Abstract
Immune checkpoint inhibitor-induced type 1 diabetes mellitus (ICI-T1DM) is a rare adverse reaction associated with durvalumab. Among the adverse reactions to durvalumab, the incidence of new-onset diabetes is relatively rare, occurring in ~0.2% of cases. The present study reports the case of a 62-year-old woman who developed ICI-T1DM following two cycles of durvalumab, presenting with thirst, polydipsia and polyuria. Laboratory examinations (glycated hemoglobin and glutamic acid decarboxylase antibody), along with consultations from an endocrinologist, led to the patient being diagnosed with ICI-T1DM. Immunotherapy was discontinued, and insulin replacement therapy was initiated. Blood glucose levels were closely monitored using a subcutaneous meter. The onset of diabetic ketoacidosis (DKA) was prevented due to timely treatment. In conclusion, medical oncologists need to be aware that durvalumab, an immunotherapy agent, can induce ICI-T1DM. Therefore, regular monitoring of blood glucose levels and collaborative consultations with endocrinologists are essential for an accurate diagnosis when elevated blood sugar levels are detected. The prompt diagnosis of ICI-T1DM is crucial to prevent the occurrence of DKA.