FDA grants orphan drug designation to Duchenne muscular dystrophy treatment

The FDA has granted orphan drug designation to Avidity Biosciences Inc. for AOC 1044, its investigational monoclonal antibody to treat Duchenne muscular dystrophy in those with mutations amenable to exon 44 skipping.

In April, the regulatory body granted fast track designation for the novel therapeutic.

According to a press release from Avidity, the proprietary drug is designed to deliver phosphorodiamidate morpholino oligomers (PMOs) to skeletal muscle and heart tissue to specifically skip exon 44 of the dystrophin gene, which enables dystrophin production. Duchenne muscular dystrophy (DMD) results in progressive muscle degeneration and weakness due to alterations of a protein called dystrophin that protects muscle cells from injury during contraction.

The monoclonal antibody within AOC 1044 binds to the transferrin receptor 1 conjugated with a PMO targeting exon 44, per the release.

AOC 1044 will be examined in the EXPLORE44 trial, a randomized, placebo-controlled, double-blind, phase 1/2 study to evaluate AOC 1044 in approximately 40 healthy volunteers, as well as 24 individuals with DMD mutations amenable to exon 44 skipping (DMD44). EXPLORE44 was conceived to evaluate safety, tolerability, pharmacokinetics and pharmacodynamic effects of single and multiple IV ascending doses of AOC 1044.

"There are currently no treatment options that target the underlying cause of DMD44,” Steve Hughes, MD, chief medical officer at Avidity, stated in the release. "We look forward to advancing AOC 1044 in clinical development and bringing this very important treatment to patients as quickly and safely as possible."

Avidity further revealed plans to release results from the healthy volunteer portion of the study during the fourth quarter of 2023 and announced it is enrolling participants living with DMD44.