Schering-Plough Corporation announced that Schering-Plough K.K., the company's subsidiary in Japan, has submitted a New Drug Application (J-NDA) to the Ministry of Health, Labor and Welfare (MHLW) seeking marketing approval for Peg-Intron (peginterferon alfa-2b) Powder for Injection for use in combination with Rebetol (ribavirin) capsules for the treatment of chronic hepatitis C. The MHLW will provide a priority review of the application. If approved, Peg-Intron and Rebetol will be the first and only pegylated interferon-based combination therapy approved in Japan for treating chronic hepatitis C.

Hepatitis C is estimated to affect some 2 million people in Japan, according to MHLW. It is the leading cause in Japan of chronic liver disease, cirrhosis and hepatocellular carcinoma, and is associated with more than 30,000 deaths there annually. Hepatitis C is the most common reason for liver transplant in major world markets, including Japan, according to a study conducted by the World Health Organization (WHO).

Schering-Plough K.K. currently markets Rebetol in Japan for use in combination with Intron A (interferon alfa-2b, recombinant) Injection for chronic hepatitis C. Intron A also is approved in Japan for use as monotherapy for hepatitis C, hepatitis B and several cancer indications.

Peg-Intron is a longer-acting form of Intron A that uses proprietary PEG technology developed by Enzon, Inc. of Bridgewater, N.J. Peg-Intron, recombinant interferon alfa-2b linked to a 12,000 dalton polyethylene glycol (PEG) molecule, is a once-weekly therapy that is designed to achieve an effective balance between antiviral activity and elimination half-life. Schering-Plough holds an exclusive worldwide license to Peg-Intron.

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 for 16 major antiviral and anticancer indications worldwide.

Rebetol is an oral formulation of ribavirin, a synthetic nucleoside analog. Schering-Plough has worldwide rights to market oral ribavirin for hepatitis C through a licensing agreement with Valeant Pharmaceuticals International, formally ICN Pharmaceuticals, of Costa Mesa, Calif.