Treatment of chronic hepatitis B infection using interferon

Abstract

Four to 6 months of conventional interferon alpha (IFN-alpha) (5MU daily or 10MU three times weekly) resulted in HBeAg loss in approximately 33% of HBeAg positive patients (controls: 12%). Longer treatment duration improved HBeAg seroconversion. Children with chronic HBV infection and high ALT respond to IFN-a at similar rates. Good end-of-treatment (ET) biochemical and virological response were also achieved with IFN-alpha in HBeAg negative, HBV-DNA positive hepatitis patients. Sustained response (SR) however, was disappointing, but improved with longer duration of treatment: (10-15% SR with 4/6 months treatment: 30% SR with 24 months treatment). Weekly pegylated IFN-alpha2a (PegIFN-alpha2a) for 24 weeks gave a significantly higher HBeAg conversion rate (33%) than conventional IFN-alpha2a (25%). Fifty-two weeks of PegIFN-alpha2b gave a sustained HBeAg loss in 35% patients and HBeAg seroconversion in 29% patients. Similar results were obtained with 48 weeks of weekly PegIFN-alpha2a. PegIFN-alpha2a monotherapy was found to be superior to lamivudine monotherapy in affecting a 6-month SR (normal ALTs and HBV DNA < 20,000 copies/mL) in HBeAg negative/anti-HBe positive chronic hepatitis B patients. There is a tendency for IFN-a and lamivudine combination to result in better sustained response than lamivudine monotherapy. This tendency is also observed with PegIFN-a and lamivudine combination although the combination did not appear to be better than PegIFN-alpha monotherapy. IFN induced HBeAg seroconversion is durable, could increase over time and resulted in better overall survival and survival free of hepatic decompensation or hepatocellular cancer. The main advantage of IFN-a therapy is that a course of finite duration may achieve sustained off-therapy response in a proportion of both HBeAg positive and HBeAg negative chronic hepatitis B patients. However, IFN treatment is usually associated with side-effects, especially flu-like symptoms, fatigue, neutropenia, thrombocytopenia and depression. These are usually tolerable but may require dose modification and premature cessation of treatment (5%). Interferon therapy induced hepatitis flares may lead to decompensation in patients with cirrhosis and can be dangerous in patients with decompensated liver function despite dose reduction.