Biogen Inc. announced topline results from its pivotal Phase 3 VALOR study of tofersen (BIIB067), an investigational antisense drug being evaluated for people with superoxide dismutase 1 (SOD1) amyotrophic lateral sclerosis (ALS). While tofersen did not meet the primary endpoint of change from baseline to week 28 in the Revised Amyotrophic Lateral Sclerosis Functional Rating Scale (ALSFRS-R), trends favoring tofersen were seen across multiple secondary and exploratory measures of biologic activity and clinical function. In addition, a pre-specified integration of data from VALOR and its ongoing open-label extension study (OLE) reinforced these findings and showed that early tofersen initiation led to less decline across multiple measures of motor function, respiratory function, muscle strength, and quality of life in people with SOD1-ALS. Most adverse events in both VALOR and OLE were mild to moderate in severity, including procedural pain, headache, pain in extremity, fall and back pain. Biogen is actively engaging with regulators, the medical community, patient advocacy groups and other key stakeholders around the world to determine potential next steps. ALS is a progressive neurodegenerative disease that is uniformly fatal with an average survival of three to five years. The most common cause of death is respiratory failure. SOD1-ALS is a rare, genetic form of ALS that accounts for approximately two percent of the estimated 168,000 people who have the disease globally. Currently, there are no genetically targeted treatment options for ALS.