ESC: Bosentan (Tracleer) Slows Progression of Pulmonary Arterial Hypertension

VIENNA, Sept. 5 -- For patients in the early stages of pulmonary arterial hypertension, the use of bosentan (Tracleer) appears to slow the progressive worsening of symptoms, researchers said here.

"The results of our trial confirm for the first time that early diagnosis and treatment of pulmonary arterial hypertension have an impact on a relevant endpoint such as clinical worsening, even for those patients who present with mild symptoms," said cardiologist Nazzareno Galie, M.D., of the University of Bologna in Italy.

About 100,000 patients in the U.S. have pulmonary arterial hypertension, which increases right heart pressure, causing dilation and eventually heart failure.

Dr. Galie and colleagues recruited 185 patients, ages 12 and older, into the Endothelin Antagonist Trial in Mildly Symptomatic PAH patients. They assigned 93 to receive bosentan at 62.5 mg twice a day for four weeks and then 125 mg twice a day thereafter in the six-month study. The other 92 patients were given placebo.

To determine worsening of the condition, patients were assessed for the level of pulmonary vascular resistance at the start of the trial and at the end of the study. Among the patients on bosentan, resistance decreased by 33.5% while resistance decreased by 10% among those on placebo.

The difference, representing a treatment effect of 22.6% in favor of bosentan, (P

The researchers also found that patients receiving bosentan improved their walking distance in six minutes by an average of 11 meters, while placebo patients' walking distance decline and average of eight meters (P=.0758).

The time to clinical worsening, a secondary endpoint, defined as death, hospitalization for PAH and symptomatic progression of PAH, was experienced by 3% of bosentan patients and 11% of placebo patients (P=.0114).

In a second study presented here, extension of bosentan into a pediatric population appeared to result in similar pharmacokinetics as with adults, aid Maurice Beghetti, M.D., of the University Hospital in Geneva, Switzerland.

He said the 2 mg/kg and 4 mg/kg dosing of bosentan for children ages two to 11 was well tolerated by the 36 children in the study.

"These studies represent continued progress in an important field," commented Daniel Jones, M.D., dean of the medical school at the University of Mississippi in Jackson, and president of the American Heart Association. The new drugs such as bosentan have dramatically improved outcomes for patients with pulmonary arterial hypertension. It is gratifying to see the extension of the research into patients with early disease and in children."

Dr. Gali disclosed possible financial conflicts of interest with Pfizer, Actelion Pharmaceuticals Ltd, Schering, Encysive, Myogen, and Mondobiotech. Dr. Beghetti disclosed possible financial conflicts of interest with Actelion, INO Therapeutics, Mondobiotech and Schering.

Dr. Jones noted that as required by his position as AHA president, he has no current financial conflicts of interest.