Higher doses of alpha-interferon do not increase the activity of the weekly cisplatin-interferon combination in advanced malignant mesothelioma.

Management of advanced malignant mesothelioma (MM) still requires innovative systemic therapy as its prognosis is poorly affected by currently available chemotherapy. The combination cisplatin and alpha-interferon (alpha-INF) has synergistic antitumoral activity in preclinical models and interesting activity in phase I-II clinical trials. Weekly CDDP (60 mg/m2) and alpha-IFN (3 MUI/d: d1-d4) in combination was tested in a previous phase I-II study in 23 MM patients, with a 36% objective response rate (ORR). A trial with higher doses of alpha-IFN in the same combination schedule was conducted to explore an incrementalist hypothesis. Thirty patients with MM received the same CDDP dose (60 mg/m2/w) and doubled doses of alpha-IFN (6 MUI/d: d1-d4). The treatment protocol consisted of two cycles of 4 weeks on/4 weeks off followed by two shorter cycles of 3 weeks on/3 weeks off, in the absence of life-threatening toxicity or progressive disease. All patients were evaluable for toxicity. The main treatment-limiting side-effects were digestive intolerance (nausea, vomiting) and severe asthenia. Antitumoral efficacy was not increased (ORR = 27%). Haematological and neurological toxicities were moderate and manageable. The antitumoral activity of the CDDP-alpha-IFN combination with higher doses of the latter is similar to our previous experience, but tolerance issues make it a poorer choice for eventual comparative trials, or as a standard therapeutic indication.