Beginning in mid-July 2021, Biogen is opening part 1 of its early access program for the investigational therapy tofersen to individuals with amyotrophic lateral sclerosis (ALS) caused by mutation of the superoxide dismutase 1 gene (SOD1) who are specifically experiencing rapid disease progression. Tofersen is being investigated in a phase 3 clinical study for safety and efficacy, and the . . .