Pembrolizumab-Induced Aplastic Anemia Successfully Treated With Thrombopoietin Receptor Agonist in a Patient With Lung Adenocarcinoma: A Case Report and Literature Review.

A 71-year-old female with postoperative recurrence of lung adenocarcinoma was treated with chemotherapy plus immunotherapy (carboplatin, pemetrexed, and pembrolizumab). On day eight after the first cycle, she presented with fever and loss of appetite. Laboratory tests showed severe pancytopenia. Bone marrow biopsy revealed hypocellular marrow consistent with aplastic anemia (AA), which is considered an immune-related adverse event (irAE). Treatment with pulse glucocorticoid (GC) therapy, granulocyte colony-stimulating factor, and cyclosporine had a limited effect. On day 24, eltrombopag, a thrombopoietin receptor agonist, was started, subsequently leading to gradual hematologic recovery and discharge on day 34. IrAE-induced AA has a poor prognosis, with no established standard treatment. This case demonstrates the potential of thrombopoietin receptor agonists as a therapeutic option in GC-resistant irAE-induced AA.