Clinical characteristics and treatment efficacy of immune checkpoint inhibitors (ICIs) in patients with ICIs-induced Adrenal insufficiency

Background: Adrenal insufficiency (AI) caused by immune checkpoint inhibitors (ICIs) is an extremely rare immune-related adverse event (irAE). The detailed clinical characteristics and outcomes of patients with ICIinduced AI are unavailable. This study aimed to explore the clinical characteristics and efficacy of treatment in patients with ICI-induced AI. Methods: We retrospectively collected information on patients diagnosed with AI caused by ICIs at LiShui Municipal Central Hospital and Zhejiang Cancer Hospital, including baseline characteristics, laboratory results, symptoms, treatment outcomes of AI, and hormone use. Survival outcomes were calculated using the Kaplan-Meier method and stratified according to the different situations. Results: From December 2020 to February 2023, among 1014 patients treated with ICI therapy, a total of twenty patients were diagnosed with ICI-induced AI. Most of the patients were men (80%, n = 16), with a performance status (PS) of 0 - 1 (95%, n = 19). The median (range) age was 65.9 (49-80) years and 14 patients (70%) were treated with ICIs as first-line therapy. The majority of the patients (70%, n = 14) experienced grade 3 - 4 AI. All patients received corticosteroid replacement therapy, and only 7 patients recovered. The median time to the diagnosis of AI after starting ICI therapy was 5.2 (3.0 - 7.5) months. The objective response rate was 70% and median progression-free survival in these patients was 16.0 months (95% confidence interval: 11.7 - 20.3 months). Conclusions: ICI-induced AI is a rare irAE, and close monitoring of cortisol levels is important. Patients diagnosed with AI after receiving immunotherapy seem to have a favorable outcome.