New genetically engineered herpes virus kills cancer cells
A genetically modified version of the herpes virus has shown great potential in treating advanced cancers, according to a report by the Institute of Cancer Research in London published on Thursday.
A promising therapy
Although the treatment is still in early trials, researchers have found that RP2, a modified version of the herpes simplex virus, managed to kill cancer cells in a quarter of patients. The patients had cancers so advanced and complicated that they had run out of treatments to try.
“Our study shows that a genetically engineered, cancer-killing virus can deliver a one-two punch against tumors – directly destroying cancer cells from within while also calling in the immune system against them,” study leader Kevin Harrington, Professor of Biological Cancer Therapies at The Institute of Cancer Research, said in the statement.
He added that it was rare to see such positive responses in early-stage clinical trials, whose primary aim is to test for the safety of a treatment.
“Our initial trial findings suggest that a genetically engineered form of the herpes virus could potentially become a new treatment option for some patients with advanced cancers – including those who haven’t responded to other forms of immunotherapy,” Harrington explained.
“I am keen to see if we continue to see benefits as we treat increased numbers of patients.”
The newly-engineered RP2 virus is injected directly into the tumors where it functions in two ways. First, it multiplies inside cancer cells to burst them from within, effectively wiping them out.
Second,it blocks a protein known as CTLA-4 – releasing the brakes on the immune system and increasing its ability to kill cancer cells.
Finally, RP2 has also been modified to produce molecules called GM-CSF and GALV-GP-R, which give the virus additional capabilities to spark the immune system into action against cancer.
Out of nine patients treated with RP2, three saw their tumors shrink and one even saw his cancer disappear completely. He continues to remain cancer-free five months after starting treatment.
“I had injections every two weeks for five weeks which completely eradicated my cancer. I’ve been cancer free for two years now, it’s a true miracle, there is no other word to describe it,” said the patient.
The researchers then expanded their sample to 30 patients who received both RP2 and the immunotherapy nivolumab. They found that seven of those subjects benefited from the treatment.
Mild side effects
Even better, the study revealed that most side effects of RP2 were mild such as fever, chills, and fatigue. None of them were serious enough to require medical intervention.
Now, the researchers plan to continue their studies with bigger patient samples.
“Viruses are one of humanity’s oldest enemies, as we have all seen over the pandemic. But our new research suggests we can exploit some of the features that make them challenging adversaries to infect and kill cancer cells,” said Professor Kristian Helin, Chief Executive of The Institute of Cancer Research.
“It’s a small study but the initial findings are promising. I very much hope that as this research expands we see patients continue to benefit”.