First Gene Therapy Treatment Approved in U.S.

By modifying a person’s own immune cells, the treatment can effectively target leukemia cells

Gene Therapy
Genetically modified immune cells ready to be reintroduced back into a person and attack leukemia. Penn Medicine

The Food and Drug Administration has signed off on the United States' first approved gene therapy treatment, clearing a new medical pathway in the country.

"We’re entering a new frontier in medical innovation with the ability to reprogram a patient’s own cells to attack a deadly cancer," FDA Commissioner Scott Gottlieb says in a statement. "New technologies such as gene and cell therapies hold out the potential to transform medicine and create an inflection point in our ability to treat and even cure many intractable illnesses."

The "historic action," as the FDA called it, approves a treatment by the drug company Novartis for juvenile acute lymphoblastic leukemia, reports Jocelyn Kaiser for Science magazine. For the therapy, immune T cells are taken from a person's blood and modified to add a gene that creates a protein that entices the T cells to attack the leukemia cells.

Unlike a standard chemotherapy drugs given to many patients, this method, referred to as CAR-T immunotherapy, essentially creates a custom treatment for each individual, reports Damian Garde for STAT News. A single dose of the treatment, called Kymriah by its developer, left 83 percent of its patients cancer-free after three months in a clinical trial.

But it's not all good news. The treatment will cost $475,000, reports Garde, which, although pricey, is much less than many outsider observers expected. Patients will have to travel to one of 32 locations across the U.S. to have their T cells extracted and modified in a 22-day process. And as Kaiser reports, shortages during clinical trials have already posed an issue at some medical centers.

And for all of its benefits, this treatment can come with some frightening side effects, reports Beth Mole for Ars Technica. The most intense one is cytokine release syndrome, when the immune system can go into overdrive attacking the body, causing inflammation, organ failure, seizures, delirium, brain swelling and, in some cases, even death. For now, Kymriah is only approved for use on people under age 25 who've already tried a more conventional leukemia treatment and had a relapse.

Though the FDA refers to it as a gene therapy, some experts have questioned their definition of that term, writes Kristen Brown for Gizmodo. The disagreement stems from the fact that the modified gene isn't itself curing anything or fixing a biological defect. Rather the treatment redirects the T cell to fight the disease.

Even so, this latest approval is an exciting step in the fight against cancer. Before this decision, gene therapy treatments have previously met regulatory approval in the Europe and China, reports Kaiser. As genetic editing continues to gain traction in science and medicine in the U.S., further approvals are likely to come, notes Kaiser, including a possible treatment that could cure congenital blindness.