Targeting tumors, protecting tissue, saving lives
Almost three years later, Bibbís tumor has shrunk to almost nothing, and with few side effects, the mother of three is able to keep up with her three busy boys and the things that are most important to her.
"Dr. Brenner was so excited when he knew he could get me on this study," she said. "He had a reason to be excited, because itís worked, more than even he thought it would."
For Bibb, it was also a modern wonder to be able to take this experimental therapy in the form of a pill. It was also a huge help for her, as the young family had moved to Tyler, Texas.
"To have a chemo in a pill form - thatís amazing to me. Itís so important to do that kind of research."
Clinical trials donít just give researchers the opportunity to test new drugs. They also help find new ways of delivering known therapies so that they will be more effective.
Dr. Brenner is in the midst of developing a clinical trial for just such a promising new method of delivery.
For the past 40 years, radiation has been the most effective method for treating deadly brain tumors called glioblastomas. Although the targeting technology has been refined, beams of radiation still must pass through healthy brain tissue to reach the tumor, and patients can only tolerate small amounts before developing serious side effects.
A group of researchers at the UT Health Science Center San Antonio has developed a way to deliver nanoparticle radiation directly to the brain tumor and keep it there. The method doses the tumor itself with much higher levels of radiation - 20 to 30 times the current dose of radiation therapy to patients - but spares a much greater area of brain tissue.
The study, published today in the journal Neuro-Oncology, has been successful enough in laboratory experiments that theyíre preparing to start a clinical trial at the Cancer Therapy & Research Center, said Andrew Brenner, M.D., Ph.D., the studyís corresponding author and a neuro-oncologist at the CTRC who will lead the clinical trial.
"We saw that we could deliver much higher doses of radiation in animal models," Dr. Brenner said. "We were able to give it safely and to completely eradicate tumors."
The radiation comes in the form of an isotope called rhenium-186, which has a short half-life. Once placed inside the tumor, the rhenium emits radiation that only extends out a few millimeters.
But simply putting the rhenium into a brain tumor would not work well without a way to keep it there - the tiny particles would be picked up by the bloodstream and carried away. That problem was solved by a team led by nuclear medicine physician William T. Phillips, M.D., and biochemist Beth A. Goins, Ph.D., in the Department of Radiology; and Ande Bao, Ph.D., a medical physicist and pharmaceutical chemist in the Department of Otolaryngology, all of the School of Medicine at the Health Science Center. They encapsulated the rhenium in minuscule fat molecules, or liposomes, about 100 nanometers across.
"The technology is unique," Dr. Brenner said. "Only we can load the liposomes to these very high radioactivity levels using a specific compound called BMEDA made to trap radiation in these tiny fat molecules. This compound was not available before Drs. Goins and Phillips created it. Now we can deliver these radioactive liposomes into the tumor where the cancer cells eat them up."
The doctors hope to launch the clinical trial by summer.
"Patients like Terra are the reason I do what I do every day," Dr. Brenner said. "My job is to find new ways in the lab to kill brain tumors and then take these remedies into the clinic to help my patients. Sometimes it means trying something that no one else has thought of, or teaming up with other scientists. Of utmost importance is our role in helping our patients live as normally as possible, and we are committed to doing that any way we can."
For more information about clinical trials at the CTRC, call 210-450-5798.
Center for Innovation in Drug Discovery translates homegrown discoveries
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