CSEMO1 - A Case of Diabetic Ketoacidosis Due to Immunotherapy-induced Diabetes Mellitus

Abstract:

Background: Immunotherapy-induced diabetes mellitus is a rare endocrine adverse event associated with immune checkpoint inhibitor medications. We describe a case of immunotherapy-induced diabetes secondary to pembrolizumab, a programmed cell death receptor-1 inhibitor.

Case: A 78-year-old woman with metastatic endometrial cancer treated with pembrolizumab for the previous nine months presented with a one-week history of nausea, anorexia, and polydipsia. She was found to be in diabetic ketoacidosis with a venous blood pH of 7.14, random glucose of 32.0 mmol/L, beta-hydroxybutyrate of 9.78 mmol/L, and hemoglobin A1C of 8.5%. She had no personal or family history of diabetes, and her last hemoglobin A1C was 5.9% two years prior. She was treated with IV insulin and then transitioned to a basal-bolus insulin regimen. She had evidence of endogenous insulin deficiency, with a C-peptide of 66 pmol/L (325-1090 pmol/L) with fasting glucose of 12.3 mmol/L. After discussion with her oncologist, the patient was restarted on pembrolizumab since it had been effective at halting the progression of her cancer, and her immunotherapy-induced diabetes was an irreversible adverse event.

Discussion: As the use of immunotherapy agents increases, the incidence of immunotherapy-induced diabetes in adults is expected to rise. This case demonstrates the need for clear guidelines on glycemic monitoring while on these medications, and for patient education on the symptoms of hyperglycemia. The case also demonstrates the importance of individualized decision-making regarding the re-initiation of immunotherapy, considering the effectiveness of immunotherapy against the ongoing risk of further immune-related adverse events.