Endocrine Abstracts

JOINT2374

Introduction: Immune checkpoint inhibitors have changed the landscape of cancer therapy by targeting proteins that regulate immune checkpoints. However, their use is accompanied by adverse events, including endocrinopathies and diabetes mellitus (DM), which can be initially presented with diabetic ketoacidosis (DKA). We present here two cases of DKA in patients on immunotherapy for cancer.

Cases: 1: A 57-year-old man with not known DM and with non-small cell lung cancer, developed after 7 months on PD-1 checkpoint inhibitor (nivolumab), altered consciousness, tachypnea and vomiting. The laboratory findings, pH: 7.15, HCO3-: 11.8 mEq/l, blood glucose: 367 mg/dl and blood ketones >8 mmol/l, confirmed the diagnosis of DKA. He was managed with intravenous fluids and insulin with resolution of acidosis. Additional tests results included HbA1c:7.3%, negative anti-GAD, anti-islet and anti-insulin autoantibodies and a C-peptide:0.47 ng/mL. The patient was put on a 4 injection regimen and his blood glucose is well controlled. 2. A 52-year-old male, with no history of diabetes and bladder carcinoma, developed one month after starting PD-L1 checkpoint inhibitor (durvalumab), DKA with abdominal pain, polyuria and weight loss, pH: 7.09, HCO3-: 7.3 mEq/l, blood glucose: 436 mg/dL and HbA1c:9%. After hydration and insulin therapy, acidosis was restored within 24 hours. Anti-GAD, anti-islet and anti-insulin autoantibodies were negative and c-peptide:0,41 ng/ml. The patient was discharged on an intensified insulin regimen.

Discussion: DM is a rare but it can be a life-threatening complication of immunotherapy. Real world data show an incidence of 2% and a mean age of onset at 60 years. Initial presentation varies but in 70% of the cases, DKA is the presentation at diagnosis, due to rapid destruction of beta cells by the immune system. Due to the almost complete pancreatic beta cells’ destruction, ICI-DM is insulin-dependent. Doctors in charge of patients undergoing immunotherapy, should be on high alert, in order to recognize and treat on time this sudden and potentially life-threatening condition, optimising prognosis and minimizing disease complications.