La Jolla Pharmaceutical Company (Nasdaq:LJPC) today announced the pricing of an underwritten public offering of 15,614,834 units, with each unit consisting of one share of common stock and a warrant to purchase 0.25 shares of common stock, at a price to the public of $1.92125 per unit for gross proceeds of $30 million. The Company expects that the net offering proceeds, after deducting underwriting discounts and commissions, will be approximately $28.2 million. The warrants, which represent the right to acquire a total of 3,903,708 shares of common stock, will be exercisable at a price of $2.15 per share and have a five-year term. All of the units are being sold by the Company. The offering is expected to close on May 12, 2008, subject to customary closing conditions.

This press release does not constitute an offer to sell or the solicitation of an offer to buy nor shall there be any sale of these securities in any state or jurisdiction in which such offer, solicitation or sale would be unlawful prior to registration or qualification under the securities laws of any such state or jurisdiction. The offering may be made only by means of a prospectus supplement and the accompanying prospectuses.

This offering is being made pursuant to two effective shelf registration statements. UBS Securities LLC and Canaccord Adams Inc. acted as joint bookrunning managers for the offering. A prospectus supplement and the accompanying base prospectuses will be filed with the Securities and Exchange Commission and will be available on the SEC’s website at www.sec.gov. Copies of the prospectus supplement and accompanying base prospectuses may be obtained, when available, upon making a request in writing to UBS Securities LLC, Prospectus Department, 299 Park Avenue, New York, New York 10171 or to Canaccord Adams Inc., Equity Capital Markets, 99 High Street, 11th Floor, Boston, Massachusetts 02110.

This press release contains “forward-looking statements” within the meaning of federal securities law. The forward-looking statements in this press release are subject to numerous risks and uncertainties, including the risk the offering may not be completed as described herein, or at all.

About La Jolla Pharmaceutical Company

La Jolla Pharmaceutical Company is dedicated to improving and preserving human life by developing innovative pharmaceutical products. The Company’s leading product in development is Riquent®, which is designed to treat lupus renal disease by preventing or delaying renal flares. Lupus renal disease is a leading cause of sickness and death in patients with lupus. The Company has also developed potential small molecule drug candidates to treat various other autoimmune and inflammatory conditions. The Company’s common stock is traded on The NASDAQ Global Market under the symbol LJPC.

Company Contact:
La Jolla Pharmaceutical Company
Andrew Wiseman, Ph.D., Sr. Director of Investor Relations
858-646-6615
andrew.wiseman@ljpc.com
or
Media Contact:
The Communications Strategy Group Inc.
Edward Agne, President, 781-631-3117
edagne@comstratgroup.com