Can Immune-related adverse events serve as clinical biomarkers of PD-1/PD-L1 inhibitor efficacy in Pan-Cancer Patients?

Abstract

Although PD-1/PD-L1 inhibitors are widely used as first-line treatment for patients with advanced tumors or as adjuvant therapy for patients with early-stage tumors, their efficacy is only 15–60%. Increasing evidence has demonstrated that biomarkers such as PD-L1 expression levels, microsatellite instability, and tumor mutation burden may assist in predicting the anti-tumor efficacy of PD-1/PD-L1 inhibitors. However, their clinical application value is limited, and there is currently a dearth of specific clinical markers to monitor or predict the efficacy of PD-1/PD-L1 inhibitors. Recently, studies have exposed that the efficacy of PD-1/PD-L1 inhibitors is positively correlated with immune-related adverse events (irAEs), suggesting that the latter may effectively predict anti-tumor efficacy. While there are controversies, a systematic understanding of the reasons and influencing factors of its correlation is still lacking. Therefore, this review aimed to introduce and discuss the latest research on the correlation between the efficacy of PD-1/PD-L1 inhibitors and irAEs. We identified that this positive correlation might be related to adipose tissue, T cells, pharmacokinetic characteristics, and antigen spread. In addition, the severity of irAEs, the duration of the use of PD-1/PD-L1 inhibitors, the comprehensive evaluation method of the severity of irAEs, and the genetic determinants are potentially the most significant bias factors when evaluating this correlation.