Antiviral kinetics of tenofovir alafenamide and tenofovir disoproxil fumarate over 24 weeks in women of childbearing potential with chronic HBV

Enhancing interventions for prevention of mother-to-child- transmission of hepatitis B virus

Prevention of mother-to-child transmission of hepatitis B virus (HBV) infection is a cornerstone of efforts to support progress towards elimination of viral hepatitis. Current guidelines recommend maternal screening, antiviral therapy during the third trimester of high-risk pregnancies, universal and timely HBV birth dose vaccination, and post-exposure prophylaxis with hepatitis B immunoglobulin for selected neonates. However, serological and molecular diagnostic testing, treatment and HBV vaccination are not consistently deployed, particularly in many high endemicity settings, and models predict that global targets for reduction in paediatric incidence will not be met by 2030. In this article, we briefly summarise the evidence for current practice and use this as a basis to discuss areas in which prevention of mother-to-child transmission can potentially be enhanced. By reducing health inequities, enhancing pragmatic use of resources, filling data gaps, developing advocacy and education, and seeking consistent investment from multilateral agencies, significant advances can be made to further reduce vertical transmission events, with wide health, societal and economic benefits.

Effectiveness and safety of tenofovir amibufenamide and its comparison with tenofovir alafenamide in patients with chronic hepatitis B: results from a retrospective real-world study

Background/aim: Tenofovir amibufenamide (TMF) has shown potent antiviral efficacy in randomized clinical studies. This study aimed to reveal the effectiveness and safety of tenofovir amibufenamide in the real world and compared tenofovir amibufenamide to tenofovir alafenamide (TAF) in patients with chronic hepatitis B (CHB). Methods: In this retrospective study, tenofovir amibufenamide-treated chronic hepatitis B patients were divided into treatment-naive (TN) and treatment-experienced (TE) groups. Furthermore, tenofovir alafenamide-treated patients were enrolled using the propensity score matching method (PSM). We assessed the virological response (VR, HBV DNA < 100 IU/mL) rate, renal function, and blood lipid changes during 24 weeks of treatment. Results: Virologic response rates at week 24 were 93% (50/54) in the treatment-naive group and 95% (61/64) in the treatment-experienced group. The ratios of alanine transaminase (ALT) normalization were 89% (25/28) in the treatment-naive group and 71% (10/14) in the treatment-experienced group (p = 0.306). Additionally, serum creatinine decreased in both the treatment-naive and treatment-experienced groups, (-4.44 ± 13.55 μmol/L vs. -4.14 ± 9.33 μmol/L, p = 0.886), estimated glomerular filtration rate (eGFR) increased (7.01 ± 12.49 ml/min/1.73 m² vs. 5.50 ± 8.16 ml/min/1.73 m², p = 0.430), and low-density lipoprotein cholesterol (LDL-C) levels increased (0.09 ± 0.71 mmol/L vs. 0.27 ± 0.68 mmol/L, p = 0.152), whereas total cholesterol/high-density lipoprotein cholesterol (TC/HDL-C) levels decreased continuously from 3.26 ± 1.05 to 2.49 ± 0.72 in the treatment-naive group and from 3.31 ± 0.99 to 2.88 ± 0.77 in the treatment-experienced group. Using propensity score matching, we further compared virologic response rates between the tenofovir amibufenamide and tenofovir alafenamide cohorts. Virologic response rates in treatment-naive patients were higher in the tenofovir amibufenamide cohort [92% (35/38) vs. 74% (28/38), p = 0.033]. Virologic response rates in treatment-experienced patients showed no statistical difference between the tenofovir amibufenamide and tenofovir alafenamide cohorts. Conclusion: Tenofovir amibufenamide had profound antiviral effectiveness and no adverse effects on renal function or blood lipids. Additionally, tenofovir amibufenamide was more efficient than tenofovir alafenamide in inhibiting viral replication, which needs to be demonstrated in future studies.

The Use of Tenofovir Disoproxil Fumarate and Tenofovir Alafenamide for Preventing Vertical Transmission of Hepatitis B

BACKGROUND

Mother-to-child transmission (MTCT) of hepatitis B virus may occur in highly viremic mothers despite the infants receiving appropriate immunoprophylaxis. We aimed to review tenofovir disoproxil fumarate (TDF) and tenofovir alafenamide (TAF) data for preventing MTCT.

METHODS AND DATA SELECTION

We performed a systematic review between January 1, 2015 and December 31, 2021 on PUBMED, EMBASE, Cochrane, CNKI, and Wanfang databases. Data was extracted from randomized controlled trials or cohort studies in English or Chinese. The outcomes of interest included the efficacy and safety of TDF versus TAF or TDF/TAF versus placebo for preventing MTCT (PROSPERO registration: CRD42021256656).

RESULTS

Data from forty-three studies (13 randomized controlled trials, 30 nonrandomized studies) were included in the review. All infants in the studies received appropriate immunoprophylaxis. Among 3656 highly viremic mothers treated with TDF, hepatitis B virus DNA suppression to the levels <200,000 IU/mL at delivery was achieved in 34% to 100% of mothers. MTCT rates were 0 to 5% and 2 to 83% in mothers treated with TDF and in those who received no treatment, respectively. Congenital malformation rates were 0 to 2.1% in the TDF groups, which did not differ from the nontreated groups. Similar findings were reported in 4 studies that enrolled 326 mothers for maternal TAF therapy, resulting in 0% of MTCT and 0% infant malformation. All studies observed that TDF or TAF maternal therapy reduced MTCT rates significantly without safety concerns when compared with untreated groups, except for 1 RCT that failed the therapeutic endpoint.

CONCLUSIONS

TDF is well established for preventing MTCT in highly viremic mothers, whereas TAF may become an option as data emerges.

The role of tenofovir disoproxil fumarate for preventing vertical transmission of hepatitis B

Background

Since immunoprophylaxis failure can occur if maternal serum hepatitis B virus (HBV) DNA levels are >200,000 IU/ml, tenofovir disoproxil fumarate (TDF) therapy has been investigated for preventing mother to child transmission (PMTCT).

Methods

A literature search for maternal TDF therapy for PMTCT between 1/1/2015 and 7/1/21 on PUBMED, EMBASE, Cochrane, CNKI, and Wanfang databases was performed. Data from RCTs in English or Chinese were extracted and reviewed. The outcomes of interest included the efficacy and safety of TDF versus placebo for PMTCT.

Results

Among 11 RCTs identified from the databases, the risk-of-bias was low. All studies demonstrated that maternal TDF therapy initiated from the second or third trimester for highly viremic chronic hepatitis B mothers is highly effective and safe in the PMTCT of HBV, except one RCT performed in Thailand which showed no therapeutic advantage on TDF treatment versus placebo for PMTCT (0% vs 3% transmission). Recent emerging data suggest that maternal TDF therapy initiated at the 2nd or early 3rd trimester in mothers with HBV DNA >200,000 IU/ml achieved viremic control before delivery. In the 4-year long follow-up study for maternal TDF therapy, there were no impacts on infants’ physical growth, psychological or mental development, and bone mineral density after fetal exposure to TDF. In the light of updated efficacy and safety data from RCTs, an algorithm was proposed. The approaches in resource-limit areas were discussed.

Conclusions

TDF is safe for both mothers and infants as the preferred therapy for PMTCT in highly viremic mothers. TDF should be initiated at the second or early third trimester in the combination of the appropriate infants’ immunoprophylaxis.