First gene-editing treatment injected into the blood reduces toxic protein for up to 1 year

^{Cas9 from CRISPR from NIH, CC BY-NC 2.0}

The first team to disable a disease gene directly in a person through an infusion of the genome editor CRISPR reported yesterday that levels of the toxic protein made by the gene dropped as much as 93% for up to 1 year. The researchers hope the long-term reduction means patients in the clinical trial will soon show clear improvement in their nerve symptoms and that these benefits will persist for an extended period.

“It is quite remarkable that this first [intravenous] CRISPR-based gene-editing effort has been so successful,” says gene therapy researcher Terence Flotte of the University of Massachusetts Medical School, who was not involved with the study. “This demonstrates great potential for the power of this platform clinically.”

People who have inherited a gene mutation responsible for a condition known as transthyretin (TTR) amyloidosis can develop nerve pain, numbness, and heart failure as adults. The genetic defect results in buildup in nerves and organs of a misfolded version of TTR, a protein made by the liver. Last year, the companies...