Thyroid abnormalities following the use of cytotoxic T-lymphocyte antigen-4 and programmed death receptor protein-1 inhibitors in the treatment of melanoma

ContextCheckpoint inhibitors are emerging as important cancer therapies but are associated with a high rate of immune side effects, including endocrinopathy. ObjectiveTo determine the burden of thyroid dysfunction in patients with melanoma treated with immune checkpoint inhibitors and describe the clinical course. Design and patientsConsecutive patients with melanoma treated with either ipilimumab, nivolumab, pembrolizumab or the combination of ipilimumab and nivolumab were identified. Baseline thyroid function tests were used to exclude those with pre-existing thyroid abnormalities, and thyroid function tests during treatment used to identify those with thyroid dysfunction. ResultsRates of overt thyroid dysfunction were in keeping with the published phase 3 trials. Hypothyroidism occurred in 130% treated with a programmed death receptor-1 (PD-1) inhibitor and 222% with a combination of PD-1 inhibitor and ipilimumab. Transient subclinical hyperthyroidism was observed in 130% treated with a PD-1 inhibitor, 159% following a PD-1 inhibitor, and 222% following combination treatment with investigations suggesting a thyroiditic mechanism rather than Graves' disease, and a high frequency of subsequent hypothyroidism. Any thyroid abnormality occurred in 230% following ipilimumab, 391% following a PD-1 inhibitor and 50% following combination treatment. Abnormal thyroid function was more common in female patients. ConclusionThyroid dysfunction occurs commonly in patients with melanoma treated with immune checkpoint inhibitors, with rates, including subclinical dysfunction, occurring in up to 50%.