
    study was stopped because of safety concerns.
  
['idiopathic pulmonary fibrosis']
['bg00011', 'placebo']

        Key Inclusion Criteria:

          -  Female subjects must be surgically sterile, postmenopausal (minimum 1 year without
             menses), or agree to use 1 or more forms of highly effective contraception from the
             time of signing of the informed consent form (ICF) until 3 months after the last
             injection of study medication. Male subjects must also agree to use 1 or more forms of
             highly effective contraception for either themselves or their partners from signing of
             ICF until 4 months after last injection of study medication.

          -  IPF diagnosed based on modified ATS/ERS/JRS/ALAT IPF guideline for diagnosis and
             management, within 3 years of Screening.

          -  Combination of high-resolution computed tomography (HRCT) pattern and, if one has been
             obtained, surgical lung biopsy pattern, consistent with diagnosis of IPF.

          -  Carbon monoxide diffusion capacity (DLco) (corrected for hemoglobin): 30% to 79%
             predicted of normal at Screening, with no clinically significant deterioration between
             the Screening Visit and randomization, as determined by the Investigator.

          -  Forced (expiratory) vital capacity (FVC) ≥50% predicted of normal at Screening, with
             no clinically significant deterioration between the Screening Visit and randomization,
             as determined by the Investigator.

          -  If a subject is taking nintedanib or pirfenidone, they must be on a stable dose for at
             least 8 weeks prior to randomization.

        Key Exclusion Criteria:

          -  Unable to perform pulmonary functional tests (PFTs) or undergo HRCT procedure.

          -  Peripheral capillary oxygen saturation (SpO2) <90% at rest (if on oxygen
             supplementation, must be ≤2 L/min at rest).

          -  Airway obstruction (i.e., prebronchodilator FEV1/FVC <0.7) or evidence of a
             bronchodilator response as defined by an absolute increase of ≥12% and an increase of
             ≥200 milliliters (mL) in FEV1 or FVC, or both, after bronchodilator use, compared with
             the values before bronchodilator use at Screening.

          -  End-stage fibrotic disease likely requiring organ transplantation within 12 months, or
             if the subject has initiated active evaluation for organ transplantation.

          -  The extent of emphysema in the lungs exceeds fibrosis, based on central review of HRCT
             scans.

          -  Body weight <60 kg at Screening.

          -  History of or ongoing malignant disease, including solid tumors and hematologic
             malignancies, with the exception of basal cell carcinomas, squamous cell carcinomas,
             and carcinoma in situ of the cervix that have been completely excised and considered
             cured >2 years prior to Screening.

          -  Significant cardiac disease (e.g., New York Heart Association Class 3 or 4; myocardial
             infarction within the past 6 months; unstable angina; coronary angioplasty or coronary
             artery bypass graft within the past 6 months; uncontrolled atrial or ventricular
             cardiac arrhythmias; or pulmonary hypertension requiring pharmacologic treatment).

          -  Clinical diagnosis of any connective tissue disease (including but not limited to
             scleroderma, polymyositis/dermatomyositis, systemic lupus erythematosus, and
             rheumatoid arthritis) or a diagnosis of interstitial pneumonia with autoimmune
             features as determined by the Investigator.

          -  Other disease that may interfere with testing procedures or, in the judgment of the
             Investigator, may interfere with study participation or may put the patient at risk
             when participating in this study.

          -  Other unspecified reasons that, in the opinion of the Investigator or Biogen, make the
             subject unsuitable for enrollment.

        NOTE: Other protocol defined Inclusion/Exclusion criteria may apply.
      