Monkeys Cured of Ebola Zaire Virus With Antibody Cocktail

Ebola virus under the microscope.

A cocktail of three antibodies has been able to cure monkeys infected with the Ebola virus if administered 24 hours or more after exposure. This could imply that a future treatment for humans could be possible. Some of the variants of the Ebola virus kill up to 90% of infected patients, and currently, most treatment regimens only improve survival when administered within an hour of infection.

Researchers from the National Microbiology Laboratory in Winnipeg, Canada, published their findings in the journal Science Translational Medicines. The new cocktail is named ZMAb and was administered to cynomolgus monkeys (Macaca fascicularis) who were infected by the Ebola Zaire virus, the deadliest strain of Ebola which is still prevalent in the Congo and Gabon. The monkeys began their treatment within 24 hours of being infected and all three survived. Two of four monkeys given the cocktail within 48 hours of infection also survived. Untreated monkeys died within five days of being exposed to Ebola Zaire.

The antibodies slowed the replication of the virus until the animals’ own immune systems kicked in and cleared the virus, states Gary Kobinger, a medical microbiologist at the University of Manitoba and lead author. The antibodies, obtained from mice vaccinated with fragments of the virus, target and neutralize a glycoprotein on the surface of the Ebola virus that allows it to enter and infect cells.

This strategy isn’t new, but this cocktail contains multiple antibodies that target different locations of the glycoprotein, making it harder for the virus to resist it. Defyrus, a biotech company based in Toronto, Canada, is developing the antibodies as part of their Ebola treatment called Defilovir, which works in tandem with DEF201, an antiviral gene therapy. They plan on entering phase I clinical trials before the end of 2014.

Reference: “Successful Treatment of Ebola Virus–Infected Cynomolgus Macaques with Monoclonal Antibodies” by Xiangguo Qiu, Jonathan Audet, Gary Wong, Stephane Pillet, Alexander Bello, Teresa Cabral, Jim E. Strong, Frank Plummer, Cindy R. Corbett, Judie B. Alimonti and Gary P. Kobinger, 13 June 2012, Science Translational Medicines.
DOI: 10.1126/scitranslmed.3003876