After week 72, patients who meet the Progression of Disease (POD) definition, which is a ≥ 10% absolute decrease in percent predicted Forced Vital Capacity or a ≥ 15% absolute decrease in percent predicted carbon monoxide diffusing capacity (DLco), will be eligible to receive permitted idiopathic pulmonary fibrosis therapies in addition to their blinded study drug. Permitted idiopathic pulmonary therapies include corticosteroids, azathioprine, cyclophosphamide and N-acetyl-cysteine (with restrictions).