After the cessation of immune checkpoint inhibitor (ICI) therapy due to an immune-related adverse event (irAE), it remains unclear whether retreatment with ICI is more effective than its discontinuation. To explore the clinical significance of its retreatment, patients with non-small cell lung cancer (NSCLC) who had treatment interruption of nivolumab due to irAEs were identified and the clinical differences between discontinuation and retreatment with nivolumab were retrospectively reviewed.

49 (26%) of 187 patients treated with nivolumab experienced the cessation of treatment due to a serious irAE. Retreatment was chosen in 21 patients (retreatment cohort), while 28 patients discontinued treatment (discontinuation cohort).

The most common irAEs requiring treatment cessation in 49 patients included pneumonitis (59.2%), adrenal insufficiency (8.2%), liver dysfunction (8.2%) renal dysfunction (8.2%), colitis (6.1%), hypothyroidism (4.1%), and rash (2.0%). The frequency of grade 3 or 4 initial irAEs did not differ between the retreatment and discontinuation cohorts; however, the incidence of renal dysfunction and colitis was higher in the retreatment cohort than in the discontinuation cohort. Retreatment with nivolumab displayed an overall response rate of 15%, without a significant increase in irAEs. The median overall survival and progression-free survival did not differ significantly between the retreatment and discontinuation cohorts, irrespective of the efficacy of prior nivolumab.

Retreatment exhibited a slightly higher efficacy without a significant increase in irAEs; however, the clinical significance of retreatment and discontinuation was similar in NSCLC patients that led to treatment interruption due to any irAE after initial nivolumab.