INTRON A has been approved for extension of therapy for chronic viral hepatitis C for 18-24 months. INTRON A therapy for 18-24 months has been shown to nearly double patients’ sustained response rates, compared to six months of treatment (the previously indicated treatment regimen), according to studies submitted to the FDA.
INTRON A is a recombinant version of a naturally occurring alpha interferon, with both antiviral and immunomodulatory effects. In the United States it has been cleared for use by the FDA for chronic viral hepatitis B, chronic viral hepatitis C, malignant melanoma, hairy cell leukemia, AIDS-related Kaposi’s sarcoma and condylomata acuminata (venereal warts). INTRON A is marketed in 68 countries worldwide for 16 major indications.
Two independent clinical studies were used to support the submission for 18-24 months therapy duration: In study No. 1, patients received 3 million international units (MIU), three times a week (TIW) of INTRON A for a period of 18 months. In study No. 2, patients received 3 MIU, TIW for a period of 24 months. In both studies, the extended duration arms were compared to the previously indicted six month course of therapy.
The combined results from the multicenter trials demonstrated that 24 percent of all patients treated for 18-24 months achieved a durable sustained response (6 months post-therapy) compared with 12.5 percent for those treated for six months.
Similarly, improvement in liver cell inflammation and death (necroinflammatory activity) -- another measure of response to treatment -- was seen in significantly more patients who received INTRON A for 18-24 months compared to those who received six months of therapy (58 percent versus 38 percent respectively).
Some 4 million to 4.5 million Americans are chronically infected with the hepatitis C virus, according to the Centers for Disease Control and Prevention (CDCP). Because the disease is often asymptomatic in its early stages, the vast majority of infected individuals are unaware of their disease until they develop serious liver complications. The CDCP has estimated that 20-50 percent of chronically infected hepatitis C patients will develop liver cirrhosis, and 20-30 percent of those will go on to develop liver cancer or liver failure requiring liver transplant. Hepatitis C infection contributes to the death of more than 12,000 Americans each year, and this toll is expected to triple by the year 2010, according to the CDCP. American Liver Foundation researchers state that liver failure due to hepatitis C infection is the leading cause of liver transplants in the United States.