An anonymous reader shares an NPR report: A new kind of cancer treatment that uses genetically engineered cells from a patient's immune system to attack their cancer easily cleared a crucial hurdle Wednesday. A Food and Drug Administration advisory committee unanimously recommended that the agency approve this "living drug" approach for children and young adults who are fighting a common form of leukemia. The agency doesn't have to follow the committee's recommendation but usually does. The treatment takes cells from a patient's body, modifies the genes, and then reinfuses those modified cells back into the person who has cancer. If the agency approves, it would mark the first time the FDA has approved anything considered to be a "gene therapy product." The treatment is part of one of the most important developments in cancer research in decades -- finding ways to harness the body's own immune system to fight cancer. And while it has generated much hope, there are some concerns about its safety over the long term -- and its cost.