August 31, 2011
New Virus Shows Promise In Fighting Cancer
Researchers have engineered a virus that can selectively target cancer cells throughout the body.
According to the team, the virus attacked only tumors during a small trial on 23 patients, leaving the healthy tissue alone.
Researchers said the findings could one day "truly transform" therapies.
Scientists modified the vaccinia virus, which is famous for being used to develop a smallpox vaccine.
The virus is dependent on a chemical pathway in order to replicate.
It was injected at different doses into the blood of 23 patients with cancers. Seven of the eight patients who received the highest dose had the virus replicating in their tumors.
Prof John Bell, lead researcher and from the University of Ottawa, said in a statement: "We are very excited because this is the first time in medical history that a viral therapy has been shown to consistently and selectively replicate in cancer tissue after intravenous infusion in humans.
"Intravenous delivery is crucial for cancer treatment because it allows us to target tumors throughout the body as opposed to just those that we can directly inject."
Infection prevented further tumor growth in six of the patients. The patients were only given one dose of the virus because the trial was designed to test the safety of the virus.
Bell said that the research is still in the early stages, but "I believe that some day, viruses and other biological therapies could truly transform our approach for treating cancer."
Cancer Research UK's Prof Nick Lemoine, also director of Barts Cancer Institute, said in a statement: "Viruses that multiply in just tumor cells - avoiding healthy cells - are showing real promise as a new biological approach to target hard-to-treat cancers.
"This new study is important because it shows that a virus previously used safely to vaccinate against smallpox in millions of people can now be modified to reach cancers through the bloodstream - even after cancer has spread widely through the patient's body.
"It is particularly encouraging that responses were seen even in tumors like mesothelioma, a cancer which can be particularly hard to treat."
The research was published in the journal Nature.
On the Net:
- University of Ottawa
- Cancer Research UK
- Barts Cancer Institute
- Video: Oncolytic Vaccinia Virus Infecting a Human Tumor