PTPN2 Deletion Enhances CAR-T Effector Function and CNS Trafficking in a Non-Human Primate Model

B-cell targeting CAR-T cells (CAR-T) therapies achieve high remission rates, yet durable responses occur in fewer than 40% of patients. Deletion of negative T-cell regulators such as PTPN2, a key inhibitor of TCR and cytokine signaling, represents a promising strategy to enhance CAR-T efficacy. While transfer of PTPN2-knockout (KO) T cells has demonstrated antitumor benefits in murine models, their impact on human-derived CAR-Ts and, importantly, the associated in vivo efficacy and toxicity remain unclear. Here, we demonstrate that PTPN2-KO human CD19 CAR-Ts exhibit enhanced cytokine production, proliferation, cytotoxicity, TCR and CAR functional avidity and signaling, which together lead to superior in vitro elimination of leukemic cells with low CD19 expression. In an in vivo dose-escalation study in a non-human primate (NHP) model of CD20/B-cell-targeting CAR-T therapy, we demonstrated that PTPN2-KO CAR-Ts exhibited superior in vivo expansion and B-cell depletion in a dose-dependent manner than PTPN2-WT CAR-Ts. PTPN2-KO CAR-T expansion was associated with increased toxicities, particularly neurotoxicity/ICANS, compared to WT CAR-Ts, driven by enhanced CNS-infiltration. Transcriptional profiling revealed a dominant effector and proliferative signature, with cytotoxic CNS-infiltrating CD8+ PTPN2-KO CAR-Ts implicated in ICANS pathogenesis. This study details the comprehensive evaluation of PTPN2-KO CAR-Ts in an immunocompetent primate model, demonstrating their enhanced on-target functionality, while highlighting increased toxicity risks, underscoring the value of rigorous preclinical assessment of potent genetic modifications in CAR-T therapy.