Initial Statement of Beneficial Ownership (3)

FORM 3	UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 INITIAL STATEMENT OF BENEFICIAL OWNERSHIP OF SECURITIES	OMB APPROVAL OMB Number: 3235-0104 Estimated average burden hours per response... 0.5
	Filed pursuant to Section 16(a) of the Securities Exchange Act of 1934 or Section 30(h) of the Investment Company Act of 1940

1. Name and Address of Reporting Person ^*

RAY DEBANJAN

2. Date of Event Requiring Statement (MM/DD/YYYY) 5/15/2017

3. Issuer Name and Ticker or Trading Symbol

CytomX Therapeutics, Inc. [CTMX]

(Last) (First) (Middle)

C/O CYTOMX THERAPEUTICS, INC., 151 OYSTER POINT BLVD., SUITE 400

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

_____ Director _____ 10% Owner
___ X ___ Officer (give title below) _____ Other (specify below)
Chief Financial Officer /

(Street)

SOUTH SAN FRANCISCO, CA 94080

(City) (State) (Zip)

5. If Amendment, Date Original Filed (MM/DD/YYYY)

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 Beneficially Owned
1.Title of Security (Instr. 4)	2. Amount of Securities Beneficially Owned (Instr. 4)	3. Ownership Form: Direct (D) or Indirect (I) (Instr. 5)	4. Nature of Indirect Beneficial Ownership (Instr. 5)
Common Stock	21928	D

*Table II - Derivative Securities Beneficially Owned ( e.g.* , puts, calls, warrants, options, convertible securities)**
1. Title of Derivate Security (Instr. 4)	2. Date Exercisable and Expiration Date (MM/DD/YYYY)		3. Title and Amount of Securities Underlying Derivative Security (Instr. 4)		4. Conversion or Exercise Price of Derivative Security	5. Ownership Form of Derivative Security: Direct (D) or Indirect (I) (Instr. 5)	6. Nature of Indirect Beneficial Ownership (Instr. 5)
1. Title of Derivate Security (Instr. 4)	Date Exercisable	Expiration Date	Title	Amount or Number of Shares	4. Conversion or Exercise Price of Derivative Security		6. Nature of Indirect Beneficial Ownership (Instr. 5)
Stock Option (Right to Buy)	⁽¹⁾	9/13/2021	Common Stock	34485	$1.1339	D
Stock Option (Right to Buy)	⁽²⁾	12/10/2023	Common Stock	33225	$1.2599	D
Stock Option (Right to Buy)	⁽³⁾	2/27/2024	Common Stock	19510	$1.4489	D
Stock Option (Right to Buy)	⁽⁴⁾	5/6/2025	Common Stock	30640	$4.4728	D
Stock Option (Right to Buy)	⁽⁵⁾	7/20/2025	Common Stock	85938	$6.6147	D
Stock Option (Right to Buy)	⁽⁶⁾	8/25/2025	Common Stock	41090	$6.6147	D
Stock Option (Right to Buy)	⁽⁷⁾	1/20/2026	Common Stock	45000	$14.46	D
Stock Option (Right to Buy)	⁽⁸⁾	1/24/2027	Common Stock	97500	$11.94	D
Stock Option (Right to Buy)	⁽⁹⁾	5/12/2027	Common Stock	30000	$14.62	D

Explanation of Responses:
(1)	100% of the shares subject to the option are fully vested and exercisable.
(2)	This option vests in 48 substantially equal monthly installments starting on July 31, 2013, with each additional installment vesting on the last day of each month thereafter, subject to the Reporting Person's continued service to the Issuer through each such date.
(3)	This option vests in 48 substantially equal monthly installments starting on February 28, 2014, with each additional installment vesting on the last day of each month thereafter, subject to the Reporting Person's continued service to the Issuer through each such date.
(4)	This option vests in 48 substantially equal monthly installments starting on January 31, 2015, with each additional installment vesting on the last day of each month thereafter, subject to the Reporting Person's continued service to the Issuer through each such date.
(5)	This option vests in 48 substantially equal monthly installments starting on July 1, 2015, with each additional installment vesting on the last day of each month thereafter, subject to the Reporting Person's continued service to the Issuer through each such date.
(6)	This option vests in 48 substantially equal monthly installments starting on August 28, 2015, with each additional installment vesting on the last day of each month thereafter, subject to the Reporting Person's continued service to the Issuer through each such date.
(7)	1/48th of the shares subject to the option vest on each monthly anniversary measured from January 1, 2016 (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.
(8)	1/48th of the shares subject to the option vest on each monthly anniversary measured from January 1, 2017 (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.
(9)	This option vests in 48 substantially equal monthly installments starting on May 15, 2017, subject to the Reporting Person's continued service to the Issuer through each such date.

Reporting Owners
Reporting Owner Name / Address	Relationships
Reporting Owner Name / Address	Director	10% Owner	Officer	Other
RAY DEBANJAN C/O CYTOMX THERAPEUTICS, INC. 151 OYSTER POINT BLVD., SUITE 400 SOUTH SAN FRANCISCO, CA 94080			Chief Financial Officer

Signatures
/s/ Cynthia J. Ladd, as Attorney-in-Fact for Debanjan Ray		5/18/2017
^** 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 5(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.
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