London: The virus used in the vaccine that helped eradicate smallpox is offering new hope to liver cancer patients.
Researchers have found that a genetically engineered version of the vaccinia virus tripled the average survival time of people with a severe form of liver cancer, with only mild, flu-like side effects, according to the New Scientist.
Thirty people with hepatocellular carcinoma received three doses of the modified virus - code-named JX-594 - directly into their liver tumour over one month. Half the volunteers received a low dose of the virus, the other half a high dose.
Results showed that members of the low and high-dose groups subsequently survived for, on average, 6.7 and 14.1 months respectively.
Two of the patients on the highest viral dose were still alive more than two years after the treatment.
As well as shrinking the primary tumour, the virus was able to spread to and shrink any secondary tumours outside the liver.
"Some tumours disappeared completely, and most showed partial destruction on MRI scans," noted David Kirn, head of the study at Jennerex. Moreover, the destruction was equally dramatic in the primary and secondary tumours.
The fact that the virus appears able to spread to secondary tumours suggests that simply injecting the virus into the bloodstream may be effective.
A trial to compare this treatment with injecting the virus directly into a tumour is under way.
Fischer said that until now, more than 200 people have received the virus, which has also shown promise against other types of cancer, including those of the kidney and skin.
But he warns that not everyone sees a benefit.
"We know why patients respond, but not why they don`t," he added.