Impact of the removal of the monthly liver function test requirement for ambrisentan.

Background: The management of patients with pulmonary arterial hypertension (PAH) requires extensive coordination between patients, their support system, third-party payers, and healthcare professionals. For patients with PAH who are receiving endothelin receptor antagonists (ERAs), such cross-stakeholder coordination was needed to ensure compliance with a US Food and Drug Administration (FDA) Risk Evaluation and Mitigation Strategy (REMS) requirement for monthly liver function tests (LFTs). In March 2011, the FDA removed this requirement for ambrisentan (Letairis) in conjunction with a change to the product label.