As part of a clinical trial, the world’s first patient was injected with an experimental cancer-killing virus. If the trials are successful, medicine will receive a new tool to fight cancer.

The test drug CF33-hNIS (or Vaxinia) is an oncolytic virus – a genetically modified virus. It selectively infects and destroys cancer cells while maintaining human health.

CF33-hNIS is a modified variola virus that enters cells and replicates itself. The infected cell releases thousands of new viral particles, which in turn stimulate the immune system to attack nearby cancer cells.

Animal studies have shown that the drug uses the human immune system to find and destroy cancer cells. But human trials weren’t done until recently.

The developers of the drug, City of Hope Research Center in Los Angeles, and Australian biotechnology company Imugene have officially announced the start of the first human clinical trial.

“Previous research shows that oncolytic viruses can stimulate the human immune system to find and destroy cancer, as well as make the body more receptive to other types of immunotherapy,” says City of Hope Research Center oncologist Daneng Lee, who is also the lead investigator on the project.

The success of the drug will primarily depend on data on how safe CF33-hNIS is in humans, so the first phase of trials will focus on this issue.