First Oral Drug Proven Effective In Multicenter Trial.(bosentan for the treatment of primary pulmonary hypertension)

2001 OCT 25 - (NewsRx.com & NewsRx.net) -- A first-of-its-kind oral drug has been shown to treat primary pulmonary hypertension (PPH) successfully , according to the results of a multicenter trial led by University of California at San Diego School of Medicine pulmonary specialists.

Not only does the drug, bosentan, reverse the deadly consequences of PPH, which affects thousands of people, but also greatly improves patients' quality of life.

The results, published in the October 6, 2001, issue of The Lancet, suggest that bosentan can increase the exercise capacity of people suffering from the debilitating effects of PPH as well as improve their heart function and reduce other symptoms. By the end of the 12-week study period participants on the drug increased their walking distance, in a standard 6-minute walk, by 70 meters while those on the placebo decreased their distance by six meters. Limited activity and heart function are among the major setbacks for people with PPH, estimated to affect one to two patients per million, or 300 new cases per year.

PPH is a progressive narrowing of the small blood vessels in the lungs (the pulmonary arteries), which leads to enlargement and failure of the right ventricle of the heart, said Richard Channick, MD, UCSD associate clinical professor of medicine, and lead author on the study. If left untreated, it usually results in death.

Along with the death sentence, PPH greatly alters patients' lives, according to Channick. Minor activities can leave patients breathless, and the most reliable current treatment for PPH patients requires continuous intravenous drug administration. The survival rate for a PPH patient after diagnosis is about three years.

The causes of PPH are not entirely clear, but it has been linked to the use of the appetite suppressant Fen-Phen. It also appears related to diseases such as liver disease and HIV infection. Doctors also believe the disease may have a genetic basis.

Bosentan works by blocking a naturally occurring protein called endothelin that occurs in higher levels in people with PPH and is harmful to the pulmonary arteries. The damaged, narrowed pulmonary arteries create the blood flow resistance that results in pulmonary hypertension. Bosentan, an orally-activated endothelin receptor antagonist, interferes with the protein and reverses its damaging effects, resulting in lower artery pressure.