LA JOLLA PHARMACEUTICAL TO PRESENT AT MERRILL LYNCH CONFERENCE

SAN DIEGO, January 30, 2003 -- La Jolla Pharmaceutical Company (Nasdaq: LJPC) today announced that Chairman and CEO Steven B. Engle will present at the Merrill Lynch Global Pharmaceutical, Biotechnology & Medical Device Conference in New York City on Tuesday, February 4, 2003 at 4:45 p.m. Eastern Time. An audio webcast of the presentation will be available through the Merrill Lynch Web site at http://www.mlx.ml.com.

La Jolla Pharmaceutical Company is a biotechnology company leading the development of therapeutics for antibody-mediated autoimmune diseases afflicting several million people in the United States and Europe. The Company is developing Riquent™, formerly known as LJP 394, for the treatment of lupus kidney disease, a leading cause of sickness and death in patients with lupus. The Company is also developing LJP 1082 for the treatment of antibody-mediated thrombosis, a condition in which patients suffer from recurrent stroke, deep-vein thrombosis and other thrombotic events. The Company's common stock is traded on The Nasdaq Stock Market under the symbol LJPC. For more information about the Company, visit our Web site: http://www.ljpc.com.

Except for historical statements, this press release contains forward-looking statements involving significant risks and uncertainties, and a number of factors, both foreseen and unforeseen, could cause actual results to differ materially from our current expectations. Our analyses of clinical results of Riquent™, previously known as LJP 394, our drug candidate for the treatment of systemic lupus erythematosus ("lupus"), and LJP 1082, our drug candidate for the treatment of antibody-mediated thrombosis ("thrombosis"), are ongoing and future analyses could result in a finding that these drug candidates are not effective in large patient populations, do not provide a meaningful clinical benefit or may reveal a potential safety issue requiring us to develop new candidates. Our blood test to measure the binding affinity for Riquent™ is experimental, has not been validated by independent laboratories, may require regulatory approval and may be necessary for the approval and the commercialization of Riquent™. Our other potential drug candidates are at earlier stages of development and involve comparable risks. Analysis of our clinical trials could have negative or inconclusive results. Any positive results observed to date may not be indicative of future results. Even if results are promising, the U.S. Food and Drug Administration ("FDA") may require additional clinical trials, or may not approve our drugs. Our ability to develop and sell our products in the future may be affected by the intellectual property rights of third parties. Additional risk factors include the uncertainty of: obtaining required regulatory approvals; FDA approval of our manufacturing facilities and processes; the increase in capacity of our manufacturing capabilities for possible commercialization; successfully marketing and selling our products; our lack of manufacturing, marketing, and sales experience; generating future revenue from product sales or other sources such as collaborative relationships; future profitability; our need for additional financing; and our dependence on patents and other proprietary rights. Readers are cautioned to not place undue reliance upon forward-looking statements, which speak only as of the date hereof, and we undertake no obligation to update forward-looking statements to reflect events or circumstances occurring after the date hereof. Interested parties are urged to review the risks described in our other reports and registration statements filed with the Securities and Exchange Commission from time to time, including the report on Form 10-K for the year ended December 31, 2001.