Results of a Phase II study of PEGASYS showed that the drug has the potential as an important new treatment for chronic hepatitis B (CHB). PEGASYS is already been approved for the treatment of chronic hepatitis C (CHC) and has been shown to provide superior efficacy when compared to conventional interferon therapy.
According to Prof. Ming Yang Lai, one of the study authors from National Taiwan University College of Medicine, Taiwan, all the study results they have heard suggest that PEGASYS could be a major advance in the treatment of hepatitis B. "Each of the currently available treatments has considerable limitations. In contrast, PEGASYS appears to be a treatment that offers significantly improved efficacy, even in patients with treatment resistant disease," he stated.
PEGASYS, a new generation hepatitis therapy that is different by design, has demonstrated superior efficacy to conventional interferon combination therapy in patients infected with HCV of all genotypes. The benefits of PEGASYS are derived from its new generation large 40 kilodalton branched-chain polyethylene glycol (PEG) construction, which delivers sustained therapeutic concentrations over an entire seven-day dosing interval. This results in true seven-day sustained viral suppression. In addition, PEGASYS is preferentially distributed to the liver, the primary site of infection. PEGASYS is administered once weekly in an easy-to-use pre-filled syringe with a fixed 180 mcg starting dose for all patient types.
Roche, the company which has introduced PEGASYS, has been active in the viral hepatitis disease area having introduced Roferon-A for hepatitis B and C.. PEGASYS is in phase III clinical development for patients infected with the HBV virus. Roche also manufactures HBV and HCV diagnostic and monitoring systems. The COBAS AMPLICOR Test, and the AMPLICOR MONITOR Test, two testing systems used to detect the presence of, and quantity of, HBV DNA or HCV RNA in a person''s blood. Roche''s commitment to hepatitis has been further reinforced by the in-licensing of Levovirin, an alternative antiviral. Levovirin will be studied with the objective of demonstrating superior tolerability over the current standard, ribavirin.
In a study involving 194 patients, researchers found more than twice as many PEGASYS patients responded to treatment than those using conventional interferon. Twenty right per cent of patients treated with PEGASYS 180 (micro) g once weekly for 24 weeks achieved the combined response of HBeAg clearance (indicating viral replication has stopped), HBV DNA suppression (indicating the virus is effectively controlled) and ALT normalization (indicating normal function of the liver). In contrast, only 12 per cent of interferon alfa-2a patients achieved these results. Similarly, HBeAg seroconversion (loss of HBeAg and presence of anti-HBe) was achieved in 33 per cent of patients treated weekly with PEGASYS compared to 25 per cent of patients treated with conventional interferon alfa-2a. The absence of HBeAg viral protein and the presence of HBV-neutralising antibody anti-HBe indicates that the immune system has regained control over HBV.
In the same study, PEGASYS demonstrated that it is also effective in patients with difficult to treat hepatitis B - that is, those with low pre-treatment ALT levels and high pre-treatment viral load. In a study presented by Prof. Graham Cooksley, Director of Clinical Research Centre, Royal Brisbane Hospital Research Foundation, Australia, 44 per cent of patients with difficult-to-treat HBV treated with PEGASYS achieved HBeAg loss compared to 17 per cent on conventional Interferon alfa-2a.
"As physicians, we are very encouraged by these early results with PEGASYS. It is especially important to find a treatment for patients with hard-to-treat disease, because they typically respond poorly to current therapies," said Prof. Cooksley.
PEGASYS has been approved for the treatment of chronic hepatitis C in 48 countries, including the European Union. PEGASYS has also been submitted for review by regulatory authorities in the United States and Roche expects approval in monotherapy and combination later this year.
Lamivudine and conventional interferon alfa, the currently available standard therapies for hepatitis B in Asia, have clear limitations in terms of overall efficacy. Moreover, about 20 per cent of patients treated with lamivudine develop resistance to the drug within one year of therapy. In addition, a number of patients treated with lamivudine are required to continue therapy indefinitely. PEGASYS overcomes these limitations by delivering higher efficacy within a defined treatment duration. In addition, hepatitis B virus does not develop resistance to PEGASYS.
Phase II, randomized clinical trials with PEGASYS are currently underway in both HBeAg positive and HBeAg negative patients.
Hepatitis B is a blood-born virus that attacks the liver and is the most common serious liver infection in the world. The Hepatitis B virus is highly contagious and is relatively easy to transmit from one infected individual to another. It is 100 more times infectious than the HIV virus. More than two billion people have been infected by HBV and 350 million people have chronic infection, which can be easily transmitted by blood-to-blood contact, during birth, unprotected sex, and by sharing needles. For those chronically infected with HBV, treatment is the only option. Hepatitis B is the 9th leading cause of death in the world; left unchecked, it can cause liver cancer and death.