Researchers have discovered that a strain of the common cold virus could be lethal to cancer cells in the bladder.
We might not be any nearer to finding a cure for the common cold, but one particular strain of the virus could revolutionise treatment for bladder cancer. In a paper published to Clinical Cancer Research, researchers from the University of Surrey investigated the safety and tolerability of exposure to the cancer-killing virus coxsackievirus (CVA21) in 15 patients with non-muscle-invasive bladder cancer (NMIBC).
NMIBC is found in the tissue of the inner surface of the bladder, and in the UK alone approximately 10,000 people die each year with the illness. So far, existing treatments have posed a number of problems to the patients.
For example, transurethral resection – an invasive procedure to remove lesions – sees a high tumour recurrence rate of up to 70pc, with a high tumour progression rate of up to 20pc between two and five years after surgery. Meanwhile, immunotherapy with Bacille Calmette-Guérin, a live bacterium used to treat bladder cancer, has been found to have serious side effects in one-third of NMIBC patients while another third do not respond to the treatment at all.
Could ‘revolutionise treatment for this type of cancer’
As part of this study, the patients received a dose of CVA21 via a catheter in the bladder one week prior to surgery to remove tumours. Examinations afterwards showed the virus was highly selective, targeting only cancerous cells in the organ and leaving the rest intact.
It was shown that the virus replicated itself after infection of cancer cells, causing them to rupture and die. Urine samples taken from the patients also showed that after the cancer cells had died, the virus continued to attack cancerous cells in the organ.
Typically, bladder tumours don’t have immune cells to prevent a patient’s immune system from eliminating the cancer as it grows. Evidence suggests CVA21 inflames the tumour, resulting in immune cells rushing towards the cancer cells. This leads to ‘hot tumours’, which have been shown to be more likely targeted by immune cells than ‘cold tumours’.
Across the study, the majority of patients’ tumours showed cancer cell death, with one showing no case of cancer during surgery.
“Coxsackievirus could help revolutionise treatment for this type of cancer,” said Prof Hardev Pandha, principal investigator of the study.
“Reduction of tumour burden and increased cancer cell death was observed in all patients and removed all trace of the disease in one patient following just one week of treatment, showing its potential effectiveness. Notably, no significant side effects were observed in any patient.”