Ownership Submission

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 or Section 30(h) of the Investment Company Act of 1940

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3235-0287

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(Print or Type Responses)

1. Name and Address of Reporting Person ^*

Alta Partners VIII, L.P.

2. Issuer Name and Ticker or Trading Symbol
SUTRO BIOPHARMA INC [STRO]

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

_____ Director	__X__ 10% Owner
_____ Officer (give title below)	_____ Other (specify below)

(Last)

(First)

(Middle)

ONE EMBARCADERO CENTER, SUITE 3700

3. Date of Earliest Transaction (Month/Day/Year)
10/01/2018

(Street)

SAN FRANCISCO, CA 94111

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

6. Individual or Joint/Group Filing(Check Applicable Line)
___ Form filed by One Reporting Person
_X_ 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)
1.Title of Security (Instr. 3)	2. Transaction Date (Month/Day/Year)	2A. Deemed Execution Date, if any (Month/Day/Year)	Code	V	Amount	(A) or (D)	Price		6. Ownership Form: Direct (D) or Indirect (I) (Instr. 4)	7. Nature of Indirect Beneficial Ownership (Instr. 4)
Common Stock	10/01/2018		C		589,661	A	⁽¹⁾	589,661	D ⁽²⁾
Common Stock	10/01/2018		C		458,331	A	⁽³⁾	1,047,992	D ⁽²⁾
Common Stock	10/01/2018		C		382,698	A	⁽⁴⁾	1,430,690	D ⁽²⁾
Common Stock	10/01/2018		C		514,211	A	⁽⁵⁾	1,944,901	D ⁽²⁾

Reminder: Report on a separate line for each class of securities beneficially owned directly or indirectly.
	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 control number.		SEC 1474 (9-02)

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

(A)

(D)

Date Exercisable

Expiration Date

Title

Amount or Number of Shares

Series B Preferred Stock

⁽¹⁾

10/01/2018

10,201,769

⁽¹⁾

Common Stock

589,661

$ 0

D ⁽²⁾

Series C Preferred Stock

⁽³⁾

10/01/2018

12,387,324

⁽³⁾

Common Stock

458,331

$ 0

D ⁽²⁾

Series D Preferred Stock

⁽⁴⁾

10/01/2018

9,449,318

⁽⁴⁾

Common Stock

382,698

$ 0

D ⁽²⁾

Series E Preferred Stock

⁽⁵⁾

10/01/2018

18,698,578

⁽⁵⁾

Common Stock

514,211

$ 0

D ⁽²⁾

Reporting Owners

Reporting Owner Name / Address	Relationships
Reporting Owner Name / Address	Director	10% Owner	Officer	Other
Alta Partners VIII, L.P. ONE EMBARCADERO CENTER, SUITE 3700 SAN FRANCISCO, CA 94111		X
Alta Partners Management VIII, LLC ONE EMBARCADERO CENTER, SUITE 3700 SAN FRANCISCO, CA 94111		X
CHAMPSI FARAH ONE EMBARCADERO CENTER, SUITE 3700 SAN FRANCISCO, CA 94111		X
JANNEY DANIEL ONE EMBARCADERO CENTER, SUITE 3700 SAN FRANCISCO, CA 94111	X	X
NOHRA GUY P ONE EMBARCADERO CENTER, SUITE 3700 SAN FRANCISCO, CA 94111		X

Signatures

/s/ Daniel Janney as Managing Director of Alta Partners Management VIII, LLC, the general partner of Alta Partners VIII, L.P.		10/01/2018
^**Signature of Reporting Person		Date
/s/ Daniel Janney as Managing Director of Alta Partners Management VIII, LLC		10/01/2018
^**Signature of Reporting Person		Date
/s/ Farah Champsi		10/01/2018
^**Signature of Reporting Person		Date
/s/ Daniel Janney		10/01/2018
^**Signature of Reporting Person		Date
/s/ Guy Nohra		10/01/2018
^**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)	Each share of the issuer's Series B Preferred Stock automatically converted into 0.0578 share of the issuer's Common Stock on October 1, 2018 in connection with the closing of the issuer's sale of its Common Stock in its firm commitment initial public offering (the "IPO") pursuant to a registration statement on Form S-1 (File No. 333-227103) under the Securities Act of 1933, as amended (the "Registration Statement"), and had no expiration date.
(2)	The shares directly held by Alta Partners VIII, L.P. ("Alta VIII") are indirectly held by Alta Partners Management VIII, LLC ("Alta Management VIII"), which is the general partner of Alta VIII. The individual managing directors of Alta Management VIII are Farah Champsi, Guy Nohra and Daniel Janney. The managing directors of Alta Management VIII exercise sole voting and investment control with respect to the shares held by Alta VIII. The individual managing directors of Alta Management VIII disclaim beneficial ownership of all shares held by Alta VIII, except to the extent of their pecuniary interests therein.
(3)	Each share of the issuer's Series C Preferred Stock automatically converted into 0.0370 share of the issuer's Common Stock on October 1, 2018 in connection with the closing of the issuer's sale of its Common Stock in its IPO pursuant to the Registration Statement, and had no expiration date.
(4)	Each share of the issuer's Series D Preferred Stock automatically converted into 0.0405 share of the issuer's Common Stock on October 1, 2018 in connection with the closing of the issuer's sale of its Common Stock in its IPO pursuant to the Registration Statement, and had no expiration date.
(5)	Each share of the issuer's Series E Preferred Stock automatically converted into 0.0275 share of the issuer's Common Stock on October 1, 2018 in connection with the closing of the issuer's sale of its Common Stock in its IPO pursuant to the Registration Statement, and had no expiration date.

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