CIHR funded grant proposal "Efficacy evaluation of Ebola specific equine immune globulin (EEIg) against lethal Ebola virus (Zaire) in experimental models"

Principal Investigator: Darwyn Kobasa

Ebola virus is a pathogen that is endemic to a large portion of Africa. Since its discovery in 1976 it has been the cause of several significant outbreaks with mortality rates as high as 90%. While most of these outbreaks occurred in geographically isolated villages, the recent outbreak of Ebola virus in 3 countries in West Africa in 2014 resulted in 28,616 cases with 11,310 deaths and export of cases to multiple other countries. This event highlighted the capacity of this virus to cause a widespread epidemic. Vaccines for disease prevention as well as antibody and antiviral drug options for treatment are in development, although there is currently no medical countermeasure for Ebola virus yet approved for use in humans. We have evaluated a novel antibody based therapy developed by the US based company Integrated BioTherapeutics Inc. and Emergent BioSolutions. This is composed of an Ebola virus specific antibody preparation that is generated in horses given an Ebola virus vaccine and then processed and purified for use in infected individuals. Our initial evaluations have been done in mice and guinea pigs, which are animal models frequently used to evaluate vaccines and treatments for Ebola virus. The results of the studies indicate potent protection from disease in animals that have already been infected with the virus, showing protection of up to 100% of animals depending on the course of treatment. The results of these studies are currently being used for an experiment in a Rhesus Macaque model of infection as the final, most stringent, evaluation of the product.

Ebola virus is only one of several related members of a family of viruses called filoviruses that can cause severe disease and high rates of mortality in humans. Several of these viruses have caused large outbreaks in the past and all pose a significant threat for further outbreaks. A limitation of many vaccines and therapies for Ebola virus that are currently in development is that they will not work or will work poorly against these other viruses. Antibody therapeutics on the equine platform are in development to address a broader range of filoviruses including Ebola, Marburg and Sudan.  The strength of the equine platform for development of an antibody treatment is that it can be rapidly implemented and scaled up for any of these viruses or even a previously unknown virus. Therefore, the current studies are supportive of the potential value of the existing product for treatment of Ebola virus and also the equine antibody platform for responding to any future outbreak of a highly contagious and virulent virus for which no treatment already exists.

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