Herpes virus could soon be approved to treat severe skin cancer

Despite many decades of effort and many human tests, only one virus designed to kill cancers has never been approved by regulators in the United States and Europe. But a second could obtain the green light at the end of the month, after having obtained good results for the treatment of melanoma, a particularly serious type of skin cancer.

A genetically modified herpes virus called RP1, was injected into tumors of 140 people with advanced melanoma for which standard treatments had failed. Participants also took a medication called Nivolumab, which is designed to stimulate the immune response to tumors.

In 30% of people treated, tumors have shrunk, including those who have not been injected. In half of these cases, the tumors have completely disappeared.

“Half of the speakers have had complete answers, which means the complete disappearance of all tumors,” said Gino Kim at the University of Southern California. “We are very excited by these results.” The other options to treat people at this stage do not work as well and have more serious side effects, he said.

A test at a later stage that will involve 400 people is underway, but RP1 could be approved by the Food and Drug Administration (FDA) in the United States for having treated advanced melanoma in combination with the Nivolumab well before the end of this test, in Tot New scientist. “The FDA is supposed to give us a decision at the end of this month.”

We have known for over a century that viral infections can sometimes help treat cancers, but deliberately infect people with “wild” viruses is very risky. In the 1990s, biologists began to genetically modify viruses to try to improve them to treat cancer, but unable to harm healthy cells.

These viruses are designed to operate in two ways. First, by directly infecting cancer cells and killing them by bursting them. Second, by triggering an immune response that targets all cancer cells, wherever they are in the body.

For example, a simplex herpes virus known as T-with, or Imlygic, has been modified to ensure that infected tumor cells release an immune factor called GM-CSF, among other changes. In 2015, T-with was approved in the United States and Europe for treating inoperable melanoma.

But T-With is not widely used, said in part, in part because it has only been tested and approved for injection in tumors in the skin. Most people with advanced melanoma have deeper tumors, he said.

With RP1, the decision was also made to try to inject it into deeper tumors. RP1 is a virus of herpes Simplex, like T-with, but has been improved in many ways. In particular, this means that tumor cells merge with neighboring cells, helping the virus spread through tumors and stimulating the immune response.

There were no directly comparable tests of T-with and RP1, but RP1 is more likely to encourage the narrowing of all tumors, not only injected, said in. “This indicates a more powerful systemic effect.”

Therefore, in the meantime, RP1 is much more widely used than it is approved. It will also give a big boost to the whole idea of ​​using viruses killing cancer, he said. “I expect it to be much more interest.”