Avidity's Myotonic Dystrophy Drug Shows Promising Phase 1/2 Trial Results
Avidity Biosciences announced promising Phase 1/2 trial results for its myotonic dystrophy type 1 drug delpacibart etedesiran, showing 40% reduction in DMPK mRNA and functional improvements. The therapy has received multiple regulatory designations and is now in Phase 3 testing with data expected in late 2026. The company's stock has surged 128% over the past year despite reporting a net loss of approximately $550 million.
Avidity Biosciences announced that final results from its Phase 1/2 MARINA trial of delpacibart etedesiran (del-desiran) for myotonic dystrophy type 1 will be published in the February 19 issue of The New England Journal of Medicine. The investigational antibody oligonucleotide conjugate demonstrated approximately 40% mean reduction in DMPK mRNA across treated participants, addressing the underlying genetic cause of DM1, and showed improvements in multiple functional measures including hand function, muscle strength, mobility, and patient-reported outcomes.
The trial evaluated the therapy in 38 adults with DM1, a progressive neuromuscular disease with no approved disease-modifying therapies. Participants were randomized to receive either del-desiran at various doses or placebo. The treatment demonstrated an acceptable safety profile with most adverse events being mild or moderate, though two severe adverse events occurred in the higher dose cohorts, with one participant discontinuing the study.
Del-desiran is currently being evaluated in the global Phase 3 HARBOR study in people with DM1 aged 16 and older. The study completed enrollment in July 2025, with topline data expected in the second half of 2026. The drug has received Breakthrough Therapy, Orphan Drug and Fast Track designations from the FDA, as well as Orphan designation from European and Japanese regulators.
Avidity Biosciences has a market capitalization of nearly $11 billion. The company's shares have surged 128% over the past year and 64% in the last six months, trading near their 52-week high of $73.06. While Avidity holds more cash than debt on its balance sheet with a current ratio of 11.57, the company is not yet profitable, reporting a net loss of approximately $550 million in the last twelve months. Revenue grew 106% in the last twelve months, with analysts forecasting 87% sales growth this year, though the company is not expected to be profitable. The company is scheduled to report earnings on March 3rd.