Comparison of cisplatin plus pemetrexed and cisplatin plus gemcitabine for the treatment of malignant pleural mesothelioma in Japanese patients

Background: Cisplatin plus pemetrexed is a standard front-line chemotherapeutic regimen for inoperable malignant pleural mesothelioma (MPM). However, no clinical trials have compared the efficacy of cisplatin plus pemetrexed and cisplatin plus gemcitabine, which may be comparable based on previous phase II study results. This study aimed at evaluating the efficacy of cisplatin plus pemetrexed and comparing it with that of cisplatin plus gemcitabine in Japanese MPM patients. Methods: From July 2002 to December 2011, 13 and 17 consecutive patients with inoperable MPM were treated with cisplatin plus gemcitabine and cisplatin plus pemetrexed, respectively, at the Shizuoka Cancer Center. We reviewed the medical charts of these patients and evaluated their characteristics as well as data regarding drug toxicity and antitumor efficacy. Results: The response rates were 15% and 35% in the cisplatin plus gemcitabine and cisplatin plus pemetrexed groups, respectively (P=0.4069), while disease control rates were 77%, and 82%, respectively (P=0.9999). Progression-free survival was significantly higher with cisplatin plus pemetrexed (median, 215.5 days) than with cisplatin plus gemcitabine (median, 142.5 days) (P=0.0146; hazard ratio [HR], 0.3552). Overall survival showed a tendency towards being superior with cisplatin plus pemetrexed (median, 597.5 days) compared with cisplatin plus gemcitabine (median, 306.5 days) (P=0.1725, HR, 0.5516). Hematological toxicities, especially thrombocytopenia and neutropenia, tended to be more frequent and severe in the cisplatin plus gemcitabine group. Conclusions: Cisplatin plus pemetrexed may be superior and should continue to be the standard front-line chemotherapeutic regimen for inoperable MPM. (C) 2013 The Japanese Respiratory Society. Published by Elsevier B.V. All rights reserved.