A Study to Find an Efficacious and Safe Dose of CHF10067 (Zampilimab) in Participants With Idiopathic Pulmonary Fibrosis

Inclusion Criteria: * Informed consent: Participant's written informed consent obtained prior to any study-related procedure. * Sex and age: Male or female, of any race and ethnicity, aged ≥40 years with a life expectancy of at least 1 year at screening in the opinion of the Investigator. * Body weight ≥45 kg. * Diagnosis of IPF: Diagnosis as defined by the 2018 and 2022 American Thoracic Society/European Respiratory Society/Japanese Respiratory Society/Latin American Thoracic Society Guidelines for a maximum 8 years before screening. The most recent High-resolution computed tomography (HRCT) ≤6 months prior to screening, reviewed by central reading, should be used to confirm the diagnosis. * Lung function: FVC ≥45% of predicted normal value and a ratio of forced expiratory volume in the first second (FEV1)/FVC ≥0.7 at screening. * Diffusing capacity of the lung for carbon monoxide (DLCO) corrected for haemoglobin ≥25% of predicted normal at screening. * Oxygen saturation measured by pulse oximetry (peripheral capillary oxygen saturation \[SpO2\]) \>90% at rest when the maximum oxygen flow is 4 L/min by standard nasal cannula or the equivalent oxygen delivery via reservoir nasal cannula (≤2 L/min). Exclusion Criteria: * Participant with a documented diagnosis of coeliac disease. * Low respiratory tract infection: Documented low respiratory tract infection in the last 4 weeks prior to screening or documented acute exacerbation of IPF (defined as acute worsening or development of dyspnoea typically \<1 month duration; * Lung cancer: Active diagnosis or history of lung cancer. * Emphysema: HRCT (refer to inclusion criterion \[Diagnosis of IPF\]), reviewed by central reading, shows the presence of emphysema ≥20% or that the extent of emphysema is greater than the extent of fibrosis. * Organ transplantation: End-stage fibrotic disease expected to require organ transplantation within 6 months from screening. * Other medical conditions: Clinically relevant and uncontrolled pulmonary (including any non-IPF pulmonary diagnosis), cardiac, hepatic, gastrointestinal, renal, endocrine, metabolic, neurologic, psychiatric disorders, active or untreated latent tuberculosis/tuberculosis infection that may interfere with the participant's ability to complete this study according to the Investigator's judgement. * Any other comorbid non-IPF pulmonary condition that may impact FVC according to the Investigator's judgement. Emphysema is allowed, unless it meets the above exclusion criterion regarding emphysema. * Participant currently treated, or been treated with cytotoxic and immunosuppressant/modulator drugs within 48 weeks prior to screening. Systemic (IV, intramuscular, or oral) corticosteroids prednisone- equivalent dose of \>10 mg/day used for \>10 days. * Hypersensitivity: Known intolerance and/or hypersensitivity to any of the excipients contained in the formulation or any other substance used in the study. * History of allergic or anaphylactic reaction to human, humanised, chimeric immunoglobulins (Igs), or murine monoclonal antibodies.