GPC3-specific dnTGFβRII-armoured CAR T cells for hepatocellular carcinoma.

Abstract

Glypican-3 (GPC3) is highly expressed in hepatocellular carcinoma (HCC), making it an attractive target for chimeric antigen receptor (CAR) T cell therapy; however, this approach has previously shown limited clinical efficacy, potentially owing to high levels of transforming growth factor-β (TGFβ) in the tumour microenvironment^1-4. We therefore engineered CAR T cells with a dominant-negative TGFβ receptor II, which showed enhanced antitumour activity in preclinical studies⁵. Here we report findings from a first-in-human trial evaluating the safety and efficacy of C-CAR031 in patients with advanced, treatment-refractory HCC ( NCT05155189 ). Thirty-six patients received CAR T infusions at four dose levels (from 0.75 × 10⁶ to 4.0 × 10⁶ cells per kg). Cytokine release syndrome was reported in 34 patients, of which two cases were grade 3. Nine patients had non-haematological adverse events of grade 3 or higher. Tumour regression was observed in 32 patients, with a median best tumour reduction from baseline of 41.6% (range: 3.4-94.4%) in target lesions. The objective response rate was 44.4%, and the median duration of response was 4.4 months (95% confidence interval: 2.9-7.4). Median progression-free survival and overall survival were 4.2 months (95% confidence interval: 2.9-4.8) and 14.2 months (95% confidence interval: 10.1 to not evaluable), respectively. High-throughput analyses of tumour samples and functional validation suggested that GPC3 antigen loss and increased TGFβ levels may contribute to C-CAR031 resistance. Collectively, these results indicate that C-CAR031 has a manageable safety profile and encouraging antitumour activity in heavily pretreated patients with advanced HCC.