Vaccine developed by Canadian government could be mass produced within months.
While the Ebola-related death toll in West Africa continues to rise, drug manufacturers are stepping up their efforts to advance experimental treatments for the disease into the clinical trial phase.
A vaccine called VSV-EBOV that was developed by the Government of Canada and licensed for further development to American firm NewLink Genetics Corp through subsidiary BioProtection Systems Corp has shown promise in animal testing, but it has yet to be used in humans. Earlier this week, Canada announced it will donate up to 1000 doses of VSV-EBOV
to the World Health Organization (WHO) to aid in halting the spread of the virus, which has killed more than 1000 people, with more than 1800 confirmed and suspected cases.
Last week, BioProtection Systems received a $1 million contract with the US Defense Threat Reduction Agency (DTRA) for studies on the vaccine to bring it closer to human clinical trials.
“There is an urgent need for a medical countermeasure against the deadly Ebola virus,” said Charles Link, MD, chairman and chief executive officer of NewLink in a press release
. “This Ebola vaccine has been 100% effective in preventing lethal infection when given to non-human primates before they are infected with the virus. The vaccine also acts rapidly enough to have significant efficacy even when given to animals that have recently received a typically lethal dose of Ebola virus.”
Dr. Link told Reuters
that NewLink will be able to produce tens of thousands of doses for the drug within the next 2 months.
Efforts to develop a vaccine were accelerated following the decision by a WHO ethical panel
that there is a moral obligation to use experimental treatments on patients in the disease-ravaged region. Two companies that are also receiving funding from the DTRA have promising Ebola treatment candidates in early development.
A drug by BioCryst Pharmaceuticals, called BCX4430, has exhibited the potential to treat a broad spectrum of activity in multiple viruses with a favorable preliminary safety profile. The drug has shown efficacy in a small study of nonhuman primates, but has yet to be evaluated in humans.
A treatment from Tekmira Pharmaceuticals Corp, called TKM-Ebola, had an FDA phase I clinical hold changed to a partial hold
on August 7, 2014, which will allow for testing in humans.
A third drug, ZMapp, showed promising results
in treating infected American aid workers Dr. Kent Brantly and Nancy Writebol, who showed signs of recovery after receiving the treatment. However, supplies of ZMapp have now been exhausted. Director of the National Institute of Allergy and Infectious Diseases Anthony Fauci, MD, wrote in an essay in the New England Journal of Medicine
on Wednesday that production of ZMapp has been scaled up, but he added that the process would take time.
Despite the dire need, objections have been raised in the American medical community about the potential dire consequences of using untested treatments in human patients.
“To use this drug without having any information on its human benefits or dangers runs the risk of mistakenly thinking it is either effective or not based upon anecdotal evidence, a difficulty that could prove disastrous for later in this outbreak or future ones,” said Philip M. Rosoff, MD, director of the Clinical Ethics Program at Duke University Hospital, in a press release. “Desperately sick people and their families make decisions under very trying circumstances. Often, they are willing to try anything that they believe—or can be led to believe—may offer some hope of improvement or a cure. As such, they can be ripe targets for those who would take advantage of their desperation and plight. Thus, extra caution and thought must be given to using experimental and possibly dangerous treatments in this population.”