Tofersen, sold under the brand name Qalsody, is a medication used for the treatment of amyotrophic lateral sclerosis (ALS). Tofersen is an antisense oligonucleotide that targets the production of superoxide dismutase 1, an enzyme whose mutant form is commonly associated with ALS. It is administered as an intrathecal injection. Tofersen is approved for medical use in the US and EU. The US Food and Drug Administration (FDA) considers it to be a first-in-class medication. Common side effects include fatigue, arthralgia, increased cerebrospinal (brain and spinal cord) fluid white blood cells, and myalgia.
Uses Tofersen is indicated to treat ALS patients associated with a mutation in the superoxide dismutase 1 (SOD1) gene (SOD1-ALS).
History Tofersen was developed by Ionis Pharmaceuticals and was licensed to and co-developed by Biogen. In February 2024, the Committee for Medicinal Products for Human Use of the European Medicines Agency adopted a positive opinion, recommending the granting of a marketing authorization under exceptional circumstances for the medicinal product Qalsody, intended for the treatment of a type of amyotrophic lateral sclerosis caused by a defective superoxide dismutase 1 (SOD1) protein. The applicant for this medicinal product is Biogen Netherlands B.V. Tofersen was approved for medical use in the European Union in May 2024. The FDA approved tofersen for priority review, orphan drug, and fast track designations.
Clinical trials Tofersen's effectiveness was evaluated in a 28-week, randomized, double-blind, placebo-controlled clinical study with 147 participants with weakness attributable to ALS and a lab-confirmed SOD-1 mutation. The study randomly assigned 108 participants in a 2:1 ratio to receive treatment with either tofersen 100 mg (n = 72) or placebo (n = 36) for 24 weeks (3 loading doses followed by 5 maintenance doses). Approximately 43% were female; 57% male; 64% White; and 8% Asian. The average age was 49.8 years (23-78). The stage III clinical trial was conducted by the Neuroscience Institute and Sheffield Institute for Translational Neuroscience (SITraN) at the University of Sheffield.
Society and culture
Economics Around 1-2% of US ALS cases carry the specific SOD1 mutation targeted by the drug. Fewer than 500 patients a year are expected to be eligible for the drug, which is expected to cost over $100,000 for a year's treatment.
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