Efficacy of olaparib combined with pembrolizumab in second-line treatment for extensive-stage small cell lung cancer

Abstract

Objective: To compare the efficacy and safety of olaparib in combination with pembrolizumab with pembrolizumab alone in second-line treatment for patients with extensive stage-small cell lung cancer (ES-SCLC) whose ages ranged from 40 to 80 years. Methods: From March 2017 to October 2019, 21 patients with progressed or relapsed small cell lung cancer after standard first line treatment were enrolled in this study. The olaparib/pembrolizumab group (n=11) was treated by olaparib 300mg twice per day combined with pembrolizumab 200mg once every 3 weeks, while pembrolizumab group was treated by pembrolizumab alone. Results: The objective response rate (ORR) of olaparib/pembrolizumab group and pembrolizumab group were 45.5% and 10.0%, respectively (P=0.149), and the disease control rate (DCR) were 81.8% and 70.0% (P=0.635). The median progression-free survival (PFS) were 5.93 months and 3.53 months (P=0.036), the median overall survival (OS) were 10.43 months and 8.43 months (P=0.063). The adverse reaction incidences of all grades were 90.9% and 70.0% (P=0.311), and the incidences of grade Ⅲ-Ⅴ including myelosuppression were 36.4% and 10.0% (P=0.311), gastrointestinal reaction were 9.1% and 10.0%, (P=1.000) and other immune-related adverse events were 18.2% and 30.0% (P=1.000). Further analysis showed the metastatic number (P=0.006), platinum sensitivity (P=0.036) and LDH level (P=0.022) significantly affected the ORR of olaparib/pembrolizumab therapy. Conclusion: Our preliminary study indicates that olaparib combined with pembrolizumab is an efficient and safe second-line treatment therapy for patients with ES-SCLC.