3 month delay for approval of Ligand/GSK's Promacta

The US Food and Drug Administration has extended the priority review period for UK drug major GlaxoSmithKline and the USA-based Ligand Pharmaceuticals' Promacta (eltrombopag) for the short-term treatment of chronic idiopathic thrombocytopenic purpura. The Prescription Drug User Fee action date has now been extended to September 19.

GSK submitted a New Drug Application for Promacta in December 2007. In March 2008, the FDA granted the drug Priority Review and in May, the agent was designated an orphan drug for this indication. On May 30, just days after the committee had said there was not enough evidence for approval, the FDA's Oncology Drugs Advisory Committee panel unanimously voted that eltrombopag demonstrated a favorable risk-benefit profile for the short-term treatment of ITP patients (Marketletter June 9).

Promacta is an investigational, once-daily oral treatment that induces the proliferation and differentiation of cells in the bone marrow to produce platelets. If approved, it 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.