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New Treatments for Essential Thrombocythemia

When dealing with a patient with thrombocytosis you have to consider the possibility that this could be reactive, or it could be accounted for from any other disease other than essential thrombocythemia. You have to rule out these first and then rule these out. If the thrombocytosis is associated with an unusual bleeding or thrombosis, that increases your suspicion that this is indeed ET or essential thrombocythemia, excessive platelet count.

Now if you donít find any of that, then you have to do a bone marrow. You have to do the bone marrow. And what you can find in the bone marrow in ET is these abnormal megakaryocyte clusters. Sometimes you can see a mild reticulin fibrosis. Less than 5% of time you can see cytogenic abnormalities. But these things are whatís sensitive, what is suggested.

Smoking is the major risk factor for thrombosis in ET. Itís been shown in several studies. If they are at high risk and they are over age 60, then I donít think you really need to worry too much about the potential leukemogenicity of hydroxyurea. Itís a very well-tolerated drug. If they are high risk and they are under age 60 then this hydroxyurea and leukemia business comes up. Now, if people want to treat this with hydroxyurea I think I will go and testify for them that it was appropriate. If they want to treat with anagrelide, I think that is a very reasonable alternative. I donít thing one can say that this is better than this. The patients will tell you which one is better because they will have side effects.

If they are intermediate risk, thatís kind of difficult. I tell them not to smoke - easy thing first. If their platelet count is less than 1.5 million I usually just put them on low- dose aspirin and leave them alone. Why less than 1.5 million? Because a platelet count of over 1.5 million has been associated with increased bleeding tendency. If you have to treat, perhaps you may sleep better if you use anagrelide rather than hydroxyurea. However, hydroxyurea is not always tolerable and you can have very painful leg ulcers.

Now there are about 10% of patients who get fluid retention and perhaps some congestive heart failure, and very rarely cardiomyopathy has been seen with the use of anagrelide. So if you have patients with heart problems, I think you are probably better off not using anagrelide and going with hydroxyurea.