A Double-Blind, Randomized, Placebo-Controlled Study to Evaluate the Effect of Intravenous BIIB023 (Anti-TWEAK) on Lower Limb Muscle Mass and Strength During and After Knee-Joint Immobilization in Healthy Male Volunteers

The primary objective of this study is to determine whether muscle atrophy induced by
immobilization of the lower limb can be attenuated by BIIB023 in healthy male volunteers. The
secondary objectives of this study in this study population are:

- To determine whether muscle weakness induced by immobilization of the lower limb can be
attenuated by BIIB023

- To assess the effect of BIIB023 on the recovery of muscle mass and strength after
immobilization

- To assess the effect of BIIB023 on histological markers of muscle atrophy and
regeneration

- To assess the effect of BIIB023 on muscle bioenergetics based on oxidative metabolism
recovery kinetics

- To evaluate the safety and tolerability of BIIB023