Drugs protect monkeys from Ebola, U.S. study finds

WASHINGTON (Reuters) - U.S. government researchers working to find ways to treat the highly deadly Ebola virus said on Sunday a new approach from AVI BioPharma Inc saved monkeys after they were infected.

Two experimental treatments protected more than 60 percent of monkeys infected with Ebola and all the monkeys infected with a related virus called Marburg, the team at the U.S. Army Medical Research Institute of Infectious Diseases (USAMRIID) in Fort Detrick, Maryland reported.

AVI BioPharma already has a contract worth up to $291 million from the U.S. Department of Defense to develop Ebola treatments.

Writing in the journal Nature Medicine, Sina Bavari and colleagues said the drugs tested are antisense phosphorodiamidate morpholino oligomers, or PMOs, called AVI-6002 and AVI-6003.

"Taken together, these studies provide a major advancement in therapeutic development efforts for treatment of filovirus hemorrhagic fever," Bavari's team wrote.

The company has submitted investigational new drug applications for AVI-6002 and AVI-6003 to the U.S. Food and Drug Administration and may now test the drugs in people.

Ebola triggers a very serious fever with bleeding that has caused dozens of frightening and deadly outbreaks across Africa and threaten endangered gorilla populations as well as people.

It is considered a possible bioterrorism weapon.

There is no treatment and no vaccine against Ebola, which passes via close personal contact and, depending on the strain, kills up to 90 percent of victims.

But several studies in the past few months have shown that experimental "antisense" therapies can stop the virus.

In May a U.S. government team reported that small interfering RNAs or siRNAs could hold the virus at bay for a week until the immune system could take over.

SiRNAs are little stretches of genetic material that can block the action of a specific gene, in this case preventing Ebola from replicating.

PMOs are a little different but also interfere with genes.

An hour after infection with Ebola, the researchers started to treat the animals, continuing for either 10 or 14 days. After 28 days, 5 of 8 monkeys survived.

AVI-6003 worked best, protecting 90 percent or more of monkeys against Ebola, they said, and 100 percent against Marburg.

Canada's Tekmira Pharmaceuticals Corp has a separate contract to develop antisense treatments against Ebola.

SOURCE: link.reuters.com/qyp66n Nature Medicine, online August 22, 2010.