Subcutaneous interleukin-2 in combination with medroxyprogesterone acetate and antioxidants in advanced cancer responders to previous chemotherapy: phase II study evaluating clinical, quality of life, and laboratory parameters.

We carried out an open, non-randomized phase II study including all patients treated with whatever chemotherapy or combined modality regimen for whatever cancer who were in clinical objective response (complete response, CR, or partial response, PR) or stable disease (SD). The treatment consisted of administration of recombinant interleukin-2 (rIL-2) at a dose of 1.8 MIU subcutaneously three times/week (every other day) for the first 2 weeks of every month plus medroxyprogesterone acetate (MPA) 500 mg/day every other day plus antioxidant agents alpha-lipoic acid 300 mg/day and N-acetyl cysteine 1800 mg/day or carbocysteine lysine salt oral solution 2.7 g/day. The treatment was administered for 1 year except when progression of disease occurred. The primary study endpoints were to define clinical outcome, i.e. duration of response, survival (overall survival, OS and progression-free survival, PFS), the toxicity profile, and the evaluation of quality of life (QL). As secondary endpoints, we measured the changes of lymphocyte count, serum levels of proinflammatory cytokines, IL-2, C-reactive protein (CRP) and leptin, blood levels of reactive oxygen species (ROS) and antioxidant enzymes (glutathione peroxidase, GPx and superoxide dismertase, SOD). From July 1998 to June 2003, 42 patients were enrolled in the study (M/F ratio, 39/3; mean age, 62.5 years). Twenty (47.6%) patients were elderly (> 65 years). The majority of patients had either head and neck cancer or lung cancer, 88% had locally advanced or metastatic disease at diagnosis, and 76% had ECOG 0. Forty patients were previously treated with chemotherapy (27 also with radiotherapy), two with IL-2 and interfiron (IFN), one with endocrine therapy and one with only surgery. We obtained an objective response to maintenance treatment of 50%. Median duration of response was 19 months and median PFS was 33 months. Median duration of maintenance treatment was 12 months, median follow-up duration from diagnosis to June 2003 was 40 months, and median follow-up duration from study entry to June 2003 was 17 months. The median overall survival has not been reached. Toxicity was negligible. As for QL, a significant improvement of cognitive functions was observed, whereas all other functioning and symptom scales did not change significantly. As for laboratory parameters, absolute lymphocyte count increased significantly, IL-6, IL-1 beta, tumor necrosis factor-alpha, CRP, and fibrinogen decreased significantly whereas IL-2 and leptin increased significantly after treatment. ROS decreased significantly, whereas GPx increased significantly after treatment. Patients alive at study end showed a significant increase in absolute lymphocyte count, IL-2, leptin, and GPx and a significant decrease of proinflammatory cytokines, CRP, fibrinogen, and ROS, whereas patients who died before study end exhibited only a significant increase in absolute lymphocyte count, IL-2, and GPx and a significant decrease of ROS. Long-term combined maintenance therapy with rIL-2 + MPA + antioxidant agents is feasible, has a very low toxicity, and results in the improvement of clinical outcome, QL, and laboratory parameters.