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Chemistry: Generation 2+

ION363 is an investigational antisense medicine designed to reduce the production of the Fused in Sarcoma (FUS) protein.  ION363 is also known as Jacifusen (not an official USAN name) in honor of Jaci Hermstad, the first patient treated with the drug under an expanded access program. It is in development for patients with a rare genetic form of amyotrophic lateral sclerosis (ALS) caused by mutations in the FUS gene3. Mutant FUS causes motor neuron degeneration through a toxic gain of function mechanism2. In patients, mutant FUS protein aggregates in motor neurons4. Antisense-mediated reduction of mutant FUS protein in a FUS-ALS mouse model prevents motor neuron loss. It is hypothesized that reduction of FUS protein will reverse or prevent disease progression in FUS-ALS patients.

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.