Cephalon increases Sirtex holding

US pharma Cephalon has increased its interest in delivery biotech Sirtex up to 41 per cent with the acquisition of just under 8,800,000 shares from founder Dr Bruce Gray.

Gray described the share transfer as Cephalon "drawing a line in the sand" with respect to its bid for the company.

"They have said they need 80 per cent of the shares by the 19th, and if not [Cephalon] will not extend the bid. Now it is up to the rest of the shareholders. It is not dependent on the major shareholders any more. I have tendered all my stock in accordance with our target statement. I have no idea what will come next," he said.

Sirtex shares are currently trading at around $AUD4.30, following a sharp dip from the April-long price hovering around $4.70.

The exchange prompted a swift response from ethical fund manager Hunter Hall, which applied to the ASX for a declaration of unacceptable circumstances on the bid on behalf of Australian Value Trust, the Value Growth Trust and the International Ethical Fund.

However, the ASX declined to issue the declaration, which was based on the assertion that Sirtex's shareholders did not have sufficient information to assess whether or not to accept the bid.

It also asserted there was a concern about the relationship between Cephalon, on the one hand, and Sirtex and its principal "shareholder" on the other.

A spokesman from Hunter Hall declined to comment on the application.