First CRISPR therapy dosed

An adult with congenital blindness is the first person to receive an in vivo CRISPR-based therapy, according to the sponsors of the clinical trial: Editas Medicine and Allergan. The trial is testing whether EDIT-101 (also known as AGN-151587) can remove a point mutation in the CEP290 gene , which causes type 10 of the retinal degenerative disease Leber congenital amaurosis (LCA). The IVS26 mutation leads to a functional loss in the CEP290 protein, which causes defects in retinal photoreceptors and severe vision loss. To correct the IVS26 mutation, EDIT-101 uses a construct containing the adenovirus vector AAV5 with two guide RNAs to identify the location of the IVS26, combined with DNA encoding the Cas9 enzyme under a promoter specific to photoreceptor cells. Another gene therapy for LCA is Luxturna (voretigene neparvovec-rzyl) from Spark Therapeutics, now owned by Roche. Both Editas and Spark use an AAV vector, but whereas Editas’s genome editing corrects the mutation, Spark’s agent introduces a correct copy of the affected gene. Luxturna is approved for treating specifically the form caused by mutation of the retinal pigment epithelial 65 ( RPE65 ) gene.