Patients with idiopathic pulmonary fibrosis (IPF) who received ambrisentan are more likely to have their disease worsen and to require hospitalization than those who received placebo, new research suggests.

While the cause of IPF is not yet known, but a protein called endothelin-1 causes the blood vessels to contract and induces lung scarring and proliferation associated with the disease. In the current study, investigators sought to determine if ambrisentan, a selective endothelin receptor antagonist, could reduce the rate of IPF progression.

Participants, all of whom had IPF and minimal or no honeycombing, were prescribed ambrisentan 10mg/d or placebo to assess time to disease progression.

After nearly 35 weeks, researchers found that patients treated with ambrisentan actually had shorter time to disease progression and were more likely to require hospitalization. The study was terminated early due to the low likelihood of showing efficacy by the end of the study.