Phase I Study of Adoptive T-Cell Therapy Using Antigen-Specific CD8+ T Cells for the Treatment of Patients With Metastatic Melanoma

Abstract

Purpose: The adoptive transfer of in vitro generated tumor antigen-specific cytotoxic T lymphocytes (CTL) provides a promising approach to the immunotherapy of cancer. A phase I study was conducted to test the feasibility, safety, and survival of adoptively transferred Melan-A–specific CTL lines in melanoma patients. Patients and Methods: Eleven HLA-A2⁺ patients with metastatic melanoma received at least three intravenous infusions of Melan-A–specific CTL at 2-week intervals. CTL were generated by four rounds of in vitro stimulation of purified CD8⁺ peripheral blood lymphocytes with autologous dendritic cells pulsed with an HLA-A2 binding Melan-A peptide. Each T-cell infusion was accompanied by a 6-day course of low-dose interleukin-2. Results: A total of 52 T-cell infusions were administered, averaging 2.1 × 10⁸ Melan-A–specific CTL per infusion. Clinical adverse effects were mild and consisted of chills and low-grade fever in seven of 11 patients. Clinical and immunologic responses revealed an antitumor response in three of 11 patients (one complete regression, one partial regression, one mixed response), an elevated frequency of circulating Melan-A tetramer⁺ T cells up to 2 weeks in all the patients with a maximal frequency of 2% of total CD8⁺ T cells, an increase in eosinophils to up to 50% in seven of 11 patients, and a selective loss of Melan-A expression in lymph node metastases in two evaluated patients after T-cell transfer. Conclusion: Our data indicate that the adoptive transfer of antigen-specific T cells in melanoma patients can induce clinical tumor-specific immune responses without major adverse effects.