Cancer immunotherapy with low-dose interleukin-2 subcutaneous administration: potential efficacy in most solid tumor histotypes by a concomitant treatment with the pineal hormone melatonin.

The antitumor efficacy of IL-2 is limited to renal cancer and melanoma. Several cytokines have been associated with IL-2 in an attempt to improve its activity, without, however, any clear benefit. Recent experimental and clinical studies have suggested the possibility to manipulate the host biological response by immunomodulating neurohormones, such as the pineal hormone melatonin (MLT). On the bases of these considerations, we have designed a neuroimmunotherapeutic protocol with low-dose IL-2 subcutaneous therapy (3 million IU/day for 6 days/week for 4 weeks) plus MLT (40 mg/day orally, starting 7 days before IL-2) in advanced solid neoplasms other than renal cancer and melanoma, which are generally resistant to IL-2 alone. The study included 82 patients, 72 of whom showed distant organ metastases. Tumor histotypes were, as follows: non-small cell lung cancer: 19; hepatocarcinoma: 16; colon cancer: 15; gastric cancer: 11; cancer of pancreas: 11; breast cancer: 6; miscellaneous: 4. Objective tumor regression were achieved in 17/82 (21%) patients, consisting of CR in 4 (liver: 2; pancreas: 1; stomach: 1) and PR in 13 (lung: 4; liver: 4; stomach: 2; pancreas: 1; breast: 1; colon: 1). The median duration of response was 8+ months. A stabilization of disease was obtained in 30 patients, while the other 35 patients progressed. The lack of progression was associated with a significantly higher increase in lymphocyte and eosinophil mean number and with a significantly lower increase in neopterin mean levels. The treatment was well tolerated in all patients.(ABSTRACT TRUNCATED AT 250 WORDS)