Treating bladder cancer with an engineered virus

New funding will help bring the therapy one step closer to clinical use

Shelby Soke - 29 March 2017

Viruses are commonly associated with illness. Whether it is a nasty stomach bug or a bout of influenza, most people do not equate introducing a virus to the body with positive outcomes. David Evans, professor and vice-dean of research at the Faculty of Medicine & Dentistry, is not like most people-he sees viruses as a potential cancer-fighting treatment.

Evans aims to use a virus he engineered to improve the treatment of non-muscle invasive bladder cancer (NMIBC). The virus is an oncolytic virus, which means it has been modified to selectively kill rapidly-dividing cancer cells while remaining safe for surrounding healthy cells.

Bladder cancer is the sixth most common cancer in Canada. Currently NMICB is treated surgically; surgeons remove the cancer by cutting it or scraping it out of the bladder. Chemotherapy, and/or intravesical administration of Bacillus Calmette-Guerin (BCG), a vaccine used for tuberculosis, may also be used.

Unfortunately, there is a high rate of recurrence of NMICB. Patients need to be monitored frequently and, if the cancer returns, treatment becomes increasingly more aggressive.

"There's an unmet need," says Evans. "We really need better ways to treat this disease; we got a clue from the use of the pro-inflammatory BCG vaccine, that a virus could be used as a form of treatment."

Evans's team has shown that the virus works well in pre-clinical models. The lab rats he is using develop immunity to the tumour cells when the virus infects and kills these cells, which prevents the cancer cells from reoccurring.

"The virus can be delivered directly to the bladder without spreading to other tissue," says Evans. "The other advantage of this virus we have observed is that tumours that are resistant to BCG can still be sensitive to the virus because it gets in by a different mechanism."

Evans has collaborated with cancer researchers Mary Hitt from the Department of Oncology and Ron Moore from the Department of Surgery.

The research recently received a funding boost from BioCanRX in partnership with Alberta Innovates and the Applied Virology project, that will help them take the project to clinical trials.

The next steps are producing a clinical-grade virus and preparing the application for the clinical trial, which is very labour intensive.

Evans's proposal is different from previous uses of oncolytic viruses. While most oncolytic viruses are used as a "last chance" for people who have more advanced disease and have used other available options, the team is proposing to go in early. They believe the virus is very safe because of its mutations and that patients would benefit most from early intervention.

"I've been very impressed by the support for this work at the University of Alberta," says Evans. "The Northern Alberta Clinical Trials and Research Centre and the Cross Cancer Institute Clinical Trials group have done everything they can to get this accomplished. Long-term support from agencies such as the Canadian Institutes of Health Research is what led us to developing this virus, which wouldn't happen without basic science research funding."