REACTIVATION OF A NORMAL ENDOGENOUS SECRETION OF INTERLEUKIN-2 IN METASTATIC CANCER-PATIENTS BY A CHRONIC SUBCUTANEOUS INJECTION OF INTERLEUKIN-2

It is known that advance cancer patients may show abnormally low level s of IL-2. The immunotherapy with IL-2 can induce objective tumor regr essions, but at present there are no data about the influence of a chr onic exogenous IL-2 administration on endogenous secretion of IL-2. Th is preliminary study was performed to evaluate whether a prolonged IL- 2 injection may be able to correct and eventual IL-2 endogenous defici ency in cancer patients. The study included 10 metastatic renal cancer patients, who underwent an immunotherapeutic cycle consisting of IL-2 at 6 million IU/day subcutaneously for 6 days/week for 4 weeks. Serum levels of IL-2 evaluated on venous blood samples collected before and 21 days after the end of IL-2 injection. Before the onset of treatmen t, abonormally low levels of IL-2 were seen in 6/10 patients. In patie nts with response or stable disease, mean levels of IL-2 observed 21 d ays after IL-2 cycle were significantly higher than those seen before therapy, whereas no difference occurred in those who progressed. This preliminary study would suggest that a prolonged subcutaneous injectio n of low-dose IL-2 may correct an eventual IL-2 endogenous deficiency in advanced cancer patients.