• Participant meets criteria for PPF, as follows:

• In subjects with interstitial lung disease (ILD) of known or unknown etiology other than idiopathic pulmonary fibrosis (IPF) who have radiological evidence of pulmonary fibrosis, PPF is defined as:

‣ Physiological evidence of disease progression with at least 1 of the following criteria despite treatment with approved or unapproved medications commonly used in practice (per Investigator):

⁃ Relative decline in FVC ≥10% predicted within the previous 24 months based on documented historical spirometry assessments

⁃ Relative decline in FVC ≥5% to \<10% predicted within the previous 24 months based on documented historical spirometry assessments with at least 1 of the 2 following criteria:

∙ Worsening respiratory symptoms (Note: Changes attributable to comorbidities e.g., infection, heart failure must be excluded) OR

‣ Radiological (HRCT) evidence of disease progression per a local or central radiologist (from historical HRCT taken up to 24 months prior to Screening Visit 1), for example:

⁃ Increased extent or severity of traction bronchiectasis and bronchiolectasis

• New ground-glass opacity with traction bronchiectasis

• New fine reticulation

• Increased extent or increased coarseness of reticular abnormality

• New or increased honeycombing

• Increased lobar volume loss

⁃ Worsening of respiratory symptoms (Note: Changes attributable to comorbidities e.g., infection, heart failure must be excluded) AND radiological (HRCT) evidence of disease progression per a local or central radiologist

∙ Meeting all of the following criteria during the Screening Period:

‣ a. FVC ≥45% of predicted normal at Screening Visit 1, b. Forced expiratory volume at 1 second (FEV1)/FVC ≥0.7 or ≥age-adjusted lower limit of normal at Screening Visit 1, c. Diffusing capacity of lung for carbon monoxide (DLCO) ≥30% of predicted, corrected for hemoglobin at Screening Visit 1, d. Acceptability: Participants can perform acceptable spirometry (i.e., meet American Thoracic Society (ATS)/ European Respiratory Society (ERS) acceptability criteria at both Screening Visits).

‣ • For subjects already on nintedanib (up to 30% of subjects): Must have been on nintedanib for at least 6 months prior to Screening with or without dose adjustments and/or drug interruptions during that period. For subjects who have discontinued nintedanib prior to Screening: Must have been off of nintedanib for a minimum of 12 weeks.