A variant of the common cold virus has shown promising trial results as a treatment for bladder cancer.

Bladder cancer is the tenth highest incident cancer in the UK and kills approximately 5,300 people a year. Current treatments for bladder cancer mostly have high recurrence rates or dangerous side-effects.

15 non-muscle invasive bladder cancer patients took part in the trial. The common cold virus coxsackievirus (CVA21) was administered to patients through their catheters, one week before surgery to remove their tumours. After surgery, the tumours were examined. All patients showed reduction in tumour burden and increased death of cancer cells. In one patient, no trace of cancer could be found. The virus was also shown to selectively target the cancer cells over normal body cells.

The selectivity that viruses show to cancer cell has been behind their increasing success as cancer treatments. Due to the higher proliferation rate of cancer cells, viruses will preferentially use them to replicate in, which kills the host cell. Viruses also have the potential to be genetically engineered to increase their selectivity even more. Past successful methods have included engineering viruses to show greater affinity for receptors characteristic of cancer cells.

This is of extra important to bladder cancer. Typically, there are few immune cells present around the bladder area, which in other cancers can either control tumour growth or eliminate it. Scientists have recently managed to engineer viruses to initiate an inflammatory response to make immune cells to migrate to the cancer environment.

The successful trial for bladder cancer is another step forward in research to develop viruses into effective cancer cures.