Sutro Biopharma (STRO) Corporate presentation summary

Platform and strategy

• Cell-free ADC platform combines optimized antibodies, site-selective payload placement, a stable β-glu linker and high-DAR or dual-payload designs to target efficacy, selectivity and tolerability.

• Single-payload ADCs address complex targets; dual-payload designs aim to overcome resistance, delay progression and deliver combined payloads within tumor cells.

• Platform data emphasize stable ADC exposure and low free-payload levels; STRO-004 maintained 98% DAR8 and a nearly 7-day half-life across studied doses.

STRO-004 clinical program

• Phase 1 dose escalation covered 1–5 mg/kg in 49 heavily pretreated patients across 8 tumor types; confirmed and ongoing unconfirmed partial responses occurred in PDAC, HNSCC and NSCLC.

• Mostly grade 1–2 adverse events; 6% discontinued due to adverse events, with no discontinuations due to dose-limiting toxicities.

• Exposure was dose-proportional, with low free circulating payload; all-grade treatment-related events above 15% included nausea (33%), fatigue (29%) and anemia (18%).

• Next study update and initiation of expansion cohorts in select indications planned for 1H 2027.

STRO-006 and STRO-227

• STRO-006 Phase 1 began in 3Q 2026, with initial clinical data expected in 2H 2027; the DAR8 exatecan ADC targets ITGβ6.

• In solid-tumor PDX models, STRO-006 produced responses in 43/58 models (74%) at 5 mg/kg across HNSCC, lung adenocarcinoma and squamous NSCLC.

• STRO-227 is a PTK7-targeting dual-payload ADC combining exatecan and MMAE; Phase 1 initiation is expected in early 2027.

• Preclinical models showed STRO-227 activity in selected NSCLC, TNBC and ovarian PDX models, including models that had progressed on single-payload ADCs.