Magenta Therapeutics, a new biotechnology company developing therapeutics that unlock the power of stem cell biology and bone marrow transplant, today announced the completion of a $48.5M Series A financing. The round was led by Third Rock Ventures, LLC and Atlas Venture, two firms that have built the company together over the past year with the vision to apply new stem cell science to reboot the immune and blood systems to treat patients with autoimmune diseases, genetic blood disorders and cancer.

Magenta Therapeutics aspires to develop a patient-focused set of therapeutics with the first complete platform that addresses the critical challenges in stem cell transplant. The programs could make transplants more effective for a broader range of diseases by improving patient preparation, stem cell harvesting and engraftment. This is the first time a company has taken a total approach to stem cell transplant medicine. Magenta plans to fundamentally change the use of transplant and bring this life-saving therapy to many more patients.

'Hematopoietic stem cells have the remarkable ability to develop into all cells in our blood and immune system, and have been used to transplant over one million patients in the past 50 years,' said Jason Gardner, D. Phil., chief executive officer, president and cofounder of Magenta Therapeutics. 'Technical and scientific hurdles have relegated stem cell transplantation to a last resort for deadly diseases today, but new science is ready to be advanced to the clinic that could fundamentally open up this powerful medicine to patients suffering from earlier stage cancers, blood disorders and a large set of aggressive autoimmune diseases, including multiple sclerosis and scleroderma.'

Dr. Gardner continued, 'There has been terrific innovation in stem cell science recently, and it is time to bring this forward to patients. During the past year, we have incubated Magenta with Third Rock and Atlas, and conducted extensive diligence on the key science in collaboration with many leading experts in the field. We have recruited a strong team at Magenta and are working with an experienced set of founders and advisors around an important vision in medicine. Our ultimate goal is to reboot the blood and immune systems safely to make a significant impact on the overall quality of life for a much broader group of patients that can benefit from transplant.'

Leading Scientific Cofounders

Magenta was founded by internationally recognized experts in stem cell medicine.

David Scadden, M.D., Gerald and Darlene Jordan Professor of Medicine, Professor of Stem Cell and Regenerative Biology, and chair of the Department of Stem Cell and Regenerative Biology, Harvard University; director of the Center for Regenerative Medicine, Massachusetts General Hospital; co-founder and co-director, Harvard Stem Cell Institute
Derrick Rossi, Ph.D., associate professor of Stem Cell and Regenerative Biology, Harvard University; investigator, Program in Cellular and Molecular Medicine, Boston Children's Hospital; principal faculty member, Harvard Stem Cell Institute
John Dipersio, M.D., Ph.D., professor of Medicine, Pediatrics and Pathology/Immunology, chief, Division of Oncology, Siteman Cancer Center, Barnes Jewish Hospital, Washington University St. Louis School of Medicine
Robert Negrin, M.D., professor of Medicine, Division chief of the Blood and Marrow Transplant Program; medical director of the Clinical Bone Marrow Transplantation Laboratory, Stanford University
Luigi Naldini, M.D., Ph.D., director, San Raffaele-Telethon Institute for Gene Therapy, Milan (TIGET)
Alan Tyndall, M.D., emeritus professor and head of Rheumatology, Co-founder, Basel Stem Cell Network, University of Basel
The Magenta Mission

The current standard of clinical practice for stem cell transplantation is based on science developed decades ago. With recent breakthroughs and significant clinical opportunity, Magenta aims to broaden the range of patients eligible for transplant by improving three key aspects of the procedure: patient preparation using targeted antibodies, stem cell harvesting using new biologic agents, and increasing stem cell numbers by targeting self-renewal pathways. More details of the science and programs will be forthcoming as the Company advances.

David Scadden, Magenta's chief scientific advisor, chair of the scientific advisory board and cofounder commented: 'Stem cell transplants are curative. With new gene therapy and gene editing technologies and emerging clinical experience in autoimmune diseases, more patients with more diseases can be helped or cured. We think we can make stem cell transplants safer and more efficient and change the conversation with patients from risk-focused to benefit-focused. Our goal is to make transplantation a desired early option for people with many blood and immune disorders.'

Magenta Therapeutics is led by a management team with deep scientific expertise and demonstrated success in drug discovery and development. In addition to Dr. Gardner, the company's leadership includes Michael Cooke Ph.D., chief scientific officer; Bastiano Sanna Ph.D., chief operating officer; and Christina Isacson Ph.D., vice president, head of business development. The board of directors will be led by Mike Bonney, former CEO of Cubist, as executive chairman, Alexis Borisy from Third Rock Ventures, Bruce Booth from Atlas Venture and Tom Daniel, former president of research and early development at Celgene, as independent director. These groups have been working closely together from the inception of the company and provide broad leadership and a shared vision.

The Series A round also includes GV (formerly Google Ventures), Access Industries (Blavatnik Group) and Partners Innovation Fund. Through a license agreement with Harvard University, Magenta has access to a portfolio of breakthrough stem cell technologies developed at Harvard, Massachusetts General Hospital and Boston Children's Hospital.

About Magenta Therapeutics

Magenta Therapeutics is a biotechnology company harnessing the power of stem cell science to revolutionize stem cell transplantation for patients with immune- and blood-based diseases. By creating a platform focused on critical areas of transplant medicine, Magenta Therapeutics is pioneering an integrated, but modular approach to stem cell therapies that reboot the blood and immune systems to create patient benefit. Founded by internationally recognized leaders in stem cell transplant medicine, Magenta Therapeutics was launched in 2016 by Third Rock Ventures and Atlas Venture and is headquartered in Cambridge, Mass. For more information, please visit www.magentatx.com.

About Third Rock Ventures

Third Rock Ventures is a leading healthcare venture firm focused on disruptive areas of science and medicine to discover, launch and build companies that make a dramatic difference in people's lives. By combining our team's scientific vision, strategic leadership, operational expertise and innovative deal-making capabilities, we nurture bold ideas that translate into successful business enterprises. Recognizing that the best way to create value for our investors is to create value for patients, our companies are built on a solid foundation of science, medicine, people and business strategy. For more information, please visit www.thirdrockventures.com.

About Atlas Venture

Atlas Venture is a leading biotech venture capital firm. With the goal of doing well by doing good, we have been building breakthrough biotech startups since 1993. We work side by side with exceptional scientists and entrepreneurs to translate high impact science into medicines for patients. Our seed-led venture creation strategy rigorously selects and focuses investment on the most compelling opportunities to build scalable businesses and realize value. For more information, please visit www.atlasventure.com.