Tuesday, Sep 17, 2002

Genentech and XOMA Announce Phase III Study with Raptiva(TM) Achieves Primary Efficacy Endpoint

South San Francisco, Calif. -- September 17, 2002 --

Genentech, Inc. (NYSE: DNA) and XOMA Ltd. (Nasdaq: XOMA) today announced that a randomized Phase III study with RaptivaTM (efalizumab), an investigational therapy for moderate-to-severe psoriasis, achieved its primary efficacy endpoint.  The primary endpoint of the study was to compare the percentage of patients who achieved 75 percent or greater improvement in Psoriasis Area and Severity Index (PASI) scores (PASI 75) after 12 weeks of Raptiva therapy with patients receiving placebo.  Genentech and XOMA plan to include this data as part of a Biologics License Application (BLA) to be filed with the U.S. Food and Drug Administration (FDA).

“The data from this trial, conducted with Genentech material, are consistent with data obtained from previous Phase III studies with Raptiva that used both Genentech and XOMA material,” said Hal Barron, M.D., FACC, Genentech’s vice president, Medical Affairs.  “These results provide additional support for Raptiva as a therapy for patients with moderate-to-severe psoriasis.  Genentech and XOMA will be discussing the data with the FDA in conjunction with plans to file the BLA by the end of 2002.”

Serono S.A. (Virt-x: SEO and NYSE: SRA) has an exclusive license to market Raptiva internationally outside of the United States, Japan and certain other Asian countries, and plans to file Raptiva with European authorities in the first quarter of 2003.

The FDA requested that the current Phase III study be completed before the filing of a BLA for Raptiva after results from a pharmacokinetic study suggested that Genentech-produced Raptiva material showed a slightly higher serum concentration than XOMA-produced Raptiva material.  Previous Phase III trials were conducted with both Genentech and XOMA material.

I'm particularly pleased with the positive results from this latest Phase III study, because they enable us to move closer towards the goal of providing a safe and effective psoriasis therapy to patients who need better treatment options,” said Jack Castello, XOMA’s chief executive officer.

Genentech and XOMA will present the data from this study at an upcoming medical meeting.

This double-blind, placebo-controlled, multicenter efficacy study enrolled 556 patients with moderate-to-severe plaque psoriasis who were randomized in a 2 to 1 ratio to receive 12 weekly subcutaneous injections of 1 mg/kg of Raptiva or placebo.  The trial also measured several secondary endpoints at 12 weeks, including the Overall Lesion Severity (OLS) scale, the percentage of patients achieving 50 percent or greater improvement in PASI scores (PASI 50) and the percentage of PASI improvement over time.  As was the case with the primary endpoint, the secondary endpoints were consistent with data obtained from previous Phase III Raptiva studies.

The safety profile in this study was similar to previous Raptiva trials conducted with both Genentech and XOMA material.  Adverse events that occurred more often in the Raptiva arm included mild-to-moderate headache, general aches/pains, chills, nausea and fever.


About Raptiva

Raptiva is a targeted T-cell modulator that is designed to inhibit the binding of T-cells to other cell types and targets three key processes in the cascade of events that lead to psoriasis. These processes are: (1) binding of T-cells through interactions with adhesion molecules on the endothelial cell surface; (2) migration of T-cells into the skin; and (3) activation of T-cells, all of which may be linked to the abnormal growth of skin cells and the painful, elevated scaly patches of skin (lesions) typical among psoriasis sufferers. 

Raptiva is being developed in the U.S. through a partnership between Genentech and XOMA for the treatment of moderate-to-severe plaque psoriasis.  Last month, Genentech and Serono S.A. entered into an agreement through which Serono receives an exclusive license to market Raptiva outside of the U.S., Japan and certain other Asian countries.


About Genentech

Genentech is a leading biotechnology company that discovers, develops, manufactures and commercializes biotherapeutics for significant unmet medical needs.  Fifteen of the currently approved biotechnology products originated from or are based on Genentech science.  Genentech manufactures and commercializes ten biotechnology products directly 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.


About XOMA

XOMA develops and manufactures antibody and other protein biopharmaceuticals for disease targets that include cancer, immunological and inflammatory disorders, and infectious diseases.  XOMA's programs include collaborations with: Genentech, Inc. on the Raptiva™ antibody for psoriasis (Phase III), rheumatoid arthritis (Phase II) and other indications; Onyx Pharmaceuticals, Inc. to develop and manufacture its ONYX-015 product for various cancers (Phase II and III); Baxter Healthcare Corporation to develop NEUPREX™ (rBPI-21) for Crohn's disease (Phase II) and other indications; and with Millennium Pharmaceuticals, Inc. on two biotherapeutic agents for certain vascular inflammation indications (preclinical). Earlier-stage development programs include compounds to treat cancer, retinopathies, autoimmune diseases and infections. For more information about XOMA's pipeline and activities, please visit XOMA's website at http://www.xoma.com.

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The statements made in this press release relating to the regulatory authority filing time frames for Raptiva in the U.S. and Europe are forward-looking and the actual filing time frames could differ materially.  Among other things, the regulatory filings in the U.S. or Europe could be delayed by unexpected safety or efficacy issues, manufacturing issues, additional time requirements for data analysis, preparation of the BLA or the regulatory filing in Europe, discussions with regulatory authorities, or the need for additional clinical studies.


Statements made in this news release related to the timing of regulatory approval, submission of regulatory filings, progress of clinical trials and collaborative arrangements, 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, efficacy and comparability of the products being studied; action, inaction or delay by the Food and Drug Administration; analysis and interpretation of scientific data; changes in the status of existing collaborative relationships; the ability of collaborators to meet their obligations and market demand for products, as well as those factors described in the preceding paragraph.  These risks are discussed in XOMA’s most recent annual report on Form 10K and in other SEC filings.  Consider such risks carefully in evaluating XOMA’s prospects.