Last week, an FDA panel unanimously recommended that the agency approve a treatment that genetically alters a patient’s immune cells to fight leukemia from within. This kind of “living drug,” called gene therapy, would be the first of its kind on the market in the United States if the FDA approves it.
The treatment has to be created from scratch for each individual patient, using their own T cells—white blood cells used by the immune system. T cells are removed from patient’s bloodstream, then genetically engineered to recognize and kill cancer. The weaponized cells are then multiplied and reintroduced into the patient.
Novartis, the company seeking approval for the first therapy, presented data from an 18-month study in which 52 out of 63 patients with B-cell acute lymphoblastic leukemia went into remission.
The products that are closest to approval focus on blood cancers like leukemia and lymphoma, which represent about 80,000 of the 1.7 million cancer diagnoses in the United States each year.
Here’s Denise Grady, reporting for The New York Times:
“This has been utterly transformative in blood cancers,” said Dr. Stephan Grupp, director of the cancer immunotherapy program at the Children’s Hospital of Philadelphia and a professor of pediatrics at the University of Pennsylvania. “If it can start to work in solid tumors, it will be utterly transformative for the whole field.”
Solid tumors are highly resistant to the kinds of altered T cells that have have proven effective against blood cancers. Although researchers are working on approaches for solid tumors, the challenge they present means that gene therapies may be further off for breast, ovarian, prostate, lung and pancreatic cancers, for example.
But T-cell approaches aren’t the only thing out there. Researchers at the University of Texas MD Anderson Cancer Center are harnessing the power of so-called natural killer cells, another kind of immune cell that can be genetically altered to attack cancer. Unlike T cells, natural killer cells can be taken from cord blood donated at childbirth, and the modified cells can be safely given to multiple patients. What’s more, they have a kind of drug-activated “off switch,” which can be flipped in the event that the treatment causes unmanageable side effects.
After “promising” studies in mice, the researchers have opened a study for patients with relapsed or treatment-resistant leukemia and lymphoma. The first patient is to be treated with the natural killer cell method this week.