European Union Approves Pegintron (Peginterferon Alfa-2b) For Hepatitis C

MADISON, NJ -- May 30, 2000 -- Schering-Plough Corporation announced that the European Union's (EU) Commission of the European Communities has granted marketing authorization to Pegintron™ (peginterferon alfa-2b) as once-weekly monotherapy for the treatment of adult patients with chronic hepatitis C. Pegintron is the first pegylated interferon approved for marketing in the world.

In clinical studies, once-weekly administration of Pegintron has been shown to be twice as active and just as well tolerated as Schering-Plough's Intron(R) A (interferon alfa-2b, recombinant) Injection, the world's largest-selling alpha interferon, administered three times weekly as monotherapy for hepatitis C.

Pegintron is a longer-acting form of Intron A that uses proprietary PEG technology developed by Enzon, Inc. of Piscataway, N.J. Schering-Plough holds an exclusive worldwide license to Pegintron. Commission approval of the centralized application for Pegintron results in a single Marketing Authorization with unified labeling that is immediately valid in all 15 EU-Member States. The Commission's decision follows the product's unanimous recommendation for approval in February 2000 by the EU's Committee for Proprietary Medicinal Products (CPMP) of the European Agency for the Evaluation of Medicinal Products (EMEA).

Pegintron will be introduced upon receiving pricing approvals, where necessary, from individual EU countries.

Pegintron is indicated as monotherapy in case of intolerance or contraindication to ribavirin for the treatment of adult patients with histologically proven chronic hepatitis C who have serum markers indicating virus replication, e.g., those patients who have elevated transaminases without liver decompensation and who are positive for serum HCV-RNA or anti-HCV.

The approved labeling in the EU for Pegintron indicates that the optimal treatment for chronic hepatitis C is considered to be the administration of a combination of interferon alfa-2b with ribavirin. The safety and efficacy of the combination of Pegintron and ribavirin has not yet been documented.

Pegintron monotherapy is administered subcutaneously at a dose of 0.5 or 1.0 mcg/kg once weekly for at least six months. In patients showing loss of HCV-RNA at six months, treatment is continued for an additional six months, i.e. for a total course of treatment of one year.

A worldwide, controlled clinical study designed to establish the activity and tolerance of Pegintron versus Intron A monotherapy was conducted in adult patients with previously untreated chronic hepatitis C and compensated liver disease. A total of 1,219 patients, who were positive for serum HCV-RNA and who had elevated liver enzymes (serum alanine aminotransferase), were treated with one of three doses of Pegintron (0.5, 1.0, 1.5 mcg/kg) administered once weekly or Intron A (3 MIU) administered three times weekly for 48 weeks. The primary efficacy endpoint of the study was sustained loss of detectable HCV-RNA at 24 weeks from the end of 48 weeks of treatment. Pegintron at all three doses studied was shown to be superior to, and as safe as, Intron A in treating all HCV genotypes.

The study results showed that sustained virologic responses were achieved in 25 percent of patients receiving Pegintron 1.0 mcg/kg and 18 percent of patients receiving Pegintron 0.5 mcg/kg, compared to 12 percent of patients receiving Intron A. In patients having genotype 2 or 3 and low viral load (<2 million copies/ml), sustained virologic responses were achieved in 62 percent of patients treated with Pegintron 1.0 mcg/kg and 58 percent of patients treated with Pegintron 0.5 mcg/kg, compared to 36 percent of patients treated with Intron A.

The demographic/disease characteristics of patients in this study were similar to those in previous Schering-Plough hepatitis C registration studies, with a majority of patients having genotype 1, the most difficult genotype to treat (70 percent genotype 1), and high viral load (74 percent HCV-RNA>2 million copies/ml).

Adverse events (AEs) for all doses of Pegintron were similar to those for Intron A. Most AEs were mild to moderate and were manageable with dose adjustment. Discontinuation of therapy due to AEs was similar for all treatment groups (6-11 percent). Dose reductions were similar for Intron A and Pegintron 0.5 mcg/kg and higher for Pegintron 1.0 and 1.5 mcg/kg (6 percent, 9 percent, 14 percent and 19 percent, respectively). The most common side effects occurring with Pegintron were "flu-like" symptoms, such as headache, fatigue, myalgia and fever, which appeared to decrease in severity as treatment continued.

Chronic hepatitis C is estimated to affect some 10 million people in major world markets. As many as 5 million Europeans (1 to 2 percent of the general population) are chronically infected with the hepatitis C virus, according to a study conducted by the World Health Organization (WHO). In Europe, chronic hepatitis C is the leading cause of chronic liver disease and the most common reason for liver transplant.

In the United States, Schering-Plough on Dec. 23, 1999, submitted a Biologics License Application (BLA) to the U.S. Food and Drug Administration (FDA) seeking marketing approval for PEG-Intron(TM) (peginterferon alfa-2b) Powder for Injection as once-weekly monotherapy for the treatment of chronic hepatitis C. Some 4 million Americans are chronically infected with the hepatitis C virus, according to the Centers for Disease Control and Prevention (CDC).

Intron A is a recombinant version of naturally occurring alpha interferon, which has been shown to exert both antiviral and immunomodulatory effects. Schering-Plough markets Intron A worldwide for 16 major antiviral and anticancer indications.

Rebetol® (Ribavirin, USP) Capsules is an oral formulation of ribavirin, a synthetic nucleoside analog with broad-spectrum antiviral activity. Schering-Plough has exclusive rights to market oral ribavirin for hepatitis C in all major world markets through a licensing agreement with ICN Pharmaceuticals, Inc. of Costa Mesa, Calif.

Schering-Plough is a research-based company engaged in the discovery, development, manufacturing and marketing of pharmaceutical products worldwide.