Study Evaluating INS018_055 Administered Orally to Subjects With Idiopathic Pulmonary Fibrosis

Inclusion Criteria: 1. Male or female patients aged ≥40 years based on the date of the written informed consent form 2. Diagnosis of IPF as defined by American Thoracic Society/European Respiratory Society/Japanese Respiratory Society/Latin American Thoracic Association guidelines 3. In a stable condition and suitable for study participation based on the results of medical history, physical examination, vital signs, 12-lead ECG, and laboratory evaluation 4. Meeting all of the following criteria during the screening period: 1. FVC ≥40% predicted normal 2. DLCO corrected for Hgb ≥25% and \<80% predicted normal 3. Forced Expiratory Volume in the first second/FVC (FEV1/FVC) ratio \>0.7 based on pre-bronchodilator value Exclusion Criteria: 1. Acute IPF exacerbation within 4 months prior to Visit 1 and/or Day 1, as determined by the investigator 2. Patients who are unwilling to refrain from smoking within 3 months prior to screening and until the end of the study 3. Female patients who are pregnant or nursing 4. Abnormal ECG findings