PRospective phenotypIng and Multi-omic Endotyping of Progressive Pulmonary Fibrosis

Inclusion Criteria:

* Age 18-80 years with a diagnosis of non-IPF fibrosing ILD due to CTD-ILD, fHP, or non-IPF IIP based on central review
* Diagnosis of Fibrotic ILD as determined by site investigator.
* Willingness to comply with study procedures and follow-up.
* Provide written informed consent.

Exclusion Criteria:

* Site diagnosis of fibrosing ILD \>5 years prior to Visit 1 (Screening and Baseline Visit).
* Minimal ILD, defined as reticular opacities and/or ground-glass opacities without architectural distortion (traction bronchiolectasis/bronchiectasis or honeycombing) affecting \< 5% of the lung on centralized evaluation of HRCT at Visit 1 (Screening and Baseline Visit). High quality historical chest HRCT may be used if performed within 90 days prior to Visit 1.
* Extent of emphysema \>15% of total lung volume or greater than extent of fibrosis based on central, qualitative assessment of HRCT at Visit 1. High quality historical chest HRCT may be used if performed within 90 days prior to Visit 1.
* Active malignancy within one year prior to Visit 1 (except for non-melanoma skin cancer requiring local treatment).
* Inability to complete full PFT (spirometry and DLCO) at Visit 1. Historical PFT may be used if performed within 90 days prior to Visit 1.
* Taking nintedanib or nerandomilast at Visit 1.
* Pregnancy at screening or plans to become pregnant during follow-up.
* Participation in an interventional clinical trial for fibrotic ILD at the time of Visit 1, or receipt of an investigational drug within the previous 4 weeks of the enrollment visit (Visit 1) or 5 times the half-life, if longer.