Rachael Lester - 02 Feb 2026 Form 4 Insider Report for CytomX Therapeutics, Inc. (CTMX)

Role: Chief Business Officer
Signature: /s/ Christopher Ogden, as Attorney-in-Fact for Rachael Lester
Issuer symbol: CTMX
Transactions as of: 02 Feb 2026
Net transactions value: $0
Form type: 4
Filing time: 04 Feb 2026, 16:28:36 UTC
Previous filing: 29 Oct 2025
SEC: View on sec.gov

Reporting Owners (1)

Name	Relationship	Address	Signature	Signature date	CIK
Lester Rachael	Chief Business Officer	C/O CYTOMX THERAPEUTICS, INC., 151 OYSTER POINT BLVD., SUITE 400, SOUTH SAN FRANCISCO	/s/ Christopher Ogden, as Attorney-in-Fact for Rachael Lester	04 Feb 2026	0002094324

Transactions Table

Type	Sym	Class	Transaction	Value $	Shares	Change %	* Price $	Shares After	Date	Ownership	Footnotes
transaction	CTMX	Common Stock	Award	$0	+20,000		$0.000000	20,000	02 Feb 2026	Direct	F1, F2

Derivative Securities (e.g., puts, calls, warrants, options, convertible securities)

Type	Sym	Class	Transaction	Value $	Shares	Change %	* Price $	Shares After	Date	Underlying Class	Amount	Exercise Price	Ownership	Footnotes
transaction	CTMX	Stock Option (Right to Buy)	Award	$0	+50,000		$0.000000	50,000	02 Feb 2026	Common Stock	50,000	$6.09	Direct	F3
transaction	CTMX	Performance Stock Units (PSUs)	Award	$0	+50,000		$0.000000	50,000	02 Feb 2026	Common Stock	50,000		Direct	F4

* An asterisk sign (*) next to the price indicates that the price is likely invalid.

Explanation of Responses:

Id	Content
F1	Constitute restricted stock units ("RSUs") for which the Reporting Person is entitled to receive one (1) share of Common Stock for each RSU upon vesting. 1/3rd of the RSUs vest annually on March 15 of each year, with the first 1/3rd vesting on March 15, 2027, subject to the Reporting Person continuing as a service provider through each such date.
F2	Includes 20,000 RSUs.
F3	1/48th of the shares subject to the option vest on each monthly anniversary measured from February 2, 2026 (the "Vesting Commencement Date"), such that 100% of the shares subject to the option will be fully vested and exercisable on the fourth anniversary of the Vesting Commencement Date, subject to the Reporting Person's continued service to the Issuer through each such date.
F4	Each Performance Stock Unit ("PSU") represents a contingent right to receive one (1) share of Common Stock upon vesting. 1/3 of the PSUs vest upon the achievement of each of three clinical milestones, subject to the Reporting Person continuing as a service provider through each such date.