Immune-related adverse events: promising predictors for efficacy of immune checkpoint inhibitors.

Purpose: This study was designed to investigate the correlation between immune-related adverse events (irAEs) of immune checkpoint inhibitors (ICIs) and corresponding efficacy, and to explore the potential of predicting the efficacy of ICIs via irAEs.

Methods: Electronic databases including PubMed, Embase, Cochrane Library, CNKI and Wanfang were applied to search for relevant studies. The primary endpoint was overall survival (OS) or progression-free survival (PFS), and the secondary endpoint was objective response rate (ORR). Stratification analyses were conducted according to the type of irAEs and ICIs, region of studies and primary tumors. Furthermore, statistical analyses were realized by means of RevMan 5.3 software.

Results: Altogether, 40 studies with 8,641 participants were enrolled, among which the incidence of irAEs ranged from 15.34 to 85.23% and the major sites reached out to skin, endocrine organ, gastrointestinal tract, liver and lung. The ORR, OS and PFS in irAE group were significantly higher than those in non-irAE group as per pooled analyses and stratification analyses. Importantly, patients with irAEs in skin, endocrine organ or gastrointestinal tract rather than in liver and lung were found to obtain survival benefits (p < 0.05).

Conclusion: IrAEs, especially in skin, endocrine organ or gastrointestinal tract, triggered by ICIs indicate significant survival benefits.