A Study Evaluating the Safety and Efficacy of Inhaled AP01 in Participants With Progressive Pulmonary Fibrosis

Inclusion Criteria:

• Participant meets criteria for PPF, as follows:

• In subjects with interstitial lung disease (ILD) of known or unknown etiology otherthan idiopathic pulmonary fibrosis (IPF) who have radiological evidence of pulmonaryfibrosis, 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):

1. Relative decline in FVC ≥10% predicted within the previous 24 months compared toScreening Visit 1

2. Relative decline in FVC ≥5 to <10% predicted within the previous 24 months comparedto Screening Visit 1 with at least 1 of the 2 following criteria:

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

• Radiological (HRCT) evidence of disease progression per a local or centralradiologist, for example:

• Increased extent or severity of traction bronchiectasis andbronchiolectasis

• 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

3. Worsening of respiratory symptoms (Note: Changes attributable to comorbidities e.g.,infection, heart failure must be excluded) AND radiological (HRCT) evidence ofdisease 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.

Exclusion Criteria:

• Current treatment with oral pirfenidone or treatment with oral pirfenidone within 3months prior to Screening.

• Elevated liver enzymes and liver injury at Screening defined as:

1. Alanine aminotransferase (ALT) or aspartate aminotransferase (AST) ˃ 3 timesthe upper limit of normal (ULN)

2. Bilirubin >2.0 x ULN

• Renal disease with a creatinine clearance < 30 mL/min, calculated according to theChronic Kidney Disease Epidemiology Collaboration formula. Retesting is allowedonce.

• Diagnosis of idiopathic pulmonary fibrosis (IPF) based on the ATS diagnosticalgorithm for IPF. UIP that is not idiopathic, for example related to rheumatoidarthritis (RA), familial interstitial lung disease (ILD), or other is notexclusionary.

• Greater extent of emphysema than of fibrotic ILD on HRCT. Note: CT results must beconfirmed through the central over read process.

• Significant clinical worsening of PPF between Screening

• Participants who cannot meet protocol-specified Baseline stability criteria. FVCBaseline stability is defined as the FVC assessments at Visit 3 being within ±12% ofthe mean of the FVC assessments obtained at the 2 preceding visits. At Visit 3, ifthe pre-dose FVC is outside of ±12% range, the participant will not be randomizedand will be considered a screen failure.