An unusual and experimental cancer treatment is currently being tested by the Mayo Clinic and is showing good signs – injecting people with high doses of measles vaccine.
Some results have been impressive including a woman with widespread blood cancer who received the injection and went into complete remission afterwards. The injection of measles vaccine is enough to inoculate 10 million people, so a massive amount of vaccine is used.
It turns out the vaccine plays an unusual role when cancer and tumors are found within the body. The theory goes that a single massive dose of the vaccine can be used to kill the cancer by overwhelming it’s natural defenses.
Dr. Stephen Russell, a professor of molecular medicine at Mayo Institute says of the treatment: “It’s a landmark. We’ve known for a long time that we can give a virus intravenously and destroy metastatic cancer in mice. Nobody’s shown that you can do that in people before.”
The research is in extremely early stages with the initial findings just published in the journal Mayo Clinic Proceedings. However researchers in the field like Dr. John C. Bell from the Centre for Innovative Cancer Research suggests: “Without trying to hype it too much, it is a very significant discovery”
The next step is to expand the size of the trial to a few hundred patients to see if the results can be replicated. According to Mayo, that trial should begin before September 2014.
So how does it work?
Cancer researchers have understood for a long time that viruses can kill cancer cells and tumors. The virus can bind itself to tumors within the body and use them to replicate their own genetic material. So the measles virus will latch onto tumors and use them to replicate. The cancer cells eventually explode and release more of the virus, the fantastic part is that the cancer cells are devastated by the virus. There are a number of antiviral vaccines like the measles vaccine that have been rendered safe and can attack cancer cells.
An additional benefit is that thanks to recent progresses, the viruses can be modified to carry radioactive molecules that destroy cancer cells without damaging healthy tissue. The human body’s immune system will also be seeking to eradicate the virus, so any cancer cells that look like a part of the virus will be attacked, including those tumors that have been attacked by the virus.
Other viruses that may be used to attack cancer cells include herpes and poxvirus, which have shown fantastic results in rats. Researchers have been unsure what level of viral infection would be required to combat cancer effectively and this recent study indicates that a substantial amount is most likely required to overcome the defense mechanisms that cancerous tumors have.
Researchers also suggest that because different viruses tend to target certain parts of the body, they may be more effective against cancers that appear in that part of the body. For example the common influenza virus may be the most effective for attacking lung cancer. That would mean that a modified virus wouldn’t cause damage to other parts of the body!
The measles vaccine used looked at the cancerous myleoma tumors as a form of food and literally gobbled them up to reproduce. Of course most people have already been vaccinated for measles, so the treatment would be less effective as their system would attack the virus quickly. However that is somewhat mitigated because cancer patients often have compromised immune systems and the virus can spread more effectively. Drugs could be used to help the virus work throughout the body as well.
Researchers had to establish how much of the virus to give patients and there is still some work to be done to determine the right amount of the virus on a case by case basis. Some patients might only need a couple of million infectious units, others might need billions, as was used in the successful case study.
The study used only 2 patients, with the woman who had tumors in her bone marrow showing complete recovery, but the woman with tumors in her leg muscle showing any substantial improvement. Researchers suggest that more research is needed to determine a better virus for tumors in that location or an increase in dosage.
This form of viral treatment is a one off, because after it has been used the body will recognize the virus and attack it quickly. Researchers will also take a look at reducing the effectiveness of the immune system so repeated courses of a virus may be used if required. One approach there is to take the patients cells, load the virus into them and inject them back into the body. That gives the virus time to reach the tumors and attack them before the immune system kills the virus.
Another current study is looking at treating pancreatic cancer with Reolysin, which is a variation of the virus that causes the common cold. In this study, researchers are also looking at the prospect of injecting tumors directly with the virus as opposed to using the bloodstream as a viral delivery mechanism.
Doctors are very excited about the possibilities with one researcher saying viral treatment is: “an incredibly innovative way to actually attack the cancer and perhaps even offer a better chance at complete remission”.
It is still early days, and large scale randomized trials are required, but the early results are very encouraging!