Neuroimmunotherapy of advanced solid neoplasms with single evening subcutaneous injection of low-dose interleukin-2 and melatonin: preliminary results.

On the basis of the demonstrated existence of immunoneuroendocrine interactions and on the previously observed synergistic action between the pineal hormone melatonin (MLT) and interleukin-2 (IL-2), we have designed a neuroimmunotherapeutic combination consisting of low-dose IL-2 and MLT in the treatment of advanced solid neoplasms. The study included 24 patients with advanced solid tumours (non-small cell lung cancer 9; colorectal cancer 7; gastric cancer 3; breast cancer 2; cancer of pancreas 1; hepatocarcinoma 1; unknown primary tumour 1), 21 of whom showed distant organ metastases. Not all patients responded to previous chemotherapies, or had tumours for which no standard therapy was available. Moreover, not all patients were able to tolerate IL-2 immunotherapy at the conventional doses. IL-2 was given subcutaneously at a dose of 3 x 10(6) U/day at 8:00 p.m. for 6 days/week for 4 weeks. MLT was given orally at a dose of 50 mg at 8:00 p.m. every day, starting 7 days before IL-2 injection. In non-progressed patients, a second cycle was given after a 21-day rest period. A partial response was seen in 3/24 patients (lung 2; stomach 1; duration: 11, 4, 4 months, respectively). Moreover, a minimal response (duration: 8+ months) was seen in 1 lung cancer patient. Stable disease was obtained in 14/24 patients (median duration: 6+ months), while the remaining 6 patients progressed. An improvement in performance status was seen in 7/24 patients. No important toxicity was observed. Mean eosinophil and lymphocyte levels significantly increased during the immunotherapy, and their rise was significantly higher in patients with response or stable disease than in those with progressive disease. These preliminary results show that neuroimmunotherapy with low-dose IL-2 and the pineal hormone MLT is a biologically active and well tolerated strategy, capable of determining an apparent control of tumour growth in patients with advanced solid neoplasms, for whom no standard effective therapy is available.