Immune Checkpoint Inhibitor-Associated Diabetes Mellitus: A Single-Institution Experience

OBJECTIVE To characterize immune checkpoint inhibitor-associated diabetes mellitus (ICI-DM) in a single-institution case series. DESIGN AND METHODS Retrospective chart review of 18 patients with new-onset ICI-DM following anti-PD-1/anti-PD-L1 therapy for advanced carcinomas. RESULTS 9/18 patients had diabetic ketoacidosis (median glucose: 27.92mmol/L; median glucose before presentation: 6.35mmol/L). Median C-peptide at ICI-DM diagnosis was low, and declined during follow-up. Median anti-PD-1/anti-PD-L1 duration before ICI-DM was 3.65 months (range 0.56-12.23). Time to ICI-DM onset was a median 1.4 months/3 ICI cycles and 6 months/10 cycles in those positive and negative for GAD65 autoantibodies, respectively. Time to ICI-DM onset was a median 2.5 months/3 ICI cycles and 4.8 months/8 cycles after anti-PD-L1 or anti-PD-1 therapy, respectively. Significant pancreatic atrophy was seen radiographically. CONCLUSIONS ICI-DM presents abruptly, appears irreversible, is characterized by pancreatic atrophy, and may occur both earlier following PD-L1 blockade compared to PD-1 inhibition and in those who have positive GAD65 autoantibodies.