Previously, systemically delivered cEt gapmers showed high target gene reductions in mice with neuromuscular disorders.35, 36, 37 However, a Phase 1/2a study testing a DM1 Protein Kinase gene (DMPK) targeting cEt ASO in subjects with myotonic dystrophy was discontinued because the drug concentration in tissue was not high enough to elicit expected splicing changes (L.N. Mignon et al., 2016, Am. Acad. This evidence concerns the gene DMPK and myotonic dystrophy.