Endocrine Autoantibodies Determine Immune Checkpoint Inhibitor-induced Endocrinopathy: A Prospective Study

Incidence and awareness of endocrine-related adverse events (ERAE) associated with use of immune checkpoint inhibitors (ICI) has grown with increased ICI use, yet mechanisms for ERAE prediction, surveillance, and development are not well established. We prospectively evaluated the impact of endocrine autoimmunity on ERAE development and overall survival (OS). Adults ≥ 18 years of age prescribed ICI treatment for advanced or metastatic solid tumors and no known active/past endocrine disorders were eligible for enrollment. Thyroid, adrenal, and pancreatic antibodies as well as hormone levels were assessed prior to ICI treatment and at 8 to 9 weeks and 36 weeks after treatment for ERAE in relation to presence and changes in endocrine-specific antibodies, hormone levels, and OS. Sixty patients were enrolled and ERAE were detected in 14 (23.3%), with a median onset of 52 days (IQR, 38.5-71.5) after first ICI dose. Hypothyroidism occurred in 12 (20%) patients, and 2 (3.33%) patients developed hypophysitis. Diabetes and primary adrenal insufficiency were not observed. Antibodies were detected in 14 patients (11 at baseline, 3 developed during follow-up) and their presence was significantly associated with ERAE (R2 59.3%, P