La Jolla Pharmaceutical Initiates Phase III Lupus Clinical Trial.

Business Editors/Health & Medical Writers

BIOWIRE2K

SAN DIEGO--(BW HealthWire)--Sept. 20, 2000

La Jolla Pharmaceutical Co. (Nasdaq:LJPC) today announced that it has initiated a Phase III clinical trial to demonstrate the safety and efficacy of its drug candidate for lupus, LJP 394.

LJP 394 is designed to reduce the levels of antibodies to double-stranded DNA, which are believed to be responsible for lupus kidney disease. It is estimated that about one-half of the one million lupus patients in the U.S. and Europe have kidney disease, the leading cause of morbidity and mortality in lupus patients.

"We are pleased to begin the pivotal Phase III clinical trial for our lead drug candidate," said Steven B. Engle, chairman and chief executive officer. "This study of several hundred lupus patients is designed to confirm the ability of LJP 394 to treat lupus kidney disease and to be the final clinical trial required for approval of a drug to treat this life-threatening disease. We plan to conduct this double-blind, placebo-controlled trial at about 75 major medical centers in North America and Europe."

The Phase III trial is designed to repeat the positive results from the Phase II/III trial for patients with high-affinity antibodies to LJP 394. The trial will enroll the same patient population -- patients with a history of kidney disease -- and have the same endpoints as the Phase II/III study. The company plans to enroll approximately 300 lupus patients to evaluate the potential of LJP 394 to prevent or delay renal flares, reduce the need for treatment with high-dose corticosteroids and/or chemotherapy drugs, and improve a patient's quality of life. Based on findings from the Phase II/III trial, patients will be treated with weekly 100 mg doses of LJP 394 or placebo for the duration of the study. The efficacy analysis will focus on patients with high-affinity antibodies for LJP 394.

Interested patients are encouraged to contact LJP by calling 888/30-LUPUS for information about the trial. Patients who have enrolled in previous clinical trials of LJP 394 will be permitted to enroll in the Phase III trial if they meet all of the study criteria. The Phase III trial has been named "PEARL," or Program Enabling Antibody Reduction in Lupus.

The Phase II/III study enrolled more than 200 patients who were treated for up to 18 months. In that trial, 89 percent of the patients had high-affinity antibodies to LJP 394. In patients with high-affinity antibodies to LJP 394, time to renal flare, the primary endpoint of the trial, was significantly increased in the drug-treated population when compared to the placebo-treated group (p = 0.008). In the high-affinity group, there were one-third as many renal flares in LJP 394-treated patients (7) compared to placebo-treated patients (21) (p = 0.007). Furthermore, in the high-affinity group, there were less than one-half as many treatments with high-dose corticosteroids and/or cyclophosphamide in drug-treated patients (13) compared to placebo-treated patients (34) (p less than 0.001). The drug appears to be well tolerated. There were no significant differences in serious adverse events between the drug-treated and placebo-treated groups in the Phase II/III trial.

Results from the Phase II/III trial will be presented in three papers at the American College of Rheumatology Annual Meeting in Philadelphia on Oct. 31, 2000.

Lupus is a devastating autoimmune disease with poor treatment options and little or no innovation in treatment for decades. It is a chronic, life-threatening disease most commonly affecting women. The onset of the disease usually occurs during their childbearing years.

In autoimmune diseases, the immune system reacts to the body's own tissues as if they were foreign invaders and mounts an attack upon them by producing antibodies. The consequences of this antibody production can be devastating. In lupus, antibodies to double-stranded DNA are believed to be responsible for potentially severe and often progressive kidney disease that can lead to kidney failure and the need for dialysis or kidney transplantation. Renal flares are life-threatening episodes of disease activity where kidney tissue is destroyed. Current therapies -- high doses of corticosteroids and chemotherapy drugs -- have increased 10-year patient survival rate, but the toxic effects of these drugs have made them a major cause of morbidity and mortality in lupus.

La Jolla Pharmaceutical's drug candidates, known as Toleragens(R) are designed to arrest the production of disease-causing antibodies without suppressing the healthy functions of the immune system. Its Tolerance Technology(R) platform has been shown to reduce targeted disease-causing antibodies in five human clinical trials in lupus patients.

La Jolla Pharmaceutical Co. (LJP) is a San Diego-based biotechnology company developing therapeutics for antibody-mediated diseases, such as lupus and stroke, which afflict several million people in the United States and Europe. The company is also developing drugs for antibody-mediated stroke, heart attack, and deep-vein thrombosis, for xenotransplantation, and for other antibody-mediated diseases. The company's common stock trades on The Nasdaq Stock Market under the symbol LJPC. For more information about the company, visit our Web site: www.ljpc.com.

Except for historical statements, this press release contains forward-looking statements, including without limitation statements regarding the analysis of results from preclinical and clinical studies as well as La Jolla Pharmaceutical's drug candidates and drug development plans. These forward-looking statements involving risks and uncertainties, and a number of factors, both foreseen and unforeseen, could cause actual results to differ materially from those anticipated. Clinical results for LJP 394 are derived from a trial that was terminated prior to completion, and certain data are incomplete. Future analyses of clinical trial results may not necessarily support conclusions to date. The company's blood test to measure binding affinity for LJP 394 is experimental and has not been validated by independent laboratories. Tolerance, or the specific inactivation of pathogenic B cells, is a new technology that has not been proven. The company's ability to develop and sell its products in the future may be affected by the intellectual property rights of third parties. Future clinical trials of the company's drug candidates may have negative or inconclusive results. Future clinical trials of the company's drug candidates may not support results of preclinical or other prior trials and pre IND studies of the company's new candidate for treating antibody-mediated thrombosis may reveal a potential safety issue requiring the development of a new candidate. Any delays in testing of the company's drug candidates and/or termination of development by the company would result in delays or lack of government approval to market the compound. The development of drug candidates involves many risks and uncertainties, including, without limitation, whether the drug can provide a meaningful clinical benefit, and any positive results observed to date may not be indicative of future results. La Jolla Pharmaceutical's other potential drug candidates, including its Toleragen candidate for xenotransplantation, which has not progressed to clinical trials, involve comparable risks. Interested parties are urged to review the risks detailed from time to time in La Jolla Pharmaceutical company's Securities and Exchange Commission (SEC) filings, including the report on Form 10-K for the year ended Dec. 31, 1999 and in Form 10-Q for the quarter ended June 30, 2000.