A groundbreaking study reveals that a bacteria-killing virus can selectively destroy cancer cells in mice. By harnessing the immunity generated from vaccination, researchers redirected the immune response to effectively target and eradicate tumors. In trials, nearly 50% of vaccinated mice infected with a harmless phage demonstrated tumor disappearance.

Immunotherapy has revolutionized cancer treatment, but many still struggle to benefit due to challenges in immune system recognition of tumors. The latest research aims to enhance this recognition.

Researchers led by Amin Hajitou at Imperial College London investigated phages that infect Escherichia coli. Upon infecting the bacteria, these phages inject genetic material, reprogramming the bacterial machinery to generate numerous new phages that effectively eradicate these pathogens.

To improve targeting, the team genetically engineered the phages to recognize proteins called αvβ3 and αvβ5 integrins, which are prevalent in many tumor cells but are scarce in healthy tissues. Additionally, they modified the phage’s genetic payload to include malaria-specific antigens to stimulate a robust immune response. “Phages serve as precision delivery vehicles for our interventions,” states Hajitou.

The researchers conducted tests on 60 mice with tumors positioned under the skin. A subset received a malaria vaccine, followed by phage injections in the tail over two weeks. Control groups included those receiving no treatment, only the vaccine, or only the engineered phage.

Results showed that tumors vanished in 44% of treated mice, and notably, these tumors did not recur a year post-study. Additionally, treated mice exhibited increased lifespans compared to their untreated counterparts, though no significant survival advantage was observed.

“This innovative approach allows engineered viruses to systematically target tumor cells,” remarks David Withers from Oxford University. “This capability markedly enhances current strategies for manipulating tumors, such as using oncolytic viruses, which are limited by the need for direct administration into cancer sites.”

With further adjustments to the phage’s antigen-producing capabilities, the technique may also apply to humans vaccinated against diseases like seasonal influenza and COVID-19. “Utilizing more effective vaccines than malaria could amplify our results,” Hajitou explains. “This strategy leverages pre-existing immune memory and is not confined to malaria alone.”

The research team is currently in discussions with the UK’s Medicines and Healthcare products Regulatory Agency (MHRA) to initiate early-stage human trials as soon as next year.