Big Pharma may have abandoned anti-bacterial research some years ago, but biotechs are filling the void. Their approaches range from improving existing drugs to discovering entirely new targets. Yet although a handful in Europe, including recently floated Basilea and private firm Arrow, has attracted recent investor interest, it hasn't been the anti-bacterials per se that have drawn them in. Basilea benefited from its spin-off status; Arrow from a promising anti-viral project and broad portfolio. Despite growing concerns over bacterial resistance, the field needs success stories to draw investors back for good. Even then, the nature of the diseases and therapies under development mean it's likely to remain the domain of smaller firms.

The flotation of UK biotech Ark Therapeutics, likely followed closely by Switzerland's Basilea, suggest Europe's public markets are waking up. It's too early, as yet, to call the IPO window open, though. And the string of European hopefuls monitoring Ark's progress and hoping to follow in its wake will have to contend with investors who are far more discerning than during the last upturn. Late-stage products remain attractive, but there are few fixed rules.

Geneva-based start up Athelas Ltd. aims to develop anti-infective drugs based on new bacterial targets it discovers through its DiVi platform. The company's platform is based on the use of the amoeba as a model organism--by engineering single-gene mutant bacteria and infecting the amoebas with those bacteria, Athelas' scientists aim to identify drug targets that may be important in vivo, but that might not be found via traditional in vitro screening methods.