LAUSR

Advanced malignant melanoma (MM) is treated with immune checkpoint inhibitor (ICI) therapy, which often results in several immune-related adverse events. Fulminant type 1 diabetes mellitus (T1DM) is a rare, rapidly progressive, life-threatening disease. Here, we summarize 8 cases of MM with ICI-induced T1DM and describe one case that developed fulminant T1DM due to nivolumab therapy. We retrospectively reviewed patients treated with ICI from 2014 to 2021 at our hospital. The clinical features and risk factors of ICI-induced T1DM were discussed. ICIs were administered to 426 MM patients at our hospital. Among these, nivolumab was administered in 5 cases, pembrolizumab in 1 case, and the combination of nivolumab and ipilimumab in 2 cases. The frequency of ICI-associated T1DM was 1.88%. The mean glycated hemoglobin level at T1DM onset was 8.0 ± 1.0%. Of the patients, 75% were diagnosed with fulminant T1DM, 62.5% developed diabetic ketoacidosis, and 25% had glutamic acid decarboxylase (GAD) antibodies (an early predictive marker for T1DM). The mean interval between the first ICI administration and T1DM development was 201 ± 187 days. The mean duration of resumption was 13 ± 7 days. We should monitor for T1DM development following treatment with ICIs. ICI can be continued to be used to treat MM if insulin therapy successfully controls T1DM. A 67-year-old patient who received adjuvant nivolumab therapy developed fulminant T1DM and thyrotoxicosis 57 days later and tested positive for GAD antibodies. Subsequently, he developed hypophysitis and an isolated adrenocorticotropin deficiency. He continued receiving nivolumab along with self-injected insulin without developing recurrence.