Editorial: Anti-viral therapy for prevention of perinatal HBV transmission--extending therapy beyond birth and the risk of post-partum flare

Tenofovir disoproxil fumarate therapy to prevent hepatitis B virus vertical transmission-A review of maternal and infant outcomes

Hepatitis B virus (HBV) is a global health problem. Vertical transmission of HBV from HBV surface antigen (HBsAg)-positive mothers to their infants is the most common cause of HBV infection worldwide. The use of passive-active immunoprophylaxis is >90% effective in reducing the risk of vertical transmission, but immunoprophylaxis failure can occur in infants born to mothers with high viraemia. Thus, it is recommended that pregnant women with HBV-DNA level >200 000 IU/ml receive nucleos(t)ide analogue (NA) treatment [i.e. tenofovir disoproxil fumarate (TDF), lamivudine or telbivudine] during third trimester to prevent infant immunoprophylaxis failure. TDF is recommended as the first-line therapy based on available data on efficacy, safety and resistance profile. However, maternal immunological reconstitution following parturition can increase immune-mediated flares to viral antigens that is potentially exacerbated following TDF withdrawal. In this article, we review available data on the efficacy and safety of TDF administration to prevent HBV mother-to-child transmission. We also discuss changes in maternal viral markers [i.e. HBV-DNA, HBV e antigen and HBsAg] and alanine aminotransferase during follow-up post-partum in mothers received NA to prevent HBV vertical transmission.

Serum Aminotransferase Flares in Pregnant and Postpartum Women With Current or Prior Treatment for Chronic Hepatitis B

BACKGROUND AND AIMS

Antiviral therapy is recommended for pregnant women with chronic hepatitis B (CHB) and hepatitis B virus (HBV) DNA>200,000 IU/mL, but there is less consensus on management of women who discontinue therapy in anticipation of pregnancy or who become pregnant while on therapy. The goal of this study was to describe flares in alanine aminotransferase (ALT) during pregnancy and postpartum in CHB women with current and/or prior treatment.

METHODS

This was a multicenter, retrospective study of 67 pregnancies in 56 CHB women treated before and/or during pregnancy. Main outcomes were frequency, severity, and resolution of ALT flare (≥5× upper limit of normal or ≥3× baseline, whichever was higher).

RESULTS

During pregnancy, ALT flares (95 to 1064 U/L) were observed in 16% (7/43) of women who stopped treatment before pregnancy and 31% (4/13) of women who discontinued treatment during first trimester, many of whom had high HBV DNA levels (4.9 to 8.0 log IU/mL). No flares (0/11) were observed in women who continued treatment. Postpartum ALT flares (104 to 1584 U/L) were observed in 0% (0/15) of women who were completely untreated during pregnancy, 29% (2/7) of women who discontinued treatment in first trimester, 33% (3/9) of women who stopped treatment at delivery, and 22% (4/18) of women who continued treatment postpartum.

CONCLUSIONS

In previously treated women with CHB, ALT flares were common during pregnancy and postpartum, especially if antiviral therapy was discontinued shortly before pregnancy, during first trimester, or at delivery. Thus, these pregnant women should be monitored closely throughout pregnancy and the early postpartum period; larger studies are needed to further characterize the natural history of HBV infection during pregnancy and postpartum.

Nucleoside/nucleotide analogues in the treatment of chronic hepatitis B infection during pregnancy: a systematic review

BACKGROUND

Women of childbearing age who have developed chronic hepatitis B (CHB) infection, especially HBeAg-positive highly viraemic pregnant women, are largely responsible for the familial transmission of the infection. Therefore, choosing the most effective and safest antiviral medications to manage pregnant CHB patients is of crucial importance.

MATERIALS AND METHODS

The PubMed and Scopus databases were searched through September 2017, for all the journal articles possessing original results regarding treatment of CHB pregnant women with any nucleos(t)ide analogue (NA) therapies, including lamivudine (LAM), adefovir (ADV), entecavir (ETV), telbivudine (LdT), and tenofovir (TDF).

RESULTS

After the primary search, 882 studies were recognized, and updating the searching results, 41 journal articles with original data were investigated, involving 3874 newborn infants from mothers with CHB, and their mothers completed follow-up until the delivery. The most important basic data and results regarding the efficacy of drugs, the rate of vertical transmission, safety issues associated with pairs of mothers and infants, median levels of HBV DNA, breastfeeding data, and rate of rate of vaccination success were collected. Moreover, possible key conclusion, recommendations, and learned lessons were discussed. Among the evaluated NAs, all LAM was efficient and safe. LdT was found to be very effective but had some safety concerns. In contrast, TDF had the advantages of both effectiveness and safety.

CONCLUSION

According to data in the literature, initiation of TDF at the trimester of pregnancy in combination with immunoprophylaxis to prevent mother-to-child transmission (MTCT) of CHB infection is strongly recommended as well as successful immunization of CHB pregnant women by anti-HBV vaccines.

Serum Alanine Aminotransferase and Hepatitis B DNA Flares in Pregnant and Postpartum Women with Chronic Hepatitis B

OBJECTIVES

Alterations in the immune system during pregnancy have been associated with reactivation of hepatitis B virus (HBV) in chronic hepatitis B (CHB) women. However, the effects of pregnancy on CHB remain not well understood. The goal of this study was to examine flares in HBV DNA and serum alanine aminotransferase (ALT) during pregnancy and postpartum in CHB women untreated prior to pregnancy.

METHODS

This was a multicenter retrospective study of 113 pregnancies in 101 CHB women who presented during pregnancy at two community gastroenterology clinics and two tertiary medical centers in the United States during 1997-2015. Outcomes analyzed included onset, severity, and resolution of flares in HBV and ALT that occurred prior to starting antiviral therapy, if antiviral therapy was subsequently initiated. Women who initiated antiviral therapy during pregnancy were not included in the analysis of postpartum flares.

RESULTS

HBV DNA flares were observed in 9% (8/90) of women during pregnancy and 4% (2/48) of women during postpartum. Flares in ALT (99-2522 U/l) were observed in 6% (7/112) of women during pregnancy and 10% (5/51) of women within the first 3 months of delivery. Age, HBeAg positivity, baseline HBV DNA, baseline ALT, gravida, and parity were not found to be significant predictors of flare.

CONCLUSIONS

Flares in HBV DNA and ALT can occur during late pregnancy and early postpartum in CHB women, and can be severe. Women with CHB should therefore be closely monitored during pregnancy and early postpartum.

Clinical course of 161 untreated and tenofovir-treated chronic hepatitis B pregnant patients in a low hepatitis B virus endemic region

Hepatitis B immunoprophylaxis failure is linked to high maternal viraemia. There is limited North American data on hepatitis B outcomes in pregnancy. Pregnant hepatitis B carriers were enrolled January 2011-December 2014 and offered tenofovir in the 3rd trimester if hepatitis B virus (HBV)-DNA was >7-log IU/mL. Outcomes were determined in treated vs untreated patients. In total, 161 women with 169 pregnancies (one twin, 170 infants; median age 32 years), 18% (29/161) HBeAg+ and median HBV-DNA 2.51 log IU/mL (IQR 1.66-3.65; range 0.8-8.1) were studied. 14.3% (23/161) received tenofovir due to high viral load (16/23, median 74 days, IQR 59-110) or due to liver disease (7/23). In 10/16 treated due to high viraemia, with confirmed adherence, follow-up HBV-DNA showed a 5.49 log decline (P = 0.003). In treatment naïve mothers, median alanine aminotransferase (ALT) increased from 17 IU/L (IQR 12-24) to 29 (IQR 18-36) post-partum (P = 1.5e-7). In seven highly viraemic mothers who declined therapy (HBV-DNA >8-log IU/mL); median ALT increased ~3X from baseline (P < 0.01). 26% (44/169) had Caesarean section with no difference in treated vs untreated subjects. No tenofovir-treated mothers had renal dysfunction. Data were available on 167/170 infants; in 50.8% (85/167) who completed immunoprophylaxis, 98.8% (84/85, including 12 exposed to tenofovir in utero) were HBV immune. One infant born to an HBeAg+ mother with HBV-DNA >8-log IU/mL failed immunoprophylaxis. In this prospective Canadian cohort study, most untreated mothers experienced mild HBV flares. Tenofovir in pregnancy is well tolerated and reduces viral load prior to parturition.

Switching to low tar cigarettes: are the tar league tables relevant?

Background

Chronic hepatitis B (CHB) is a dynamic disease that may be affected by immune changes in pregnancy. Guidelines suggest consideration of nucleos/tide analogs (NA), i.e., tenofovir, (TDF) in highly viremic mothers to reduce vertical transmission risk. HBV variability affects CHB outcome, but little is known about HBV genetic changes in pregnancy due to immune or NA selection.

Objectives

To evaluate HBV diversity in NA treated or untreated pregnant vs. post-partum CHB carriers.

Study Design

In plasma collected from 21 mothers (7 matching pre/post-partum), HBV serological tests, genotype and viral load were assayed. The HBV pre-surface (S) /S overlapping polymerase (P) (N = 20), pre-core (C) /C (N = 11) and/or full genome PCR amplicons (N = 3) underwent clonal sequence analysis.

Results

The median age was 31 y, 71% Asian, 68% genotype B or C, 33% HBV eAg+, 5 received TDF (median HBV DNA 8.5 log IU/ml). In untreated mothers, median antepartum vs. post-partum ALT was 21 vs. 24 U/L and HBV DNA was 2.7 vs. 2.4 log(10) IU/ml. ALT and/or HBV DNA flares occurred during pregnant and/or post-partum period in 47% (10/21). Clonal sequencing antepartum showed the presence of minor “a determinant” and/or vaccine escape mutants (VEM) but drug resistant variants were infrequent. Analysis of pregnant vs. post-partum samples showed different HBV variants and viral diversity.

Conclusions

Differences in immune and/or by NA selective pressures during pregnancy may affect HBV evolution during pregnancy. The presence of minor VEM warrant infant follow-up.