Outcomes with immune checkpoint inhibitors for relapsed small-cell lung cancer in a Swiss cohort.

Objectives: Early clinical trials showed promising outcomes with immune-checkpoint inhibitors (ICI) in a subset of patients with relapsed small-cell lung carcinoma (SCLC). The aim of this retrospective analysis was to assess the efficacy and safety of ICI for relapsed SCLC in a real-world patient population.

Methods: Nine cancer centres in Switzerland contributed data to this cohort. Responses were assessed by the local investigators using standard RECIST v1.1 criteria. Progression-free survival (PFS) and overall survival (OS) were analysed by the Kaplan-Meier method. Associations between potential predictive markers and survival endpoints were probed by Cox proportional hazards.

Results: Forty-five patients were included in the analysis. Median age was 63 years, 73% were males and 18% had an ECOG performance status (PS) ≥ 2. ICIs were given as second-line treatment in 60%. Twenty-four patients (53%) received ipilimumab with nivolumab. Twenty-eight patients (62%) had undergone irradiation (RT) prior to or during ICI. Overall response rate (ORR) was 29% and median PFS and OS were 2.3 and 6.5 months, respectively. Median duration of response was 9 months (95% CI 2.8-NA). Five patients maintained their response for > 6 months, all of them receiving combination treatment. There were no new safety signals.

Conclusion: This is the first report of "real-world" data on ICI in relapsed SCLC also including patients with poor PS. Promising durable responses were observed. No biological prognostic marker could be identified.