Rejuvenated Hematopoietic Stem and Progenitor Cell-Engineered CAR-Armored Natural Killer T Cells for Malignant...

Malignant pleural mesothelioma (MPM) is a rare and highly aggressive malignancy arising from the pleural lining, characterized by a dismal prognosis and limited therapeutic options. Mesothelin (MSLN)-directed chimeric antigen receptor (CAR)-armored T (CAR-T) cell therapies have shown encouraging preliminary outcomes; however, autologous manufacturing approaches remain constrained by logistical complexity and prolonged production timelines, which are suboptimal for patients with rapidly advancing disease. Here, we describe the development of human allogeneic interleukin-15-augmented, MSLN-specific, CAR-armored invariant natural killer T (^Allo15MCAR-NKT) cells. These cells are generated through genetic modification of hematopoietic stem and progenitor cells, followed by a clinically guided CAR-NKT cell differentiation, maturation, and expansion process. This approach supports scalable production with high cellular yield, purity, and translational feasibility. Functionally, ^Allo15MCAR-NKT cells exhibit robust antitumor efficacy in vitro and demonstrate robust therapeutic activity across multiple in vivo MPM xenograft models, including subcutaneous and lung metastasis models. In addition, they actively modulate the tumor microenvironment by targeting CD1d⁺ tumor-associated macrophages. Phenotypic analysis reveals a rejuvenated cellular profile, marked by low expression of exhaustion-associated and inhibitory receptors, including PD-1, TIM-3, LAG-3, CTLA-4, and TIGIT, consistent with sustained functional capacity. Importantly, these cells display a favorable safety profile, with minimal evidence of graft-versus-host disease, cytokine release syndrome, brain infiltration or neurotoxicity, and no detectable off-tumor effects. Collectively, these findings support the development of a clinically translatable, off-the-shelf CAR-NKT cell therapy for the treatment of MPM.