Rein Therapeutics, Inc.

UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

WASHINGTON, DC 20549

FORM 10-Q

(Mark One)

For the quarterly period ended September 30,2025

OR

For the transition period from to

Commission File Number:001-38130

Rein Therapeutics, Inc.

(Exact Name of Registrant as Specified in its Charter)

Registrant’s telephone number, including area code: (737)802-1989

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

Indicate by check mark whether the registrant (1) has filed all reports required to be filed by Section 13 or 15(d) of the Securities Exchange Act of 1934 during the preceding 12 months (or for such shorter period that the registrant was required to file such reports), and (2) has been subject to such filing requirements for the past 90 days. Yes ☒ No ☐

Indicate by check mark whether the registrant has submitted electronically every Interactive Data File required to be submitted pursuant to Rule 405 of Regulation S-T (§ 232.405 of this chapter) during the preceding 12 months (or for such shorter period that the registrant was required to submit such files). Yes ☒ No ☐

Indicate by check mark whether the registrant is a large accelerated filer, an accelerated filer, a non-accelerated filer, smaller reporting company, or an emerging growth company. See the definitions of “large accelerated filer,” “accelerated filer,” “smaller reporting company,” and “emerging growth company” in Rule 12b-2 of the Exchange Act.

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. ☐

Indicate by check mark whether the registrant is a shell company (as defined in Rule 12b-2 of the Exchange Act). Yes ☐ No☒

As of November 10, 2025, the registrant had 26,286,382 shares of common stock, $0.001 par value per share, outstanding.

Table of Contents

CAUTIONARY NOTE REGARDING FORWARD-LOOKING STATEMENTS AND INDUSTRY DATA

This Quarterly Report on Form 10-Q of Rein Therapeutics, Inc. (“Rein,” “we,” “us,” “our,” or the “Company”) contains forward-looking statements that involve substantial risks and uncertainties. All statements, other than statements of historical facts, contained in this Quarterly Report on Form 10-Q, including statements regarding our strategy, future operations, future financial position, future revenue, projected costs, prospects, plans and objectives of management and expected market growth are forward-looking statements. The words “anticipate,” “believe,” “continue,” “could,” “estimate,” “expect,” “intend,” “may,” “plan,” “potential,” “predict,” “project,” “should,” “target,” “would,” and similar expressions are intended to identify forward-looking statements, although not all forward-looking statements contain these identifying words.

These forward-looking statements include, among other things, statements about:

•

our plans to develop and commercialize LTI-03, including the potential benefits thereof;

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our ability to secure sufficient additional capital in the near term or implement other strategies needed to alleviate our current substantial doubt about our ability to continue as a going concern;

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our expectations regarding our ability to fund our operating expenses, our planned activities, and capital expenditure requirements with our cash, cash equivalents and investments

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our Phase 2 clinical trial of LTI-03 and our ability to re-start and complete such clinical trial, subject to obtaining additional funding;

•

our decision to temporarily delay further clinical development of LTI-01 until additional funds are raised;

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our unproven approach to drug research and development in the area of fibrotic diseases, with a focus on Caveolin-1, or Cav1, related peptides, and our ability to develop marketable products;

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our future clinical trials for LTI-03 and LTI-01, whether conducted by us or by any future collaborators, including our ability to enroll patients in our clinical trials, the timing of initiation of these trials and of the anticipated results;

•

the success of our remediation efforts related to the material weaknesses identified in our internal controls over financial reporting;

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the timing of and our ability to obtain and maintain marketing approvals for LTI-03 and LTI-01;

•

the rate and degree of market acceptance and clinical utility of any products for which we receive marketing approval;

•

our commercialization, marketing and manufacturing capabilities and strategy;

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our intellectual property position and strategy, and our ability to obtain, maintain and enforce intellectual property rights for our platform and development candidates;

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our ability to identify additional product candidates with significant commercial potential;

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our plans to enter into collaborations for the development and commercialization of LTI-03, LTI-01 and any additional product candidates;

•

our reliance on third-party manufacturing and supply vendors and contract research organizations, or CROs;

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potential benefits of any future collaboration;

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developments relating to our competitors and our industry;

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the impact of general economic conditions, including inflation and the imposition of new or revised tariffs or other trade restrictions; and

•

the impact of government laws and regulations.

We may not actually achieve the plans, intentions or expectations disclosed in our forward-looking statements, and you should not place undue reliance on our forward-looking statements. Actual results or events could differ materially from the plans, intentions and expectations disclosed in the forward-looking statements we make. We have included important factors in the cautionary statements included in our Annual Report on Form 10-K filed with the SEC on April 7, 2025 (“Annual Report on Form 10-K”) and subsequently filed by reports, particularly in the “Risk Factors” section, which could cause actual results or events to differ materially from the forward-looking statements that we make. Our forward-looking statements do not reflect the potential impact of any future acquisitions, mergers, dispositions, collaborations, joint ventures or investments that we may make or enter into.

You should read this Quarterly Report on Form 10-Q and the documents that we reference herein and have filed or incorporated by reference hereto completely and with the understanding that our actual future results may be materially different from what we expect. We do not assume any obligation to update any forward-looking statements, whether as a result of new information, future events or otherwise, except as required by law.

This Quarterly Report on Form 10-Q includes or incorporates by reference statistical and other industry and market data that we obtained from industry publications and research, surveys and studies conducted by third parties. Industry publications and third-party research, surveys and studies generally indicate that their information has been obtained from sources believed to be reliable, although they do not guarantee the accuracy or completeness of such information.

Effective on January 10, 2025, we amended our Restated Certificate of Incorporation, as amended, to effect a change in our name from “Aileron Therapeutics, Inc.” to “Rein Therapeutics, Inc.” Unless the context otherwise requires, references in this Quarterly Report on Form 10-Q to “we,” “us,” “our” and the “Company” refer to Rein Therapeutics, Inc. and its wholly owned subsidiaries.