DMD CLINICAL THERAPIES II

Wave life sciences is developing investigational stereopure exon-skipping oligonucleotides as potential disease-modifying therapies for the treatment of patients with Duchenne muscular dystrophy (DMD). Wave's proprietary technologies enable the production of stereopure oligonucleotides in which stereochemistry at each phosphorothioate position is precisely controlled. WVE-210201, which targets exon 51 in the dystrophin (DMD) gene, is currently being studied in a Phase 1 clinical trial in DMD patients amenable to exon 51 skipping. Wave has also designed stereopure oligonucleotides to target exon 53 in the DMD gene. In vitro experiments were conducted in DMD patient-derived myoblasts with Δ45-52 mutation. Cells were treated with oligonucleotides under gymnotic (free uptake) conditions and then analyzed for exon skipping efficiency by Taqman assay and protein quantification by western blot. Stereopure oligonucleotides showed dose-dependent exon 53 skipping efficiency and protein restoration when normalized to wild-type myoblasts. These results were consistent across cell culture conditions and were further confirmed in a second DMD patient myoblast cell line (Δ52). Stereopure oligonucleotides led to negligible activation of the TLR9 innate immune receptor in a reporter assay, and negligible activation of cytokines when incubated with healthy human peripheral blood mononuclear cells (PBMCs) ex vivo and in vivo in mice. A single 30 mg/kg intravenous dose of oligonucleotide to a dystrophin deficient mouse model (mdx-23) rapidly penetrated muscles (quadriceps, gastrocnemius, heart and diaphragm) 24 hours after administration, as detected by both viewRNA IHC assay and hybridization ELISA. These studies support further development of a stereopure oligonucleotide as a potential treatment for patients with DMD amenable to exon 53 skipping.