Sutro Biopharma (STRO) investor relations material

Strategic program execution

• Achieved accelerated clinical development, advancing three programs into the clinic within two years, ahead of the original three-year goal.

• STRO-004, a tissue factor targeting ADC, is in phase I with promising early activity and favorable safety across multiple tumor types beyond cervical cancer.

• STRO-006, targeting integrin beta 6, has IND clearance and is initiating clinical trials, leveraging similar design and safety advantages as STRO-004.

• Dual payload ADC program (STRO-227) is on track for IND submission later this year, aiming to overcome resistance seen with single payload ADCs.

• Platform enables rapid optimization and differentiation through higher DARs and tailored payload ratios.

Clinical and preclinical data highlights

• STRO-004 demonstrates robust drug exposure, favorable PK, and low free payload levels, supporting a strong safety profile.

• Phase I STRIVE trial enrolled 49 patients in three months, showing early responses in PDAC, head and neck, and lung cancers.

• Dose escalation reached 4–5 mg/kg, double the dose of competitors, with low discontinuation rates and minimal dose-limiting toxicities.

• Safety profile is differentiated, with low rates of neutropenia and platelet count decrease compared to conventional ADCs.

• PK data show nearly seven-day half-life and preservation of DAR-8 configuration at high levels.

Pipeline innovation and differentiation

• Dual payload ADCs offer potential to overcome resistance in tumor models, outperforming single payload and co-administered agents.

• Technology allows for precise stoichiometry and higher dosing in non-human primates, supporting safety and efficacy.

• Preclinical models show robust activity in lung, triple-negative breast, and ovarian cancers with dual payload constructs.

• Collaborations, such as with Astellas, are advancing dual payload ADCs into the clinic, including immunostimulatory combinations.

• Platform enables optimization of antibody, linker, and payload for improved stability and reduced toxicity.