Novartis AG / Avidity Biosciences, Inc.

Myotonic Dystrophy Type 1 (DM1), FSHD, and Duchenne Muscular Dystrophy (DMD)

70K US cases/yr · $8.0B Combined US neuromuscular disease market (DMD, DM1, FSHD) rare-disease pricing potential · 3 Avidity late-stage AOC programs expected to launch before 2030

Disease Overview

Myotonic dystrophy type 1 (DM1) is an autosomal dominant multisystem disorder caused by CTG trinucleotide repeat expansion in the DMPK gene, characterized by progressive muscle weakness, myotonia, cardiac conduction abnormalities, cataracts, and cognitive involvement. Global pooled prevalence is approximately 9.27 per 100,000. A 2021 New York State newborn screening study identified DMPK CTG expansions at 4.76 per 10,000, suggesting a US diagnosed DM1 population of roughly 40,000. Facioscapulohumeral muscular dystrophy (FSHD) is the third most common muscular dystrophy after DMD and DM1, caused by abnormal DUX4 gene expression; NORD estimates US prevalence at 1 per 20,000 (~16,000 patients), presenting as progressive facial, shoulder-girdle, and upper-arm weakness. Duchenne muscular dystrophy (DMD) is an X-linked recessive dystrophinopathy affecting approximately 1 in 3,600 live male births; diagnosed US prevalence is 10,000-15,000 patients (CDC and NORD), predominantly males with progressive muscle degeneration, loss of ambulation by teens, and cardiorespiratory failure typically in the third decade. None of the three disorders has a disease-modifying therapy approved that directly addresses the underlying genetic mechanism across these targeted patient populations — creating a multi-indication rare-neuromuscular white space that Avidity's AOC platform targets via muscle-selective RNA delivery.

Competitive Landscape

Genetic neuromuscular space spans three MOA clusters where Avidity's AOCs compete. DMD — exon-skipping antisense oligos: Exondys 51 (eteplirsen), Vyondys 53 (golodirsen), Viltepso (viltolarsen), Amondys 45 (casimersen) — all Sarepta Therapeutics, limited dystrophin restoration. Gene therapy: Elevidys (delandistrogene moxeparvovec, Sarepta/Roche) — first AAV-based DMD gene therapy, approved 2023. Avidity's del-zota (AOC 1044) is an exon 44 skipping AOC with muscle-targeted delivery. DM1 — no approved disease-modifying therapy; competitors include PepGen (PGN-EDODM1, ASO), Dyne Therapeutics (DYNE-101, FORCE AOC platform), Vertex (VX-670). Avidity's del-desiran leads the clinical pack. FSHD — no approved therapy; competitors include Fulcrum Therapeutics (losmapimod, DUX4 modulator, Phase 3), Dyne (DYNE-302). Avidity's del-brax (AOC 1020) is the only AOC in late-stage FSHD development. Novartis' acquisition consolidates leadership in muscle-targeted RNA therapeutics against peer platforms from Dyne and Sarepta.