They are designed to make a patient’s immune system attack tumours
Personalised cancer vaccines that target people’s individual tumours have shown early signs of promise in tests on three patients diagnosed with advanced skin cancer.
The vaccines were designed to make the patients’ immune systems unleash attacks on specific DNA mutations in their tumours, and so turn the body’s natural defences against the disease.
The approach, tested for the first time on people at Washington University School of Medicine in St. Louis, found that the vaccines caused the patients to launch powerful immune reactions against the tumours.
Though promising so far, the research is at a very early stage, and the researchers cannot yet say whether the patients’ health improved after the treatment. All three are stable and suffered no side effects, but further trials are needed to see whether the treatment can help to shrink or even eradicate tumours.
“These custom-designed vaccines can elicit a very strong immune response,” said Gerald Linette, a cancer specialist leading the trial. Blood tests on patients who had the treatment revealed that their immune systems had produced waves of killer T-cells that can destroy tumours. “Our results are preliminary, but we think the vaccines have therapeutic potential based on the breadth and remarkable diversity of the T-cell response,” Linette added.
The vaccines were created by first comparing the genomes of the patients’ tumours with their healthy tissue to identify mutated proteins called neoantigens that were unique to their tumour cells. The scientists then used computer models and lab tests to work out which neoantigens were most likely to provoke the most powerful immune response.
The researchers used the list of neoantigens to make bespoke vaccines for each patient. They selected seven neoantigens for each, and embedded them into specialised immune cells called dendritic cells. When infused into patients, these dendritic cells act like biological wanted posters, telling the immune system what to look for and attack.
