Experimental Drug Protects Against Virus Similar to Ebola

Promising treatment protects nonhuman primates from Marburg virus up to 3 days after infection.

An experimental treatment from Tekmira Pharmaceuticals Corp is highly effective in protecting monkeys from a virus related to Ebola hemorrhagic fever, according to the results of a study published Wednesday in Science Transitional Medicine.

Researchers evaluated Tekmira’s lipid nanoparticle (LNP) technology using an animal model of the Marburg virus infection. The study authors relied on an anti-Marburg nucleoprotein that targets small interfering RNA at several points following exposure to the virus, including after the onset of detectable disease in nonhuman primates.

In the trial, 21 rhesus monkeys were given a lethal dose of the virus, and 16 of those primates received the LNP treatment at 30 to 45 minutes, 1 day, 2 days, or 3 days after infection. All of the monkeys that received the treatment survived the infection, while the untreated and mock-treated control animals died between 7 and 9 days after being infected.

"These positive findings build upon our extensive work in antiviral RNAi therapeutics and provide further validation of our strong LNP product platform, which includes RNAi therapeutics addressing chronic hepatitis B infection and lethal hemorrhagic fever viruses," said Mark Murray, PhD, president and CEO of Tekmira, in a press release.

Tekmira is also developing a separate Ebola treatment called TKM-Ebola that acts similarly to the LNP-utilizing RNA interference. That treatment was placed under a clinical hold by the FDA on July 3, 2014, but that hold was lifted on August 7, 2014, allowing the company to proceed with the early stages of human testing.

The World Health Organization yesterday updated the Ebola-related death toll to more than 1350 people, with more than 2000 confirmed and suspected cases.

While Tekmira’s experimental treatment has shown promise in animal testing, the use of ZMapp from Mapp Biopharmaceutical, Inc, may have played a role in saving the lives of 2 American relief workers who became infected while working with patients in Liberia.

It was announced today that Dr. Kent Brantly and Nancy Writebol would be discharged from Emory University Hospital following specialized treatment after they were airlifted from West Africa. However, it remains unclear how much of an impact ZMapp played in their recovery.

"If the question is, 'Did Zmapp do this?' The answer is that we just don't know," Anthony Fauci, director of the National Institute of Allergy and Infectious Disease, told USA Today. "People who are in much less sophisticated medical care conditions in West Africa are recovering 50% of the time."

Elsewhere, a patient admitted on Tuesday to Kaiser Permanente South Sacramento Medical Center in California who may have been exposed to Ebola was deemed “low risk” for the virus after being evaluated for the various risk factors and symptoms of acquiring the disease, according to a report in USA Today.

"Taking all those criteria into account, we have determined this patient is low risk," James Watt, chief of the Division of Communicable Disease Control at the Center for Infectious Diseases, said in the report.