Treatment of Children with Anagrelide for Essential Thrombocythemia

Kim, Ji Yoon; Lee, Kun Soo

Abstract

PURPOSE
Essential thrombocythemia (ET) in children is a rare myeloproliferative disease characterized by persistent elevation of platelets and is associated with an increased risk of thrombohemorrhagic complications. For patients with risk factors, cytoreductive therapy is important to reduce the risk for thrombotic or hemorrhagic events. However, the frequent side effects and the carcinogenic potential of many cytoreductive agents, such as hydroxyurea, limit their use, especially in younger patients. Anagrelide has selective activity against platelet production as well as tolerable toxicity, noncarcinogenic effect and the advantage of oral administration. But, the experience with anagrelide in pediatric patients with ET is limited. METHODS: Four children were diagnosed as ET according to the criteria of the Polycythemia Vera Study Group, at the Department of Pediatrics, Kyungpook National University Hospital in Daegu, Korea from January 1998 to February 2004. After informed consent was obtained from the parents, therapy with anagrelide (induction dose 1~1.5 mg/day, maintenance dose 1 mg/day) was started in three of the four children who had been treated with hydroxyurea. RESULTS: All children had responded well to the anagrelide therapy without significant side effect. CONCLUSION: Anagrelide, a noncarcinogenic agent, seems to be a promising alternative to conventional cytoreductive treatment for children with ET. Additional experience with more asymptomatic and symptomatic children with ET should be reported, with close monitoring of the treated children with anagrelide for early and late side effects.