FDA Considers First CRISPR Gene Editing Treatment That May Cure Sickle Cell

The U.S. Food and Drug Administration is reviewing a cutting-edge therapy called exa-cel that could potentially cure people of sickle cell disease, a painful and deadly disease with no universally successful treatment. 'If approved, exa-cel, made by Boston-based Vertex Pharmaceuticals and the Swiss company CRISPR Therapeutics, would be the first FDA-approved treatment that uses genetic modification called CRISPR,' reports CNN. From the report: CRISPR, or clustered regularly interspaced short palindromic repeats, is a technology researchers use to selectively modify DNA, the carrier of genetic information that the body uses to function and develop. The new exa-cel treatment under FDA consideration can use the patient's own stem cells. Doctors would alter them with CRISPR to fix the genetic problems that cause sickle cell, and then the altered stem cells are given back to the patient in a one-time infusion.

In company studies, the treatment was considered safe, and it had a 'highly positive benefit-risk for patients with severe sickle cell disease,' Dr. Stephanie Krogmeier, vice president for global regulatory affairs with Vertex Pharmaceuticals Incorporated, told the panel. Thirty-nine of the 40 people tested with the treatment did not have a single vaso-occlusive crisis, which means the misshapen red blood cells block normal circulation and can cause moderate to severe pain. It's the top reason patients with sickle cell go to the emergency room or are hospitalized. Before the treatment, patients experienced about four of these painful crises a year, resulting in about two weeks in the hospital.

The FDA sought the independent panel's advice, in part, because this would be the first time the FDA would approve a treatment that uses CRISPR technology, but Dr. Fyodor Urnov, a professor in the Department of Molecular and Cell Biology at the University of California, Berkeley, reminded the committee CRISPR has been around for 30 years and, in that time, scientists have learned a lot about how to use it safely. 'The technology is, in fact, ready for primetime,' Urnov said. With this kind of genetic editing, scientists could inadvertently make a change to a patient's DNA that is off-target, and the therapy could harm the patient. The FDA is expected to make an approval decision by December 8.

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