Among the core assets that Gilead (Nasdaq: GILD) acquired from Myogen in 2006 for $2.5B was Letairis® (ambrisentan), for the treatment of pulmonary arterial hypertension (PAH), which was then approved by the FDA in mid 2007. After about a quarter in the market Gilead has initiated a Phase IV, randomized, double-blind, placebo-controlled study evaluating Letairis® [...]