In Vivo Assessment of dbDNA GNE^wt/bi-shRNA-GNE^M743T Lipoplex for GNE Myopathy: Improved Potency and Safety

GNE myopathy is an autosomal recessive disease, associated with skeletal muscle deterioration, which afflicts young adults. GNE plays a pivotal role in sialic acid production. Sialic acid acts as a buffer against reactive oxygen species generated during muscle contraction. Increased oxidative stress may relate to muscle atrophy involving patients with GNE myopathy. GNE^M743T is the most common mutation leading to GNE myopathy. In our previous work, we demonstrated that a bifunctional plasmid that expresses wild type (wt) GNE and knocks down the GNE^M743T mutant improves sialic acid production in vitro. Now, we expand evidence of in vivo activity of the bifunctional plasmid using a DOTAP-Cholesterol delivery vehicle and reduced toxic plasmid components using dbDNA conversion. We demonstrate that IV delivery of dbDNA lipoplex (LPX) in murine and rat models shows safety, increased DNA delivery, and improved RNA expression per LPX in skeletal muscle over non db plasmid at equal dose. Sialic acid protein expression was also shown increased in mouse muscle following IV treatment with dbDNA plasmid (pDNA) GNE^wt/bi-shRNA-GNE^M743T LPX. These results support further preclinical investigation to justify product IND development towards Phase 1 trial involving patients with GNE myopathy.