Two children with leukemia are slowly starting to recover after undergoing a new and unique treatment method. The plan was to kill their cancers using a special gene-editing method, and surprisingly, it worked.

A team of experts from the Great Ormond Street Hospital conducted the treatment to the first girl, Layla. Back in November, the team could not give conclusive results if the girl was indeed cured of leukemia, but had positive results (without any signs of the disease) 18 months later, as per New Scientist.

This marks yet another surprising take on how effective gene editing can become to treat conditions.

But what exactly is the treatment? Dubbed as CAR-T cell therapy, the method targets specific cancer cells through the addition of a gene to immune cells. The said gene is added via a virus, New Scientist reports.

The "virus" carries a part of the patient's RNA with a specific pattern that it should "cut" that corresponds to a pre-programmed code. This allows it to instantly kill without damage certain genes with cancer properties.

Despite the promising results, the CAR-T cell therapy is not full-proof. The method is expensive and not readily available because patients need to be treated using their own modified immune cells. This eradicates the option of using off-the-shelf cells as the body will treat them as foreign objects that are viable for an attack.

However, there's still good news. Cellectis, a Paris-based company, has developed a gene-editing tool that allows the use of immune cells from an outsider without the host body attacking them.

These new gene-editing methods open doors to new ways of improving immune cancer therapies. Scientists have been starting to use these methods, with two cancer trials using CRISPR-edited cells undergoing in China and the U.S.