Jonathan Leff
About Jonathan Leff
Jonathan Leff (age 56 as of August 2025) is an independent Class III director of PHGE, serving since March 2024. He is a Partner at Deerfield Management Company and Chairman of the Deerfield Institute (joined 2013), previously Managing Director at Warburg Pincus (2000–2012). He holds an A.B. from Harvard University, an MBA from Stanford Graduate School of Business, and an M.S. in Biotechnology from Johns Hopkins University .
Past Roles
| Organization | Role | Tenure | Committees/Impact |
|---|---|---|---|
| Deerfield Management Company, L.P. | Partner; Chairman, Deerfield Institute | 2013–present | Focus on venture capital and structured biotech/pharma investments |
| Warburg Pincus LLC | Managing Director | 2000–2012 | Led firm’s biotech/pharma investment efforts |
| National Venture Capital Association | Executive Committee member; Chair, Medical Innovation & Competitiveness Coalition | Prior service | Led life sciences industry efforts |
| Biotechnology Industry Organization | Emerging Companies Section Board | Prior service | Industry governance role |
External Roles
| Organization | Role | Tenure | Notes |
|---|---|---|---|
| Larimar Therapeutics, Inc. | Director | Current | Public biotech board |
| ARS Pharmaceuticals, Inc. | Director | 2022–2023 | Public biotech board (past) |
| Proteon Therapeutics, Inc. | Director | 2017–2019 | Public biotech board (past) |
| AveXis, Inc. | Director | 2014–2017 | Public biotech board (past) |
| Nivalis Therapeutics, Inc. | Director | 2014–2016 | Public biotech board (past) |
| Spinal Muscular Atrophy Foundation | Director | Current | Non-profit |
| Columbia University Medical Center | Board of Advisors | Current | Non-profit |
Board Governance
- Independence: PHGE’s Board determined Mr. Leff is independent under NYSE American and SEC standards .
- Board structure: Independent Chairman (Dr. Russell Greig) and separate CEO (Jonathan Solomon) .
- Attendance: In FY2024 the Board held 22 meetings; each incumbent director attended at least 75% of Board and applicable committee meetings. Independent directors held six executive sessions in 2024, chaired by the Chairman .
- Committee memberships (FY2024):
- Compensation Committee: Member (Chair: Dr. Alan Moses); 2 meetings .
- Audit Committee: Not a member (Chair: Susan Blum); 6 meetings .
- Nominating & Corporate Governance Committee: Not a member; 2 meetings .
- Classified board: Leff is Class III; term expires 2026 .
Fixed Compensation
| Component | FY2024 Amount | Notes |
|---|---|---|
| Annual cash retainer (non-employee director) | $35,000 policy baseline | Paid quarterly |
| Committee membership fees | $5,000 (Compensation Committee member) policy | Committee member fees: Audit $7,500; Compensation $5,000; Nominating $4,000 |
| Committee chair fees | Not applicable | Chairs: Audit $15,000; Compensation $10,000; Nominating $8,000 |
| FY2024 cash actually paid | $31,869 | Cash amounts owed to Mr. Leff were paid to Deerfield Management Company LP |
| Reimbursements | Travel/lodging expenses reimbursed | Policy |
Mix analysis (FY2024): Cash $31,869 (≈59% of total $54,311); Option grant-date fair value $22,442 (≈41%) .
Performance Compensation
| Equity Instrument | FY2024 Grant | Grant-Date Fair Value | Vesting Schedule | Performance Metrics |
|---|---|---|---|---|
| Stock options (non-employee director annual award) | 26,400 options (newly appointed director) | $22,442 | 25% vests at 1-year anniversary; remaining vests in 12 equal quarterly installments, subject to service; policy applied in 2024 structure (new directors 26,400; continuing 17,600; Chair 35,200) | No performance conditions disclosed; time-based vesting only |
- Compensation consultant: Aon Solutions UK Limited engaged to advise the Compensation Committee (2023 option exchange/repricing; 2024 market data and LTIs). The Compensation Committee administers the Company’s clawback policy .
Other Directorships & Interlocks
| External Entity | Relationship to PHGE | Potential Interlock/Conflict Consideration |
|---|---|---|
| Deerfield Management-affiliated entities | >5% beneficial owners of PHGE; received warrants/preferred in transactions; Leff is an affiliate of Deerfield | Stockholder approvals referenced investors (including Deerfield) for conversions/exercises; Board notes Leff’s affiliation. This indicates a related-party context where a director is affiliated with a significant investor receiving securities in financings . |
| APT (transaction counterparty) | Pre-merger counterparty (Background of Acquisition) | On Jan 8, 2024, BiomX met with Jonathan Leff (investor and APT board member) to discuss potential transaction structure and financing participation by Deerfield and AMR Action Fund, reflecting Leff’s dual-role influence during deal formation . |
Expertise & Qualifications
- Capital markets and biotech/pharma investing leadership across Deerfield and Warburg Pincus; governance roles at NVCA and BIO; and public/private biotech board experience .
- Academic credentials in finance and biotechnology (Harvard AB; Stanford MBA; Johns Hopkins M.S. in Biotechnology) .
Equity Ownership
| Metric | Value | Notes |
|---|---|---|
| Shares beneficially owned (Aug 22, 2025) | 8,250 | Less than 1% of class; based on 26,554,887 shares outstanding . |
| Options granted (FY2024) | 26,400 | As a newly appointed director in 2024 . |
| Options exercisable/vested (as of Dec 31, 2024) | None within 60 days | Director option vesting reflected; aggregate vesting across board shown; Leff’s line indicates not vested/exercisable within 60 days . |
| Pledging/Hedging policies | Prohibited | Policy bans short sales, derivatives, margin accounts, and hedging/pledging; pre-clearance and blackout periods apply . |
Insider Trades (PHGE)
| Filing | Date | Summary |
|---|---|---|
| Form 3 (Initial Statement) | Mar 21, 2024 | Initial beneficial ownership disclosure on joining Board |
| Form 4 | Jul 15, 2024 | Statement of changes in beneficial ownership; XML filing references Leff |
| Form 4 | Apr 18, 2025 | Transaction filing; company IR link to PDF |
| Form 4/A (Amendment) | Apr 21, 2025 | Administrative correction to Table II Column 5 |
| Form 4 | 2025 (additional XML) | Additional changes in beneficial ownership filing |
Note: Specific share counts/prices for the above forms are available in the linked SEC filings. Anti-hedging/pledging policies are in force .
Governance Assessment
- Alignment and incentives:
- Director comp mixes cash ($31,869) and stock options ($22,442 FV) with time-based vesting—no disclosed performance metrics. Cash was remitted to Deerfield Management Company LP, reflecting his affiliation but common for partners whose service fees accrue to their firm .
- Independence and engagement:
- Board affirms independence; Leff served only on the Compensation Committee and met attendance thresholds; Board held 22 meetings in 2024 and independent directors had six executive sessions, supporting oversight rigor .
- Related-party/conflict context:
- Deerfield-affiliated financings (warrants/preferred) required shareholder approvals; proxies explicitly disclose Leff’s Deerfield affiliation. The acquisition background shows Leff’s role in transaction discussions as an investor/director of APT and facilitation of Deerfield/AMR financing—material for conflict monitoring and recusal expectations .
- Compensation Committee governance:
- Independent consultant (Aon) engaged; committee oversees clawback policy. 2023 option exchange/repricing under committee purview is a potential investor sensitivity point; no director-specific performance conditions disclosed for equity .
RED FLAGS
- Deerfield affiliation and receipt of director cash to Deerfield Management Company LP; Deerfield is a >5% holder participating in securities issuances—heightened conflict scrutiny warranted. Ensure robust recusal in votes impacting Deerfield securities .
- Option repricing/exchange (2023) under Compensation Committee oversight can be viewed unfavorably if not clearly justified by market-competitive rationale .
Signals supporting confidence
- Independent status affirmed; clear committee roles; consistent attendance; robust anti-hedging/pledging policy; independent consultant involvement in compensation decisions .