Increased Lymphocyte Proportions as a Candidate Biomarker for Immune-Related Adverse Events in Patients Treated With Immune Checkpoint Inhibitors and Chemotherapy

Background

Combination therapy comprising immune checkpoint inhibitors (ICIs) and chemotherapy is standard treatment for many cancer types. However, the management of adverse events (AEs) induced by combination therapy is more complicated than that of AEs induced by ICI monotherapy. Although immune-related AEs (irAEs) induced by ICIs and AEs induced by chemotherapy require distinct therapeutic approaches, distinguishing between them can be challenging. Therefore, in this exploratory study, we aimed to investigate whether lymphocyte proportion could serve as a candidate biomarker associated with the occurrence of irAEs in patients receiving ICI plus chemotherapy combination therapy. Patients and methods: We categorized 122 patients into the irAE group (those who experienced irAEs), chemo-AE group (those with chemotherapy-induced AEs), and non-AE group (those without AEs) and analyzed their lymphocyte proportions before one course (baseline sample) and two courses (two-course sample) of treatment.