Hemab Therapeutics Holdings, Inc.

Evaluation of Disclosure Controls and Procedures

Our management, under the supervision and with the participation of our Chief Executive Officer and Chief Financial Officer (our principal executive officer and principal financial officer, respectively), evaluated the effectiveness of our disclosure controls and procedures as of September 30, 2026. The term “disclosure controls and procedures,” as defined in Rules 13a-15(e) and 15d-15(e) under the Securities Exchange Act of 1934, as amended, or the Exchange Act, means controls and other procedures of an issuer that are designed to ensure that information required to be disclosed by an issuer 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 Securities and Exchange Commission's rules and forms. Disclosure controls and procedures include, without limitation, controls and procedures designed to ensure that information required to be disclosed by an issuer in the reports that it files or submits under the Exchange Act is accumulated and communicated to the issuer’s management, including its principal executive and principal financial officers, or persons performing similar functions, as appropriate to allow timely decisions regarding required disclosure.

Management recognizes that any disclosure controls and procedures, no matter how well designed and operated, can provide only reasonable assurance of achieving their objectives, and management necessarily applies its judgment in evaluating the cost-benefit relationship of possible controls and procedures. Based on the evaluation of our disclosure controls and procedures as of September 30, 2026, our Chief Executive Officer and Chief Financial Officer concluded that, as of such date, our disclosure controls and procedures were not effective at the reasonable assurance level because of the material weaknesses in our internal control over financial reporting described below.

In connection with the audit of our consolidated financial statements for the years ended December 31, 2024 and 2025, we identified material weaknesses in our internal control over financial reporting. As defined in the standards of the Public Company Accounting Oversight Board (United States), a material weakness is a deficiency, or a combination of deficiencies, in internal control over financial reporting, such that there is a reasonable possibility that a material misstatement of our annual or interim financial statements will not be prevented or detected on a timely basis.

The material weaknesses were (1) controls around the financial statement close process were not designed or operating effectively, including as a result of an inappropriate segregation of conflicting duties and insufficient evidence of performance and review of controls, and (2) information system controls around user access, segregation of conflicting duties and change management were not designed or operating effectively.

Remediation Plans

We are committed to remediating the material weaknesses described above. During 2026, with the assistance of a third-party consulting firm, we completed a risk assessment and walkthroughs of our business processes over financial reporting, advanced documentation of the related processes and controls, and designed new and enhanced controls over our financial statement close and reporting process and information technology general controls, including controls over user access and change management. We commenced implementation of these controls during the three months ended September 30, 2026 and expect to commence testing of their operating effectiveness during the fourth quarter of 2026.

The material weaknesses will not be considered remediated until the applicable controls have operated for a sufficient period of time and management has concluded, through testing, that these controls are designed and operating effectively. We cannot assure you that the measures we have taken to date, or any measures we may take in the future, will be sufficient to remediate the material weaknesses or to prevent or avoid potential future material weaknesses. As we continue to evaluate and improve our internal control over financial reporting, we may take additional measures or modify the remediation plan described above. See the section titled “Risk Factors—We have identified material weaknesses in our internal control over financial reporting. If we are unable to remedy our material weaknesses, or if we fail to establish and maintain an effective system of internal control over financial reporting, we may be unable to produce timely and accurate financial statements or prevent fraud, which could adversely impact our business and our stock price.”]

Changes in Internal Control over Financial Reporting

Other than the ongoing remediation efforts described above, including the commencement of implementation of new and enhanced controls during the three months ended September 30, 2026, there were no changes in our internal control over financial reporting (as defined in Rules 13a-15(f) and 15d-15(f) under the Exchange Act) that occurred during the three months ended September 30, 2026 that have materially affected, or are reasonably likely to materially affect, our internal control over financial reporting.