August 13, 2014 4:00 pm

What you need to know about Canada’s contribution to Ebola vaccines

WATCH ABOVE: Canada to donate experimental Ebola vaccines to help fight Ebola outbreak in West Africa 

TORONTO – ZMapp, VSV-EBOV, and TKM-Ebola. They’re a trio of experimental Ebola vaccines making waves in international news that also happen to have Canadian fingerprints all over their development.

As global health officials grapple with the world’s largest and longest Ebola outbreak in history, Canada is promising to donate 1,500 doses of its experimental therapy to West Africa.

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The Public Health Agency of Canada says the vaccine is a global resource – it’s hanging onto only a handful of doses to conduct small studies and as a backup should any Ebola cases arrive in Canada.

READ MORE: Canada to donate experimental Ebola vaccine to West African outbreak response

Coverage on the Ebola outbreak in Guinea, Nigeria, Liberia and Sierra Leone took a turn this week. Reports have surfaced about cultural disparities, hostility toward aid workers and suspected cases trickling into other countries, but the focus shifted to the ethics of doling out experimental drugs that haven’t been tested on humans.

By Tuesday, the World Health Organization said it’s ethical to use untested Ebola drugs and that countries that have potential treatments on hand have a “moral obligation” to collect data on those treated.

READ MORE: 5 things to know about the experimental Ebola drug

VSV-EBOV

Ottawa says it’s sending up to 1,000 doses of its vaccine that’s coming out of Winnipeg’s National Microbiology Laboratory. In this case, the federal government owns the intellectual property linked to the vaccine but licensed the rights to BioProtection Systems to further develop the product.

So far, it’s never been tested in humans, but it’s “shown promise” in animal trials. It’s still unclear how much of the vaccine is enough to protect its users, but for now, dosage is being determined based on the research done on primates.

Ten doses were already sent to a Geneva hospital as an emergency supply, according to The Canadian Press.

ZMapp

This therapy hit the headlines around the world after two American aid workers received the treatment with ties to Canada.

While the unlicensed treatment is made by California company Mapp Biopharmaceutical, it was produced with the help of Canadian research. Parts of the antibodies in the therapy are the product of years of research done at the Winnipeg lab.

“Canada is a world leader in research and we are proud of the advances made at the NML in this area,” a PHAC spokesperson told The Canadian Press via email.

READ MORE: Canadian research at core of experimental Ebola drug

Mapp Pharmaceutical president, Larry Zeitlin, told Global News that ZMapp is a collaboration between Mapp and Toronto-based Defyrus Inc. The U.S. government and the Public Health Agency of Canada were also involved, the company said.

Dr. Frank Plummer, who was head of the Winnipeg lab, said he was delighted to hear that the Canadian work helped pave the way for the ZMapp therapy.

“This is really gratifying to see the work come to fruition,” he told the wire service.

ZMapp is made up of three monoclonal antibodies, which are disease-fighting proteins that can target a specific part of an invading pathogen.

While reports refer to the treatment as a serum, Zeitlin clarified to Global: “Serum is a product derived from blood – human or animal. Monoclonal antibodies are protein drugs that are manufactured.”

The three portions of the antibodies include the components of MB-003 and ZMAb.

(PHAC told Global News that it helped to develop ZMapp but it wasn’t involved in any decision-making to administer the treatment. The federal agency developed two of the three components, licensed it to Defyrus, which in turn, sub-licensed it to Mapp. Mapp Pharmaceuticals, for its part, reformulated the treatment with another therapy created by the U.S. Army Medical Research Institute.)

The antibodies zero in on the Ebola virus, mark any foreign invaders and block out harmful cells. Reports say the drug is derived in part from tobacco plants.

The experimental drug was doled out to two people: Samaritan’s Purse physician Dr. Kent Brantly and his colleague Nancy Writebol, who was working with the organization Service in Mission.

READ MORE: Why health officials say the Ebola epidemic won’t spread into Canada

Right now, both patients are improving after taking the treatment but we won’t know for sure if it was the experimental therapy that saved them.

They could be recovering on their own, or for other reasons, such as receiving better medical care in the U.S.

A portion of the therapy – the MB-003 – provided 100 per cent protection to monkeys when it was administered right after exposure, according to researchers earlier this year.

The drug hasn’t been evaluated for safety in humans. Brantly and Writebol each had to give consent to using the drug, knowing that it’s only been tested on animals.

The trouble is, there is no more product left and it could take up to four months for another small batch of the drug to be made, a source told The Canadian Press.

TKM-Ebola

There are several Ebola vaccines making their way through the pipeline. When reports first surfaced that a single vial of a therapy made its way to Liberia, experts guessed that it could have been out of Vancouver’s own Tekmira Pharmaceuticals. (Ultimately, it was ZMapp.)

There, researchers are working on using small bits of genetic material called RNA to cling onto the virus and target it for destruction.

READ MORE: Canadian-made Ebola drug not used on U.S. missionary

The FDA had halted a small safety study with questions about a reaction in healthy volunteers. Last week, Tekmira announced that the FDA had modified its restriction, clearing a roadblock to possible experimental use in patients, and said it was “carefully evaluating options.”

- With files from the Canadian Press

carmen.chai@globalnews.ca

© Shaw Media, 2014

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