A phase I clinical trial of malignant pleural mesothelioma treated with locally delivered autologous anti-FAP-targeted CAR T-cells

Abstract

Background Malignant pleural mesothelioma (MPM) is a cancer with a worldwide increasing incidence due to the use of asbestos. MPM is incurable despite the use of multimodality treatment. Tumor spread confined to the thoracic cavity is a hallmark of MPM, providing a rational for local treatment. We developed a chimeric antigen receptor (CAR) targeting FAP (fibroblast activating protein), a cell-surface antigen that we have shown to be highly expressed in epithelial cancers. Methods Using a Δ-CD28-costimulated CAR, we initiated a phase I clinical trial (NCT01722149) to determine the safety and persistence of intra-pleural administered anti-FAP-CAR T cells in the periphery. A single dose of 1x 106 re-directed T cells was administered through a pleural catheter. Patients were monitored on an intensive care unit for 48h. Clinical evaluations of on-target and off-tumor toxicity were assessed for 3 months. Laboratory analyses included cytokines, CRP and the detection of CAR-T cells in the pleural effusion and blood over time. Radiological evaluation with PET-CT scans was performed as standard of care. Results Three patients with metastatic MPM were treated (all patients received at least two cycles of chemotherapy previous to CAR T-cell administration). No CAR T-cell-related toxicities were observed. Intense monitoring for cytokine release syndrome showed significant changes on a subset of cytokines. CAR T-cells were detected in the peripheral blood after treatment. Activity of the patient’s redirected T cells was confirmed in vitro. Furthermore, one patient received an anti-PD1 checkpoint blockade antibody 8 months after CAR T-cell instillation with no toxicity. With a median follow-up of 18 months, 2 out of 3 patients are alive. Conclusions In this phase I clinical trial, intra-pleural administration of anti-FAP CAR T-cells was well tolerated without any evidence of treatment related toxicity. Persistence of CAR T-cells was documented in the periphery.