A modified herpes virus has shown promise in killing cancer cells, with one patient seeing the disease disappear completely.
The patients were injected with a drug that was a weakened form of the cold sore virus, herpes simplex, that has been modified to kill tumors.
Although more research is needed, it could offer a lifeline for those living with advanced cancer.
Krzysztof Wojkowski, 39, a builder from west London, went from end-of-life care to cancer-free after joining the trial.
Wojkowski was diagnosed with mucoepidermoid carcinoma, a type of salivary gland cancer, in May 2017.
Despite multiple surgeries, he was told there were no treatment options left, before being given the chance to join the RP2 trial at The Royal Marsden in 2020.
He said: “I was told I had no options left and was getting end of life care, it was devastating, so it was amazing to be given the opportunity to join the trial at The Royal Marsden, it was my last lifeline..
“I had injections every two weeks for five weeks which completely eradicated my cancer. I’ve been cancer free for two years, it’s a real miracle, there’s no other word to describe it.
“I’ve been able to get back to work as a builder and spend time with my family, there’s nothing I can’t do.”
The genetically modified virus, which is injected directly into tumors, is designed to have a double action: it multiplies inside cancer cells to burst them from within, and it also blocks a protein known as CTLA-4 , releasing the brakes on the immune system and increasing its ability to kill cancer cells.
Image: Image: Salivary gland carcinoma. Credit: Nephron, CC BY-SA 4.0, via Wikimedia Commons
It’s rare to see such promise in early trials
Three out of nine patients treated with RP2 saw their tumors shrink.
Seven of 30 patients who received both RP2 and nivolumab immunotherapy also benefited from the treatment.
In this group, four out of nine melanoma skin cancer patients, two out of eight eye cancer uveal melanoma patients, and one out of three head and neck cancer patients saw the growth of their cancer
Of the seven patients who received the combination who saw a benefit, six remained progression-free at 14 months.
It’s rare to see such a good response rate in early-stage clinical trials, according to study leader Professor Kevin Harrington, professor of biological cancer therapies at the Institute of Cancer Research in London and a consultant oncologist from The Royal Marsden NHS Foundation Trust. .
He said: “Our study shows that a genetically engineered, cancer-killing virus can deliver a two-hit attack on tumors by directly destroying cancer cells from the inside and also calling out the immune system against them.
“It is rare to see such good response rates in early-stage clinical trials, as their main purpose is to test the safety of the treatment and they include patients with very advanced cancers for which current treatments have stopped working.
“Our initial trial results suggest that a genetically modified form of the herpes virus could become a new treatment option for some patients with advanced cancer, including those who have not responded to other forms of immunotherapy
“I’m interested to see if we continue to see benefits as we treat increasing numbers of patients.”
Taking advantage of the characteristics of viruses
Professor Kristian Helin, chief executive of the Institute of Cancer Research in London, said it is possible to exploit some of the characteristics of viruses.
They said: “Viruses are one of humanity’s oldest enemies, as we’ve all seen during the pandemic. But our new research suggests we can exploit some of the features that make them challenging adversaries to infect and kill cells cancerous
“It’s a small study, but the initial findings are promising. I really hope that as this research expands, we’ll see patients continue to benefit.”