Amendment to Annual Report (Form 10-K/A)

This amended report on Form 10-K/A (the "Amendment") amends the Annual Report on Form 10-K of Adicet Bio, Inc. (the "Company") for the year ended December 31, 2025, initially filed with the Securities and Exchange Commission (the "SEC") on March 12, 2026 (the "Original Filing"), for the purpose of updating the disclosure in Item 9A "Controls and Procedures." The Original Filing inadvertently omitted (a) a statement disclosing the conclusions of the Company's principal executive and principal financial officers regarding the effectiveness of the Company's disclosure controls and procedures as of December 31, 2025 and (b) a statement that the disclosure controls and procedures are designed to provide reasonable assurance of achieving their objectives and the conclusions of the principal executive officer and principal financial officer that the controls and procedures are, in fact, effective at the reasonable assurance level. This Amendment corrects such omission and amends and replaces Item 9A "Controls and Procedures" in its entirety.

PART II

Item 9A. CONTROLS AND PROCEDURES

Evaluation of Disclosure Controls and Procedures

Our management, with the participation of our Chief Executive Officer (CEO) and our Chief Financial Officer (CFO) (our principal executive officer and principal financial officer, respectively), evaluated the effectiveness of our disclosure controls and procedures as of December 31, 2025. The term "disclosure controls and procedures," as defined in Rules 13a-15(e) and 15d-15(e) under the Exchange Act, means controls and other procedures of a company 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, as appropriate to allow timely decisions regarding required disclosure.

Management recognizes that any 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. There are inherent limitations to the effectiveness of any system of disclosure controls and procedures. These limitations include the possibility of human error, the circumvention or overriding of the controls and procedures and reasonable resource constraints. In addition, because we have designed our system of controls based on certain assumptions, which we believe are reasonable, about the likelihood of future events, our system of controls may not achieve its desired purpose under all possible future conditions. Our disclosure controls and procedures are designed to provide reasonable assurance of achieving their objectives. Based on that evaluation, our management, with the participation of our Chief Executive Officer and Chief Financial Officer, have concluded that our disclosure controls and procedures were effective as of December 31, 2025. Accordingly, management believes that the financial statements included in this Annual Report on Form 10-K present fairly in all material respects our financial position, results of operations and cash flows for the period presented.

Management's Annual Report on Internal Control over Financial Reporting

Our management is responsible for establishing and maintaining adequate internal control over our financial reporting (as defined in Rules 13a-15(f) and 15d-15(f) under the Exchange Act). Our internal control over financial reporting is designed to provide reasonable assurances regarding the reliability of financial reporting and the preparation of our consolidated financial statements in accordance with U.S. GAAP, and includes those policies and procedures that:

Because of its inherent limitations, internal control over financial reporting may not prevent or detect misstatements. Also, 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.

Our management, with the participation of our Chief Executive Officer and Chief Financial Officer, assessed our internal control over financial reporting as of December 31, 2025. Management based its assessment on criteria established in Internal Control-Integrated Framework issued by the Committee of Sponsoring Organizations of the Treadway Commission and concluded that our internal control over financial reporting was effective at the reasonable assurance level as of December 31, 2025.

This Annual Report on Form 10-K does not include an attestation report from our registered public accounting firm regarding internal control over financial reporting. As we are a non-accelerated filer, management's report is not subject to attestation by our registered public accounting firm.

We cannot assure you that material weaknesses or significant deficiencies will not occur in the future or that we will be able to remediate such weaknesses or deficiencies in a timely manner, which could impair our ability to accurately and timely report our financial position, results of operations or cash flows. For additional information, see the related risks in the section entitled "Risk Factors" of this Annual Report on Form 10-K.

Changes in Internal Control over Financial Reporting

Other than the remediation plan described in our Annual Report on Form 10-K filed with the SEC on March 6, 2025, no change in our internal control over our financial reporting (as defined in Rules 13a-15(f) and 15d-15(f) under the Exchange Act) 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.

Inherent Limitations on Effectiveness of Internal Controls

An effective internal control system, no matter how well designed, has inherent limitations, including the possibility of human error overriding of controls, and therefore can provide only reasonable assurance with respect to reliable financial reporting. Because of its inherent limitations, our internal control over financial reporting may not prevent or detect all misstatements, including the possibility of human error, the circumvention or overriding of controls, or fraud. Effective internal controls can provide only reasonable assurance with respect to the preparation and fair presentation of the consolidated financial statements.

PART IV

Item 15. Exhibits, Financial Statement Schedules.

The following documents are filed as exhibits to this Amendment:

EXHIBIT INDEX

* Filed herewith.

SIGNATURES

Pursuant to the requirements of Section 13 or 15(d) of the Securities Exchange Act of 1934, the registrant has duly caused this report to be signed on its behalf by the undersigned, thereunto duly authorized.