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James Kastenmayer

General Counsel and Secretary at ArriVent BioPharma
Executive

About James Kastenmayer

James P. Kastenmayer, J.D., Ph.D., is General Counsel and Secretary of ArriVent BioPharma (AVBP) since September 2023; age 53 as of April 28, 2025, with a background spanning Aeglea BioTherapeutics (GC/Corp Sec; interim CEO), Viela Bio (GC, advised FDA approval and launch of Uplizna and Horizon acquisition), AstraZeneca (global legal director and senior patent director), MedImmune (IP counsel), and early-career IP boutique experience . He holds a J.D. from Georgetown University Law Center, a Ph.D. in biochemistry and cell and molecular biology from Michigan State University, and a B.A. in biology from the University of Virginia; he is a registered patent attorney . Company-level TSR, revenue growth, and EBITDA growth are not disclosed in relation to his tenure in the reviewed filings.

Past Roles

OrganizationRoleYearsStrategic Impact
Aeglea BioTherapeutics, Inc.General Counsel & Corporate Secretary; Interim CEOJul 2021–Mar 2023; Interim CEO Aug–Nov 2022 Led legal/compliance; interim stewardship during CEO transition
Viela Bio, Inc.General CounselJan 2020–Mar 2021 Advised FDA approval and launch of Uplizna; advised on acquisition by Horizon Therapeutics plc
AstraZenecaGlobal Legal Director; Senior Patent DirectorMay 2012–Dec 2019 Advised commercialization and market access strategies, collaborations, legal proceedings; accountable for global IP estates
MedImmuneIP CounselEarlier career IP portfolio development and protection
IP boutique firmAssociateEarlier career IP litigation/prosecution experience

External Roles

OrganizationRoleYearsStrategic Impact
Not disclosedNo external public company directorships disclosed in reviewed filings

Fixed Compensation

ItemFiscal Year/DateAmount/Terms
Base SalaryOffer letter; start scheduled Sep 5, 2023$400,000 annualized (paid $16,666.67 semi-monthly)
Target Bonus %Offer letter40% of base; actual awards at company discretion; payable by Mar 15 following year; contingent on continued employment at payout
Employment StatusOngoingAt-will employment; terms may be changed by the company

Performance Compensation

Award TypeGrant/EligibilityUnits/ValueStrike/ExpirationVesting
Stock Options (eligibility at hire)Following satisfaction of employment conditions and Board approvalEligible to receive option to purchase 1,000,000 shares at FMV on grant date (subject to award agreement and plan) Not disclosed for individual grantCompany option awards generally vest 25% on first anniversary, then monthly over 36 months under the Plans
Equity Plan Framework2021 Plan; 2024 PlanPlans authorize stock options, RSUs, restricted stock, other stock-based awards Plan expirations: 2021 Plan expires June 9, 2031; 2024 Plan Oct 12, 2033 Standard vesting per plan for options (25% + 36 monthly installments)

Notes:

  • Filings do not disclose James Kastenmayer’s specific option grant date, strike price, or expiration; vesting reflects plan-wide terms .

Equity Ownership & Alignment

As-of DateCommon Shares OwnedOptions Exercisable or Vesting within 60 daysHedging/Pledging Policy
April 21, 20257,386 shares 40,409 shares underlying options Insider trading policy prohibits short sales, margin accounts, pledging, and transactions involving puts/calls/straddles/collars; pre-clearance by General Counsel required for directors/senior management

Additional governance/trading controls:

  • Rule 10b5-1 trading plan policy with cooling-off periods (90–120 days for officers/directors) and one-plan limits; GC acknowledgment required before plan effectiveness .

Employment Terms

TermStatus/Details
Role & StartGeneral Counsel & Secretary since September 2023
Employment AgreementCompany states executive officers have employment agreements; all are at-will
Severance/Change-in-ControlExecutive Severance Plan described for named executive officers and CFO: 1.25× base + pro-rated target bonus (non-CIC) for certain roles; 1.5× or 2× base + target bonus (CIC) depending on role; full equity acceleration on CIC termination; COBRA and outplacement included . Filings do not explicitly list the General Counsel as a Severance Plan participant; eligibility defined by title in Exhibit A (not reproduced) .
Clawbacks/Ownership GuidelinesNo executive clawback or stock ownership multiple-of-salary guidelines disclosed in reviewed filings; insider trading policy governs conduct
BenefitsEligible for standard employee benefit programs; company 401(k) match: 100% of salary deferrals up to 4% of pay per payroll period

Investment Implications

  • Alignment: Modest direct share ownership (7,386 shares) and a pool of options exercisable/vesting within 60 days (40,409 shares) tie compensation to equity value; prohibition on hedging/pledging strengthens alignment and reduces adverse trading behaviors .
  • Selling pressure and liquidity: Near-term vesting/exercisable options increase potential tradable float, though trades are constrained by blackouts, pre-clearance, and 10b5-1 cooling-off rules; as General Counsel, policy requires GC pre-clearance for covered persons’ transactions .
  • Retention and severance: At-will status and lack of explicit Severance Plan participation disclosure for the General Counsel reduce visibility into change-of-control economics; by contrast, named executive officers and the CFO have defined severance/CIC terms including equity acceleration, which can influence retention dynamics across the leadership team .
  • Execution track record: Prior legal leadership through an FDA approval and product launch (Uplizna) and corporate acquisition at Viela, plus broad IP/commercial legal stewardship at AstraZeneca/MedImmune, indicate strong regulatory, IP, and transaction execution experience in biopharma contexts .