Hydroxyurea Compared with Anagrelide in High-Risk Essential Thrombocythemia

The major risks in essential thrombocythemia are thrombosis and hemorrhage. In this large, randomized trial, the patients given anagrelide plus aspirin had higher rates of arterial thrombosis and serious hemorrhage, whereas the hydroxyurea group had a higher rate of venous thromboembolism. The rate of transformation to myelofibrosis was higher in the anagrelide group. In this trial, patients given anagrelide plus aspirin had higher rates of arterial thrombosis and serious hemorrhage, whereas the hydroxyurea group had a higher rate of venous thromboembolism. The principal feature of essential thrombocythemia, a clonal hematologic stem-cell disorder, 1 – 4 is thrombosis, with arterial events being more common than venous events. Hemorrhage also occurs, particularly if the platelet count is very high. In the long term, some cases transform to myelofibrosis, myelodysplasia, or acute myeloid leukemia. Factors that increase the risk of thrombosis are an age of more than 60 years, prior thrombosis, and, to a lesser extent, cardiovascular risk factors. 5 – 7 The importance of the platelet count as a risk factor is unclear, but a reduction in platelet count reduces the frequency of thrombosis, and aspirin relieves . . .