Comparing Therapies for the Treatment of Severe Aplastic Anemia
Status:
Completed
Trial end date:
2008-03-03
Target enrollment:
Participant gender:
Summary
Severe Aplastic Anemia (SAA) is a rare and very serious blood disorder in which the bone
marrow stops producing the cells which make up blood; red blood cells, white blood cells, and
platelets.
Researchers believe this is caused by an autoimmune reaction, a condition in which the
natural defense system of the body begins attacking itself. In SAA the immune system begins
attacking the bone marrow. Red blood cells are responsible for carrying oxygen to all of the
organ systems in the body, and low numbers (anemia) can cause difficulty breathing and
fatigue. Platelets are responsible for normal blood clotting and low numbers can result in
easy bruising and bleeding which can be deadly. White blood cells are responsible for
fighting infections, and low numbers of these can lead to frequent infections, the most
common cause of death in patients with aplastic anemia.
SAA can be treated by bone marrow transplant (BMT) or by drugs designed to slow down the
immune system (immunosuppressants). BMT can be successful, but it requires a donor with
matched bone marrow, making this therapy available only to a few patients. BMT with unmatched
bone marrow can fail and cause dangerous side effects.
Presently, the two drugs used to treat SAA by slowing down the immune system
(immunosuppression) are antithymocyte globulin (ATG) and cyclosporin A (CSA). When used in
combination these two drugs can improve most patients condition. However, one third of the
patients who respond to this therapy experience a relapse of SAA. In addition, some patients
treated with ATG/CSA can later develop other disorders of the blood.
Recently, researchers have found that another immunosuppressive drug called cyclophosphamide,
has been successful at treating patients with SAA. In addition, patients treated with
cyclophosphamide do not experience relapses or develop other disorders of the blood.
In this study researchers would like to compare the combinations of antithymocyte globulin
(ATG) and cyclosporin A (CSA) to cyclophosphamide and cyclosporin A (CSA) for the treatment
of SAA.