Evaluating the Efficacy and Safety of of HSK44459 in People With Progressive Pulmonary Fibrosis

Inclusion Criteria: 1. Adults aged ≥18 year. 2. Diagnosis of PPF other than IPF prior to screening or during the screening period. 3. Patients must meet either of the following conditions: 1\. not on therapy with nintedanib or pirfenidone for at least 8 weeks prior to screening and during the screening period, and not planning to start or restart antiibrotic therapy. 2.on stable therapy with nintedanib or pirfenidone for at least 12 weeks prior to screening and during the screening period. 4.Percentage Predicted Forced Vital Capacity (ppFVC) ≥45% at screening period. 5.Diffusion capacity of the lung for carbon monoxide (DLCO) (corrected for haemoglobin \[Hb\]) ≥ 25% and \<90% of predicted normal at screening period . Exclusion Criteria: 1. Clinically significant airways obstruction (Forced Expiratory Volume in One Second (FEV1)/Forced Vital Capacity (FVC) \< 0.7) at screening. 2. In the opinion of the Investigator, other clinically significant pulmonary abnormalities. 3. Acute ILD exacerbation within 3 months prior to screening and/or during the screening period. 4. History of malignancy within 5 years prior to screening. 5. History of vasculitis.