Abstract
BACKGROUND: Immune checkpoint inhibitors (ICIs) have shown significant improvements in patients with advanced non-small cell lung cancer (NSCLC). One of the major issues with ICIs is determining the optimal treatment duration. METHODS: This multicenter, retrospective study analyzed clinical outcomes in patients with NSCLC who completed 2 years of ICI therapy or were treated for more than 6 months and then discontinued ICIs without disease progression at 11 medical centers in Korea between August 2017 and December 2020. RESULTS: Ninety-six patients who completed 2 years of ICIs were reviewed. The median durations of treatment and follow-up were 24.0 and 33.9 months, respectively. The objective response rate (ORR) was 85.4%. The median progression-free survival (PFS) and overall survival (OS) periods were not reached. After completion, the PFS and OS rates were 81.1% and 96.4%, respectively, at 12 months. Forty-three patients were identified who discontinued ICIs without disease progression: 26 (60.5%) for adverse events and 17 (39.5%) for other causes. The median durations of treatment and follow-up were 10.5 and 21.2 months, respectively. The ORR was 90.7%. The median PFS and OS periods were not reached. After discontinuation, the PFS and OS rates were 71.0% and 90.0%, respectively, at 12 months. CONCLUSIONS: A significantly high proportion of patients who completed 2 years of ICI therapy continued to experience long-term PFS. Even if ICIs are discontinued after 6 months in patients without disease progression, they may achieve a durable response and facilitate long-term survival. LAY SUMMARY: The optimal treatment duration for immune checkpoint inhibitors (ICIs) remains to be determined. This study reports the long-term outcomes of patients with non-small cell lung cancer who completed 2 years of ICI therapy or achieved a durable response after the discontinuation of ICIs without disease progression in real-world practice. A significantly high proportion of patients who completed 2 years of ICIs continued to experience long-term progression-free survival. In addition, even if ICIs are discontinued after 6 months in patients without disease progression, they may achieve a durable response and facilitate long-term survival.