Preliminary research shows that gene therapy might one day be a powerful weapon against leukemia and other blood cancers.
The experimental treatment coaxed certain blood cells into targeting and destroying cancer cells, according to research presented this weekend at the American Society of Hematology's annual meeting in New Orleans.
"It's really exciting," Dr. Janis Abkowitz, blood diseases chief at the University of Washington in Seattle and president of the American Society of Hematology, told the Associated Press. "You can take a cell that belongs to a patient and engineer it to be an attack cell."
At this point, more than 120 patients with different types of blood and bone marrow cancers have been given the treatment, according to the wire service, and many have gone into remission and stayed in remission up to three years later.
In one study, all five adults and 19 of 22 children with acute lymphocytic leukemia (ALL) were cleared of the cancer. A few have relapsed since the study was done.
In another trial, 15 of 32 patients with chronic lymphocytic leukemia (CLL) initially responded to the therapy and seven have experienced a complete remission of their disease, according to a news release from the trial researchers, who are from the University of Pennsylvania.
All the patients in the studies had few options left, the researchers noted in the news release. Many were ineligible for bone marrow transplantation or did not want that treatment because of the dangers associated with the procedure, which carries at least a 20 percent mortality risk.
The gene therapy could become a much needed alternative for those with blood cancers.
"Our findings show that the human immune system and these modified 'hunter' cells are working together to attack tumors in an entirely new way," research leader Dr. Carl June, professor in immunotherapy in the department of pathology and laboratory medicine and director of translational research at Penn's Abramson Cancer Center, said in the news release.
Penn researchers have treated the most patients, 59, with this gene therapy. Scientists at the U.S. National Cancer Institute, Memorial Sloan-Kettering Cancer Center in New York City, and the University of Texas MD Anderson Cancer Center and Baylor University in Houston have treated smaller groups of patients, according to the AP.
In the studies, researchers filtered the patients' blood, removing white blood cells known as T-cells that are part of the body's immune system. They then added a gene to the T-cells that would target cancer cells. The altered T-cells were returned to the patients' body in infusions that were given over the course of three days.
Several companies are developing these types of cancer therapies, and a clinical trial next year could lead to federal approval of the treatment by 2016, the AP reported.
"From our vantage point, this looks like a major advance," Lee Greenberger, chief scientific officer of the Leukemia and Lymphoma Society, told the AP. "We are seeing powerful responses... and time will tell how enduring these remissions turn out to be."
The gene therapy must be made individually for each patient, and lab costs now are about $25,000, without a profit margin, the AP reported.
The treatment can cause severe flu-like symptoms and other side effects, but these have been reversible and temporary, doctors said.
-- HealthDay staff
