Sutro Biopharma (STRO) investor relations material

Strategic transformation and technology differentiation

• Underwent a major strategic pivot in March, focusing on advancing a differentiated ADC pipeline using proprietary cell-free technology to optimize every ADC component for improved efficacy and safety.

• Cell-free system enables higher ADC drug exposure (2–3x conventional methods), iterative design, and site-specific conjugation beyond cysteine or lysine, enhancing PK, safety, and efficacy.

• Fc silent, non-glycosylated antibodies reduce risks like ocular toxicity and ILD, especially relevant for lung cancer indications.

• Manufacturing largely externalized to CDMO partners, with only specialized cell-free antibody work kept in-house, reducing costs and improving scalability.

• Cash runway extends into Q2 2028, supporting all current pipeline programs through initial proof-of-concept data.

Pipeline progress and clinical milestones

• Three programs advancing toward the clinic, with STRO-004 already in phase I and two more (STRO-006, STRO-227) on track for IND submissions this year.

• STRO-004 (tissue factor ADC) features a DAR 8 exatecan payload and optimized linker, aiming for a best-in-class safety and efficacy profile; initial top-line phase I data expected mid-year.

• STRO-006 (integrin beta 6 ADC) targets lung and other cancers, with high tolerated doses and a focus on both safety and anti-tumor activity; IND planned for this year.

• Dual payload ADC program timeline accelerated to IND submission later this year, aiming to overcome resistance seen with single payload ADCs.

• Collaboration with Astellas on an IO dual payload ADC has dosed its first patient, with data anticipated in the coming years.

Competitive positioning and future outlook

• STRO-004 differentiated from Tivdak by higher safety ceiling (HNSTD 50 mg/kg vs. 2 mg/kg) and reduced toxicity, with plans to pursue multiple tumor types beyond cervical cancer.

• STRO-006 positioned as a fast follower to Pfizer in integrin beta 6, leveraging platform strengths and targeting additional indications like head and neck and esophageal cancers.

• Dual payload ADCs designed to address resistance mechanisms and deliver high safety at potent doses, with preclinical data supporting durable responses.

• PTK7 dual payload program aims for a differentiated profile in an open space, with IND submission accelerated to this year.

• Key milestones for the next 6–12 months include phase I data for STRO-004, INDs for STRO-006 and STRO-227, and further validation of the dual payload platform.