Allogeneic Bone Marrow Transplant: Bone Marrow Transplantation for AML
What This Article Covers:
What Is an Allogeneic Bone Marrow Transplant?
An allogeneic bone marrow transplant takes healthy stem cells from a donor and gives them to the transplant patient. The stem cells can be harvested from donated umbilical cord blood or from an adult donor. The stem cells from the transplant will then grow and mature into new healthy stem cells. An allogeneic bone marrow transplant is also sometimes called an allogeneic stem cell transplant.
Other Diseases a Bone Marrow Transplant is Used for:
Bone marrow transplants are a common AML (acute myeloid leukemia) treatment option for patients, but can also be used to treat a variety of other conditions that affect either the blood or bone marrow including:
- Aplastic anemia
- Bone marrow failure syndromes
- Chronic leukemia
- Hodgkin’s lymphoma
- Immune deficiencies
- Inborn errors of metabolism
- Multiple myeloma
- Myelodysplastic syndromes
- Non-Hodgkin’s lymphoma
- Plasma cell disorders
- POEMS syndrome
- Primary amyloidosis
How Is a Donor for a Bone Marrow Transplant Identified?
Tissue typing for allogeneic bone marrow transplants helps to identify the proteins present in the patient’s blood called antigens. These antigens help the body identify what tissues are part of the body, and what are invaders (like bacteria and viruses). If a transplanted organ doesn’t match these antigens, then the body may identify it as a foreign invader and begin attacking the transplanted organs. The same can occur with the blood and bone marrow cells that are donated in a transplant.
HLA typing or tissue typing involves the identification and matching of six of these antigens, called the A, B and DR antigens. There are two antigens for each letter and they are identified by numbers for a total of six antigens that are vitally important in the transplantation process. These antigens are inherited from your parents, three antigens from each parent. Siblings have a 25% chance of inheriting the same six antigens, which is why siblings are often a good potential donor candidate for a transplant.
The bone marrow transplant donor can be a relative or someone who is unrelated but is a HLA (human leukocyte antigen) match. A close HLA match helps lower the risk of problems post transplant and the instance of graft vs host disease. While 70% of patients who need a bone marrow transplant do not have a HLA match in their family, registries can often match patients with unrelated transplant donors or donated umbilical cord blood that are a match.
What are the steps of a Bone Marrow Stem Cell Transplant?
A stem cell transplant is a long process that typically involves several steps:
- Tests before the Transplant Process Begins: The stage of AML, overall patient health, and other important health metrics will be assessed before the transplant process begins.
- Donor Match for the Transplant: A suitable donor must be identified through an HLA match and stem cells to be used for the transplant will be harvested from the donor’s body.
- Conditioning of the Patient before the Transplant Process Begins: The patient will be prepared for the transplant process. This may include chemotherapy to help kill the abnormal stem cells.
- Transplantation: The donor’s stem cells are transplanted intravenously into the patient’s bloodstream.
- Engraftment: The donor stem cells travel to the bone marrow and begin to produce new, healthy blood cells.
- Recovery from the Transplant: The patient may spend several weeks in the hospital to monitor the engraftment process and overall patient health post transplant.
What are the Risks Associated with a Stem Cells Transplant
There are many complications that can arise from an allogeneic transplant. Factors such as the patient’s age, overall health status and the variance of tissue match between the donor and recipient will all affect the possibility of complications from the transplant. Common physical complications of an allogeneic transplantation include:
- Nausea and vomiting
- Hair loss
- Loss of Appetite
- Emotional Issues
- Graft Versus Host Disease
How is an Allogeneic Bone Marrow Transplant Performed?
Allogeneic bone marrow transplants are performed by using a donor’s stem cells (blood-forming cells) to replace the stem cells that have been destroyed by chemotherapy in the patient’s body. The donated stem cells are harvested from a site on the donor’s body that contains a lot of marrow, typically the back of the hips. The donor will receive general anesthesia before undergoing the harvesting operation, and is typically sore for about a week at the harvest site.
Donor stem cells are then frozen and stored as the recipient is prepared for the procedure. The recipient typically undergoes chemotherapy and or radiation therapy to kill the diseased stem cells in their body. The allogeneic transplant is then typically performed like a blood transfusion in which the new stem cells are added to the recipient’s bloodstream through a tube.
What is the difference between an autologous and allogeneic bone marrow transplant?
The main difference in an autologous and allogeneic bone marrow transplant procedure is the source of the stem cells. In an autologous bone marrow transplant, the stem cells are sourced from the patient, whereas in allogeneic transplants, the donor is either a related or unrelated person who is a match. An unrelated marrow donor is usually identified through a national marrow donor program such as Be the Match. The donor can also come from a registry of donated cord blood. An autologous stem cell transplant is not used in most AML cases.
In both autologous and allogeneic blood and marrow transplantation, the donor is typically given medications to increase the number of stem cells circulating in the bloodstream, where these cells can be more easily collected.
What is the success rate of allogeneic stem cell transplant for AML?
While all AML outcomes depend very heavily on factors that include the overall health of the patient, the patients’ age and any extenuating circumstances, a 2016 study found that the 5-year survival rate for patients that received an autologous bone marrow transplant was 65% and for those who received an allogeneic transplant it was 62%.
What to Expect after an allogeneic bone marrow transplant
Blood counts may take 6-12 months to recover to normal levels after a transplant. This means your immune system will still be compromised following a transplant. Your healthcare team will continue to monitor your progress as you make your recovery. Most patients experience physical weakness including extreme fatigue, nausea or vomiting post transplant.
When Are Bone Marrow Transplants for AML Used?
Chemotherapy is the main form of treatment for AML, however, often transplantation of bone marrow and stem cells can help patients tolerate a higher dose of chemotherapy or recover from the serious side effects that are associated with chemotherapy treatments. A transplant is often used in AML treatment when the initial chemotherapy does NOT lead to remission of the patient’s AML symptoms.
Where Does Sierra Trial Come In?
- 131I apamistamab (Iomab-B) is the subject of a research clinical trial. It is an investigational drug (not approved by the FDA) that targets bone marrow and blood cancer (leukemia) cells. It is used to help patients get ready for bone marrow transplant (BMT) also known as hematopoietic stem cell transplantation (HSCT). A bone marrow transplant remains an important, potentially curative option.
- 131I apamistamab (Iomab-B) is a targeted therapy being developed for AML.131I apamistamab (Iomab-B) delivers radiation preferentially to your bone marrow and spleen, where most leukemia cells are, when compared to other organs such as liver, lungs, kidneys and mucous membranes that can be harmed by too much radiation.
- 131I apamistamab (Iomab-B) may allow some patients with relapsed or refractory Acute Myeloid Leukemia to get a transplant.