Scientists at The Institute of Cancer Research, London, tested the effectiveness of a genetically engineered version of the virus used to vaccinate against smallpox. They found use of the virus alongside isolated limb perfusion chemotherapy – given directly to blood vessels supplying the affected arm or leg as an alternative to amputation – was more effective in rats than either treatment on its own.
The study, published in the International Journal of Cancer, was funded by the Dr Lucy M Bull Lectureship and Research Fund and supported by the NIHR Biomedical Research Centre at The Royal Marsden NHS Foundation Trust and The Institute of Cancer Research (ICR), with additional funding from The Royal College of Surgeons of England and Sarcoma UK.
Researchers at the ICR, in collaboration with colleagues at The Royal Marsden, used a vaccinia virus known as GLV-1h68. This virus had been modified to infect and kill cancer cells.
The study suggests that the combination, if successful in the clinic, could help some skin cancer and sarcoma patients avoid radical surgery or amputation, greatly improving their quality of life. A clinical trial to test the combination in cancer patients has now been approved and is expected to take place in the near future.
Isolated limb perfusion uses a heart and lung bypass machine connected to the arm or leg to separate its blood supply from the rest of the body. This allows a high dose of a chemotherapy drug (in this case melphalan) to be given directly and specifically to the diseased limb without causing toxic side-effects to the rest of the body.
Chemotherapy is given alongside a drug called tumour necrosis factor-alpha (TNF-α) which helps make blood vessels more leaky, allowing melphalan to get to the tumour more effectively. In this study, researchers found that TNF- α also helped the virus get to the tumour more easily.