Emergent BioSolutions says typhoid vaccine candidate shows promise

ROCKVILLE, Md. — Emergent BioSolutions Inc. announced Jan. 8, 2008, that the final analysis from a recently completed, randomized, placebo-controlled, blinded Phase II clinical study reaffirmed that its single-dose, drinkable typhoid vaccine candidate was highly immunogenic and well-tolerated with an acceptable safety profile in the population studied.

For the study, 151 Vietnamese children from 5 to 14 years old were enrolled. A total of 101 children received the vaccine candidate and 50 children received a placebo. This clinical study is the first trial involving a pediatric population and was performed in collaboration with the Wellcome Trust, Oxford University and the Hospital for Tropical Diseases in Ho Chi Minh City, Vietnam.

The results showed that 97 percent of the children dosed developed an immune response, which was defined as an increase in Salmonella typhi LPS-specific IgG antibody levels and/or Salmonella typhi LPS-specific IgA antibody levels in the blood, suggestive of systemic and mucosal protective immunity, respectively. This represented a statistically significant difference from the placebo group.

Also, 93 percent of the children developed responses as measured by increases in Salmonella typhi LPS-specific IgG antibody levels suggestive of systemic protective immunity and 94 percent developed an immune response as measured by increase in Salmonella typhi LPS-specific IgA antibody levels suggestive of mucosal protective immunity.

There were no safety concerns following administration of a single dose of the drinkable typhoid vaccine candidate. The proportion of subjects reporting adverse events was similar for the vaccinated group (26 percent) and the placebo group (22 percent); this difference was not statistically significant.

There were no serious adverse events reported, no deaths and no subjects withdrew because of adverse events. There were small differences in specific adverse events with more gastrointestinal symptoms and headaches reported in the vaccinated group and more respiratory symptoms in the placebo group.

“A Phase II trial in the United States and a Phase IIb trial in an endemic population are both slated to begin by the end of 2008,” said Fuad El-Hibri, chairman and CEO of Emergent BioSolutions. “Both of these trials will use clinical material produced using a scaled-up commercial manufacturing process.”