(HealthDay News) – The endothelin A receptor-selective antagonist ambrisentan is not effective for reducing the rate of idiopathic pulmonary fibrosis (IPF) progression, according to a study published in the May 7 issue of the Annals of Internal Medicine.

To examine whether ambrisentan reduces the rate of IPF progression, Ganesh Raghu, MD, from the University of Washington in Seattle, and colleagues randomized patients (aged 40–80 years) with IPF, with minimal or no honeycombing on high-resolution computed tomography scans, to receive ambrisentan (10mg/day) or placebo.

Noting that interim analysis indicated a low likelihood of showing efficacy for the end point by the scheduled end of the study, the researchers terminated the study after enrollment of 492 patients (75% of intended enrollment; mean duration of exposure to study medication, 34.7 weeks). There was a significantly increased likelihood of meeting the prespecified criteria for disease progression among the ambrisentan-treated vs. placebo-treated patients (27.4% vs. 17.2%; hazard ratio, 1.74). The decline in lung function was seen in 16.7% of ambrisentan-treated patients and in 11.7% of placebo-treated patients (P=0.11). Respiratory hospitalizations were significantly higher in the ambrisentan group than the placebo group (13.4% vs. 5.5%, respectively). There was a nonsignificant difference in the number of deaths between the two groups (7.9% of ambrisentan-treated and 3.7% of placebo-treated patients; P=0.1).

“Ambrisentan was not effective in treating IPF and may be associated with an increased risk for disease progression and respiratory hospitalizations,” the authors write.

Several authors disclosed financial ties to pharmaceutical companies, including Gilead Sciences, which funded the study.

Full Text (subscription or payment may be required)