Elan has said that two of its patents covering research mice have been upheld by a US court.

The US Court of Appeals for the Federal Circuit overturned an earlier lower court ruling on the patents for the mice, which are used to study potential drugs for Alzheimer's disease.

The ruling forms part of Elan's litigation with the Mayo Foundation. Elan is claiming that the foundation owes it a portion of licence fees received from licensing the patented mice to commercial pharmaceutical companies.

Elan declined to comment on the sums involved yesterday but analysts said the business in research mice was a sideline for the company and the amounts involved were not thought to be significant.

"It's more a defence of their intellectual property," said Mr Ian Hunter, analyst with Goodbody Stockbrokers.

Merrion Stockbrokers described the news as "a modest positive" for the company, coming on the back of good news for a number of Elan's key drugs.

But markets are still awaiting news from the company on its asset disposal programme, designed to raise €1.5 billion by the end of next year.

Shares in Elan closed 10 cents higher in Dublin yesterday at €3.00 while they gained 4.23 per cent in New York.