The Elan-Royalty Pharma takeover saga has taken yet another turn after the Irish drugmaker announced that it is now officially up for sale.

According to Elan, the decision comes "in light of expressions of interests received to date", and it also noted that "Royalty Pharma will be invited to participate if they so wish".

But the move seems to have divided industry observers.

Some believe it is a sign that the Dublin, Ireland-based group is weakening in its resolve to fight off Royalty's takeover bid, but others are of the opinion that it is yet another stalling tactic by Elan.

The group already announced earlier this year that it was considering potential suitors, and one advisor to Elan told the Financial Times that it has been approached with “a handful” of offers from pharmaceutical companies and plans to go ahead with a sale valued in excess of $13.50 a share.

This is above Royalty's current $13 a share cash offer, which could reportedly expire next week.

Elan shareholders are due to meet this morning (Monday) to hear voting results on four defensive transactions recently put forward by its chiefs.

These are: an investment of $1billion to take 21% of Theravance royalties relating to certain respiratory drug; the $340 million purchase of Austrian group AOP Orphan Pharmaceuticals AG; the sale of ELND005 for Alzheimer's disease; and a $200 million stock buyback plan.

Royalty's bid is currently contingent on a unanimous rejection of all four proposals; the group has been trying to get control of the Irish group since February.