La Jolla Pharmaceutical Provides Update on Its Auction Rate Securities and Its Ongoing Riquent® Phase 3 "ASPEN” Lupus Trial

La Jolla Pharmaceutical Company (NASDAQ: LJPC) today announced an update on its auction rate securities and continued progress in the ongoing double-blind, placebo-controlled, randomized Phase 3 study of Riquent^® (abetimus sodium), its drug candidate for systemic lupus erythematosus ("SLE” or "lupus”).

In October 2008, the Company entered into an agreement with UBS A.G., giving the Company the right to sell its auction rate securities to UBS at par value totaling $10 million beginning in January 2009. As such, the Company anticipates liquidating these investments in early January 2009, subject to the ability of UBS to consummate the transaction. In early December, the Company obtained a credit line from UBS for up to $6 million secured by these auction rate securities.

"The Company continues to explore potential partnership alliances as well as other sources of funding,” said Deirdre Gillespie, President and CEO of La Jolla Pharmaceutical Company. "We expect the availability of the $10 million from our auction rate securities will give us additional flexibility to focus on these funding initiatives. We are excited that the Riquent Phase 3 study, which is the largest lupus trial conducted to date, continues to progress towards our upcoming interim analyses and final results in 2009.”

Update on Phase 3 ASPEN Study

The study is an event-driven trial designed to be completed when 128 renal flares have occurred. The current overall renal flare rate continues to be lower than the original trial assumption. As a result, in an effort to shorten the time to achieve the required number of renal flares in the most cost effective manner, the Company is continuing enrollment beyond the most recently targeted 800 patients.

To date, 890 patients have been enrolled in the trial at 172 clinical trial sites. The Phase 3 trial includes two interim efficacy analyses which will occur when approximately 70% and 85% of renal flares are achieved. The first interim efficacy analysis is expected to be conducted in Q1 of 2009 and the second in mid-year 2009. Each interim efficacy analysis has a pre-specified p value of p < 0.001. With continued funding, the Company projects that the trial will complete in the second half of 2009.

The Independent Data Monitoring Board (DMB) has completed a fourth safety review of the safety data and has not indicated any safety issues.

Phase 3 Study Design

The Phase 3 study is designed to assess the ability of Riquent treatment to prevent or delay the time to renal flare in lupus patients with a history of renal disease and with antibodies to dsDNA. The study is an event-driven trial designed to be completed when 128 renal flares have occurred. Equal numbers of patients are being treated with 300 mg per week, 900 mg per week, or placebo. The pre-specified p value at the end of the study is p < 0.05.

A lupus renal flare is a potentially life-threatening increase in inflammation of the kidney due to lupus. A renal flare often requires treatment with immunosuppressive agents which can have severe side effects. Riquent is also being studied to assess whether drug treatment decreases proteinuria as was observed in previous clinical trials. Proteinuria, or protein in the urine, is a common problem for patients with renal disease and is an indicator of renal damage.

Riquent has received an Approvable Letter and Fast Track status from the Food and Drug Administration and has Orphan Drug designation in the United States and Europe.

About Riquent

Riquent is being developed to specifically treat lupus renal disease by preventing or delaying renal flares, a leading cause of sickness and death in lupus patients. It is also being studied to assess whether Riquent treatment improves proteinuria, as was observed in previous clinical trials. Proteinuria is an indicator of abnormal renal function. Riquent has been well tolerated in all 14 clinical trials, with no overall difference in the adverse event profiles for Riquent-treated patients compared with placebo-treated patients. Riquent specifically reduces circulating levels of anti-dsDNA antibodies and is also designed to specifically suppress the B cells that make these antibodies. Decreases in these antibodies are believed to be associated with a decreased risk of renal flare. Although clinical benefit has not yet been proven, Riquent treatment has significantly reduced these antibody levels in all clinical trials in which they were measured.

About Lupus

Lupus (systemic lupus erythematosus) is a chronic, potentially life-threatening autoimmune disease. About 90% of lupus patients are female, and many are diagnosed with the disease during their childbearing years. Approximately 50% of lupus patients have renal disease which can lead to irreversible renal damage, renal failure and the need for dialysis, and is a leading cause of death in lupus patients. Latinos, African Americans, and Asians face an increased risk of serious renal disease associated with lupus. The current standard of care for lupus renal disease often involves treatment with high doses of corticosteroids and immunosuppressive drugs that can cause severe side effects including diabetes, hypertension, and sterility and may leave patients vulnerable to opportunistic infections. To date, no lupus-specific drug has been approved in the U.S.

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. More information about the Company is available on its Web site: http://www.ljpc.com.

The forward-looking statements in this press release involve significant risks, assumptions and uncertainties, and a number of factors, both foreseen and unforeseen, could cause actual results to differ materially from our current expectations. Forward-looking statements include those that express a plan, belief, expectation, estimation, anticipation, intent, contingency, future development or similar expression. The analyses of clinical results of Riquent^® (abetimus sodium), previously known as LJP 394, our drug candidate for the treatment of systemic lupus erythematosus (lupus), and any other drug candidate that we may develop, including the results of any trials or models that are ongoing or that we may initiate in the future, 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. The analysis of the data from our previous Phase 3 trial of Riquent showed that the trial did not reach statistical significance with respect to its primary endpoint, time to renal flare, or with respect to its secondary endpoint, time to treatment with high-dose corticosteroids or cyclophosphamide. The results from our clinical trials of Riquent, including the results of any trials that are ongoing or that we may initiate in the future, may not ultimately be sufficient to obtain regulatory clearance to market Riquent either in the United States or any other country, and we may be required to conduct additional clinical studies to demonstrate the safety and efficacy of Riquent in order to obtain marketing approval. There can be no assurance, however, that we will have the necessary resources to complete any current or future trials or that any such trials will sufficiently demonstrate the safety and efficacy of Riquent. Our ability to develop and sell our products in the future may be adversely affected by the intellectual property rights of third parties or the validity or enforceability of our intellectual property rights. Additional risk factors include the uncertainty and timing of: our ability to raise additional capital; obtaining required regulatory approvals, including delays associated with any approvals that we may obtain; the timely supply of drug product for clinical trials; our ability to pass all necessary regulatory inspections; 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; our ability to make use of the orphan drug designation for Riquent; generating future revenue from product sales or other sources such as collaborative relationships; future profitability; and our dependence on patents and other proprietary rights. Accordingly, you should not rely upon forward-looking statements as predictions of future events. The outcome of the events described in these forward-looking statements are subject to the risks, uncertainties and other factors described in the "Risk Factors” contained in our Annual Report on Form 10-K for the year ended December 31, 2007, and in other reports and registration statements that we file with the Securities and Exchange Commission from time to time. We expressly disclaim any intent to update forward-looking statements.