Corixa Corporation, a developer of immunotherapeutics, has signed a definitive agreement with GlaxoSmithKline (GSK) under which GSK has agreed to acquire Corixa.

GSK will pay $4.40 in cash for each share of Corixa common stock, or common stock equivalent, or approximately $300 million, representing a 48 per cent premium to $2.98, which was Corixa's closing share price on April 28, 2005. GSK will assume Corixa's outstanding convertible notes, and after the transaction, the holders of these notes will have the right to cause GSK to redeem the notes for par plus accrued interest. Closing of this transaction is subject to customary conditions including, Hart-Scott-Rodino clearance and the approval of Corixa stockholders. The transaction is expected to close in the third quarter of 2005, Corixa said in a release.

Corixa CEO, Steven Gillis said, "GlaxoSmithKline has been a long-term and steadfast partner of Corixa, not only in proprietary vaccine antigen discovery and development, but as the leading customer for our adjuvants and as a co-developer of Bexxar. Acquisition of Corixa by GSK represents a logical step given the importance of MPL in multiple GSK vaccines. We look forward to working with GSK during the upcoming transition period by assisting with continued expansion of manufacturing operations in Montana, and by helping GSK to evaluate the other programs in the Corixa portfolio."