UK biotechnology company Acambis has completed the first stage in filing for an investigational smallpox vaccine, ACAM2000, in the USA, and says it could see approval of the product before the end of the year.

Registration of ACAM2000 will represent the culmination of a breakneck effort to develop an improved smallpox vaccine as part of the USA’s bioterrorism defense strategy, set up in the wake of the 09/11 terrorist attacks. Acambis signed a deal to develop the ACAM2000 vaccine with the US government in November 2001, at a time when smallpox was considered the number one threat.

Acambis submitted its Biologics License Application on a rolling basis, starting with the first portion in January 2006. The file includes safety, tolerability and immunogenicity data obtained from clinical trials of ACAM2000 conducted in more than 3,800 subjects.

To date, Acambis has shipped around 180 million doses of ACAM2000 to the US government and received revenues of around $475 million in association with the contract. But approval of the vaccine may not draw a line under the UK biotech’s income from the project, said a spokeswoman for the firm.

Acambis is currently in negotiations with the US Centers for Disease Control and Prevention (CDC) for a ‘warm-based manufacturing’ contract that would see the company supply a batch of the vaccine, once a year, in order to maintain the integrity of the production process and ensure that capacity could be ramped up quickly if required.

The US government has said to wants to start initial testing of this type of warm-based manufacturing approach before September 2006, said the spokeswoman, and Acambis is hopeful that ACAM2000 may feature in its plans. The company estimates that such an angreement could bring in $20 million to $30 million a year in revenues.