Safety and Efficacy of Re-treating with Immunotherapy after Immune-Related Adverse Events in Patients with NSCLC

Considering retreatment following recovery from an immune-related adverse event (irAE) is a common clinical scenario, but the safety and benefit of retreatment is unknown. We identified patients with advanced non-small cell lung cancer (NSCLC) treated with anti-PD-(L)1 who had treatment held due to irAEs and divided them into two groups: those retreated with anti-PD-(L)1 (retreatment cohort) or those who had treatment stopped (discontinuation cohort). Out of 482 NSCLC patients treated with anti-PD-(L)1, 68 (14%) developed a serious irAE requiring treatment interruption. Of these, 38 (56%) were retreated and 30 (44%) had treatment discontinued. In the retreatment cohort, 18 (48%) patients had no subsequent irAEs, 10 (26%) had recurrence of the initial irAE, and 10 (26%) had a new irAE. Most recurrent/new irAEs were mild (58% grade 1-2) and manageable (84% resolved or improved to grade 1). Two treatment-related deaths occurred. Recurrent/new irAEs were more likely if the initial irAE required hospitalization, but the initial grade and time to retreatment did not influence risk. Among those with no observed partial responses prior to the irAE, progression-free survival (PFS) and overall survival (OS) were longer in the retreatment cohort. Conversely, for those with objective responses prior to the irAE, PFS and OS were similar in the retreatment and discontinuation cohorts. Among patients with early objective responses prior to a serious irAE, outcomes were similar, whether or not they were retreated. Together, data suggest that benefit may occur with retreatment in patients with irAEs who had no treatment response prior to irAE onset. Cancer Immunol Res; 6(9); 1093-9. ©2018 AACR.