UCB has increased its shareholding in Wilex, as rumours abound that the German biotechnology firm is a takeover target but not necessarily for the Belgian group.

UCB has bought an additional 6.65% of Wilex, to bring its stake to just over 18%, at a price reported to be in the region of 7 million euros. The firms have been partners since January 2009 when the Munich-based company acquired UCB's entire preclinical oncology portfolio, comprising two small-molecule and three antibody programmes.

Under the terms of that deal, the Brussels-headquartered group retained exclusive rights to re-purchase each of the five programmes following completion of initial clinical feasibility studies and Wilex would get milestone payments and royalties. One of the compounds, a MEK inhibitor known as WX554, moved into Phase I at the end of last year.

Ismail Kola, president of new medicines at UCB, said the alliance gives his firm the opportunity to focus its own R&D activities on core therapy areas, diseases of the central nervous system and immunology, “while benefiting from Wilex's specialised expertise, focus and know-how in oncology”.

After the UCB stake increase was announced, Wilex shares climbed 18.5% to close at 7.29 euros and the stock has been attracting interest since last week when dievini Hopp Biotech, the life sciences investment company of entrepreneur and co-founder of software giant SAP, Dietmar Hopp, raised its stake in the company to 31.24%. This is above the 30% threshold that triggers a mandatory takeover offer.

Analysts at WestLB issued a research note wondering whether there was now a battle for control taking place or whether UCB and dievini Hopp BioTech were preventing another shareholder, private equity group, Aapax, from selling its stake in the market at a depressed price. “Speculation around this, as well as the expectation of a takeover offer from dievini Hopp BioTech should drive the shares going forward,” the broker said.