Schering-Plough Corporation announced that Schering-Plough K.K., the company's subsidiary in Japan, has received 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.

Peg-Intron and Rebetol combination therapy is the first and only pegylated interferon-based combination therapy approved in Japan. An estimated 1 to 2 million Japanese are reported chronically infected with hepatitis C. The approval by the Ministry of Health, Labour and Welfare (MHLW) follows a priority review. Peg-Intron will become available in Japan upon National Health Insurance Reimbursement price listing.

"The introduction of Peg-Intron and Rebetol combination therapy represents a significant development in the treatment of hard-to-treat chronic hepatitis C, a major public health problem in Japan," said Robert J. Spiegel, chief medical officer and senior vice president of medical affairs, Schering-Plough Research Institute. "This approval, and the supporting clinical data, further underscore the value of individualized, weight-based Peg-Intron used in combination with Rebetol in treating chronic hepatitis C," he added.

Peg-Intron, which is administered once weekly in combination with Rebetol daily for 48 weeks, is indicated in patients chronically infected with hepatitis C virus (HCV) genotype 1 (genotype 1a or 1b) and high viral load. HCV genotype 1 is considered the most difficult-to-treat form of hepatitis C and is the most common form in Japan, accounting for approximately 60 per cent of all HCV infections there.

Importantly, Peg-Intron is the only peginterferon product approved in Japan for which a blood test is not required before every injection.

In the Japanese clinical study supporting the approval, 48 weeks of Peg-Intron and Rebetol combination therapy achieved a sustained virologic response (SVR)(1) rate of 48 per cent in patients with HCV genotype 1 and high viral loads. An SVR rate of 63 per cent was achieved with Peg-Intron and Rebetol in the portion of these patients who had relapsed following previous interferon treatment.

Peg-Intron, recombinant interferon alfa-2b linked to a 12,000 dalton polyethylene glycol (PEG) molecule, is a once-weekly therapy dosed according to patient body weight that is designed to achieve an effective balance between antiviral activity and elimination half-life. Peg-Intron is a longer-acting form of Intron A (interferon alfa-2b, recombinant) Injection.

Rebetol is an oral formulation of ribavirin, a synthetic nucleoside analog with broad-spectrum antiviral activity. Schering-Plough K.K. currently markets Rebetol in Japan for use in combination with Intron A for chronic hepatitis C.