Purple Biotech shares surge 21.09% premarket after positive CAPTN-3 preclinical data shows anti-tumor activity in PD-1 resistant models and platform versatility.

Purple Biotech surged 21.09% in premarket trading following the release of positive preclinical data for its CAPTN-3 tri-specific antibody platform at the ESMO IO 2025 congress. The platform demonstrated robust anti-tumor activity in PD-1–resistant models, including non-small cell lung cancer and head and neck squamous cell carcinoma, with candidates IM1240 and IM1305 showing sustained tumor regression in humanized mouse models. Transcriptomic analysis of 11,000 TCGA samples validated the NKG2A arm’s role in enhancing immune activation, supporting the platform’s potential for solid tumors. The results, presented in collaboration with Mount Sinai’s Dr. Amir Horowitz, highlight CAPTN-3’s ability to address immune evasion and resistance, with the company targeting IND-enabling milestones in 2026. The data underscores the platform’s versatility and therapeutic promise, driving investor optimism.