ProMIS Neurosciences Inc.

Evaluation of Disclosure Controls and Procedures

The Company maintains “disclosure controls and procedures,” as defined in Rule 13a-15(e) and Rule 15d-15(e) under the Exchange Act that are designed to ensure that information required to be disclosed 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 our management, including our principal executive and principal financial officers, as appropriate to allow timely decisions regarding required disclosure. Our management, with the participation of our principal executive officer and principal financial officer, evaluated the effectiveness of our disclosure controls and procedures (as defined in Rules 13a-15(e) and 15d-15(e) under the Exchange Act) as of June 30, 2025.

Based on this evaluation, our principal executive officer and principal financial and accounting officer have concluded that our disclosure controls and procedures were not effective due to a material weakness previously identified in our internal control over financial reporting. This material weakness in the Company’s internal control over financial reporting and the Company’s ongoing remediation efforts are described below.

Material Weakness in Internal Control Over Financial Reporting.

The Company’s management, including our Chief Executive Officer and Chief Financial Officer, identified a material weakness in the Company’s internal control over financial reporting. 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 the Company’s annual or interim financial statements will not be prevented or detected on a timely basis. The Company failed to design sufficient and appropriate review controls over certain of its fair value calculations, including the calculation of the fair value of the July 2024 PIPE Warrant Liability during the three months ended September 30, 2024, which could potentially result in a material misstatement that would not be prevented or detected.

Based on this assessment and the material weakness described above, management concluded that the Company’s internal control over financial reporting was not effective and had not yet been remediated by the end of the period covered by this Quarterly Report on Form

10-Q. However, management believes that the unaudited condensed consolidated financial statements present fairly, in all material respects, our financial position, results of operations and cash flows for the periods presented.

Remediation Measures

To address the material weakness in our internal control over financial reporting, described above, we have put in place a number of measures to remediate the material weakness, including ensuring there are appropriate levels of review in place over the calculation of the fair value of our financial instruments. However, the elements of our remediation plan can only be accomplished over time, and we can offer no assurance that these initiatives will ultimately have the intended effects.

Changes in Internal Control Over Financial Reporting** **

Except for the remediation measures in connection with the material weakness described above, there have been no changes in our internal control over financial reporting, as such term is defined in Rules 13a-15(f) and 15d-15(f) promulgated under the Securities Exchange Act of 1934, as amended, that occurred during the three months ended June 30, 2025 that have materially affected, or are reasonably likely to materially affect, our internal control over financial reporting.