BioWorld International Correspondent

LONDON - As the threat of bioterrorism looms larger, Acambis plc said it has won two further contracts with national governments to supply the smallpox vaccine it is currently developing for the U.S government.

John Brown, Acambis' CEO, told a teleconference audience, "We have now accepted orders from two more governments. They are relatively small in comparison to the U.S. [smallpox contracts], but are important in validating our approach."

At the moment, both governments want to remain anonymous, but Brown said the contracts will be fulfilled in 2003. He also confirmed that the government of Austria has announced it is buying the Acambis vaccine, but said no contract has been entered as yet. Acambis' partner, Baxter Healthcare, is marketing the vaccine to governments worldwide.

Those deals follow on from the 209 million doses the U.S. government ordered in two separate contracts in 2001. For the U.S. government, Acambis already has started supplying the vaccine, while simultaneously putting it thorough clinical development. Brown said the company is now well into the Phase II trial of one version of the vaccine, ACAM 1000, and has completed recruitment for the Phase I trial of the second, ACAM 2000. Phase III trials of both ACAM 1000 and ACAM 2000 are planned for 2003.

The aim is to use modern cell culture techniques to product a vaccine with equivalent efficacy to Dryvax, the vaccine used during the world smallpox eradication program.

On the back of the U.S. contracts Acambis expects to move into profit in 2002, and estimates it will receive between $250 million and $290 million in revenues from the contracts in 2003.

Acambis, based in Cambridge, also reported positive results in a Phase I trial of a vaccine against dengue fever. That initial trial tested a vaccine containing one of what will be four components of the vaccine for safety, tolerability and immunogenicity in 56 healthy adults. All of the subjects developed neutralizing antibodies to the homologous dengue 2 serotype virus, while 96 percent developed neutralizing antibodies to a wild-type dengue 2 virus.

There are four virus serotypes, each of which must be included for an effective vaccine. Acambis has constructed vaccines against each serotype, and has tested the tetravalent version in preclinical models. "It is now full-steam ahead to move forward with the four-component vaccine," Brown said, adding that it would enter Phase I trials in the first half of 2003.

The vaccine is partnered with Aventis Pasteur, which is funding the program and has worldwide marketing rights. The World Health Organization estimates there are million dengue infections each year. The virus, which is transmitted by infectious mosquitoes, is now endemic in more than 100 countries.