Background: Immune checkpoint inhibitors (ICIs) have emerged as promising therapeutic agents in non-small cell lung cancer (NSCLC). However, the duration for which ICIs should be continued remains a clinical problem.
Methods: We examined the efficacy of anti-PD-1/PD-L1 inhibitors after the discontinuation of antibodies due to adverse events (AEs) in patients with NSCLC. This was a multicenter retrospective study that analyzed NSCLC patients who were treated with PD-1/PD-L1 inhibitors by August 2016.
Results: The patients with NSCLC were 18 males and 1 female at a median 67 years of age (range: 49-80 years). Eighteen of 19 patients were treated with nivolumab, one was with atezolizumab. Approximately half of AEs were interstitial pneumonia. Fourteen patients (73.7%) were treated with steroid therapy. The median number of treatment cycles was 7 (range, 1-70), and the median duration of treatment was 2.8 months (range, 1 day-32.9 months). The overall response rate with confirmation during treatment was 21.1%. The median progression-free survival (PFS) was 10.2 months (95% confidence interval [CI] = 3.2-17.1 months) and 5.6 months (95% CI = 0-12.2 months) from the initiation and the discontinuation of PD-1/PD-L1 treatment, respectively. The median PFS after discontinuation according to the confirmed response during administration was not reached for partial response (PR) and 4.9 months (95% CI, 3.7-6.0) for stable disease (SD) patients (P = 0.02).
Conclusion: The PFS of the PR patients was completely different from that of the SD patients. The cases with PR prior to the onset of AE tended to show a durable response after the discontinuation of PD-1/PD-L1 inhibitors.
Keywords: Adverse event; Anti-PD-1/L1 inhibitor; Discontinuation; Non-small cell lung cancer.