The trial found patients taking the drug experienced a 17% relative improvement in their ability to force air out of their lungs in one second, a common measure of success in treating lung disease, compared with those on a placebo
Vertex's trial would have been deemed a success if it had delivered just a 4.5% improvement in the lung function test.
Shares of Vertex Pharmaceuticals (NASDAQ:VRTX) are up over 14% today, after it announced positive clinical trial results for its cystic fibrosis fighting drug VX-770.
