Biogen partner Sobi and its Boston-based CEO field a takeover bid

Sweden's Sobi (STO: SOB), a close partner of Biogen, is in the crosshairs of a buyout bid. But the biotech isn't saying yet just who's doing the bidding.

In a release this morning the Stockholm-based Swedish Orphan Biovitrum, whose CEO moved to Boston last summer, confirmed "that it has received a preliminary and conditional non-binding proposal in relation to a possible offer for all shares issued by the company."

Word of the proposed takeover has been circulating for several days. Bloomberg reported on the takeover buzz two days ago, which comes after the company brought in Goldman Sachs to advise it--a move akin to staking a "for sale" sign in the front yard. The company is currently valued at about $3.5 billion, though its shares surged about 24% as word of the buyout bid spread in a feverish market for biotech M&A.

Last year marked a major turning point for Sobi, which has a high profile in the small biotech world in Sweden. It's partnered with Biogen ($BIIB) on hemophilia, and the Big Biotech won an approval last summer for Eloctate, part of a new wave of hemophilia drugs that has been changing the market. The approval for Eloctate, which is used to treat hemophilia A, followed an approval for Alprolix as a treatment for hemophilia B.

Its focus on rare diseases could attract a variety of suitors. Reuters speculated that Pfizer, which is a big buyer these days, may be in pursuit. Biogen Idec might scout for a deal at the right price. But with a market value of $3.5 billion, a number of larger outfits could fit the profile of a logical buyer.

Geoffrey McDonough was brought in to run Sobi in 2011 after a stint at Genzyme, another rare disease biotech. He was trained in Boston and returned there last fall, when the company opened an office in Waltham, MA.

- here's the release