The US Food and Drug Administration (FDA) granted the experimental Duchenne muscular dystrophy (DMD) drug AOC 1044 Fast Track designation, according to a press release from Avidity Biosciences, the developers of the drug candidate.

This means that the company will be able to interact with the FDA more frequently, which will enable the faster development of the treatment.

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“It is very encouraging to receive FDA Fast Track designation as it further validates the potential of AOC 1044 to target the underlying cause of DMD44 and the importance of bringing people living with this devastating disease an effective treatment option,” Steve Hughes, MD, the chief medical officer of Avidity, said.

“We will continue to work closely with the FDA as we advance AOC 1044 and look forward to the anticipated data readout from the healthy volunteer portion of our phase 1/2 EXPLORE44 clinical trial later this year,” he added.

AOC 1044 is an exon-skipping drug that can benefit patients with DMD amenable to exon 44 skipping. It is a small interfering RNA that delivers a “molecular patch” to skeletal and heart muscles to skip exon 44, thereby restoring the reading frame of the DMD gene and enabling the production of a smaller but still functional dystrophin protein. 

EXPLORE44 evaluates the safety, pharmacokinetics, tolerability, and pharmacodynamics of AOC 1044 in healthy volunteers and patients with DMD amenable to exon 44 skipping. It is currently recruiting participants in San Antonio, Texas.

DMD is a rare and fatal disease caused by a mutation in the DMD gene that leads to no dystrophin protein being made. Dystrophin is essential for the health of muscle tissue, and in its absence, muscles degenerate and waste over time and are progressively replaced by scar tissue. Exon 44 skipping could benefit 6% of the DMD population. 


Avidity Biosciences granted FDA Fast Track designation for AOC 1044 for treatment of Duchenne muscular dystrophy mutations amenable to exon 44 skipping. New release. Avidity Biosciences. April 24, 2023. 

Study of AOC 1044 in healthy adult volunteers and participants with Duchenne muscular dystrophy (DMD) mutations amenable to exon 44 skipping (EXPLORE44). US National Library of Medicine. Updated April 4, 2023. Accessed April 25, 2023. 

Exon skipping is a potential treatment approach for correcting and restoring production of dystrophin. Cure Duchenne. Accessed Aprim 25, 2023.