The CRISPR gene-editing tool has been used inside the human body for the first time. In a new clinical trial, scientists at the Oregon Health and Science University (OHSU) are testing the technique as a treatment for a genetic mutation that causes blindness.
Ever since it was developed in 2012, CRISPR has shown promise as a potential new way to treat a range of genetic conditions. The tool allows doctors to snip out problematic sections of DNA, such as those that cause disease, and gives the option to replace them with something beneficial.
The new trial, being conducted at OHSU and sponsored by private companies Allergan plc and Editas Medicine, targets a form of Leber congenital amaurosis (LCA). This rare condition is triggered by a genetic mutation that affects the retina, causing patients to either be born blind or lose their sight within the first few years of life.
For this particular type of LCA, the mutation occurs on a gene called CEP290, so this was the target for the trial. The researchers inject the CRISPR-loaded medicine directly into photoreceptor cells behind the retina, where it goes to work removing the faulty gene.
CRISPR has been tested in humans before, but in those cases cells were removed from the patient, edited and then returned to the body. This new clinical trial marks the first time CRISPR has been put to work in vivo – directly inside the human body.
“Being able to edit genes inside the human body is incredibly profound,” says Mark Pennesi, OHSU’s lead scientist in the trial. “Beyond potentially offering treatment for a previously untreatable form of blindness, in vivo gene editing could also enable treatments for a much wider range of diseases.”
The treatment is designed to be permanent for the patients, but won’t be passed down to any children they may have in future. This is an important distinction, as one of the major risks of gene therapy is that if something goes wrong in that situation it may alter the human gene pool for generations. This concern was realized in 2018, when secretive experimentation led to the birth of the world’s first gene-edited babies.
So far, the new CRISPR treatment has only been conducted on one patient, and it’s too early for the results to have been recorded. A total of around 18 participants are expected to take part, as the scientists test how well the treatment works, how safe it is and how well the body tolerates it.
Sources: OHSU, Editas Medicine, via Associated Press