Promacta (eltrombopag) has received orphan drug approval from the FDA to treat children 1 year old and up with a rare blood disorder called chronic immune thrombocytopenic purpura (ITP), provided they have not gotten “an appropriate response using other ITP medicines or surgery to remove the spleen. It should however only be used in patients with ITP whose degree of thrombocytopenia and clinical condition increase the risk for bleeding.
ITP is a disorder that results in an abnormally low number of platelets, the cells that help your blood clot. Without enough platelets, bleeding can occur under the skin, in mucous membranes (such as in the mouth) or in other parts of the body. Promacta has been designed to help increase blood platelet production, It is available as a tablet taken once-daily or as a powder that is mixed with liquid for children ages 1-5 to take orally. It was first approved in 2008 to treat adult patients with the same condition as the new pediatric indication.
“Today’s approval of Promacta emphasizes the FDA’s commitment to fully developing treatments in areas of pediatric hematology and oncology,” commented Richard Pazdur, M.D., director of the Office of Hematology and Oncology Products in the FDA’s Center for Drug Evaluation and Research. “This new use in ages 1 and up builds on a recent approval for ages 6 years and older, and fills an unmet need for young children whose disease has progressed after use of other available treatments.”
The efficacy and safety of Promacta in pediatric patients ages 1-17 years with chronic ITP was evaluated in two double-blind, placebo-controlled trials of 159 participants where the primary endpoint was an increase in platelet counts. In the first trial patients were randomly assigned to receive either Promacta or placebo daily for 7 weeks. 62% of those taking Promacta had an improvement in platelet counts without rescue therapy between weeks 1 and 6 compared to 32% in the placebo group. In the following trial, patients received either Promacta or placebo daily for 13 weeks. Those receiving Promacta, had a 41% increased platelet counts for at least 8 out of 8 weeks between weeks 5-12, compared to 3% percent of patients receiving a placebo. In both trials, patients taking Promacta also had less need for other treatments to increase their platelet counts, such as corticosteroids or platelet transfusions. In addition, among patients taking one or more ITP medications at the start of the trials, about half were able to reduce or discontinue their use of these medications, primarily corticosteroids.
The most common side effects of treatment with Promacta in children ages one and older were infections of the upper respiratory tract symptoms including fever, cough, nasal congestion, runny nose and sore throat, diarrhea, abdominal pain, rash and increase in liver enzymes.