Eletriptan in acute migraine: A double-blind, placebo-controlled comparison to sumatriptan

To the Editor: Goadsby et al.1 present the data of a double-blind, placebo-controlled, parallel-group comparison of the two triptans, eletriptan and sumatriptan. This comparison warrants attention. First, a double-dummy design was used in which eletriptan was compared with encapsulated sumatriptan. I question this design, as opposed to the proper (and also easier) way of conducting a comparative trial encapsulating both medications. The authors realize that it may be problematic, because “the encapsulated sumatriptan was bioequivalent to the commercial tablet (Pfizer, data on file).” How bioequivalent are the encapsulated and nonencapsulated sumatriptan preparations? Were the data obtained in a setting relevant to the study—that is, during (moderate or severe) migraine headache? Volan2 conducted ground-breaking work in the 1970s and others confirmed that the absorption of oral medications is impaired during migraine headache. Bioequivalency is essential in studies comparing a nonencapsulated product with an encapsulated one. The actual data on bioequivalency should have been presented in the article, allowing the reader to judge the degree of bioequivalency him- or herself. The second issue concerns optimum dose, which is important in comparative trials because the results are generally considered relevant only when the medications are compared in their optimum dosages. With regard to the triptans, optimum dose determination has been based on the highest effective dose with placebo-level adverse events, the lowest effective dose with maximum therapeutic benefit, or both. According to Pfaffenrath et al.,3 the optimum dose of sumatriptan was determined as 50 mg, which is both the highest effective dose with placebo-level adverse events and the lowest effective dose with maximum therapeutic benefit. At a satellite symposium of the 9th Congress of the International Headache Society (Barcelona, Spain, 1999), Jackson presented pooled data on the efficacy of eletriptan 20, 40, and 80 mg in comparison with placebo. The …