Cost-effectiveness considerations in the treatment of essential thrombocythemia.

Factors that influence the choice of anagrelide, hydroxyurea, or interferon-alfa (IFN-alpha) for treatment of essential thrombocythemia include efficacy, toxicity, and cost. Anagrelide has the US Food and Drug Administration's approval to be used for treating patients with thrombocythemia secondary to chronic myeloproliferative disorders. In contrast, the use of IFN-alpha and hydroxyurea are considered "off-label.