A Study to Test Whether BI 1839100 Improves Cough in People With Idiopathic Pulmonary Fibrosis or Progressive Pulmonary Fibrosis

Inclusion Criteria

For Idiopathic Pulmonary Fibrosis (IPF) cohort:

• Minimum age: 40 years

• Diagnosis of IPF

• Chronic cough (>8 weeks prior to Visit 1) attributed to IPF and refractory to treatment for known causes (Principal Investigator (PI) assessment)

• Cough Severity visual analogue scale (VAS) ≥30 mm at Visit 1 and Visit 2B

• Forced vital capacity (FVC) ≥45% of predicted normal at Visit 1

• Diffusing capacity of the lungs for carbon monoxide (DLCO) >25% of predicted normal at Visit 1

• Patients may be either:

• On stable therapy with nintedanib or pirfenidone for ≥12 weeks prior to Visit 1 and are planning to stay on this background treatment for the whole trial duration. Combination of nintedanib plus pirfenidone will not be allowed

• Not on therapy with nintedanib or pirfenidone for ≥12 weeks prior to Visit 1 (either antifibrotic (AF)-treatment naïve or previously discontinued) and do not plan to start or re-start AF treatment during the trial. It is not permitted to delay nintedanib or pirfenidone therapy for the purpose of participating in this trial

• Patients aged ≥40 years when signing the informed consent

For Progressive Pulmonary Fibrosis (PPF) cohort:

• Minimum age: 18 years

• Diagnosis of PPF

• Chronic cough (>8 weeks prior to Visit 1) attributed to PPF, refractory to treatment for known causes (PI assessment)

• Cough Severity VAS ≥30 mm at Visit 1 and Visit 2B

• FVC ≥45% of predicted normal at Visit 1

• DLCO ≥25% of predicted normal at Visit 1

• If receiving immunomodulatory therapy for interstitial lung disease (ILD), allowed medications include tacrolimus, mycophenolate mofetil, or azathioprine (stable dose for 12 weeks prior to Visit 1)

• Patients may be either:

• On a stable therapy with nintedanib for ≥12 weeks prior to Visit 1 and are planning to stay on this background treatment for the whole trial duration

• Not on a therapy with nintedanib for ≥12 weeks prior to Visit 1 (either AF-treatment naïve or previously discontinued) and do not plan to start or re-start AF treatment during the trial. It is not permitted to delay nintedanib or pirfenidone therapy for the purpose of participating in this trial

• Patients aged >18 years when signing the informed consent Further inclusion criteria apply.

Exclusion criteria for IPF and PPF cohorts:

• Acute exacerbation of IPF/PPF within 12 weeks prior to Visit 1

• Forced expiratory volume in 1 second (Forced expiratory volume in 1 second (FEV1))/FVC <0.7 at Visit 1

• Known reversible airflow obstruction/response to bronchodilators

• In the opinion of the Investigator, other clinically significant pulmonary abnormalities, including primary bronchitic and bronchiectatic disorder

• Upper or lower respiratory tract infection within 4 weeks prior to Visit 1

• Ongoing chronic pulmonary infection (e.g. mycobacterial or fungal disease)

• Current smokers (tobacco use within the 6 months prior to Visit 1)

• Initiation or change in supplemental oxygen requirement during 4 weeks prior to Visit 1 Further exclusion criteria apply.