Wednesday, Nov 19, 2003

Study in New England Journal of Medicine Shows Extending Raptiva (efalizumab) Treatment Provides Rapid and Continuous Benefit

RAPTIVA Now Available For Patients With Moderate-To-Severe Plaque Psoriasis

South San Francisco and Berkeley, Calif. -- November 19, 2003 --

Genentech, Inc. (NYSE: DNA) and XOMA Ltd. (Nasdaq: XOMA) today announced results of a study to be published in the November 20, 2003 issue of the New England Journal of Medicine in which patients with moderate-to-severe plaque psoriasis receiving 12 weeks of treatment with RAPTIVA™ (efalizumab) experienced a significant reduction in the signs and symptoms associated with psoriasis. In addition, most patients who received extended treatment to 24 weeks continued to benefit.

RAPTIVA is the first biologic therapy approved by the U.S. Food and Drug Administration (FDA) that is designed to provide continuous control of chronic moderate-to-severe plaque psoriasis and can be self-administered by patients as a single, once-weekly, subcutaneous injection. The results published today are from one of four randomized, placebo-controlled Phase III studies that were included in the companies' application to market RAPTIVA.

"Psoriasis is a life-long, chronic disease that requires continuous control of symptoms," said Dr. Mark Lebwohl, chairman, Department of Dermatology, Mt. Sinai School of Medicine. "These data support RAPTIVA's effectiveness in treating psoriasis and its ability to deliver rapid and sustained improvement of symptoms in patients."

Seventy-Seven Percent of Patients Sustained Response with Continued Treatment
The study reported today is based on a Phase III randomized, double-blind, parallel-group, placebo-controlled, multi-center study, involving 597 patients aged 18 to 75 with moderate-to-severe plaque psoriasis. Patients were randomized to receive subcutaneous RAPTIVA (1 or 2 mg/kg/wk) or placebo for 12 weeks. Based upon response after 12 weeks, patients either received an additional 12 weeks of RAPTIVA or placebo. Treatment was discontinued at 24 weeks and patients were followed for an additional 12 weeks.

At 12 weeks, more than half of RAPTIVA-treated patients experienced a clinically meaningful benefit, with some patients achieving clinical benefit as early as four weeks. After 12 weeks of RAPTIVA therapy, 22 percent of patients receiving 1 mg/kg of RAPTIVA and 28 percent of patients receiving 2 mg/kg of RAPTIVA reached the primary efficacy endpoint of 75 percent or greater improvement in Psoriasis Area and Severity Index (PASI) scores compared to five percent of placebo-treated patients.

Over this same interval, 52 percent and 57 percent of patients receiving 1 or 2 mg/kg RAPTIVA, respectively, achieved 50 percent or greater improvement in PASI compared to 16 percent of placebo-treated patients. Of the RAPTIVA-treated patients with 75 percent or greater PASI scores at 12 weeks, 77 percent who were continued on RAPTIVA maintained improvement through 24 weeks compared with 20 percent of patients switched to placebo. Approximately 90 percent of these patients maintained a 50 percent PASI improvement score at 24 weeks.

"These results clearly illustrate the benefit of continuous therapy with RAPTIVA and support the efficacy seen in over 3,000 patients treated with RAPTIVA in clinical trials to date," said Hal Barron M.D., F.A.C.C., Genentech's vice president, Medical Affairs.

About RAPTIVA
On October 27, 2003, RAPTIVA was approved by the FDA for the treatment of moderate-to-severe plaque psoriasis in adults age 18 or older who are candidates for systemic therapy or phototherapy. The recommended dose of RAPTIVA is a single 0.7 mg/kg conditioning dose followed by weekly subcutaneous doses of 1 mg/kg. A humanized therapeutic antibody, RAPTIVA is designed to selectively and reversibly block the activation, trafficking and reactivation of T-cells that lead to the development of psoriasis symptoms. In clinical studies, RAPTIVA demonstrated a rapid onset of action in the reduction of symptoms associated with psoriasis, in some patients within four weeks of initiating treatment. More than 3,000 patients have been treated with RAPTIVA to date, creating the largest existing database of patients treated with a biologic therapy for psoriasis. Over 200 patients have been treated with RAPTIVA for over one year in an open-label, continuous treatment study.

Common adverse events in clinical trials that occurred at least two percent more frequently in RAPTIVA patients than in placebo included headache, infection (mostly upper respiratory infections), chills, nausea, pain, myalgia (muscle pain), flu syndrome, fever, back pain, and acne. Five of these events (headache, chills, fever, nausea and myalgia) were predominantly acute adverse events and were principally seen following the first two injections of RAPTIVA. For the third and subsequent doses, the incidence of acute adverse events was similar between the RAPTIVA and placebo groups. Less than one percent of patients were discontinued from treatment due to acute adverse events.

RAPTIVA is an immunosuppressive agent and has the potential to increase the risk of infection and reactivate latent, chronic infections. Many immunosuppressive agents have the potential to increase the risk of malignancy. The role of RAPTIVA in the development of malignancies is not known. Serious adverse events occurring in clinical studies with RAPTIVA were serious infections (0.4 percent in RAPTIVA vs. 0.1 percent in placebo), malignancy (the overall incidence of malignancies of any kind was 1.8 per 100 patient-years for RAPTIVA-treated patients compared with 1.6 per 100 patient-years for placebo-treated patients), thrombocytopenia (0.3 percent RAPTIVA vs. 0.0 percent placebo), and worsening of psoriasis, typically upon discontinuation (0.7 percent in RAPTIVA vs. 0.0 percent in placebo). Physicians should follow patients for signs and symptoms of thrombocytopenia; platelet monitoring is recommended. Patients taking RAPTIVA should not get vaccines.

For full prescribing information, visit http://www.gene.com or call 1-877-RAPTIVA. For more information on RAPTIVA including information on comprehensive support services, visit http://www.RAPTIVA.com or call 1-877-RAPTIVA.

About Psoriasis
Psoriasis occurs when new skin cell growth rapidly accelerates, resulting in thick, red, scaly, inflamed patches on the skin surface. Psoriasis affects approximately 4.5 million Americans. Plaque psoriasis, the most common form of the disease, is characterized by inflamed patches of skin ("lesions") topped with silvery white scales. Psoriasis can be limited to a few spots or involve extensive areas of the body, appearing most commonly on the scalp, knees, elbows and trunk. Although it is highly visible, psoriasis is not a contagious disease. While there are a number of medications that may help control the symptoms of psoriasis, there is currently no cure. For more information on psoriasis, log onto http://www.allaboutpsoriasis.com or visit the National Psoriasis Foundation's Web site at http://www.psoriasis.org.

About Genentech
Genentech is a leading biotechnology company that discovers, develops, manufactures and commercializes biotherapeutics for significant unmet medical needs. Sixteen of the currently approved biotechnology products originated from or are based on Genentech science. Genentech manufactures and commercializes 12 biotechnology products in the United States. The company has headquarters in South San Francisco, California and is traded on the New York Stock Exchange under the symbol DNA. For additional information about the company, please visit http://www.gene.com.

About XOMA
XOMA develops and manufactures antibody and other protein-based biopharmaceuticals for disease targets that include immunological and inflammatory disorders, cancer and infectious diseases. XOMA's programs include collaborations: with Genentech, Inc. on the RAPTIVA antibody for psoriasis (FDA approval), psoriatic arthritis (Phase II) and other indications; and with Millennium Pharmaceuticals, Inc. on a recombinant protein, CAB-2 for vascular inflammation (preclinical). Earlier-stage development programs focus on antibodies and other compounds developed by XOMA for the treatment of acne (Phase I), cancer and retinopathies. For more information about XOMA's pipeline and activities, please visit XOMA's website at http://www.xoma.com.

Regarding XOMA:

Statements made in this news release related to the clinical benefit and usage of RAPTIVA™, or that otherwise relate to future periods, are forward looking statements within the meaning of Section 27A of the Securities Act of 1933 and Section 21E of the Securities Exchange Act of 1934. These statements are based on assumptions that may not prove accurate. Actual results could differ materially from those anticipated due to certain risks inherent in the biotechnology industry and for companies engaged in the development of new products in a regulated market. These risks include those related to safety and efficacy of the product (including the product's ability to remain safe and efficacious in the long term); market acceptance of and demand for the product (including analysis and interpretation by physicians and others of scientific data); competition; and pricing of and reimbursement for the product. These risks are discussed in XOMA's most recent annual reports on Form 10-K and in their other SEC filings. Consider such risks carefully in evaluating XOMA's prospects.

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Audio News Release
An audio news release on RAPTIVA is also available on Newstream.com.