XOMA Ltd, a leader in the discovery and development of antibody therapeutics, has entered into a definitive agreement with an institutional investor to sell 11,764,706 units, with each unit consisting of one of the company's common shares and a warrant to purchase 0.50 of a common share, for gross proceeds of approximately $10 million, before deducting placement agent fees and estimated offering expenses, in a 'registered direct' offering. The investor has agreed to purchase the units at a purchase price of $0.85 per unit. The warrants, which represent the right to acquire an aggregate of up to 5,882,353 common shares, will be exercisable at any time on or after May 15, 2009 and prior to the fifth anniversary of the closing of the transaction at an exercise price of $1.02 per share, which was 120 per cent of the closing price of the company's common shares on the Nasdaq Global Market on May 14, 2009. Canaccord Adams Inc acted as placement agent for the offering.

The transaction is expected to close on or about May 20, 2009, subject to satisfaction of customary closing conditions. The company intends to use the net proceeds of this offering to continue development of its XOMA 052 product candidate and for other working capital and general corporate purposes.

The securities described above are being offered by XOMA Ltd pursuant to a registration statement previously filed and declared effective by the Securities and Exchange Commission.

XOMA discovers, develops and manufactures therapeutic antibody and other agents designed to treat inflammatory, autoimmune, infectious and oncological diseases.