FDA OKs Treatment for Immune Thrombocytopenia in Children

Officials with the FDA have approved romiplostim (NPLATE, Amgen) for the treatment of immune thrombocytopenia (ITP) in pediatric patients aged 1 year and older, according to a press release.

Romiplostim is indicated to treat patients with ITP for at least a 6-month duration who have had an insufficient response to other treatments, including corticosteroids, immunoglobulins, or splenectomy. It was previously granted orphan drug designation by the FDA.

The approval was based on 2 clinical trials including patients aged 1 year and older with ITP for at least 6 months. In 1 study, patients whose disease was refractory or relapsed after at least 1 prior ITP therapy received either romiplostim or a placebo. According to the data, durable platelet response, defined as at least 6 weekly platelet counts ≥ 50 × 10⁹/ during weeks 18 through 25 of treatment, was achieved in 52% of patients who received romiplostim and 10% who received a placebo. Overall platelet response was achieved in 71% and 20% of patients, respectively, according to the study.

For a median of 12 weeks, patients who received romiplostim had platelet counts ≥ 50 x 10⁹/L compared with 1 week in patients who received a placebo, according to the study.

In the second trial, patients diagnosed with ITP at least 6 months prior to enrollment received either romiplostim or a placebo. Fifteen patients who received romiplostim achieved a platelet count ≥ 50 x 10⁹/L for 2 consecutive weeks and an increase in platelet count of ≥ 20 × 10⁹/L above baseline for 2 consecutive weeks during the treatment period (88%, 95% CI: 64%, 99%). No patient receiving a placebo achieved either endpoint.

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The most commonly reported adverse events in pediatric patients included contusion, upper respiratory tract infection, and oropharyngeal pain.

Romiplostim is recommended at an initial dose of 1 mcg/kg administered as a weekly subcutaneous injection based on actual body weight in pediatric patients, according to the FDA. The agency also recommends adjusting the dose in increments of 1 mcg/kg until the patient achieves a platelet count ≥ 50 x 10⁹/L and reassessing body weight every 12 weeks.

Reference

FDA approves romiplostim for pediatric patients with immune thrombocytopenia [news release]. FDA’s website. https://bit.ly/2QVenIy. Accessed December 14, 2018.