Schering-Plough Corporation's country operations in Japan, has received marketing approval for a new, additional indication for Peg-Intron (peginterferon alfa-2b) powder for injection in combination with Rebetol (ribavirin) capsules for the treatment of chronic hepatitis C in adult patients other than those with genotype 1 virus and high viral load. This expanded use represents approximately 40 per cent of the patient population in Japan. With this approval, Peg-Intron and Rebetol is indicated for the treatment of the vast majority of Japanese patients diagnosed with chronic hepatitis C virus (HCV) infection.

The approval by the Ministry of Health, Labour and Welfare (MHLW) follows a priority review designation granted May 18, 2005. An estimated 1 to 2 million Japanese are chronically infected with hepatitis C, claims a company release.

Peg-Intron and Rebetol was first approved in Japan in October 2004 for treating patients with genotype 1 virus (genotype 1a or 1b) and high viral load for a recommended duration of 48 weeks. With this new, expanded approval, the recommended duration of therapy for all other HCV indications is 24 weeks. This includes patients with genotype 2 or 3 virus and high viral load, as well as patients with genotype 1, 2 or 3 virus and low viral load who did not respond or who relapsed following treatment with interferon monotherapy. In the Japanese clinical study supporting this approval, a sustained virologic response (SVR) rate of nearly 90 per cent was achieved in these patients with 24 weeks of therapy.

"This expanded indication for Peg-Intron and Rebetol combination therapy represents a significant advance in the treatment of chronic hepatitis C, a major public health problem in Japan. These approvals, and the supporting clinical data, further underscore the efficacy of individualised, weight-based Peg-Intron used in combination with Rebetol in treating chronic hepatitis C."

Peg-Intron and Rebetol is the only pegylated interferon-based combination therapy for hepatitis C approved in Japan. Peg-Intron is administered once weekly in combination with Rebetol daily. Importantly, Peg-Intron is the only peginterferon product approved in Japan for which a blood test is not required before every injection.

HCV genotype 1 is generally considered to be the most difficult-to-treat form of hepatitis C and is the most common form in Japan, accounting for approximately 70 per cent of all HCV infections there.

Hepatitis C is the leading cause in Japan of liver cancer, with more than 35,000 deaths occurring annually. Hepatitis C is the most common reason for liver transplant in major world markets, including Japan, according to the World Health Organization (WHO).