A Study to Evaluate the Efficacy and Safety of Recombinant Human Pentraxin-2 (rhPTX-2; PRM-151) in Participants With Idiopathic Pulmonary Fibrosis

Inclusion Criteria:

• Documented diagnosis of IPF per the 2018 American Thoracic Society (ATS)/EuropeanRespiratory Society (ERS)/Japanese Respiratory Society (JRS)/Latin American ThoracicSociety (ALAT) Clinical Practice Guideline
• High-resolution computed tomography (HRCT) pattern consistent with the diagnosis ofIPF, confirmed by central review of Chest HRCT and central review of any availablelung biopsy (LB)
• Minimum 6 minute walk distance (6MWD) of 150 meters with maximum use of 6 L/min atsea-level and up-to 8 L/min at altitude of supplemental oxygen while maintainingoxygen saturation of greater than or equal to (>/= )83% during the 6 minute walk test (6MWT) during screening
• FVC >/= 45% predicted during screening as determined by the over-reader
• Forced expiratory volume in 1 second (FEV1)/FVC ratio greater than (>) 0.70 duringscreening determined by the over-reader
• Diffusing capacity for carbon monoxide (DLCO) >/= 30% and less than or equal to (</=) 90% of predicted at screening as determined by the over-reader
• If receiving pirfenidone or nintedanib treatment for IPF, the participant must havebeen on treatment for at least 3 months and a stable dose for at least 4 weeks priorto screening, and during screening
• If not currently receiving nintedanib or pirfenidone treatment (either treatment naïveor having previously taken and discontinued) must have discontinued such treatment >/= 4 weeks prior to screening and during screening
• Anticipated life expectancy of at least 12 months at baseline
• Participant and investigator considered all medicinal treatment options and/orpossibly lung transplantation prior to considering participation in the study.
• For women of childbearing potential (excluding participant enrolling in Japan):agreement to remain abstinent or use contraception
• For men: agreement to remain abstinent or use a condom, and agreement to refrain fromdonating sperm
• Anticipated life expectancy of at least 12 months at baseline, according to theinvestigator's judgment
• For participant enrolled in the extended China enrollment phase: current resident ofmainland China, Hong Kong, or Taiwan, and of Chinese ancestry

Exclusion Criteria:

• Evidence of other known causes of Interstitial Lung Disease (ILD)
• FVC% predicted value showing repeated increase in the 6 months period prior toscreening and including screening value
• Emphysema present on greater than or equal to (>/=) 50% of the HRCT, or the extent ofemphysema is greater than the extent of fibrosis, according to central review of theHRCT
• Receiving nintedanib in combination with pirfenidone
• Received cytotoxic, immunosuppressive, cytokine modulating, or receptor antagonistagents (including but not limited to methotrexate, azathioprine, mycophenolatemofetil, cyclophosphamide, cyclosporine or other steroid sparing agent) within 4 weeksprior to or during screening
• Receiving systemic corticosteroids equivalent to prednisone > 10 mg/day or equivalentwithin 2 weeks prior to or during screening
• Acute respiratory or systemic bacterial, viral, or fungal infection either duringscreening or prior to screening and not successfully resolved 4 weeks prior toscreening visit
• Participants with active or latent tuberculosis (confirmed within the 6 months priorto or during screening, by a positive screening test [interferon gamma release assay])
• Resting oxygen saturation of < 89% using up to 4 L/min of supplemental oxygen at sealevel and up to 6 L/min at altitude (>/= 5000 feet [1524 meters] above sea level)during screening
• Class IV New York Heart Association chronic heart failure
• Historical evidence of left ventricular ejection fraction < 35%
• Presence of pulmonary hypertension that, in the investigator's opinion, wouldsubstantially limit the ability to comply with study requirements or may influence anyof the safety or efficacy assessments included in the study
• Cardiopulmonary rehabilitation program based on exercise training that has beencompleted within 8 weeks prior to screening or planned to start during the participantenrollment in this trial
• History of smoking, alcohol or substance abuse disorder, or a malignancy
• Previous treatment with PRM-151
• Clinically significant abnormality on ECG during screening that, in the opinion of theinvestigator, may pose an additional risk in administering study drug to theparticipant including prolonged corrected QT interval > 450 ms (for men) or > 470 ms (for women) on ECG during screening based on the Fridericia correction formula
• Clinically significant laboratory test abnormalities during screening (hematology,serum chemistry, and urinalysis) that, in the opinion of the investigator, may pose anadditional risk in administering study drug to the participant
• Pregnant or breastfeeding, or become pregnant during the study or within 8 weeks afterthe final dose of PRM-151
• Women of childbearing potential (Only for participants enrolling in Japan)