Immunosuppressive drug therapy lowers your body's immune response. This prevents your immune system from attacking your bone marrow, allowing bone marrow stem cells to grow, which raises blood counts.
For older patients with acquired aplastic anemia, immunosuppressive drug therapy is the treatment of choice. It is also used for aplastic anemia patients who do not have a matched bone marrow donor. In some cases, it may be used for patients with MDS and PNH.
The three drugs used in immunosuppressive therapy include:
- Anti-Thymocyte Globulin (ATG)
- Cyclosporine
- Eltrombopag
Anti-Thymocyte Globulin (ATG)
ATG is approved in the U.S. to treat acquired aplastic anemia and to reduce the chance of organ rejection after a kidney or other organ transplant. It may also be used to treat MDS or reduce rejection after a bone marrow transplant. In the U.S., it is also sold under the brand name Atgam®.
ATG works by killing specific cells in your immune system called T-lymphocytes — the cells that are attacking bone marrow stem cells in aplastic anemia. This allows an aplastic anemia patient’s bone marrow to rebuild its supply of bone marrow stem cells, causing blood counts to go up.
Usually, ATG is given by IV infusion into a vein for 8-12 hours a day, for 4 days. The schedule depends on your needs, the type of ATG used and doctor or hospital preference. No one schedule has been shown to be better than another.
How well does it work?
When used alone, ATG improves blood counts for aplastic anemia patients about half of the time. When used with cyclosporine, ATG improves blood counts in about 7 out of 10 cases. When a platelet growth factor called eltrombopag (Promacta®) is also given, more than 7 in 10 people see improved blood counts.
If it works, ATG usually stops the need for blood transfusions within 3 months. Full success can take at least 9 months. Some patients may respond initially, but may later relapse and need another treatment.
What are common side effects?
When receiving the treatment, some common side effects are:
- Chills
- Fever
- Hives
- Nausea
- Vomiting
- Diarrhea
- Dizziness
- Headache
These side effects usually go away after treatment.
Horse vs. Rabbit ATG
ATG is created injecting human white blood cells (T cells) into a horse or a rabbit, and extracting the antibodies produced. A recent study conducted by the National Institutes of Health (NIH) found that horse-derived ATG provided a better overall response rate in aplastic anemia patients. In other words, patients who took horse ATG had increased blood counts, and the counts stayed up longer when compared to patients given rabbit ATG. Learn more about this study
Cyclosporine
Cyclosporine prevents T-lymphocytes, a type of white blood cell, from becoming active. Once the T-lymphocytes are turned off by the cyclosporine, they stop attacking stem cells in the bone marrow. In aplastic anemia patients, this allows bone marrow stem cells to grow back and start making blood cells again.
Cyclosporine is typically used in combination with ATG to treat acquired aplastic anemia. It is also used to prevent rejection after an organ transplant and to reduce immune response after a bone marrow transplant.
Cyclosporine comes in liquid and pill forms. The first dose is based on how much you weigh. Later doses depend on the amount of cyclosporine in your blood. Too little cyclosporine will not work; too much will cause side effects. If you are responding well to cyclosporine, your doctor may decrease your dose over time.
How well does it work?
When used alone, cyclosporine is less effective than ATG. When used with ATG, cyclosporine improves blood counts in about 7 out of 10 cases of acquired aplastic anemia.
What are common side effects?
Some common side effects include:
- Tremors or shaking
- Nausea
- Diarrhea
- High blood pressure
- Kidney problems
- Loss of magnesium or potassium
- Liver inflammation
- Increased hair growth
- Gum swelling and pain
These problems can usually be fixed by taking medicine to lower your blood pressure and by replacing the lost magnesium or potassium.
Eltrombopag
Eltrombopag (Promacta) is used to increase the number of platelets (cells that help blood clot) and to decrease the risk of bleeding. It is a man-made platelet growth factor that signals your bone marrow to make more platelets. Eltrombopag was approved by the U.S. Food and Drug Administration in 2014 to treat refractory aplastic anemia. In 2018, Eltrombopag was FDA approved as a first line therapy to treat aplastic anemia. It comes as a tablet and as a powder for oral suspension (liquid) to take by mouth.
What are the possible side effects of eltrombopag (Promacta)?
Get emergency medical help if you have any of these signs of an allergic reaction: hives; difficult breathing; swelling of your face, lips, tongue, or throat.
Stop using eltrombopag and call your doctor at once if you have:
- pain or burning when you urinate;
- fever, chills, body aches, flu symptoms, unusual weakness or tired feeling;
- nausea, upper stomach pain, itching, loss of appetite;
- dark urine, clay-colored stools;
- jaundice (yellowing of the skin or eyes);
- pain, swelling, warmth, or redness in one or both legs