Molecular Partners shares rise 11.46% after-hours after presenting preclinical data on logic-gated CD3 Switch-DARPin TCE showing selective tumor targeting and safety.

Molecular Partners surged 11.46% in after-hours trading following the presentation of preclinical proof-of-concept data on its logic-gated CD3 Switch-DARPin T cell engager at SITC 2025. The data demonstrated selective T cell cytotoxicity against tumor cells co-expressing MSLN and EpCAM, significant tumor regression in vivo without systemic cytokine release, and enhanced T cell activation via CD2 co-stimulation. These findings highlight the platform’s potential to address limitations in current TCEs for solid tumors, including improved safety and efficacy. The AND-gate mechanism, which activates T cells only when both antigens are present, positions the technology as a novel approach to targeted immunotherapy. The positive preclinical results reinforce the company’s oncology focus and DARPin therapeutic platform, likely driving investor optimism about future clinical development and commercial potential.