Corbus Pharmaceuticals Holdings Inc's experimental drug for cystic fibrosis, a rare lung-scarring disease, could be a real money spinner and pose a challenge to rival Vertex Pharmaceuticals Inc's successful treatment, Kalydeco. REUTERS: Corbus Pharmaceuticals Holdings Inc's experimental drug for cystic fibrosis, a rare lung-scarring disease, could be a real money spinner and pose a challenge to rival Vertex Pharmaceuticals Inc's successful treatment, Kalydeco.