FDA approves thrombopoiesis-stimulating agent

Amgen Inc. and FDA on August 22 announced the approval of romiplostim, or Nplate, a drug that directly stimulates the bone marrow to produce platelets. FDA said it approved the drug for use only by patients with chronic immune thrombocytopenic purpura who have not responded sufficiently to current treatments, such as splenectomy or corticosteroid or immunoglobulin therapy. In addition, the FDA-approved labeling states that romiplostim should be used only in patients with immune thrombocytopenic purpura whose low platelet count and clinical condition increase the risk for bleeding. The drug should not be used to normalize a patient’s platelet count. Doses of romiplostim, a thrombopoietin-receptor agonist, are to be administered once weekly by subcutaneous injection. The labeling recommends an initial dose of 1 μ g of drug per kilogram of actual body weight. Thereafter, the dose is to be increased in increments of 1 μ g/kg until the patient’s platelet count is at least 50 × 109/L. No dose should exceed 10 μ g/kg.