Inclusion Criteria:

• Adult male or female patients.
• Documented diagnosis of IPF according to the current American Thoracic Society/European Respiratory Society/Japanese Respiratory Society/ American Latin Thoracic Association (ATS/ERS/JRS/ALAT) guidelines.
• Signed written informed consent.

Exclusion Criteria:

• Age ≤40 years.
• IPF disease diagnosis >5 years.
• Forced vital capacity (FVC) <40% of predicted value.
• Carbon monoxide diffusing lung capacity (DLco) corrected for hemoglobin <30% of predicted value.
• Severe chronic obstructive bronchitis as characterized by forced expiratory volume in 1 second /forced vital capacity (FEV1/FVC) <0.70.
• Need for 24 hrs of oxygen therapy or oxygen saturation <88% after 10 minutes breathing ambient air at rest.
• Known diagnosis of significant respiratory disorders other than IPF.
• Pulmonary artery hypertension requiring a specific treatment.
• Currently listed and/or anticipated to be listed for lung transplantation within the next 6 months (on an active list).
• History of vasculitis or connective tissue disorders.
• Known human immunodeficiency virus (HIV) or chronic viral hepatitis.
• Patients with active tuberculosis or incompletely treated latent tuberculosis infection.
• Use of any cytotoxic/immunosuppressive agent including but not limited to azathioprine, cyclophosphamide, methotrexate, and cyclosporine within 4 weeks prior to screening.
• Use of any cytokine modulators (etanercept, adalimumab, efalizumab, infliximab, golimumab, certolizumab, rituximab) within 12 weeks or 5 half-lives of screening (24 weeks for rituximab and 24 months for alefacept).
• Use of any investigational drug within 1 month of screening, or 5 half-lives, if known ( whichever is longer), or within 12 weeks for stem cell therapy.

The above information is not intended to contain all considerations relevant to a patient's potential participation in a clinical trial.