Form: 3

Initial statement of beneficial ownership of securities

September 26, 2018

Documents

FORM 3
 UNITED STATES SECURITIES AND EXCHANGE COMMISSION
Washington, D.C. 20549

INITIAL STATEMENT OF BENEFICIAL OWNERSHIP OF SECURITIES

Filed pursuant to Section 16(a) of the Securities Exchange Act of 1934 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 *
  Hallam Trevor
 2. Date of Event Requiring Statement (Month/Day/Year)
09/26/2018		 3. Issuer Name and Ticker or Trading Symbol
SUTRO BIOPHARMA INC [STRO]
(Last)
(First)
(Middle)
C/O SUTRO BIOPHARMA, INC., 310 UTAH AVENUE, SUITE 150		 4. Relationship of Reporting Person(s) to Issuer
(Check all applicable)
_____ Director _____ 10% Owner
__X__ Officer (give title below) _____ Other (specify below)
Chief Science Officer
 5. If Amendment, Date Original Filed(Month/Day/Year)
(Street)

SOUTH SAN FRANCISCO, CA 94080		 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 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 13,774
D
 

Reminder: Report on a separate line for each class of securities beneficially owned directly or indirectly. SEC 1473 (7-02)
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Table II - Derivative Securities Beneficially Owned (e.g., puts, calls, warrants, options, convertible securities)
1. Title of Derivative Security
(Instr. 4)		 2. Date Exercisable and Expiration Date
(Month/Day/Year)		 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)
Date Exercisable Expiration Date Title Amount or Number of Shares
Series D Shares   (1)   (1) Common Stock 50,033 $ (1) D  
Stock Option (right to buy Common Stock)   (2) 02/08/2021 Common Stock 33,116 $ 4.36 D  
Stock Option (right to buy Common Stock)   (2) 09/19/2022 Common Stock 19,405 $ 4.36 D  
Stock Option (right to buy Common Stock)   (2) 02/13/2023 Common Stock 6,343 $ 5.81 D  
Stock Option (right to buy Common Stock)   (2) 02/26/2024 Common Stock 24,783 $ 5.81 D  
Stock Option (right to buy Common Stock)   (3) 09/27/2025 Common Stock 17,910 $ 11.98 D  
Stock Option (right to buy Common Stock)   (2) 09/27/2025 Common Stock 15,426 $ 11.98 D  

Reporting Owners

Reporting Owner Name / Address Relationships
Director 10% Owner Officer Other
Hallam Trevor
C/O SUTRO BIOPHARMA, INC.
310 UTAH AVENUE, SUITE 150
SOUTH SAN FRANCISCO, CA 94080		       Chief Science Officer  

Signatures

/s/ Edward C. Albini as attorney-in-fact for Trevor Hallam 09/26/2018
**Signature of Reporting Person Date

Explanation of Responses:

* 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).
(1) Each share of the issuer's Series D Preferred Stock will automatically convert into 0.0405 share of the issuer's Common Stock immediately upon the closing of the issuer's initial public offering and has no expiration date.
(2) The option is fully vested.
(3) The option vests as to 2.0833% of the total shares monthly, beginning on October 15, 2015, with 100% of the total shares vested and exercisable on September 15, 2019, subject to the reporting person's provision of service to the issuer on each vesting date.

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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