Pipeline and Milestones - Sutro is developing a differentiated pipeline of single- and dual-payload ADCs, focusing on complex targets and overcoming resistance [12, 13] - Initial Phase 1 data for STRO-004, a Tissue Factor (TF)-targeting ADC, is expected in mid-2026 [12, 59] - An IND submission for STRO-006, an ITGB6-targeting ADC, is expected in 2026 [12, 59] - An IND submission for STRO-227, a PTK7-targeting dual-payload ADC, is expected in 2026-2027 [13, 50, 59] - The first immunostimulatory ADC (iADC) program is expected to enter the clinic in early 2026 [56, 59] STRO-004 (TF-Targeting ADC) - STRO-004 demonstrated promising anti-tumor activity in multiple TF-expressing cancer models, with a disease control rate (DCR) of 93% (28/30) and an overall response rate (ORR) of 73% (22/30) in PDX models [25] - STRO-004 is well-tolerated at 50 mg/kg in non-human primates (NHPs) [12] STRO-006 (ITGB6-Targeting ADC) - STRO-006 is designed for superior selectivity, safety, and stability, targeting ITGB6 [32] - In HNSCC PDX models, STRO-006 at 5 mg/kg showed superior anti-tumor activity compared to aITGB6 ADC (DAR4 MMAE) at 5 mg/kg, with an ORR of 71% (12/17) vs 47% (8/17) [37] - In HNSCC PDX models, STRO-006 showed ADC response (below baseline) at end of study 64% (7/11) vs aITGB6 DAR4 MMAE 27% (3/11) [38] Dual-Payload ADCs - Dual-payload ADCs have the potential to overcome resistance resulting from conventional ADCs and reduce toxicity compared to ADC combination approaches [44]