ADJUVANT ADAPTIVE IMMUNOTHERAPY WITH TUMOR-INFILTRATING LYMPHOCYTES AND MODULATED DOSES OF INTERLEUKIN-2 IN 22 PATIENTS WITH MELANOMA, COLORECTAL AND RENAL-CANCER, AFTER RADICAL METASTASECTOMY, AND IN 12 ADVANCED PATIENTS

Adoptive tumour infiltrating lymphocytes (TIL) in combination with a m odulated dosage of interleukin-2 (IL-2) can be used with acceptable to xicity in the treatment of immunogenic tumours. Following an experienc e of reinfusion in advanced melanoma, colorectal and renal cancer pati ents, treatment was given to disease-free patients after metastasectom y. The high risk of relapse and favour able ratio between reinfused TT L and possible microscopic residual disease determined this choice of adjuvant treatment. A group of 12 patients with advanced disease (7 me lanoma, 4 colorectal carcinoma, 1 kidney carcinoma) were treated with TIL (median 5.8x10(10) cells) and IL-2 (West's schedule) modulated tow ards a lower dosage (from 12 to 6 MIU/day) in order to maintain an acc eptable level of toxicity. As treatment was well tolerated, it was off ered to another 22 patients in an adjuvant setting after metastasectom y (11 melanoma, 10 colorectal carcinoma, 1 renal cancer), the median d ose of TIL reinfused being 4.95 x 10(10) cells. No objective response was observed in advanced patients: all patients progressed after a med ian of 1.5 months (0-8 months) and median survival was 8 months (3-22 months). Thirteen patients from the second group are still disease-fr ee after a median of 23+ months (9+-47+ months). The remaining 9 patie nts relapsed after a median of 5 months (3-18 months). Toxicity was mo derate as clinical and hepatic/renal function parameters were used to assess the need for dose reductions. Consequently, there was great div ersity in IL-2 dosages administered. In particular, there seemed to be a difference in IL-2 doses administered between disease-free cases an d those who progressed (17.5 MIU/day versus 7 MIL/day in melanoma pati ents; 11.2 MIU/day versus 7.1 MIU/day in colorectal cancer patients). By contrast, no differences were observed between number of TIL reinfu sed and clinical response. Phenotypical characteristics of reinfused T IL were similar to those reported in the literature: 97% were CD3 and 92% were CD8. Aspecific cytolytic activity was evaluated on 12 cases w hereas, in 2 melanoma cases, autologous tumour tissue was available fo r the specific cytotoxicity test. Perforin levels in TIL measured at t he end of culture were generally high or very high. Cytokine levels we re measured on the supernatant at the end of culture, with an estreme variability in results. Finally, zeta chain and p56(lck) were histolog ically assessed on the resected tissue from which TIL were cultivated. There were virtually none of the former and a complete absence of the latter, which concurs with data reported in the literature. The same immunocytochemical analysis was carried out on TIL at the end of cultu re. This time an almost complete restoration of both functions was see n, especially in melanoma patients, who are still free from disease. T he study is on-going and it has been decided to focus on disease-free patients after metastasectomy in order to increase the number and poss ibility of clinical and histological correlations.