Zephyrus I: Evaluation of Efficacy and Safety of Pamrevlumab in Participants With Idiopathic Pulmonary Fibrosis (IPF)

This is a Phase 3, randomized, double-blind, placebo-controlled, multi-center trial to evaluate the efficacy and safety of pamrevlumab in participants with IPF. Participants who are not being treated with approved IPF therapies (that is, nintedanib or pirfenidone) may be eligible for screening. Examples of reasons participants may not be treated with approved IPF therapies include but are not limited to: * Intolerant or not responsive to approved IPF therapies * Ineligible to receive these therapies * Participant voluntarily declines to receive approved IPF therapies after being fully informed of the potential benefits/risks NOTE: No participant should discontinue an approved IPF therapy for the purpose of enrolling in this study. The study consists of the following study periods: * Main (double blind, placebo-controlled) phase: * Screening period: Up to 6 weeks * Treatment period: 48 weeks * Optional, open-label extension (OLE) phase of pamrevlumab: o Access to pamrevlumab will be available until the last participant completes 48 weeks of treatment in the OLE phase, or pamrevlumab is commercially available for the indication of IPF, or the Sponsor decides to end the OLE phase, whichever occurs first. * Follow-up period/final safety assessments: * 28 days after last dose * 60 days after last dose: follow-up phone call, for a final safety assessment During the treatment period, co-administration of an approved IPF therapy (that is, pirfenidone or nintedanib) is acceptable if clinically indicated in the Investigator's opinion, provided that the Investigator assesses the potential risks/benefits of combining approved IPF therapies with blinded study treatment. Participants who discontinue study treatment for any reason should be encouraged to remain in the study and be followed for all study visits and assessments. Participants who complete the Week 48 visit of the main study (regardless of the number of study drug infusions received) will be eligible to participate in the optional OLE phase of the study that offers continuing access to pamrevlumab regardless of randomization assignment in the main study.