Background: In a prior Cancer and Leukemia Group B (CALGB) Phase II trial of patients with advanced, previously untreated mesothelioma, dihydro-5-azacytidine (DHAC) demonstrated a 17% response rate, including 1 complete response, with only mild myelosuppression. This Phase II study (CALGB 9031) was conducted to determine the effectiveness of and toxicities that would result from adding cisplatin to DHAC administered to the same patient population.
Methods: Thirty-six patients were treated with concurrent DHAC at 1500 mg/m2/day for 5 days by continuous infusion and cisplatin 15 mg/m2 daily for 5 days. Therapy was repeated every 3 weeks. Cisplatin was to be increased to 20 mg/m2 daily in subsequent cycles if toxicity was minimal. Therapy was continued until disease progression or excessive toxicity mandated discontinuation.
Results: Overall, 5 objective responses were observed in 29 evaluated patients (objective response rate, 17%). The median duration of response was 6.6 months. Median survival was 6.4 months, with a median time to clinical failure of 2.7 months. The major toxicity noted was significant chest/pericardial pain, as was observed with DHAC alone. There were 2 early deaths of unknown cause on Days 9 and 17 of therapy, respectively. Significant leukopenia was observed in 29% of patients, but there were no neutropenic fevers.
Conclusions: The addition of cisplatin to DHAC did not increase the response rate over that observed with DHAC alone in patients with mesothelioma; however, it did increase toxicity, especially leukopenia. This combination is not recommended for further studies involving mesothelioma patients.