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TDF therapy in pregnancy reduces HBV DNA, risk of vertical transmission

Viremic mothers treated with tenofovir disoproxil fumarate during pregnancy had decreased hepatitis B virus infection DNA levels in their blood, which reduced the infection’s DNA serum levels in infants at birth and reduced overall mother-to-child transmission, according to study data.

“We conducted this clinical trial with the aims of evaluating the efficacy of [tenofovir disoproxil fumarate] administration initiated at 30 [to] 32 weeks of gestation in highly viremic pregnant mothers, assessing the efficacy in reducing mother-to-infant HBV transmission, and monitoring safety for the mothers and infants during pregnancy and the postpartum period,” the researchers wrote.

In a prospective trial, researchers enrolled 118 pregnant women between 20 and 40 years of age who were positive for hepatitis B surface antigen (HBsAg) and hepatitis B e antigen (HBeAg) with HBV DNA levels at or greater than 7.5 log₁₀ IU/mL. Each patient was randomly assigned to either no medication (n = 56) or 300 mg of tenofovir disoproxil fumarate (TDF) per day between 30 and 32 weeks of gestation until 1 month after birth (n = 62).

The primary outcome was to determine the infant’s rate of HBsAg at 6 months old, according to the research.

The women in the TDF group had lower maternal HBV DNA levels at infant delivery compared with the control group (4.29 ± 0.93 vs. 8.1 ± 0.56 log₁₀ IU/mL; P < .0001). The duration of treatment positively correlated with the reduced viral loads.

“At the time of delivery, [1.79%] of mothers in the control group and [98.39%] of mothers in the TDF group had HBV DNA levels below 6 log₁₀ IU/mL, a level considered to indicate minimal risk for maternal HBV transmission,” the researchers wrote.

Of 121 newborns, the babies in the TDF group had lower rates of HBV DNA positivity at birth compared with the control group (6.15% vs. 31.48%; P = .0003), as well as lower HBsAg positivity at 6 months old compared with the control group (1.54% vs. 10.71%; P = .0481).

Multivariate analysis showed that infants in the TDF group had lower risk of HBV DNA positivity (P = .0434). In addition, it showed amniocentesis to be associated with an increased risk of infant HBsAg positivity (P = .022).

Women in the TDF group had less incidence of alanine aminotransferase levels above two times the upper limit of normal for 3 or more months compared with the control group (3.23% vs. 14.29%; P = .0455); a lower rate of ALT over five times the upper limit of normal at 2 months postpartum compared with the controls (1.64% vs. 14.29%; P = .0135); and decreased postpartum elevations of ALT (P = .007).

Creatinine and creatinine kinase levels of the mother, rates of congenital anomaly, premature birth and growth parameters in infants were comparable in both the treated and control groups. Treatment was well tolerated. One month post-treatment, HBV viral loads increased among mothers in the treated group. The HBV DNA serum levels were comparable to the control group patients at 4 and 6 months postpartum.

At 12 months, one child whose mother was treated with TDF developed HBsAg positivity due to postnatal infection and inefficient humoral responses to vaccines, according to the research.

“Our study demonstrates that short-term TDF treatment leads to fast and effective reduction in HBV DNA in highly viremic HBsAg/HBeAg double-positive mothers,” the researchers concluded. “Such treatment resulted in decreased rates of serum HBV DNA positivity in the newborns’ peripheral blood and HBsAg positivity in the infants at 6 months of age.” – by Melinda Stevens

Disclosures: Chen reports no relevant financial disclosures. Please see the study for a full list of all other authors’ relevant financial disclosures.