GPNMB as a viable CAR Target for MITF pathognomonic fusion-driven cancers: A first-in-person GCAR1 Trial [ASPS-02_VisiumHD]

We identify the MITF-driven gene GPNMB as being highly, homogeneously and stably expressed from primary and relapsed translocation-positive alveolar soft part sarcoma (ASPS) and renal cell carcinoma (tRCC). We developed a 2nd generation GPNMB-targeting CAR T therapy (GCAR1) that shows activity against cells, organoids and PDX models.

First-in-person GCAR1 treatment of a patient with metastatic ASPS was well tolerated and generated stable disease for 6 months, with the majority of non-target lung lesions resolving post-treatment. A diverse population of GCAR1 cells expanded in blood, peaking at 14 days post-treatment. Spatial transcriptomics revealed immunosuppression, including PDL1 expression, in close proximity to T cells infiltrating a treatment-resistant lung lesion, and PDL1 blockade showed synergy with GCAR1 in a PDX model.