Study Shows that High-Dose, High-Frequency Interferon Produces no Additional Benefit on Efficacy Compared to AVONEX(R) (interferon beta-1a) in Patients with Relapsing-Remitting Multiple Sclerosis (RRMS)

Results of a phase IV, open label, head-to-head study of intramuscular AVONEX and high-dose, high-frequency subcutaneous Rebif(R) (interferon beta-1a) provide clinical evidence that the two drugs show similar efficacy over 18 to 30 months of continued therapy in patients with relapsing-remitting multiple sclerosis (RRMS). These data are published in the April 2008 issue of the Current Medical Research and Opinion journal.

CAMBRIDGE, Mass. (Business Wire EON) April 15, 2008 -- Results of a phase IV, open label, head-to-head study of intramuscular AVONEX and high-dose, high-frequency subcutaneous Rebif® (interferon beta-1a) provide clinical evidence that the two drugs show similar efficacy over 18 to 30 months of continued therapy in patients with relapsing-remitting multiple sclerosis (RRMS). These data are published in the April 2008 issue of the Current Medical Research and Opinion journal.

AVONEX is the only once-a-week therapy that has proven to slow disability and offers a low incidence of injection site reactions.

The Prospective and Retrospective Long-Term Observational Study of AVONEX and Rebif (PROOF), involved 217 patients with 136 completing a median of 25.9 months of AVONEX 30 mcg once weekly (n=69) and a median of 22.2 months Rebif 44 mcg three times weekly (n=67).

Led by a group of principal investigators including Dr. T. Jock Murray of Division of Neurology, Dalhousie MS Research Unit, Queen Elizabeth II Health Sciences Center, Halifax, Nova Scotia; Canada; and Dr. Alireza Minagar, Louisiana State University Health Sciences Center-Shreveport, Shreveport, Louisiana, the study provides further clinical evidence that the dose and frequency of treatment shows no advantage on delivering better efficacy.

Upon evaluation of baseline disability, Expanded Disability Status Scale (EDSS) scores showed no statistically significant differences between the two treatment groups during the prospective portion of the study, with sustained disability progression similar for both: 25.8 percent for AVONEX vs. 26.7 percent for Rebif. Additional key findings include:

• Relapse rates, MRI endpoints of brain parenchymal fraction, T1 lesion volume, T2 lesion volume, number of new/enlarging T2 lesions and gadolinium enhancing (Gd+) lesion volume and count were also comparable between both groups.
• In addition, 19 percent of patients taking Rebif tested positive for neutralizing antibodies (NAbs) at end of treatment compared with zero percent taking AVONEX.

“Given that this data shows similar efficacy between AVONEX and Rebif, physicians and patients with relapsing-remitting MS may want to consider factors that influence ease of use and adherence to treatment such as convenient administration, injection tolerability and immunogenicity when selecting therapy,” said Dr. Murray.

“These results are in accordance with a growing body of evidence from other trials that suggest that interferons show similar efficacy regardless of dose or frequency,” said Thorsten Eickenhorst, MD, vice president of Medical Affairs at Biogen Idec. “AVONEX is the only once-a-week therapy that has proven to slow disability and offers a low incidence of injection site reactions.”

AVONEX is the number one prescribed treatment for relapsing forms of multiple sclerosis (MS) worldwide, and is the only once-a-week MS therapy that is effective after the first attack. AVONEX is also proven to slow the progression of physical disability (as shown by 37 percent reduction over two years) and reduce the number of relapses. Nearly nine out of 10 patients remained fully functional after five years. AVONEX has been proven effective in clinical trials for up to three years.

This study was supported by Biogen Idec.

About AVONEX

AVONEX is the number one most prescribed treatment for relapsing forms of MS worldwide, with more than 130,000 patients on therapy. It was launched in the U.S. in 1996 and later in Europe for the treatment of relapsing forms of MS to slow the progression of disability and reduce relapses. AVONEX has been proven effective in clinical trials for up to three years. AVONEX is marketed internationally in more than 90 countries. AVONEX was the first treatment approved for patients who have their first clinical MS attack and have a brain MRI scan consistent with MS; this use was approved in Europe in 2002 and in the U.S. in 2003.

The most common side effects associated with AVONEX multiple sclerosis treatment are flu-like symptoms, including myalgia, fever, fatigue, headache, chills, nausea, vomiting, pain and asthenia.

AVONEX should be used with caution in patients with depression or other mood disorders and in patients with seizure disorders. AVONEX should not be used by pregnant women. Patients with cardiac disease should be closely monitored. Patients should also be monitored for signs of hepatic injury. Routine periodic blood chemistry and hematology tests are recommended during treatment with AVONEX. Rare cases of anaphylaxis have been reported. Please see complete prescribing information available at http://www.AVONEX.com.