PHASE-II STUDY OF A SHORT-COURSE OF WEEKLY HIGH-DOSE CISPLATIN COMBINED WITH LONG-TERM ORAL ETOPOSIDE IN PLEURAL MESOTHELIOMA

Background: In a previous phase II study with a dose-intensive weekly cisplatin schedule for six cycles, we observed a partial response in 5 of 14 patients with pleural mesothelioma. However, response duration was short (median 6 months). Since oral etoposide may theoretically be synergis tic to cisplatin, we performed a phase II study with the combination of both drugs. Patients and methods: Twenty-five chemo-naive patients with pleural mesothelioma were treated with cisplatin 70 mg/ m(2) days 1-8-15 and days 29-36-43 in combination with oral etoposide 50 mg days 1-15 and days 29-43. Patients with stable disease, or better, continued treatment with oral etoposide 50 mg/m(2)/day days 1-21 every 28 days. Results: All patients were evaluable for response and toxicity. Complete response was observed in one patient and partial responses in 5 patients (RR% 24%; 95% Cl: 10%-45%) for a median duration of 30 weeks. Twelve patients had stable disease. The response status never improved during maintenance treatment with oral etoposide. Most patients tolerated the regimen very well. Toxicity was mainly haematologic with leukocytopenia causing treatment delays in 8 patients. Ototoxicity grade 1 or 2 was observed in 8 patients, neurotoxicity grade 1 in 9 patients and nephrotoxicity grade 1 in 1 patient. Conclusion: Frequently administered cisplatin in combination with oral etoposide has a moderate but definite activity in pleural mesothelioma.