Rein Therapeutics, Inc.

Limitations on Effectiveness of Controls and Procedures

The term “disclosure controls and procedures”, as defined in Rules 13a-15(e) and 15d-15(e) under the Exchange Act, refers to controls and procedures that are designed to ensure that information required to be disclosed by a company in the reports that it files or submits under the Exchange Act is recorded, processed, summarized and reported, within the time periods specified in the SEC’s rules and forms. Disclosure controls and procedures include, without limitation, controls and procedures designed to ensure that information required to be disclosed by a company in the reports that it files or submits under the Exchange Act is accumulated and communicated to the company’s management, including its principal executive and principal financial officers, or persons performing similar functions, as appropriate to allow timely decisions regarding required disclosure.

In designing and evaluating our disclosure controls and procedures, management recognizes that any controls and procedures, no matter how well designed and operated, can provide only reasonable assurance of achieving the desired control objectives. In addition, the design of disclosure controls and procedures must reflect the fact that there are resource constraints and that management is required to apply judgment in evaluating the benefits of possible controls and procedures relative to their costs.

Evaluation of Disclosure Controls and Procedures

Our management, with the participation of our Chief Executive Officer and our interim Chief Financial Officer, evaluated, as of the end of the period covered by this Annual Report on Form 10-K, the effectiveness of our disclosure controls and procedures (as defined in Rules 13a-15(e) and 15d-15(e) under the Exchange Act). Based on that evaluation, our Chief Executive Officer and our interim Chief Financial Officer concluded that our disclosure controls and procedures were not effective at the reasonable assurance level as of December 31, 2025, because of the identified material weaknesses in our internal control over financial reporting described below.

Management’s Annual Report on Internal Control over Financial Reporting

Our management is responsible for establishing and maintaining adequate internal control over financial reporting. Internal control over financial reporting is defined in Rules 13a-15(f) and 15d-15(f) promulgated under the Exchange Act as a process designed by, or under the supervision of, the company’s principal executive and principal financial officers and effected by the company’s board of directors, management and other personnel, to provide reasonable assurance regarding the reliability of financial reporting and the preparation of financial statements for external purposes in accordance with generally accepted accounting principles and includes those policies and procedures that:

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Pertain to the maintenance of records that in reasonable detail accurately and fairly reflect the transactions and dispositions of the assets of the company;

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Provide reasonable assurance that transactions are recorded as necessary to permit preparation of financial statements in accordance with generally accepted accounting principles, and that receipts and expenditures of the company are being made only in accordance with authorizations of management and directors of the company; and

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Provide reasonable assurance regarding prevention or timely detection of unauthorized acquisition, use or disposition of the company’s assets that could have a material effect on the financial statements.

Because of its inherent limitations, internal control over financial reporting may not prevent or detect misstatements. Therefore, even those systems determined to be effective can provide only reasonable assurance with respect to financial statement preparation and presentation. Projections of any evaluation of effectiveness to future periods are subject to the risk that controls may become inadequate because of changes in conditions, or that the degree of compliance with the policies or procedures may deteriorate.

Management conducted an evaluation of the effectiveness of our internal control over financial reporting based on the Internal Control-Integrated Framework (2013) issued by the Committee of Sponsoring Organizations of the Treadway Commission. Based on this evaluation, management concluded that our internal control over financial reporting was not effective as of December 31, 2025 as a result of the material weaknesses discussed below.

Material Weaknesses

We identified material weaknesses in our internal control over financial reporting. A material weakness is a deficiency, or combination of deficiencies, in internal control over financial reporting such that there is a possibility that a material misstatement of our financial statements will not be prevented or detected on a timely basis. We identified the following material weaknesses in internal control over financial reporting: (i) lack of sufficient accounting and supervisory personnel who have the appropriate level of technical accounting experience and training, and (ii) lack of adequate procedures and controls to ensure that accurate financial statements could have been prepared and reviewed on a timely basis for annual reporting purposes.

Management’s Plan to Remediate the Material Weaknesses

The below are actions that we have taken to date to remediate the above-mentioned material weaknesses:

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Enhanced the execution of our risk assessment activities by evaluating whether the design of our internal controls appropriately addresses changes in the business (including changes to people, processes and systems) that could impact our system of internal controls.

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Completed the integration of the acquired systems from the Lung Acquisition into our financial and accounting systems to allow for systematic segregation of duties, and to enhance the accurate and timely preparation and review of financial statements and supporting schedules.

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Engaged a third-party to assist in assessing the design and implementation of controls and develop remediation plans for identified control gaps related to our timely preparation and review of account reconciliations, financial statements and supporting schedules.

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Reported regularly to the audit committee on the progress and results of the remediation plan, including the identification, status and resolution of internal control deficiencies.

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Continued to reassess staffing and add additional resources, as required, with the requisite technical accounting experience and training, to further allow for segregation of duties and to support our system of internal control.

In addition to implementing and executing the aforementioned activities, the following activities are expected to be completed in fiscal year 2026:

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Implement remediation plans for identified control design and implementation gaps.

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Continue to act upon the enhancements to our internal controls that we implemented in 2025.

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Perform testing of operating effectiveness of identified controls over financial reporting including IT General Controls.

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As needed, we will also supplement our internal resources with additional third-party resources to enhance our corporate oversight and monitoring over process-level controls and structures to ensure that there is appropriate assignment of authority, responsibility, and accountability.

The material weaknesses will not be considered remediated until management completes the design and implementation of the measures described above and the controls operate for a sufficient period of time and management has concluded, through testing, that these controls are effective. Management believes that the remediation measures described above will be implemented in a manner such that the controls can be tested, and the identified material weaknesses can be determined to be remediated, however, no assurance can be made that such remediation will occur or that additional material weaknesses will not be identified.

Changes in Internal Control Over Financial Reporting

In connection with our December 31, 2024 10-K, a material weakness in our internal control over financial reporting was identified relating to segregation of duties within our financial accounting system and lack of reviews of account reconciliation and supporting schedules. Management implemented measures designed to ensure that the control deficiencies related to the material weaknesses were remediated, such that the controls are designed, implemented and operating effectively. The remediation actions included hiring of additional accounting personnel which allowed for proper segregation of duties within the financial accounting system and the implementation of internal controls related to the account reconciliation process. Other than the changes to remediate the material weaknesses and the related ongoing remediation activities described above, no change in our internal control over financial reporting (as defined in Rules 13a-15(f) and 15d-15(f) under the Exchange Act) has occurred during the year ended December 31, 2025 that has materially affected, or is reasonably likely to materially affect, our internal control over financial reporting.