Dr Cantor raises several relevant questions regarding the post hoc analysis comparing AA and WA patients with multiple sclerosis and their responses to interferon beta-1a treatment from the EVIDENCE trial. The first question asks whether the difference observed between the 2 groups could be accounted for by differences in the proportions of patients treated with once weekly vs thrice weekly interferon beta-1a. We addressed this issue by performing multivariate analysis that adjusted for treatment and reported comparable results to the unadjusted analysis. We conclude that the differences observed between the 2 groups were not accounted for by differences in the dose and frequency of interferon beta-1a administration.
Cree BAC. Interferon Beta-1a Treatment and African Americans—Reply. Arch Neurol. 2006;63(4):628. doi:10.1001/archneur.63.4.628-a