A stem cell transplant procedure involves three main steps:
(1) Mobilization and Collection – Stem cells from the patient’s or donor’s bone marrow are mobilized and then collected from the blood, in a process known as apheresis. When this does not work effectively, stem cells are surgically extracted from the bone marrow.
(2) Conditioning – The patient’s stem cells must be removed from the bone marrow to make room for the new transplanted stem cells. In cases where the patient is receiving cells from a donor, the patient’s immune cells must be removed so that they do not reject the incoming healthy stem cells.
(3) Transplantation and Engraftment – Stem cells are transplanted into the patient via infusion where they migrate and take residence in the bone marrow and grow into a healthy immune and blood system free of disease.
All transplants are categorized as either autologous or allogeneic, depending on the source of the new stem cells for the transplant:
- In an autologous transplant—used for conditions such as multiple myeloma, non-Hodgkin’s lymphoma and autoimmune diseases—the patient’s own stem cells are collected and used for the transplant. In the case of stem cell gene therapy and genome editing, once the cells are collected from the patient, these cells are then modified to either insert a functioning gene into, or correct a defective gene within, the collected stem cells before they are transplanted into the patient via infusion.
- In an allogeneic transplant—used for conditions such as acute leukemias and myelodysplastic syndromes—patients receive cells from a stem cell donor. The preferred source of stem cells for an allogeneic transplant is a donor who has a well-matched immune system. Finding a well-matched donor refers to analyzing the donor’s and recipient’s human leukocyte antigens (HLA) type to determine whether they are compatible, and therefore, more likely to lead to a successful transplant and better long-term outcomes. Full HLA matches are more commonly found in a patient’s siblings. For patients without a matched related donor, a matched unrelated donor may be identified through a bone marrow donor registry.
Where Magenta’s product candidates fit in: