A Study Evaluating the Efficacy and Safety of Vixarelimab in Participants With Idiopathic Pulmonary Fibrosis and in Participants With Systemic Sclerosis-Associated Interstitial Lung Disease

Inclusion Criteria for all Participants: * FVC ≥45% predicted during screening as determined by the over-reader * Forced expiratory volume in 1 second (FEV1)/FVC ratio \>0.70 during screening as determined by the over-reader * DLco ≥30% and ≤90% of predicted during screening (Hgb corrected) as determined by the over-reader * Minimum 6-MWT distance of 150 m with maximum use of 6 liters per minute (L/min) at sea-level and up to 8 L/min at altitude (\> 5000 feet \[1524 m\] above sea level) of supplemental oxygen while maintaining oxygen saturation of \>83% during the 6MWT during screening * Participant and investigator consideration of all medicinal treatment options and/or possibly lung transplantation prior to consideration of participation in the study Inclusion Criteria for Cohort 1: * Age 40-85 years * Documented diagnosis of IPF or IPF (likely) * HRCT pattern consistent with the diagnosis of IPF, confirmed by central review of chest HRCT and central review of any available lung biopsy * For participants receiving pirfenidone or nintedanib treatment for IPF: treatment for ≥3 months with a stable dose for ≥4 weeks prior to screening and during screening, with plans to continue treatment during the study period Inclusion Criteria for Cohort 2: * Age 18-85 years * Diagnosis of SSc as defined using the American College of Rheumatology/European Alliance of Associations for Rheumatology (EULAR) criteria * HRCT demonstrating ≥10% extent of fibrosis, confirmed by central revie…