Australia's Sigma seeks better offer from Aspen

Embattled Australian drug maker Sigma Pharmaceuticals said it will work with South Africa's Aspen Pharmacare to improve its A$648 million ($567 million) bid, but did not endorse the offer and declined to extend Aspen's exclusivity.

The move sent Sigma's shares down 1.1 percent to A$0.45, 18 percent below Aspen's offer price, reflecting increasing doubts that a deal will go ahead.

In its first detailed response since Aspen trimmed its offer to A$0.55 a share from A$0.60, Sigma said it was willing to work with Aspen to help it come up with a better proposal, but made clear it was not about to cave in despite its debt woes.

"Aspen has also been advised that such discussions should not be interpreted as a willingness on the part of the board to recommend to Simga shareholders an offer of A$0.55 per share," Sigma's general counsel Sue Morgan-Dethick said in a statement.

Aspen trimmed its offer last week following a review of Sigma's books and a profit warning from Sigma about its generic drugs business.

Sigma said it is still looking at asset sales and reviewing expressions of interest for parts of the company, including its generics business, and told shareholders to take no action.

It is under pressure from lenders to sell A$100 million worth of assets by March to help cut debt.

(Reporting by Sonali Paul; editing by Balazs Koranyi)