Facet Biotech Corp has rejected partner Biogen Idec’s latest takeover bid and revealed that inquiries have come in from other companies who are interested in a deal.

Facet’s board of directors has unanimously recommended that stockholders reject the unsolicited, offer Biogen of $17.50 per share in cash, which would value the company at around $493 million. That bid, which was up from a previous offer of $14.50 per share, was described by the US biotechnology giant as a “best and final” one, but has been dismissed as inadequate.

Facet chief executive Faheem Hussein said that Biogen is “materially undervaluing our assets while overstating our liabilities, and their offer demonstrates an incomplete understanding of our pipeline and technologies”. In a letter to shareholders, he said the offer “provides insufficient value to our pipeline”, including daclizumab, a late-stage drug already being developed for multiple sclerosis with Biogen.

As for the rest of the pipeline, Facet is currently investigating volociximab in various open-label clinical trials in patients with advanced solid tumours, again with Biogen and is collaborating with Bristol-Myers Squibb on elotuzumab which is in Phase I studies for multiple myeloma.

Mr Hussein also claimed that the revised offer “continues to be funded in large part by Facet's cash, marketable and investment securities”. He added that the firm’s “strong balance sheet continues to provide the resources to support development activities” through 2012.

Facet’s CEO then dropped something of a bombshell, saying that since Biogen’s initial offer earlier this year, “we have enabled certain parties who have expressed interest in the company and its assets to enter into confidentiality agreements and conduct due diligence”.

Mr Hussein added that the firm will allow Biogen to join those interested groups in looking at the books and has also asked its financial advisor, Centerview Partners to “solicit additional third parties that may have an interest in a transaction that the board would find in our stockholders' best interests”.

How Biogen responds to the news that Facet has other admirers, and whether that ‘final” offer will be upped, remains to be seen.