Diabetic ketoacidosis induced by nivolumab in invasive mucinous adenocarcinoma of the lung: a case report and review of the literature.

Background: Nivolumab is the first programmed cell death receptor 1 (PD-1) inhibitor approved in China. Compared with chemotherapy, nivolumab has shown advantages of good efficacy and safety in the treatment of a variety of tumors. However, due to its short time of use in China and lack of safety experience, clinical understanding of its adverse reactions has not been sufficiently elucidated. In recent years, cases of diabetic ketoacidosis caused by nivolumab have been reported in the emergency department, which has aroused our concern.

Case Description: Here we present a serious case of diabetic ketoacidosis in a 69-year-old woman with invasive mucinous adenocarcinoma of the lung, which occurred following therapy with the PD-1 inhibitor nivolumab and dendritic cell/cytokine-induced killer cell (DC/CIK) immunotherapy. She presented with diabetic ketoacidosis 5 days after the second cycle of nivolumab administration. The patient presented with dry mouth symptoms, a maximum blood glucose of 511.2 mg/dL, hemoglobin A1c (HbA1c) level of 7.4%, urine ketone body value of 3+, and extracellular fluid residual alkali level of -3.8 mmol/L. Normal saline and insulin was initiated. The patient had no history of obesity or family history of diabetes. She received a single dose of 3.75 mg of dexamethasone treatment during this period of time which resulted in cough improvement, but did not explain the onset of the diabetes. She was treated with insulin, sitagliptin phosphate tablets and acarbose tablets. Diabetic ketoacidosis was considered an immune-related toxicity caused by nivolumab, and consequently, treatment with nivolumab was suspended. Patient was maintained under insulin treatment with a blood glucose levels normalization.

Conclusions: The incubation period of nivolumab-induced diabetic ketoacidosis is dispersive and the clinical risk is high. Patients need life-long insulin therapy. Blood glucose and HbA1c should be monitored routinely before and during nivolumab immunotherapy to avoid the occurrence of diabetic ketoacidosis. After the occurrence of diabetic ketoacidosis, insulin should be used to actively control blood glucose and do a good job in medication education to ensure long-term compliance of patients. Nivolumab should only be initiated if the patient has a clinical benefit under stable glucose control.