Avidity Biosciences Reports Positive 1-Year Data on Del-Zota Treatment.

Avidity Biosciences reported positive one-year data from its EXPLORE44 trial, showing unprecedented improvement in functional measures such as Time to Rise from Floor, 4-Stair Climb, and 10-Meter Walk/Run Test. Creatine kinase levels also decreased to near normal levels and dystrophin production increased by 25%. The company remains on track to submit a Biologics License Application for accelerated approval at year-end 2025.

Avidity Biosciences, Inc. (Nasdaq: RNA) has announced positive one-year data from its EXPLORE44 trial, demonstrating unprecedented improvements in functional measures for participants with Duchenne muscular dystrophy (DMD). The trial, which assessed the safety, tolerability, and efficacy of del-zota, an RNA therapeutic designed to skip exon 44 of the dystrophin gene, showed significant progress in multiple functional measures, including Time to Rise from Floor (TTR), 4-Stair Climb (4SC), Performance of Upper Limb (PUL), and 10-Meter Walk/Run Test (10mWRT).

The data, presented at the company's investor and analyst webcast event on September 10, 2025, revealed a 25% increase in normal dystrophin production and a rapid reduction in creatine kinase (CK) levels to near normal levels, sustained over 16 months of follow-up. These improvements were accompanied by a statistically significant reduction in functional decline compared to the natural history of the disease, as measured by the 4SC, 10mWRT, and TTR tests.

The trial, which included both ambulatory and non-ambulatory participants, showed that del-zota treatment led to improvements in functional measures across the board. For example, participants treated with del-zota improved their 4SC performance by 2.1 seconds compared to baseline, while the natural history group declined by 2.7 seconds. Similarly, the 10mWRT improved by 0.7 seconds in the treated group compared to a decline of 1.5 seconds in the natural history group.

Safety assessments in the EXPLORE44-OLE trial, which followed the Phase 1/2 EXPLORE44 trial, showed a favorable long-term safety and tolerability profile. Most treatment emergent adverse events (TEAEs) were mild or moderate, with the most common being upper respiratory tract symptoms, diarrhea, fall, back pain, and headache.

Avidity Biosciences remains on track to submit a Biologics License Application (BLA) to the U.S. Food and Drug Administration (FDA) by year-end 2025 for accelerated approval, following the completion of a confirmatory study to support full global approval. The company is also preparing for an upcoming scientific congress to present additional data from the EXPLORE44 program.

This progress highlights Avidity Biosciences' commitment to delivering a new class of RNA therapeutics called Antibody Oligonucleotide Conjugates (AOCs™) and underscores the potential of del-zota as a transformative treatment for DMD. As the company continues to advance its development program, investors and financial professionals will closely monitor the ongoing clinical trials and regulatory submissions for further updates.