FORM 4
Check this box if no longer subject to Section 16. Form 4 or Form 5 obligations may continue. See Instruction 1(b).
UNITED STATES SECURITIES AND EXCHANGE COMMISSION
Washington, D.C. 20549

STATEMENT OF CHANGES IN BENEFICIAL OWNERSHIP OF SECURITIES

Filed pursuant to Section 16(a) of the Securities Exchange Act of 1934, Section 17(a) of the Public Utility Holding Company Act of 1935 or Section 30(h) of the Investment Company Act of 1940
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(Print or Type Responses)
1. Name and Address of Reporting Person *
Landau Jeffrey B
  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
(Last)
(First)
(Middle)
C/O CYTOMX THERAPEUTICS, INC., 151 OYSTER POINT BLVD., SUITE 400
3. Date of Earliest Transaction (Month/Day/Year)
07/19/2022
(Street)

SOUTH SAN FRANCISCO, CA 94080
4. If Amendment, Date 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
(City)
(State)
(Zip)
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
Common Stock               4,500 I Fidelity Traditional IRA
Common Stock               3,180 I Schwab ROTH IRA
Common Stock 07/19/2022   A(1)   11,250 A $ 0 34,931 (2) (3) D  
Common Stock 07/20/2022   S(4)   4,206 D $ 1.4222 30,725 (2) D  

Reminder: Report on a separate line for each class of securities beneficially owned directly or indirectly.
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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 Underlying Securities
(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 of Derivative Security: 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

Reporting Owners

Reporting Owner Name / Address Relationships
 Director  10% Owner  Officer  Other
Landau Jeffrey B
C/O CYTOMX THERAPEUTICS, INC.
151 OYSTER POINT BLVD., SUITE 400
SOUTH SAN FRANCISCO, CA 94080
      Chief Business Officer  

Signatures

 /s/ Lloyd Rowland, as Attorney-in-Fact for Jeffrey B Landau   07/21/2022
**Signature of Reporting Person Date

Explanation of Responses:

* 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).
(1) Represents Performance Stock Units ("PSUs") initially granted on October 24, 2021 that were subject to a performance-based vesting condition. The first milestone vesting condition was determined to be satisfied upon which 50% of the PSUs vested.
(2) Includes 16,274 restricted stock units.
(3) Reflects the adjusted total which includes the purchase of 5,040 shares under the Cytomx Therapeutics Employee Stock Purchase Plan on May 31, 2022.
(4) The shares were sold solely to satisfy tax or other government withholding obligations in connection with the vesting of shares subject to a PSU of the Issuer.

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