Efficacy and safety of sintilimab in combination with chemotherapy for recurrent extensive-stage small cell lung cancer: a real-world retrospective study

Background: Immune checkpoint inhibitors (ICIs) no longer are approved for second-line or later treatment of extensive-stage small cell lung cancer (ES-SCLC), and have not been studied in combination with chemotherapy. Exploring the efficacy and safety of second-line or later immunotherapy for ES-SCLC is an urgent clinical question that needs to be addressed, and combination therapies are an important research direction. This study intended to investigate the efficacy and safety of the sintilimab in combination with chemotherapy as a second-line and beyond treatment option for ES-SCLC. Methods: Medical records of patients who received treatment with sintilimab in combination with chemotherapy or chemotherapy alone as a second-line or beyond therapy were retrospectively analyzed. The study evaluated efficacy and safety. Indicators of efficacy included objective response rate (ORR), disease control rate (DCR), progression-free survival (PFS), and overall survival (OS). Safety indicators included adverse events (AEs). Results: This cohort comprised of 46 patients: 24 in the sintilimab combination chemotherapy group and 22 in the chemotherapy group. Chemotherapy received by both groups was either albumin-bound paclitaxel or irinotecan. Compared with the chemotherapy group, the sintilimab combination chemotherapy group had higher ORR and DCR (ORR: 37.5% vs. 9.1%, P=0.04; DCR: 75.0% vs. 40.9%, P=0.04), and significantly prolonged PFS and OS [median PFS (mPFS): 5.07 vs. 2.45 months, P=0.006; median OS (mOS): 14.43 vs. 10.34 months, P=0.009]. Also, there was no significant increase in the incidence of AEs in the sintilimab combination chemotherapy group, which was well tolerated by patients. Conclusions: Sintilimab in combination with chemotherapy is superior to single-agent chemotherapeutic treatment as second-line or later therapy in ES-SCLC patients who have not received prior immunotherapy. These results need to be confirmed in future clinical trials.