Autoimmune polyendocrine syndrome induced by immune checkpoint inhibitors: a systematic review

To summarize the clinical characteristics and immunological and genetic features of patients who developed autoimmune polyendocrine syndrome type II (APS-2) after treatment with immune checkpoint inhibitors (ICIs).

Several databases (MEDLINE/EMBASE/Cochrane) were searched for studies published between January 2000 and February 2020 involving patients with two or more endocrine disorders after ICI therapy.

Our final review included 22 articles comprising 23 patients (median age 56 years; 65.2% male patients). Of these patients, 60.9% received anti-programmed cell death 1 (PD-1) therapy, 17.4% received anti-programmed cell death ligand 1 (PD-L1) therapy, and 4.3% received anti-cytotoxic T-lymphocyte antigen 4 (CTLA-4) monotherapy. Patients underwent a median of four treatment cycles before the onset of the primary adverse event; the median time of onset was 8.5 weeks. Endocrine organs affected by ICI administration included the thyroid gland (18/23, 78.3%), pancreatic islets (17/23, 73.9%), pituitary gland (11/23, 47.8%), and adrenal gland (2/23, 8.7%). Related autoantibodies were detected in 65.2% of patients. In patients with diabetes, glutamic acid decarboxylase antibody was closely related to the development of diabetes ketoacidosis. The human leukocyte antigen genotype was reported in 34.8% (8/23) of patients, 5 (62.5%) of which had risk genotypes.

As a serious adverse event of ICI treatment, APS-2 is presented with abrupt initiation time and rapid development. Physicians should be aware of potential endocrine disorders and continue monitoring hormone status when treating cancer patients with ICIs.