Hydroxyurea plus aspirin best therapy in patients with essential thrombocythemia who are at high risk for vascular events

A new treatment for an incurable blood disorder proves a worse option for patients' health than an older treatment, according to a study to be presented today during the 46th Annual Meeting of the American Society of Hematology (ASH).

Essential thrombocythemia (ET), a condition in which too many platelets -- sometimes 10 times greater than normal -- are produced, affects approximately 6,000 new patients in the U.S. every year. The disorder can lead to blood clots, heart attacks, and even stroke.

"The correct management of ET has been a serious problem for hematologists because it has been very difficult to predict which patient will have a stroke or a transient ischemic attack or venous thrombosis, and then to decide on which safe treatment to use to prevent these events," said Stanley Schrier, M.D., Active Emeritus Professor of Medicine/Hematology at Stanford University School of Medicine and President of the American Society of Hematology.

With over 800 patients, most tracked for more than three years, this international, multi-center study is the largest and most comprehensive randomized study of essential thrombocythemia to date. Researchers provided patients with either anagrelide or hydroxyurea, two drugs which lower the platelet count by different mechanisms. Both groups also received aspirin, a common drug used to reduce the propensity of platelets to cause or contribute to clots.

Although the long-term control of the platelet count was comparable between the two groups, the results suggest that the disease was less well-controlled by anagrelide. Patients receiving anagrelide plus aspirin were significantly more likely to develop an obstruction in their arteries, have major hemorrhage, or develop bone marrow scarring (myelofibrosis), but were less likely to develop clots in veins. Treatment with anagrelide plus aspirin was more poorly tolerated than treatment with hydroxyurea plus aspirin, with increased rates of cardiovascular, gastrointestinal, neurological, and constitutional side effects.

Anthony Green, Ph.D., F.R.C.P., F.R.C.Path., Head of the Cambridge University Department of Haematology and lead author of the study, said, "According to our findings, hydroxyurea plus aspirin should remain the first-line therapy in patients with essential thrombocythemia who are at high risk for vascular events."

http://www.hematology.org/