Patients With Antithyroid Antibodies Are Prone To Develop Destructive Thyroiditis by Nivolumab: A Prospective Study

Context Immune checkpoint inhibitors, including anti-programmed cell death-1 (PD-1) antibodies, have become promising treatments for a variety of advanced malignancies. However, these medicines can cause immune-related adverse events (irAEs), including endocrinopathies. Objective This study examined the incidence of endocrine irAEs induced by nivolumab. Patients and Main Outcome Measured Sixty-six patients treated with nivolumab at Nagoya University Hospital were prospectively evaluated for pituitary hormones, thyroid function, antithyroid antibodies (Abs), and glucose levels every 6 weeks after the initiation of nivolumab for 24 weeks. Results Four out of 66 patients developed destructive thyroiditis, and three patients developed hypothyroidism requiring levothyroxine replacement. The prevalence of positive anti-thyroglobulin Abs (TgAbs) and/or anti-thyroid peroxidase Abs (TPOAbs) at baseline was significantly higher in the group that developed destructive thyroiditis (3/4) compared with the group that did not develop thyroiditis (3/62; P = 0.002). There were no significant differences in other clinical variables between the groups. There were no endocrine irAEs other than destructive thyroiditis during the 24 weeks. The prevalence of TgAbs and/or TPOAbs at baseline was not associated with the development of other irAEs, including pneumonitis, colitis, or skin reactions. Conclusions Our real-world data showed that destructive thyroiditis was an endocrine irAE that was frequently induced by nivolumab and was significantly associated with positive TgAbs and/or TPOAbs before treatment. Our findings indicate that evaluating these Abs before treatment may help identify patients with a high risk of thyroidal irAEs and may have important clinical benefit.