cash retainer policy (amended May 17, 2024):

  • Board member retainer: $45,000; Audit member: $10,000; Nominating & Corporate Governance member: $5,000; Audit chair: $20,000; Comp chair/member: $15,000 / $7,500; Board chair: $30,000 .

Implication: Cahill’s role set implies a $60,000 annualized cash retainer post‑May 2024 (Board + Audit member + N&CG member), with 2024 actuals reflecting prorations from in‑year increases .

Performance Compensation

YearOption Awards (Grant‑Date Fair Value, $)Shares Granted (Director Annual Grant)Vesting
2024237,52845,000Annual director option vests in full on earlier of 1‑year anniversary or next AGM, subject to service
2023399,46039,062Annual director option; policy prior to May 2024 reflected smaller share cap pre‑increase
  • Initial director grant policy (if applicable): $800,000 value, capped at 90,000 shares; vests in equal annual installments over three years, subject to service .
  • 2025 special action (Option Repricing proposal): All current non‑employee directors as a group (7 persons) had 958,920 “Eligible Options” (weighted avg. exercise price $10.67) that would be repriced if approved; board acknowledges the proposal may benefit employees and directors .

RED FLAG: Option repricing can be viewed as shareholder‑unfriendly; governance risk increases when directors participate in repricing .

Other Directorships & Interlocks

CompanyPublic/PrivateRolePotential Interlock/Exposure
Chroma Medicine, Exo Therapeutics, Kisbee Therapeutics, Kojin Therapeutics, Magnet Biomedicine, Myeloid Therapeutics, Nvelop Therapeutics, Resonance MedicineFounding investor and DirectorVenture portfolio affiliations; board considered stockholder affiliations in independence determinations

Expertise & Qualifications

  • Education: M.D. and Ph.D. (Duke University); M.S. (Stanford University) .
  • Core credentials: Medical and venture capital industry experience; board cites medical and VC background in qualification assessment .
  • Committee experience: Audit and Nominating & Corporate Governance member .

Equity Ownership

Holder/VehicleShares/UnitsAs‑Of/ContextNotes
Newpath Partners L.P. (beneficial ownership filed by Newpath entities and Thomas Cahill)6,105,679Schedule 13G/A filed Feb 14, 2025Cahill is managing member of Newpath GP LLC, the GP of Newpath Partners GP, L.P., which is the GP of Newpath Partners L.P.
Options outstanding (Cahill)84,062As of Dec 31, 2024 (aggregate options held)From director compensation footnote; cumulative as of year‑end 2024
Policy on hedging/pledgingPolicy disclosureCompany prohibits short sales and derivatives; policy addresses pledging risks; no Cahill‑specific pledging disclosure in proxy

Alignment: Significant indirect ownership via Newpath indicates meaningful skin‑in‑the‑game; independence determination explicitly considered major stockholder affiliations .

Governance Assessment

  • Strengths

    • Independent director with medical and venture capital expertise; active service on Audit and Nominating & Corporate Governance committees .
    • Attendance threshold met (≥75%); board held six meetings in 2024 with executive sessions at each regularly scheduled meeting .
    • Audit Committee robust activity (five meetings in 2024) and auditor oversight; PwC selected for 2025 .
  • Watch‑items / RED FLAGS

    • Option Repricing proposal in 2025 covered non‑employee directors (group eligible options 958,920 at $10.67 WAP); repricing of underwater options is commonly viewed as unfavorable to shareholders and may weaken pay‑for‑performance optics .
    • Affiliation with significant shareholder (Newpath Partners) introduces potential perceived conflicts; board states it considered these relationships in its independence assessment .
    • No designated chair or lead independent director, which some investors view as a governance weakness in oversight structure .
  • Compensation structure signals

    • Shift to larger capped annual option grants (45,000 shares cap) and higher cash retainers post‑May 2024; increases may be consistent with market alignment but raise cash/equity mix optics year‑over‑year .
    • Director compensation delivered fully in options (no RSUs/PSUs disclosed for directors), maintaining performance linkage through share price; however, the 2025 repricing proposal undermines that linkage if approved .

Director Compensation Details (Reference)

ComponentPolicy / ActualsDetail
Cash retainer (Board)$45,000 policy (as of May 17, 2024)Increased from $40,000; prorated for 2024
Audit Committee$10,000 member; $20,000 chairCahill is a member
Nominating & Corporate Governance$5,000 member; $10,000 chairCahill is a member
2024 Director cash (Cahill)$57,188Actual paid in 2024
2023 Director cash (Cahill)$52,500Actual paid in 2023
2024 Option award (Cahill)$237,528; 45,000 optionsAnnual grant; vest at next AGM or 1 year
2023 Option award (Cahill)$399,460; 39,062 optionsAnnual grant
Initial Director Grant (policy)$800,000 (max 90,000 options)Vests over three years (annual installments)

Additional Disclosures

  • Election: Cahill nominated for re‑election as Class III director in 2025 for a three‑year term; plurality voting standard applies .
  • Independence/Conflicts Oversight: Nominating & Corporate Governance Committee oversees risks associated with board independence and potential conflicts .
  • Board Risk Oversight: Board oversees operational, liquidity, credit, and cybersecurity risks; committees oversee compensation, financial reporting, and independence/conflicts risks .