# EDGAR Filing Document

**Accession Number:** 0001872398
**File Stem:** 0001872398-26-000002
**Filing Date:** 2026-3
**Character Count:** 7971
**Document Hash:** 09bf0dce5ee10f067b7128e04b6876f1
**Contains OCR:** False
**Source Format:** 

## Filing Content

## Filing Summary
**0001872398-26-000002.hdr.sgml**: 20260303

**ACCESSION NUMBER**: 0001872398-26-000002

**CONFORMED SUBMISSION TYPE**: 4

**PUBLIC DOCUMENT COUNT**: 1

**CONFORMED PERIOD OF REPORT**: 20260301

**FILED AS OF DATE**: 20260303

**DATE AS OF CHANGE**: 20260303

**REPORTING-OWNER**: 

**OWNER DATA:**
- **COMPANY CONFORMED NAME:** Chung Jane
- **CENTRAL INDEX KEY:** 0001872398

**ORGANIZATION NAME:**

**FILING VALUES:**
- **FORM TYPE:** 4
- **SEC ACT:** 1934 Act
- **SEC FILE NUMBER:** 001-38662
- **FILM NUMBER:** 26717637

**MAIL ADDRESS:**
- **STREET 1:** C/O SUTRO BIOPHARMA, INC.
- **STREET 2:** 310 UTAH AVE., SUITE 150
- **CITY:** SOUTH SAN FRANCISCO
- **STATE:** CA
- **ZIP:** 94080
**ISSUER**: 

**COMPANY DATA:**
- **COMPANY CONFORMED NAME:** SUTRO BIOPHARMA, INC.
- **CENTRAL INDEX KEY:** 0001382101
- **STANDARD INDUSTRIAL CLASSIFICATION:** BIOLOGICAL PRODUCTS (NO DIAGNOSTIC SUBSTANCES) [2836]
- **ORGANIZATION NAME:** 03 Life Sciences
- **EIN:** 452441988
- **FISCAL YEAR END:** 1231

**BUSINESS ADDRESS:**
- **STREET 1:** 111 OYSTER POINT BLVD.
- **CITY:** SOUTH SAN FRANCISCO
- **STATE:** CA
- **ZIP:** 94080
- **BUSINESS PHONE:** 650-392-8412

**MAIL ADDRESS:**
- **STREET 1:** 111 OYSTER POINT BLVD.
- **CITY:** SOUTH SAN FRANCISCO
- **STATE:** CA
- **ZIP:** 94080

**FORMER COMPANY:**
- **FORMER CONFORMED NAME:** SUTRO BIOPHARMA INC
- **DATE OF NAME CHANGE:** 20061127

### UNITED STATES SECURITIES AND EXCHANGE COMMISSION
**Washington, D.C. 20549**

## FORM 4

### STATEMENT OF CHANGES IN BENEFICIAL OWNERSHIP

[ ] Check this box if no longer subject to Section 16. Form 4 or Form 5 obligations may continue. See Instruction 1(b).

[ ] Check this box to indicate that a transaction was made pursuant to a contract, instruction or written plan for the purchase or sale of equity securities of the issuer that is intended to satisfy the affirmative defense conditions of Rule 10b5-1(c). See Instruction 10.

---

| | | |
|:---|:---|:---|
| **1. Name and Address of Reporting Person**<sup>*</sup><br>Chung Jane<br><sub>(Last) (First) (Middle)</sub><br>C/O SUTRO BIOPHARMA, INC.<br>111 OYSTER POINT BLVD.<br><sub>(Street)</sub><br>SOUTH SAN FRANCISCO, CA 94080<br><sub>(City) (State) (Zip)</sub> | **3. Date of Earliest Transaction (Month/Day/Year)**<br>2026-03-01 | **5. Relationship of Reporting Person(s) to Issuer**<br>(Check all applicable)<br>[X] Director [ ] 10% Owner<br>[X] Officer (give title below) [ ] Other (specify below)<br>_Chief Executive Officer_ |
| **2. Issuer Name and Ticker or Trading Symbol**<br>SUTRO BIOPHARMA, INC. [ STRO ] | **4. If Amendment, Date of Original Filed (Month/Day/Year)**<br>  | **6. Individual or Joint/Group Filing (Check Applicable Line)**<br>[X] Form filed by One Reporting Person<br>[ ] Form filed by More than One Reporting Person |

---

## Table I - Non-Derivative Securities

---

|  |  |  |  |  |  |  |  |  |  |  |
| --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- |
| 1. Title of Security | 2. Transaction Date | 2A. Deemed Execution Date | 3. Transaction Code (V) | 3. Transaction Code (V) | 4. Securities Acquired (A) or Disposed of (D) | 4. Securities Acquired (A) or Disposed of (D) | 4. Securities Acquired (A) or Disposed of (D) | 5. Amount of Securities Beneficially Owned | 6. Ownership Form | 7. Nature of Indirect Beneficial Ownership |
| 1. Title of Security | 2. Transaction Date | 2A. Deemed Execution Date | Code | V | Amount | (A) or (D) | Price | 5. Amount of Securities Beneficially Owned | 6. Ownership Form | 7. Nature of Indirect Beneficial Ownership |
| Common Stock | 2026-03-01 |  | M |  | 688 | A | $0 | 14579 | D |  |
| Common Stock | 2026-03-01 |  | M |  | 2500 | A | $0 | 17079 | D |  |
| Common Stock | 2026-03-01 |  | F |  | 1271<sup>(1)</sup> | D | $20.47 | 15808 | D |  |
| Common Stock | 2026-03-02 |  | M |  | 7750 | A | $0 | 23558 | D |  |
| Common Stock | 2026-03-02 |  | F |  | 2779<sup>(1)</sup> | D | $20.55 | 20779 | D |  |

---

## Table II - Derivative Securities

---

|  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
| --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- |
| 1. Title of Derivative Security | 2. Conversion or Exercise Price | 3. Transaction Date | 3A. Deemed Execution Date | 4. Transaction Code (V) | 4. Transaction Code (V) | 5. Number of Derivative Securities Acquired (A) or Disposed of (D) | 5. Number of Derivative Securities Acquired (A) or Disposed of (D) | 6. Date Exercisable and Expiration Date | 6. Date Exercisable and Expiration Date | 7. Title and Amount of Underlying Securities | 7. Title and Amount of Underlying Securities | 8. Price of Derivative Security | 9. Number of Derivative Securities Beneficially Owned | 10. Ownership Form | 11. Nature of Indirect Beneficial Ownership |
| 1. Title of Derivative Security | 2. Conversion or Exercise Price | 3. Transaction Date | 3A. Deemed Execution Date | Code | V | (A) | (D) | Date Exercisable | Expiration Date | Title | Amount or Number of Shares | 8. Price of Derivative Security | 9. Number of Derivative Securities Beneficially Owned | 10. Ownership Form | 11. Nature of Indirect Beneficial Ownership |
| Restricted Stock Units (RSUs) | <sup>(2)</sup> | 2026-03-01 |  | M |  |  | 688 | <sup>(3)</sup> | 2027-03-01 | Common Stock | 688 | $0 | 688 | D |  |
| Restricted Stock Units (RSUs) | <sup>(2)</sup> | 2026-03-01 |  | M |  |  | 2500 | <sup>(4)</sup> | 2028-03-01 | Common Stock | 2500 | $0 | 5000 | D |  |
| Restricted Stock Units (RSUs) | <sup>(2)</sup> | 2026-03-02 |  | M |  |  | 7750 | <sup>(5)</sup> | 2029-03-02 | Common Stock | 7750 | $0 | 23250 | D |  |
| Restricted Stock Units (RSUs) | <sup>(2)</sup> | 2026-03-02 |  | A |  | 40000 |  | <sup>(6)</sup> | 2030-03-01 | Common Stock | 40000 | $0 | 40000 | D |  |
| Stock Option (right to buy) | $20.55 | 2026-03-02 |  | A |  | 175000 |  | <sup>(7)</sup> | 2036-03-02 | Common Stock | 175000 | $0 | 175000 | D |  |

---

### Footnotes:

(1) Represents the number of shares of Common Stock that have been withheld by the Issuer to satisfy its income tax withholding and remittance obligations in connection with the net settlement of restricted stock units; does not represent a sale by the reporting person.

(2) Each RSU represents a contingent right to receive one (1) share of the Issuer's Common Stock upon settlement.

(3) The RSUs vested or vest as to 1/4 of the total award annually, with the first tranche vested on March 1, 2024, subject to continued service through each vesting date.

(4) The RSUs vested or vest as to 1/4 of the total award annually, with the first tranche vested on March 1, 2025, subject to continued service through each vesting date.

(5) The RSUs vested or vest as to 1/4 of the total award annually, with the first tranche vested on March 2, 2026, subject to continued service through each vesting date.

(6) The RSUs shall vest as to 1/4 of the total award annually, with the first tranche vesting on March 1, 2027, subject to continued service through each vesting date.

(7) 1/48 of the total option award shall vest monthly, subject to the reporting person's continued service through each vesting date, with the first tranche vesting on April 1, 2026.

**Signature:** /s/ David Pauling as attorney-in-fact  
**Date:** 2026-03-03

### Remarks:

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).

** 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.

**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 Number.**