Vertex Pharmaceuticals ($VRTX) asked the FDA to approve broader use of its cystic fibrosis drug Kalydeco. Already marketed for patients with a G551 "gateway" mutation, Kalydeco could be approved to treat patients with at least one non-G551 mutation. It's a very small patient group--just 400 worldwide, Vertex says--but it marks the latest step toward growing Kalydeco's market. Studies in other patient groups are ongoing. Release