Endocrinological side-effects of immune checkpoint inhibitors

Three mAbs targeting immune checkpoint proteins are available for the treatment of patients with melanoma, lung, and kidney cancer, and their use will likely expand in the future to additional tumor types. We here update the literature on the incidence and pathophysiology of endocrine toxicities induced by these agents, and discuss management guidance. Immune checkpoint inhibition may trigger autoimmune syndromes involving different organs, including several endocrine glands (pituitary, thyroid, adrenals, and endocrine pancreas). Hypophysitis is more frequently associated with ipilimumab, whereas the incidence of thyroid dysfunction is higher with nivolumab/pembrolizumab. Primary adrenal insufficiency can rarely occur with either treatment. Autoimmune diabetes is very rare. As hypophysitis and adrenalitis may be life-threatening, endocrinological evaluation is essential particularly in patients developing fatigue and other symptoms consistent with adrenal insufficiency. Corticosteroids should be promptly used when hypophysitis-induced adrenal insufficiency or adrenalitis are diagnosed, but not in thyroiditis or diabetes. No impact of corticosteroids on the efficacy/activity of immune checkpoint-inhibiting drugs is reported. Hormonal deficiencies are often permanent. Summary. In absence of predicting factors, accurate information to patients provided by the oncology care team is essential for early diagnosis and to limit the consequences of checkpoint inhibition-related endocrine toxicity.