FDA Grants Fast Track Designation for Avidity’s DMD Therapy

Rare Daily Staff

The U.S. Food and Drug Administration has granted Fast Track designation to Avidity Biosciences’ AOC 1044 for the treatment of the rare neuromuscular condition Duchenne muscular dystrophy in people with mutations amenable to exon 44 skipping.

Duchenne muscular dystrophy (DMD) is a genetic condition that causes a lack of functional dystrophin leading to stress and tears of muscle cell membranes and resulting in muscle cell death and the progressive loss of muscle function. The dystrophin protein maintains the integrity of muscle fibers and acts as a shock absorber through its role as the foundation of a group of proteins that connects the inner and outer elements of muscle cells. People living with DMD suffer from progressive muscle weakness that typically starts at a very young age. Over time, people with Duchenne will develop problems walking and breathing, and eventually, the heart and respiratory muscles will stop working. Those living with the condition often require special aid and assistance throughout their lives and have significantly shortened life expectancy. While there are treatments approved to treat people with DMD, there remains a very high unmet need. DMD is a monogenic, X-linked, recessive disease that primarily affects males, with one in 3,500 to 5,000 boys born worldwide having Duchenne.

AOC 1044 is an antibody oligonucleotide conjugate designed to deliver phosphorodiamidate morpholino oligomers (PMOs) to skeletal muscle and heart tissue to specifically skip exon 44 of the dystrophin gene to enable dystrophin production in people living with Duchenne muscular dystrophy, with mutations amenable to exon 44 skipping (DMD44). AOC 1044 consists of a proprietary monoclonal antibody that binds to the transferrin receptor 1 (TfR1) conjugated with a PMO targeting exon 44. In a preclinical model of DMD, a murine active AOC produced durable exon skipping and functional dystrophin protein in skeletal muscle and heart tissue following a single intravenous dose. AOC 1044 is currently in phase 1/2 development as part of the EXPLORE44 trial for the treatment of DMD mutations amenable to exon 44 skipping.

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 therapies approved targeting exon 44.

“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,” said Steve Hughes, chief medical officer at Avidity. “This recognition also means that now all three of our clinical-stage programs have Fast Track status, further reinforcing our efforts to make a profound difference in people’s lives.”