A new CAR-T design aimed at avoiding continuous activation showed early signals against multiple solid tumor types. Researchers at the University of Pennsylvania presented first-in-human Phase I data for SynKIR-110, a “KIR-CAR” construct built from NK receptor elements with a multi-chain architecture that turns on only after target engagement. In the dose-escalation study, nine patients with advanced mesothelin-expressing cancers—such as ovarian cancer, mesothelioma, and cholangiocarcinoma—received the therapy after an average of four prior treatment lines. The trial’s safety profile was described as favorable, with disease stabilization in four patients and one ongoing partial response in the highest dose cohort. The design rationale centers on reducing the risk of T-cell exhaustion by separating tumor recognition from activation, potentially improving durability in solid tumor microenvironments where conventional CAR-T often struggles. These early results will be followed by dose expansion and combination studies as the field tests whether “on-off” biology translates into durable responses.