The Hunt for a Brain Tumor Vaccine

Date: November 1, 2011

Johns Hopkins neuroscience researcher, Betty Tyler

Wouldn’t it be great if we could cure brain tumors with a shot and make sure they never came back?” asks Michael Lim. There’s reason to be hopeful that this sort of extraordinary breakthrough is on the horizon, thanks to research being conducted by Lim, a neurosurgeon-scientist who directs the Johns Hopkins Metastatic Brain Tumor Center, and Johns Hopkins neuroscience researcher Betty Tyler and other colleagues.

Their research mainly targets glioblastomas, brain tumors known for their aggressive growth and the difficulty of treating them. Drugs can slow the tumors’ growth, and to help these drugs pack their toxic punch against the tumor and not elsewhere, neurosurgeon Henry Brem and Johns Hopkins researchers developed dissolving polymer wafers that can be implanted at the tumor site. Now Tyler is among those who have been conducting animal studies to determine which drugs work best with these wafers. Tyler, Brem and others are also looking at implantable microchips that can be programmed to release multiple drugs at different rates, times and sequences to avoid drug interactions. “There’s a constant push here to get just the right combination and timing of drugs to wipe out the tumor with minimal harm to the patient,” says Tyler.

Lim, meanwhile, is trying to find ways to get the body’s immune system to attack the tumors. “Our immune systems kill cancerous cells all the time,” he says. “But some cancer cells develop the ability to turn off the immune system response, and those are the ones that become tumors.” Lim and others are investigating molecules that seem to block the chemical signals that a tumor secretes to steer away immune cells. Lim’s lab is also working with antibodies that allow the immune cells to ignore the suppressive signals and come charging in to kill the tumor cells. In the laboratory, these antibodies have cured mice with glioblastomas, suggesting the antibodies may be a key step towards a brain-tumor vaccine. A clinical trial of the antibodies for glioblastoma patients will be starting soon. “We want to give patients immunity to these tumors in the truest sense of the word,” says Lim. “We still have a long way to go, but we’re very excited about the progress we’re making.”

• Challenge: Stop aggressive brain tumors
• Approach: Deliver drugs on microchips and energize the immune system
• Progress: Mice have been cured; patient trials are starting