Shares of Alexion Pharmaceuticals Inc (ALXN.O) rose more than 7 percent on Tuesday following a report that Swiss drugmaker Roche Holding AG ROG.VX made an informal approach to the biotech company last week about a takeover.
Bloomberg, citing one unnamed person with knowledge of the matter, said that Alexion had rebuffed the approach and had retained Goldman Sachs to prepare for a possible offer.
Officials at Alexion and Roche were not immediately available to comment on the report. Goldman Sachs declined to comment.
Earlier this month, people familiar with the matter told Reuters that Roche was seeking financing for a potential bid for Alexion, whose market value neared $22 billion before Tuesday's share move.
Alexion sells Soliris, one of the world's most expensive medicines, used to treat a progressive, life-threatening blood disorder called paroxysmal nocturnal hemoglobinuria that causes destruction of red blood cells.
(Reporting by Bill Berkrot; Editing by Carol Bishopric)