Pegylated interferon alfa for chronic hepatitis B: systematic review and meta-analysis.

Conventional interferon alfa and nucleos(t)ide analogues, such as lamivudine, are frequently used for chronic hepatitis B (CHB) treatment, but are associated with adverse effects and viral resistance. Here we performed a systematic review and meta-analysis evaluating all studies of pegylated interferon alfa (PEG-IFNα) treatment in hepatitis B e antigen (HBeAg)-positive and HBeAg-negative patients with CHB. We searched electronic databases--PubMed, EMBASE, Cochrane Library and LILACS--for randomized controlled trials evaluating PEG-IFNα therapy between 1999 and September 2014. Virological response was the primary outcome. We identified 14 studies involving 2829 patients. Our analysis revealed that PEG-IFNα + lamivudine combination therapy produced better virological and biochemical responses than PEG-IFNα monotherapy in HBeAg-positive and HBeAg-negative patients at the end of treatment. PEG-IFNα + adefovir dipivoxil achieved better seroconversion rate than PEG-IFNα in HBeAg-positive patients at the end of treatment. The present findings demonstrated a beneficial response rate following PEG-IFNα combination therapy with nucelos(t)ides among HBeAg-positive and HBeAg-negative patients with CHB. Further trials are needed to investigate simultaneous and sequential therapy strategies.

The polymerase L528M mutation cooperates with nucleotide binding-site mutations, increasing hepatitis B virus replication and drug resistance.

After receiving lamivudine for 3 years to treat chronic hepatitis B, 67-75% of patients develop B-domain L528M, C-domain M552I, or M552V mutations in the HBV polymerase that render hepatitis B virus (HBV) drug-resistant. The aim of this study was to evaluate the influence of these mutations on viral replication and resistance to antiviral agents. We investigated the replication fitness and susceptibility of the wild-type and five mutant HBVs (L528M, M552I, M552V, L528M/M552I, and L528M/M552V) to 11 compounds [lamivudine, adefovir, entecavir (BMS-200475) (+)-BCH-189 (+/-)-FTC (racivir) (-)-FTC (emtricitabine) (+)-FTC, L-D4FC, L-FMAU (clevudine), D-DAPD, and (-)-carbovir] by transfecting HBV DNA into hepatoma cells and monitoring viral products by Southern blotting. The replication competency of the single C-domain mutants M552I and M552V was markedly decreased compared with that of wild-type HBV. However, addition of the B-domain mutation L528M restored replication competence. Only adefovir and entecavir were effective against all five HBV mutants, and higher doses of these compounds were necessary to inhibit the double mutants compared with the single mutants. The B-domain mutation (L528M) of HBV polymerase not only restores the replication competence of C-domain mutants, but also increases resistance to nucleoside analogues.

Clearance of hepatitis C viral RNA in cirrhotic patients with antiviral therapy.

Interferon is indicated in chronic infection by hepatitis C virus (HCV), however, cirrhosis has been reported as a bad response factor to the therapy. Fifteen cirrhotic patients with HCV, undergoing treatment with recombinant interferon-alpha, ribavirin and/or ursodeoxycholic acid were studied. They were followed-up and evaluated with dosages of alanine aminotransferase and HCV RNA investigation by PCR technique. Of the 15 cirrhotic patients, seven were negative for HCV RNA after antiviral treatment, however ALT was normal in only three of them. Of the eight patients who were not negative, two had normal ALT. Biochemical-virological discrepancy in the follow-up of the patients after antiviral treatment observed in this study has also been reported by other authors. These reports show that the criteria for response to the treatment is to be established.

Interferon in viral liver diseases: pharmacological aspects.

In 1957, two English investigators, Alick Isaacs and Jean Lindenmann made a very important discovery. They observed that when a virus species colonized cells in animals, this invasion interfered with the ability of other viruses, without any association with the former, to produce simultaneous infection. Both investigators observed that the substance responsible for the inhibition was secreted by the infected cells and called it interferon. They also observed that this protein did not directly interact with the virus, but induced the infected cells and surrounding cells to produce other proteins, which were in turn able to block the multiplication of the invading virus.

Long term follow-up and patterns of response of ALT in patients with chronic hepatitis NANB/C treated with recombinant interferon-alpha.

The response to interferon treatment in chronic hepatitis NANB/C has usually been classified as complete, partial or absent, according to the behavior of serum alanine aminotransferase (ALT). However, a more detailed observation of the enzymatic activity has shown that the patterns may be more complex. The aim of this study was to describe the long term follow-up and patterns of ALT response in patients with chronic hepatitis NANB/C treated with recombinant interferon-alpha. A follow-up of 6 months or more after interferon-alpha was achieved in 44 patients. We have classified the serum ALT responses into six patterns and the observed frequencies were as follows: I. Long term response = 9 (20.5%); II. Normalization followed by persistent relapse after IFN = 7 (15.9%); III. Normalization with transient relapse = 5 (11.9%); IV. Temporary normalization and relapse during IFN = 4 (9.1%); V. Partial response (more than 50% of ALT decrease) = 7 (15.9%); VI. No response = 12 (27.3%). In conclusion, ALT patterns vary widely during and after IFN treatment and can be classified in at least 6 types.