A long-term study of young patients with essential thrombocythemia treated with anagrelide.
OBJECTIVE
Essential thrombocythemia (ET) can be complicated by life-threatening 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.


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 1197x10(9)/L. Only 9 out of 34 evaluable patients were at high risk of thrombosis (platelet count more than 1500x10(9)/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 < 450x10(9)/L for >1 month) was seen in 15 /34 (44%) patients and a partial response (platelets 450-600x10(9)/L 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.


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.
Mazzucconi
Maria Gabriella
MG
Hematology Department of Biocellular Technology and Hematology, La SapienzaUniversity, Rome, Italy. mazzucconi@bce.med.uniroma1.it <mazzucconi@bce.med.uniroma1.it>
Redi
Roberta
R
Bernasconi
Sayla
S
Bizzoni
Luisa
L
Dragoni
Francesco
F
Latagliata
Roberto
R
Santoro
Cristina
C
Mandelli
Franco
F
D000328:Adult; D000740:Anemia / Q000139:chemically induced; D005260:Female; D006454:Hemoglobins / Q000032:analysis; D006801:Humans; D008297:Male; D008875:Middle Aged; D010975:Platelet Aggregation Inhibitors / Q000009:adverse effects / Q000627:therapeutic use*; D011799:Quinazolines / Q000009:adverse effects / Q000627:therapeutic use*; D013272:Stomach Diseases / Q000139:chemically induced; D013610:Tachycardia / Q000139:chemically induced; D013920:Thrombocythemia, Essential / Q000188:drug therapy*; D013997:Time Factors
D006454:Hemoglobins; D010975:Platelet Aggregation Inhibitors; D011799:Quinazolines; C021139:anagrelide