[The effectiveness of anagrelide treatment in patients with Ph negative myeloproliferative diseases: influence on the incidence of thrombosis in the data from the Registry of patients with essential thrombocythemia and thrombocythemia associated with other myeloproliferative diseases treated with Thromboreductin® to the end of 2012]

In the Czech Republic, anagrelide (Thromboreductin®) [29] is used according to the recommendations of the Czech Working Group on Myeloproliferative Disorders (CZEMP) for treatment of thrombocythemia associated with Ph negative myeloproliferative disorders (MPDs). The patient data are collected in the Registry of patients with essential thrombocythemia (ET) and thrombocythemia associated with other MPDs treated with Thromboreductin®. At the end of 2012, the Registry contained data on 1,161 patients. Out of these, 1,159 patients with the dia-gnosis of a Ph negative MPD were evaluated. In 844 patients, precise WHO based dia-gnosis was known at start of therapy: 442 (52.4%) had ET, 108 (12.8%) had polycythaemia vera (PV) and 243 had primary myelofibrosis (PMF). The median age was 51 years at the time of diagnosis. At the time of the evaluation of the population, the median was 59 years. Every year, the proportion of patients newly treated with anagrelide as a firstline treatment in accordance with the CZEMP guidelines has been increasing. A growing proportion of patients has been treated with an additional cytoreducing drug, such as hydroxyurea and interferon. The majority of the patients received also an antiaggregant (or anticoagulant). More than a half of patients harbors the JAK2 mutation. A prompt decrease of platelet counts (as the response to Thromboreductin® treatment) was documented in most of the patients. After one year, 86.9% of patients had a full or partial response. In poorer responders, combination cytoreductive treatment was administered rather then the escalation of the Thromboreductin® dosage. There were 461 thrombotic manifestations in 363 patients and 61 haemorrhagic events in 57 patients recorded in the patients history. In the course of treatment (followup; F U), thrombosis was diagnosed only 179-times in 136 patients. There were more haemorrhagic events during F U: 109 events in 83 patients. Upon comparison of the number of events during F U to their numbers in history, we found a twofold decrease in arterial thrombosis, an almost twofold decrease in microvascular thrombosis and even a 6.6- fold decrease in venous thromboembolism events. Bleeding episodes increased 1.8-fold during F U. However, the vast majority of these hemorrhagic events were clinically insignificant. In conclusion, the treatment strategy according to the CZEMP guidelines incorporating anagrelide is highly effective in reducing the platelet counts, strongly prevents venous events, reduces arterial events, and leads to an increase of minor hemorrhages.