Inclusion Criteria:

1. Diagnosed with IPF based on either the 2018 American Thoracic Society (ATS)/ European Respiratory Society (ERS)/ Japanese Respiratory Society (JRS)/ Latin American Thoracic Association (ALAT) International Diagnostic Guidelines or on the 2022 updated guidelines within 7 years prior to the date of informed consent. 2. Chest high-resolution computed tomography scan (HRCT) performed within 12 months prior to providing informed consent meeting requirements for IPF diagnosis based on 2018 or 2022 ATS/ERS/JRS/ALAT guidelines and confirmed by central review. 3. Greater than 40% of predicted forced vital capacity (FVC) and a ratio of forced expiratory volume in 1 second (FEV1)/FVC ≥0.7 measured pre-bronchodilator during screening confirmed by central review. 4. A predicted diffusing capacity of the lungs for carbon monoxide (DLCO) (hemoglobin [Hb] corrected) ≥25% during screening confirmed by central review. 5. Oxygen saturation (SpO2) ≥88% with up to 4L O2/min by pulse oximetry at rest. 6. If currently receiving nintedanib, dose must have been stable for ≥3 months prior to randomization. If participant has previously discontinued nintedanib, there is a 6-week washout period required before screening can begin. 7. Has a life expectancy of at least 12 months.

Exclusion Criteria:

1. Unresolved respiratory tract infection within 4 weeks (including coronavirus disease 2019 [COVID-19] infections) or an acute exacerbation of IPF within 3 months prior to screening. 2. Planned surgery during the study. 3. The investigator judges that there has been sustained improvement in the severity of IPF during the 12 months prior to screening, based on changes in FVC, DLCO, and/or HRCT scans of the chest. 4. History of other types of respiratory diseases including diseases or disorders of the airways, lung parenchyma, pleural space, mediastinum, diaphragm, or chest wall that, in the opinion of the investigator, would impact the primary protocol endpoint or ability to do pulmonary function tests (PFTs), or otherwise preclude participation in the study. 5. Likely to have lung transplantation during the study. Note: Participant may be on a lung transplant list if the investigator anticipates the participant will be able to complete the study prior to transplant. 6. Clinically relevant and uncontrolled cardiac, hepatic, gastrointestinal, renal, endocrine, metabolic, neurologic, or psychiatric disorders that may interfere with the participant's ability to complete this study according to the investigator's judgment, or logistical challenges that, in the opinion of the investigator, preclude adequate participation in the study. 7. History or difficulty of swallowing, malabsorption, or other chronic gastrointestinal disease or conditions that may hamper compliance and/or absorption of the study drug. 8. Receiving steroids (excluding topical steroids) in excess of a mean of 10 mg/day of prednisolone or its equivalent within 2 weeks prior to randomization. 9. Received pirfenidone within 3 months prior to randomization. 10. Smoking or vaping of any kind within 3 months of screening.

Arms

Experimental: TTI-101 400 mg/day

Participants will receive 400 mg/day of TTI-101 twice daily (BID) for 12 weeks.

Experimental: TTI-101 800 mg/day

Participants will receive 800 mg/day of TTI-101 BID for 12 weeks.

Experimental: TTI-101 1200 mg/day

Participants will receive 1200 mg/day of TTI-101 BID for 12 weeks.

Placebo Comparator: Placebo

Participants will receive a matching placebo BID for 12 weeks.

Interventions

Drug: - TTI-101

Orally via a tablet.

Drug: - Placebo

Orally via a tablet.