The price tag was estimated at $25 billion to $30 billion, making it one of biotech's biggest deals, but that was also seen as quite rich. Specifically, Mullen says some prospective bidders were concerned about Tysabri, Biogen's MS drug, which was temporarily pulled from the market almost three years ago after being linked to a rare brain disease. Some fear the problem could happen again, even though Biogen has repeatedly tried to reassure Wall Street by noting that there haven't been any recurrences of the disease since the drug returned to the market in 2006.
"I think there is a fair bit of fear, loathing, and tort out there," Mullen told investors at the JP Morgan investor conference in San Francisco this week, referring to the threat of lawsuits.
In addition, Mullen said some prospective Biogen Idec buyers were uncomfortable with the company's partnerships for its two other major drugs. Biogen Idec shares the rights to Avonex, another MS treatment, with Elan. And it works with Genentech to market Rituxan, which treats non-Hodgkins lymphoma and rheumatoid arthritis. Both Elan and Genentech had options to buy Biogen Idec's stake in the drugs in the event of a sale, leading some to wonder whether they could potentially block a deal.
But Mullen disputed reports that Biogen's sale process was so restrictive that it may have kept some potential buyers at bay. While they were barred from trying to negotiate with Elan or Genentech before submitting an offer, he says, they would have had a chance to do so before completing the deal.
"I think the process was thorough," Mullen told investors. "I thought it was professional."