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Emergent Biosolutions' Typhoid Vaccine Achieves Positive Results in Phase II Clinical Study

Posted on: Tuesday, 30 August 2005, 09:00 CDT

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

The Phase II study, conducted under a company-sponsored IND 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 utilization of a simpler more rapid dosing regimen did not affect the excellent 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 announced today is a more rapid, commercially attractive formulation in that it 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 improved 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. This important result demonstrates that the vaccine can prime both the mucosal immune system, the body's first line of defense, as well as the systemic immune system, when administered using the improved dosing regimen. This is essential for a successful single dose approach. Injected vaccines generally elicit a systemic response but a poor mucosal immune response.

Commenting on the results, investigator Dr. Beth Kirkpatrick said, "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. 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."

"These latest clinical results are very encouraging," said Dr. Steven Chatfield, Emergent's Chief Scientific Officer. "The fact that the vaccine was produced using a commercially viable manufacturing process coupled with a simple dosing regimen vaccine will greatly facilitate further clinical development leading to a Phase III program."

Emergent 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 used its patented Signature Tagged Mutagenesis (STM) functional genomics technology -- which allows the development of safe live attenuated vaccines -- to develop this new vaccine. The results of this clinical study further validate the approach of using the oral typhoid vaccine to orally deliver other vaccine antigens for delivery to the immune system. The company has already developed a vaccine against a common form of traveler's diarrhea (ETEC), and a therapeutic vaccine to treat chronic Hepatitis B carriers based on this approach. Both vaccines have been evaluated in Phase I clinical trials and were shown to be safe and immunogenic. Other conditions that could be prevented, or treated, are also being investigated and include bacterial and viral diseases, allergies and cancer.

TYPHOID OVERVIEW

The Incidence - A significant number of cases of typhoid are reported in both Europe and US most of which are contracted while abroad with an estimated global incidence of 30 million cases and 600,000 mortalities, worldwide every year. It is estimated that many millions of travelers from the United States and the United Kingdom visit typhoid high-risk areas annually. The U.S. Centers for Disease Control and Prevention (CDC) as well as the United Kingdom's Department of Health recommend that travelers consider vaccination or be immunized if they plan to visit any high risk region. Areas of highest risk are the Middle East, Africa, Mexico and Asia especially the Indian subcontinent. Approximately 900 cases of typhoid are notified in the U.K. and U.S. each year, of which 70 - 80% are contracted abroad.

The Risk - The numbers of business and leisure travelers from the developed world traveling to the developing world continues to increase every year. These travelers risk contracting a range of infectious and potentially debilitating, or even fatal, diseases not prevalent in the developed world. Once infected they may then import the disease on their return, which places not just the traveler but also those with whom they come into contact at risk. The need for new and improved vaccines, to provide effective protection against a wide range of infectious diseases, remains strong.

The Disease - Typhoid, also known as typhoid fever, is caused by infection with the bacterium Salmonella Typhi and is usually caught by consuming contaminated food and water based drinks. This contamination usually arises from poor hygiene and sanitation.

The Vaccine - Emergent is developing a novel oral typhoid vaccine, which will give business and leisure travelers the option of an easy to use effective single-dose oral vaccine, which can be taken before travel. Current typhoid vaccines require either a three to four-dose regime for the oral vaccine or an injection.

Emergent BioSolutions Inc. is dedicated to the research, development and manufacture of novel products which 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. The company currently employs more than 450 people with facilities in Gaithersburg and Frederick, Maryland, Lansing, Michigan and Berkshire, U.K. More information about Emergent BioSolutions and its subsidiaries can be found at http://www.ebsi.com/

Emergent BioSolutions Inc.

CONTACT: Kim Brennen Root of Emergent BioSolutions, +1-517-327-1543

Web site: http://www.ebsi.com/

Source: PRNewswire

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