139P Gemcitabine as maintenance treatment of malignant pleural mesothelioma (GEMO): Randomized phase II study

Patients with malignant pleural mesothelioma have a median overall survival of approximately 1 year, and the feasibility of maintenance treatment is debatable in this setting. Unresectable malignant pleural mesothelioma has limited therapeutic options, with controversial data being present on the role of gemcitabine maintenance. We assessed the efficacy of gemcitabine maintenance versus best supportive care in patients with unresectable disease. This open-label, randomized phase II study included patients with histologically confirmed unresectable pleural mesothelioma who responded to 4–6 cycles of first-line chemotherapy (platinum+gemcitabine or platinum+pemetrexed). Group 1 received gemcitabine 1000 mg/ m2 IV in Days 1, 8 of a 21-day-long cycle until disease progression or unacceptable toxicity, and group 2 received best supportive care. Progression-free survival (PFS) at 6 months and overall survival (OS) at 18 months were evaluated using SPSS Statistics, version 22.0. A total of 64 patients were included (32 in each group). There was no difference in response rate to first-line chemotherapy between the groups (p = 0.209). PFS was better in group 1 than in group 2 (median 6.2 (95% CI, 4.7–7.6) vs 2.8 (1.8–3.9), p < 0.001). Among the clinical variables, only ECOG PS I status was associated with longer PFS (5.5 (95% CI, 4.6–6.4) vs 3.1 (2.4–3.7) for PS II, p < 0.001). OS did not differ significantly between the groups (23.3 (95% CI, 15.7–30.8) vs 13.4 (9.5–17.3, p = 0.155)). Patients who had a baseline prognostic nutritional index of >35 (p = 0.010), baseline PS I (p = 0.002), epithelioid vs non-epithelioid histology (p = 0.001), received pemetrexed in the first-line (p = 0.040), underwent not less than 6 cycles of chemotherapy (p = 0.006), received second-line treatment (p = 0.025) demonstrated better OS. Maintenance treatment with gemcitabine after first-line chemotherapy prolongs progression-free, but not overall survival in patients with malignant pleural mesothelioma.