Japanese drugmaker Astellas Pharma Inc. said Tuesday it has launched its unsolicited $3.5 billion takeover bid for the U.S. biotech company OSI Pharmaceuticals Inc. and said it has filed a lawsuit to protect the offer from challenges.
Astellas said its indirect subsidiary, Ruby Acquisition Inc., began cash tender offer of $52 a share for all outstanding shares of the Melville, N.Y., company. It expires at midnight Eastern time on March 31.
OSI shares have traded above the offered price since it was disclosed Monday. The shares rose 20 cents to $56.45 in morning trading Tuesday.
The Japanese company also said it filed a lawsuit in Delaware to prevent OSI from interfering with its offer.
Astellas said Monday it would consider "all means necessary" to complete the deal after being rebuffed several times by OSI executives.
OSI advised shareholders on Monday to take no action "at this time" on the offer. Executives said that price undervalues their company, and they offered to provide Astellas with "non-public information which is fundamental to its valuation of OSI."
OSI focuses on oncology, diabetes and obesity treatments. Astellas has said the two companies will do better developing oncology drugs as a combination rather than separately, and the deal will help Astellas become an oncology leader.
The lawsuit was filed in Chancery Court in Delaware. It seeks to prevent OSI and its directors "from engaging in any action or inaction, including applying OSI's 'poison pill' rights plan, that has the effect of improperly impeding, thwarting, frustrating or interfering with the tender offer in a manner inconsistent with the directors' fiduciary duties," Astellas said.
Astellas' $52-per-share offer represents a 40 percent premium over the stock's closing price last Friday.