Rituxan Phase II Data in Patients with Relapsing-Remitting Multiple Sclerosis Presented at the American Academy of Neurology

-- Rituxan Significantly Reduced Signs of Disease Activity as Measured by MRI and Relapse --

Boston - Genentech, Inc. (NYSE: DNA) and Biogen Idec, Inc. (Nasdaq: BIIB) announced that positive data from a Phase II clinical study of Rituxan® (rituximab) in patients with relapsing-remitting multiple sclerosis (RRMS) were presented today at the American Academy of Neurology annual meeting held in Boston. Rituxan is a therapeutic antibody that targets and selectively depletes CD20-positive B-cells.

"There remains a great need for safe and effective treatments for patients with RRMS"said Stephen Hauser, MD, Professor and Chair, Department of Neurology, University of California, San Francisco. "These Phase II results are very encouraging and suggest B-cells play a key role in MS. They also lend support to the concept that selective targeting of B-cells may be an important approach to treating this debilitating disease"

In this Phase II double-blind, placebo-controlled study that evaluated the safety and efficacy of Rituxan in adult patients with RRMS, 104 patients were randomized to receive either a single treatment course of Rituxan (two infusions separated by two weeks) or placebo. The primary endpoint was defined as the total number of gadolinium-enhancing T1 lesions at weeks 12, 16, 20 and 24, as measured by serial MRI scans of the brain. The total number of gadolinium lesions at weeks 12, 16, 20 and 24 was statistically significantly reduced in patients receiving Rituxan compared to those receiving placebo . At week 24, the total cumulative mean number of gadolinium lesions per patient was reduced by 91 percent, to 0.5 in the Rituxan-treated group from 5.5 in the placebo group.

In addition, the proportion of patients with relapses over 24 weeks in the Rituxan-treated arm was 14.5 percent compared to 34.3 percent in the placebo arm (58 percent relative reduction) (p = 0.0238).

With the exception of infusion associated adverse events, the percentage of patients with overall adverse events and serious adverse events were comparable between the two treatment groups during this 24-week period (97.1 percent of patients in both treatment groups experienced an adverse event and 10.1 percent of Rituxan-treated patients compared with 14.3 percent of placebo-treated patients experienced a serious adverse event). There were more first infusion-associated adverse events in Rituxan-treated patients (78.3 percent compared to 40.0 percent in placebo-treated patients), the majority ( 95 percent) were mild to moderate in severity and managed with appropriate medical intervention. The second infusion associated adverse events were 20.9 percent in Rituxan-treated patients versus 40.0 percent in placebo-treated patients. The overall percent of patients with infection were comparable in Rituxan-treated patients (65.2 percent) and placebo-treated patients (62.9 percent). Efficacy and safety data in this study will be collected and analyzed through 48 weeks.