- According to central readings: Diffusion capacity of the lung for carbon monoxide (DLCO) greater than or equal to (>=) 30 percent (%) predicted, Forced vital capacity (FVC) 40% to 85% predicted, and a ratio of FVC % predicted to DLCO % predicted >=1.8 is acceptable if right heart catheterization within 3 months of screening revealed no pulmonary hypertension. If these criteria are met, then High-resolution computed tomography (HRCT) of lungs will be performed, and must show at least 5% fibrosis for subjects to be eligible.