Avidity Biosciences’ Phase I/II trial of ribonucleic acid (RNA) therapy, del-zota, has increased dystrophin in patients with Duchenne muscular dystrophy (DMD).
Results from the company’s Explore44 trial (NCT05670730) found that targeted delivery of del-zota, an antibody oligonucleotide conjugate (AOC), saw an approximate increase of 40% in exon 44 skipping and a further 25% increase in dystrophin production.
Go deeper with GlobalData
DMD manifests when the exons within a patient’s dystrophin gene are destroyed, resulting in the gene’s inability to fulfil its role in keeping muscle cells intact, causing the primary symptoms of the muscle wasting disease.
The placebo-controlled, double-blind trial was able to restore dystrophin levels to 58% of the normal level. At the same time kinase levels, a biomarker associated with muscle degeneration, saw a mean reduction of 80% in patients treated with del-zota compared to baseline.
The findings were presented as part of the Muscular Dystrophy Association (MDA) 2025 meeting, taking place from 16 to 19 March in Dallas, Texas.
Sarah Boyce, president of Avidity, said: “We are particularly encouraged that these data demonstrate the consistent effects of del-zota across a variety of participants, including broad age range, genotypes and ambulatory and non-ambulatory participants. The early and durable effects observed with del-zota further strengthen our commitment to rapidly bring this potentially transformative therapy to people living with DMD442.”
The trial recruited 70 DMD patients amenable to exon 44 skipping at ten sites across the US. Patients received three doses of either 5mg del-zota or placebo every six weeks, or 10mg del-zota or placebo every eight weeks. In an earlier part of the study, the trial enrolled healthy volunteers to measure the safety of the therapy.
The announcement follows after the treatment was awarded orphan designation by the US Food and Drug Administration (FDA) and the European Medicines Agency (EMA).
Research by GlobalData’s Pharmaceutical Intelligence Centre estimates that del-zota is likely to bring in more than $12m globally for the company by the end of 2027, with that number predicted to rise to $33m by the end of 2030.
GlobalData is the parent company of Clinical Trials Arena.
Boyce added: “Based on our interactions with the FDA on accelerated approval, we believe dystrophin data from Explore44 combined with the safety data from our fully enrolled Explore44-OLE trial will support our planned BLA submission at the end of this year.”
It comes less than a day after Dyne Therapeutics announced that its Phase I/II trial examining its own DMD therapy DYNE-251, saw an “unprecedented and sustained” functional improvement in dystrophin expression. Elsewhere, PepGen is pausing the initiation of a new Phase II DMD trial as it awaits data from a separate, ongoing Phase II study.
