Comparison of the Immune Checkpoint InhibitorFree Survival Between Patients Who Completed and Those Who Discontinued ICI for Non-Small Cell Lung Cancer.

Abstract

Background: Immune checkpoint inhibitors (ICI)-containing therapy for advanced or recurrent non-small cell lung cancer (NSCLC) are not completed by some responders for reasons other than progressive disease (PD). The proportion of patients who discontinue ICI and the length of their treatment-free status are unclear.

Methods: In this single-center retrospective study, we examined the medical records of 233 patients who initiated ICI-based therapy at our hospital between 2016 and 2020. We identified patients who completed treatment and discontinued it for reasons other than PD. The primary outcome was treatment-free survival, which we termed ICI-free survival.

Results: Sixty-five patients were eligible for analysis. In the discontinuation group, the median duration of ICI was 3.9 months. Median progression-free survival, ICI-free survival, and overall survival in the entire population were 25.0, 11.5, and 78.3 months, respectively. The ICI-free survival rates at 1, 2, and 3 years were 48%, 38%, and 36%. The Kaplan-Meier curve of ICI-free survival almost reached a plateau 2 years after ICI termination. The median ICI-free survival for the completion group and discontinuation group was not reached and 9.4 months, respectively (adjusted HR 0.28, p = 0.01). Estimated ICI-free survival rates in the completion and discontinuation groups were 80% vs. 38% at 1 year, 66% vs. 30% at 2 years, and 66% vs. 28% at 3 years.

Conclusion: Patients who discontinued ICI therapy had poorer ICI-free survival than those who completed it. However, there was a notable population of patients with long-term ICI-free survival.