Avidity Biosciences, a biopharmaceutical company committed to delivering a new class of RNA therapeutics called Antibody Oligonucleotide Conjugates (AOCs), has been granted Fast Track designation by the U.S. Food and Drug Administration (FDA) for AOC 1020 for the treatment of facioscapulohumeral muscular dystrophy (FSHD).
FSHD is a serious, rare, hereditary muscle-weakening condition marked by life-long, progressive loss of muscle function that causes significant pain, fatigue, and disability. AOC 1020 is being studied in the Phase 1/2 FORTITUDE clinical trial in adults with FSHD and is the company’s second muscle-targeting small interfering RNA (siRNA) AOC in clinical development. Avidity plans to share data from a preliminary assessment of AOC 1020 in approximately half of study participants from the FORTITUDE trial in the first half of 2024.
Fast Track designation enables more frequent interactions with the FDA to expedite the development and review process for drugs intended to treat serious or life-threatening conditions and that demonstrate the potential to address unmet medical needs. Currently, there are no FDA-approved treatments for people living with FSHD.
“The FDA Fast Track designation for AOC 1020 reinforces the importance of finding an effective treatment to help people living with FSHD, a devastating and debilitating muscular dystrophy disorder with no treatment options,” said Steve Hughes, M.D., chief medical officer at Avidity. “AOC 1020 is designed to directly target the disease-causing gene, DUX4, to address the underlying cause of FSHD. We look forward to working collaboratively with the FDA to bring the first RNA therapy directly targeting DUX4 to patients as quickly as possible.”
Avidity’s proprietary AOCs are designed to combine the specificity of monoclonal antibodies (mAbs) with the precision of oligonucleotide therapies to target the root cause of diseases previously untreatable with RNA therapeutics. AOC 1020 consists of a proprietary mAb that binds to the transferrin receptor 1 (TfR1) conjugated with a siRNA targeting double homeobox 4 (DUX4) mRNA. The abnormal expression of DUX4 protein leads to changes in gene expression in muscle cells that are associated with the life-long, progressive loss of muscle function in patients with FSHD.
Avidity has three distinct rare disease programs in the clinic. In addition to AOC 1020, the company is also evaluating AOC 1001 in the Phase 1/2 MARINA and MARINA open-label extension (MARINA-OLE) clinical trials for the treatment of myotonic dystrophy type 1 (DM1) and AOC 1044 in the Phase 1/2 EXPLORE44 trial for the treatment of Duchenne muscular dystrophy (DMD) mutations amenable to exon 44 skipping (DMD44).