The goal of this clinical trial is to learn if the investigational drug CAL101 can help prevent further decline in lung function in adults with Idiopathic Pulmonary Fibrosis.

Researchers will compare CAL101 with placebo to compare change from baseline in forced vital capacity (FVC).

Participants will be randomly assigned to a study group that will receive an IV infusion of either the study medication or placebo about once a month for 6 months.

This is a randomized, double-blind, placebo-controlled study to evaluate the efficacy and safety of CAL101 in participants with IPF, either as standalone treatment or in addition to currently approved antifibrotic treatments..

The study will consist of a 28-days Screening Period, intravenous (IV) infusions of CAL101 or placebo once every 4 weeks over 24 weeks, and a 16 week Follow-up Period.

Inclusion Criteria:

• ≥ 40 years of age
• Diagnosis of IPF supported by centrally read chest high-resolution computed tomography
• Definite or probable usual interstitial pneumonia (UIP) pattern on chest high-resolution computed tomography (HRCT) performed within 12 months of screening, confirmed by central review (if an evaluable HRCT < 12 months is not available, the baseline HRCT will be used to determine eligibility).
• FVC ≥ 45% of predicted (at Screening).
• Diffusing capacity of the lung for carbon monoxide (DLCO) ≥ 25% predicted.
• Forced expiratory volume in 1 second (FEV1)/FVC ≥ 0.70 at Screening or FEV1/FVC ≥ predicted value minus 0.10 (if predicted value according to the spirometry report at Screening is <0.80).
• Either stable dose with an approved antifibrotic for at least 8 weeks prior to screening or not treated with antifibrotics for at least 8 weeks prior to screening.

Exclusion Criteria:

• In the opinion of the Investigator, other clinically significant lung disease (e.g. asthma, emphysema, chronic obstructive pulmonary disease, cavitary or pleural diseases, clinically significant or treatment-requiring pulmonary hypertension) at screening.
• Interstitial lung disease (ILD) other than IPF (including, but not limited to, connective tissue diseases, vasculitis).
• Acute IPF exacerbation within 16 weeks prior to screening and/or during the screening period (investigator-determined).
• Lower respiratory tract infection requiring antibiotics within 4 weeks prior to screening and/or during the screening period.
• Evidence of impaired kidney function, unstable cardiovascular disease, moderate or severe hepatic impairment or any significant disease or condition other than IPF which may interfere with trial procedures or interpretation of trial results, or cause concern regarding the patient's ability to participate in the trial or any medical condition which could lead to a life expectancy < 12months