[A prospective study of the efficacy and safety of maintenance therapy with recombinant human thrombopoietin in patients with primary immune thrombocytopenia: a multicenter study].

Objective: To evaluate the efficacy and safety of maintenance therapy with reduced dose of rhTPO in the patients with primary immune thrombocytopenia (ITP) who attained stable platelet (PLT) counts after daily administration of rhTPO. Methods: Treatment was started with a daily administration of rhTPO (300 U/kg) for 2 consecutive weeks. Patients who attained stable PLT≥50×10(9)/L were enrolled to maintenance therapy starting with every other day administration of rhTPO, then adjusted dose interval to maintain platelet count (30-100) ×10(9)/L. Results: A total of 91 eligible patients were enrolled. Fourteen patients discontinued the study due to noncompliance (12/14) and investigator decision (2/14) . Among 77 patients who completed the study, 38 patients with the administration of rhTPO at every other day or less could maintain PLT≥30×10(9)/L for 12 weeks. The percentage of patients with a platelet response (PLT≥30×10(9)/L) at 4(th) week, 8(th) week and 12(th) week of maintain therapy was 92.6% (63/68) , 82.7% (43/52) and 85.0% (34/40) , respectively. Median platelet counts remained in the range of (70-124) ×10(9)/L. The overall incidence of rhTPO-related adverse events was 7.7%. All the adverse events were generally mild. Conclusion: Extending the dose interval of rhTPO is feasible to maintain stable platelet count in the patients with ITP, but the optimal dose interval is uncertain and might vary with individuals.