Treatment-free survival after two-year immune checkpoint inhibitor treatment in non-small cell lung cancer: Utilizing the Korean Health Insurance Review and Assessment Service database.

INTRODUCTION

Immune checkpoint inhibitors (ICIs) have improved survival in advanced non-small cell lung cancer; however, reimbursement is often limited to 2 years based on pivotal trial designs, raising concerns about disease control after cessation. We aimed to evaluate treatment-free survival (TFS), overall survival (OS), and new-onset comorbidities in patients completing 2 years of post-platinum ICI therapy using a nationwide Korean claims database.

METHODS

Using the Health Insurance Review and Assessment Service database, 10,275 patients initiating post-platinum ICI between 2017 and 2022 were identified. Patients treated for ≥2 years were classified as completers, and others were classified as discontinuers. Comorbidity rates were compared using person-years Poisson regression; landmark analysis at 2 years served as sensitivity analysis.

RESULTS

Of 10,275 patients, 786 (7.6%) completed 2 years of ICI therapy. Median TFS was 32.8 months; median OS was not reached. TFS did not differ significantly across ICI agents. Among discontinuers, 47.1% initiated subsequent therapy and 60.0% of untreated patients died within 42 days, suggesting most discontinuations were progression-related. Person-years analysis revealed lower comorbidity incidence rates in completers, including congestive heart failure (adjusted IRR, 0.430) and type 2 diabetes (0.581). Comorbidity onset was broadly distributed, with events occurring throughout follow-up, despite delayed median onset.

CONCLUSIONS

In this first large-scale Asian cohort study, 2-year ICI completion was associated with durable TFS and OS, and comorbidity rates were not increased in completers after person-years adjustment. However, broad temporal distribution of comorbidity onset warrants long-term survivorship surveillance.