Organ-specific immune-related adverse events and survival in patients with cancer with immune checkpoint inhibitors.

12124 Background: Immunotherapy with immune checkpoint inhibitors (ICIs) can lead to immune-related adverse events (irAEs). This study was designed to assess whether the occurrence of irAEs or different irAE characteristics correlates with survival outcomes in advanced cancer patients treated with ICIs. Methods: This cohort study included a panel of patients with advanced cancer who received ICI therapy at a single institute. Kaplan‒Meier curves were generated to describe progression-free survival (PFS) and overall survival (OS) in patients with irAEs or specific irAE characteristics. Results: A total of 238 patients were enrolled, and 83 (34.9%) patients developed at least one irAE. The irAE development was associated with prolonged OS (not reached vs 17.8 months, HR: 0.48, p < 0.001), PFS (8.7 vs 4.8 months, HR: 0.63, p = 0.003), and an improved objective response rate (24.1% vs 10.3%, p = 0.005). However, irAE characteristics, including severity, number of organs or systems affected, and timing of onset, were not associated with OS. Furthermore, we observed that only skin and endocrine toxicities independently protected against OS and PFS. Based on the results from organ-specific irAEs, the first development of skin or endocrine toxicities as protective irAEs rather than other irAEs was an independent indicator for predicting OS (HR: 0.24, p < 0.001) and PFS (HR: 0.43, p< 0.001). A prognostic irAE score based on organ-specific irAEs was developed to show the effect of total protective irAEs on patient outcomes. Conclusions: Not all irAEs are associated with prolonged survival. Identification of organ-specific irAEs but not other irAE characteristics is useful for stratifying patients who actually respond to and benefit from ICIs across different cancer types.