The U.S. Food and Drug Administration (FDA) approved romiplostim for the treatment of immune thrombocytopenia (ITP) in children younger than age 1 whose disease has had an insufficient response to corticosteroids, immunoglobulins, or splenectomy. Romiplostim initially was approved for the treatment of adult patients with ITP.
The decision to expand the drug’s indication was based on findings from two double-blind, placebo-controlled clinical trials in pediatric patients. In the first, patients with refractory or relapsed ITP were randomized 2:1 to receive romiplostim (n=42) or placebo (n=20). A greater proportion of romiplostim-treated patients than placebo recipients achieved a durable platelet response (at least 6 weekly platelet counts ≥50×109/L during weeks 18 through 25 of treatment): 22 patients (52%) vs. two patients (10%; p<0.05). Romiplostim treatment also led to a greater number of and more durable platelet responses, compared with placebo.
In the second study, patients were randomized 3:1 to receive romiplostim (n=17) or placebo (n=5). Fifteen romiplostim-treated participants (88%) achieved a platelet count ≥50×109/L and an increase in platelet count of ≥20×109/L above baseline that lasted for two consecutive weeks. No patient receiving placebo achieved either endpoint.
In both trials, the most common adverse events (AEs) in romiplostim-treated patients included contusion, upper respiratory tract infection, and oropharyngeal pain.
Romiplostim was approved with an orphan-product designation.
Source: FDA news release, December 14, 2018.