Avant, Harvard to develop cholera vaccine

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Avant, Harvard to develop cholera vaccine
July 18, 2005
By Steve Mitchell
United Press International
World Peace Herald
WASHINGTON -- The National Institutes of Health has awarded nearly $500,000 to Avant Immunotherapeutics and Harvard Medical School to develop a cholera vaccine that could help fight epidemics in developing countries and perhaps be useful for responding to bioterror attacks.

The vaccine will be based on Avant's VitriLife technology, which is intended to confer thermostability to live bacterial vaccines and enable them to be stored without refrigeration. The vaccine incorporated in the project will be Avant's CholeraGarde, which has shown promise in clinical trials, but is not yet licensed for use.
"Development of thermostable vaccines has been a priority for the NIH, the (World Health Organization) and the Bill and Melinda Gates Foundation," Una Ryan, Avant's president and chief executive officer, said in a statement.

"I am particularly pleased to see this project moving forward," said John Mekalanos, the inventor of the vaccine and a professor of microbiology and molecular genetics at Harvard.

"Thermostability of Avant's CholeraGarde is an important milestone to the development of an effective cholera vaccine for biodefense and global health purposes, settings where its use would be of the greatest urgency," added Mekalanos, who will co-direct the project.

Avant said the project will predominantly consist of optimizing manufacturing processes of the VitriLife technology, which is faster and cheaper than freeze-drying methods intended to preserve live bacterial specimens.

Although freeze-drying is an effective method of storage preparation, the main drawback is that freeze-dried vaccines are required to be stored at very cold temperatures to maintain stability and potency. Freezers or other methods of keeping the vaccine at these chilly temperatures are not always available in settings where the vaccine is most needed and could prohibit it from being readily available.

Formulations prepared using VitriLife technology and stored at room temperature have retained potency for up to a year, the company said.

The CholeraGarde vaccine "seems to be amendable to this manufacturing approach," Mekalanos told United Press International. He noted that batches produced with the VitriLife technology have been shown to be stable up to three months at the relatively hot temperature of 98.6 degrees Fahrenheit.

"This is quite a breakthrough and pretty much unheard of in the live bacterial vaccine field," Mekalanos said.

Once the manufacturing processes are worked out, the next step would be a limited study in U.S. volunteers, Mekalanos said. If that is successful, they would then plan on studies abroad, perhaps in Bangladesh, beginning sometime after the middle of 2006, he said.

Cholera is an infection caused by the bacterium Vibrio cholerae that generally is acquired via contaminated food or water. In about 20 percent of infected people, the bacterium causes intense diarrhea that can lead to dehydration and death.

Cholera outbreaks tend to occur in developing countries or situations where adequate sanitation is not available.

More than 400 people have been given the CholeraGarde vaccine in the United States and Bangladesh and it appears to be well-tolerated and provide complete protection against moderate and severe diarrhea due to the cholera bacteria, Avant said. The vaccine currently is in a Phase II trial in Bangladesh.