Efficacy of maternal tenofovir disoproxil fumarate in interrupting mother-to-infant transmission of hepatitis B virus

The efficacy and safety of maternal tenofovir disoproxil fumarate (TDF) in reducing mother-to-infant hepatitis B virus (HBV) transmissions is not clearly understood. We conducted a prospective, multicenter trial and enrolled 118 hepatitis B surface antigen (HBsAg)- and hepatitis B e antigen-positive pregnant women with HBV DNA 7.5 log(10) IU/mL. The mothers received no medication (control group, n=56, HBV DNA 8.22 +/- 0.39 log(10) IU/mL) or TDF 300 mg daily (TDF group, n=62, HBV DNA 8.18 +/- 0.47 log(10) IU/mL) from 30-32 weeks of gestation until 1 month postpartum. Primary outcome was infant HBsAg at 6 months old. At delivery, the TDF group had lower maternal HBV DNA levels (4.29 +/- 0.93 versus 8.10 +/- 0.56 log(10) IU/mL, P<0.0001). Of the 121/123 newborns, the TDF group had lower rates of HBV DNA positivity at birth (6.15% versus 31.48%, P = 0.0003) and HBsAg positivity at 6 months old (1.54% versus 10.71%, P = 0.0481). Multivariate analysis revealed that the TDF group had lower risk (odds ratio=0.10, P = 0.0434) and amniocentesis was associated with higher risk (odds ratio 6.82, P = 0.0220) of infant HBsAg positivity. The TDF group had less incidence of maternal alanine aminotransferase (ALT) levels above two times the upper limit of normal for 3 months (3.23% versus 14.29%, P = 0.0455), a lesser extent of postpartum elevations of ALT (P = 0.007), and a lower rate of ALT over five times the upper limit of normal (1.64% versus 14.29%, P = 0.0135) at 2 months postpartum. Maternal creatinine and creatinine kinase levels, rates of congenital anomaly, premature birth, and growth parameters in infants were comparable in both groups. At 12 months, one TDF-group child newly developed HBsAg positivity, presumably due to postnatal infection and inefficient humoral responses to vaccines. Conclusions: Treatment with TDF for highly viremic mothers decreased infant HBV DNA at birth and infant HBsAg positivity at 6 months and ameliorated maternal ALT elevations. (Hepatology 2015;62:375-386