OBJECTIVES: Use the outcomes effectiveness measure of a successfully treated patient to compare the cost-effectiveness of Eletriptan to Sumatriptan. METHODS: Data for the economic analysis was based on pooled data from three randomized, double blind, placebo-controlled phase III/B clinical trials. Logistic regression with SAS GENMOD was used to fit the model and the CONTRAST statement was used for the comparisons of interest - the numbers of successfully treated patients. Three measure of success were analyzed: patients with headache response within 2 hours of triptan therapy, sustained to 24 hours; patients with headache response within 1 hour of triptan therapy, sustained to 24 hours, and patients who were pain free within 2 hours of triptan therapy, sustained to 24 hours. The cost-effectiveness measure -cost per successfully treated patient - was calculated as a ratio of the total cost of treating all patients to the number of successfully treated patients for the comparison of Eletriptan 40mg vs. Sumatriptan 100 mg. The 95% confidence interval for the comparison group for each outcome effectiveness measure was calculated by bootstrapping techniques. RESULTS: The number of successfully treated patients for each of the 3 outcome measures of effectiveness was statistically significantly greater in the Eletriptan 40 mg groups compared to the Sumatriptan 100 mg groups (P-values all=<.002). The 95% confidence interval ranges for each of the Eletriptan cost-effectiveness results are smaller and the one for the 2-hour pain free sustained measure does not overlap that of Sumatriptan. CONCLUSIONS: The cost per successfully treated patient is a new composite outcome measure of cost-effectiveness that was consistently lower for all patients treated with Eletriptan 40 mg compared to Sumatriptan 100 mg. Cost-effectiveness using this outcome measure empirically demonstrates the value for the resources spent on migraine therapy.