Zolmitriptan is effective and well tolerated in Japanese patients with migraine: a dose-response study

This phase II study investigated the efficacy, tolerability and dose-response relationship of oral zolmitriptan in the treatment of a single migraine attack in Japanese patients. A bridging analysis then assessed the validity of extrapolating western clinical data to these Japanese patients. In this multicentre, randomized, double-blind, placebo-controlled study, patients received a single dose of placebo or zolmitriptan 1, 2.5 or 5 mg. The primary endpoints were 2-h headache response and the tolerability of zolmitriptan. A statistically significant dose-response relationship was observed for the 2-h headache response (P=0.003). The 2.5 mg group had significantly greater 2-h headache response than the placebo group (P=0.032). The adverse event profile was similar to that reported in western patients, and no adverse events unique to the Japanese population were observed. The bridging analysis report confirmed similar efficacy and tolerability of zolmitriptan in Japanese and western populations. In the Japanese patients, the estimated response rates were 34.3%, 45.2%, 57.7% and 66.2% for placebo, and zolmitriptan 1, 2.5 and 5 mg, respectively, while in the western population the corresponding rates were 39.9%, 49.6%, 61.2% and 71.7%. Zolmitriptan is effective and well tolerated in the acute treatment of migraine in Japanese patients. The optimal dose was 2.5 mg, although the 5 mg dose may provide further benefit for some patients. The bridging analysis supports extrapolation of data from western to Japanese patients.