Data From Omnitarg Clinical Program Presented at American Society of Clinical Oncology Meeting

ORLANDO, Fla., May 15 /PRNewswire-FirstCall/ -- Genentech, Inc. today presented results from Phase II studies evaluating Omnitarg(TM) (pertuzumab), an investigational targeted therapy known as a Human Epidermal Receptor (HER) dimerization inhibitor. The studies showed Omnitarg had limited activity as a single agent in ovarian, breast and prostate cancers. The studies were presented at the 41st Annual Meeting of the American Society of Clinical Oncology (ASCO).

"The results of these early studies of Omnitarg, studied as a single agent, did not meet our expectations," said Hal Barron, M.D., Genentech's senior vice president, development, and chief medical officer. "However, the results of the study in ovarian cancer indicate that further study of Omnitarg in this setting is warranted. We are committed to further exploring Omnitarg and are currently enrolling patients in an additional Phase II study of Omnitarg in combination with chemotherapy in advanced ovarian cancer."

Clinical Activity of Omnitarg in Advanced, Refractory or Recurrent Ovarian Cancer (OC), and the Role of HER2 Activation Status (Abstract #5051 - Sunday, May 15, 2005 2:00 p.m. EDT)

The study by Michael Gordon, M.D., of the University of Arizona Cancer Center, evaluated tumor response rates in patients with advanced, refractory or recurrent ovarian cancer. The trial enrolled 65 patients, of which 60 were evaluable for analysis at the time of presentation. Median age of patients was 59 years and median number of prior chemotherapy regimens was five. Omnitarg was administered intravenously as a single agent, with an 840 mg initial dose followed by 420 mg every three weeks thereafter. Partial responses were observed in 3 percent of the patients (2/60), and stable disease of greater than six months or a drop in CA125 was observed in an additional 12 percent of patients (7/60). Grade 1-3 diarrhea was the most common adverse event reported (57 percent, 34/60). The investigators concluded that the study results suggest that Omnitarg may have activity in ovarian cancer.

Open Label, Randomized, Phase II Study of Omnitarg in Patients with Metastatic Breast Cancer (MBC) with Low Expression of HER2 (Abstract #3068 - Sunday, May 15, 2005 8:00 a.m. EDT)

Javier Cortes, M.D., from Hospital Vall d'Hebron in Barcelona, Spain, presented data from a Phase II study of Omnitarg in 78 evaluable patients with metastatic breast cancer whose tumors were HER2-negative and who had previous treatment with an anthracycline and two or fewer courses of chemotherapy. In this study, the primary endpoint was response rate and secondary endpoints were rate of stable disease (SD), toxicity profile and pharmacokinetics (PK) profile. Patients were randomized to receive Omnitarg intravenously every three weeks either at 420 mg with a loading dose of 840 mg (Arm A) or at 1050 mg (Arm B). Overall, 8 percent (6/78) of patients experienced a partial response or stable disease for more than six months.

A preliminary assessment of safety showed that the most frequent adverse events (all grades) were diarrhea (59 percent, 46/78), fatigue (37 percent, 29/78), nausea (32 percent, 25/78), and vomiting (23 percent, 18/78). Drops in left ventricular ejection fraction (LVEF) of 10 percent or greater were observed in seven patients, of which six were asymptomatic. There was one case of congestive heart failure in the study. The author concluded that limited activity was seen in this study of Omnitarg in metastatic breast cancer, and a combination study of Omnitarg with either chemotherapy or a hormone treatment, or a patient selection strategy, may warrant future investigation.

Efficacy and Safety of Single Agent Omnitarg, a HER Dimerization Inhibitor, in Hormone Refractory Prostate Cancer after Failure of Taxane-based Therapy (Abstract #4624 - Saturday, May 14, 2005 8:00 a.m. EDT)

David Agus, M.D., of Cedars Sinai Medical Center in Los Angeles, California, reported on a study of Omnitarg in 41 patients with prostate cancer who had progressed on or after prior hormonal and taxane-based therapies. Patients were treated intravenously with a loading dose of 840 mg of Omnitarg followed by 420 mg every three weeks. Primary endpoints of the study were best overall response, time to progression and safety. Response was assessed by CT scan, bone scan and prostate specific antigen (PSA) after 4, 8 and 12 cycles of treatment. No PSA or objective radiographic responses to Omnitarg were observed. Stable disease beyond four cycles was observed in 12 percent (5/41) of patients. Cancer progression at or prior to four cycles was observed in 44 percent (18/41) of patients and 44 percent (18/41) of patients discontinued therapy for other reasons. Grade 1-3 diarrhea was observed for 61 percent of patients (25/41).

An Open Label, Phase II, Multicenter Study to Evaluate the Efficacy and Safety of Omnitarg in Chemotherapy-Naive Patients with Hormone Refractory Prostate Cancer (Abstract #4609 - Saturday, May 14, 2005 8:00 a.m. EDT)

Johann de Bono, M.D., Ph.D., from Royal Marsden Hospital in Surrey, England, reported on a single-agent study of Omnitarg in patients with hormone refractory prostate cancer whose cancer was progressing and who had not previously received chemotherapy. Omnitarg was administered intravenously once every three weeks at 420 mg with loading doses the first week of 840 mg and 1050 mg administered in two equally divided cohorts. Forty-six patients were evaluable at the time of an interim analysis. The primary endpoint of the study was PSA response rate after 24 weeks. Secondary endpoints were safety, overall response rate, time to tumor progression and overall survival. No PSA responses were observed and median time to progession was five weeks. One unconfirmed 75 percent decrease in PSA was reported. The most common adverse event reported in the study was Grade 1/2 diarrhea (46 percent, 21/46). No differences in toxicity were observed between the 840 mg and 1050 mg dose levels.

About Omnitarg

Omnitarg is a monoclonal antibody and the first in a new class of agents know as HER dimerization inhibitors (HDIs). It was developed to bind to the HER2 receptor and block the interaction between HER2 and other HER family members (HER1/EGFR, HER2, HER3, and HER4). Inhibiting receptor dimerization prevents the activation of the HER signaling pathway, which may play a role in cancer proliferation. Omnitarg is designed to target tumors that have normal, rather than overexpressed, levels of the HER2 protein.

About Genentech BioOncology

Genentech is committed to changing the way cancer is treated by establishing a broad oncology portfolio of innovative, targeted therapies with the goal of improving patients' lives. The company is the leading provider of anti-tumor therapeutics in the United States. Genentech is leading clinical development programs for Rituxan(R) (Rituximab), Herceptin(R) (Trastuzumab), Avastin(TM) (bevacizumab) and Tarceva(TM) (erlotinib), and markets all four products in the United States alone (Avastin and Herceptin), with Biogen Idec Inc. (Rituxan) or with OSI Pharmaceuticals (Tarceva). Genentech has licensed Rituxan, Herceptin, and Avastin, and OSI Pharmaceuticals has licensed Tarceva to Roche for sale by the Roche Group outside of the United States.

The company has a robust pipeline of potential oncology therapies with a focus on four key areas: angiogenesis, apoptosis (i.e. programmed cell death), the HER pathway and B-cell biology. Potential oncology therapies directed at the HER pathway include a therapeutic antibody currently in Phase II trials. Also in early development are a small molecule directed at the hedgehog pathway, a soluble human protein targeting apoptosis and a humanized anti-CD20 antibody for hematology/oncology indications.

Genentech is a leading biotechnology company that discovers, develops, manufactures and commercializes biotherapeutics for significant unmet medical needs. A considerable number of the currently approved biotechnology products originated from, or are based on, Genentech science. Genentech manufactures and commercializes multiple biotechnology products directly in the United States and licenses several additional products to other companies. The company has headquarters in South San Francisco, Calif., 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/ .

Roche in Oncology

The Roche Group, including its members Genentech in the United States and Chugai in Japan, is the world's leading provider of cancer care products, including anti-cancer treatments, supportive care products and diagnostics. Its oncology business includes an unprecedented five products proven to provide survival benefit in different major tumour indications: Avastin, Herceptin, and Xeloda in advanced-stage breast cancer, Herceptin in early- stage HER2-positive breast cancer, MabThera in non-Hodgkin's lymphoma, Avastin and Xeloda in colorectal cancer, Avastin and Tarceva in non-small cell lung cancer and Tarceva in pancreatic cancer.

In addition to these anti-cancer agents, the Roche oncology portfolio includes a comprehensive collection of medicines that can help improve the quality of life of cancer patients: Bondronat (for prevention of skeletal events in patients with breast cancer and bone metastases, hypercalcaemia of malignancy), Kytril (for chemotherapy and radiotherapy-induced nausea and vomiting), Neupogen (for cancer-related neutropenia), and NeoRecormon (for anaemia in various cancer settings). CERA is the most recent demonstration of Roche's commitment to anaemia management. Other oncology products include Furtulon (for colorectal cancer) and Roferon-A (for hairy cell and chronic myeloid leukaemia, Kaposi's sarcoma, malignant melanoma, renal cell carcinoma). The Roche Group's cancer medicines generated sales of more than 7.7 billion Swiss francs in 2004.

In addition to the medicines, Roche is developing new diagnostic tests that will have a significant impact on disease management for cancer patients in the future. With a broad portfolio of tumour markers for prostate, colorectal, liver, ovarian, breast, stomach, pancreas and lung cancer, as well as a range of molecular oncology tests, Roche will continue to be the leader in providing cancer-focused treatments and diagnostics.

The unmatched Roche oncology portfolio as well as an extensive external innovation base through collaborations with companies and academia is what makes it possible for Roche to provide more effective cancer therapies. In the United States Herceptin, MabThera (Rituxan), Avastin and Tarceva are marketed either by Genentech alone or together with its partners Biogen Idec Inc. (MabThera) and OSI (Tarceva). Outside of the United States, Roche and its Japanese partner Chugai are responsible for the marketing of these medicines.

For full prescribing information, including Boxed Warnings for Avastin, Rituxan and Herceptin, or for Tarceva full prescribing information, please call 800-821-8590 or visit http://www.gene.com/ .

Genentech Contacts: Media: Kristina Becker (650) 467-6450 Investors: Kathee Littrell (650) 225-1034 Advocacy: Cheya Pope (650) 225-6334 Roche Media Line: +41 61 688 8888