A review of post-marketing data has led FDA to remove the liver damage warning from the prescribing information for Gilead Science’s pulmonary arterial hypertension (PAH) therapy Letairis® (ambrisentan 5 mg and 10 mg tablets). The once-daily drug has been approved in the U.S. since 2007 for helping to improve exercise ability and delay clinical worsening in PAH patients with WHO functional Class II-III symptoms. The label update means patients treated using Letairis will no longer need to undergo monthly liver function tests.
The post-marketing data, collected through the Letairis Education and Access Program, reflected the use of ambrisentan over more than 7,800 patient years. Gilead says the data is consistent with results from the clinical trials used to support the drug’s registration. These 12-week controlled studies found the incidence of liver function abnormalities was 0% for Letrairis-treated patients and 2.3% among placebo-treated individuals.
In its 2009 annual report Gilead suggested 200,000 people worldwide suffer from pulmonary arterial hypertension, and Letairis is used by one-third of patients receiving endothelin-receptor antagonist treatment. The firm reported Letairis sales of $64 million in the fourth quarter of 2010, up 23% on Q4 2009 figures. Sales for the 2010 year were up 31%, at $240.3 million.