But the first versions of their experimental therapies require extracting the T cells from the patient, shipping them to a manufacturing plant where they can be altered, then sending them back and putting them back into the patient, something that will be logistically challenging and costly for thousands of patients. Cellectis’s therapy is meant to work for any patient with a particular type of leukemia.

But to make its treatment “universal,” Cellectis then takes another step using another new technology that is generating huge excitement — genome editing. This refers to using molecular scissors to make precise changes to DNA, just as one might edit a word in a document. The genome editing technique that has gotten the most attention is known as Crispr-Cas9, though Cellectis used an older approach known as Talens.

Man, that's a huge milestone considering the fears with gene editing directly in patients has been poor efficiency and accidentally making the target cells cancerous. I'd still be cautious on the cancer front, but this makes for an amazing breakthrough for the CART field!

Also TALENs may be "older", but they general have better target specificity than CRISPR, the downside being that the targeting is specified by the protein sequence (which is a bit harder to design / screen) rather than RNA (where designing is a matter of writing a sequence complementary to the target). It's pretty much expected that the first wave of gene therapies will all be TALENs / ZFNs.