A Study of Oral Vismodegib in Combination With Pirfenidone in Participants With Idiopathic Pulmonary Fibrosis

Inclusion Criteria: * Have a diagnosis of IPF 5 years from time of screening, confirmed at baseline * Tolerated dose of pirfenidone 1602-2403 mg once daily (QD) for a minimum of 24 weeks required prior to and during screening * Greater than or equal to (\>=) 50 percent (%) and less than or equal to (\<=) 100% of predicted forced vital capacity (FVC) at screening * Stable baseline lung function as evidenced by a difference of less than (\<) 10% in absolute FVC measurements (in liters) between screening and Day 1/Visit 2 prior to enrollment * \>=30% and \<=90% of predicted diffusion capacity of the lung for carbon monoxide at screening * Agree to use protocol defined methods of contraception * Male participants must agree not to donate semen during the study and for at least 2 months (or as per local requirements) after the last dose of vismodegib * Agree not to donate blood or blood products during the study and for at least 9 months (or as per local requirements) after the last dose of study treatment Exclusion Criteria: * Prior treatment with vismodegib or any Hh-pathway inhibitor * Evidence of other known causes of interstitial lung disease * Hospitalization due to an exacerbation of IPF within 4 weeks prior to or during screening * Lung transplant expected within 6 months of screening * Evidence of clinically significant lung disease other than IPF * Post-bronchodilator forced expiratory volume in 1 second/FVC ratio \<0.7 at screening * Any clinically significant medical disease (other than IPF) that is associated with an expected survival of \<6 months, likely to require a change in therapy during the study * Class IV New York Heart Association chronic heart failure or historical evidence of left ventricular ejection fraction \<35% * Known current malignancy or current evaluation for a potential malignancy * Known immunodeficiency, including, but not limited to, human immunodeficiency virus infection * Evidence of acute or chronic hepatitis or known liver cirrhosis * Creatinine clearance \<=30 milliliter per minute, calculated using the Cockcroft-Gault formula