Romiplostim, a thrombopoietin mimetic, increases platelet counts in patients with immune thrombocytopenia, with few adverse effects.

In this open-label, 52-week study (funded by Amgen), 234 adult patients with immune thrombocytopenia, who had not undergone splenectomy, were randomized to receive the standard of care or weekly subcutaneous injections of romiplostim.

The rate of a platelet response in the romiplostim group was 2.3 times that in the standard-of-care group.

Patients receiving romiplostim had a significantly lower incidence of treatment failure [11%] than those receiving the standard of care [30%].

Splenectomy also was performed less frequently in patients receiving romiplostim [9%]) than in those receiving the standard of care [36%].

The romiplostim group had a lower rate of bleeding events, fewer blood transfusions, and greater improvements in the quality of life.