Shares in Sweden"s Orphan Biovitrum (Sobi) (SOBIV.ST) plunged 23% on Friday after U.S. private equity firm Advent International and Singapore"s sovereign wealth fund said they were withdrawing their bid for the drugmaker. The company in September agreed to an $8 billion takeover by Advent and Aurora, an investment vehicle of Singapore"s GIC Pte Ltd, through Agnafit Bidco. "Since the acceptance level condition has not been fulfilled, Agnafit Bidco hereby withdraws the offer," Agnafit Bidco said in a statement. Having soared 36% this year through Thursday, Sobi shares were down 23% at 1336 GMT to 174.60 crowns ($19.20). The 235 crowns per share offer had represented a premium of 34.5% to its Aug. 25 closing price. Sobi Chairman Hakan Bjorklund said the board, which had supported the bid, was confident the company would deliver on its goals to expand globally, invest in haematology, and expand in immunology and specialty care. "Subsequent discussions regarding the potential execution of the transaction have been directly dealt with between the bidding consortium and Sobi shareholders," Bjorklund said in a statement. Sweden"s Investor AB (INVEb.ST), which owns a 35% stake in the rare disease drugmaker, said that its focus would now be to "continue to create long-term value for Sobi"s shareholders". Agnafit said shares corresponding to around 87.3% of outstanding shares in Sobi, which sells drugs within haemophilia, autoimmune diseases, metabolic diseases and cancer supportive care, had been tendered, below its condition of more than 90%. Anglo-Swedish drugmaker AstraZeneca (AZN.L) holds an 8% stake in Sobi, whose best-selling drug, established haemophilia A treatment Elocta with 4.6 billion crowns in 2020 revenue, is facing competition from Roche"s (ROG.S) Hemlibra. ($1 = 9.1066 Swedish crowns) Reporting by Helena Soderpalm, editing by Niklas Pollard and Jason Neely