Safety, Tolerability, and Efficacy Study of Idiopathic Pulmonary Fibrosis

Major Changes: FGCL-3019-049 Protocol Amendment 3 offers long-term extension of treatment
with FG-3019 to eligible Cohort 1-EX (approximately 14 subjects) and Cohort 2 (approximately
28 subjects) subjects who complete the Week 48-EX and Week 48 assessments described in
Protocol Amendment 2, respectively. A subject is eligible for long-term extension of
treatment if the investigator, after discussion with the Fibrogen Medical Monitor, believes
that the subject would benefit from continued treatment with FG-3019.

Main Inclusion Criteria:

1. Age 35 to 80 years, inclusive.

2. Clinical diagnosis of IPF by high resolution computed tomography (HRCT) scan (and in
some cases by surgical lung biopsy) and reduced lung function (forced vital capacity).

3. History of IPF of 5 years duration or less.

4. Evidence of progression of IPF within the last 3-12 months for Cohort 1, or within the
last 18 months for Cohort 2 before screening.

5. Women of childbearing potential, and men, must be willing to use a medically
acceptable method of contraception during the trial and 3 months after the last dose
of study drug.

Main Exclusion Criteria:

1. Women who are pregnant or nursing.

2. History of any other types of lung or heart disease and any other medical conditions
that, in the opinion of the investigator, would preclude the subject's participation
in the study.

3. Clinically important abnormal laboratory tests.

4. Upper or lower respiratory tract infection of any type within 4 weeks of the first
screening visit.

5. Acute exacerbation of IPF within 3 months of the first screening visit.

6. Use of certain medications within 4 weeks of the first screening visit.

7. Receipt of an investigational drug within 6 weeks of the first screening visit.

8. History of cancer of any type in the 5 years preceding the first screening visit,
excluding non-melanomatous skin cancer, localized bladder cancer, or in situ cervical
cancer.

9. Trauma or surgical procedures requiring hospitalization within 4 weeks of the first
screening visit.

10. Planned elective surgery during the study including 4 weeks following the final dose
of study drug.

11. History of allergic or anaphylactic reaction to human, humanized, chimeric or murine
monoclonal antibodies.

12. Inability to cooperate with study personnel or history of non-compliance to a medical
regimen.

13. Previous treatment with FG-3019.