On March 23, 2026 Sutro Biopharma, Inc. (Sutro or the Company) (NASDAQ: STRO), a clinical-stage oncology company pioneering site-specific and novel-format antibody drug conjugates (ADCs), reported its financial results for the full year 2025 and recent business highlights.
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"2026 is poised to be a pivotal year, propelled by disciplined clinical execution and initial data that we believe will showcase the vast potential of our proprietary ADC platform," said Jane Chung, Sutro’s Chief Executive Officer. "We recently completed dosing the third cohort in the Phase 1 trial of STRO-004, our potential best-in-class Tissue Factor ADC, and look forward to reporting initial data mid-year. In parallel, we are advancing STRO-006, our ITGB6 ADC, and accelerating STRO-227, our wholly owned dual-payload program targeting PTK7, toward IND submission this year. In addition, patient dosing has commenced under our collaboration with Astellas Pharma for our first partnered dual-payload iADC — marking the first dual-payload program from Sutro’s platform to enter the clinic. Supported by our recent financing, continued financial stewardship, and sharpened strategic focus, we believe we are well positioned to execute across all our programs and deliver differentiated ADCs with best-in-class potential that could redefine standards of care in oncology."
Wholly Owned Pipeline
STRO-004: The Company has completed dosing across three cohorts in the first-in-human Phase 1 trial evaluating STRO-004, a DAR8 Topo1 ADC targeting Tissue Factor (TF), with potential as best-in-class TF ADC. Initial clinical data are expected in mid-2026, including safety and tolerability. Sutro also expects to share pharmacokinetic exposure and potentially early signs of activity. In non-human primate studies, STRO-004 demonstrated a favorable preclinical safety profile, with a highest non-severely toxic dose (HNSTD) of 50 mg/kg — supporting a clinical starting dose of 1mg/kg.
STRO-006: A highly selective, DAR 8 Topo1 ADC targeting integrin β6 (ITGB6), STRO-006 is expected to enter clinical development in 2026 for the treatment of multiple solid tumors.
STRO-227: Sutro’s PTK7-targeting dual-payload ADC program, consisting of MMAE (DAR2) and Topo1 (DAR8), remains on track, with an IND submission targeted for 2026.
Next-Generation ADC Collaborations
Astellas: Two research and development programs are progressing under Sutro’s collaboration with Astellas focused on dual-payload immunostimulatory ADCs (iADCs).
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The first program, targeting TROP2, has entered the clinic and is actively dosing patients, triggering a $10 million milestone payment with receipt expected in the second quarter of 2026.
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The second program entered an IND-enabling toxicology study in the fourth quarter of 2025, triggering a $7.5 million milestone payment to Sutro.
Upcoming and Recent Industry/Medical Conferences
American Association for Cancer Research (AACR) (Free AACR Whitepaper), April 17-22, 2026, San Diego California
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Sutro’s strategic partner, Astellas Pharma, will present preclinical results from its TROP2-targeted iADC program in an oral presentation on Sunday, April 19, 2026 at 4:35-4:50 PM PT. The presentation, titled "ASP2998, a TROP2-targeted immunostimulatory antibody-drug conjugate (iADC) with dual payloads, demonstrates potent efficacy and a favorable safety profile in nonclinical models," highlights progress in the development of next-generation iADCs leveraging Sutro’s cell-free protein synthesis platform.
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Additionally, Sutro will present an oral presentation and multiple posters highlighting advances across its ADC pipeline and discovery platforms at AACR (Free AACR Whitepaper). The presentation details are as follows:
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Presentation: "STRO-004, an exatecan-based next-generation tissue factor (TF)-targeted ADC, demonstrates superior efficacy across TF-expressing solid tumors in a comprehensive single-mouse PDX trial"
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Presentation Date and Time: Sunday, April 19, 2026; 4:35-4:50 PM PT
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Poster: "Phase 1 open-label study to evaluate safety, pharmacokinetics, and preliminary anti-tumor activity of STRO-004 in adults with refractory/recurrent metastatic solid tumors"
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Session Date and Time: Monday, April 20, 2026; 9:00 AM-12:00 PM PT
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Poster: "STRO-006: An Integrin beta-6–targeting ADC demonstrates favorable safety profile and potent antitumor activity in preclinical solid tumors"
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Session Date and Time: Monday, April 20, 2026; 9:00 AM-12:00 PM PT
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Poster: "Preclinical characterization of STRO-227: A PTK7-targeting dual-payload ADC with topoisomerase 1 and tubulin inhibitors"
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Session Date and Time: Monday, April 20, 2026; 9:00 AM-12:00 PM PT
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Poster: "The HER2-targeting dual-payload antibody-drug conjugate combining a topoisomerase I inhibitor and a microtubule inhibitor demonstrates superior efficacy and overcomes resistance to single-payload ADCs in xenograft models"
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Session Date and Time: Monday, April 20, 2026; 9:00 AM-12:00 PM PT
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Poster: "Sutro’s Site-Specific Dual-Payload ADCs Combining TOPO1i and DNA Damage Response Inhibitors to Enhance Efficacy, Overcome Resistance, and Improve Safety"
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Session Date and Time: Tuesday, April 21, 2026; 9:00 AM-12:00 PM PT
16th World ADC London Summit, February 23-26, 2026, London, UK
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Sutro participated in a plenary and two panel discussions at the conference, covering topics including dual-payload innovation, key drivers of ADC differentiation, and ADC collaborations. For more details, read the full press release here.
Corporate Updates
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Sutro strengthened its cash position with an underwritten offering of 7,868,383 shares of its common stock at a price of $13.98 per share, resulting in gross proceeds of $110.0 million, before deducting underwriting discounts and commissions and other offering expenses payable by Sutro. The Company’s cash runway is now expected into at least the second quarter of 2028, excluding additional anticipated milestones from Sutro’s existing collaboration.
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Sutro management, joined by KOL Anthony Tolcher, M.D., FRCPC, FACP, hosted a virtual R&D Day on Wednesday, November 12, highlighting the Company’s platform innovations and next-generation ADC pipeline. Key updates included the initiation of the Phase 1 study with STRO-004 and the selection of PTK7 as the target for its initial dual-payload candidate, STRO-227.
Full Year 2025 Financial Highlights
Cash, Cash Equivalents and Marketable Securities
As of December 31, 2025, Sutro had cash, cash equivalents and marketable securities of $141.4 million, as compared to $167.6 million as of September 30, 2025. With gross proceeds from the recent financing totaling $110.0 million, the Company’s cash runway is expected into at least the second quarter of 2028, excluding anticipated milestones from Sutro’s existing collaborations.
Revenue
Revenue was $102.5 million for the year ended December 31, 2025, as compared to $62.0 million for the year ended December 31, 2024, with the 2025 amount related principally to the Astellas and Ipsen collaborations. Future collaboration and license revenue under existing agreements, and from any additional collaboration and license partners, will fluctuate as a result of the amount and timing of revenue recognition of upfront, milestones, and other agreement payments.
Research & Development (R&D) and General & Administrative (G&A) Expenses
Total R&D and G&A expenses for the year ended December 31, 2025 were $207.4 million, as compared to $300.5 million for the year ended December 31, 2024. The 2025 year includes non-cash expenses for stock-based compensation of $14.0 million and depreciation and amortization of $7.3 million, as compared to $24.7 million and $7.2 million, respectively, in the comparable 2024 period.
Restructuring Costs
The total cash payments and costs related to the further operational restructuring announced on September 29, 2025 are estimated to be approximately $4.1 million to $4.3 million, with a majority of these amounts paid in the fourth quarter of 2025. These estimates are subject to a number of assumptions and actual results may differ. The Company may also incur additional costs not currently contemplated due to events that may occur as a result of, or that are associated with, the corporate restructuring.
(Press release, Sutro Biopharma, MAR 23, 2026, View Source [SID1234663834])