Anagrelide in Essential Thrombocythemia: A Retrospective Analysis of 220 Patients. Session Type: Poster Session 646-III

This retrospective study analyses 220 patients with Essential Thrombocythemia (ET) treated with Anagrelide in 26 Institutions of the Gruppo Italiano Malattie Mieloproliferative Croniche (GIMMC). The patients, 81 males and 139 females, at diagnosis had a mean age of 39 years (13-40 years 55%; 41-60 years 35%; 61-82 years 10%) and showed a mean PLT count (109/L) of 1108, previous thrombosis (4.5%), previous hemorrhage (3%), disease related symptoms (20%), cardiovascular risk factors (32%) and splenomegaly (25%). At start of Anagrelide treatment the mean PLT count (109/L) was 907 (>1000 in 32%). The 68% of patients were receiving an antiplatelet treatment and the 74% received cytoreductive drugs (Alkylating agents and HU 17%, HU alone 20%, HU and IFN 21%, IFN alone 16%). The treatment with Anagrelide was started mainly because of the young age of patients, inefficacy and/or high dose required, toxicity and/or side effects of the other drugs and patient request. The mean daily Anagrelide dose from the baseline of 1.3 mg was increased to 1.5 mg after 1 month and to 1.8 mg since the 12th month. The most common side effects were cephalea/vertigo (24%), palpitation/tachycardia (24%), gastrointestinal (9%), asthenia (8%), oedema (5%). A transitory interruption of Anagrelide treatment was observed in 44/220 cases (20%) as a consequence of drug toxicity (3.7%), side effects (5%), no drug availability (4.5%), other causes (6.8%). A drug withdrawal was registered in 54/220 patients (24.5%) after a median treatment duration of 17 months when the mean Anagrelide dose was 1.8 mg/day and the mean PLT count was 665 x109/L), because of inefficacy (3%), toxicity (3%), side effects (9.5%), compliance loss (1%), no drug availability (3%),other causes (5%). The mean follow-up of all 220 patients was 21 months. The mean PLT count (109/L) from the baseline value of 907 decreased to 586, 505, 490, 458 and 449 after 1, 6, 12, 36 and 60 months, respectively. The mean WBC count (109/L) was 7.7 at the baseline and 9.2 after 60 months. The mean Hb level (g/dL) from the baseline of 13.2 decreased to 12.8 and 12.4 at months 6 and 60, respectively. Two minor hemorrhagic events (0.51/100 pt-yrs) and 3 major thrombotic events (0.77/100 pt-yrs) were observed during the follow-up. In this series of ET patients the treatment with the non-mutagenic Anagrelide has been confirmed to be effective and globally well tolerated. Nevertheless, new prospective studies are necessary to define the Anagrelide long-term toxicity, particularly in terms of thrombotic and/or hemorrhagic complications and anemia occurrence.