UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

WASHINGTON, DC 20549

SCHEDULE 13G

(Amendment No. 1)

UNDER THE SECURITIES EXCHANGE ACT OF 1934¹

Sutro Biopharma, Inc.

(Name of Issuer)

Common Stock, par value $0.001

(Title of Class of Securities)

869367102

(CUSIP Number)

December 31, 2020

(Date of Event Which Requires Filing of this Statement)

Check the appropriate box to designate the rule pursuant to which this Schedule is filed:

¨ Rule 13d-1(b)

x Rule 13d-1(c)

¨ Rule 13d-1(d)

¹ The remainder of this cover page shall be filled out for a reporting person’s initial filing on this form with respect to the subject class of securities, and for any subsequent amendment containing information which would alter the disclosures provided in a prior cover page.

The information required in the remainder of this cover page shall not be deemed to be “filed” for the purpose of Section 18 of the Securities Exchange Act of 1934 or otherwise subject to the liabilities of that section of the Act but shall be subject to all other provisions of the Act (however, see the Notes).

** SEE INSTRUCTIONS BEFORE FILLING OUT

** SEE INSTRUCTIONS BEFORE FILLING OUT

** SEE INSTRUCTIONS BEFORE FILLING OUT

Sutro Biopharma, Inc. (the “Company”).

The Company’s principal executive offices are located at 310 Utah Avenue, Suite 150, South San Francisco, California 94080.

This statement is filed on behalf of the following persons with respect to shares of common stock of the Company acquired by them (the “Shares”):

(i)       Ridgeback Capital Investments L.P., Delaware limited partnership (“RCILP”), with respect to Shares beneficially owned by it;

(ii)       Ridgeback Capital Investments LLC, a Delaware limited liability company (“RCI”), with respect to Shares beneficially owned by it; and

(iii)       Ridgeback Capital Management LLC, a Delaware limited liability company (“RCM”), with respect to Shares beneficially owned by it.

The foregoing persons are hereinafter referred to collectively as the “Reporting Persons.” Any disclosures herein with respect to persons other than the Reporting Persons are made on information and belief after making inquiry to the appropriate party.

The address of the principal business office of each of the Reporting Persons is 500 South Pointe Drive, Suite 220, Miami Beach, Florida 33139.

RCILP is a Cayman Island exempted limited partnership. RCI is a Delaware limited liability company. RCM is a Delaware limited liability company.

Common stock, par value $0.001 per share.

869367102

Item 3.

If this statement is filed pursuant to Rules 13d-1(b) or 13d- 2(b) or (c), check whether the person filing is a:

The percentages used herein are calculated based upon 44,992,978 shares of common stock outstanding, as reported in the Company’s final prospectus dated December 8, 2020 and filed with the SEC on December 12, 2020. As of the close of business on December 31, 2020, the Reporting Persons beneficially owned shares of the Company’s common stock in the amounts and percentages listed below:

RCM and RCI do not own any Shares directly. RCI is the general partner of RCILP. Pursuant to an investment management agreement, RCM maintains investment and voting power with respect to the securities held or controlled by RCI. Wayne Holman, an individual, controls RCM. By reason of the provisions of Rule 13d-3 of the Securities Exchange Act of 1934, as amended, RCM and RCI may be deemed to own beneficially all of the Shares (constituting approximately 2.5% of the shares outstanding). Each of RCM and RCI disclaim beneficial ownership of any of the securities covered by this statement, except to the extent of any pecuniary interest therein.

If this statement is being filed to report the fact that as of the date hereof the reporting person has ceased to be the beneficial owner of more than five percent of the class of securities, check the following. ⌧

To the knowledge of the Reporting Persons, no other person has the right to receive or the power to direct the receipt of dividends from, or the proceeds from the sale of, a number of the Shares which represents more than five percent of the number of outstanding shares of the Shares.

Not Applicable.

Not Applicable.

Not Applicable.

Each of the Reporting Persons hereby makes the following certification:

By signing below I certify that, to the best of my knowledge and belief, the securities referred to above were not acquired and are not held for the purpose of or with the effect of changing or influencing the control of the issuer of the securities and were not acquired and are not held in connection with or as a participant in any transaction having that purpose or effect.

SIGNATURE

After reasonable inquiry and to the best of my knowledge and belief, I certify that the information set forth in this statement is true, complete and correct.

DATED: February 16, 2021

EXHIBIT INDEX

____________________

*Previously filed.