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Exonics Therapeutics Announces Publication of Research Demonstrating Gene Repair Technology Corrected Dystrophin Expression in Mouse Model of Duchenne Muscular Dystrophy

SingleCut CRISPR efficiently restored up to 90% of dystrophin expression in skeletal and heart muscles

Study published in the journal Science Translational Medicine

CAMBRIDGE, Mass. – November 29, 2017 Exonics Therapeutics, Inc., a biotechnology company focused on developing SingleCut CRISPR technology to repair mutations causing Duchenne muscular dystrophy and other neuromuscular diseases, today announced the publication of a preclinical study demonstrating the Company’s SingleCut CRISPR technology efficiently corrected in vivo dystrophin expression in a mouse model of Duchenne.

Duchenne is a devastating muscle disease in children for which there is no cure. It is caused by mutations of the dystrophin protein gene responsible for stabilizing and protecting muscle fibers, which results in progressive muscle weakness and leads to life-threatening and ultimately fatal medical issues. Data suggest that deletions of exon 50 of the dystrophin gene are among the most common single exon deletions causing Duchenne, and the gene can be repaired by editing exon 51.

Researchers generated a new humanized mouse model of Duchenne that lacks exon 50. They found that one systemic delivery of adeno-associated virus (AAV) encoding gene-editing enzyme CRISPR/Cas9 directed by highly specific single guide-strand RNA was able to restore the expression of dystrophin in mice to up to 90 percent of normal levels in skeletal and heart muscles. Improved muscle function was also observed in the Duchenne mouse model, compared to control, and no off-target effects were detected in the six potential sites.

“This study indicates the potential of Exonics’ SingleCut CRISPR approach to enhance the efficiency of gene correction and restoration of dystrophin expression in skeletal and cardiac cell types after a single systemic administration, with a single cut in a precise location,” said Leonela Amoasii, Ph.D., lead author of the research and director of gene editing at Exonics. “By using only a single cut to the DNA, the SingleCut CRISPR approach requires minimal modification of the genome, can be adapted to the editing of other exons, and reduces the likelihood of off-target effects. Further, the newly developed Duchenne exon 50 mouse model will be invaluable as we conduct further studies exploring the most predominant Duchenne mutation.”

“Exonics is committed to generating a robust foundation of scientific data that supports the development of a safe and efficacious one-time treatment leveraging SingleCut CRISPR to potentially provide lifelong benefit to Duchenne patients,” said John Ripple, chief executive officer of Exonics. “This research deepens our understanding of how our SingleCut CRISPR technology can be used to induce normal expression of dystrophin in genes with exon 50 deletion, and forms the cornerstone of the continued development of our technology to address additional Duchenne mutations in the future.”

The research article, titled, “Single-cut genome editing restores dystrophin expression in a new mouse model of muscular dystrophy,” was published online in the journal Science Translational Medicine.

About Exonics Therapeutics

Exonics Therapeutics has developed SingleCut CRISPR, a gene repair technology that has the potential to effectively halt the progression of certain genetic neuromuscular diseases. In multiple Duchenne muscular dystrophy preclinical models, Exonics has used SingleCut CRISPR to genetically repair and restore dystrophin, the key protein missing in children with Duchenne. Exonics is initially focused on correcting mutations that cause Duchenne in order to develop a therapy to treat many children with the devastating disease, for which there is no cure. Exonics’ technology is licensed from UT Southwestern Medical Center and is based on the research of Eric Olson, Ph.D., Exonics’ founder and chief science advisor. Exonics is located in Cambridge, Mass. For more information, please visit


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