Researchers from the Stanford University School of Medicine have reportedly used CRISPR, a gene-editing tool, to repair the gene that causes sickle cell disease. The team is planning the 1st human clinical trial using this technique to correct cells with sickle cell disease, according to Reuters.
“What we’ve finally shown is that we can do it. It’s not just on the chalkboard,” senior author Dr. Matthew Porteus told the news outlet. “We think we have a complete data set to present to the FDA to say we’ve done all pre-clinical experiments to show this is ready for a clinical trial.”
CRISPR-Cas9 behaves as a type of “molecular scissors” that can trim away selective parts of the genome and replace it with new pieces of DNA.
Previous work done at the University of California Berkeley showed CRISPR can remove the diseased gene for sickle cell and deliver a new stretch of DNA to correct the genetic mutation in stem cells. Nearly 25% of blood-forming cells were repaired in their study.
The team at Stanford used CRISPR to remove the same gene, but then used a harmless virus to introduce the repair mechanism into cells.
Researchers tested the tool in cells from 4 patients with sickle cell disease and observed that they could repair the mutation in 30% to 50% of diseased cells. The cells were still thriving 16 weeks after they were injected into young mice.
Porteus told Reuters that he was encouraged by the results, as previous work has shown that correcting mutations in 10% of cells is enough to cure the disease.
Stanford is preparing for human trials in its laboratories, even building a cell manufacturing plant. “We hope to develop the entire process here at Stanford,” Porteus said.
The clinical trial will involve chemotherapy targeted at the patient’s blood system, but not their immune system. The team will inject the patient’s own corrected stem cells, in the hopes that the repaired cells will engraft into the bone marrow and produce blood cells, free of sickle cell disease.
Porteus told Reuters that the team plans to make its 1st submission to the FDA over the next few months and will treat the 1st patient in 2008. Porteus has equity interest in CRISPR Therapeutics in Cambridge, Mass., but he told the news outlet that the team’s sickle cell work has been independent of it.
CRISPR has made headlines as a battle over patent control has waged between researchers at the University of California and the Broad Institute. Oral arguments in the case are expected on Dec. 6 in Alexandria, Virginia at the U.S. Patent and Trademark Office.