A 60-year-old Japanese man, with no medical or family history of diabetes, presented with acute-onset type 1 diabetes following nivolumab treatment for advanced non-small-cell lung cancer. During cycle 35 of nivolumab therapy, his glycated hemoglobin level increased from 7.6% to 9.1% in one month. Test results for islet-related and anti-thyroid peroxidase antibodies were negative. A glucagon tolerance test showed insulin dependency. Type 1 diabetes after anti-programmed death-ligand 1 antibody administration is an immune-related adverse event, and numerous reports suggest that fulminant type 1 diabetes can develop in these patients. However, there are few reports of acute-onset type 1 diabetes mellitus.
Keywords: HbA1c; irAE; lung cancer; nivolumab; type 1 diabetes mellitus.