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

Adults 40 years of age and older with idiopathic pulmonary fibrosis (IPF) or 18 years and older with progressive pulmonary fibrosis (PPF) can participate in this study. Only people who have a chronic cough can take part. The purpose of this study is to find out how well BI 1839100 helps reduce coughing in people with IPF or PPF. Participants who have IPF are put into 4 groups by chance. Participants in 3 groups get different doses of BI 1839100. Participants in 1 group get placebo. Placebo looks like BI 1839100 but does not contain any medicine. Participants take the treatment for 3 months. After 1 month of treatment, participants who take the highest dose will have coughing measured to find out if the medicine works. If it does not work, the study may be stopped. Participants who have IPF are in the study for slightly longer than 4 months. During this time, they visit the study site 7 times. This study will also measure the effects of BI 1839100 on coughing and lung function in a smaller group of people with PPF. During the study, coughing is measured over 24 hours about once per month using a portable device given to participants to use during the study. Participants fill in questionnaires about their coughing. Doctors also perform breathing tests that measure how well the lungs are working at the site visits. Researchers compare the results between participants who take BI 1839100 and placebo. The doctors also regularly check participants' health and take note of any unwanted effects.