(Reuters) - Novartis AG's NOVN.S pioneering new cancer drug won enthusiastic support from a federal advisory panel on Wednesday, paving the way for approval of the first U.S. gene therapy.

FILE PHOTO : A sign marks a building on Novartis' campus in Cambridge, Massachusetts, U.S. on February 28, 2017. REUTERS/Brian Snyder/File Photo

The panel unanimously recommended that the Food and Drug Administration approve the drug, tisagenlecleucel, for patients ages 3 to 25 with relapsed B-cell acute lymphoblastic leukemia (ALL), the most common form of U.S childhood cancer.

The drug uses a new technology known as CAR-T, or chimeric antigen receptor T-cell therapy, which harnesses the body’s own immune cells to recognize and attack malignant cells.

In a clinical trial, 83 percent of patients who had relapsed or failed chemotherapy achieved complete or partial remission three months post infusion. After one year 79 percent of patients were still alive.

Patients with ALL who fail chemotherapy typically have only a 16 percent to 30 percent chance of survival.

“This is a potentially paradigm-changing type of benefit,” said Dr. Brian Rini, a panelist and physician at Cleveland Clinic Taussig Cancer Institute.

The FDA is not obliged to follow the recommendations of its advisers but typically does so. The agency is expected to rule on the drug by the end of September.

Approval of tisagenlecleucel would have significant implications not only for Novartis but for companies developing similar treatments, including Kite Pharma Inc KITE.O, Juno Therapeutics Inc JUNO.O and bluebird bio Inc BLUE.O.

It would also advance a technique scientists have been attempting to perfect for decades and help lift the entire field of cell therapy.

"This will be a historic approval," said Brad Loncar, chief executive of Loncar Investments which runs the Loncar Cancer Immunotherapy ETF CNCR.O. "As an investor I've never seen anything like it. It's an entirely new way of treating cancer."

The product is made by extracting and isolating a patient’s T cells, genetically engineering them to recognize and target cancer cells, and then infusing them back into the patient. Novartis said the entire process will take 22 days by the time it is launched.

The treatments are given just once and are expected to cost up to $500,000. Loncar said approval of tisagenlecleucel would represent an inflection point for investors.

“Any time a new technology crosses the finish line at the FDA, it gets noticed and I think you’ll see a rush of investment and see these therapies be improved over time.”

More than half of patients experienced a serious complication known as cytokine release syndrome (CRS) which occurs when the body’s immune system goes into overdrive. Doctors were able to manage the condition and the syndrome caused no deaths.

The FDA expressed concern that the drug could cause new malignancies over the long term. Panelists generally felt that risk was low and they said Novartis’s risk mitigation proposals were adequate.

Novartis is also testing the drug in diffuse large B-cell Lymphoma (DLBCL), the most common form of non-Hodgkin lymphoma, as is Kite.

Novartis's stock NVS.N closed up 1.5 percent at $83.21 in U.S. trading. The shares NOVN.S finished up 2.2 percent at 80.5 Swiss francs in Zurich before the vote was taken.