Romiplostim for the treatment of chronic immune thrombocytopenia in adult Japanese patients: a double-blind, randomized Phase III clinical trial

The efficacy and safety of romiplostim, a thrombopoietin-mimetic peptibody, were evaluated in a double-blind, placebo-controlled, randomized trial of Japanese patients with chronic immune thrombocytopenia (ITP). Thirty-four ITP patients received romiplostim (n?=?22) or placebo (n?=?12) for 12?weeks, with a starting romiplostim dose of 3?μg/kg weekly. The primary end point was the number of weeks with platelet response, defined as a platelet count ≥50?×?10(9)/L (not including the 4?weeks after rescue medication administration). Patients received a median of 4 (range 1-19) prior ITP therapies including splenectomy in 44%. On study, 68% also received concomitant ITP therapy. Weekly responses occurred for a median of 11?weeks with romiplostim as compared to 0?weeks with placebo (p?10%) in romiplostim-treated patients included nasopharyngitis, headache, peripheral edema, back pain, and extremity pain. In conclusion, romiplostim significantly increased and maintained platelet counts and was well tolerated in Japanese patients with ITP.