An Open Label, In-Clinic Study to Assess Respiratory Function and Safety of Escalating Doses of Nalbuphine Extended-Release Tablets (NAL ER) in Subjects With Idiopathic Pulmonary Fibrosis (IPF)

Inclusion criteria: * Diagnosis of IPF as determined by a pulmonologist based on American Thoracic Society (ATS)/ European Respiratory Society (ERS) / Japanese Respiratory Society (JRS) / Asociación Latinoamericana de Tórax (ALAT) guidelines. * SpO2 ≥ 92%, taken after at least 5 minutes in a sitting position, undisturbed and non-stimulated - Saturation of Hemoglobin with Oxygen as measured by pulse oximetry. * FVC ≥ 40% of Global Lung Function Initiative (GLI) 2012 predicted values- Forced Vital Capacity, as determined by spirometry adhering to ATS/ERS guidelines. Exclusion criteria: * Exac…