Doctors in the U.S. have used the gene-editing tool Crispr to treat a patient with a genetic disorder for the very first time.
But researchers caution that the procedure done as part of an ongoing trial for sickle cell disease is still experimental and that its use must be weighed against other treatment options.
According to the Centers for Disease Control and Prevention, a genetic defect in a patient’s hemoglobin, the blood protein that carries oxygen, causes cells to become “hard and sticky,” and take on an abnormal sickle shape that can cause blockages and lead to stroke and organ damage, among other complications.
With the Crispr technique, which involves using an enzyme to edit DNA at a precise location, scientists can alter a patient’s own blood cells to make them produce a hemoglobin variant normally only made by fetuses and babies for a short time after birth.
Following chemotherapy to wipe out any existing defective cells, the new cells can then be returned to the patient in the hopes that they’ll treat the disease.
The trial is being jointly conducted by Switzerland-based Crispr Therapeutics and Vertex Pharmaceuticals, which is headquartered in Boston, and will ultimately enroll up to 45 participants.
While other pharmaceutical companies are taking varying approaches to treat the disease, including different gene therapies, high prices remain an issue. The Crispr approach, researchers say, requires fewer cells and therefore could be more cost-effective.
Human trials of Crispr have ramped up this year. Doctors at the University of Pennsylvania tried the technique to treat cancer patients, while Massachusetts Eye and Ear Infirmary in Boston is currently recruiting for a study to edit cells in the retinas of patients with inherited blindness.
Many more cancer trials are underway in China, though the use of Crispr to edit the genomes of twin girls there last year caused international outcry and led the World Health Organization last week to call for any experiments that would lead to more gene-edited babies to be halted.