The FDA has recently expanded its approval of the blood-platelet-boosting drug Promacta. Now doctors can prescribe the drug to children as young as one year, who have not responded to other medications or surgery.

Promacta is used to treat patients suffering from a rare blood disorder known as chronic Immune Thrombocytopenic Purpura (ITP). Those suffering from ITP have abnormally low platelet counts, which can lead to bleeding under the skin,  in the mucous membranes, or other parts of the body.

“Today’s approval of Promacta emphasizes the FDA’s commitment to fully developing treatments in areas of pediatric hematology and oncology,” said 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 one and up builds on a recent approval for ages six years and up, and fills an unmet need for young children whose disease has progressed after use of other available treatments.”

The expanded approval follows two double-blind, placebo-controlled trials of 159 participants, where researchers were looking for an increase in platelet count.

The first trial included 67 participants and lasted seven weeks; participants took Promacta daily. Between weeks 1 and 6, 62% of participants taking Promacta had increased platelet counts, compared to only 32% of the placebo ground. The second trial involved 92 patients and involved daily administration of Promacta over the course of 13 weeks. Here, 41% of those taking Promacta have increased platelet counts for at least a portion of the 13-week period, compared to 3% of those receiving placebo.

The FDA cautions that Promacta should only be prescribed to patients with ITP who are at risk for the types of internal bleeding described above.