Actually, it's the other way around. The treatment described is an adaption of CAR-T (Chimeric Antigen Receptor T-cell) therapy, which was approved for use in the United States in 2017, to the patient's specific form of leukemia. It's a challenging adaptation because the cancer cells being targeted are the same type of T-cells that are used in CAR-T therapy, thus requiring the use of donor T-cells, and a number of modifications that are unnecessary when CAR-T is used for other cancers. Base editing makes that easier than earlier forms of CRISPR. But base editing isn't the therapy here, CAR-T is, and while CAR-T is certainly relatively, this patient is not the first to receive, just the first with her particular leukiemia.
No, the parent comment is totally fine. The technique is indeed new and yes will be applied in the treatment of other diseases in the future. Don’t know why you went to open with a contrarian tone.
My point was simply that this is an adaptation of an existing therapeutic tool (CAR-T) to a particular cancer, not something completely novel. It's a leaf on a tree of therapies, not a new tree per se.