Glioblastoma—it’s one of the most deadly forms of cancer. About 10,000 Americans are diagnosed each year with this aggressive brain tumor. Now, there’s a new treatment that may offer hope.
Burhan and Renee Oral know moments like these are precious. Burhan has glioblastoma – an aggressive brain cancer.
“They told me I had three to six months to live,” Burhan told Ivanhoe.
“Never ever, ever give up. That’s what I tell him,” Renee told Ivanhoe.
Five surgeries and 2 ½ years later—Burhan is still here, but his cancer came back a few months ago.
“It’s very much like we are playing chess with the tumor cells. For every drug we give it, the tumor cells could make a move,” Clark Chen, MD, PhD, Vice Chairman of Neurosurgery, University of California, San Diego, told Ivanhoe.
Dr. Clark Chen told Burhan about a clinical trial testing a new, minimally invasive treatment for glioblastoma. First—he makes a small hole in the skull. Using MRI to guide a catheter to the brain, he then injects a virus directly into the tumor, which lights up on scans.
“So, we can actually see in real-time where the virus is as we inject it,” Dr. Chen said.
The patient then takes a powerful anti-fungal drug that goes into every cell in the body. The virus activates the drug, telling it to attack the tumor.
“What we are able to see is that the area where the viruses are injected, the tumor is melting away,” Dr. Chen said.
Since the treatment, scans show no signs of cancer growth and Burhan continues to hope for the best.
The treatment is given as part of a phase one clinical trial. It’s considered a minimally-invasive brain procedure, and patients are discharged one day after having it. Because it’s a targeted approach, Dr. Chen says there are fewer side effects. In fact, he hasn’t observed any unwanted side effects in his patients.
BACKGROUND: Glioblastoma is an aggressive, malignant brain tumor; also known as grow-and-go tumors, they grow very quickly in their original site and they move quickly to new sites in the body. These tumors develop in cerebral hemispheres, but may also appear in other parts of the brain, spinal cord, or brain stem. They stem from glial cells from tissue surrounding the spinal cord and brain. (Source: http://www.braintumor.org/patients-family-friends/about-brain-tumors/tumor-types/glioblastoma-multiforme.html?gclid=CPrK1KHT3boCFUPl7AodewoAbQ)
SYMPTOMS: Symptoms of glioblastoma depend on the location of the tumor, but typical symptoms include: headache, nausea, memory loss, confusion, change in vision, change in speech, change in mood, nerve pain or numbness, and seizures. (Source: http://www.gliadel.com/gbm-treatment/symptoms/)
NEW TREATMENT: Neurosurgeons at the University of California, San Diego School of Medicine are among the first in the world to utilize real-time magnetic resonance imaging (MRI) guidance for delivery of gene therapy as a potential treatment for brain tumors. Using MRI navigational technology, neurosurgeons can inject Toca 511, an investigational gene therapy, directly into a brain malignancy. This new approach offers a way to precisely deliver a therapeutic virus designed to make the tumor susceptible to cancer-killing drugs. “With chemotherapy, just about every human cell is exposed to the drug’s potential side-effects. By using the direct injection approach, we believe we can limit the presence of the active drug to just the brain tumor and nowhere else in the body,” Clark Chen, MD, PhD, chief of stereotactic and radiosurgery and vice-chairman of neurosurgery at UC San Diego Health System, was quoted as saying. “With MRI, we can see the tumor light up in real time during drug infusion. The rest of the brain remains unaffected so the risk of the procedure is minimized.”
Toca 511 is a retrovirus engineered to replicate in cancer cells, like glioblastomas. It produces an enzyme that converts an anti-fungal drug, flucytosine (5-FC), into the anti-cancer drug 5-fluorouracil (5-FU). After the injection of Toca 511, the patients are treated with an investigational extended-release oral formulation of 5-FC called Toca FC. The cancer cells begin to die when 5-FX comes into contact with cells infected with Toca 511. To ensure that the adequate amount of Toca 511 is delivered to the region of the tumor, neurosurgeons use state-of-the art MRI guidance, called ClearPoint, to monitor the delivery and injection processes in real time. It provides visual confirmation that the desired amount of drug is delivered into the tumor and provides physicians the ability to make adjustments to optimize the location of drug delivery. (Source: http://ucsdnews.ucsd.edu/pressrelease/southern_californias_first_real_time_mri_guided_gene_therapy_for_brain_canc)
Clark Chen, MD, PhD, Vice Chairman of Neurosurgery at University of California at San Diego, talks about a new way to treat patients with glioblastoma.
How many glioblastomas do you treat in a day, a week, a year?
Dr. Chen: Glioblastoma is a fairly rare disease. There is an estimated 10,000 cases in the entire U.S. and it’s in large part because of its rarity that it’s considered an orphan disease. We tend to work on diseases that our loved ones are inflicted by and because glioblastoma is such a rare disease, it’s not being worked on as much as the other tumors. On average, at UCSD, we treat somewhere between 150 and 200 tumors of this nature per year.
So, glioblastomas are very hard to treat, right?
Dr. Chen: They are extremely difficult to treat. It is one of the most resistant tumors to radiation and chemotherapy. Many, very prominent public figures have been inflicted with this disease and have gotten really the best possible care and without fail, all of them died within a year of diagnosis; people like Senator Kennedy, Siskel of Siskel and Ebert, Johnny Cochran of the O.J. Simpson trial.
Is that because glioblastoma has what I call fingers? It just grows through the brain?
Dr. Chen: That’s exactly right. The tumor is extremely infiltrative. What you are referring to are, are finger-like projections that send out little colonies, little colonies of tumor, apart from where we can see them. So, it is very difficult to remove the tumor in its entirety by surgery. Chemotherapy is absolutely warranted. In addition, there is a challenge that’s unique to glioblastomas, which is that there is this barrier that protects our brain, called the blood brain barrier, and normally it protects our brain from the effect of viruses and certain drugs. The problem is when you have this barrier and you have a tumor in there, the tumors are also protected from the drugs. So, when we give a drug to the patient, it’s never clear whether the drug got to the tumor at all.