Few data are available regarding the use of tenofovir disoproxil fumarate (TDF) during pregnancy for the prevention of mother-to-child transmission of hepatitis B virus (HBV).

Little observational data exist describing telbivudine (LdT) or lamivudine (LAM) use in late pregnancy for preventing hepatitis B mother-to-child transmission (MTCT) in real-world settings. During the period of January 2009 to March 2011, we enrolled hepatitis B e antigen–positive mothers with HBV DNA >6 log₁₀ copies/mL in China. At gestation week 28, the mothers received LdT or LAM until postpartum week 4 or no treatment (NTx). The study endpoints were the safety of LdT/LAM use and MTCT rates. Of the 700 mothers enrolled, 648 (LdT/LAM/NTx = 252/51/345) completed the 52-week study with 661 infants (LdT/LAM/NTx = 257/52/352). On treatment, viral rebound occurred in 1.6% of mothers, all resulting from medication noncompliance. There was no genotypic mutation detected. At delivery, significantly lower HBV DNA levels were noted in mothers who received LdT or LAM versus NTx. Alanine aminotransferase flares were observed in 17.1% of treated mothers versus 6.3% of untreated mothers (P < 0.001). At birth, hepatitis B surface antigen (HBsAg) was detected in 20% and 24% of newborns in the treated and NTx groups, respectively. At week 52, an intention-to-treat analysis indicated 2.2% (95% confidence [CI]: 0.6-3.8) of HBsAg⁺ infants from the treated group versus 7.6% (95% CI: 4.9-10.3) in the NTx group (P = 0.001) and no difference of HBsAg⁺ rate between infants in the LdT and LAM groups (1.9% vs. 3.7%; P = 0.758). On-treatment analysis indicated 0% of HBsAg⁺ infants in the treated group versus 2.84% in the NTx group (P = 0.002). There were no differences for gestational age or infants' height, weight, Apgar scores, or birth defect rates between infants from the treated and untreated groups. Conclusions: LdT and LAM use in late pregnancy for highly viremic mothers was equally effective in reducing MTCT. The treatment was well tolerated with no safety concerns identified. (Hepatology 2014;60:468–476)

INTRODUCTION: The results from 2 phase 3 studies, through 2 years, in chronic hepatitis B infection showed tenofovir alafenamide (TAF) had similar efficacy to tenofovir disoproxil fumarate (TDF) with superior renal and bone safety. We report updated results through 5 years. METHODS: Patients with HBeAg-negative or HBeAg-positive chronic hepatitis B infection with or without compensated cirrhosis were randomized (2:1) to TAF 25 mg or TDF 300 mg once daily in double-blind (DB) fashion for up to 3 years, followed by open-label (OL) TAF up to 8 years. Efficacy (antiviral, biochemical, and serologic), resistance (deep sequencing of polymerase/reverse transcriptase and phenotyping), and safety, including renal and bone parameters, were evaluated by pooled analyses. RESULTS: Of 1,298 randomized and treated patients, 866 receiving TAF (DB and OL) and 432 receiving TDF with rollover to OL TAF at year 2 (n = 180; TDF→TAF3y) or year 3 (n = 202; TDF→TAF2y) were included. Fifty (4%) TDF patients who discontinued during DB were excluded. At year 5, 85%, 83%, and 90% achieved HBV DNA <29 IU/mL (missing = failure) in the TAF, TDF→TAF3y, and TDF→TAF2y groups, respectively; no patient developed TAF or TDF resistance. Median estimated glomerular filtration rate (by using Cockcroft-Gault) declined <2.5 mL/min, and mean declines of <1% in hip and spine bone mineral density were seen at year 5 in the TAF group; patients in the TDF→TAF groups had improvements in these parameters at year 5 after switching to OL TAF. DISCUSSION: Long-term TAF treatment resulted in high rates of viral suppression, no resistance, and favorable renal and bone safety.