Analysts have been reacting to the news that another UK biotechnology firm has lost its independence with Sanofi-Aventis’ purchase of Acambis.

The French drugmaker’s vaccines arm Sanofi Pasteur is to pay around £276 million in cash for Acambis, or £1.90 per share. This equates to a premium of 65.2% to the latter’s stock price of £1.15 at the close of business on July 24. Importantly, Sanofi said it has received “irrevocable undertakings to vote in favour of the scheme” from Invesco Asset Management and Goldman Sachs which together hold a stake of just over 42% of the Cambridge-based firm.

The Sanofi bid comes as no great surprise especially as the firm has already got collaborations in place with Acambis. These include the latter’s most advanced programme, ChimeriVax-JE for Japanese encephalitis, which is in Phase III, as well as vaccines against West Nile virus and dengue, both of which are in Phase II.

Acambis chairman Peter Fellner said that since a new management team had been appointed in 2007, the company had made important advances progressing its pipeline “and securing its mid-term financial position”. Sanofi recognises those advances and has made an offer “at a substantial premium”, he added.

He added that “Sanofi will benefit strategically not only from Acambis's pipeline and technologies but also from its significant US-based R&D and manufacturing infrastructure". The biggest benefit, in the short-term at least, is that the UK company was recently awarded a $425 million, ten-year contract by the Centers for Disease Control and Prevention to provide it with a warm-base manufacturing capability for the ACAM2000 smallpox vaccine which has been stockpiled by the US Government.

This type of deal is one of the reasons why Sanofi chose to acquire Acambis rather than fellow UK biotech and collaborator Oxford BioMedica, according to Global Insight pharma analyst Mitra Thompson. She notes that the French firm is preparing to invest more heavily in vaccines that could end up in national immunisation programmes, particularly in countries outside of its traditional growth markets.

Furthermore, Oxford BioMedica's cancer vaccine TroVax, to which Sanofi has global marketing rights, recently failed to reach a primary endpoint in a late-stage trial for renal cancer and, although the compound is still under development for other forms of cancer, “the setback likely played a role in influencing” the decision to go for Acambis instead, Ms Thompson wrote in a research note. She added that “the long-term revenue-earning potential for Acambis' vaccines seems considerably greater given their potential to be administered to a much wider patient population”.