The FDA approved romiplostim for treatment of pediatric patients with immune thrombocytopenia. The approval of romiplostim (Nplate, Amgen) applies to children aged 1 year or older who have had immune thrombocytopenia (ITP) for at least 6 months and had insufficient response to corticosteroids, immunoglobulins or splenectomy.
ITP is a disorder that can lead to easy or excessive bruising and bleeding. The bleeding results from unusually low levels of platelets — the cells that help blood clot. The disorder affects children and adults, although children often develop ITP after a viral infection and usually recover fully without treatment. In adults, the disorder is often long term.
The FDA based the approval on results of two double-blind, placebo-controlled clinical trials, both of which included patients aged 1 year or older who had ITP for at least 6 months.
One study included children whose disease relapsed after or was refractory to at least one prior ITP therapy. Researchers randomly assigned these patients 2:1 to romiplostim (n = 42) or placebo (n = 20).
A higher percentage of patients assigned romiplostim achieved durable platelet response (52% vs. 10%; P < .05), defined as at least six weekly platelet counts of 50 × 109/L or higher between week 18 and week 25 of treatment.
A higher percentage of romiplostim-treated patients also achieved overall platelet response (71% vs. 20%; P < .05), defined as durable or transient platelet response.
Patients in the romiplostim group achieved platelet counts of 50 x 109/L or higher for a median 12 weeks, whereas patients assigned placebo attained that platelet count level for a median 1 week (P < .05).
The most common adverse reactions reported among at least 25% of pediatric patients treated with romiplostim include contusion, upper respiratory tract infection and oropharyngeal pain.
The FDA previously granted the agent orphan drug designation for this indication.
