Romiplostim for cancer treatment-induced thrombocytopenia in acute promyelocytic leukemia: a case report.

BACKGROUND: All-trans retinoic acid (ATRA) combined with arsenic trioxide (ATO) is a first-line treatment regimen for acute promyelocytic leukemia (APL), with generally milder myelosuppressive effects compared with conventional chemotherapy. Although standard-dose ATO is not typically considered a major risk factor for cancer treatment-induced thrombocytopenia (CTIT), severe and persistent thrombocytopenia may still occur during ATO maintenance therapy, and its clinical characteristics and therapeutic strategies remain unclear. CASE PRESENTATION: A 60-year-old female patient with APL developed refractory grade 3-4 thrombocytopenia during ATO maintenance therapy, with no significant response to recombinant human thrombopoietin or hetrombopag treatment (platelet nadir: 8 × 109/L; duration of platelet count <50 × 109/L: 8 weeks). Subsequently, romiplostim (250 μg/week) was administered, resulting in platelet recovery to 151 × 109/L within 3 weeks, accompanied by restoration of megakaryocyte numbers and reappearance of platelet-producing megakaryocytes in the bone marrow. The patient subsequently resumed maintenance therapy and completed the remaining treatment cycles with romiplostim support, maintaining continuous molecular remission during follow-up. CONCLUSION: This case suggests that refractory CTIT characterized by predominant megakaryocytic involvement may occur during ATO maintenance therapy, with clinical features potentially differing from those of conventional cytotoxic chemotherapy-related CTIT. Romiplostim may promote the recovery of residual megakaryopoietic capacity and provide a potential therapeutic option for such patients. However, its precise mechanism of action and the patient populations most likely to benefit require further investigation.