Ligand Pharmaceuticals Incorporated (NASDAQ:LGND) announced today that the U.S. Food and Drug Administration has extended the priority review period for GlaxoSmithKline’s (GSK) New Drug Application (NDA) for PROMACTA (eltrombopag) for the short-term treatment of chronic idiopathic thrombocytopenic purpura (ITP). The Prescription Drug User Fee action date has been extended to September 19, 2008.

GSK submitted an NDA for PROMACTA in December 2007. In March 2008, the FDA granted the drug Priority Review. In May 2008, orphan drug designation was also granted for this indication. On May 30, 2008, the FDA’s Oncology Drugs Advisory Committee (ODAC) panel unanimously voted (16-0) that eltrombopag demonstrated a favorable risk-benefit profile for the short-term treatment of patients with chronic ITP.

If approved, PROMACTA would be the first oral thrombopoietin receptor agonist therapy for the short-term treatment of previously treated patients with chronic ITP to increase platelet counts and reduce or prevent bleeding. Chronic ITP is a disorder marked by increased platelet destruction and/or inadequate platelet production in the blood, which causes an increased risk of bruising and bleeding. PROMACTA is an investigational, once-daily oral treatment that induces the proliferation and differentiation of cells in the bone marrow to produce platelets.

About Ligand Pharmaceuticals

Ligand discovers and develops new drugs that address critical unmet medical needs of patients in the areas of thrombocytopenia, hepatitis C, cancer, hormone-related diseases, osteoporosis and inflammatory diseases. Ligand's proprietary drug discovery and development programs are based on its leadership position in gene transcription technology, primarily related to intracellular receptors.