Rapid CAR-T manufacturing with low-intensity priming enhances CAR-T cell fitness and limits inflammatory programming in a phase 1 study.

Conventional chimeric antigen receptor (CAR)-T manufacturing requires prolonged ex vivo activation and expansion, which may compromise T cell fitness and promote inflammatory differentiation. Here, we developed PrimeCAR, a 2-day manufacturing strategy combining low-intensity anti-CD3 priming with IL-7 and IL-21. Compared with conventionally manufactured CAR-T cells, PrimeCAR products exhibited a distinct transcriptional state characterized by preserved stemness-associated programs and a PrimeCAR-enriched primed naive T cell (Tn)-like state. Following antigen stimulation, PrimeCAR cells preferentially engaged proliferative programs while limiting exhaustion-associated regulators and inflammatory mediators. Functionally, PrimeCAR cells demonstrated enhanced expansion, persistence, and durable antitumor activity in xenograft models. In investigator-initiated phase I studies of relapsed or refractory B cell acute lymphoblastic leukemia and B cell non-Hodgkin lymphoma, PrimeCAR showed encouraging clinical activity with a favorable safety profile. Together, these findings demonstrate that rapid manufacturing with controlled early T cell priming selectively restrains inflammatory programming while preserving CAR-T cell fitness, providing a practical strategy for improving CAR-T manufacturing and therapeutic performance.