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Chemistry: Generation 2+

ION541, also known as BIIB105, is an investigational antisense medicine targeting ataxin 2 (ATXN2) RNA. ION541 is designed to reduce the production of ATXN2 protein. It is in development as a potential therapy for patients with most forms of Amyotrophic Lateral Sclerosis (ALS), regardless of family history. Aggregates of TDP-43 protein in motor neurons is a pathology common to more than 90 percent of the ALS population and induces toxicity in motor neurons. ATXN2 has been shown to modulate TDP-43 toxicity2-3. In addition, human genetic data has also identified a link between ATXN2 and ALS4. It is hypothesized that reduction of ATXN2 will ameliorate the underlying TDP-43 pathology and reverse or prevent disease progression, therefore providing therapeutic benefit to most ALS patients1.

About Amyotrophic Lateral Sclerosis

ALS is a rare, fatal neurodegenerative disorder characterized by loss and dysfunction of neurons in motor pathways. It is estimated that there are ~55,000 patients diagnosed with ALS in major markets1. Approximately 90 percent of patients with ALS have no known family history, while approximately 10 percent of patients have a known genetic cause for their disease. People with ALS suffer progressive degeneration of motor neurons, which results in a declining quality of life due to muscle weakness, loss of movement and difficulty in breathing and swallowing. Currently, treatment options for patients with ALS are extremely limited with no drugs that significantly slow disease progression.