Cancer cells are really smart. They can hide out during treatment. Or they can resist treatment only to appear later. They can also avoid the body's defense system. Brain cancer researchers may have found a way to outsmart these smart cells.
A therapy being studied helped patients with aggressive brain tumors live much longer than they normally do with standard treatment.
Researchers at Cedars-Sinai Medical Center have developed a vaccine that helps the immune system attack these tumors called glioblastoma multiforme (GBM).
In a Phase I clinical trial, which tests drug safety, participants lived a median (middle number) of 38.4 months. Typical lifespan with these tumors is 14.6 months after standard therapy which includes radiation and chemotherapy.
The time before the tumor returned was also longer - 16.9 months compared to 6.9 months. This is called progression-free survival.
The trial involved 16 newly diagnosed patients who were followed from May 2007 to January 2010. Some 49 to 66 months following treatment, six patients were free of the disease, and the tumor had not returned. Another eight patients were still alive.
"What stands out in this study of GBM is that six out of 16 patients are alive and disease free longer than four years, and three out of 16 are disease-free longer than five years after diagnosis," Keith L. Black, MD, chair and professor of Cedars-Sinai’s Department of Neurosurgery, told dailyRx in an email.
The vaccine goes after six antigens (a marker on the surface of a cell that causes the immune system to respond) that help develop GBM cells. The antigens involved are HER2/neu, TRP-2, gp100, MAGE-1, IL13Ra2 and AIM-2. Patients in the study had between three and six of these antigens.
The experimental therapy also attacks brain cancer stem cells. The stem cells help tumors resist radiation and chemotherapy only to come roaring back after treatment.
Killing stem cells is thought to be effective in eliminating the tumor and keeping it from coming back.
This therapy - currently called ICT-107 - is known as a dendritic cell vaccine. Dendritic cells help the body's immune system identify invaders. These cells are made from the body's white blood cells.
The vaccine is given by injection, and it works by seeking and destroying tumor cells.
"This long-term tail in the survival curve is very suggestive of a real benefit from the treatment," said Dr. Black, who is director of the Cochran Brain Tumor Center and director of the Maxine Dunitz Neurosurgical Institute, where the vaccine was developed.
"We are hopeful that these results hold up in the phase II study," said Dr. Black, who is also the Ruth and Lawrence Harvey Chair in Neuroscience.
This study was published August 3 in the journal Immunotherapy.
The vaccine is a product of Immunocelllular Therapeutics. Dr. Black is chairman of the company's scientific advisorty board. Other study authors also have financial relations with this company, and Cedars-Sinai owns stock in the firm.