Serono, Inc. and Pfizer Inc, co-promoters of Rebif (interferon beta-1a) in the US, announced that the U.S. Food and Drug Administration (FDA) has approved additional efficacy and product stability information for Rebif. The new label changes reflect the treatment's efficacy and convenience in treating multiple sclerosis.

The new labeling changes include an update to the Clinical Studies section to add 48-week data from the Evidence study. This head-to-head study of Rebif and Avonex (interferon beta-1a) compared the proportion of MS patients treated with Rebif or Avonex who were relapse free after 24 weeks (primary end point) and 48 weeks. The label expansion will now reflect that, "Patients treated with Rebif 44 mcg sc tiw were more likely to remain relapse free at 24 and 48 weeks than were patients treated with Avonex 30 mcg im qw."

"Serono and Pfizer are pleased with the FDA's approval of the new label changes for Rebif. The label expansion reflects additional scientific data demonstrating Rebif's clinical superiority over Avonex at reducing frequency of relapses in patients with relapsing remitting MS at both 24 and 48 weeks," said Gordon Francis, M.D., vice president, Neurology Clinical Development Unit, Serono, Inc.

Furthermore, the FDA also approved label changes related to Rebif temporary storage at room temperature. This change enhances Rebif's ease-of-use for people who are currently taking the therapy to treat their MS. The label expansion will include that, "Rebif may be stored at or below 25 degrees C/77 degrees F for up to 30 days and away from heat or light" and will be reflected in the Stability and Storage section. The same room temperature storage conditions were already allowed in the other countries where Rebif is approved.

"With Rebif's temporary room temperature labeling, we are building on our commitment to offer consumers not only a highly efficacious MS treatment, but also the added convenience that patients seek," said Deborah Brown, Executive Vice President, Neurology, Serono, Inc.

Christy Demory, an attorney from North Carolina, who takes Rebif, welcomed the change. "Between family and work, I am always on the go and sometimes need to carry Rebif with me to my office or on an overnight outing or when I travel, so it's great to have the flexibility of leaving it out at room temperature," she said. "It's one less thing I have to think about."

A revised patient Medication Guide will also be available that reflects new storage and needle disposal information.

The expanded Rebif label now contains data from the head-to-head Evidence study of 677 patients with relapsing remitting MS. The study compared the proportion of MS patients treated with either Rebif or Avonex who were relapse-free after 24 weeks (primary endpoint) and 48 weeks. The data showed that 75 per cent of patients who received Rebif (44 mcg administered subcutaneously, three times weekly) did not have a relapse after 24 weeks of treatment compared to 63 per cent of patients treated with Avonex (30 mcg administered intramuscularly, once weekly) (p<0.001). The improvement was sustained at 48 weeks at which point 62 per cent of Rebif patients were relapse free as compared to 52 per cent of Avonex patients (p=0.009).

Magnetic Resource Imaging (MRI) was used to assess brain lesions periodically throughout the 48-week study. Patients treated with Rebif had fewer active lesions per MRI scan for all activity measures with effects seen within 2-3 months of starting treatment. There was an approximate one-third relative difference in favor of Rebif and treatment effects were maintained over 48 weeks for measures of lesion activity. The exact relationship between MRI findings and clinical outcomes for patients is unknown.

Rebif (interferon beta-1a) is a disease-modifying drug used to treat relapsing forms of multiple sclerosis and is similar to the interferon beta protein produced by the human body. Interferon helps modulate the body's immune system, fights disease and reduces inflammation.

Rebif has been proven to slow the course of relapsing forms of multiple sclerosis. In clinical studies, Rebif 44 mcg administered three times a week by subcutaneous injection has been shown to slow progression of disability and reduce the frequency of relapses in relapsing-remitting MS. Additionally, use of Rebif was shown to statistically significantly reduce the number of active brain lesions and T2 lesion area as measured on MRI. The exact relationship between MRI findings and clinical status of patients is unknown.