Incidence and Timing of Immune-Related Adverse Events in Immune-Checkpoint Inhibitor-Treated Patients: A Retrospective Observational Study.

Abstract

Immune-checkpoint inhibitors (ICIs) are effective against various cancers; however, immune-related adverse events (irAEs) have been reported and the timing and risk factors are unknown. Therefore, we examined the incidence and timing of irAE occurrence. Patients who received ICIs at our hospital between 1 April 2016 and 31 March 2020 were enrolled. Patients were classified into an irAE group or non-irAE group. In addition, we examined the onset time and symptoms of irAEs for each ICI type. A total of 80 patients received ICIs, of which 27 (33.8%) developed irAEs. The incidence of irAEs was 35.3% for nivolumab, 35.5% for pembrolizumab, and 28.6% for atezolizumab. The incidence of pneumonitis was 12.5%, 8.8% for dermatologic adverse events, and 6.3% for thyroid dysfunction. The earliest case of onset was after the 1st course, and the latest cases occurred after the 66th course. By the sixth course, 69% of the irAEs occurred. The positive rates for anti-thyroid peroxidase and anti-thyroglobulin antibodies were higher in the irAE group compared to the non-irAE group. Our findings suggest a high probability of irAEs occurring early in ICI treatment, with a diverse range of symptoms. This underscores the need for vigilant monitoring and tailored patient management during the initial courses of ICI therapy.