Irish biotech Elan said it expects a move that will split the bulk of the company’s drug-discovery business into a new listed company to be completed within days.

Shareholders agreed at an extraordinary general meeting last week to split the company in two, with the new company, Prothena, to focus on early-stage drug development and research.

The company said it was anticipated that Prothena ordinary shares will begin trading on a "when issued" basis on the Nasdaq on December 18th, and "regular way" on December 21st, under the symbol PRTA.

Elan will continue to own the rights to its multiple sclerosis drug Tysabri and certain other late-stage drug development candidates.

Under the deal, Elan shareholders will directly own 82 per cent of Prothena, which will be listed on Nasdaq. The remaining 18 per cent will be held by Elan.