(Adds details on new offer, background, share price move)
June 2 (Reuters) - U.S.-based Sterigenics International has sweetened its takeover offer for Nordion Inc, the Canadian medical isotope producer, to $805 million after a previous bid failed to attract enough shareholder support, Nordion said on Monday.
Sterigenics has agreed to pay $13 in cash for each Nordion share, up from its previous offer of $12.25, to try to clinch the deal.
A shareholder vote on the earlier Sterigenics offer fell short of required support. As of the May 30 proxy voting deadline, 65.2 percent of shares had been voted in favor of the deal, short of the required 66-2/3 percent support, Ottawa-based Nordion said.
Nordion said the sweetened bid came after it received another unsolicited acquisition proposal from an unnamed third party for the all of its shares at a price of $12.50 each, cash. Nordion said the unnamed party is the same one that had come in with a separate proposal in late April.
Last month, Sterigenics, a sterilization services provider owned by private equity firm GTCR LLC, had raised its buyout offer to $758 million from $727 million after Nordion received the initial rival bid from the unnamed buyer.
Nordion said its board has determined that the revised offer from Sterigenics is superior to the rival bid, and it has advised its shareholders to tender their shares to it.
Sterigenics' bid sent shares in Nordion surging 7.6 percent to $12.86 on Monday morning on the New York Stock Exchange.
A shareholder vote that had been scheduled for June 3 in Ottawa has been delayed till June 6. (Reporting by Euan Rocha in Toronto and Rod Nickel in Winnipeg, Manitoba; Editing by Jeffrey Benkoe; and Peter Galloway)