More than 50 experimental studies are underway that use gene editing in human volunteers to treat everything from cancer to HIV and blood diseases. Most of these investigations, about 40 of them, involve CRISPR (Clustered Regularly Interspaced Short Palindromic Repeats), the most versatile of the gene-editing methods, which was developed only 10 years ago. CRISPR is a revelation to scientists because of how it can snip the genome at specific locations. A cutting protein is paired with a short gene sequence that acts like GPS, zipping to a predetermined spot in an individual's chromosomes. According to an article in the May/June 2023 issue of the journal MIT Technology Review, one of the first patients treated using a CRISPR procedure, in 2019, was Victoria Gray. At the Third International Summit on Human Genome Editing, held in London in March 2023, she described to the audience how her earlier battle with sickle-cell disease resulted in episodes that left her hospitalized for months at a time.
Then she underwent a treatment that involved editing the genes in cells from her bone marrow. Within minutes of receiving a transfusion of edited cells, she shed tears of joy. The company developing her treatment, Vertex Pharmaceuticals, has treated more than 75 patients in its studies of sickle-cell and a related disease, beta thalassemia. The therapy could be approved for sale in the U.S. within a year. It is widely expected to be the first treatment using CRISPR to go on sale, but a price has not been announced. Other biotech companies, such as Intellia, Beam Therapeutics, and Editas Medicine, are hoping they can use this technology to develop successful treatments. Many are running trials. A challenge facing all these efforts remains placing CRISPR where it needs to go in the body, which is not easy to accomplish. In Gray's case, doctors removed bone marrow cells and edited them in the laboratory. Before they were added back to her body, however, she underwent punishing chemotherapy to kill off her remaining bone marrow in order to make room for the new cells. Meanwhile, thousands of other inherited diseases that could be treated with CRISPR are being ignored because most of them are too rare to be a viable commercial opportunity.