Rein Therapeutics Announces New Scientific Publication Demonstrating LTI-03 May Reduce Lung Scarring and Protect Cells Needed for Lung Repair in IPF

Rhea-AI Summary

Rein Therapeutics (NASDAQ: RNTX) reported a new medRxiv preprint (Nov 6, 2025) describing an inhaled, randomized dose‑escalation study of LTI-03 in idiopathic pulmonary fibrosis (IPF) patients.

The authors reported that LTI-03 was generally well tolerated, showed reductions in multiple fibrosis‑associated biomarkers, and appeared to preserve alveolar epithelial type II (AT2) progenitor cells, which are important for lung repair. Investigators said the data indicate lung target engagement and support continued development in the ongoing global Phase 2 RENEW trial.

Positive

• LTI-03 generally well tolerated in dose‑escalation IPF study
• Reductions observed in multiple fibrosis‑associated biomarkers
• Evidence of lung target engagement from patient samples
• Preservation of AT2 progenitor cells linked to lung repair
• Data supports advancement into global Phase 2 RENEW trial

Negative

• Findings are from a preprint and not peer reviewed
• Study reports biomarker signals but no clinical efficacy endpoints

Insights

Clinical translational scientist

Preprint reports inhaled LTI-03 was well tolerated and showed target engagement and preservation of repair cells in IPF patients.

The data describe a randomized, dose‑escalation clinical study in idiopathic pulmonary fibrosis where inhaled LTI-03 produced reductions in multiple fibrosis‑associated biomarkers and evidence the compound reached the lung and engaged intended targets. The report also notes preservation of alveolar epithelial type II (AT2) progenitor cells, a mechanistic signal distinct from therapies that only slow progression.

Risks include early‑stage evidence from a preprint rather than a peer‑reviewed report and limited clinical endpoints reported; safety and biomarker changes do not yet prove clinical benefit. Watch for formal peer review, detailed safety tables, and translational biomarker correlations with clinical outcomes over the coming months, particularly updates from the ongoing Phase 2 RENEW trial and any topline or interim data announcements.

Biotech industry analyst

Clinical translational signals support LTI-03 differentiation; practical impact depends on confirmatory Phase 2 results and peer review.

The release highlights biological activity and tolerability of inhaled LTI-03 in IPF patients, citing reductions in fibrosis‑linked proteins and inflammatory signals and preservation of AT2 cells needed for lung repair. These findings explain why the program is advancing into a global Phase 2 RENEW study and provide early evidence of a differentiated mechanism versus therapies that only slow progression.

Key dependencies include peer review of the preprint, the size and statistical robustness of the dose‑escalation study, and whether biomarker effects translate to functional or clinical endpoints in Phase 2. Monitor the RENEW trial’s prespecified endpoints, safety updates, and any independent replication of AT2 preservation within the next 6–18 months.

New data builds on prior results, highlights LTI-03's differentiated approach, and supports the ongoing global Phase 2 RENEW trial

AUSTIN, Texas, Nov. 06, 2025 (GLOBE NEWSWIRE) -- Rein Therapeutics ("Rein") (NASDAQ: RNTX), a biopharmaceutical company advancing a novel pipeline of first-in-class medicines to address significant unmet medical needs in orphan pulmonary and fibrosis indications, announced that a new preprint has been posted to medRxiv describing clinical and translational findings from an inhaled, dose-escalation study of Rein’s lead drug candidate, LTI-03, in idiopathic pulmonary fibrosis (IPF).

The preprint, titled “Inhaled LTI-03 for Idiopathic Pulmonary Fibrosis: A Randomized Dose Escalation Study,” was authored by an international team of investigators, including Philip L. Molyneaux, MD, Nikhil A. Hirani, MD, Robert J. Kaner, MD, Cory M. Hogaboam, PhD, BreAnne MacKenzie, PhD, Andreas Gunther, MD, and others.

The report describes how inhaled LTI-03 was evaluated in IPF patients to assess safety, pharmacokinetics, and biological activity. According to the authors, LTI-03 was generally well tolerated, and samples collected from treated patients showed reductions in multiple fibrosis-associated biomarkers. These biomarkers include proteins and inflammatory signals linked to disease progression, offering evidence that the drug is reaching the lung and engaging its intended targets.

The investigators also reported that LTI-03 helped preserve alveolar epithelial type II (AT2) progenitor cells, which are essential for lung repair and regeneration. Current IPF therapies primarily focus on slowing progression rather than protecting or restoring these cells.

Brian Windsor, Ph.D., Chief Executive Officer of Rein Therapeutics, commented, “This new data adds to a growing body of evidence supporting LTI-03’s potential as a differentiated therapy for IPF. We’re encouraged to see consistent signals across preclinical and clinical work showing that LTI-03 may not only reduce fibrosis but also help protect the lung cells required for healing. IPF patients urgently need better options, and this work reinforces why we are advancing LTI-03 through our Phase 2 RENEW trial.”

Link to full article:
https://www.medrxiv.org/content/10.1101/2025.10.28.25338981v1

About LTI-03
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.

About Idiopathic Pulmonary Fibrosis (IPF)

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.

About Rein Therapeutics

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.

Forward-Looking Statements

This press release may contain forward-looking statements of Rein Therapeutics, Inc. ("Rein", the "Company", "we", "our" or "us") within the meaning of the Private Securities Litigation Reform Act of 1995, including statements with respect to expectations for the Company’s LTI-03 product candidate. We use words such as "anticipate," "believe," "estimate," "expect," "hope," "intend," "may," "plan," "predict," "project," "target," "potential," "would," "can," "could," "should," "continue," and other words and terms of similar meaning to help identify forward-looking statements, although not all forward-looking statements contain these identifying words. Actual results may differ materially from those indicated by such forward-looking statements as a result of various important factors, including: (i) the risk that the Company may not be able to successfully undertake the planned Phase 2 clinical trials of LTI-03 in the United States, United Kingdom, Germany, Poland, and Australia; (ii) success in early phases of pre-clinical and clinicals trials do not ensure later clinical trials will be successful; (iii) the risk that the Company may not be able to obtain additional working capital with which to initiate and complete planned clinical trials of LTI-03 in the United States, United Kingdom, Germany, Poland, and Australia; and (iv) those other risks disclosed in the "Risk Factors" section of the Company's Annual Report on Form 10-K for the year ended December 31, 2024, which is on file with the United States Securities and Exchange Commission (the "SEC") and in subsequent filings that the Company files with the SEC. These forward-looking statements should not be relied upon as representing the Company's view as of any date after the date of this press release, and we expressly disclaim any obligation to update any forward-looking statements, whether as a result of new information, future events or otherwise, except as required by law.

Rein Investor Relations & Media Contact:

Investor Relations

IR@ReinTx.com 

FAQ

What did Rein Therapeutics announce about LTI-03 on November 6, 2025 (RNTX)?

Rein posted a medRxiv preprint reporting an inhaled dose‑escalation study where LTI-03 was generally well tolerated and showed reductions in fibrosis biomarkers.

How did LTI-03 affect lung cells in the IPF study reported by RNTX?

Investigators reported preservation of alveolar epithelial type II (AT2) progenitor cells, which are important for lung repair.

Does the November 6, 2025 RNTX preprint show clinical benefit for LTI-03?

The report shows biomarker and cellular signals but does not present definitive clinical efficacy endpoints.

Will the LTI-03 data affect Rein Therapeutics’ Phase 2 RENEW trial (RNTX)?

Company commentary and investigators said the results support continued development and the ongoing global Phase 2 RENEW trial.

Where can investors read the full LTI-03 preprint referenced by RNTX?

The full preprint is available on medRxiv at the DOI link provided by the company.