Synthetic horsepox virus raises hopes for improved smallpox and cancer treatments

19th January 2018 (Last Updated January 19th, 2018 19:01)

Synthetic horsepox virus raises hopes for improved smallpox and cancer treatments
David Evans and Ryan Noyce have engineered a synthetic horsepox virus. Credit: Melissa Fabrizio

Researchers from the University of Alberta have created a synthetic virus that could “revolutionise how we manufacture complex biologicals”, according to virologist and breakthrough leader David Evans.

In a study published today in PLOS ONE, Evans and research associate Ryan Noyce reported the production and testing of a horsepox virus, engineered entirely through chemical methods. Horsepox does not pose a threat to humans, but is closely related to the vaccinia virus, which was used as part of the vaccine to eradicate smallpox 40 years ago.

Despite the disease’s eradication, smallpox vaccines are still a necessity for many; in the wake of the September 11 attacks, the US Department of health and Human Services recommended that half a million healthcare and emergency workers receive the vaccination due to the potential threat of smallpox as a biological weapon.

Additionally, the WHO maintains a stockpile of 33.41 million doses of the vaccine, in both their Swiss headquarters and in donor countries around the world, to be used in emergencies.

Yet these vaccines pose dangers themselves. A 2016 New Zealand study involving testing existing smallpox vaccines on rabbits reported that there was a “repeated high-dose” of toxicity in vaccinated rabbis, and the WHO reported in 2009 that “potentially life-threatening reactions” were observed in between 24 and 52 people per million people vaccinated.

Critically, the WHO estimates that between one and two people out of every million people vaccinated may die “as a result of life-threatening reactions to the vaccine”.
Since Evans and Noyce’s breakthrough, New York-based Tonix Pharmaceuticals has begun to develop the synthetic horsepox in such a way that an effective and safe smallpox vaccine can be produced.

“Tonix’s goal is to develop a vaccine that has a better safety profile than the current vaccines for broader usage and to provide greater protection to the public”, said Seth Lederman, president and CEO of Tonix.

Evans and Noyce’s work may also influence cancer treatments. The vaccinia virus is an oncolytic virus, defined as one that can “selectively replicate in and kill cancer cells without harming the normal tissues” in ‘Oncolytic virus therapy: A new era of cancer treatment at dawn’. The report, published in 2016 in the National Center for Biotechnology Information, was authored by Hiroshi Fukuhara, Yasushi Ino and Tomoki Todo.

However, the complexities of these viruses, and the cancers they are intended to treat, means their use is not without risk. Fukuhara, Ino and Todo concluded that the delivery methods of oncolytic viruses are not consistently effective, and there are questions surrounding their effectiveness when not used alongside other similar treatments.

In ‘Oncolytic Viruses – Genetically Engineering the Future of Cancer Therapy’, a report published in Frontiers in 2017, Benjamin Gesundheit and Joshua P. Rosenzweig wrote that there are “additional research challenges” involved in these treatments.

Evans, meanwhile, is eager to develop oncolytic-based treatments further. “We have had considerable interest from people interested in producing vaccines against animal poxvirus diseases, as well as in using vaccinia virus as a vector for other vaccines,” he said.