People with pulmonary hypertension now have a new treatment option at their disposal. The U.S. Food and Drug Administration has approved the drug Revatio, known by its generic name sildenafil citrate, for pulmonary arterial hypertension, says its manufacturer, Pfizer.
Sildenafil citrate is actually the active ingredient in Viagra—Pfizer's medication that it says is used by 26 million men around the world for erectile dysfunction.
Clinical Development History
"Pfizer undertook a 6-year clinical development program in pulmonary arterial hypertension because patients with this devastating disease needed more medical options, and there was evidence that sildenafil could be an effective treatment," said Joe Feczko, MD, President of Worldwide Development and Vice-President of Global Research and Development at Pfizer, in a statement.
The FDA had granted the medication priority review status, an expedited review process for investigational medications that may address unmet medical needs. According to Pfizer, the government agency's approval hinged on a pivotal randomized, double-blind, controlled clinical study involving 277 patients with pulmonary arterial hypertension. Patients were assigned at random to one of three doses of Revatio three times daily or doses of placebo for the same frequency. Researchers then measured the exercise capability of each patient after 12 weeks of therapy.
Drug Demonstrates Efficacy
At the end of the study, those receiving the doses of Revatio showed highly significant improvements in the distance they were able to walk in 6 minutes compared to those consuming a placebo, Pfizer stated. They also showed improvements in their pulmonary artery blood pressure and other measures of heart function in the study. A 1-year placebo-controlled extension trial was also conducted. At its conclusion, the researchers reported that exercise capacity and walking distance were stable in each of the patients who took part, and 94 percent were still alive.
Since no differences in effectiveness were seen between the three dosage groups in the original trial, the drug will be prescribed at the minimum dose used in the trial—20 mg three times per day, Pfizer reported.
A First
The company says its medication will be the first oral therapy for people with early stages of pulmonary hypertension. It is indicated for the treatment of PH to improve exercise ability. Pfizer says the drug has yet to be evaluated in patients currently taking Tracleer (bosentan), manufactured by Actelion Pharmaceuticals as an oral therapy to improve exercise ability in later-stage pulmonary arterial hypertension.1 However, a preliminary European study examining the effectiveness of Revatio and Tracleer reported that the combination may be safe and effective for people with the illness.2
In studies on Revatio, the most common side effects reported were headache, indigestion, flushing, nosebleed, and insomnia, Pfizer stated.
The company says it expects to make the drug available to patients by mid-July.
1. PH Neighborhood. Tracleer: Endothelin Receptor Antagonist. Available at: http://www.phneighborhood.com/content/treatment_options/
medications_for_ph_1643.aspx. Accessed June 9, 2005.
2. Hoeper MM, Faulenbach C, Golpon H, Winkler J, Welte T, Niedermeyer J. Combination therapy with bosentan and sildenafil idiopathic pulmonary arterial hypertension. Eur Respir J 2004 Dec;24(6):1007-10.
John Martin is a long-time health journalist and an editor for Priority Healthcare. His credits include overseeing health news coverage for the website of Fox Television's The Health Network, and articles for the New York Post and other consumer and trade publications.
