A Study of Lebrikizumab in Participants With Idiopathic Pulmonary Fibrosis (IPF)

Inclusion Criteria:

- Have a diagnosis of IPF within the previous 5 years from time of screening and
confirmed at baseline

- FVC >/=40 percent (%) and
- Stable baseline lung function as evidenced by a difference of less than (<) 10% in FVC
(in liters) measurements between screening and Day 1, Visit 2 prior to randomization

- DLco >/=25% and
- Ability to walk >/=100 meters unassisted in 6 minutes

- Cohort A: No background IPF therapy for >/=4 weeks allowed prior to randomization and
throughout the placebo-controlled study period

- Cohort B: Tolerated dose of pirfenidone >/=4 weeks required prior to randomization and throughout the placebo-controlled study
period

Exclusion Criteria:

- History of severe allergic reaction or anaphylactic reaction to a biologic agent or
known hypersensitivity to any component of the lebrikizumab injection

- Evidence of other known causes of interstitial lung disease

- Lung transplant expected within 12 months of screening

- Evidence of clinically significant lung disease other than IPF

- Post-bronchodilator forced expiratory volume in 1 second (FEV1)/FVC ratio <0.7 at
screening

- Positive bronchodilator response, evidenced by an increase of >/=12% predicted and 200
milliliters increase in FEV1 or FVC

- Class IV New York Heart Association chronic heart failure or historical evidence of
left ventricular ejection fraction <35%

- Hospitalization due to an exacerbation of IPF within 4 weeks prior to or during
screening

- Known current malignancy or current evaluation for potential malignancy

- Listeria monocytogenes infection or active parasitic infection within 6 months prior
to Day 1, Visit 2

- Active tuberculosis requiring treatment within 12 months of screening

- Known immunodeficiency, including but not limited to human immunodeficiency virus
infection

- Past use of any anti-interleukin (IL)-13 or anti-IL-4/IL-13 therapy, including
lebrikizumab

- Evidence of acute or chronic hepatitis or known liver cirrhosis

Exclusions Criteria Limited to Cohort B:

- Known achalasia, esophageal stricture, or esophageal dysfunction sufficient to limit
the ability to swallow oral medication

- Tobacco smoking or use of tobacco-related products within 3 months of screening or
unwillingness to avoid smoking throughout the study period

- Known or suspected peptic ulcer

- Any condition that, as assessed by the investigator, might be significantly
exacerbated by the known side effects associated with pirfenidone

- Creatinine clearance <40 milliliters/minute, calculated using the Cockcroft-Gault
formula

- Use of following therapies within 4 weeks of randomization (Day 1, Visit 2) or during
the study: Strong inhibitors of CYP1A2 (Cytochrome P450 Family 1 Subfamily A Member 2)
(example: fluvoxamine or enoxacin); Moderate inducers of CYP1A2 (limited to tobacco
smoking and tobacco-related products)