UW-Madison: Ebola vaccine clinical trial in Japan

MADISON – As of this week, a phase one clinical trial to test a potential new Ebola vaccine developed by researchers at the University of Wisconsin-Madison is underway in Japan.

Fifteen healthy young men* will receive two doses of the experimental vaccine. If the first group tolerates the vaccine, an additional group of up to 20 volunteers will receive a higher dose of the vaccine.

“In phase one, the main goal is safety,” says Yoshihiro Kawaoka, professor of pathobiological sciences at the UW-Madison School of Veterinary Medicine, who, with Peter Halfmann, a research associate professor in his lab, created the new vaccine.

The researchers will also measure whether the immune systems of the trial participants begin to mount protective responses by developing antibodies and an immune memory for the virus after receiving the vaccine. The phase one trial will not involve exposing subjects to Ebola virus.

Unlike other experimental vaccines, the vaccine created by Kawaoka and Halfmann does not rely on a secondary, live-though-weakened virus to deliver a portion of the Ebola virus to the human immune system. In fact, the new experimental vaccine is made from the whole Ebola virus, save for one gene that renders the virus in the vaccine noninfectious.

“Our vaccine contains everything except one small protein,” says Kawaoka, also a professor of virology at the University of Tokyo. “It has more antigens to elicit protection and it’s an inactivated virus, so it’s safer.”

Since more of the virus proteins are present in this vaccine relative to others, it also improves the chances the immune system develops a robust capacity to fight Ebola virus if a person is exposed.

The form of Ebola virus contained in the vaccine is a technology Halfmann created more than a decade ago, called DeltaVP30. The technology renders the virus incapable of reproducing itself because it eliminates a gene that makes a protein critical for this task. The virus can only grow in a special cellular system containing the missing protein, which is not found in human or animal cells. Prior to use in humans, it was proven safe and effective in mice, guinea pigs, and in non-human primates.

*The current phase one clinical trial does not involve women in order to avoid subjects who may be pregnant.