This study is for people with **idiopathic pulmonary fibrosis (IPF)** or **progressive pulmonary fibrosis (PPF)**. Pulmonary fibrosis is a lung disease that makes it hard to breathe. Participants must have previously completed treatment with a medicine called **nerandomilast** or **BI 1015550**. The study aims to see if long-term use of nerandomilast is safe and if it helps improve lung function or delays worsening symptoms.

Participants will take nerandomilast tablets for up to 1 year and 10 months, and they can continue their regular treatments. They will visit their doctors regularly for health check-ups and lung function tests. Women participating should use effective birth control methods. People with certain health issues, like severe depression or recent cancer, cannot join.

• **Duration:** Up to 1 year and 10 months
• **Visits:** Regular doctor visits for check-ups and tests
• **Eligibility:** Must have completed prior nerandomilast treatment study

Participants should consider the commitment to regular doctor visits and the long duration of the study before joining. The study aims to help understand how well nerandomilast works in the long term.