Aggravation of diabetes, and incompletely deficient insulin secretion in a case with type 1 diabetes‐resistant human leukocyte antigen DRB1*15:02 treated with nivolumab

Anti‐programmed cell death‐1 (PD‐1) antibody therapy induces various adverse effects, especially in the endocrine system. Several cases of acute‐onset insulin‐dependent diabetes after anti‐PD‐1 antibody therapy have been reported. Many of these cases have a susceptible human leukocyte antigen (HLA) genotype for type 1 diabetes, possibly suggesting that HLA might be involved in the onset of diabetes with anti‐PD‐1 therapy. We describe an atypical case of hyperglycemia after anti‐PD‐1 antibody administration. A 68‐year‐old Japanese man with pancreatic diabetes and steroid diabetes was given nivolumab three times for chemoresistant adenocarcinoma of the lung. On day 5 after the third infusion of nivolumab, he had hyperglycemia (blood glucose 330 mg/dL and hemoglobin A1c 8.0%) without ketosis and with incompletely deficient insulin secretion. The patient had both type 1 diabetes susceptible (HLA‐A*24:02 and ‐DRB1*09:01) and resistant (HLA‐DRB1*15:02) HLA genotypes. These HLA genotypes differ from those previously reported in anti‐PD‐1 antibody‐induced diabetes, and might have influenced the preservation of insulin secretion after nivolumab administration in the present case.