The gene-editing tool has been used in a trial to enhance the blood cells of two patients with cancer, according to NPR.

The trial: The experimental research, under way at the University of Pennsylvania, involves genetically altering a person’s T cells so that they attack and destroy cancer. A university spokesman confirmed it has treated the first patients, one with sarcoma and one with multiple myeloma.

Slow start: Plans for the pioneering study were first reported in 2016, but it was slow to get started. Chinese hospitals, meanwhile, have launched a score of similar efforts. Carl June, the famed University of Pennsylvania cancer doctor, has compared the Chinese lead in employing CRISPR to a genetic Sputnik.

Ex vivo: It’s safer and easier to employ the CRISPR technique on cells removed from a patient’s body. That’s the case in the new cancer study, in which doctors collected blood from patients and then genetically engineered the immune cells present in it before returning the cells to the patients.

The edit: Researchers added one gene to make the T cells attack cancer, but they also used CRISPR to delete a different gene, called PD-1, which can act as a brake on the immune system’s defenses.

Pharmaceutical drugs that inhibit PD-1, known as immunotherapies, have been dramatically effective in treating a few cancers. Now the idea is to install the same capacity directly into the DNA of T cells.

CRISPR wave: The Pennsylvania cancer study is just one of many tests of medical treatments using CRISPR that are on the way. This year, for example, a patient in Europe became the first person to be treated with CRISPR for an inherited disease, beta thalassemia.

Funding: The Penn study is funded by the Parker Institute for Cancer Immunotherapy, an organization started by Napster cofounder and early Facebook investor Sean Parker, as well as by a startup firm, Tmunity. Parker has likened T cells to “little computers” that can be reprogrammed.

Sign up here for our daily newsletter The Download to get your dose of the latest must-read news from the world of emerging tech.