New Therapy for Pulmonary Arterial Hypertension

In clinical trials, a new oral therapy for pulmonary arterial hypertension (PAH) has demonstrated statistically significant patient improvement in exercise capacity and delay in the time to clinical worsening, compared to placebo. The Cardiovascular and Renal Drugs Advisory Committee of the U.S. Food and Drug Administration (FDA) has voted unanimously to recommend that the FDA approve the drug for the treatment of PAH.

The new drug, bosentan (Tracleer), is a dual endothelin receptor antagonist. European, Australian, and U.S. regulatory authorities have granted bosentan Orphan Drug status for PAH. In clinical trials, the drug produced a 44-meter improvement in walking distance, as measured by a six-minute walk test, compared to placebo. The drug also significantly improved functional status and the time to clinical worsening--defined as death, hospitalization, or the need for intravenous therapy.

PAH is a life-threatening chronic condition that begins as shortness of breath, fatigue, and a reduction in exercise capability. Secondary forms of the disease are related to conditions or tissue disorders that affect the lungs, such as scleroderma, lupus, and AIDS. In untreated patients, the survival rate two years after the onset of symptoms is only 40-55%. Advanced stages require intravenous prostacyclin therapy via a line implanted directly into the heart or, for some, lung transplantation.

Bosentan was developed by Actelion Ltd. (Allschwil, Switzerland), a biopharmaceutical company with a research focus on the endothelium. "We are nearing a milestone in the treatment of pulmonary arterial hypertension,” said principal investigator Lewis Rubin, M.D., professor of medicine, University of California, San Diego (USA). "For the first time, patients and their families can have realistic hope that an oral treatment demonstrating very promising results may soon be made available.”




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