Pfizer's October 2006 acquisition of DNA-vaccine specialist PowderMed was the largest ever acquisition of a UK biotech. PowderMed's investors saw a solid return on the deal, which underscored Big Pharma's rush to spread their bets on next-generation large-molecule platforms.

European developers of therapeutic cancer vaccines are making steady, if slow progress towards clinical and regulatory success. But late-stage setbacks and delays at North American firms-which are several years more advanced and thus bearing the brunt of working out the regulatory kinks-highlight the challenges associated with bringing a cancer vaccine to market. Given the various technological and commercial approaches to immunotherapy on either side of the ocean, European firms are closely watching the progress of similar technologies in the US.

Chiron's acquisition of PowderJect is the most recent sign that the vaccines industry is coming of age, taking the field's only two mid-sized players up among the top-ranking Big Pharma. This deal was largely about infrastructure. But it suggests any European biotech with a valuable asset--be it product or distribution network--is an attractive takeover target for US firms.