Exhibit 99.1

Sutro Biopharma Reports Second Quarter 2022 Financial Results, Business Highlights and Anticipated Milestones

- Collaboration with Astellas on discovery and development of iADCs for up to three targets, includes an upfront payment of $90 million and $422.5 million in potential milestones per product candidate -

- A $10 million milestone payment from Merck was triggered upon first patient dosed in a Phase 1 study under the existing cytokine derivative collaboration -

- Discussions with FDA held mid-year 2022 signaled that the accelerated approval pathway could be available for STRO-002 in a platinum-resistant ovarian cancer patient population -

- Cash, cash equivalents and marketable securities totaled $191.6 million as of June 30, 2022, which, together with the $90 million upfront payment received from Astellas in July 2022, provides a projected cash runway into the first half of 2024, based on current business plans and assumptions –

SOUTH SAN FRANCISCO, Calif., August 8, 2022 – Sutro Biopharma, Inc. (Sutro or the Company) (NASDAQ: STRO), a clinical-stage oncology company pioneering site-specific and novel-format antibody drug conjugates (ADCs), today reported its financial results for the quarter ended June 30, 2022, its recent business highlights, and a preview of anticipated select milestones.

“This quarter, Sutro continued to execute on the promise of our platform, as marked by the recently announced collaboration with Astellas covering research and development of immunostimulatory ADCs, or iADCs—a novel modality with the potential to turn cold tumors hot,” said Bill Newell, Sutro’s Chief Executive Officer. “Additionally, we are pleased to see Merck dosing patients in its Phase 1 study as part of our cytokine derivative collaboration. This represents the sixth clinical-stage product candidate enabled by Sutro’s platform. Looking ahead, we are optimistic about the potential of our pipeline of ADCs; this includes STRO-002 for patients with platinum-resistant ovarian cancer, as well as our newly unveiled STRO-003, an optimized ROR1 ADC, which we anticipate will be our next proprietary product candidate to move into clinical studies.”

Recent Business Highlights and Anticipated Select Milestones

STRO-002, FolRα-Targeting ADC: STRO-002 is being studied in the clinic, in both the U.S. and Europe, for patients with ovarian and endometrial cancers.

STRO-001, CD74-Targeting ADC: The Phase 1 study for patients with B‑cell malignancies, including patients with non-Hodgkin's lymphoma (NHL) and multiple myeloma (MM), continues in dose escalation.

Additional Pipeline Programs: A Sutro Research Forum highlighted STRO-003 and its emerging research portfolio.

Collaboration Updates: Sutro continues to seek to maximize the value of its proprietary cell-free platform by working with partners on programs in multiple disease spaces and geographies and has generated from collaborators an aggregate of approximately $583 million, which includes payments and equity investments through June 30, 2022, in addition to the $90 million upfront payment from Astellas received in July 2022.

Second Quarter 2022 Financial Highlights

Cash, Cash Equivalents and Marketable Securities

As of June 30, 2022, Sutro had cash, cash equivalents and marketable securities of $191.6 million, as compared to $192.1 million as of March 31, 2022, which, together with the $90 million upfront payment received from Astellas in July 2022, provides a projected cash runway into the first half of 2024, based on current business plans and assumptions. The above balances do not include the value associated with Sutro’s holdings of Vaxcyte common stock.

Unrealized Loss from Decrease in Value of Vaxcyte Common Stock

As of June 30, 2022, Sutro held approximately 1.6 million shares of Vaxcyte common stock, with a fair value of $34.0 million. The non-operating, unrealized loss of $3.7 million in the second quarter of 2022 was due to the decrease since March 31, 2022 in the estimated fair value of Sutro’s holdings of Vaxcyte common stock. Vaxcyte common stock held by Sutro will be remeasured at fair value based on the closing price of Vaxcyte’s common stock on the last trading day of each reporting period, with any non-operating, unrealized gains and losses recorded in Sutro’s statements of operations.

Revenue

Revenue was $28.1 million for the quarter ended June 30, 2022, as compared to $28.0 million for the same period in 2021, related principally to recognition of the upfront payment from Tasly in the second quarter of 2022 and the Merck, BMS, and EMD Serono collaborations in both years. Future collaboration revenue from Astellas, Tasly, Merck, BMS, and EMD Serono, and from any additional collaboration partners, will fluctuate as a result of the amount and timing of revenue recognition of upfront, milestones, and other collaboration agreement payments.

Operating Expenses

Total operating expenses for the quarter ended June 30, 2022 were $47.5 million, as compared to $37.9 million for the same period in 2021. The second quarter of 2022 includes non-cash expenses for stock-based compensation of $6.7 million and depreciation and amortization of $1.4 million, as compared to $5.9 million and $1.1 million, respectively, in the comparable 2021 period. Total operating expenses for the quarter ended June 30, 2022 were comprised of research and development expenses of $32.3 million and general and administrative expenses of $15.1 million, which are expected to increase in 2022 as Sutro’s internal product candidates advance in clinical development and additional general and administrative expenses are incurred as a public company.

About Sutro Biopharma

Sutro Biopharma, Inc., headquartered in South San Francisco, is a clinical-stage oncology company pioneering site-specific and novel-format antibody drug conjugates (ADCs). Sutro has two wholly owned ADCs in the clinic—STRO-002, a folate receptor alpha (FolRα)-targeting ADC, in clinical studies for ovarian and endometrial cancers; and STRO-001, a CD74-targeting ADC, in clinical studies for B-cell malignancies. Additionally, Sutro is collaborating with Bristol Myers Squibb (BMS) on CC-99712, a BCMA-targeting ADC in the clinic for patients with multiple myeloma; with Merck KGaA, Darmstadt, Germany, known as EMD Serono in the U.S. and Canada (EMD Serono), on M1231, a MUC1-EGFR bispecific ADC in clinical studies for patients with solid tumors, particularly non-small cell lung cancer (NSCLC) and esophageal squamous cell carcinoma; with Merck, known as MSD outside of the United States and Canada, on MK-1484, a selective IL-2 agonist in clinical studies as a monotherapy and in combination with pembrolizumab for the treatment of solid tumors; and with Astellas Pharma (Astellas) on novel modality, immunostimulatory antibody-drug conjugates (iADCs). Sutro’s platform technology also enabled the spin out of Vaxcyte (Nasdaq: PCVX) and the creation of VAX-24, a 24-valent pneumococcal conjugate vaccine in clinical studies for the prevention of invasive pneumococcal disease. Sutro’s rational design and precise protein engineering has enabled six product candidates in the clinic. Follow Sutro on Twitter, @Sutrobio, and at www.sutrobio.com to learn more about our passion for changing the future of oncology.

Forward-Looking Statements

This press release contains forward-looking statements within the meaning of the “safe harbor” provisions of the Private Securities Litigation Reform Act of 1995, including, but not limited to, anticipated preclinical and clinical development activities, timing of announcements of clinical results and regulatory filings, potential benefits of STRO-002 and the Company’s other product candidates and platform, potential future milestone and royalty payments, and potential market opportunities for STRO-002 and the Company’s other product candidates. All statements other than statements of historical fact are statements that could be deemed forward-looking statements. Although the Company believes that the expectations reflected in such forward-looking statements are reasonable, the Company cannot guarantee future events, results, actions, levels of activity, performance or achievements, and the timing and results of biotechnology development and potential regulatory approval is inherently uncertain. Forward-looking statements are subject to risks and uncertainties that may cause the Company’s actual activities or results to differ significantly from those expressed in any forward-looking statement, including risks and uncertainties related to the Company’s ability to advance its product candidates, the receipt and timing of potential regulatory designations, approvals and commercialization of product candidates and the Company’s ability to successfully leverage Fast Track designation, the market size for the Company’s product candidates to be smaller than anticipated, the impact of the COVID-19 pandemic on the Company’s business, clinical trial sites, supply chain and manufacturing facilities, the Company’s ability to maintain and recognize the benefits of certain designations received by product candidates, the timing and results of preclinical and clinical trials, the Company’s ability to fund development activities and achieve development goals, the Company’s ability to protect intellectual property, the value of the Company’s holdings of Vaxcyte common stock, and the Company’s commercial collaborations with third parties and other risks and uncertainties described under the heading “Risk Factors” in documents the Company files from time to time with the Securities and Exchange Commission. These forward-looking statements speak only as of the date of this press release, and the Company undertakes no obligation to revise or update any forward-looking statements to reflect events or circumstances after the date hereof.

Investor Contact

Annie J. Chang

Sutro Biopharma

(650) 801-5728

ajchang@sutrobio.com

Media Contact
Amy Bonanno

Solebury Trout

(914) 450-0349

abonanno@soleburytrout.com

Sutro Biopharma, Inc.

Selected Statements of Operations Financial Data

(Unaudited)

(In thousands, except share and per share amounts)

Sutro Biopharma, Inc.

Selected Balance Sheets Financial Data

(Unaudited)

(In thousands)

(1) The condensed balance sheet as of June 30, 2022 was derived from the unaudited financial statements included in the Company's Quarterly Report on Form 10-Q for the quarter ended June 30, 2022, filed with the Securities and Exchange Commission on August 8, 2022.

(2) The condensed balance sheet as of December 31, 2021 was derived from the audited financial statements included in the Company's Annual Report on Form 10-K for the year ended December 31, 2021, filed with the Securities and Exchange Commission on February 28, 2022.