Dr. Amitabha Mazumder
Professor, New York University School of Medicine
Adult stem cell transplants (also referred to as bone marrow transplants) have been used for over 40 years in successfully treating cancers such as leukemia, multiple myeloma and lymphomas, and research has now opened the doors to regenerative and reparative therapeutics.
There are three different categories of patients who would benefit from stem cell transplants:
• Those patients who don’t have stem cells, or if a patient’s bone marrow stops working and doesn’t produce enough healthy stem cells. Example – patients with aplastic anemia, a severe blood disease, where the myeloid stem cells are absent.
• Patients who suffer from genetic diseases where the stem cells are present, but are considered “defective,” including sickle cell disease and certain autoimmune disorders.
• Cancer patients. When you are using the patient’s own cells in an autologous setting (using your own cells), you are replacing blood-forming cells destroyed by cancer treatments. The goal of a stem cell transplant is to help the bone marrow recover and continue to make healthy blood cells.
Perhaps the area where stem cell transplants have made the most headway is for cancer patients. Stem cell transplants have cured thousands of patients with what were thought to be incurable cancers. These patients would normally be dying and are essentially being rescued by autologous stem cell transplants.
As the results of the research become more definitive, we are starting to view autologous stem cell transplants as a
way to reset the clock, for example, in the immune system. We are continuing to build our research efforts on these earlier successes. In an allogeneic transplant (using somebody else’s cells), donor cells are intended to provide the patient with new blood cells and a new immune system. The donor cells are obtained from a Human Leukocyte Antigens (HLA) matched individual, and may be obtained from cord blood; a related donor who is a match (based on HLA, the genetic markers of the immune system); or from unrelated donors.
An exciting part of an allogeneic stem cell transplant is that we can now understand that the cells that we’re giving to the patient are the cells that are actually doing the work of destroying the cancer cells. So we don’t have to blast the patient with high doses of chemotherapy or radiotherapy. These cells are actually going in and they’re creating what we call a graft vs. leukemia or graft vs. tumor response. This enables us to be able to do the procedure in an utpatient setting with very low doses of chemoradiotherapy. We can infuse these cells in and let them do their work. We can do the procedure in 70-75 year olds; we can do it in patients who have renal, heart or lung dysfunction. And this process has markedly enhanced the cure rate of a lot of patients.