Ongoing Clinical Trial: Efficacy of Bosentan in Exercise-Induced PAH Secondary to Congenital Heart Disease

Earlier in the week, Pulmonary Hypertension News reported on how the drug Bosentan improved Pulmonary Hypertension Secondary to IPF in an individual case study. In a related story, medical researchers from the Academic Medical Center in Amsterdam, Netherlands, are currently recruiting adult patients (>18) with congenital heart disease for a clinical trial that aims to identify congenital heart disease patients with exercise-induced pulmonary arterial hypertension. Importantly, this study will analyze whether Bosentan is an effective treatment for these patients.

Pulmonary arterial hypertension (PAH) is a life-threatening condition characterized by abnormally high blood pressure in the main artery leading into the lungs, with 20% of cases aggravated by physical exertion. The results of treatment of patients with exercise-induced PAH, caused by systemic sclerosis and primary pulmonary hypertension with Bosentan (an endothelin receptor blocker), seem to indicate that pulmonary arterial endothelial cells play a role in the disease process. Now, this study will test Bosentan in exercise-induced PAH due to congenital heart disease.

Over 26 weeks, the study will analyze changes in pulmonary arterial pressures at peak exercise in 40 patients with exercise-induced pulmonary arterial hypertension before and after treatment with Bosentan, compared to placebo. After randomization, one group (n=20) will receive a 125 mg tablet of Bosentan twice daily for 6 months. The other group (n=20) will receive a placebo. Bosentan has a known potential risk of liver damage, which will be monitored regularly by laboratory testing of liver transaminases.

Besides exercise echocardiography (30 min), cardiovascular exercise testing (30 min), 12 lead electrocardiogram (10 min) and physical examination (15 min), patients will be assessed through a thorough medical history, asked to answer a Quality-of-Life score (15 min) questionnaire, and submit to blood analyses and laboratory tests.

At the end of study, it will be possible to conclude whether Bosentan decreases mean pulmonary arterial pressure at peak exercise in adult congenital heart disease patients with exercise-induced PAH.

To learn more about this study, visit ClinicalTrials.gov.

In other pulmonary hypertension developments, researchers at Central Hospital in Xi’an China are suggesting PH can be better managed with calorie restriction. A recent report published in the Journal of Cardiovascular Pharmacology, titled “Calorie Restriction Attenuates Monocrotaline-induced Pulmonary Arterial Hypertension in Rats,” showed that caloric restriction in rats improved symptoms of PAH in the animals.