Effect of virological response on post-treatment durability of lamivudine-induced HBeAg seroconversion

Determinants for sustained HBeAg response to lamivudine therapy

There are inconsistent data on the durability of hepatitis B e antigen (HBeAg) seroconversion after lamivudine is discontinued. The aim of this study was to examine the determinants for sustained HBeAg response to lamivudine therapy. Both host and viral factors as well as the drug factor were compared between 43 patients with sustained HBeAg response and 39 patients whose response was not sustained. All of them received a mean period of 16 months (range, 3-55 months) lamivudine therapy and had achieved complete response (HBeAg seroconversion plus HBV DNA seroclearance by hybrid capture assay and normal alanine aminotransferase [ALT]) and were followed-up for a mean period of 44 months (range, 12-88 months). Stepwise logistic regression model was used to estimate the sustained response on the presence of the following variables: age; gender; pretherapy ALT; total bilirubin and HBV DNA levels; time to HBeAg seroconversion; additional lamivudine treatment after HBeAg seroconversion; total duration of treatment; hepatitis activity index scores; periportal, intralobular, and portal inflammation and fibrosis scores; scores excluding fibrosis; status of precore mutation; basal core promoter mutation; and genotype. The results showed that genotype (OR, 5.922; 95% CI, 1.611-21.768; P =.007), age (OR, 0.943; 95% CI, 0.891-0.997; P =.040), and additional treatment (OR, 1.097; 95% CI, 1.028-1.171; P =.005) were independent factors to sustained HBeAg response. Further categorical analysis disclosed that patients with genotype B, age < or =36 years, and additional lamivudine treatment over 8 months have higher sustained response. In conclusion, HBV genotype, age, and additional treatment are the major determinants for the sustained HBeAg response to lamivudine therapy.

Long-term additional lamivudine therapy enhances durability of lamivudine-induced HBeAg loss: a prospective study

BACKGROUNDS/AIMS

In the treatment of chronic hepatitis B (CHB) with lamivudine, adequate duration of the therapy remains to be determined. In this prospective study, the authors intended to investigate whether long-term additional administration of lamivudine might enhance the durability of lamivudine-induced HBeAg seroconversion.

METHODS

Eighty-five CHB patients who achieved HBeAg seroconversion by lamivudine received additional lamivudine therapy for at least 24 months at a dose of 100 mg per day. Among them, 61 patients whose serum HBeAg and HBV-DNA (solution hybridization assay) had been negative persistently for >24 months discontinued lamivudine therapy and followed-up for >12 months. We calculated the cumulative reappearance rate of serum HBV-DNA and HBeAg and also evaluated the predictive factors for post-treatment virologic relapse.

RESULTS

The cumulative reappearance rates of serum HBV-DNA following cessation of lamivudine therapy at 6 months, 1 year and 2 years were 15%, 21%, and 31%, respectively. The cumulative reappearance rates of serum HBeAg at 6 months, 1 year and 2 years were 11%, 13% and 16%, respectively. Old age and presence of precore mutant were two independent predictive factors for viral relapse.

CONCLUSION

These results suggested that long-term additional administration of lamivudine might enhance the durability of lamivudine-induced HBeAg seroconversion.

A quantitative method to detect HBV cccDNA by chimeric primer and real-time polymerase chain reaction

Hepatitis B virus (HBV) covalently closed circular DNA (cccDNA), is a continuous double chain ring, while other DNA forms contain a gap on each chain at the position of direct repeat 1 sequence (DR1) and direct repeat 2 sequence (DR2), respectively. At present it is still difficult to detect with high sensitivity and specificity and quantify the HBV cccDNA pool in the nucleus of the hepatocyte. A chimeric primer was designated in which segment A near 3' end is complementary to HBV plus strand just before the DR2 region gap, and segment B near 5' end is consensus to part of the human immunodefficient virus genomic sequence, without homogenetic relationship to HBV genome. Promoted by taq DNA polymerase, a single nucleotide strand is elongated from chimeric primer generated by HBV cccDNA. In contrast, other HBV DNA forms do not produce a single nucleotide strand due to the cessation of elongation reaction at the DR2 gap. The newly formed single nucleotide strand is subsequently amplified by a new polymerase chain reaction system (PCR), in which a primer, identical to chimeric primer segments B, is used to ensure specific amplification, avoiding other HBV DNA format inference. In addition, a taqman probe was used in the PCR system to report the detection signal, and for constructing a standard curve between cycle threshold (Ct) value and the template quantity. This technique proved to be effective for rapid and sensitive detection and quantitation of HBV cccDNA with high specificity and efficacy.

Durability of serologic response after lamivudine treatment of chronic hepatitis B

Forty subjects with chronic hepatitis B and hepatitis B e antigen (HBeAg) seroconversion following lamivudine therapy in previous trials were monitored after treatment to assess the durability of serologic responses. Patient follow-up began a median of 4.3 months after completion of therapy in previous trials. At months 2, 4, 6, 9, and 12 of year 1, and every 6 months thereafter, we tested for HBeAg and hepatitis B surface antigen (HBsAg), hepatitis B virus (HBV) DNA, and alanine aminotransferase (ALT). After a median (range) of 36.6 (4.8-45.6) months of follow-up monitoring, HBeAg seroconversion was demonstrated at the last visit by 77% (30 of 39) of patients. In a post hoc analysis of a slightly different population of all 65 patients with HBeAg seroconversion in previous trials, the 3-year durability of HBeAg seroconversion measured from the time immediately after discontinuing lamivudine therapy was 64%. Nine (9 of 40, 23%) patients were HBsAg negative at the last assessment. Seventy-four percent (17 of 23) of patients with baseline undetectable HBV DNA and normal ALT maintained these responses at the last visit. Eight patients (8 of 40, 20%) initiated retreatment for reappearance of HBV markers, and 7 showed biochemical and/or virologic improvement (including regained HBeAg seroconversion in 2). No safety issues of concern emerged. In conclusion, most HBeAg responses achieved during lamivudine therapy were durable, and most responders experienced prolonged clinical benefit after HBeAg seroconversion and subsequent discontinuation of lamivudine. Lamivudine retreatment for reappearance of hepatitis B markers can achieve resumption of viral suppression.