Chinese researchers used the tool to give a patient blood cells that were altered to resist the AIDS-causing virus, the Associated Press reported.
The study was published Wednesday in the New England Journal of Medicine.
It's the first published report of trying to use CRISPR to treat a disease in an adult, according to the AP.
Even though CRISPR did not cure the patient's HIV infection, the gene-editing tool appears precise and safe in the patient and appears to hold promise, said Dr. Carl June, a University of Pennsylvania genetics expert who wrote an accompanying commentary in the journal.
"That's really good for the field," June told the AP.