A new experimental therapy called del-zota has shown reversal of muscle decline in people living with Duchenne muscular dystrophy (DMD), according to a press release published recently by its maker, Avidity Biosciences.
An investigational RNA-based therapy, del-zota is designed to enable dystrophin production in people with mutations that are amenable to skipping exon 44 of the DMD gene. According to the new results from Avidity Biosciences’ EXPLORE44 and EXPLORE44-OLE trials, del-zota improved strength and function across multiple key measures after one year of treatment.
“For the first time, we have data showing that sustained muscle protection leads to meaningful improvements across multiple key functional measures in DMD,” said Sarah Boyce, President and Chief Executive Officer of Avidity Biosciences.
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The trial included 17 participants with mutations amenable to exon 44 skipping. After receiving del-zota, patients showed measurable improvement compared with expected decline based on natural history studies.
Time to rise from the floor improved by 3.2 seconds, while untreated peers worsened by 1.6 seconds. In the four-stair climb, participants improved by 2.1 seconds compared with a 2.7-second decline in the natural history group. Arm strength and function also improved by 1.5 points on a standard scale, while untreated peers lost ability.
In addition to functional gains, del-zota reduced blood levels of creatine kinase, an enzyme linked with muscle damage, by more than 80% and kept them near normal through 16 months of follow-up. Production of dystrophin protein increased by about 25% of normal, with some patients reaching as high as 58%. These results suggest that the therapy not only slows muscle loss but also restores part of the missing protein.
Safety findings were encouraging, with most side effects described as mild or moderate. Common issues included respiratory symptoms, diarrhea, falls, back pain and headaches. Only one participant left the study because of a hypersensitivity reaction.
Avidity Biosciences plans to seek accelerated approval from the U.S. Food and Drug Administration by the end of 2025. If successful, del-zota could provide a new option for families facing DMD, where treatment choices remain limited and the need is urgent.
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