History or evidence of clinically significant disorder, condition or disease that would pose a risk or interfere with the study

Pregnant or lactating

Clinically significant heart, hepatic or renal disease

History of cancer within 5 years of screening

Infection that is not controlled despite antibiotics or other treatment

History of bleeding diathesis within the last 6 months of Day 1

Known history of human immunodeficiency virus, hepatitis B or C

Concern's for subjects compliance

Other conditions that might put the subject at high risk for treatment complications or reduce the chance to obtain data required

Placed on a lung transplant list

Previous participation in an idiopathic pulmonary fibrosis clinical trial other than for simtuzumab

Long-Term Safety Study of GS-6624 in Adults With Idiopathic Pulmonary Fibrosis (IPF)