The formal presentation of the results is scheduled for Sunday, at the 32nd EORTC-NCI-AACR Symposium on cancer therapy, to be held in Barcelona and which due to the covid-19 pandemic will take place virtually over the weekend.
The vaccine was created to target a gene called KRAS, which is related to the development of many types of cancer, including those of the lung, intestine and pancreas.
The vaccine study was conducted by Rachel Ambler, a postdoctoral researcher, and other researchers at the Francis Crick Institute.
“We know that if the KRAS gene fails, it prevents cells from multiplying and becoming cancerous. More recently, we learned that, with the right help, the immune system may be able to slow this process down, ”said Ambler in a statement released by the congress organization.
“We wanted to see if we could use this knowledge to create a cancer vaccine that could be used not only to treat it, but also to provide lasting protection against the disease and with minimal side effects,” added the expert.
The researchers have created a set of vaccines that can elicit an immune response against most of the most common KRAS mutations.
Vaccines are made up of two united elements, a fragment of the protein produced by cancer cells that have the mutated KRAS gene and an antibody that helps the vaccine reach a type of immune system cell called dendritic, which helps the system to destroy cancer cells, a capacity that vaccines can enhance.
The researchers tested the vaccine in mice that had lung tumors and in others that had tumor growth induced.
They studied the mice to see if their immune systems responded to the vaccine, and they also looked at whether the tumors reduced or didn’t even form.
In animals with tumors, about 65% of those treated with the vaccine remained alive 75 days later, compared with 15% of those who had not received it.
In rats treated to induce tumors, about 40% of vaccinees remained tumor-free 150 days later, compared with only 5% of those not vaccinated.
By vaccinating the mice, the researchers found that tumor growth was delayed by an average of 40 days.
“When we used the vaccine as a treatment, we saw that it slowed the growth of tumors in mice. And when we used it as a preventive measure, we saw that tumors did not appear for a long time and that, in many cases, they never appeared at all, ”summarized Ambler.
Some previous cancer vaccine trials have failed, according to the researcher, because they have not been able to create a sufficiently strong immune system response that could reach and destroy cancer cells.
“This research has a long way to go before it can help prevent and treat cancer in people, but our results suggest that the development of the vaccine has created a strong response in mice, with very few side effects,” he concluded.