Introduction Immune checkpoint inhibitors (ICIs) have been used in patients with gynecologic cancers, but their efficacy is modest around 10~30% despite occurrence of a wide range of immune-related adverse events (irAEs). Several studies reported a correlation between the development of irAEs and the efficacy of ICIs in patients with various tumors. In this study, we aimed to investigate the relationship of immune-related diabetes mellitus (irDM) with efficacy of ICIs in patients with gynecologic cancers.

Methods We conducted a retrospective review of electronic medical records of 131 patients with gynecologic cancers who received different types of ICIs, such as pembrolizumab, durvalumab, and atezolizumab, on more than once, between 2018 and 2022. We evaluated progression free survival (PFS) and best objective response rate (ORR).

Results Five patients who received ICI treatment were identified to have developed irDM (ovarian cancer, n=3; cervical cancer, n=2). All patients received various types of ICIs, four receiving anti-PD1 inhibitors and one receiving both anti-PD-L1 inhibitor and anti-CTLA-4 inhibitors. The median PFS was 33 months (range 17–41), with an ORR of 100% including two patients with complete response and three with partial response. Only one patient experienced recurrence, with a PFS of 17 months. Four patients required hospitalization due to diabetic ketoacidosis but eventually recovered.

Conclusion/Implications Our findings suggest that there may be a relationship between the development of irDM and the efficacy of ICIs in patients with gynecologic cancer. However, further studies are needed to confirm this association and evaluate its underlying mechanisms.