Diabetes associated with immune checkpoint inhibition: presentation and management challenges

Abstract Background In recent years, immune checkpoint blockade has become a standard therapy for a wide range of cancers. Adverse events, including endocrinopathies, result from the induction of autoimmunity. Case report We report a case series of nine individuals who presented with immunotherapy‐induced Type 1 diabetes between 2015 and 2017. Onset of diabetes occurred within 12 weeks of commencing therapy. Anti‐glutamic acid decarboxylase antibodies were present in six people. Retrospective testing of islet antibodies in pre‐treatment samples was possible in two people and this revealed anti‐glutamic acid decarboxylase seroconversion in the first and high anti‐glutamic acid decarboxylase titres pre‐ and post‐treatment in the second person. Six people had high risk human leukocyte antigen haplotypes. Clinical and genetic factors are described and compared with previously published cases. Conclusion This rare form of iatrogenic diabetes is a result of an accelerated, fulminant islet autoimmunity induced by immune checkpoint inhibitors. High risk human leukocyte antigen haplotypes have been found in the majority of cases. The role of pre‐existing islet autoantibodies as a biomarker is not yet known.