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
of Incorporation)

(Commission

File Number)

(I.R.S. Employer
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

Symbol(s)

Name of each exchange

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

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.

Dated: October 9, 2025

/s/ Brian Windsor

Brian Windsor, Ph.D.,

Chief Executive Officer

Rein Therapeutics, Inc. 8-K