Biogen Idec Inc. said Thursday it raised its offer for Facet Biotech Corp. to $17.50 per share from $14.50 per share, valuing Facet at a total of $493 million.
The new price, which Biogen called its "best and final offer," represents a premium of almost 25 percent to Facet's Thursday closing price and is nearly double Facet's stock price on Sept. 2 _ the day before Biogen made its original offer.
Biogen said the new offer will expire Dec. 16. Facet has repeatedly turned down an earlier, unsolicited bid from Biogen that was worth a total of $356 million in cash.
The companies work together on the cancer drug candidate volociximab, and the multiple sclerosis drug daclizumab.
Shares of Redwood City, Calif.-based Facet closed at $17.23 on Thursday, and dropped 56 cents, or 3.3 percent, to $16.67 in aftermarket trading. Biogen shares were unchanged at $47.38.