CAMBRIDGE, MA, USA I January 25, 2023 I Magenta Therapeutics (Nasdaq: MGTA) today announced that the latest participant dosed at the Cohort 3 level (0.08 mg/kg) in the ongoing MGTA-117 Phase 1/2 Dose-Escalation Clinical Trial in relapsed/refractory acute myeloid leukemia (AML) and myelodysplastic syndrome (MDS) experienced a Grade 5 Serious Adverse Event (SAE) (respiratory failure and cardiac arrest resulting in death) deemed to be possibly related to MGTA-117. The known information has been reported to the U.S. Food and Drug Administration (FDA) as a Suspected Unexpected Serious Adverse Reaction (SUSAR). After consultation with the trial’s safety Cohort Review Committee and with the highest regard for patient safety, Magenta has voluntarily paused dosing in the clinical trial and is working to evaluate the totality of available data and determine next steps for the development of MGTA-117.

About Magenta Therapeutics
Magenta Therapeutics is a clinical-stage biotechnology company developing medicines designed to bring the curative power of stem cell transplant to more patients with blood cancers, genetic diseases and autoimmune diseases. Magenta is combining leadership in stem cell biology and biotherapeutics development with clinical and regulatory expertise to revolutionize blood and immune reset to allow more patients to take advantage of the curative potential of stem cell transplant and potentially improve eligibility for future gene therapies.

Magenta is based in Cambridge, Mass. For more information, please visit

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SOURCE: Magenta Therapeutics