This study is for people who already took part in an earlier study where they used an inhaled antifibrotic, a medicine that helps stop the thickening of lung tissue. Participants will continue to use this medicine called **pirfenidone** (AP01), inhaled twice a day with a special device called the **eFlow Nebulizer System**. The study includes a start visit, a treatment period, and a follow-up phone call two weeks after finishing the medicine. Participants will keep a diary to track their doses.

• Participants must have completed a previous study with this medicine and agree to use effective birth control during and after the study.
• If you had a lung disease flare-up needing strong medicine recently, you cannot join.
• No participation in other drug studies within the last 30 days.

Participants should have no allergies to the medicine and must have completed the previous study without stopping the medicine. It's important to follow all instructions and attend all study visits for the study's success. The study duration depends on where you live, and you will be contacted about the end of study phone call.