A groundbreaking study reveals that bacteriophages, viruses that target bacteria, can help in eliminating cancer cells by reorienting the immune response established through vaccination. In experiments involving mice vaccinated against malaria, a harmless phage was utilized to target and eradicate tumors, achieving success in nearly 44% of the subjects.

Immunotherapy has revolutionized cancer treatments, yet many patients do not reap its benefits due to the challenge of getting the immune system to identify tumors as threats. To address this,
Amin Hajitou and his team from Imperial College London investigated phages that specifically infect
Escherichia coli. These phages attach to bacteria, inject their genetic material, and replicate, thereby destroying the bacterial cells.

The research team engineered the phages to specifically target proteins known as αvβ3 and αvβ5 integrins, which are prevalent in tumor cells but scarce in healthy cells. Additionally, they customized the phages to produce malaria-specific antigens—signals that prompt the immune system to recognize them as foreign invaders. “Phages function as targeted delivery vehicles,” explains Hajitou.

The efficacy of this approach was tested on 60 mice with subcutaneous tumors. Among them, 15 mice received a malaria vaccine followed by injections of engineered phages at two-week intervals. The control group consisted of 15 mice each receiving no treatment, the malaria vaccine only, or the engineered phage exclusively.

The results revealed that tumors disappeared in 44% of the treated mice, with no recurrence observed a year post-study. Although the treated mice exhibited longer lifespans compared to controls, a survival advantage was not significantly noted.

According to
David Withers at Oxford University, “These engineered viruses can target and infect tumor cells systemically.” This strategy marks a significant advancement over current methods of manipulating tumors, such as oncolytic viruses, which necessitate direct injections at cancer sites—an impractical method especially for metastatic diseases.

By fine-tuning the phage’s antigen-producing capabilities, this innovative approach could also extend its effectiveness to individuals vaccinated against other infectious diseases like seasonal influenza and COVID-19, showcasing the versatility of this method. Hajitou asserts, “More potent vaccines than malaria are likely to yield even greater results.” The aim is to leverage existing immune memory without being limited to malaria-specific responses.

The research team is currently engaging with the UK’s Medicines and Healthcare products Regulatory Agency (MHRA) to explore the possibility of commencing early-stage human trials next year.