Retreatment with pemetrexed-based chemotherapy (PBC) in patients with malignant pleural mesothelioma (MPM): An observational study.

Abstract

e18106 Background: The role of second-line therapy in MPM patients (pts) is currently undefined. Recent case series have suggested a possible role of re-treatment PBC. Aim of this study was to evaluate this therapeutic option in a consecutive series of pts previously treated with first-line PBC. Methods: Pts with partial response (PR) or stable disease (SD) for at least 3 months after first-line PBC were eligible for the study. Pts receiving retreatment with PBC either as second-line (2L) or further-line (> 2L) therapy were considered. Results: 34 pts were retrospectively evaluated (2L: 20 pts; > 2L: 14 pts). Median age was 65 (range 36-81). EORTC prognostic score was poor in 19 pts, good in 12, not available in 3. In 2L setting 1 RC, 5 PR, 9 SD were observed, whereas 1 SD was observed in > 2L, for an overall disease control rate (DCR) of 47%. 17 pts (50%) had progressive disease (2L: 4 pts; > 2L: 13 pts). Median progression free survival (mPFS) was 3.1 mo (1.1-24.3 mo). Pts receiving PBC as 2L therapy had a longer mPFS (4.8 vs 2.1 mo; p < 0.001). Pts with a good EORTC score had a longer mPFS (4.1 vs 2.8 mo; p.02). Median overall survival (OS) was 10,1 mo (1.8-49.2 mo). Overall survival (OS) and PFS after re-treatment with PBC were correlated to first-line progression time (FLPT) (FLPT < 6 mo, 6-12 mo, > 12 mo, OS was 2.6 vs 7.8 vs 14.8 mo; PFS was 1.4 vs 2.7 vs 4.8 mo; p < 0.01). A longer OS was observed in pts with a good EORTC score (p.02), in pts receiving PBC as 2L therapy (p.02) and achieving a DC (p < 0.002). Grade 3/4 haematological toxicity was observed in 5 pts (14.7%). Nonhematological toxicity was mild, with 1 case of grade 3 constipation. Conclusions: Re-treatment with PBC seems to be a possible option in the second-line setting in MPM pts achieving a durable DC with first-line treatment. Further evaluation in a prospective trial is warranted. No significant financial relationships to disclose.