Biogen’s Tofersen May Show Clinical Benefit in ALS Patients with Rare SOD1 Mutations
A Particularly Uncommon Form of an Already Rare Disease
ALS is a progressive and fatal neurodegenerative disorder characterized by the destruction of motor neurons in the cerebral cortex, brain stem, and spinal cord, gradually leading to muscle atrophy and depriving patients of their ability to initiate and control voluntary movements. Most cases (approximately 90 - 95%) of ALS appear sporadically. In particular, mutations in the SOD1 gene exist in about 1-2% of patients (SOD1-ALS) without any traceable family history. The most common SOD1 gene mutations in North America are associated with younger age of onset and shorter survival, aggravating the already rare and devastating disease.
Based on the figures cited by Biogen, an estimated 168,000 people are living with ALS globally, while SOD1-ALS affects approximately 330 people in the United States.