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." We performed an incremental cost-effectiveness analysis to compare anagrelide, hydroxyurea, and IFN-alpha for treating essential thrombocythemia, in terms of estimated impact on life expectancy. The case used for this analysis was of a 40-year-old man with essential thrombocythemia. Clinical assumptions were based on information obtained from nonrandomized clinical trials, and the economic assumptions were derived from information abstracted from observational studies. Lifelong treatment use of anagrelide versus hydroxyurea would cost approximately $72,000 per additional year of life gained, while the use of IFN-alpha was found to be both more costly and less effective than anagrelide. The results were very sensitive to the risk of leukemia caused by hydroxyurea, with an incremental cost-effectiveness of anagrelide compared with hydroxyurea of $156,969 per additional year of life gained if the lifetime leukemia risk drops from a baseline of .08 to.05. Given that many commonly used medical interventions cost in the range of $50,000 to $100,000 per year of life gained, and the generally poor outcome associated with treatment-related leukemia that can result from hydroxyurea, anagrelide could be considered a therapeutic alternative that is clinically effective at an acceptable cost.