The U.S. Food and Drug Administration approved GlaxoSmithKline’s Promacta (eltrombopag), the first oral thrombopoietin receptor agonist indicated for the treatment of thrombocytopenia in patients with chronic immune thrombocytopenic purpura (ITP).

ITP is an autoimmune disease which results in low blood platelet counts. Because platelets contribute to blood clotting, patients with low counts bleed more easily than others, heal more slowly and bruise more often. About 60,000 U.S. adults have chronic ITP.

The drug was discovered as a result of research collaboration between Glaxo and Ligand Pharmaceuticals Inc. The London-based company said that will launch Promacta next week.

Promacta will compete with Amgen Inc’s Nplate, drug that was granted approval last August. However, financial perspectives are better for Glaxo eltrompopag.

According to Rodman & Renshaw’s Michael King, Amgen’s Nplate sales could reach $ 117 million dollars in 2009. Citigroup analysts estimated that GlaxoSmithKline' s Promacta, if approved, has potential sales for $ 510 million dollars for 2012.

Just as it happened with Nplate, Promacta will only be given when other treatments do not offer clinical results (such as corticosteroids, immunoglobulins or splenectomy)

The drug will be filed in Europe before the end of the year (as Revolade brand).