A phase I/II clinical trial of E6 T-cell receptor gene therapy for human papillomavirus (HPV)-associated epithelial cancers

3009 Background: Engineered T-cell therapy has shown promise in B-cell malignancies and melanoma, but clinical investigation in epithelial cancers has been limited. Methods: We conducted a phase I/II clinical trial of T cells genetically engineered to express a T-cell receptor that targets an HLA-A*02:01-restricted epitope of E6 (E6 TCR T Cells) for patients with metastatic HPV-16+ carcinoma. The cell dose was escalated in cohorts of single patients (1 x 109, 1 x 1010, and 1-2 x 1011cells). Patients received a nonmyeloablative conditioning regimen of cyclophosphamide and fludarabine, a single infusion of E6 TCR T Cells, and systemic high-dose aldesleukin. Results: Twelve patients were treated, 9 at the highest cell dose, plus one retreatment. The cancer types were 6 cervical, 4 anal, 1 oropharyngeal, and 1 vaginal. No dose-limiting toxicity, autoimmune adverse events, or cytokine storm were observed. Two patients with anal cancer treated at the highest cell dose experienced partial tumor responses lasting 6 and 3 months after treatment. The patient with a 6-month response had complete regression of one tumor and partial regression of two tumors that were resected upon progression; she has no evidence of disease 22 months after treatment. T-cell receptor gene transfer efficiency was 45 and 51% in the responding patients, and 47-76% (median 61%) in the non-responding patients. Responding patients showed robust levels of E6 TCR T cell memory (30 and 46% of circulating T cells 1-month after treatment). Non-responding patients showed wide-ranging levels of E6 TCR T cell memory (range 4-53%, median 29%). Expression of programmed cell death protein 1 (PD-1) by circulating E6 TCR T Cells 1-month after treatment was low in all patients ( < 5%). The patient with a 6-month response had 7% E6 TCR T Cells in a resected tumor 10 months after treatment, 25% of which expressed PD-1. A patient with no response had no detectable E6 TCR T Cells in a resected tumor 3 months after treatment. Conclusions: E6 TCR T-cell therapy was safe at doses up to 2 x 1011 cells. Regression of metastatic HPV+ carcinoma occurred in two patients following treatment, suggesting that TCR T-cell therapy can mediate epithelial cancer regression. Clinical trial information: NCT02280811.