Homology Medicines Inc

To the stockholders and the Board of Directors of Homology Medicines, Inc.

Opinion on the Financial Statements

We have audited the accompanying consolidated balance sheets of Homology Medicines, Inc. and its subsidiary (the "Company") as of December 31, 2023 and 2022, the related consolidated statements of operations, comprehensive loss, stockholders' equity, and cash flows, for the years then ended, and the related notes (collectively referred to as the "financial statements"). In our opinion, the financial statements present fairly, in all material respects, the financial position of the Company as of December 31, 2023 and 2022, and the results of its operations and its cash flows for the years then ended, in conformity with accounting principles generally accepted in the United States of America.

Going Concern

The accompanying financial statements have been prepared assuming that the Company will continue as a going concern. As discussed in Note 1 to the financial statements, the Company’s recurring losses from operations incurred since inception, the expectation of continuing losses for the foreseeable future, and discontinuation of all clinical trials and research activities, as well as the Company’s workforce reduction plan, raise substantial doubt about its ability to continue as a going concern. Management's plans in regard to these matters are also described in Note 1. The financial statements do not include any adjustments that might result from the outcome of this uncertainty.

Basis for Opinion

These financial statements are the responsibility of the Company's management. Our responsibility is to express an opinion on the Company's financial statements based on our audits. We are a public accounting firm registered with the Public Company Accounting Oversight Board (United States) (PCAOB) and are required to be independent with respect to the Company in accordance with the U.S. federal securities laws and the applicable rules and regulations of the Securities and Exchange Commission and the PCAOB.

We conducted our audits in accordance with the standards of the PCAOB. Those standards require that we plan and perform the audit to obtain reasonable assurance about whether the financial statements are free of material misstatement, whether due to error or fraud. The Company is not required to have, nor were we engaged to perform, an audit of its internal control over financial reporting. As part of our audits, we are required to obtain an understanding of internal control over financial reporting but not for the purpose of expressing an opinion on the effectiveness of the Company’s internal control over financial reporting. Accordingly, we express no such opinion.

Our audits included performing procedures to assess the risks of material misstatement of the financial statements, whether due to error or fraud, and performing procedures that respond to those risks. Such procedures included examining, on a test basis, evidence regarding the amounts and disclosures in the financial statements. Our audits also included evaluating the accounting principles used and significant estimates made by management, as well as evaluating the overall presentation of the financial statements. We believe that our audits provide a reasonable basis for our opinion.

Critical Audit Matter

The critical audit matter communicated below is a matter arising from the current-period audit of the financial statements that was communicated or required to be communicated to the audit committee and that (1) relates to accounts or disclosures that are material to the financial statements and (2) involved our especially challenging, subjective, or complex judgments. The communication of critical audit matters does not alter in any way our opinion on the financial statements, taken as a whole, and we are not, by communicating the critical audit matter below, providing a separate opinion on the critical audit matter or on the accounts or disclosures to which it relates.

Equity method investment — Refer to Notes 1 and 6 to the financial statements

Critical Audit Matter Description

The Company uses the equity method of accounting to account for its investment in Oxford Biomedica (US) LLC, or OXB (US) LLC. The Company's proportionate share of the net income or loss of OXB (US) LLC is included in consolidated net loss within the caption, loss from equity method investment. During the year-ended December 31, 2023, OXB (US) LLC recorded an impairment of certain long-lived assets, resulting in the Company recording an incremental $14.0 million loss from equity method investment and reducing the balance of the equity method investment to $0 as of December 31, 2023, which required significant estimates and assumptions related to future revenue projections and the selection of a revenue multiplier used in the market approach model.

We identified the estimation of future revenue projections and the use of a revenue multiplier associated with the valuation of the related asset group of OXB (US) LLC as a critical audit matter due to the significant judgments required in both the estimation of future revenue and the selection of the revenue multiplier used in the market approach model. This required a high degree of auditor judgment and an increased extent of effort when performing audit procedures to evaluate the reasonableness of the estimates and assumptions related to the forecasts of future revenues and selection of revenue multipliers.

How the Critical Audit Matter Was Addressed in the Audit

Our audit procedures related to the estimates and assumptions utilized in the market approach model used for the impairment analysis included the following, among others:

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We (1) evaluated the reasonableness of the forecasts of future revenues by comparing those estimates to historical results and internal communications to management and the Board of Directors and (2) evaluated the reasonableness of the valuation methodology utilized in the fair value estimate.

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We read the audited financial statements of OXB (US) LLC as of and for the year ended December 31, 2023, audited in accordance with auditing standards generally accepted in the United States of America.

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We considered whether other information obtained during the course of our audit represented contradictory evidence in relation to selection of the revenue multiplier in the valuation model or the estimated revenue projections utilized in the model.

/s/ Deloitte & Touche LLP

Boston, Massachusetts

March 12, 2024

We have served as the Company's auditor since 2017.