Magenta Therapeutics Presents New Preclinical Data on MGTA-145 Stem Cell Mobilization Product Candidate

CAMBRIDGE, Mass.--(BUSINESS WIRE)-- Magenta Therapeutics (NASDAQ: MGTA), a clinical-stage biotechnology company developing novel medicines to bring the curative power of bone marrow transplant to more patients, today announced that the Company highlighted new preclinical research on its MGTA-145 product candidate for stem cell mobilization in an oral presentation at the 60th annual meeting of the American Society of Hematology (ASH). MGTA-145 is being developed as a first-line agent to enable single-day mobilization of high numbers of hematopoietic stem cells for bone marrow transplant.

“Seventy percent of the bone marrow transplants performed in the US and Europe each year use mobilized peripheral blood as a source of stem cells, but current standards of care require four to six days to mobilize an adequate number of stem cells. This is a notable burden on patients, donors and healthcare resources, and the standard treatment may be contraindicated or not tolerated in some patients who need transplant,” said John Davis, M.D., M.P.H, chief medical officer, Magenta Therapeutics. “Data at ASH this year show that MGTA-145, used in combination with plerixafor, rapidly mobilizes robust numbers of stem cells that successfully engrafted in non-human primates, and the cells mobilized by the combination also blocked GvHD in a preclinical model. Based on the body of preclinical data we have seen with MGTA-145, we will be moving this program into the clinic in the first half of 2019 as a promising investigational first-line therapy for stem cell mobilization.”

MGTA-145 in Combination with Plerixafor Rapidly Mobilizes High Numbers of Hematopoietic Stem Cells and Graft-Versus-Host Disease-Inhibiting Myeloid-Derived Suppressor Cells in Non-Human Primates, Abstract #116

Key results, presented by Patrick Falahee, Ph.D., Magenta Therapeutics:

• MGTA-145 works synergistically with plerixafor, another agent for stem cell mobilization, to rapidly mobilize large numbers of stem cells.
• A single injection of MGTA-145 plus plerixafor mobilized sufficient stem cells for transplant within five hours in non-human primates.
• A single injection of MGTA-145 plus plerixafor mobilized 2 to 3 times the number of stem cells in four hours compared to the number mobilized over five days with standard of care agent G-CSF in non-human primates.
• When the cells mobilized with MGTA-145 plus plerixafor were transplanted into a non-human primate model, they rapidly engrafted.
• MGTA-145 plus plerixafor led to a 3-fold increase in immunosuppressive monocytes mobilized over G-CSF – and the mobilized cells blocked GvHD, a significant challenge in allogeneic bone marrow transplant.

About Magenta Therapeutics
Headquartered in Cambridge, Mass., Magenta Therapeutics is a clinical-stage biotechnology company developing novel medicines for patients with autoimmune diseases, blood cancers and genetic diseases. By creating a platform focused on critical areas of unmet need, Magenta Therapeutics is pioneering an integrated approach to allow more patients to receive one-time, curative therapies by making the process more effective, safer and easier.

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