CAMBRIDGE, U.K., Feb. 14, 2002 (PRIMEZONE) -- Acambis plc ("Acambis") (LSE:ACM)(Nasdaq:ACAM) announces that it has successfully completed a second Phase II trial of its ChimeriVax-JE vaccine against Japanese encephalitis ("JE").
The aims of the trial were to compare the safety and immunogenicity of a range of dose levels of the vaccine and to ascertain the need, or otherwise, for a second dose to achieve maximum immunity. The randomized, double-blind placebo-controlled out-patient trial was conducted in 99 healthy adults.
The preliminary findings from the trial are as follows:
-- ChimeriVax-JE was well-tolerated at all doses tested
-- 98% of subjects developed JE-neutralizing antibodies within
one month of vaccination
-- The seroconversion rate was similar across all dose levels. The
lowest dose was approximately 1,000 times lower than the highest
dose used previously
-- A single dose of ChimeriVax-JE was as immunogenic as two doses of
vaccine
These results reinforce the belief that ChimeriVax-JE has potential as a single-dose vaccine for travellers to JE-endemic areas. The trial also demonstrated that the vaccine is strongly immunogenic, with better than expected results at even the lowest dose levels.
Based on these encouraging results, Acambis will now undertake the necessary process development and scale-up activities to manufacture vaccine for pivotal Phase III trials, which are targeted to begin next year. In parallel, additional Phase II trials are planned this year, including the first evaluation of ChimeriVax-JE in children living in JE-endemic areas.
Dr. John Brown, Chief Executive Officer of Acambis, said: "This positive set of results is particularly significant as ChimeriVax-JE is our lead product developed using our proprietary ChimeriVax technology, which is also being applied to vaccines against dengue fever and West Nile encephalitis. The fact that even low doses of ChimeriVax-JE were strongly immunogenic is very encouraging, and the results reinforce our confidence that this is an ideal for travellers."
Notes to editors:
Acambis
Acambis is a biopharmaceutical company discovering, developing and manufacturing vaccines to prevent and treat infectious diseases. It has operations in Cambridge, UK, and in Cambridge and Canton, Massachusetts, US. It has a broad portfolio of vaccine product candidates undergoing clinical trials and technology platforms that provide the basis for further vaccine product candidates.
ChimeriVax-JE Phase II Trial Results
The randomized, double-blind placebo- and yellow fever vaccine-controlled out-patient trial was conducted in the US under an FDA IND. 99 healthy adults randomized to receive two intra-muscular injections (30 days apart) of one of five dose levels of ChimeriVax-JE (5.8, 4.8, 3.8, 2.8 or 1.8 log10 plaque-forming units [PFU]) or a single dose of ChimeriVax-JE (4.8 log10 PFU) preceding or following placebo or a standard dose of yellow fever vaccine.
96 of the 98 subjects (98%) whose serum was available for analysis mounted a JE-neutralizing antibody response within 30 days after vaccination. The seroconversion rates and mean titres of neutralizing antibodies were statistically the same when comparing one injection to two injections (at all dose levels) and when comparing the highest (5.8 log10 PFU) with the lowest (1.8 log10 PFU) dose levels administered.
Japanese encephalitis
Japanese encephalitis is a mosquito-borne viral disease that occurs throughout Asia and in parts of Australia. Three billion people live in regions where JE is endemic and some 14 million people travel to these regions every year from major developed countries such as the US, Canada and western Europe. The potential market for Acambis' ChimeriVax-JE vaccine is estimated to be around $300m a year.
This, and other news releases relating to Acambis, can be found on the Company's website at www.acambis.com
This news release contains forward-looking statements that involve risks and uncertainties, including the timing and results of clinical trials and other product development and commercialisation risks, the risks of satisfying the regulatory approval process in a timely manner, the need for and the availability of additional capital, and other risks detailed in the Company's filings with the Securities and Exchange Commission. These forward-looking statements are based on estimates and assumptions made by the management of Acambis and are believed to be reasonable, though are inherently uncertain and difficult to predict. Actual results or experience could differ materially from the forward-looking statements.