Treatment of recurrent in transit metastases from cutaneous melanoma by isolation perfusion in extracorporeal circulation with interleukin-2 and lymphokine activated killer cells. A pilot study

Chemoresistant melanoma cells are known to be susceptible in vitro to lymphokine activated killer (LAK) cells. To obtain a high LAK/tumour cell ratio in vivo and avoid systemic toxicity due to interleukin-2 (IL-2), we used IL-2 plus LAK cells in the treatment of in transit melanoma metastases of the limbs by isolation perfusion (IP). In vivo immunological modifications induced by this immunotherapeutic approach were also analysed. Six patients previously treated with IP in extracorporeal circulation with tumour cytotoxic drugs and presently relapsing or not responding, were submitted to locoregional adoptive therapy consisting of 5 days systemic administration of IL-2 (Proleukin, EuroCetus) (9–12×10⁶ IU/m²/day c.i.). Autologous LAK cells were derived from leuka-pheresis and subsequent in vitro stimulation with IL-2; LAK cells were then given along with IL-2 (120–2400 IU/ml of perfusion priming) to the affected limb by IP. In addition, 7–16×10⁹ LAK cells were administered by systemic infusion the day after together with IL-2 (9–12×10⁶ IU/m²/day) c.i. for 5 days. All patients concluded the treatment without major toxicity. The analysis of circulating lymphocytes obtained from extracorporeal circuit at different times revealed rapid disappearance of LAK cells, suggesting their extravasation and/or endothelial adhesion in perfused tissues. Clinical responses included four partial and one complete response; another patient had stable disease. All patients are presently alive. Follow-up after IP ranges from 8 to 22 months.