THU374 Fulminant Type 1 Diabetes Mellitus And DKA Secondary To Pembrolizumab

Disclosure: I. Iqbal: None. M. Khan: None. M. Ahmad: None. R. Mehreen: None. Introduction: Pembrolizumab is a programmed cell death receptor (PD-1) binder on T cells, which promotes their activation against cancer cells. It can also cause unwanted T cell activation against the body’s own cells, leading to type 1 diabetes mellitus (DM1), among other autoimmune phenomena. We are reporting a case of a new onset pembrolizumab-induced fulminant DM1 who presented with diabetic ketoacidosis (DKA). Despite the emerging data on immune checkpoint inhibitors (ICPI), fulminant DM1 with DKA in a previously nondiabetic patient is still uncommon. Case Presentation: A 66-year-old female with a history of recurrent metastatic non-small cell lung cancer (NSCLC) presented to the emergency room (ER) with an extensive itchy rash. She was enrolled in a clinical trial for NSCLC, where she received immunotherapy with pembrolizumab for five months. Rash was treated outpatient for scabies, with no improvement. She was then started on prednisone 40mg daily and betamethasone 0.05% cream. She applied the cream daily but took prednisone orally for only one day, after which she could not tolerate it due to anxiety and restlessness. She ran out of betamethasone three days before coming to ER. On admission, vitals were: Heart rate 90 beats per minute, blood pressure 119/95 mmHg, respirations 20/minute. The exam showed flushed cheeks, red and dry macules on the skin with excoriations, and dry mucus membranes. Random blood glucose levels (BSL) were 660mg/dl. Labs were; HCO3 16mmol/L, Beta-hydroxy butyrate 20mmol/L, anion gap 17mmol/L, Hemoglobin A1c: 5.6%. For DKA, we started an insulin drip. Workup revealed very low C-peptide levels of 0.2ng/ml, with a concomitant BSL of 500mg/dL. Anti-islet cell and anti-glutamic acid decarboxylase antibodies (anti-GAD) were positive with levels of 0.04 nmol/L and 0.07 nmol/L, respectively. Once she stabilized and the anion gap closed, she was transitioned to subcutaneous insulin and discharged on 42 units of Lantus, along with 12 units of premeal Lispro and sliding-scale insulin. She was removed from the clinical trial due to complications. Unfortunately, she got readmitted with influenza A, Staphylococcus aureus bacteremia, and another episode of DKA, complicated with respiratory failure, and she decided on hospice. The patient passed away after two days. Conclusion: Immune-related adverse event of new-onset fulminant DM1, leading to DKA, is a serious and potentially fatal complication of pembrolizumab. For patients receiving pembrolizumab, who have uncontrolled BSL, we suggest checking the anti-islet cell and anti-GAD antibody levels and DKA risk stratification to allow the timely initiation of insulin and prevent further complications. Presentation: Thursday, June 15, 2023