From the Tumor Immunology Section, Surgery Branch, National Cancer Institute, National Institutes of Health, Bethesda, MD
Authors disclosures of potential conflicts of interest are found at the end of this article.
Address reprint requests to Steven A. Rosenberg, MD, PhD, Head of the Tumor Immunology Section, Branch Chief, Surgery Branch, National Cancer Institute, National Institutes of Health, Building 10-CRC, Room 3-3940, 10 Center Drive, MSC 1201, Bethesda, MD 20892; e-mail: sar{at}nih.gov
Overview: For patients with melanoma, tumor-reactive lymphocytes can often be identified from melanoma biopsies, and these tumor-infiltrating lymphocytes (TILs) can be activated and numerically expanded. Initial studies with TILs administered to autologous patients, along with interleukin-2 therapy, demonstrated that TILs could mediate tumor regressions, but the clinical responses were generally short in duration and persistence of the transferred T cells was minimal. Studies in mouse models suggested that prior lymphodepletion could enhance adoptive cell therapy (ACT) and motivated the initiation of clinical trials combining lymphodepletion with ACT for the treatment of patients with refractory melanoma. ACT with tumor-reactive TILs in lymphodepleted patients in three sequential clinical trials resulted in objective responses in 52 of 93 patients (56%), including 13 complete responders. Some patients exhibited the persistence of high levels of transferred, tumor-reactive lymphocytes in their peripheral blood. The adverse effects of this treatment included transient marrow suppression caused by chemotherapy and the known consequences of interleukin-2 therapy. In these sequential trials, there was a trend toward better survival in patients who received increased intensity ablative regimens. Additional improvements could include simplification of the lymphocyte culture process, use of minimally cultured TILs that may persist longer in vivo, or genetically retargeted lymphocytes that recognize a wider array of cancer antigens; and by coadministration of lymphocyte-activating agents. ACT with lymphodepletion is a safe and potentially curative treatment for many patients with refractory melanoma.