Bayer has completed the sale of its anti-infectives research to fellow German company Santo Holding AG, continuing the trend of big pharmaceutical companies exiting or downsizing their involvement in the anti-infectives research.

Under the terms of the deal, Santo has created a new company, AiCuris, to develop and commercialise the portfolio. AiCuris based at Bayer’s Wuppertal site and is headed by Prof Helga Rubsamen-Waigmann, who formerly headed up anti-infectives research at Bayer HealthCare. Bayer will retain a minority holding in the new firm.

The companies did not release financial aspects about the transaction. Last November, Bayer said it planned to spin off the anti-infectives unit into a new company.

Big drug companies have shied away from anti-infectives research in recent years in favour of other therapeutic categories, mainly because new antibiotics tend to be reserved for last-line use for fear of generating resistance, slowing their uptake, and because they are used only in short courses rather than as chronic treatment. This can hold back peak sales to a few hundred million dollars, even for the most successful brands.

Since 2000, some of the household names in the drug business - including Wyeth, Aventis, Eli Lilly, Bristol-Myers Squibb, Abbott Laboratories - have cut or eliminated antibiotics research. The baton has now been passed to specialist companies which do not have such large sales expectations.

AiCuris will concentrate on developing new drugs for the treatment of viral and bacterial diseases, including human cytomegalovirus (HCMV), hepatitis C, HIV, herpes and Gram-positive bacterial infections.