A long-term study of young patients with essential thrombocythemia treated with anagrelide
Mazzucconi, M.Gabriella.; Redi, R.; Bernasconi, S.; Bizzoni, L.; Dragoni, F.; Latagliata, R.; Santoro, C.; Mandelli, F.
Haematologica 89(11): 1306-1313
2004
ISSN/ISBN: 0390-6078 PMID: 15531452 Document Number: 582581
Background and Objectives. Essential thrombocythemia (ET) can be complicated by lifethreatening thrombosis and has a risk of converting into acute leukemia. Cytoreductive therapy may reduce the risk of thromboembolic complications. Herein, we report the results of a long-term study of patients with ET treated with anagrelide to control thrombocytosis. Design and Methods. Thirty-nine (34 evaluable) patients (median age, 33 years; 24 previously untreated) were enrolled between 1989-1996; the mean platelet count prior to therapy was 1197x109/L. Only 9 out of 34 evaluable patients were at high risk of thrombosis (platelet count more than 1500x109/L). The initial dose of anagrelide (0.5 mg/bid for 7 days) was increased by 0.5 mg/day (maximum dose: 3 mg/day) until a response was seen. Results. A complete response (platelets < 450x109/L for >1 month) was seen in 15/34 (44%) patients and a partial response (platelets 450-600x10'/L9 for >1 month) was seen in 17/34 ( 50%), so that the some kind of response was seen in 32/34 (94%) of the patients at a median time of 4.2 months after starting treatment. Seventeen patients (50%) are still being treated and have achieved platelet control for a maximum follow-up of 12.5 years. Late onset anemia occurred in 4/39 patients. Three out of 39 patients (8%) had cardiac disorders. Interpretation and Conclusions. Anagrelide appears suitable for controlling thrombocytosis in ET patients over the long-term. This drug may be used in patients younger than 60 years, with the exclusion of women of child-bearing potential and subjects aged 40-60 years with a history of major thrombotic events. Anagrelide should not be administered to patients with cardiac disorders, and a careful approach to patients should include monitoring of heart function before and during treatment.