Avidity Unveils Groundbreaking AOC 1020 Phase 1/2 Trial Results for Facioscapulohumeral Muscular Dystrophy

Avidity Biosciences, Inc., a biopharmaceutical firm known for its RNA therapeutics called Antibody Oligonucleotide Conjugates (AOCs™), recently shared promising initial data from its Phase 1/2 FORTITUDE™ trial. This trial evaluates delpacibart braxlosiran (AOC 1020), the first investigational treatment aimed at addressing the root cause of facioscapulohumeral muscular dystrophy (FSHD). FSHD is a rare genetic disorder marked by progressive muscle weakness, significant pain, and disability.

Delpacibart braxlosiran, or "del-brax," targets the abnormal expression of the DUX4 gene, which is responsible for the muscle degeneration seen in FSHD. Early data from the trial shows a consistent reduction of over 50% in DUX4 regulated genes among participants. This reduction is paired with trends indicating improvements in muscle strength, reachable workspace, and quality of life, with all adverse events being mild or moderate in nature.

Dr. Jeffrey M. Statland from the University of Kansas Medical Center, a principal investigator in the FORTITUDE trial, expressed optimism about these early results. The data showing trends of functional improvements are particularly encouraging for FSHD patients, who currently have no approved treatments available.

The FORTITUDE trial is a randomized, double-blind, placebo-controlled study involving 39 adult participants with FSHD. Participants received either del-brax or a placebo to evaluate safety, tolerability, and preliminary activity of the treatment. At the four-month mark, data from 12 participants in the 2 mg/kg cohort showed significant reductions in DUX4 regulated genes, indicating the treatment’s potential effectiveness.

Sarah Boyce, Avidity’s President and CEO, emphasized the urgency of developing a treatment for FSHD. She pointed out that del-brax, by directly targeting DUX4, holds the promise of being the first and best-in-class therapy for this debilitating disease. Boyce also highlighted that this is Avidity’s third rare muscle disease program to demonstrate positive delivery to muscle and functional improvement, affirming the potential of their AOC platform.

The initial data from the FORTITUDE trial will be presented at the 31st Annual FSHD Society International Research Congress in Denver, Colorado. This presentation will further detail the safety and effectiveness of del-brax in reducing DUX4 expression and improving muscle function.

Mark Stone, CEO of the FSHD Society, noted the significant impact of these findings for those living with FSHD. The disease’s progression often severely limits everyday activities and social interactions, making any potential treatment a beacon of hope for patients and their families.

The FORTITUDE trial’s primary goal is to evaluate the safety and tolerability of del-brax. Secondary objectives include assessing the drug's impact on muscle volume, composition, and functional capabilities. While the Phase 1/2 trial is not designed to statistically prove functional benefits, it aims to explore del-brax's clinical activity through various measures.

Avidity plans to accelerate the initiation of registrational cohorts based on these promising results, aiming to bring del-brax to the market more swiftly. The company's mission centers on leveraging their AOC platform to develop innovative RNA therapies for rare muscle diseases, including myotonic dystrophy type 1, Duchenne muscular dystrophy, and FSHD.