SEBIVO(R) (telbivudine) Recommended for Approval in European Union as a new Treatment for Patients with Chronic Hepatitis B

CAMBRIDGE, Mass., Feb. 23  /PRNewswire-FirstCall/ -- Idenix Pharmaceuticals, Inc. (NASDAQ:IDIX) today announced the adoption of a positive opinion by the European Medicines Agency's (EMEA) Committee for Medicinal Products for Human Use (CHMP), recommending granting of marketing authorization of SEBIVO(R) (telbivudine), a once-a-day tablet taken with or without food, for the treatment of chronic hepatitis B infection in adult patients.  The CHMP's recommendations are advisory but the European Commission has historically followed them and the company expects a final decision to be issued within three months.

"Chronic hepatitis B is a very serious disease affecting more than 350 million people worldwide and a growing public health problem in Europe," said Jean-Pierre Sommadossi, Idenix's chairman and chief executive officer. "We are assembling a strong commercial team in Europe and look forward to working with Novartis to make SEBIVO available to European patients as soon as possible after it is formally approved."

The positive opinion from CHMP follows earlier approvals in the United States, where the drug is being marketed as TYZEKA(R) (telbivudine) 600 mg tablets; Canada; Switzerland and various other countries in Asia and Latin America. An application for marketing approval is pending with the Chinese health authority.  Regulatory submissions have been based primarily on one- year data from the GLOBE study, the largest worldwide registration trial including both HBeAg-positive and HBeAg-negative patients with chronic hepatitis B ever conducted.

Data from the pivotal phase III clinical trial, known as the GLOBE study, compared telbivudine to lamivudine in 1,367 patients. The primary efficacy endpoint of the GLOBE study was therapeutic response at one year, a composite endpoint coupling viral suppression (serum HBV DNA suppression below 100,000 copies/mL) with either improved liver disease markers (ALT normalization) or loss of detectable hepatitis B e-antigen (HBeAg). In HBeAg-positive patients, therapeutic response was 75 percent (n=345/458) among patients treated with SEBIVO and 67 percent (n=310/463) for those patients treated with lamivudine, while the response for HBeAg-negative patients after one year was 75 percent (n=167/222) vs. 77 percent (n=173/224), respectively. In the GLOBE study, patients who achieved non-detectable HBV DNA levels at 24 weeks were more likely to undergo e-antigen seroconversion, achieve undetectable levels of HBV DNA, normalize ALT, and minimize resistance at one year.

In clinical studies SEBIVO was generally well tolerated with most adverse experiences classified as mild or moderate in severity. Common (greater than or equal to 1/100,