A Phase 2 Study of LTI-03 in Patients With Idiopathic Pulmonary Fibrosis

Rationale: LTI-03 is an experimental medication breathed into the lungs using an inhaler. It is being studied for the treatment of Idiopathic Pulmonary Fibrosis (IPF). IPF is a progressive, fatal lung disease caused by the death of lung cells involved in oxygen uptake and by progressive fibrosis (scarring) of the lungs. As the disease progresses, patients experience loss of lung function and increased breathing problems. LTI-03 is hypothesized to treat IPF by protecting and restoring the function of the oxygen uptake cells and by controlling lung fibrosis which may result in improving lung scarring. The purpose of this research is to evaluate LTI-03 including: its safety, whether it causes side effects, whether it improves lung scarring, and whether it improves IPF symptoms. LTI-03 will be compared to placebo in patients diagnosed with IPF within the last 5 years. Patients on a stable dose of nintedanib, pirfenidone, or nerandomilast (if available by prescription) may participate. Trial Design: This is a Phase 2, randomized, double-blind, placebo-controlled, multi-center study that includes a 28-day Screening Period, a 24-week Treatment Period, and 4-week Follow-up Period. Study Assessments: Up to 9 visits to the study clinic will be required. Safety and tolerability will be evaluated with the following assessments: physical examination; collection of vital sign data (heart rate, blood pressure, respiratory rate and peripheral oxygen saturation \[SpO2\] via pulse oximetry); heart data collected by 12-lead electrocardiogram; and collection of blood samples for safety laboratory tests. In addition, participants will be asked about any adverse events (side effects) they have experienced between clinic visits, if they have changed any medications, and if they are able to properly use their study drug inhaler. Participants will undergo a lung function test (spirometry) at every visit, which will be used to evaluate both safety and efficacy. Another test measuring the diffusion capacity of the lungs for carbon monoxide (DLCO) will be required at Screening only. Blood samples will also be collected at each visit to measure disease biomarkers. At select visits patients will be asked to complete the Living with Pulmonary Fibrosis questionnaire to evaluate their IPF symptoms. Participants will also undergo a specialized lung scan (HRCT) at Baseline and at the End of Treatment to measure changes in lung fibrosis. Interventions: LTI-03 and placebo are provided in powder-filled capsules that participants will self- administer using an inhaler. Placebo capsules look like LTI-03 capsules but have no active ingredients. Approximately 120 participants will be randomly assigned in a blinded manner to one of study drug treatment groups.

NCT Number	NCT06968845
Lead Sponsor	Rein Therapeutics
Conditions	Idiopathic Pulmonary Fibrosis (IPF)
Enrollment	120 participants
Start Date	2026-02-02
Primary Completion	2027-09-30 (estimated)
Study Completion	2027-12-31 (estimated)
Updated on ClinicalTrials.gov	2026-08-13