FUSION: A Study to Evaluate the Efficacy, Safety, Pharmacokinetics and Pharmacodynamics of ION363 in Amyotrophic Lateral Sclerosis Participants With Fused in Sarcoma Mutations (FUS-ALS)

This is a multi-center, three-part study of ION363 in up to 95 participants. Part 1 will consist of participants who will be randomized in a 2:1 ratio to receive a multi-dose regimen of ION363 or placebo for a period of 60 weeks, followed by Part 2, in which participants will receive open-label ION363 for a period of 84 weeks. Participants may continue to receive open-label ION363 in Part 3 for up to 3 additional years or until ION363 becomes commercially available in the patient's country or until the Sponsor discontinues the ION363 development program, whichever occurs earlier.