BHV‑1510 Trop2‑TopoIx ADC Shrinks Tumors in 6/6 Patients; FGFR3 ADC BHV‑1530 Enters Clinic

BHV‑1510 is a Trop2‑targeted antibody—drug conjugate armed with Biohaven’s proprietary TopoIx topoisomerase I payload; in the first Phase 1 cohorts (monotherapy and in combo with the anti‑PD‑1 antibody cemiplimab) all 6 evaluable combination‑treated patients, 4 of whom had NSCLC and RECIST responses in 3 out of 6 (50% ORR) —most having failed prior PD‑1/PD‑L1 therapy and some with brain metastases—achieved confirmed partial responses, while monotherapy cohorts have also shown tumor reductions. Stomatitis has been the main toxicity; to date there have been no cases of interstitial‑lung disease, severe diarrhea, or grade ≥3 hematologic events, and systemic free payload levels remain low. By comparison, the approved Trop2 ADC sacituzumab govitecan causes grade 3‑4 neutropenia in ~37% of patients and datopotamab deruxtecan has reported grade ≥3 ILD in 3‑4% of cases. Biohaven also dosed the first patient with BHV‑1530, the first FGFR3‑directed TopoIx ADC—an early move into urothelial and other FGFR3‑driven tumors where the small‑molecule inhibitor erdafitinib achieves ~40% response but is limited by ocular toxicity.