Rein Therapeutics Announces Publication of New Translational Data in iScience on Company’s Novel Therapy for Idiopathic Pulmonary Fibrosis

Rhea-AI Summary

Rein Therapeutics (NASDAQ: RNTX) has published new data in iScience demonstrating the potential of its lead drug candidate LTI-03 in treating Idiopathic Pulmonary Fibrosis (IPF). The study, conducted on actual lung tissue from IPF patients, showed that LTI-03 effectively reduced multiple scarring pathways and lowered collagen production without causing cell damage, unlike the current FDA-approved treatment nintedanib.

The research supports Rein's ongoing Phase 2 RENEW trial, which will evaluate LTI-03 in up to 120 IPF patients, with initial data expected in 2026. IPF affects approximately 100,000 people in the U.S. and 70,000 in the U.K., with the global treatment market projected to exceed $11 billion by 2031.

Positive

• LTI-03 demonstrated superior safety profile compared to current FDA-approved treatment nintedanib
• Drug showed effectiveness in reducing multiple scarring pathways in actual IPF patient tissue samples
• Company received MHRA approval for Phase 2 RENEW trial
• Large market opportunity with IPF treatment market projected to exceed $11B by 2031

Negative

• Initial Phase 2 trial data not expected until 2026
• Company faces established competition from FDA-approved treatments

Insights

Biotech Research Analyst

Rein's LTI-03 shows promising anti-fibrotic effects in actual IPF patient tissue with potential safety advantages over current treatments.

The publication in iScience represents a significant translational research milestone for Rein Therapeutics' lead candidate LTI-03. The study utilized ex vivo lung slices from IPF patients—an exceptionally relevant disease model that maintains scarring activity post-collection. This approach provides substantially more predictive value than traditional preclinical models.

LTI-03 demonstrated broad-spectrum anti-fibrotic activity by simultaneously targeting multiple fibrotic pathways (TGFβ, VEGF, PDGF, and FGF), reducing collagen production, and dampening inflammatory signals. Most notably, LTI-03 achieved these effects without the cytotoxicity observed with nintedanib, one of only two FDA-approved therapies for IPF.

This differentiated safety profile could represent a meaningful advantage in the IPF treatment landscape, where current therapies offer modest efficacy and challenging side effect profiles. With 100,000 patients in the US alone and median survival of just 3-5 years despite current treatments, IPF represents both a significant unmet medical need and commercial opportunity ($11 billion market by 2031).

The data supports Rein's advancement into the Phase 2 RENEW trial, which recently received regulatory approval from the UK's MHRA. The study will enroll up to 120 patients, with initial data expected in 2026—a critical catalyst for the company. If these translational findings translate to clinical outcomes, LTI-03 could potentially establish a new standard of care in this devastating disease.

Peer-reviewed publication highlights potential breakthrough anti-fibrotic properties of LTI-03 in lung tissue from IPF patients

AUSTIN, Texas, Sept. 17, 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, today announced the publication of novel data on its lead drug candidate, LTI-03, in iScience, a peer-reviewed, open-access journal published by Cell Press.

The paper, titled “LTI-03 peptide demonstrates anti-fibrotic activity in ex vivo lung slices from IPF patients,” reports how LTI-03 was tested directly on lung tissue donated by patients with idiopathic pulmonary fibrosis (IPF) who underwent lung transplant. In this model, LTI-03 showed signs of reducing scarring and protecting lung cells, reinforcing its potential as an important new therapy.

Key Highlights

1. The study used real lung tissue donated by IPF patients. These samples continued to show scarring activity for several days, making them a highly relevant way to test new therapies.
2. LTI-03 reduced multiple scarring pathways (including TGFβ, VEGF, PDGF, and FGF), while also lowering collagen production and inflammatory signals in diseased lung tissue.
3. Unlike nintedanib, the FDA-approved standard-of-care drug, LTI-03 achieved these effects without causing cell damage or death in patient samples, reinforcing the drug’s strong safety profile.
4. The findings add to the growing body of evidence that LTI-03 has the potential to become a meaningful new therapy for IPF.

Brian Windsor, PhD, Chief Executive Officer of Rein Therapeutics, commented, “Using a highly relevant translational model, this peer-reviewed publication provides further validation of LTI-03’s broad anti-fibrotic effects in IPF lung tissue. These data support our ongoing Phase 2 RENEW trial, where we are evaluating LTI-03 in patients living with IPF, a disease with very limited treatment options and high unmet need.”

Urgent Need

IPF is a progressive fibrotic lung disease that affects approximately 100,000 people in the U.S. and more than 70,000 in the U.K. Median survival is just 3–5 years from diagnosis, even with currently approved therapies. The global market for IPF treatments is projected to exceed $11 billion by 2031, underscoring the urgent need for more effective approaches.

Next Steps

Rein recently announced regulatory approval from the U.K.’s MHRA to initiate the Phase 2 RENEW trial of LTI-03. The trial will evaluate safety, tolerability, and changes in lung function in up to 120 patients, with initial data expected in 2026.

The full article can be found here:

https://www.cell.com/iscience/fulltext/S2589-0042(25)01698-0

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. and is in clinical development. 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 as well as the 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 are the key findings of Rein Therapeutics' (RNTX) LTI-03 study for IPF treatment?

The study showed that LTI-03 reduced multiple scarring pathways and lowered collagen production in IPF patient lung tissue, without causing cell damage unlike the current standard treatment nintedanib.

What is the market size for IPF treatments that Rein Therapeutics (RNTX) is targeting?

The global market for IPF treatments is projected to exceed $11 billion by 2031, with approximately 100,000 patients in the U.S. and 70,000 in the U.K.

When will Rein Therapeutics (RNTX) release data from its Phase 2 RENEW trial?

Initial data from the Phase 2 RENEW trial, which will evaluate LTI-03 in up to 120 patients, is expected in 2026.

How does Rein Therapeutics' LTI-03 compare to current IPF treatments?

Unlike nintedanib, the current FDA-approved standard-of-care drug, LTI-03 achieved anti-fibrotic effects without causing cell damage or death in patient samples, suggesting a potentially superior safety profile.

What is the survival rate for IPF patients that Rein Therapeutics is trying to improve?

The median survival for IPF patients is just 3-5 years from diagnosis, even with currently approved therapies, highlighting the urgent need for more effective treatments.