Homology Medicines : Corporate Presentation - January 2023

Corporate Presentation

January 2023

© Copyright 2023 Homology Medicines, Inc. All rights reserved.

Forward-Looking Statements

This presentation contains forward-looking statements within the meaning of the Private Securities Litigation Reform Act of 1995. We intend such forward-looking statements to be covered by the safe harbor provisions for forward-looking statements contained in Section 27A of the Securities Act of 1933, as amended, and Section 21E of the Securities Exchange Act of 1934, as amended. All statements contained in this presentation that do not relate to matters of historical fact should be considered forward-looking statements, including, without limitation, statements regarding: our expectations surrounding the potential, safety, efficacy, and regulatory and clinical progress of our product candidates; the potential of our gene therapy and gene editing platforms, including our GTx- mAb platform; our plans and timing for the release of additional preclinical and clinical data; our plans to progress our pipeline of genetic medicine candidates and the anticipated timing for these milestones; our expectations surrounding our relationship with Oxford Biomedica Solutions; our competitive position, business strategy, prospective products, timing, design, results and likelihood of success of studies and/or clinical trials; our position as a leader in the development of genetic medicines; and our plans to engage in future collaborations and strategic partnerships. The words "believe," "may," "will," "estimate," "potential," "continue," "anticipate," "intend," "expect," "could," "would," "project," "plan," "target," and similar expressions are intended to identify forward-looking statements, though not all forward-looking statements use these words or expressions. These statements are neither promises nor guarantees, but involve known and unknown risks, uncertainties and other important factors that may cause our actual results, performance or achievements to be materially different from any future results, performance or achievements expressed or implied by the forward-looking statements, including, but not limited to, the following: the impact of the COVID-19 pandemic on our business and operations, including our preclinical studies and clinical trials, and on general economic conditions; we have and expect to continue to incur significant losses; our need for additional funding, which may not be available; failure to identify additional product candidates and develop or commercialize marketable products; the early stage of our development efforts; potential unforeseen events during clinical trials could cause delays or other adverse consequences; risks relating to the regulatory approval process; interim, topline and preliminary data may change as more patient data become available, and are subject to audit and verification procedures that could result in material changes in the final data; our product candidates may cause serious adverse side effects; inability to maintain our collaborations, or the failure of these collaborations; our reliance on third parties, including for the manufacture of materials for our research programs, preclinical and clinical studies; failure to obtain U.S. or international marketing approval; ongoing regulatory obligations; effects of significant competition; unfavorable pricing regulations, third-party reimbursement practices or healthcare reform initiatives; product liability lawsuits; securities class action litigation; failure to attract, retain and motivate qualified personnel; the possibility of system failures or security breaches; risks relating to intellectual property; and significant costs incurred as a result of operating as a public company. These and other important factors discussed under the caption "Risk Factors" in our Quarterly Report on Form 10-Q for the quarter ended September 30, 2022 and our other filings with the Securities and Exchange Commission could cause actual results to differ materially from those indicated by the forward-looking statements made in this presentation. Any such forward-looking statements represent management's estimates as of the date of this presentation. While we may elect to update such forward-looking statements at some point in the future, we disclaim any obligation to do so, even if subsequent events cause our views to change.

This presentation also includes statistical and other industry and market data that we obtained from industry publications and research, surveys and studies conducted by third parties or us. Industry publications and third-party research, surveys and studies generally indicate that their information has been obtained from sources believed to be reliable, although they do not guarantee the accuracy or completeness of such information. All of the market data used in this presentation involves a number of assumptions and limitations, and you are cautioned not to give undue weight to such estimates. While we believe these industry publications and third-party research, surveys and studies are reliable, we have not independently verified such data. The industry in which we operate is subject to a high degree of uncertainty, change and risk due to a variety of factors, which could cause results to differ materially from those expressed in the estimates made by the independent parties and by us.

2 | © Copyright 2023 Homology Medicines, Inc. All rights reserved.

Homology is a Leader in Genetic Medicines, Developing One-Time, Potentially Life-Changing Therapies for Patients, Caregivers and Families

By leveraging Homology's AAV technology, including our exclusive

AAVHSC platform, we aim to:

Deliver best-in-class
gene editing therapies		Advance gene therapy		Replace chronic		Pursue strategic
by utilizing		with targeted capsid		therapies with one-		partnerships to
homologous		selection coupled with		time GTx-mAb		progress and expand
recombination-based		optimized design		treatments		the platform
integration

3 | © Copyright 2023 Homology Medicines, Inc. All rights reserved.

Fully Integrated Gene Therapy and Gene Editing Company With Clinical Programs

Research and Development	Technology	Rare Disease Experience
Phase 1 gene editing in PKU	15 novel AAVHSCs; potential to expand	Team's prior experience includes
Phase 1 gene therapy in Hunter syndrome	Equity investments from Pfizer and Novartis	developing and/or launching
11 rare disease drugs with
Phase 1/2 gene therapy in PKU	Extensive I.P. portfolio
>$2B in annual revenue

Discovery, Research	AAV Process Development
& Development	and Manufacturing Expertise
5 development candidates	Co-owned Manufacturing and Innovation
	Business, Oxford Biomedica Solutions

4 | © Copyright 2023 Homology Medicines, Inc. All rights reserved.

Flexible AAVHSC Platform Designed to Address Rare Genetic Disorders and Diseases With Larger Patient Populations

Gene Therapy (Adds a Gene)

Gene Therapy (GTx-mAb)

Gene Editing (Nuclease-Free)

Promoter				Corrective Gene	Promoter-Driven

Enters the Cell's Nucleus

Episome with

Promoter &

Corrective Gene

Mutated Gene	mRNA

Mutated

Protein

Tx-mAb

Enters the Cell's Nucleus

Episome with

Promoter +

Tx-mAb

DNA

mRNA

Tx-mAb

Continuous +

Sustained

Systematic

mAb Levels

Homology Arm

mRNA

Homology Arm

Corrective Gene

Enters the Cell's Nucleus

Mutated

Gene

Homologous

Recombination

Functional

Gene

Protein

5 | © Copyright 2023 Homology Medicines, Inc. All rights reserved.