# EDGAR Filing Document

**Accession Number:** 0001420565
**File Stem:** 0001193125-25-235152
**Filing Date:** 2025-10
**Character Count:** 10668
**Document Hash:** 9adf569ef04d42f2628c7cf10792aa6e
**Contains OCR:** False
**Source Format:** 

## Filing Content

## Filing Summary
**0001193125-25-235152.hdr.sgml**: 20251009

**ACCESSION NUMBER**: 0001193125-25-235152

**CONFORMED SUBMISSION TYPE**: 8-K

**PUBLIC DOCUMENT COUNT**: 13

**CONFORMED PERIOD OF REPORT**: 20251009

**ITEM INFORMATION**: Other Events

**ITEM INFORMATION**: Financial Statements and Exhibits

**FILED AS OF DATE**: 20251009

**DATE AS OF CHANGE**: 20251009

**FILER**: 

**COMPANY DATA:**
- **COMPANY CONFORMED NAME:** Rein Therapeutics, Inc.
- **CENTRAL INDEX KEY:** 0001420565
- **STANDARD INDUSTRIAL CLASSIFICATION:** PHARMACEUTICAL PREPARATIONS [2834]
- **ORGANIZATION NAME:** 03 Life Sciences
- **EIN:** 134196017
- **FISCAL YEAR END:** 1231

**FILING VALUES:**
- **FORM TYPE:** 8-K
- **SEC ACT:** 1934 Act
- **SEC FILE NUMBER:** 001-38130
- **FILM NUMBER:** 251383624

**BUSINESS ADDRESS:**
- **STREET 1:** 12407 N. MOPAC EXPY.
- **STREET 2:** SUITE 250 #390
- **CITY:** AUSTIN
- **STATE:** TX
- **ZIP:** 78758
- **BUSINESS PHONE:** 7378021989

**MAIL ADDRESS:**
- **STREET 1:** 12407 N. MOPAC EXPY.
- **STREET 2:** SUITE 250 #390
- **CITY:** AUSTIN
- **STATE:** TX
- **ZIP:** 78758

**FORMER COMPANY:**
- **FORMER CONFORMED NAME:** Aileron Therapeutics, Inc.
- **DATE OF NAME CHANGE:** 20240329

**FORMER COMPANY:**
- **FORMER CONFORMED NAME:** AILERON THERAPEUTICS INC
- **DATE OF NAME CHANGE:** 20071207

?xml version='1.0' encoding='ASCII'? 8-K

### UNITED STATES

### SECURITIES AND EXCHANGE COMMISSION

#### WASHINGTON, DC 20549

### FORM 8-K

#### CURRENT REPORT

#### Pursuant to Section 13 or 15(d)

#### of the Securities Exchange Act of 1934

#### Date of report (Date of earliest event reported): October 9, 2025

## REIN THERAPEUTICS, INC.

#### (Exact Name of Registrant as Specified in Its Charter)

---

| | | |
|:---|:---|:---|
| **Delaware** | **001-38130** | **13-4196017** |
| **(State or Other Jurisdiction<br>of Incorporation)** | **(Commission**<br> **File Number)** | **(I.R.S. Employer<br>Identification Number)** |

---

#### 12407 N. Mopac Expy., Suite 250, #390

#### Austin, Texas 78758

#### (Address of principal executive offices)
(737) 802-1989

#### (Registrant's telephone number, including area code)

#### N/A

#### (Former name or former address, if changed since last report)
Check the appropriate box below if the Form 8-K filing is intended to simultaneously satisfy the filing obligations of the registrant under any of the following provisions.

☐ Written communications pursuant to Rule 425 under the Securities Act (17 CFR 230.425)

☐ Soliciting material pursuant to Rule 14a-12 under the Exchange Act (17 CFR 240.14d-2(b)

☐ Pre-commencement communications pursuant to Rule 14d-2(b) under the Exchange Act (17 CFR 240.14d-2(b)

☐ Pre-commencement communications pursuant to Rule 13e-4(c) under the Exchange Act (17 CFR 240.13e-4(c)

Securities registered pursuant to Section 12(b) of the Act:

---

| | | |
|:---|:---|:---|
| **Title of each class** | **Trading**<br> **Symbol(s)** | **Name of each exchange**<br> **on which registered** |
| Common stock: Par value $.001 | RNTX | Nasdaq Capital Market |

---

Indicate by check mark whether the registrant is an emerging growth company as defined in Rule 405 of the Securities Act of 1933 (§230.405 of this chapter) or Rule 12b-2 of the Securities Exchange Act of 1934 (§240.12b-2 of this chapter).

Emerging growth company ☐

If an emerging growth company, indicate by check mark if the registrant has elected not to use the extended transition period for complying with any new or revised financial accounting standards provided pursuant to Section 13(a) of the Exchange Act. ☐

------

---

| | |
|:---|:---|
| **Item 8.01** | **Other Information.**  |

---

On October 9, 2025, Rein Therapeutics, Inc. (the "Company") issued a press release concerning it receipt of authorization from the European Medicines Agency to initiate the Company's Phase 2 "RENEW" clinical trial, at sites in Germany and Poland, of its lead candidate, LTI-03, for the treatment of idiopathic pulmonary fibrosis. A copy of the press release is attached as Exhibit 99.1 hereto.

---

| | |
|:---|:---|
| **Item 9.01** | **Financial Statements and Exhibits**  |

---

(d) Exhibits

The following exhibits are filed with this report:

---

| | |
|:---|:---|
| Exhibit 99.1 | [The Company's press release dated October 9, 2025](d11439dex991.htm) |
| Exhibit 104 | Cover Page Interactive Data File (embedded within the Inline XBRL document) |

---

------

#### SIGNATURES
Pursuant to the requirements of the Securities Exchange Act of 1934, the registrant has duly caused this report to be signed on its behalf by the undersigned hereunto duly authorized.

---

| | | |
|:---|:---|:---|
| | **REIN THERAPEUTICS, INC.** | **REIN THERAPEUTICS, INC.** |
| Dated: October 9, 2025 |  | */s/ Brian Windsor* |
|  |  | Brian Windsor, Ph.D., |
|  |  | Chief Executive Officer |

---

## Exhibit 99.1

**Exhibit 99.1** 

**Rein Therapeutics Receives European Regulatory Approval to Initiate Phase 2 Trial of** 

**LTI-03 in Idiopathic Pulmonary Fibrosis** 

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;• EMA approval covers study sites in Germany and Poland as part of the Company's global Phase 2 RENEW trial

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;• Trial will evaluate LTI-03, a first-in-class therapy designed to both reduce lung scarring and promote repair

AUSTIN, Texas, Oct. 9, 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 that it has received authorization from the European Medicines Agency (EMA) to initiate the Company's Phase 2 "RENEW" clinical trial of its lead candidate, LTI-03, for the treatment of idiopathic pulmonary fibrosis (IPF).

The approvals cover clinical trial sites in Germany and Poland, which will serve as key European centers for the global study. Rein has already received regulatory clearance from the U.K.'s Medicines and Healthcare products Regulatory Agency (MHRA).

Brian Windsor, Chief Executive Officer of Rein Therapeutics, commented, "These new authorizations mark another important milestone in our global RENEW trial. With approvals now in the U.K., Germany, and Poland, we are well positioned to begin enrolling patients in multiple regions and advance LTI-03 toward our goal of redefining how pulmonary fibrosis is treated. We are grateful to our clinical partners across Europe for their collaboration and commitment to improving outcomes for patients with IPF."

**About the RENEW Trial** 

The RENEW trial is a randomized, double-blind, placebo-controlled Phase 2 study evaluating the safety, tolerability, and efficacy of LTI-03 in patients with IPF. The study will enroll up to 120 patients globally, with a treatment duration of 24 weeks across two dosing groups.

Key secondary endpoints include changes in lung function (FVC) and imaging-based assessments of fibrosis progression.

LTI-03 is a Caveolin-1–derived peptide designed to both inhibit fibrosis and support regeneration of healthy lung tissue by protecting alveolar progenitor cells that are critical for repair.

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**About Idiopathic Pulmonary Fibrosis (IPF)** 

IPF is a chronic, progressive lung disease characterized by irreversible scarring that makes it increasingly difficult for patients to breathe. Median survival is 3–5 years after diagnosis, even with currently approved therapies, which primarily aim to slow disease progression rather than restore lung function.

According to the National Institutes of Health (NIH), IPF has an estimated prevalence of 13 to 20 per 100,000 people worldwide. In just the United States alone, about 100,000 people have IPF, and approximately 30,000 to 40,000 new cases are diagnosed each year.

**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 Germany and Poland, (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 Germany and Poland 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.

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**Rein Investor Relations & Media Contact:** 

Investor Relations

**<u>IR@ReinTx.com</u>**