The FDA today approved romiplostim for treatment of certain pediatric patients with immune thrombocytopenia, according to a press release from the agency.
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 common bleeding disorder in which blood does not clot as it should due to a low number of platelets or thrombocytes.
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 second study included patients diagnosed with ITP at least 6 months before enrollment.
Researchers randomly assigned patients 3:1 to romiplostim (n = 17) or placebo (n = 5).
Fifteen patients (88%) assigned romiplostim achieved a platelet count of 50 x 109/L or higher for 2 consecutive weeks and an increase in platelet count of 20 × 109/L or higher above baseline for 2 consecutive weeks during the treatment period. No patient assigned placebo achieved either of those thresholds.
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.