Avidity Biosciences, Inc. (NASDAQ:RNA) on Wednesday shared new data from participants treated continuously with del-zota for one year in the EXPLORE44 and EXPLORE44-OLE trials for Duchenne muscular dystrophy (DMD).
DMD is a rare genetic condition characterized by progressive muscle damage and weakness beginning at a very young age due to the absence of dystrophin protein from birth.
These data demonstrated reversal of disease progression and improvement compared to baseline and natural history across multiple functional measures.
Del-zota is designed to deliver phosphorodiamidate morpholino oligomers (PMOs) to skeletal muscle and heart tissue to specifically skip exon 44 of the dystrophin mRNA and enable production of functional, near-full-length dystrophin.
Near-full-length dystrophin retains key functional domains and may offer improved muscle protection for people living with DMD44.
Data Highlights:
Trial participants treated with del-zota demonstrated statistically significant increases of approximately 25% of normal in dystrophin production and restored total dystrophin up to 58% of normal.
Creatine kinase (CK) levels rapidly reduced by greater than 80% compared to baseline and were sustained at near normal levels throughout the duration of evaluation, with participants followed for up to 16 months.
Additionally, 50% of participants had CK levels within the normal range at one year of treatment.
A total of 17 participants (12 ambulatory and five non-ambulatory) who began on the del-zota-treated arm of EXPLORE44 and continued into the EXPLORE44-OLE have been followed for approximately one year.
Functional data from pooled dosing cohorts for del-zota-treated participants, compared to DMD44 natural history (PRO-DMD-01), demonstrated improvement:
4-Stair Climb (4SC) improved from baseline by 2.1 seconds. In contrast, the natural history group declined from baseline by 2.7 seconds.
10-Meter Walk/Run Test (10mWRT) improved from baseline by 0.7 seconds vs. declined from baseline by 1.5 seconds
Time to Rise from Floor (TTR) improved from baseline by 3.2 seconds compared to a decline from baseline by 1.6 seconds in natural history.
North Star Ambulatory Assessment (NSAA) remained stable. The natural history group declined from baseline by 2.4 points.
Performance of Upper Limb (PUL2) improved from baseline by 1.5 points. In contrast, the natural history group declined from baseline by 0.7 points. Similar PUL improvements were seen in both ambulatory and non-ambulatory participants.
Safety was assessed in all participants in the EXPLORE44-OLE trial, and del-zota continued to demonstrate a favorable long-term safety and tolerability profile.
Avidity remains on track to submit a marketing application to the U.S. Food and Drug Administration at the end of 2025.
Price Action: RNA stock is up 0.58% at $46.89 at the last check on Wednesday.
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