Recurrent endometrial carcinoma with immune-mediated thrombocytopenia following durvalumab: A case report.

The use of immune checkpoint inhibitors (ICIs) has expanded the therapeutic landscape for advanced or recurrent endometrial carcinoma. Durvalumab-a programmed death-ligand 1 (PD-L1) inhibitor-demonstrated clinical benefit in the 2023 DUO-E trial when combined with carboplatin and paclitaxel. Immune thrombocytopenia (ITP) is an uncommon but potentially life-threatening immune-related adverse event (irAE). A 73-year-old woman with recurrent endometrial carcinoma developed severe ITP after three cycles of paclitaxel, carboplatin, and durvalumab. Fourteen days after cycle 3 she presented with pyelonephritis, bacteremia, and acute disseminated intravascular coagulation (DIC). Despite infection control, her platelet count declined to 1 × 10/μL, with epistaxis, hematuria, and melena. Suspecting ITP as an irAE, intravenous immunoglobulin (IVIG 10 g/day × 5 days) and high-dose intravenous prednisolone (1 mg/kg/day) were administered. Platelet counts improved gradually to 85 × 10/μL by hospital day 32, and she was discharged on a steroid taper. This appears to be the first Japanese report of durvalumab-associated ITP in endometrial carcinoma. Clinicians should maintain a high index of suspicion for ITP when unexpected thrombocytopenia or bleeding occurs during durvalumab therapy and initiate prompt treatment.