Voyager Therapeutics Reports Fourth Quarter and Full Year 2018 Financial Results and Corporate Highlights Initiated RESTORE-1 Phase 2 trial for VY-AADC for Parkinson's disease Began IND-enabling preclinical studies for A

Voyager Therapeutics Reports Fourth Quarter and Full Year 2018 Financial Results and Corporate Highlights

Initiated RESTORE-1 Phase 2 trial for VY-AADC for Parkinson's disease

Began IND-enabling preclinical studies for ALS-SOD1 and Huntington's disease programs

Recently announced strategic collaborations with funding for certain programs and significant upfront and potential near-term payments while retaining commercial optionality and allowing further investment in fully-retained pipeline

CAMBRIDGE, Mass., February 26, 2019 Voyager Therapeutics, Inc. (NASDAQ: VYGR), a clinical-stage gene therapy company focused on developing life-changing treatments for severe neurological diseases, today reported its fourth quarter and full year 2018 financial results, provided corporate highlights, goals and financial guidance and will host a conference call and webcast today at 4:30 p.m. EST to discuss these results.

Since the beginning of 2018, we advanced our lead and pipeline programs, further developed our vectorized antibody platform, and entered into key enabling collaborations, said Andre Turenne, president and chief executive officer of Voyager Therapeutics. The recently announced strategic collaborations provide us considerable expertise from world-class partners and allow us to maintain commercial flexibility while strengthening our capital resources. As we plan for 2019 and beyond, these developments position the company well to achieve our goal of becoming the leading, fully-integrated gene therapy company focused on severe neurological diseases.

2018 and Recent Corporate Highlights

2018 and Recent Program Highlights

Corporate Goals and 2019 Financial Guidance

Voyager is committed to becoming the leading gene therapy company focused on severe neurological diseases with expertise in discovery, development, manufacturing and commercialization of gene therapy products for people living with these diseases. During 2019, Voyager plans to achieve the following corporate and financial goals towards fulfilling this commitment:

Fourth Quarter and Full Year 2018 Financial Results

For the fourth quarter and full year of 2018, Voyager reported:

A GAAP net loss of $22.5 million, or $0.70 per share, for the fourth quarter ended December 31, 2018, compared to a GAAP net loss of $11.8 million, or $0.40 per share, for the same period in 2017, and a GAAP net loss of $88.3 million, or $2.75 per share, for the full year ended December 31, 2018, compared to a GAAP net loss of $70.7 million, or $2.64 per share, for the same period in 2017.

Collaboration revenues of $2.0 million for the fourth quarter of 2018 compared to collaboration revenues of $6.3 million for the fourth quarter of 2017. Collaboration revenues of $7.6 million for the full year ended December 31, 2018 compared to collaboration revenues of $10.1 million for the full year ended December 31, 2017. Collaboration revenues reflect recognition of payments for research and development services provided by Voyager for various programs under the Sanofi Genzyme and AbbVie collaboration agreements and can vary based on quarterly assessments of efforts under the collaborations. The decrease in collaboration revenues for the fourth quarter and full year 2018 compared to the same periods in 2017 reflect the one-time recognition of amounts allocated to Sanofi Genzyme's rights in the Parkinson's program in the fourth quarter of 2017 and the January 1, 2018 adoption of the new revenue accounting standards which modified the Company's recognition methodology. These decreases were partially offset by revenue related to the research services performed under the collaboration agreement with AbbVie entered into in February 2018.

Research and development (R&D) expenses of $16.9 million for the fourth quarter ended December 31, 2018 compared to $13.3 million for the same period in 2017. R&D expenses of $64.9 million for the year ended December 31, 2018 compared to $62.3 million for the same period in 2017. The increase in R&D expenses related primarily to expenditures associated with the development of Voyager's pipeline including costs related to the RESTORE-1 Phase 2 clinical trial for VY-AADC, and increased personnel and facility costs to support the advancement of the pipeline programs.

General and administrative (G&A) expenses of $8.3 million for the fourth quarter ended December 31, 2018 compared to $5.4 million for the same period in 2017. G&A expenses of $33.8 million for the year ended December 31, 2018 compared to $19.7 million for the

same period in 2017. The increase in G&A expenses was primarily due to increased professional fees including consulting and legal costs in addition to personnel and facility costs to support Voyager's growing business.

Cash, cash equivalents, and marketable debt securities as of December 31, 2018 were $155.8 million.

Conference Call Information

Voyager will host a conference call and webcast today at 4:30 p.m. EST. The live call may be accessed by dialing (877) 851-3834 for domestic callers or +1 (631) 291-4595 for international callers and referencing conference ID number 9672838. A live audio webcast of the conference call will be available online from the Investors & Media section of Voyager's website at www.voyagertherapeutics.com. The webcast will be archived for 30 days.

About Voyager Therapeutics

Voyager Therapeutics is a clinical-stage gene therapy company focused on developing life-changing treatments for severe neurological diseases. Voyager is committed to advancing the field of AAV gene therapy through innovation and investment in vector engineering and optimization, manufacturing and dosing and delivery techniques. Voyager's pipeline focuses on severe neurological diseases in need of effective new therapies, including Parkinson's disease, a monogenic form of ALS called SOD1, Huntington's disease, Friedreich's ataxia, neurodegenerative diseases related to defective or excess aggregation of tau protein in the brain including Alzheimer's disease and other tauopathies, neurodegenerative diseases related to defective or excess aggregation of alpha-synuclein protein in the brain including Parkinson's disease and other synucleinopathies, and severe, chronic pain. Voyager has strategic collaborations with Sanofi Genzyme, AbbVie and Neurocrine Biosciences. Founded by scientific and clinical leaders in the fields of AAV gene therapy, expressed RNA interference and neuroscience, Voyager Therapeutics is headquartered in Cambridge, Massachusetts. For more information on Voyager Therapeutics, please visit the company's website at www.voyagertherapeutics.com or follow @VoyagerTx on Twitter and LinkedIn.

Forward-Looking Statements

This press release contains forward-looking statements for the purposes of the safe harbor provisions under The Private Securities Litigation Reform Act of 1995 and other federal securities laws. The use of words such as may, might, will, would, should, expect, plan, anticipate, believe, estimate, undoubtedly, project, intend, future, potential, or continue, and other similar expressions are intended to identify forward-looking statements. For example, all statements Voyager makes regarding the initiation, timing, progress, activities, goals and reporting of results of its preclinical programs and clinical trials and its research and development programs, the potential benefits and future operation of the collaboration agreements with AbbVie and Neurocrine, including any potential future payments thereunder, its ability to advance its AAV-based gene therapies into, and successfully initiate, enroll and complete, clinical trials, the potential clinical utility of its product candidates, its ability to continue to develop its gene

therapy platform, its ability to develop manufacturing capability for its products and successfully transition its manufacturing process, its ability to perform under existing collaborations with, among others, Sanofi Genzyme, AbbVie and Neurocrine and to add new programs to its pipeline, its expected cash, cash equivalents, and marketable debt securities at the end of a fiscal period, the sufficiency of such cash resources, projections of its operating expenses, its ability to enter into new partnerships or collaborations, and the regulatory pathway of, and the timing or likelihood of its regulatory filings and approvals for, any of its product candidates, are forward looking. All forward-looking statements are based on estimates and assumptions by Voyager's management that, although Voyager believes to be reasonable, are inherently uncertain. All forward-looking statements are subject to risks and uncertainties that may cause actual results to differ materially from those that Voyager expected. Such risks and uncertainties include, among others, those related to the initiation and conduct of preclinical studies and clinical trials; the availability of data from clinical trials; the expectations for regulatory communications, submissions and approvals, including antitrust approvals related to Voyager's collaborations; the continued development of the gene therapy platform; Voyager's scientific approach and general development progress; the sufficiency of cash resources; the possibility of timing of AbbVie's exercise of its development and license options under its collaborations, and the availability or commercial potential of Voyager's product candidates. These statements are also subject to a number of material risks and uncertainties that are described in Voyager's most recent Annual Report on Form 10-K filed with the Securities and Exchange Commission, as updated by its subsequent filings with the Securities and Exchange Commission. Any forward-looking statement speaks only as of the date on which it was made. Voyager undertakes no obligation to publicly update or revise any forward-looking statement, whether as a result of new information, future events or otherwise, except as required by law.

Vice President of Corporate Affairs, Communications and Investor Relations

Selected Financial Information

($-amounts in thousands, except per share data)