This study has 2 phases (the Food Phase and the Antacid Phase), each consisting of a 2-period, 2-sequence, 2-treatment crossover design. The Food Phase will assess the effect of a high fat meal on the pharmacokinetics of 100 mg BIIB021, and the Antacid Phase will assess the effect of an antacid (ranitidine) on the pharmacokinetics of 450 mg BIIB021 in the same subjects. Ranitidine 150 mg will be taken the evening before and the morning of the antacid dosing day.
This study is designed to assess the effect of food and antacid use on the pharmacokinetic properties of BIIB021.