Homology Medicines, Inc., a newly formed genetic medicines company translating proprietary, next generation gene editing and gene therapy technologies into novel treatments for patients with rare diseases, today announced the closing of a $43.5 million Series A preferred stock financing co-led by 5AM Ventures and ARCH Venture Partners. Additional investors included Temasek, Deerfield Management, and ARCH Overage Fund. In conjunction with the financing, Homology hired biotechnology industry veterans who have a demonstrated track record in identifying and developing novel gene therapy and editing technologies, including Arthur Tzianabos, Ph.D., as Chief Executive Officer, Sam Rasty, Ph.D., as Chief Operating Officer, and Albert Seymour, Ph.D. as Chief Scientific Officer. The Company also appointed an experienced Board of Directors and members of the Scientific Advisory Board.

'It is rare to find cutting-edge science that takes a fundamentally new approach placed in the hands of experts who have worked together as a team before to translate new technologies into treatments targeting the underlying cause of serious genetic diseases,' said Dr. Tzianabos. 'We are convinced that this single technology platform, which enables in vivo editing by efficient gene transfer, has broad, unmatched capabilities. With the strong support of our investors and advisors, we will rapidly advance novel treatments that have the potential to cure patients.'

Homology Medicines was founded and incubated with a seed investment within the 4:59 Initiative, the company creation engine of 5AM Ventures. Homology is based on groundbreaking science that harnesses the naturally occurring process of homologous recombination. This non-nuclease-based approach offers clear advantages in its precision, efficiency and on-target in vivo editing of genetic mutations. Homology obtained an exclusive worldwide license to this technology platform, which is based on the pioneering research of Saswati Chatterjee, Ph.D., Department of Surgery, member of the Beckman Research Institute at the City of Hope in California and co-founder and Chair of Homology's Scientific Advisory Board. Dr. Chatterjee is also a member of the Recombinant DNA Advisory Committee (RAC) to the Office of the Director, National Institutes of Health (NIH) and former charter member of the Therapeutic Approaches to Genetic Diseases Study Section of the NIH. Dr. Chatterjee and her team led the first adeno-associated virus (AAV) vector-mediated gene transfer studies into human hematopoietic stem cells and subsequently identified and isolated a series of naturally-occurring AAVs from human CD34+ cells.

'Homology's ability to attract top management, who over many years have gained scientific and practical knowledge of the complexities of developing treatments for rare genetic diseases, is a testament to the strength of our technology platform,' said Kush Parmar, M.D., Ph.D., Managing Partner at 5AM Ventures and Homology Board member. 'The Company has an aggressive development plan and a significant opportunity to leapfrog current strategies in gene therapy and editing as it builds an expansive and high-value clinical pipeline.'

Commenting on the launch of Homology Medicines, Steven Gillis, Ph.D., Managing Director with ARCH Venture Partners and Homology Board member, noted, 'As a scientist and investor, I have evaluated many breakthrough technologies in this field and I believe Homology's technology platform is unique in its ability to leverage naturally occurring genetic mechanisms to both treat and correct diseases in vivo. I look forward to helping Homology lead the next generation gene editing technology that could result in new curative medicines for life-threatening diseases.'

Management Team and Advisors

Arthur Tzianabos, Ph.D., Chief Executive Officer and Director, has led teams in the discovery, development, clinical translation and commercialization of new treatments for serious diseases for over 25 years. He spent nine years at Shire, where he played an active role in the development, approval, and commercial launch of multiple therapies for patients with rare genetic disorders, and worked closely with Business Development and Corporate Venture teams to invest in and acquire new companies and technologies. Earlier in his career, Dr. Tzianabos was an Associate Professor of Medicine at Harvard Medical School and during his 15-year tenure maintained laboratories at Brigham and Women's Hospital and the Department of Microbiology and Molecular Genetics at Harvard Medical School.

Sam Rasty, Ph.D., Chief Operating Officer, was Vice President and Head of New Products at the Rare Diseases Business Unit of Shire. At Shire, he played a pivotal role at the intersection of Commercial, Research and Development and Business Development, driving the strategy for growth of the rare disease business through internal product development, licensing and merger and acquisition activities. His career spans more than 20 years of scientific, clinical, commercial and business development experience in the life sciences across multiple specialty therapeutic areas, rare diseases and technology platforms. Prior to joining Shire, Dr. Rasty was responsible for Corporate Development and Strategic Marketing at Endo Pharmaceuticals, and Global Commercial Strategy and Portfolio Management at GlaxoSmithKline within the global research and development organization.

Albert Seymour, Ph.D., Chief Scientific Officer, was the former Senior Vice President and Global Head of Research and Nonclinical Development at Shire. In this role he led the progression of multiple rare disease programs from Discovery into Development, and through internal research efforts and external partnerships he doubled the rare disease discovery portfolio in less than three years. Dr. Seymour brings more than 20 years of experience bridging Human Genetics with Pharmaceutical R&D, which resulted in the delivery of multiple therapeutic programs into development. This included 14 years spent at Pfizer leading a team in the application of human genetics and computational biology to discover and develop therapeutics and pharmacogenomics strategies.

In addition to Dr. Tzianabos, the Homology Board of Directors consists of Kush Parmar, M.D., Ph.D., Managing Partner at 5AM Ventures; Steven Gillis, Ph.D., Managing Director with ARCH Venture Partners, and Richard Gregory, Ph.D., Executive Vice President and Chief Scientific Officer of ImmunoGen.

The Company has also established a Scientific Advisory Board, and joining founder and SAB Chair, Dr. Chatterjee, the members include: Morton J. Cowen, M.D., pediatric immunologist, Professor Emeritus of Pediatrics and member of the Allergy, Immunology and Blood and Marrow Transplant Division in the Department of Pediatrics at UCSF Benioff Children's Hospital; Stephen J. Elledge, Ph.D., Professor of Genetics at Harvard Medical School; Mason Freeman, M.D., Professor of Medicine at Harvard Medical School and Venture Partner at 5AM Ventures; Hans-Peter Kiem, M.D., Ph.D., Associate Head, Program in Transplantation Biology, Member, Clinical Research Division, Fred Hutchinson, Professor of Medicine / Adjunct Professor of Pathology University of Washington School of Medicine and Associate Head, Heme Malignancy Program, UW / Fred Hutchinson Cancer Center and Chair of the NIH RAC, the American Society for Gene and Cell Therapy (ASGCT) Stem Cell Committee, and the American Society of Hematology (ASH) Stem Cell and Regenerative Medicine Committee.

About Homology Medicines, Inc.
Homology is a genetic medicines company translating proprietary, next generation gene editing and gene therapy technologies into novel treatments for patients with rare diseases. The combination of a management team that has successfully developed and commercialized rare disease therapies, and a new multidimensional technology platform uniquely positions the Company to move beyond the current limitations of gene therapy and editing approaches to improve patient care. Homology Medicines has built foundational intellectual property on gene editing and gene therapy using vectors derived from naturally occurring human adeno-associated viruses (AAVs). The Company's technology is precise, on-target and highly efficient for in vivo editing of genetic mutations. The unique team and technology create a significant opportunity for Homology to rapidly advance a diverse pipeline of new medicines that address and potentially cure the underlying cause of genetic diseases. For more information, please visit http://www.homologymedicines.com.

About 5AM Ventures
Founded in 2002, 5AM Ventures actively invests in next-generation life science companies. With $685 million under management, 5AM has invested in over 55 early-stage companies and its successful realizations include DVS Sciences (acquired by Fluidigm), Envoy Therapeutics (acquired by Takeda), Flexion Therapeutics, Ikaria (acquired by Mallinckrodt), Ilypsa (acquired by Amgen), Incline Therapeutics (acquired by The Medicines Company), Marcadia (acquired by Roche), Novira (acquired by J&J), Pearl Therapeutics (acquired by AstraZeneca) and Relypsa. Via its 4:59 Initiative, 5AM creates and builds therapeutics companies based on groundbreaking technologies. For more information, please visit www.5amventures.com.

About ARCH Venture Partners
ARCH Venture Partners invests in the development of seed and early stage advanced technology companies that have the potential to grow rapidly into successful businesses. ARCH invests primarily in companies that they co-found with leading scientists and entrepreneurs, concentrating on bringing to market disruptive innovations in life sciences, physical sciences and information technology, and specialize in the spaces where they converge. For more information, please visit http://www.archventure.com

About Deerfield Management
Deerfield is an investment management firm committed to advancing healthcare through investment, information and philanthropy. For more information, please visit http://www.deerfield.com.

About Temasek
Incorporated in 1974, Temasek is an investment company based in Singapore, with a S$266 billion portfolio. Temasek's portfolio covers a broad spectrum of sectors, including financial services, telecommunications, media and technology, transportation and industrials, consumer and real estate, energy and resources and life sciences and agriculture. For more information, please visit http://www.temasek.com.sg