Nivolumab Retreatment in Non-Small Cell Lung Cancer Patients Who Responded to Prior Immune Checkpoint Inhibitors and Had ICI-Free Intervals (WJOG9616L).

PURPOSE: To explore the efficacy of retreatment with immune checkpoint inhibitors (ICI) in patients with advanced non-small cell lung cancer (NSCLC) who responded to prior ICI and had adequate ICI-free interval. PATIENTS AND METHODS: Patients with advanced NSCLC who had achieved complete response (CR), partial response (PR), or stable disease for ≥6 months with prior ICI therapy preceding progression were prospectively enrolled. All patients should have had ICI-free interval ≥60 days before registration. Patients were treated with nivolumab (240 mg) every 2 weeks until progression. The primary endpoint was overall response rate (ORR). Secondary endpoints included progression-free survival (PFS), overall survival, and safety (Trial Identifier, UMIN000028561). RESULTS: Sixty-one patients were enrolled during October 2017 to February 2020, with 59 analyzed for efficacy. Regarding prior ICI, 41 patients had CR or PR. Median treatment on ICI and median ICI-free intervals were 8.1 months and 9.2 months, respectively. Twenty patients experienced immune-related adverse events (irAE) that required discontinuation of prior ICI. Nivolumab retreatment demonstrated ORR of 8.5% [95% confidence interval (CI), 2.8-18.7%] and median PFS of 2.6 months (95% CI, 1.6-2.8 months) while 5 responders had 11.1 months of median PFS. In the multivariate analysis, ICI-free interval was the only predictive factor of PFS (HR, 2.02; P = 0.02), while prior efficacy or history of irAE was not. Common adverse events were skin disorders (23%), malaise (20%), and hypoalbuminemia (15%). CONCLUSIONS: Even in patients who initially responded to prior ICI and had ICI-free interval, once resistance occurred, retreatment with nivolumab had limited efficacy.