About CAR-T leukemia therapy, part of a new wave in cancer treatment

— -- A U.S. Food and Drug Administration advisory panel endorsed a new breakthrough therapy for advanced leukemia on Wednesday called CTL019 –- a first-of-its-kind cancer treatment, in an emerging category known as CAR-T immunotherapy.

The treatment is the result of a joint effort between the University of Pennsylvania and pharmaceutical giant Novartis. In 2015, the two launched a study called ELIANA to investigate the use of CTL019 in children with a difficult-to-treat leukemia. The preliminary results of the study, released last month, helped sway the expert panel, who voted 10-0 to urge the FDA to recommend the drug for children and young adults with the devastating disease, pending approval.

The FDA is expected to make a final decision on approval by October 3. If approved, CTL019 will become the first treatment of its kind on the market. Below are some of the most important questions about this novel therapy.

How does CAR-T therapy work?

Chimeric Antigen Receptor T-cell (CAR-T) therapy leverages patients’ own immune system cells to fight tumors. Doctors extract a specialized type of white blood cells, known as T-cells, from the patient and re-engineer them to home in on and attack cancerous cells. When the modified cells are returned to the patient, they seek out and destroy the cancer.

Immunotherapy is a growing field in cancer treatment and medications that alter the body’s immune system to fight cancer are already on the market. But, CTL019 is the first that is custom-tailored for each individual patient, requiring a complex procedure that involves removing and replacing a patients’ own cells.

Who can CTL019 help?

The committee’s approval for CAR-T therapy applies to children and young adults, ages 3 to 25, with a form of leukemia called relapsed or refractory B-cell acute lymphoblastic leukemia (ALL). ALL is the most common type of cancer in children, with clinicians diagnosing about 3,000 cases in Americans below the age of 20 each year.

Traditional chemotherapy can help many children with cancer, but for those with relapsed or refractory disease, treatment options are limited and 5-year survival rates are often below 30 percent.

How well does it work?

In preliminary results of the landmark ELIANA trial, which studied 50 children with ALL over six months, researchers reported that 82 percent of patients treated with CTL019 achieved complete remission –- meaning an eradication of cancer cells –- after three months. Overall survival was 89 percent after six months and 79 percent after 12 months. The researchers plan to follow each patient for 15 years and will release information on 5-year survival rates when it becomes available.

What are the side effects?

Adverse events related to this therapy are a major concern. In the aforementioned trial, nearly eight out of 10 patients developed cytokine release syndrome, a total-body inflammatory response that mimics infection. Many of these patients required treatment in the intensive care unit (ICU), but all of them survived. Other adverse events included true infections, hallucinations and low blood cell counts. Despite the side effects, the expert committee still felt that the benefits of the therapy outweighed the risks.

Could this drug be used for other cancers?

A handful of other pharmaceutical companies are looking closely at CAR-T as a treatment option for other blood cancers, including a class of cancers known as lymphomas. Some researchers are also investigating CAR-T as a hopeful approach for treating patients with devastating solid tumors like the brain cancer glioblastoma and a form of lung cancer known as mesothelioma. Results from many of these preliminary trials are expected in the next year.