STRO-004 - (STRIVE-01)

Aug. 12, 2026: Sutro Biopharma (NASDAQ: STRO) reported Q2 2026 results and an R&D update centered on STRO-004, a tissue factor-targeting DAR8 exatecan ADC in the Phase 1 STRIVE-01 study for advanced solid tumors. In 49 heavily pretreated patients across dose levels 1-5 mg/kg, the company reported confirmed and ongoing unconfirmed partial responses in pancreatic, head and neck, and non-small cell lung cancer at 3-4 mg/kg. The study is optimizing between 4 and 5 mg/kg; maximum tolerated dose has not been defined. Discontinuation due to adverse events was 6%. Common all-grade treatment-related AEs were nausea (33%), fatigue (29%), and anemia (18%); grade 3+ anemia was 14%. DLTs occurred only at 5 mg/kg. PK showed dose-proportional exposure, nearly 7-day half-life, preserved 98% DAR8 configuration, and no evidence of target-mediated drug disposition. Next STRIVE-01 update and expansion cohort initiation are planned for 1H 2027.

STRO-006, an ITGB6-targeting ADC for solid tumors, is expected to enter Phase 1 in Q3 2026. STRO-227, a PTK7-targeting dual-payload ADC, remains on track for IND submission in 2026. Under the Astellas collaboration, the TROP2 dual-payload iADC is dosing patients; Sutro received a $10 million milestone in April 2026, and a second partnered program is expected to enter the clinic by end-2026. Cash, cash equivalents, and marketable securities were $164.3 million as of June 30, 2026, with runway projected into at least Q2 2028.