Super-precise CRISPR tool enters US clinical trials for the first time

A high-precision successor to CRISPR genome editing has reached a milestone: the technique, called base editing, has made its US debut in a clinical trial. The trial tests more complex genome edits than those performed in humans so far.

Trial organizers announced on 5 September that the first participant had been treated using immune cells with four base-edited genes, equipping the cells to better target and destroy tumours. The hope is that the approach can tame trial participants’ difficult-to-treat form of leukaemia and serve as a gateway to more complex edits in the future.

“There are things still to be built into these cells to make them easier to use and persist longer,” says Waseem Qasim, a paediatric immunologist at the University College London Great Ormond Street Institute of Child Health. “And with so many groups working on it, things will get incrementally better.”

It’s been a strikingly quick evolution from the first reports of base editing in 2016 to clinical trials, but the CRISPR field has never been one to dawdle. And while researchers develop ever more...