Biotech companies have been telling us for a while now that CRISPR, the gene-editing technology, can be shaped into a radically precise form of gene therapy. Now one of them, CRISPR Therapeutics, says it’s ready to test the idea on people.

The startup  said Thursday it has just asked regulators in Europe to allow it to try to cure the disease beta thalassemia with a genetic correction to people’s blood cells. The study could begin next year.

The potential of CRISPR to supercharge gene therapy was obvious by 2013, when the technology was first shown to be able to surgically cut and paste genetic code in a living human cell. Soon after, what could be called the “big three” CRISPR biotechs had been founded and funded, and all staged IPOs. In addition to CRISPR Therapeutics, they are Editas Medicine and Intellia Therapeutics. All are based within a few blocks of MIT in Cambridge, Massachusetts.

When these companies started, much was left to investors’ imagination. But they’ve moved quickly to try to get CRISPR out of the lab and into clinical trials, a key milestone for any company proposing to invent a new type of medicine.

Each of the three companies is moving toward that goal, but not without difficulty. Editas, once the front runner, which thought it would be first to do gene editing in a living person, decided earlier this year it would have to postpone the start of its study of an eye treatment until sometime during 2018. Intellia, which rounds out the biotech trio, is still collecting data from monkeys—critical evidence for how its own CRISPR drugs will perform.