The FDA has approved a supplemental Biologics License Application (sBLA) for romiplostim (Nplate, Amgen) to expand treatment with romiplostim to newly diagnosed and persistent adult with immune thrombocytopenia (ITP), a rare, serious autoimmune disease characterized by low platelet counts, who have had an insufficient response to corticosteroids, immunoglobulins, or splenectomy.

The approval followed an open-label, single-arm Phase 2 trial that included approximately 75 adult patients with ITP diagnosed less than 6 months prior to the baseline who had an insufficient response to a first-line treatment, such as corticosteroids. The median time from ITP diagnosis to study enrollment was 2.2 months.

The median number of months with platelet response (≥ 50 x 109/L) was 11 months during the 12-month treatment period (95% CI: 10, 11), with a median time to first platelet response of 2.1 weeks (95% CI: 1.1, 3.0). Additionally, 93% of patients achieved 1 or more platelet responses during the 12-month treatment period.

On the secondary endpoint, 32% of patients achieved remission for at least 6 months, defined by maintaining a platelet count ≥ 50 x 109/L in the absence of romiplostim and any medication for ITP

According to the National Heart, Lung, and Blood Institute, ITP is a bleeding disorder in which the blood does not clot as it should. It is thought to be caused by an autoimmune response.2

In December 2018, the FDA approved another sBLA for romiplostim for the treatment of pediatric patients with ITP.

The safety profile of romiplostim was similar across patients, regardless of ITP duration. The participants experienced the following adverse events: bronchitis, sinusitis, vomiting, arthralgia, myalgia, headache, dizziness, and more. The adverse reaction of thrombocytosis occurred with an incidence of 2% in adults with ITP duration up to 12 months.

Reference
  1. Nplate® (romiplostim) Now Approved For Earlier Use In Adults With Immune Thrombocytopenia [press release]. PR Newswire website. Published October 18, 2019. https://www.prnewswire.com/news-releases/nplate-romiplostim-now-approved-for-earlier-use-in-adults-with-immune-thrombocytopenia-300941074.html. Accessed October 18, 2019.
  2. Immune Thrombocytopenia. NIHLBI website. https://www.nhlbi.nih.gov/health-topics/immune-thrombocytopenia. Accessed October 18, 2019.