Efficacy of pemetrexed plus a platinum rechallenge in the treatment of pleural mesothelioma

Introduction. Pemetrexed-based rechallenge therapies can be used as an option in the treatment of pleural mesothelioma. We aimed to investigate the efficacy of pemetrexed-based rechallenge in mesothelioma.Material and methods. A total of 132 patients who received chemotherapy for unresectable or metastatic pleural mesothelioma in the Medical Oncology Clinic of Dicle University Medical Faculty between 2005 and 2020 were included in our study. Pemetrexed plus platinum rechallenge treatments were compared with other chemotherapy regimens in terms of survival.Results. In our study, 31 (23.4%) of a total of 132 patients received rechallenge pemetrexed plus platinum treat- ment. There was no statistically significant difference between median progression-free survival of patients who received pemetrexed plus cisplatin or gemcitabine plus cisplatin in the first-line therapy [5 months vs. 8 months (HR = 1.43; 95% CI 0.59-3.45; p = 0.376)]. In the second-line treatment, patients who received rechallenge pemetrexed plus platinum therapy had statistically significantly higher median PFS than those who received gemcitabine plus platinum [6 months vs. 4 months (HR = 0.46; 95% CI 0.22-0.94; p = 0.011)] due to a previ- ous good response. In the second-line treatment, median overall survival was 15 months with gemcitabine plus platinum and 29 months with pemetrexed plus platinum rechallenge (p = 0.007).Conclusions. This study demonstrated that the pemetrexed plus platinum regimen was more effective than gemcitabine plus platinum in the second-line treatment in terms of both progression-free and overall survival in patients who had previously benefited from pemetrexed-based chemotherapy and had not progressed up to 6 months after first-line treatment.