EXHIBIT 99.1


                 LA JOLLA PHARMACEUTICAL TO PRESENT ADDITIONAL
              RIQUENT(R) RESULTS AT SG COWEN HEALTHCARE CONFERENCE

ANALYSES SHOW TREATMENT WITH RIQUENT REDUCED PROTEINURIA IN LUPUS PATIENTS

SAN DIEGO, MARCH 11, 2004 - La Jolla Pharmaceutical Company (Nasdaq: LJPC) today
announced additional data from its Phase 3 and Phase 2/3 clinical trials of
Riquent(R) (abetimus sodium) which showed that after one year of treatment, the
number of lupus patients with a reduction in proteinuria of at least 50% from
baseline was greater in the Riquent-treated group than in the placebo-treated
group. Proteinuria, or protein in the urine, results from ongoing kidney
inflammation. The reduction of proteinuria is one of the goals for the treatment
of lupus patients with renal disease. Monitoring the level of a patient's
proteinuria is a routine and important way to help determine the severity of
renal disease. These data were included in the Company's New Drug Application
for Riquent that is currently being reviewed by the United States Food and Drug
Administration.

Steven B. Engle, Chairman and CEO of La Jolla Pharmaceutical, will present these
results today at 10:15 a.m. and 11:15 a.m. Eastern Time during the SG Cowen 24th
Annual Healthcare Conference. The conference is taking place March 8-11, 2004 at
the Marriott Copley Place in Boston, MA. An audio webcast of the presentation
will be available through the Company's website at http://www.ljpc.com.

"The reductions in proteinuria we observed in patients treated with Riquent are
encouraging because a marked increase in proteinuria often corresponds to more
severe kidney inflammation and is an indication of the need for additional
treatment," said Kenneth R. Heilbrunn, M.D., Vice President of Clinical
Development.

In patients who had 24-hour urine protein measured at both baseline and at week
52 during the Phase 3 trial, 41% (26/63) of patients in the Riquent-treated
group with high-affinity antibodies to Riquent achieved a 50% or greater
reduction from baseline in the amount of protein in their urine at week 52,
compared with 28% (23/81) of patients in the placebo-treated group with
high-affinity antibodies (nominal p = 0.047). In patients who had 24-hour urine
protein measured at both baseline and at approximately week 52 during the Phase
2/3 trial, 44% (23/52) of patients in the Riquent-treated group with
high-affinity antibodies had a 50% or greater reduction from baseline in the
amount of protein in their urine at approximately week 52, compared with 18%
(11/61) of patients in the placebo-treated group with high-affinity antibodies
(nominal p = 0.002). The measurement of 24-hour urine protein was specified in
each protocol at defined time points, but the analysis of the reduction in
proteinuria was conducted on a retrospective basis.

ABOUT LUPUS AND RIQUENT

Lupus (systemic lupus erythematosus or SLE) is a chronic, life-threatening
autoimmune disease. About 90% of lupus patients are female, and many develop the
disease during their childbearing years. Approximately 50% of lupus patients
have renal disease, which can lead to irreversible kidney damage, kidney failure
and the need for dialysis.



 Latinos, African Americans and Asians face an increased risk of serious renal
disease associated with lupus. Riquent is designed to reduce levels of
antibodies to double-stranded DNA (dsDNA) that are believed to be responsible
for lupus renal disease, a leading cause of morbidity and mortality in lupus
patients. 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.

LA JOLLA PHARMACEUTICAL COMPANY

La Jolla Pharmaceutical Company is a biotechnology company developing
therapeutics for antibody-mediated autoimmune diseases and inflammationp
afflicting several million people in the United States and Europe. The Company
is developing Riquent(R), 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, and is in the early stage of
developing small molecules to treat various other autoimmune and inflammatory
conditions. The Company's common stock is traded on The Nasdaq Stock Market
under the symbol LJPC. For more information about the Company, visit its
website: 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. Forward-looking statements include
those that express a plan, belief, expectation, estimation, anticipation,
intent, contingency, future development or similar expression. Although our New
Drug Application ("NDA") for Riquent(R) has been accepted by the United States
Food and Drug Administration (the "FDA") for review, there is no guarantee that
the FDA will approve Riquent in a timely manner, or at all. 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 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 Phase 3 trial of Riquent has shown
that the trial did not reach statistical significance with respect to its
primary endpoint, time to renal flare. Although our NDA for Riquent has been
accepted for review by the FDA, the results from our clinical trials of Riquent
may not ultimately be sufficient to obtain regulatory clearance to market
Riquent either in the United States or Europe, 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 is no guarantee, however, that we will
have the necessary resources to complete any additional trial, that we will
elect to conduct an additional trial, or that any additional trial will
sufficiently demonstrate the safety and efficacy of Riquent. Our blood test to
measure the binding affinity for Riquent is experimental, has not been validated
by independent laboratories and will likely be reviewed as part of the Riquent
approval process. 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. In any event, regulatory authorities may require
additional clinical trials, or may not approve our drugs. Our ability to develop
and sell our products in the future may be adversely affected by the
intellectual property rights of third parties. Additional risk factors include
the uncertainty and timing of: obtaining required regulatory approvals,
including delays associated with any approvals that we may obtain; the clear
need for additional financing; our ability to pass FDA pre-approval inspections
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; 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 Annual Report on Form
10-K for the year ended December 31, 2002, and in other reports and registration
statements that we file with the Securities and Exchange Commission from time to
time.

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