The US Food and Drug Administration (FDA) have approved an innovative drug that uses the herpes virus to selectively attack skin cancer tumours (melanomas).
The virus is a injected straight into the tumour. It has been genetically modified, with the gene changes allowing it to specifically target and kill cancerous cells. The virus invades both cancerous and healthy cells, but it is unable to replicate in healthy cells and thus they remain unaffected. Inside a cancer cell, the virus is able to replicate, producing proteins which stimulate the immune system to attack the cancer cells.
“Melanoma is a serious disease that can advance and spread to other parts of the body, where it becomes difficult to treat,” stated Karen Midthun, director of the FDA’s Centre for Biologics Evaluation and Research. “This approval provides patients and health care providers with a novel treatment.”
The most common side effects observed included nausea, flu-like symptoms and pain at the injection site. However, because the virus only targets cancerous cells, side effects compared to non-selective treatments like chemotherapy are greatly reduced.
Prof Kevin Harrington, from the Institute of Cancer Research, London, said: “Because viral treatment can target cancer cells specifically, it tends to have fewer side effects than traditional chemotherapy or some of the other new immunotherapies.”
Studies showed that just over 16 per cent of patients injected with the drug saw their tumours shrink. While this does not sound like a large amount, it is a step up from the two per cent of patients who took conventional cancer drugs.
The approval of the the drug is also regarded as a significant first-step in creating selective cancer treatments, but it is still early days. Dr Stephen Russell, a researcher who specialises in treating cancer with viruses, concurs: “We can’t prematurely claim that we’ve achieved our ultimate goal, because we haven’t; this really is a single step along that path,” he said. “But it’s a very important and very significant step.”
In the UK, skin cancer is the fifth most common cancer. It was responsible for the deaths of 2,148 individuals in 2012. While there have been recent clinical trials in the UK, the treatment is not yet licensed.