Rein Therapeutics recently announced the US FDA has lifted the full clinical hold on the Company’s Phase 2 “RENEW” trial evaluating LTI-03 in patients with idiopathic pulmonary fibrosis (IPF).

The FDA’s decision follows a review of Rein’s submission, which addressed all of the agency’s concerns. In its correspondence, the FDA confirmed that Study LTI-03-2001 may proceed and that any prior Full Clinical Hold concerns have been fully resolved.

Brian Windsor, Ph.D., Chief Executive Officer of Rein Therapeutics, commented, “This is a major milestone for us. The FDA’s decision clears the path for us to resume enrollment and continue advancing LTI-03 through our global Phase 2 program. We’re grateful for the FDA’s collaboration and proud of our team for their hard work and dedication to getting to this point. We believe LTI-03 has the potential to meaningfully shift how IPF is treated by not only slowing fibrosis but also supporting lung repair.”

Rein expects to resume patient recruitment in late 2025 or early 2026 across approximately 20 U.S. clinical sites located in Alabama, California, Colorado, Connecticut, Florida, Indiana, Kansas, Massachusetts, Michigan, Missouri, North Carolina, New York, Ohio, South Carolina, and Texas.

The US enrollment complements Rein’s broader global RENEW study, which includes approximately 30 additional sites in the United Kingdom, Germany, Poland, and Australia. The trial is designed to evaluate the safety, tolerability, and efficacy of LTI-03 in up to 120 patients with IPF.

Key secondary endpoints include changes in lung function (FVC) and imaging-based measures of fibrosis progression. Initial topline data is expected in Q3 2026.

LTI-03 is a first-in-class, inhaled peptide therapy derived from Caveolin-1 biology, a key regulator of fibrotic signaling. The drug is designed to inhibit lung scarring while preserving alveolar progenitor cells that are critical for tissue repair and regeneration.

Early data suggests that LTI-03 may represent a dual-acting approach: slowing fibrosis and promoting lung healing.

IPF is a chronic, progressive lung disease characterized by irreversible scarring that impairs the ability to breathe. Despite current FDA-approved therapies aimed at slowing progression, median survival remains only 3–5 years from diagnosis. By some estimates, the global market for fibrosis treatments is projected to exceed $11 billion by 2031, underscoring the urgent need for new and more effective options.

Rein Therapeutics is a clinical-stage biopharmaceutical company advancing a novel pipeline of first-in-class therapies to address significant unmet medical needs in orphan pulmonary and fibrosis indications. Rein’s lead product candidate, LTI-03, is a novel, synthetic peptide with a dual mechanism targeting alveolar epithelial cell survival as well as inhibition of profibrotic signaling. LTI-03 has received Orphan Drug Designation in the U.S. Rein’s second product candidate, LTI-01, is a proenzyme that has completed Phase 1b and Phase 2a clinical trials for the treatment of loculated pleural effusions. LTI-01 has received Orphan Drug Designation in the U.S. and E.U. and Fast Track Designation in the U.S.