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PTPN2-KO CAR-T Cells Demonstrate Enhanced Effector Function, CNS Infiltration, and Toxicity in a Non-Human Primate
Abstract:
B-cell targeting CAR-T cell 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 the efficacy of CAR-T cells. While transfer of PTPN2 knockout (KO) T cells has demonstrated antitumor benefits in murine models, its impact on human-derived CAR-T cells and, importantly, the associated in vivo efficacy and toxicity remain unclear. Here, we demonstrate that PTPN2-KO human CD19 CAR-T cells exhibit enhanced cytokine production, cytotoxicity, TCR and CAR affinity and signaling, leading to superior in vitro elimination of leukemic cells with low CD19 expression. To assess in vivo efficacy and toxicity, we performed a dose-escalation study using a non-human primate (NHP) model of B-cell-targeting CD20 CAR-T cell therapy. We demonstrated that PTPN2-KO CD20 CAR-T cells exhibited superior in vivo expansion and B-cell depletion compared to WT CAR-T cells, in a dose-dependent manner. At the highest dose level, CAR-T expansion was associated with increased toxicities, particularly ICANS, compared to PTPN2 WT CD20 CAR-T cells driven by enhanced CNS-infiltration. Transcriptional profiling revealed a dominant effector and proliferative signature, with cytotoxic CNS-infiltrating CD8+ PTPN2-KO CAR-T cells implicated in ICANS pathogenesis. This study details the comprehensive evaluation of PTPN2-KO CAR-T cells in an immunocompetent model, demonstrating their enhanced on-target functionality, while highlighting increased toxicity risks, underscoring the need for rigorous preclinical assessment of potent genetic modifications in CAR-T therapy.
Key Points:
PTPN2-KO CAR-T cells exhibit enhanced effector functionIn a dose escalation study in rhesus macaques, PTPN2-KO mediated enhanced proliferation and CNS infiltration was associated with increased ICANS.
Insights
Deleting PTPN2 in chimeric antigen receptor T (CAR-T) cells enhances their ability to fight cancer. However, this modification also increases the risk of severe toxicities, particularly neurotoxicity, in preclinical models.
Area of Science:
- Immunology
- Cell Therapy
- Cancer Research
Background:
- Chimeric antigen receptor T (CAR-T) cell therapies show promise for B-cell malignancies but often lack durable responses.
- Enhancing CAR-T cell efficacy by deleting negative regulators like PTPN2 is a potential strategy.
- The impact of PTPN2 knockout (KO) on human CAR-T cells and associated in vivo toxicity is not well understood.
Purpose of the Study:
- To evaluate the in vitro and in vivo efficacy and toxicity of PTPN2-KO human CD19 CAR-T cells.
- To assess the impact of PTPN2 deletion on CAR-T cell function, expansion, and potential adverse effects in an immunocompetent model.
Main Methods:
- Generated PTPN2-KO human CD19 CAR-T cells and assessed their in vitro effector functions.
- Conducted a dose-escalation study using PTPN2-KO and wild-type (WT) CD20 CAR-T cells in a non-human primate (NHP) model.
- Analyzed CAR-T cell expansion, B-cell depletion, CNS infiltration, and toxicities, including immune effector cell-associated neurotoxicity syndrome (ICANS).
Main Results:
- PTPN2-KO CAR-T cells demonstrated enhanced cytokine production, cytotoxicity, and signaling in vitro, leading to superior leukemic cell killing.
- In vivo, PTPN2-KO CD20 CAR-T cells showed dose-dependent superior expansion and B-cell depletion in NHPs.
- Higher doses of PTPN2-KO CAR-T cells were associated with increased toxicities, including ICANS, driven by enhanced CNS infiltration of CD8+ T cells.
Conclusions:
- PTPN2 deletion enhances the on-target functionality of human CAR-T cells.
- While PTPN2-KO CAR-T cells exhibit improved efficacy, they also carry increased risks of severe toxicity, particularly ICANS.
- Rigorous preclinical evaluation is crucial for potent genetic modifications in CAR-T therapy to balance efficacy and safety.
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