Polio, a highly infectious and crippling disease, was certainly one of the most feared viruses in the 20th century. Each year, thousands of children were left paralyzed. Polio has been successfully eliminated in the U.S. for decades due to a widespread vaccine program.
So why would a group of researchers be interested in injecting the poliovirus directly into the brain of a patient? Clinical trials are now ongoing and research is revisiting the poliovirus in new and hopeful ways, ironically to help battle deadly cancers.
Glioblastoma multiforme is one of the most common and fatal brain cancers. Gliobastomas are aggressive tumors that occur in the brain or spinal cord leading to headaches, nausea, seizures, blurred vision and a host of other unpleasant effects. The tumors grow quickly and often leave patients with only months to live.
Treatments for glioblastoma involve surgery to remove the tumor, followed by radiation treatment and chemotherapy. Unfortunately, the recurrence rate for glioblastomas is near 100%, with an average time to recurrence of six to seven months. Glioblastomas will double in size every two to three weeks if left untreated. There is no FDA-approved cure, but it seem to be getting much closer each day, thanks in part to the poliovirus.
At the Preston Robert Tisch Brain Tumor Center at Duke University Medical Center in Durham, NC, medical experts have been painstakingly working on a treatment for glioblastoma for over a decade and a half. Their result: a genetically modified poliovirus, known as PVS-RIPO. How does it work?
The poliovirus is genetically modified with a portion of a rhinovirus (which causes the common cold) inserted into the poliovirus. This prevents the poliovirus from replicating and causing polio disease. The PVS-RIPO kills cancer cells but not healthy cells because it requires certain elements found only in cancer cells to be effective.
The poliovirus receptor is found on most tumor cells, and this is what allows the agent to seek out and destroy the cancer. PVS-RIPO also helps to elicit the patient’s own immune response against the cancer. The patient’s immune system recognizes the virus and initiates it’s own disease-fighting process, much the same way that a cold or cough virus is warded off.
The process of receiving the PVS-RIPO treatment is straightforward. Patients receive a 6.5 hour infusion of the PVS-RIPO treatment through a catheter inserted into the brain tumor using only a local anesthetic. No further treatment is required. Follow-up appointments, including MRI scans and neurological exams, track the treatment effectiveness, side effects, and tumor growth.
Research with PVS-RIPO is in the early stages, in Phase I trials, where clinicians are working to determine the appropriate dose in humans to kill the tumor and limit side effects. Early results have been successful in many patients and remarkably few toxic side effects, with the correct dose, have been detected. For some patients, results have been astonishing.
One young woman, a nursing student at the time, received the experimental injection in 2012. Now, three years later, no active glioblastoma cancer is present on her MRI scan. An older man, a physician has been in remission – one might call it cancer-free – for three years, too. A mom from Georgia is having success, and hopeful to see her son’s graduation. Other patients are doing well, too.
But it seems these patients may have received the correct dose. It’s important for patients to understand that overall, 11 of 22 patients have died after treatment, and complications in some may have occurred due to higher doses tested in the dose-ranging trials. The treatment is not without risk, although early results are very promising.
Studies are now moving in Phase II and III trials to determine effectiveness and get on a track towards a hopeful FDA approval. Clinical development will include more adult studies in glioblastoma, research in children with glioblastoma, and studies in other cancer types, such as prostate, melanoma, pancreas, lung, breast cancer and metastasized brain cancers that have originated from other tumors.
If you have a primary brain or spinal cord tumor, and are interested in a consultation at the Preston Robert Tisch Brain Tumor Center, please visit their referral page. Also, you may contact the Preston Robert Tisch Brain Tumor Center at Duke at (919) 684-5301. Eligible patients must meet certain requirements to enroll.
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- Duke University Medical Center. The Preston Robert Tisch Brain Tumor Center. Research Programs. Clinical trials for adults. A Phase I Clinical Trial for Recurrent Glioblastoma Patients Opens for Accrual at the Preston Robert Tisch Brain Tumor Center. Accessed March 30, 2015 at http://www.cancer.duke.edu/btc/modules/Research3/index.php?id=41
- Duke University Medical Center. The Preston Robert Tisch Brain Tumor Center. Research Programs. Clinical trials for adults. Dose-Finding and Safety Study of an Oncolytic Polio/Rhinovirus Recombinant Against Recurrent Glioblastoma Accessed March 30, 2015 at http://www.cancer.duke.edu/btc/modules/ClinicalTrials4/index.php?id=111
- Killing Cancer. CBS 60 Minutes. Aired March 29, 2015. Accessed March 30, 2015 at http://www.cbsnews.com/news/polio-cancer-treatment-duke-university-60-minutes-scott-pelley/
- Kroll D. What 60 Minutes Got Right and Wrong on Duke’s Polio Virus Trial Against Glioblastoma. Forbes. 3/30/2015. Access Match 30, 2015 at http://www.forbes.com/sites/davidkroll/2015/03/30/60-minutes-covers-dukes-polio-virus-clinical-trial-against-glioblastoma/
Last revised: March 31, 2015