Four versus Six Cycles of Pemetrexed/Platinum as a First Line Treatment of Malignant Pleural Mesothelima: Results of a Randomized Phase II Study

Background: Pemetrexed-platinum is the standard first line treatment of patients with malignant pleural mesothelioma (MPM). Optimal number of pemetrexed-platinum chemotherapy cycles is not yet known with certainty. Aim: To compare 4 cycles versus 6 cycles of pemetrexed-platinum regimen as a 1st line treatment in MPM. Methods: This was a randomized phase II study (1:1) which was conducted at a single institution. Arm A received 4 cycles of pemetrexed-platinum, while Arm B received 6 cycles. The 1ry outcome of the current study was overall survival. It was assessed through Kaplan-Meier survival estimates as well as a multivariate Cox regression model adjusted for other relevant baseline clinicopathological characteristics. Results: A total of 60 patients were included into the current study (30 in each arm). Kaplan-Meier survival analysis according to the number of cycles of chemotherapy did not reveal a significant survival difference between both subsets (p = 0.194). Multivariate Cox regression analysis for factors affecting overall survival did not show an overall survival difference based on treatment arm (p = 0.105). Conclusions: Six cycles does not appear to improve the overall survival of MPM patients compared to four cycles. Shorter course of treatment should be considered in resource-limited settings like Egypt.