PAH Patient Outcomes Linked to Exercise Capacity
Patients with higher exercise capacity present a reduced risk of pulmonary arterial hypertension-associated death or hospitalization, according to results of a Phase 3 clinical trial.
The research was published in the journal PLOS One, in a study titled “Association between six-minute walk distance and long-term outcomes in patients with pulmonary arterial hypertension: Data from the randomized SERAPHIN trial.”
Pulmonary arterial hypertension (PAH) is characterized by an increase in resistance of the pulmonary vessels network, especially in the pulmonary artery. The increased pulmonary pressure frequently results in the heart’s right ventricular failure.
Another consequence of PAH is the progressive decline of the functional and exercise capacities of patients.
Different therapies were developed and tested in patients, showing a significant effect on exercise capacity and survival. The effectiveness of these therapies is mainly assessed through the six-minute walk distance (6MWD) test in short-term (three to six months) clinical trials.
The 6MWD test is a simple measure of exercise capacity, easily reproduced and usually performed in conjunction with other clinical, functional and hemodynamic (dynamics of blood flow) tests, when treating patients with PAH. It assesses the distance covered over a time of six minutes.
The SERAPHIN study (NCT00660179) investigated the effect of Opsumit (macitentan), marketed by Actelion, an FDA-approved PAH medication, on morbidity and mortality in patients with symptomatic PAH. The 6MWD was measured at baseline and at six months.
The multicenter study enrolled 742 patients of 12 years and older, with a medical diagnosis of PAH and a baseline 6MWD of 50 meters (about 55 yards) or more. Patients were divided equally into three groups: placebo, Opsumit 3 mg, and Opsumit 10 mg, taken once daily.
Results showed that patients with a 6MWD higher than 400 meters (about 437 yards) at month six showed a reduced risk of PAH-related death or hospitalization, compared to patients with a 6MWD of 400 meters or lower. The risk also was lower for patients with 6MWD higher than 430 meters (470 yards) at the baseline and higher than 455 meters (497 yards) at month six.
In contrast, 6MWD changes at month six were not associated with the risk of PAH-related death or hospitalization.
“In the SERAPHIN study, patients with PAH walking more than 400 [meters] had a lower risk of disease progression, including PAH-related death or hospitalization and all-cause death. Although changes in 6MWD were not associated with long-term outcome in patients with PAH, assessing the absolute 6MWD values remains important in the clinical management of patients with PAH,” the team concluded.