BDC-4182's Phase 1 readout in gastric/GEJ cancer will determine whether immune-activating antibody conjugates can generate durable clinical responses where checkpoints fall short

Bolt Biotherapeutics is a clinical-stage company developing a targeted cancer drug for gastric and gastroesophageal junction cancer, a treatment not yet approved.

BDC-4182 is an immune-stimulating antibody conjugate targeting HER2-expressing gastric and gastroesophageal junction tumors, a setting with high unmet need and limited durable responses. The thesis turns on whether Q3 2026 Phase 1 data show objective tumor responses, not merely immune activation signals, validating the ISAC mechanism as clinically meaningful. The primary risks are competition from established HER2-directed agents like trastuzumab deruxtecan and the slim runway that leaves no margin for trial delays or financing gaps.