March 21, 2013
Researchers Tackle Leukemia With Engineered T-Cell Therapy
Brett Smith for redOrbit.com - Your Universe Online
Job training can allow workers to take on new responsibilities and a team of oncologists from Memorial Sloan-Kettering Cancer Center (MSKCC) in New York found that the same thing applies to the body´s immune system.
Similar previous research has shown promise in young children, but the newly developed treatment was able to beat back cancer in four out of the five patients who participated in a clinical trial. The previous treatment for acute lymphoblastic leukemia (ALL) showed only about a 30-percent effectiveness for adults.
According to the oncologists´ report in journal Science Translational Medicine, T cells play a huge role in the new treatment. These cells are designed to eliminate viruses and other invaders that are studded with homing beacons that the cells can recognize. Because T cells cannot recognize certain beacons, they are not able to remove invaders such as cancer cells and some viruses.
Therefore, the oncologists decided to train the T cells to spot beacons of leukemia´s cancerous cells and eliminate them. First, the doctors removed T cells from patients with ALL. Then, the research team introduced them to a harmless virus that delivered genes for a three-part molecule into the cell. One part of the molecule allows the T cells to recognize foreign leukemia cells that are marked with an antigen called CD19. Another part of the specially designed molecule, trains T cells to kill any such marked cells they find. The third part allows the T cells to survive longer than usual.
After a 10- to 12-day ℠training process,´ the modified T cells were then returned to their five patients, ages 23, 58, 56, 59 and 66. Leukemia in four of five patients went into remission after the treatment, becoming undetectable in 18 to 59 days. Unfortunately, the fifth patient was too sick to undergo a bone marrow transplant and died.
After their treatment sessions, one of the four relapsed patients subsequently died of a blood clot. The three surviving patients have been in remission from five to 24 months, depending on when they were treated.
Despite the relative success of the treatment, the process was not without complications. After receiving the modified T cells, one patient developed a cytokine storm, in which cytokines, or hormones, are produced en masse, leading to dropping blood pressure and an intense fever. Another patient also suffered from the cytokine storm, but both patients were successfully treated with steroids.
The researchers said the results of their study reinforced the clinical approach of using the body´s own immune system to fight off the advance of cancer and keep it at bay.
"The T cells are living drugs," said study co-author Dr. Michel Sadelain. "They see the CD19, they kill the cancer cells, and they persist in the body."
The oncology team said they are currently raising funds in the hopes of performing more extensive clinical trials in the near future. They also plan to see the treatment trials expanded to other cancer centers such as the Dana-Farber Cancer Institute in Boston.