Emergent BioSolutions' typhoid vaccine achieves positive results in clinical study

GAITHERSBURG, Md. — Emergent BioSolutions on Aug. 30, 2005, announced positive results from a Phase II clinical study evaluating a simplified dosing regimen for the company’s next-generation single-dose oral typhoid vaccine. The results of the study were published in the August 2005 edition of the Journal of Infectious Diseases.

The Phase II study, led by Dr. Beth D. Kirkpatrick at the University of Vermont, evaluated the safety and immunogenicity of the vaccine in 32 healthy adult volunteers. The study demonstrated that the use of a simpler, more rapid dosing regimen did not affect the safety profile or the magnitude of the immune response stimulated by the vaccine.

Previously, a single dose of the oral typhoid vaccine was shown to be safe, well tolerated and highly immunogenic in human volunteers when using a lyophilised product suitable for commercialization. However in previous studies subjects were required to be pre-dosed with a bicarbonate buffer and the vaccine strain was reconstituted in bottled water prior to administration.

The improved regimen tested in the Phase II study removes the requirement for pre-dosing with bicarbonate buffer and the vaccine is administered immediately following reconstitution in tap water.

 In the current trial, 16 subjects received the vaccine using the old regimen and another 16 subjects received the vaccine using the rapid dosing schedule. In both groups the vaccine was well tolerated. All volunteers mounted an immune response to the vaccine after a single dose, demonstrated by measuring mucosal and systemic antibody responses. There was no significant difference in the magnitude of the response between the two groups.

“We think this oral, single-dose freeze-dried vaccine, which was simple to administer, is showing great promise providing an excellent basis on which to advance further clinical development,” Kirkpatrick said. “A single oral-dose typhoid vaccine which is simple to administer would facilitate vaccination in all populations, including travelers to, and residents living in, areas where typhoid fever is endemic or epidemic."

Emergent BioSolutions is planning to evaluate its oral typhoid vaccine further in Phase II studies in Vietnam with financial support from the Wellcome Trust prior to starting Phase III studies.

Emergent BioSolutions Inc., formed in 2004, is dedicated to the research, development and manufacture of products that harness the immune system to treat and prevent disease. These include vaccines and related products for prophylactic and therapeutic use against common infectious diseases and biological weapons of mass destruction.