The primary objective of the study is to evaluate the long-term safety and tolerability of
BIIB067 in participants with amyotrophic lateral sclerosis (ALS) and confirmed superoxide
dismutase 1 (SOD1) mutation. The secondary objectives are to evaluate the pharmacokinetic
(PK), pharmacodynamic (PD), biomarker effects, and efficacy of BIIB067 administered to
participants with ALS and a confirmed SOD1 mutation.