Clinical trial of experimental vaccine targets cancer stem cells in patients with recurrent brain tumor

An early-phase clinical trial of an experimental vaccine that targets cancer stem cells in patients with recurrent glioblastoma multiforme, the most common and aggressive malignant brain tumor, has been launched by researchers at Cedars-Sinai's Department of Neurosurgery, Johnnie L. Cochran, Jr. Brain Tumor Center and Department of Neurology.

Like normal stem cells, cancer stem cells have the ability to self-renew and generate new cells, but instead of producing healthy cells, they create cancer cells. In theory, if the cancer stem cells can be destroyed, a tumor may not be able to sustain itself, but if the cancer originators are not removed or destroyed, a tumor will continue to return despite the use of existing cancer-killing therapies.

The Phase I study, which will enroll about 45 patients and last two years, evaluates safety and dosing of a vaccine created individually for each participant and designed to boost the immune system's natural ability to protect the body against foreign invaders called antigens. The drug targets a protein, CD133, found on cancer stem cells of some brain tumors and other cancers.

Immune system cells called dendritic cells will be derived from each patient's blood, combined with commercially prepared glioblastoma proteins and grown in the laboratory before being injected under the skin as a vaccine weekly for four weeks and then once every two months, according to Jeremy Rudnick, MD, neuro-oncologist in the Cedars-Sinai Department of Neurosurgery and Department of Neurology, the study's principal investigator.

Dendritic cells are the immune system's most powerful antigen-presenting cells - those responsible for helping the immune system recognize invaders. By being loaded with specific protein fragments of CD133, the dendritic cells become "trained" to recognize the antigen as a target and stimulate an immune response when they come in contact.

The cancer stem cell study is the latest evolution in Cedars-Sinai's history of dendritic cell vaccine research, which was introduced experimentally in patient trials in 1998.