The objective of this early access program (EAP) is to provide access to tofersen to eligible participants with amyotrophic lateral sclerosis (ALS) associated with a mutation in the superoxide dismutase 1 (SOD1) gene prior to an alternative access mechanism in order to address a high unmet medical need in this population.

Treating healthcare professionals (HCPs) of participants who meet the inclusion/exclusion criteria may request access by emailing medicineaccess@clinigengroup.com. The current EAP structure does not limit participants to receive access at specific sites. Treating HCPs can submit requests on behalf of participants by emailing Clinigen at the email address provided below. Information on the EAP eligibility criteria, including participants and center criteria, will be provided by Clinigen as part of the enrollment request process.

Key Inclusion Criteria:

• Medically able to undergo the program procedures, as determined by the treating healthcare professional (HCP).
• Weakness attributable to ALS and associated with a mutation in the SOD1 gene (SOD1-ALS).

Key Exclusion Criteria:

• Previous or current participation in a clinical trial of tofersen.
• Use of an investigational medicinal product (IMP) for amyotrophic lateral sclerosis (ALS) within 5 half-lives of the IMP before the first dose of tofersen.
• Participant's primary place of residence is outside of the country of treatment.

NOTE: Other protocol defined Inclusion/Exclusion criteria may apply