For immediate release
7 March 2007

Notification of shareholding

The Company was notified on 6 March 2007 that QVT held or was interested in a total of 70,595,100 shares in the Company (28.2%).

Contacts

Development Capital Management     020 7355 7600
Roger Hornett
Tom Pridmore

Buchanan Communications     020 7466 5000
Charles Ryland
Isabel Podda

Numis Securities      020 7776 1500
Iain McDonald