The European Medicines Agency has approved Pfizer’s Revatio (sildenafil citrate) for the treatment of pulmonary artery hypertension, a rare and life threatening disorder.

Revatio, which has the same active ingredient as Pfizer’s erectile dysfunction drug Viagra, was approved in the USA earlier this year [[07/06/05b]].

PAH is a rare, aggressive and life-shortening vascular disease, characterised by dangerously high pressure in the blood vessels that lead from the heart to the lungs, which is thought to affect around 100,000 people worldwide. If left untreated, patients have an average survival time of less than three years from diagnosis.

Revatio is the first oral treatment for PAH to be approved for patients with an early stage of the disease, and will muscle in on a number of other drugs approved to treat PAH in recent years, including Swiss company Actelion Pharmaceuticals' endothelin antagonist Tracleer (bosentan), currently its leading product [[21/10/05i]], and CoTherix’ Ventavis (iloprost).

In the USA, United Therapeutics also sells an injectable PA treatment, Remodulin (treprostinil), and last month said it was planning to develop an inhaled version of the drug in partnership with drug delivery specialist Aradigm Corp.

Meanwhile, Encysive Pharmaceuticals has filed for approval to market another oral treatment for PAH, its endothelin antagonist Thelin (sitaxsentan), in Europe and the USA, while fellow US company Myogen has completed Phase III testing of another drug in this class called ambrisentan.