A BIOLOGICAL STUDY ON THE EFFICACY OF LOW-DOSE SUBCUTANEOUS INTERLEUKIN-2 PLUS MELATONIN IN THE TREATMENT OF CANCER-RELATED THROMBOCYTOPENIA

The production of cytokines involved in platelet generation, including interleukin (IL)-3, IL-6 and IL-11, is stimulated by IL-2. However, the platelet number has been shown to decrease on IL-2 cancer therapy, and this side effect depends on the enhanced peripheral platelet destruction following the activation of the macrophage system by IL-2 itself. Our previous studies showed that IL-2-induced macrophage activation may be counteracted by the pineal hormone melatonin (MLT). On this basis, a pilot study with IL-2 plus MLT was performed to evaluate its influence on the platelet number in cancer patients with persistent thrombocytopenia. The study included 20 advanced solid tumor patients, who received IL-2 at 3 million IU/day s.c. for 6 days/week for 4 weeks in association with MLT (40 mg/day orally). A normalization of the platelet number was achieved in 14/20 (70%) patients. This pilot study shows that the therapy with low-dose IL-2 plus MLT, in addition to its previously described antitumor activity, may also be effective in the treatment of cancer-related thrombocytopenia.