Background & Aims: Hepatitis B virus (HBV) covalently closed circular DNA (cccDNA) is a

The template of hepatitis B virus (HBV) transcription, the covalently closed circular DNA (cccDNA), plays a key role in the life cycle of the virus and permits the persistence of infection. Novel molecular techniques have opened new possibilities to investigate the organization and the activity of the cccDNA minichromosome in vivo, and recent advances have started to shed light on the complexity of the mechanisms controlling cccDNA function. Nuclear cccDNA accumulates in hepatocyte nuclei as a stable minichromosome organized by histone and non-histone viral and cellular proteins. Identification of the molecular mechanisms regulating cccDNA stability and its transcriptional activity at the RNA, DNA and epigenetic levels in the course of chronic hepatitis B (CH-B) infection may reveal new potential therapeutic targets for anti-HBV drugs and hence assist in the design of strategies aimed at silencing and eventually depleting the cccDNA reservoir.

The possibility of safe discontinuation of therapy with nucleos(t)ide analogues (NAs) remains one of the most controversial topics in the management of chronic hepatitis B. Therefore, we systematically reviewed the existing data on NA discontinuation in this setting and tried to identify factors affecting the probability of posttherapy remission. A literature search was performed in order to identify all published studies including patients who discontinued NAs in virological remission (VR) and were followed for 12 months thereafter. Twenty-five studies with 1716 patients were included. The pooled rates of durable VR remission were 51.4%, 39.3%, and 38.2% at 12, 24, and 36 months, respectively, after NA discontinuation, being relatively higher in initially hepatitis B e antigen (HBeAg)-positive patients (62.5%, 53.4%, 51.5%) than HBeAg-negative patients (43.7%, 31.3%, 30.1%) (P 5 0.064). The weighted probability of durable biochemical remission was 65.4%, being numerically higher in HBeAg-positive than HBeAg-negative patients (76.2% versus 56.7%, P 5 0.130). The weighted probability of hepatitis B surface antigen loss was 2.0%. The rates of durable VR did not significantly differ according to the VR definition (hepatitis B virus DNA <200, < 2000, < 20,000 IU/mL) or duration of on-therapy VR in HBeAg-positive patients, but they were significantly higher in studies with HBeAg-negative patients and on-therapy VR > 24 than £ 24 months (VR at 12 months off-NAs: 75.0% versus 35.6%, P 5 0.005). The weighted probability of durable HBeAg seroconversion was 91.9% and 88.0% at 12 and 24 months, respectively, after NA discontinuation without being affected by the duration of on-therapy VR or consolidation therapy (>6 months in all studies). Conclusion: Durable VR seems to be feasible in a substantial proportion of patients who discontinue long-term NA therapy; on-therapy VR > 24 months offers higher chances of off-NA VR in patients with HBeAg-negative chronic hepatitis B. (HEPATOLOGY 2016;63:1481-1492 T reatment against hepatitis B virus (HBV) has dramatically improved over the last 15 years, but HBV eradication remains a rarely attainable target. (1-3) Pegylated interferon-alfa therapy given for a finite duration of usually 48 weeks can achieve sustained off-therapy responses, with almost half of the responders clearing hepatitis B surface antigen (HBsAg) in the long term. However, only 20%-30% of patients with hepatitis B e antigen (HBeAg)-positive or HBeAg-negative chronic hepatitis B (CHB) may achieve sustained off-therapy responses after a course of pegylated interferon-alfa. (1)(2)(3) Many patients are reluctant to start treatment with this agent because interferon-alfa may have severe side effects as well as an unfavorable safety profile. Thus, oral antiviral agents, nucleos(t)ide analogues (NAs), represent the main therapeutic option for the majority of CHB patients. (4) Abbreviations: ALT, alanine aminotransferase; BR, biochemical remission; CHB, chronic hepatitis B; CI, confidence interval; HBeAg, hepatitis B e a...