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.