Recombinant human thrombopoietin (rhTPO) of different dosing regimens for refractory/relapsed primary immune thrombocytopenia: a multicenter, randomized controlled trial and pharmacokinetics study.

What is the context? Relative thrombopoietin deficiency is implicated in primary immune thrombocytopenia (ITP), which is characterized by increased platelet destruction and impaired megakaryopoiesis.Patients who are innately unresponsive to or have relapsed after glucocorticoid treatment have limited treatment options.Recombinant human thrombopoietin (rhTPO) improves treatment response of primary ITP patients when added to high-dose dexamethasone.What is new? This trial sought to identify an optimal dosing regimen of rhTPO for patients who had failed or relapsed after glucocorticoid therapy.Of the 4 regimens, once daily 15000 U rhTPO for 14 injections yielded the greatest median increase in platelet count (167.5 × 10⁹/L) from baseline and attained the highest total response rate on day 14 (63.2%).30000 U rhTPO once every other day for 7 injections was effective in rapidly increasing platelet counts in the first 7 days.All 4 regimens were safe and well-tolerated.What is the impact? The 30000 U rhTPO once every other day regimen may offer an effective and safe regimen with less frequent injections, but future trials with longer follow-up are needed.