EGFR×HER3 bispecific ADC logs 40% responses in PD‑1‑refractory metastatic ESCC

BL‑B01D1 pairs an EGFR‑HER3 bispecific antibody with a cleavable topoisomerase I payload; in the phase 1b NCT05262491 study, 82 heavily pre‑treated ESCC patients received 2.0 or 2.5 mg/kg every 3 weeks. Overall confirmed ORR was 29.3%, but rose to 39.6% (DCR 79%) at the RP2D 2.5 mg/kg (n = 53); grade ≥3 TRAEs at this dose were 63%—chiefly anemia (28%) and cytopenias (~18%), with two ≥G3 interstitial lung disease events. Conventional salvage taxanes or irinotecan yield 13‑30% ORR with comparable toxicity and limited durability, underscoring the ADC’s relative potency.