Continuous interleukin-2 and tumor-infiltrating lymphocytes as treatment of advanced melanoma. A national biotherapy study group trial

Abstract

Melanoma metastases were harvested from 82 patients for the purpose of growing and expanding tumor-infiltrating lymphocytes (TIL). Tumor tissue cell suspensions were incubated with interleukin-2 (IL-2), followed by repeated exposure to tumor antigen with or without OKT3 monoclonal antibody (MoAb). Initial growth success was achieved in 56 of 82 cultures (72%). Efforts were made to expand 26 of these 56 cultures for therapeutic TIL; 23 of 26 early cultures (88%) were successfully expanded for in vivo therapy. It took a mean of 78.5 ± 25.4 days to grow sufficient TIL for treatment. Therapy included cyclophosphamide (1 g/m²) on day 1, followed by a 96-hour continuous infusion of IL-2 (18 × 10⁶ IU/m²/d) on days 2 to 5, and approximately 10¹¹ (mean 1.49 ± 0.93 × 10¹¹) TIL on day 2. Patients who responded received monthly IL-2 as a 96-hour infusion. Median patient age was 45 years of age. Sixty-seven percent of the patients were men. Performance status was 0 to 1 in 77% of patients. Thirty-four percent of the patients had liver metastases. The usual IL-2 toxicities were seen. Response rate for 21 patients was 24% (95% confidence interval, 10% to 49%). One complete response was achieved with cells 98% CD4+; four partial responses were achieved with cells 80%, 94%, 98%, and 98% CD8+, respectively. Four of eight patients who received TIL, which had never been stimulated with OKT3, had tumor response. The authors conclude that a treatment plan for IL-2/TIL is technically difficult, costly, and effective for only a minority of patients. Overall, clinical results are not clearly superior to those obtained with other IL-2 regimens.