CytomX (CTMX) reports 650,000 CBO stock options at $3.74

Rhea-AI Filing Summary

CytomX Therapeutics (CTMX) filed a Form 4 reporting a stock option grant to its Chief Business Officer, Rachael Lester. The award covers 650,000 options to buy common stock at an exercise price of $3.74 per share, granted on 10/20/2025.

Per the vesting terms, 25% of the shares vest on the one-year anniversary of October 20, 2025, with the remainder vesting in equal monthly installments so that the grant is fully vested on the fourth anniversary. The options expire on 10/19/2035. Ownership is reported as Direct (D).

Insider Trade Summary

1 transaction reported

Mixed 1 txn

Insider Lester Rachael

Role Chief Business Officer

Type	Security	Shares	Price	Value
Grant/Award	Stock Option (Right to Buy)	650,000	$0.00	--

Holdings After Transaction: Stock Option (Right to Buy) — 650,000 shares (Direct)

Footnotes (1)

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Form 4 Insider Transactions: What Each Field Means →

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

OMB Number:			3235-0287
Estimated average burden
hours per response:			0.5

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

Check this box to indicate that a transaction was made pursuant to a contract, instruction or written plan for the purchase or sale of equity securities of the issuer that is intended to satisfy the affirmative defense conditions of Rule 10b5-1(c). See Instruction 10.

1. Name and Address of Reporting Person^*

Lester Rachael

(Last) (First) (Middle)

C/O CYTOMX THERAPEUTICS, INC.

151 OYSTER POINT BLVD., SUITE 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 Business Officer

3. Date of Earliest Transaction (Month/Day/Year)
10/20/2025

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)	$3.74	10/20/2025		A		650,000		(1)	10/19/2035	Common Stock	650,000	$0	650,000	D

Explanation of Responses:

1. 25% of the shares subject to the option vest on the one year anniversary measured from October 20, 2025 (the "Vesting Commencement Date"), and 1/48th of the shares will vest monthly thereafter, 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.

	/s/ Christopher Ogden, as Attorney-in-Fact for Rachael Lester	10/29/2025
	** Signature of Reporting Person	Date
Reminder: Report on a separate line for each class of securities beneficially owned directly or indirectly.
* If the form is filed by more than one reporting person, see Instruction 4 (b)(v).
** Intentional misstatements or omissions of facts constitute Federal Criminal Violations See 18 U.S.C. 1001 and 15 U.S.C. 78ff(a).
Note: File three copies of this Form, one of which must be manually signed. If space is insufficient, see Instruction 6 for procedure.
Persons who respond to the collection of information contained in this form are not required to respond unless the form displays a currently valid OMB Number.

FAQ

What did CTMX report on this Form 4?

A stock option grant to Chief Business Officer Rachael Lester was reported.

How many options were granted and at what price?

The grant includes 650,000 stock options with an exercise price of $3.74 per share.

When was the option grant made?

The grant date is 10/20/2025.

What is the vesting schedule for the options?

25% vests on the one-year anniversary of October 20, 2025, then monthly thereafter until fully vested on the fourth anniversary.

When do the options expire?

The options expire on 10/19/2035.

How is ownership reported?

Ownership is reported as Direct (D).

What is the reporting person's role at CTMX?

The reporting person is the Chief Business Officer.