Genentech Issues Dear Healthcare Provider Letter Regarding a Reported Case of PML in a Raptiva Patient

Genentech, Inc. (NYSE:DNA) announced today that the company has issued a Dear Healthcare Provider letter to inform potential prescribers of a case of progressive multifocal leukoencephalopathy (PML) in a 70-year old patient who had received Raptiva^® (efalizumab) for more than four years for treatment of chronic plaque psoriasis. The company will work with the U.S. Food and Drug Administration (FDA) to update the prescribing information for Raptiva and determine if further action is needed.

"We believe it is important for healthcare providers to be aware of this case of PML in a patient receiving Raptiva and are working with the FDA to ensure that this information is communicated appropriately to physicians so that physicians and their patients can make informed treatment decisions," said Hal Barron, M.D., Genentech senior vice president, development and chief medical officer.

The case was recently reported to the company in late September as part of Genentech’s ongoing safety monitoring and surveillance program. Based on the medical information available to date, Raptiva may have had a contributory role in the development of PML in this patient. There are no other cases of confirmed PML in patients treated with Raptiva. There has been a report of a 62-year old patient treated with Raptiva who developed progressive neurologic symptoms and died of unknown cause. Information about this other case is also included in the Dear Healthcare Provider letter issued today.

Patients who are currently on Raptiva therapy or considering Raptiva should discuss the benefits and risks of Raptiva with their physicians. As described in the Raptiva package insert, some patients have had severe worsening or new forms of psoriasis while taking Raptiva or after stopping Raptiva. It is important for patients not to change or stop treatment without first talking with their physician.

The Dear Healthcare Provider letter has been posted to the Genentech web site and is available along with the current package insert including Raptiva safety information by clicking the Raptiva link at http://www.gene.com/gene/products.

About PML

PML is a rare, progressive, demyelinating disease of the central nervous system that usually leads to death or severe disability. PML is caused by activation of the John Cunningham, (JC) virus. JC virus resides in latent form in up to 80 percent of healthy adults, typically only causing PML in immunocompromised patients. The factors leading to activation of the latent infection are not fully understood, though abnormalities in T-cells may be important for reactivation and PML. PML has been reported in the published literature in HIV-positive patients, as well as immunosuppressed cancer patients (including patients with hematologic malignancies), organ transplant recipients, and patients with autoimmune diseases. There are no known interventions that can reliably prevent or adequately treat PML.

About Psoriasis

Psoriasis occurs when new skin cells grow abnormally, resulting in thick, red, and scaly, inflamed patches. Plaque psoriasis, the most common form of the disease, affects approximately 2.3 million Americans and 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 currently is no known cure.

About Raptiva

Raptiva® (efalizumab) is a humanized therapeutic antibody designed to selectively and reversibly block the activation, reactivation and trafficking of T-cells that lead to the development of psoriasis. In October 2003, Raptiva received U.S. Food and Drug Administration approval for the treatment of chronic moderate-to-severe plaque psoriasis in adults 18 years or older who are candidates for systemic therapy or phototherapy. Raptiva can be self-administered by patients as a single dose, once-weekly, subcutaneous injection after proper training by a healthcare professional.

Important Safety Information

The most common adverse reactions associated with Raptiva were a symptom complex that included headache, chills, fever, nausea, and myalgia within 48 hours following the first two injections. These events were largely mild to moderate when a first dose of 0.7 mg/kg was given. Less than one percent of patients discontinued Raptiva treatment because of these adverse events.

The most serious adverse reactions observed during treatment with Raptiva were serious infections, malignancies, immune-mediated thrombocytopenia, immune-mediated hemolytic anemia, arthritis events, and psoriasis worsening and variants. Serious infections and immune-mediated thrombocytopenia have been reported during post-marketing surveillance. Physicians should follow patients for signs and symptoms of thrombocytopenia; platelet monitoring is recommended. Acellular, live, and live-attenuated vaccines should not be administered during Raptiva treatment.

For full prescribing information, please visit http://www.RAPTIVA.com or call 877-RAPTIVA.

About Genentech

Founded more than 30 years ago, 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 and licenses several additional products to other companies. The company has headquarters in South San Francisco, California and is listed on the New York Stock Exchange under the symbol DNA. For additional information about the company, please visit http://www.gene.com.