A Study to Explore the Therapeutic Effect of HEC585 on Delaying Forced Vital Capacity (FVC) Decline and Tolerance in Progressive Fibrosing Interstitial Lung Disease (PF-ILD) Patients

This study tests an investigational drug called HEC585 to see whether it can slow the worsening of lung function in patients with progressive fibrosing interstitial lung disease (PF-ILD) — a group of conditions where lung tissue becomes progressively scarred, making breathing increasingly difficult over time. You may be eligible if: - You are 18 years of age or older - You have progressive pulmonary fibrosis (not IPF) confirmed on CT scan - Your lung function has measurably declined in the past 12 months - Your FVC is at least 45% of predicted and your DLCO is between 30% and 80% of predicted - You have been on standard treatment for at least 3 months You may NOT be eligible if: - You have idiopathic pulmonary fibrosis (IPF) — the most common form - You have significant pulmonary arterial hypertension with right heart failure - You are expected to need a lung transplant during the study - Your expected survival is less than 6 months - You have had cancer within the past 5 years - You have significant heart disease, severe liver or kidney impairment, or HIV/hepatitis - You are a heavy smoker (10 or more cigarettes per day in the past 3 months) - You are pregnant or breastfeeding Talk to your doctor to see if this trial is right for you.