Effective Treatment of Refractory Aplastic Anemia with Romiplostim after Failure of Multiple Thrombopoietin Receptor Agonists: A Single-Center Retrospective Study

Background: Romiplostim (ROMI), a second-generation thrombopoietin receptor agonist (TPO-RA), has shown promising results in patients with refractory aplastic anemia (AA); however, its optimal dosage, efficacy, and safety in patients with refractory AA who experienced treatment failure with immunosuppressive therapy (IST) and other types of TPO-RAs remain unclear. In the present study, we aimed to retrospectively assess the efficacy and safety of high-dose ROMI (with an initial dosage of 20 μg/kg per week) in these patients.

Patients and methods: Patients who received ROMI consecutively for at least 3 months between April 8, 2023 and October 23, 2023, and were followed up for at least 6 months after therapy were analyzed. All enrolled patients had failed to respond and stopped the previous treatments for at least 3 months before receiving ROMI.

Results: Eleven patients were followed up for at least 6 months; all experienced treatment failure with IST and at least two types of other TPO-RAs. They had a median age of 54 years (range: 27–77 years), and eight (72.7%) were women. The patients' initial and maximal ROMI dose was 20 μg/kg per week. At a median follow-up of 8 months (range, 6–8 months), 72.7% (8/11) of the patients reached the response criteria at a median of 1 month (range: 1–3 months). Of these patients, 54.5% (6/11) met the criteria for a complete response at a median of 2.5 months (range: 1–3 months), and 27.3% (3/11) achieved a trilineage response. No severe ROMI-related adverse events that led to treatment discontinuation or dosage reduction were observed. Notably, 12.5% (1/8) of the responders relapsed at 5 months after stopping ROMI for 2 months.

Conclusion: High-dose ROMI with an initial dosage of 20 μg/kg per week is effective and safe for patients with refractory AA who experienced treatment failure with IST and multiple oral TPO-RAs, exerting a rapid response.