For people with acquired aplastic anemia who are not able to have a transplant (because of age or because they do not have a matched donor), doctors will often give immunosuppressive treatment. Most cases of acquired aplastic anemia are caused by the immune system attacking the bone marrow. This treatment helps stop the immune system from killing the bone marrow cells. It is not usually helpful for cases of inherited aplastic anemia because they are not caused by the immune system.
The major drugs used are antithymocyte globulin (ATG) and cyclosporine. ATG contains antibodies against human T-lymphocytes. This medicine is given in the hospital through an intravenous (IV) line. ATG decreases (suppresses) your immune system function by lowering the number of T-cells in the body. The antibodies in ATG come from an animal (like a horse or a rabbit), so there is a risk of a serious allergic reaction when the ATG is given. Sometimes patients getting ATG also receive a corticosteroid medicine (like prednisone) to reduce the chance that a serious reaction will occur. Often the drug called cyclosporine is given as well. This drug suppresses the immune system in a different way than ATG.
Combining ATG and cyclosporine improves the blood counts in about 70% of patients with the most severe disease. The aplastic anemia may not actually be cured in most of these patients. Still, even when the blood counts do not become completely normal, they often improve enough for the patient to feel well and live a normal life. Often, after a period of remission, the aplastic anemia will come back. Usually, it will respond again to immune treatment, which can be safely repeated.
Some doctors also give a drug called G-CSF (filgrastim, Neupogen®) along with ATG and cyclosporine. This drug is a growth factor for white blood cells; it tells the bone marrow to make more of these cells. In one study, this drug helped lower the chance of a serious infection and lower the number of days that patients had to be in the hospital for their aplastic anemia treatment. However, it didn’t increase the chance that immunosuppressive therapy would be successful.
Another drug, alemtuzumab (Campath®), also can treat aplastic anemia by lowering T-cells. It is a monoclonal antibody (a man-made version of an antibody) that targets the CD52 antigen, which is found on the surface of many T-lymphocytes. This drug can help if aplastic anemia hasn’t gotten better with ATG and cyclosporine. It is also helpful to treat aplastic anemia that has come back again after treatment with these 2 drugs. It can sometimes be used instead of ATG as a part of the first treatment, but doctors aren’t sure that it works as well as ATG.. Alemtuzumab is not FDA approved to treat aplastic anemia, but it is approved to treat other diseases, such as chronic lymphocytic leukemia.
Another option for immunosuppressive therapy is to use the chemo drug cyclophosphamide in high doses. Cyclophosphamide is a chemo drug that can suppress the immune system and damage T-lymphocytes. Using it to treat aplastic anemia is controversial. Although this treatment can be effective, many experts believe that it is more dangerous than ATG. Most doctors in the United States prefer to delay using cyclophosphamide until ATG and cyclosporine are no longer working.
Immunosuppressive therapy can have serious side effects. Holding back the immune system impairs the body’s ability to fight infection. People on immunosuppression can get life-threatening infections with bacteria, viruses, and fungi.
The drugs used in this therapy also have serious side effects. For example, ATG can cause serious allergic reactions with symptoms including skin rashes, low blood pressure, and problems breathing. Generally, these side effects can be controlled with medicines. Also, about 15% of patients develop leukemia or myelodysplasia several years after getting ATG. Myelodysplasia is a disorder of the bone marrow that can turn into leukemia (see our document Myelodysplastic Syndromes.)
Side effects of cyclosporine include high blood pressure as well as kidney and liver damage. To help prevent these problems, the doctor will check the level of cyclosporine in the blood regularly. Blood tests will also be done to check kidney and liver function.
Corticosteroids (like prednisone) can cause increases in blood sugar (like diabetes), high blood pressure, weight gain, changes in mood, and weak bones.
Last Medical Review: 04/23/2013
Last Revised: 04/23/2013