[Form 4] CytomX Therapeutics, Inc. Insider Trading Activity

Rhea-AI Filing Summary

CytomX Therapeutics insider grant to Chief Medical Officer

Yu-Waye Chu, Chief Medical Officer of CytomX Therapeutics, acquired equity awards on 09/26/2025 consisting of a stock option to purchase 87,500 shares of common stock at an exercise price of $2.90 and 43,750 Performance Stock Units (PSUs), each PSU representing one contingent share. The option vests monthly at 1/48th beginning on the Vesting Commencement Date of 09/26/2025 and becomes fully vested on the fourth anniversary if the reporting person remains in service. The PSUs vest in three tranches, with 1/3 vesting upon achievement of each of three specified clinical milestones, subject to continued service. All reported holdings are direct.

Insights

Financial Analyst

TL;DR: A routine executive equity grant: an 87,500-share option at $2.90 plus 43,750 PSUs aligns CMO incentives with clinical progress.

This equity grant combines time-based option vesting and milestone-based PSUs, linking compensation to both retention and specific clinical outcomes. The option's 1/48th monthly vesting over four years is standard for executive awards and supports retention. The PSUs vest only upon achievement of three clinical milestones, creating direct linkage between pay and program progress. Investors should note the exact quantities and exercise price disclosed; the transaction is a non-derivative acquisition reported as direct ownership.

Corporate Governance Expert

TL;DR: Grant structure reflects best practices by mixing time-based and milestone-based equity to align executive incentives with company goals.

The award packaging—time-vested options plus milestone PSUs—is a governance approach that balances retention with performance orientation, particularly appropriate for a clinical-stage biotech. Vesting conditions are explicit: monthly pro rata option vesting over four years and PSU vesting tied to three clinical milestones with service conditions. The Form 4 filing properly discloses the transaction details and direct beneficial ownership following the grant.

SEC Form 4

FORM 4

UNITED STATES SECURITIES AND EXCHANGE COMMISSION
Washington, D.C. 20549

STATEMENT OF CHANGES IN BENEFICIAL OWNERSHIP

Filed pursuant to Section 16(a) of the Securities Exchange Act of 1934
or Section 30(h) of the Investment Company Act of 1940

OMB APPROVAL

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Check this box if no longer subject to Section 16. Form 4 or Form 5 obligations may continue. See Instruction 1(b).

1. Name and Address of Reporting Person^*

Chu Yu-Waye

(Last) (First) (Middle)

C/O CYTOMX THERAPEUTICS, INC.

151 OYSTER POINT BLVD., STE. 400

(Street)

SOUTH SAN FRANCISCO CA 94080

(City) (State) (Zip)

2. Issuer Name and Ticker or Trading Symbol
CytomX Therapeutics, Inc. [ CTMX ]

5. Relationship of Reporting Person(s) to Issuer
(Check all applicable)

	Director		10% Owner
X	Officer (give title below)		Other (specify below)
	Chief Medical Officer

3. Date of Earliest Transaction (Month/Day/Year)
09/26/2025

4. If Amendment, Date of Original Filed (Month/Day/Year)

6. Individual or Joint/Group Filing (Check Applicable Line)

X	Form filed by One Reporting Person
	Form filed by More than One Reporting Person

Table I - Non-Derivative Securities Acquired, Disposed of, or Beneficially Owned
1. Title of Security (Instr. 3)	2. Transaction Date (Month/Day/Year)	2A. Deemed Execution Date, if any (Month/Day/Year)	3. Transaction Code (Instr. 8)		4. Securities Acquired (A) or Disposed Of (D) (Instr. 3, 4 and 5)			5. Amount of Securities Beneficially Owned Following Reported Transaction(s) (Instr. 3 and 4)	6. Ownership Form: Direct (D) or Indirect (I) (Instr. 4)	7. Nature of Indirect Beneficial Ownership (Instr. 4)
			Code	V	Amount	(A) or (D)	Price

Table II - Derivative Securities Acquired, Disposed of, or Beneficially Owned (e.g., puts, calls, warrants, options, convertible securities)
1. Title of Derivative Security (Instr. 3)	2. Conversion or Exercise Price of Derivative Security	3. Transaction Date (Month/Day/Year)	3A. Deemed Execution Date, if any (Month/Day/Year)	4. Transaction Code (Instr. 8)		5. Number of Derivative Securities Acquired (A) or Disposed of (D) (Instr. 3, 4 and 5)		6. Date Exercisable and Expiration Date (Month/Day/Year)		7. Title and Amount of Securities Underlying Derivative Security (Instr. 3 and 4)		8. Price of Derivative Security (Instr. 5)	9. Number of derivative Securities Beneficially Owned Following Reported Transaction(s) (Instr. 4)	10. Ownership Form: Direct (D) or Indirect (I) (Instr. 4)	11. Nature of Indirect Beneficial Ownership (Instr. 4)
				Code	V	(A)	(D)	Date Exercisable	Expiration Date	Title	Amount or Number of Shares
Stock Option (Right to Buy)	$2.9	09/26/2025		A		87,500		(1)	09/25/2035	Common Stock	87,500	$0	87,500	D
Performance Stock Units (PSUs)	(2)	09/26/2025		A		43,750		(2)	(2)	Common Stock	43,750	$0	43,750	D

Explanation of Responses:

1. 1/48th of the shares subject to the option vest on each monthly anniversary measured from September 26, 2025 (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.

2. 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.

	/s/ Christopher Ogden, as Attorney-in-Fact for Yu-Waye Chu	09/30/2025
	** Signature of Reporting Person	Date
Reminder: Report on a separate line for each class of securities beneficially owned directly or indirectly.
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