Immune Checkpoint Inhibitors: Review and Management of Endocrine Adverse Events

In recent years, immune checkpoint inhibitors have emerged as effective therapies for advanced neoplasias. As new checkpoint target blockers become available and additional tumor locations tested, their use is expected to increase within a short time. Immune-related adverse events (irAEs) affecting the endocrine system are among the most frequent and complex toxicities. Some may be life-threatening if not recognized; hence, appropriate guidance for oncologists is needed. Despite their high incidence, endocrine irAEs have not been fully described for all immunotherapy agents available. This article is a narrative review of endocrinopathies associated with cytotoxic T lymphocyte-associated antigen-4, blockade of programmed death receptor 1 and its ligand inhibitors, and their combination. Thyroid dysfunction is the most frequent irAE reported, and hypophysitis is characteristic of ipilimumab. Incidence, timing patterns, and clinical presentation are discussed, and practical recommendations for clinical management are suggested. Heterogeneous terminology and lack of appropriate resolution criteria in clinical trials make adequate evaluation of endocrine AEs difficult. It is necessary to standardize definitions to contrast incidences and characterize toxicity patterns. To provide optimal care, a multidisciplinary team that includes endocrinology specialists is recommended. Implications for Practice: Immune checkpoint inhibitors are already part of oncologists' therapeutic arsenal as effective therapies for otherwise untreatable neoplasias, such as metastatic melanoma or lung cancer. Their use is expected to increase exponentially in the near future as additional agents become available and their approval is extended to different tumor types. Adverse events affecting the endocrine system are among the most frequent and complex toxicities oncologists may face, and some may be lifethreatening if not recognized. This study reviews endocrinopathies associated to immune checkpoint inhibitors available to date. Incidence, timing patterns, and clinical presentation are discussed, and practical recommendations formanagementare proposed.