A phase I clinical trial of adoptive transfer of folate receptor-alpha redirected autologous T cells for recurrent ovarian cancer

Purpose: In spite of increased rates of complete response to initial chemotherapy, most patients with advanced ovarian cancer relapse and succumb to progressive disease. Rationale: Genetically reprogrammed, patient-derived chimeric antigen receptor (CAR)-T lymphocytes with the ability to recognize predefined surface antigens with high specificity in a non-MHC restricted manner have shown increasing anti-tumor efficacy in preclinical and clinical studies. Folate receptor-alpha (FR alpha) is an ovarian cancer-specific tumor target; however, it is expressed at low levels in certain organs with risk for toxicity. Design: Here we propose a phase I study testing the feasibility, safety and preliminary activity of FR alpha-redirected CAR-T cells bearing the CD137 (4-1BB) costimulatory domain, administered after lymphodepletion for the treatment of recurrent ovarian cancer. A novel trial design is proposed that maximizes safety features. Innovation: This design involves an initial accelerated dose escalation phase of FR-alpha CAR-T cells followed by a standard 3 + 3 escalation phase. A split-dose approach is proposed to mitigate acute adverse events. Furthermore, infusion of bulk untransduced autologous peripheral blood lymphocytes (PBL) is proposed two days after CAR-T cell infusion at the lower dose levels of CAR-T cells, to suppress excessive expansion of CAR-T cells in vivo and mitigate toxicity.