ONE-YEAR DATA FROM PHASE III TRIAL SHOW THAT NEW FORMULATION OF REBIF® OFFERS SUBSTANTIAL IMPROVEMENT IN TOLERABILITY AND IMMUNOGENICITY PROFILES:
Madrid, Spain, September 28, 2006 - Serono (virt-x: SEO and NYSE: SRA) announced today data from an ongoing two-year (96 weeks) Phase IIIb trial show that the new formulation of Rebif® (interferon beta-1a) 44 mcg subcutaneously (sc) three times weekly (tiw) for the treatment of relapsing forms of multiple sclerosis (MS) offers substantial improvement in tolerability and reduction in antibody formation observed at one year (48 weeks), compared with historical data from patients. Historical data for the currently available formulation of Rebif® is the EVIDENCE study. These data are presented today at a satellite symposium at the 22nd Congress of the European Committee for Treatment and Research in Multiple Sclerosis (ECTRIMS) in Madrid, Spain.

“These results are promising news for patients with multiple sclerosis," said Prof Per Soelberg Sørensen, from the Danish MS Research Center, Copenhagen University Hospital, Rigshospitalet and an investigator of the trial.

“If approved the new formulation of Rebif® potentially represents an improvement in the treatment of patients with multiple sclerosis.”

The incidence of injection site reactions with the new formulation of Rebif® at 48 weeks was nearly three-fold less than in the EVIDENCE study (29.6% versus 83.8%). Injection site reactions are one of the reasons why some patients discontinue MS treatment. Treatment enhancements resulting in a decrease of injection site reactions are usually associated with improved compliance and adherence to treatment.

The primary endpoint of the study is the proportion of neutralizing antibody positive patients at the last assessment. At 48 weeks, the data showed that 13.9% of patients treated with the new formulation of Rebif® were neutralizing antibody positive. In the EVIDENCE study at 48 weeks, 24.4% of the patients were positive. Persistent neutralizing antibodies were detected in 2.5% of the patients treated with the new formulation of Rebif® at 48 weeks. In the EVIDENCE study at 48 weeks, the rate of persistent neutralizing antibodies observed was 14.3%.

“The new formulation of Rebif® has been developed by an innovative approach, using state-of-the-art technologies, with a major focus on the molecule’s structural and functional integrity”, said Franck Latrille, Senior Executive Vice President Global Product Development at Serono. “Based on the improvements in tolerability and immunogenicity, the new formulation of Rebif® could lead to an improved benefit-to-risk profile”.

The new formulation of Rebif® is the latest of many product developments from Serono to continually enhance the convenience and tolerability of Rebif®. Other enhancements have included the Rebiject II auto-injector to facilitate injections; a 29 gauge-5 bevel needle pre-filled syringe, the thinnest needle in a ready-to-use pre-filled syringe for the treatment of MS; and a titration pack designed to make starting on Rebif® therapy easier and more convenient. The new formulation of Rebif® is currently under regulatory review by the European Medicines Agency, the US Food and Drug Administration and other healthcare authorities.

The results presented today are the 48-week results from a 96-week, Phase IIIb, multicenter, single-arm, open-label study evaluating the safety and immunogenicity of the new formulation of Rebif® 44 mcg sc tiw in 260 patients with relapsing forms of MS. The primary objective of the study was to compare the antigenicity of new formulation Rebif to historical data.

About Rebif®

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, fight disease and reduce inflammation.

Rebif®, which was approved in Europe in 1998 and in the US in 2002, is registered in more than 80 countries worldwide. In the United States, Rebif® is co-marketed by Serono, Inc. and Pfizer Inc. Rebif® has been proven to delay the progression of disability, reduce the frequency of relapses and reduce MRI lesion activity and area1. Rebif® is available in a 22 mcg and 44 mcg ready-to-use pre-filled syringe and a titration pack, and can be stored at room temperature for up to 30 days if a refrigerator is not available.
Most commonly reported side effects are injection site disorders, flu-like symptoms, elevation of liver enzymes and blood cell abnormalities. Patients, especially those with depression, seizure disorders, or liver problems, should discuss treatment with Rebif® with their doctors.

1 The exact relationship between MRI findings and the clinical status of patients is unknown......MORE