Sec Form 3 Filing - SVLSF V, LLC @ SUTRO BIOPHARMA INC - 2018-09-26

FORM 3 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 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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1. Name and Address of Reporting Person SVLSF V, LLC 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 BOSTON PLACE, 201 WASHINGTON ST., STE 3900 3. Date of Earliest Transaction (MM/DD/YY) 09/26/2018 (Street) BOSTON, MA02108 4. If Amendment, Date Original Filed (MM/DD/YY) 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 (MM/DD/YY) 2A. Deemed Execution Date, if any (MM/DD/YY) 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 (MM/DD/YY) 3A. Deemed Execution Date, if any (MM/DD/YY) 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 (MM/DD/YY) 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 Series A Preferred Stock ( 1 ) ( 1 ) ( 1 ) Common Stock 21,776 I By International Life Sciences Fund III Co-Investment, L.P. ( 2 ) Series B Preferred Stock ( 3 ) ( 3 ) ( 3 ) Common Stock 131,683 I By International Life Sciences Fund III Co-Investment, L.P. ( 2 ) Series C Preferred Stock ( 4 ) ( 4 ) ( 4 ) Common Stock 58,632 I By International Life Sciences Fund III Co-Investment, L.P. ( 2 ) Series C Preferred Stock Warrant (right to buy) $ 0.4797 ( 6 ) ( 5 ) ( 5 ) Series C Preferred Stock 11,544 I By International Life Sciences Fund III Co-Investment, L.P. ( 2 ) Series A Preferred Stock ( 1 ) ( 1 ) ( 1 ) Common Stock 1,835,270 I By International Life Sciences Fund III (LP1), L.P. ( 2 ) Series B Preferred Stock ( 3 ) ( 3 ) ( 3 ) Common Stock 11,097,596 I By International Life Sciences Fund III (LP1), L.P. ( 2 ) Series C Preferred Stock ( 4 ) ( 4 ) ( 4 ) Common Stock 4,941,391 I By International Life Sciences Fund III (LP1), L.P. ( 2 ) Series C Preferred Stock Warrant (right to buy) $ 0.4797 ( 6 ) ( 5 ) ( 5 ) Series C Preferred Stock 973,028 I By International Life Sciences Fund III (LP1), L.P. ( 2 ) Series A Preferred Stock ( 1 ) ( 1 ) ( 1 ) Common Stock 17,533 I By International Life Sciences Fund III Strategic Partners, L.P. ( 2 ) Series B Preferred Stock ( 3 ) ( 3 ) ( 3 ) Common Stock 106,019 I By International Life Sciences Fund III Strategic Partners, L.P. ( 2 ) Series C Preferred Stock ( 4 ) ( 4 ) ( 4 ) Common Stock 47,205 I By International Life Sciences Fund III Strategic Partners, L.P. ( 2 ) Series C Preferred Stock Warrant (right to buy) $ 0.4797 ( 6 ) ( 5 ) ( 5 ) Series C Preferred Stock 9,293 I By International Life Sciences Fund III Strategic Partners, L.P. ( 2 ) Series C Preferred Stock ( 4 ) ( 4 ) ( 4 ) Common Stock 9,217,015 I By SV Life Sciences Fund V, L.P. ( 7 ) Series D Preferred Stock ( 8 ) ( 8 ) ( 8 ) Common Stock 6,683,697 I By SV Life Sciences Fund V, L.P. ( 7 ) Series E Preferred Stock ( 9 ) ( 9 ) ( 9 ) Common Stock 9,155,794 I By SV Life Sciences Fund V, L.P. ( 7 ) Series C Preferred Stock ( 4 ) ( 4 ) ( 4 ) Common Stock 194,786 I By SV Life Sciences Fund V Strategic Partners, L.P. ( 10 ) Series D Preferred Stock ( 8 ) ( 8 ) ( 8 ) Common Stock 141,249 I By SV Life Sciences Fund V Strategic Partners, L.P. ( 10 ) Series E Preferred Stock ( 9 ) ( 9 ) ( 9 ) Common Stock 193,492 I By SV Life Sciences Fund V Strategic Partners, L.P. ( 10 )

Reporting Owners Reporting Owner Name / Address Relationships Director 10% Owner Officer Other SVLSF V, LLC ONE BOSTON PLACE 201 WASHINGTON ST., STE 3900 BOSTON, MA02108 X ILSF III, LLC ONE BOSTON PLACE 201 WASHINGTON ST., STE 3900 BOSTON, MA02108 X INTERNATIONAL LIFE SCIENCES FUND III (GP), L.P. ONE BOSTON PLACE 201 WASHINGTON ST., STE 3900 BOSTON, MA02108 X INTERNATIONAL LIFE SCIENCES FUND III CO-INVESTMENT, L.P. ONE BOSTON PLACE 201 WASHINGTON ST., STE 3900 BOSTON, MA02108 X INTERNATIONAL LIFE SCIENCES FUND III (LP1), L.P. ONE BOSTON PLACE 201 WASHINGTON ST., STE 3900 BOSTON, MA02108 X INTERNATIONAL LIFE SCIENCES FUND III STRATEGIC PARTNERS, L.P. ONE BOSTON PLACE 201 WASHINGTON ST., STE 3900 BOSTON, MA02108 X SV Life Sciences Fund V (GP), LP ONE BOSTON PLACE 201 WASHINGTON ST., STE 3900 BOSTON, MA02108 X SV LIFE SCIENCES FUND V LP ONE BOSTON PLACE 201 WASHINGTON ST., STE 3900 BOSTON, MA02108 X SV Life Sciences Fund V Strategic Partners, L.P. ONE BOSTON PLACE 201 WASHINGTON ST., STE 3900 BOSTON, MA02108 X Signatures /s/ Brent Faduski as authorized officer of SVLSF V, LLC 09/26/2018 Signature of Reporting Person Date /s/ Brent Faduski as authorized officer of ILSF III, LLC 09/26/2018 Signature of Reporting Person Date /s/ Brent Faduski as authorized officer of ILSF III, LLC, the GP of International Life Sciences Fund III (GP), L.P. 09/26/2018 Signature of Reporting Person Date /s/ Brent Faduski as authorized officer of ILSF III, LLC, the GP of International Life Sciences Fund III (GP), L.P., the GP of International Life Sciences Fund III Co-Investment, L.P. 09/26/2018 Signature of Reporting Person Date /s/ Brent Faduski as authorized officer of ILSF III, LLC, the GP of International Life Sciences Fund III (GP), L.P., the GP of International Life Sciences Fund III (LP1), L.P. 09/26/2018 Signature of Reporting Person Date /s/ Brent Faduski as authorized officer of ILSF III, LLC, the GP of International Life Sciences Fund III (GP), L.P., the GP of International Life Sciences Fund III Strategic Partners, L.P. 09/26/2018 Signature of Reporting Person Date /s/ Brent Faduski as authorized officer of SVLSF V , LLC, the GP of SV Life Sciences Fund V (GP), L.P. 09/26/2018 Signature of Reporting Person Date /s/ Brent Faduski as authorized officer of SVLSF V, LLC, the GP of SV Life Sciences Fund V (GP), L.P., the GP of SV Life Sciences Fund V, L.P. 09/26/2018 Signature of Reporting Person Date /s/ Brent Faduski as authorized officer of SVLSF V, LLC, the GP of SV Life Sciences Fund V (GP), L.P, the GP of SV Life Sciences Fund V Strategic Partners, L.P. 09/26/2018 Signature of Reporting Person Date

Explanation of Responses:

( 1 )Each share of the issuer's Series A Preferred Stock will automatically convert into 0.0433 share of the issuer's Common Stock immediately upon the closing of the issuer's initial public offering ("IPO") and has no expiration date. ( 2 )International Life Sciences Fund III (GP), LP. ("Fund III GP") is the general partner of each of: (i) International Life Sciences Fund III (LP1), L.P. ("ILSF LP1"), (ii) International Life Sciences Fund III Co-Investment, L.P. ("ILSF Co-Invest") and (iii) International Life Sciences Fund III Strategic Partners, L.P. ("ILSF Strategic" and collectively, the "Fund III Entities"). ILSF III, LLC (the "ILSF General Partner") is the general partner of Fund III GP and, through an investment committee comprised of James Garvey, Kate Bingham, Eugene D. Hill, III and Michael J. Ross controls voting and investment decisions over the Issuer's shares held by the Fund III Entities by majority vote. Each of Fund III GP, ILSF General Partner, and each member of the investment committee of ILSF General Partner disclaims beneficial ownership over the Shares held by the Fund III Entities except to the extent of any pecuniary interest therein. ( 3 )Each share of the issuer's Series B Preferred Stock will automatically convert into 0.0578 share of the issuer's Common Stock immediately upon the closing of the issuer's IPO and has no expiration date. ( 4 )Each share of the issuer's Series C Preferred Stock will automatically convert into 0.0370 share of the issuer's Common Stock immediately upon the closing of the issuer's IPO and has no expiration date. ( 5 )The warrant is exercisable at any time at the holder's election on a one-for one basis and automatically terminates on the completion of the issuer's initial public offering if not earlier exercised. ( 6 )The warrant has a net exercise provision under which the holder, in lieu of paying the exercise price in cash, can surrender the warrant and receive a net number of shares of preferred stock based on the fair market value of such stock at the time of exercise, after deducting the aggregate exercise price. ( 7 )These shares are owned directly by SV Life Sciences Fund V, L.P. ("SVLS V LP"). SV Life Sciences Fund V (GP), LP ("SVLS V GP") is the general partner of SVLS V LP. The general partner of SVLS V GP is SVLSF V, LLC. Kate Bingham, James Garvey, Eugene D. Hill, III and Michael J. Ross are members of the investment committee of SVLSF V, LLC. SVLS V GP, SVLSF V, LLC and each of the individuals comprising the SVLSF V, LLC investment committee may be deemed to share voting, dispositive and investment power over the shares held of record by SVLS V LP. Each of SVLS V GP, SVLSF V, LLC and the individual members of the SVLSF V, LLC investment committee disclaims beneficial ownership of these securities and this report shall not be deemed to be an admission that any one of them is the beneficial owner of such securities for purposes of Section 16 or any other purpose, except to the extent of their pecuniary interest therein. ( 8 )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 IPO and has no expiration date. ( 9 )Each share of the issuer's Series E Preferred Stock will automatically convert into 0.0275 share of the issuer's Common Stock immediately upon the closing of the issuer's IPO and has no expiration date. ( 10 )These shares are owned directly by SV Life Sciences Fund V Strategic Partners, L.P. ("SVLS V SPP"). SVLS V GP is the general partner of SVLS V SPP. The general partner of SVLS V GP is SVLSF V, LLC. Kate Bingham, James Garvey, Eugene D. Hill, III and Michael J. Ross are members of the investment committee of SVLSF V, LLC. SVLS V GP, SVLSF V, LLC and each of the individuals comprising the SVLSF V, LLC investment committee may be deemed to share voting, dispositive and investment power over the shares held of record by SVLS V SPP. Each of SVLS V GP, SVLSF V, LLC and the individual members of the SVLSF V, LLC investment committee disclaims beneficial ownership of these securities and this report shall not be deemed to be an admission that any one of them is the beneficial owner of such securities for purposes of Section 16 or any other purpose, except to the extent of their pecuniary interest therein.

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).

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