The Polio Virus and Cancer Treatment

A Possible Cure?

By Amanda C
Edited by Ali Reza

Cancer has been plaguing society for decades. While researchers have managed to eradicate and prevent numerous other diseases, cancer is one that has continued to evade them. There have been many breakthroughs and treatments which have left some patients in remission and extended the lives of others, but researchers are still seeking more effective treatments. One such approach which is gaining attention is the use of a modified polio virus to treat cancer.

Polio is a disease that scientists have virtually eliminated worldwide. There are still a few cases around, but there is a vaccine available which prevents many people from being infected. Polio can lead to paralysis and eventually death. After working so hard to prevent polio, why would they want to reintroduce it into society? Why take the risk? And that is the catch – researchers have modified the virus so that it targets cancer cells and does not trigger development of polio in patients.

A modified virus

For more than 20 years, Dr. Mattias Gromeier has been researching and experimenting with the polio virus. He found that while it does attach to neurons, which is what leads to polio, it also attaches to solid tumor cancer cells. Therefore he modified the virus to remove the sequence which causes it to attach to normal neurons, thereby making it target only cancer cells. When the virus is injected into tumors, it stimulates the body’s immune system and makes it think that there is polio present. The immune system then begins fighting off the cancer cells and ideally will kill the tumor.

Viruses have been studied for use in cancer treatment before, but this is one of the first times a virus has been able to target cancer cells. However, because polio can be a devastating disease, there has been much concern about using it for treatment. The Preston Robert Tisch Brain Tumor Center, where the research is being conducted, has tested the modified virus in animals for the last seven years to verify its safety. None of the animals in the trials developed polio. After years of research and testing, the Food and Drug Administration (FDA) finally approved the virus for clinical trials in humans.

Treating humans

Because this is only the first stage of clinical testing, researchers are still focusing on safety, but this time in humans. They have been using the modified polio virus to develop a treatment for brain tumors, or glioblastomas, but believe that it could be used to treat other types of cancer as well. Researchers are aiming to find the right dosage of the virus that will treat the tumor while producing minimal side effects. Because they are waking up the immune system to fight off the cancer cells, this can lead to inflammation. Researchers need to find a balance between injecting enough of the virus to kill the tumor, while not causing too much discomfort in the patient.

Could this be a cure for cancer?

“Cure” is a word that researchers tend to steer clear of. Instead, they focus on remission. Although they have developed other treatment methods that have helped many patients achieve remission, there is always the risk that the cancer could come back. The cancer cells figure out ways to fight off the treatment and become resistant. There is no way to accurately predict what the cancer cells might do, so researchers try to create ways to make it more difficult for the cells to survive and fight back. Immunotherapy – which is what using the modified polio virus would be – may be one technique that is harder for cancer cells to fight.

The study is still only in phase one, so there is a long way to go, but it has shown positive results thus far. None of the animals used developed polio, and so far neither have the human patients. In addition, of the 22 patients who have received the therapy so far, two are cancer-free. As the study progresses to later stages where the focus turns more toward survival after the safety has been tested, the hope is that there will be more patients who become cancer-free or have prolonged survival. Only time will tell.

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