People with a rare form of inherited blindness are being enrolled for the world’s first in vivo human study of a CRISPR-based therapy, the Associated Press reported yesterday (July 25). The experimental treatment, developed by Massachusetts-based genome-editing company Editas Medicine and Ireland-based pharmaceutical firm Allergan, removes a deleterious mutation from cells in patients’ retinas, and will be tested in 18 adults and children later this year.
“Today marks an important day for the inherited retinal disease community,” Ben Yerxa, CEO of nonprofit Foundation Fighting Blindness, says in a press statement. “We are very excited to have another potentially life changing medicine enter the clinic and join Allergan and Editas in celebrating this milestone.”
The therapy is designed to treat people with a particular form of a disease known as Leber congenital amaurosis that is caused by a point mutation in a gene called CEP290. This particular mutation leads to abnormal splicing and dysfunctional production of the CEP290 protein, which plays an important role in the photoreceptors in the eye. Once injected under the retina, the therapy should cut out the mutation in the gene and restore normal splicing.
The trial differs from previous attempts to use CRISPR for therapeutic purposes, which have either been ex vivo (using cells extracted from patients and then replaced post-editing), or, controversially, in embryonic cells. Because the treatment is only applied locally to somatic cells, the changes it makes will not be heritable.