Romiplostim Approved to Treat Pediatric Patients with Immune Thrombocytopenia

The U.S. Food and Drug Administration has approved Amgen’s romiplostim to treat pediatric patients ages 1 year and older with immune thrombocytopenia (ITP) for a minimum of six months and who have had an insufficient response to corticosteroids, immune globulin or splenectomy.

Approval was based on two double-blind placebo-controlled clinical trials in pediatric patients 1 year and older with ITP for at least six months. In one study, patients whose disease was refractory or relapsed after at least one prior ITP therapy were randomized to receive romiplostim or placebo. Durable platelet response (at least six weekly platelet counts greater than or equal to 50 Å~ 109/L during weeks 18 through 25 of treatment) was achieved in 22 patients (52 percent) who received romiplostim and two (10 percent) on the placebo arm. Overall platelet response, defined as a durable or a transient platelet response, was achieved in 30 (71 percent) and four (20 percent) patients, respectively. Patients who received romiplostim had platelet counts greater than or equal to 50 x 109/L for a median of 12 weeks, compared to one week in patients who received placebo. The results for all three endpoints were statistically significant, with p-values all less than 0.05.

In the other study, patients diagnosed with ITP at least six months prior to enrollment were randomized to receive romiplostim or placebo. Fifteen patients who received romiplostim achieved a platelet count of greater than or equal to 50 x 109/L for two consecutive weeks and an increase in platelet count of greater than or equal to 20 Å~ 109/L above baseline for two consecutive weeks during the treatment period. No patient receiving placebo achieved either endpoint.

In pediatric patients, the most common adverse reactions included contusion, upper respiratory tract infection and oropharyngeal pain.