According to a recent announcement, the FDA has granted rare pediatric disease designation to AOC 1044, Avidity Biosciences’ investigational therapy for the treatment of Duchenne muscular dystrophy (DMD) in patients living with mutations amenable to exon 44 skipping (DMD44).1 The company noted that it is expected to share 5 mg/kg cohort data from the phase 1/2 EXPLORE44 trial (NCT05670730) assessing the therapy in patients with DMD44 in the second half of 2024.2
EXPLORE44 is a randomized, placebo-controlled, double-blind trial comprised of healthy volunteers and patients with DMD44. In December 2023, the company announced topline data from the trial that showed AOC 1044 was safe among healthy volunteers and delivered 50-times greater concentrations of phosphorodiamidate morpholino oligomers (PMO) in skeletal muscle following administration. AOC 1044, a proprietary monoclonal antibody, binds the transferrin receptor 1 conjugated with a PMO targeting exon 44.
"We are pleased that the FDA has granted rare pediatric disease designation to AOC 1044, adding to the orphan drug and fast track designations already granted. The effects of DMD44 are devastating, with symptoms often starting in childhood. These designations by the FDA underscore the urgent need for innovative treatments and validate the potential of AOC 1044 to address the unmet need of patients living with Duchenne muscular dystrophy," Steve Hughes, MD, chief medical officer at Avidity, said in a statement.1
Top Clinical Takeaways
- AOC 1044 has received rare pediatric disease, orphan drug, and fast track designations from the FDA for treating Duchenne muscular dystrophy (DMD).
- Early trial results indicate AOC 1044 significantly increased PMO concentrations in skeletal muscle and is well tolerated with mild to moderate adverse events.
- The promising results and FDA designations underscore the potential of AOC 1044 to meet the urgent need for new treatments for patients with DMD.
READ MORE: FDA Grants Rare Pediatric Disease Designation to DMD Gene Therapy Candidate SGT-003
In a cohort of approximately 40 healthy volunteers, AOC 1044 delivered unprecedented, dose-dependent increases in PMO concentrations in skeletal muscle following a single dose of 5 mg/kg or 10 mg/kg, which were significantly greater when compared with a single dose of peptide conjugated PMOs. At day 29, patients treated with a single dose of 10 mg AOC 1044 demonstrated statistically significant exon 44 skipping of up to 1.5% in comparison with placebo. The investigational therapy was well tolerated in healthy volunteers, with all treatment-emergent adverse events (TEAEs) considered mild to moderate. There were no reports of symptomatic hemoglobin changes, no hypomagnesemia, and no renal events.
"We recently shared healthy volunteer data of AOC 1044 from our phase 1/2 EXPLORE44 trial demonstrating unprecedented delivery of therapeutic oligonucleotide in skeletal muscle and consistent exon skipping in healthy volunteers, and we look forward to sharing data from that study in patients living with DMD44 later this year. We remain steadfast in our commitment to advancing science and improving the lives of people and their families affected by this devastating condition,” Hughes said in a statement.1
In August 2023, the FDA granted orphan drug designation to AOC 1044 for patients with DMD44.3 Following this news, Hughes sat down with NeurologyLive® to discuss how the EXPLORE44 trial addresses the challenges associated with rare disease treatments, specifically with DMD. He also talked about the significance of FDA orphan drug designation and fast track status for the development of treatments for rare diseases, in particular with AOC 1044. In addition, Hughes elaborated on the 2 phases of EXPLORE44 and how they both will contribute to its potential success.