GKT137831 in IPF Patients With Idiopathic Pulmonary Fibrosis

Inclusion Criteria:

1. Age between 40-85 years old.

2. A diagnosis of IPF that fulfills current American Thoracic Society (ATS) Consensus
Criteria.

3. IPF duration <5 years, based on the date of definitive diagnosis.

4. Ability and willingness to give informed consent and adhere to study requirements.

5. Ratio of forced expiratory volume in 1 second to forced vital capacity (FEV1/FVC) >70%
of predicted values

Exclusion Criteria:

1. Diagnosis of major comorbidities expected to interfere with study participation

2. History of malignancy, excluding basal or squamous cell skin cancer and low-risk
prostate cancer, the latter defined as stage T1 or T2a, with prostate specific antigen
<10 ng/dl. NOX inhibition is not known to promote cancer, and these criteria are
within current guidelines.

3. The occurrence of any acute infection requiring systemic antibiotic therapy within 2
weeks prior to Screening (Visit 1).

4. Treatment for >14 days within the preceding month with >20 mg. prednisone (or
equivalent) or any treatment during the last month with a cellular immunosuppressant
(e.g., cyclophosphamide, methotrexate, calcineurin inhibitors, etc.), given increased
risks of opportunistic infections.

5. Treatment with any investigational agent within 4 weeks of Screening (Visit 1) or 5
half-lives of the investigational medicinal product (whichever is longer).

6. Fertile women who do not agree to contraception or abstinence, or who are breast
feeding. IPF is a disease of older adults, and male predominant, so this will not be a
frequent consideration.

7. Subjects with known hypersensitivity to GKT137831 or its excipients (e.g. capsule
"bulking" agents).

8. A history of bone marrow disorder including aplastic anemia, or marked anemia defined
as hemoglobin < 10.0 g/dL (or 6.2 mmol/L).

9. Severe cardiovascular disease, defined as any of the following within the preceding 12
weeks: acute myocardial infarction or unstable angina, a coronary revascularization
procedure, congestive heart failure (NYHA Class III or IV), or stroke, including a
transient ischemic attack.

10. Evidence of cardiac conducting abnormalities, defined as second or third degree
atrial-ventricular (AV) block not successfully treated with a pacemaker, or a personal
or family history of long QT syndrome (QTc interval >450 msec for males or 470 msec
for females).

11. End-stage renal disease requiring dialysis.

12. Undergoing transplantation evaluation, or listed with the United Network for Organ
Sharing (UNOS) as a lung transplantation candidate at the time of enrollment in this
trial.

13. Liver function tests (transaminases, alkaline phosphatase, direct and total bilirubin)
>3x upper limit of normal values