SAN FRANCISCO, CA—Treatment with tenofovir disoproxil fumarate (TDF) in late pregnancy in highly viremic mothers with hepatitis B virus (HBV) infection effectively reduced mother-to-child transmission, a study reported at The Liver Meeting® 2015.

“The treatment was well tolerated, and no safety concerns were identified,” Calvin Pan, MD, Division of Gastroenterology and Hepatology, NYU Langone Medical Center, NYU School of Medicine, New York, NY, and colleagues have found.

They recommended that TDF “be strongly considered for mothers whose HBV DNA levels exceed 200,000 IU/mL,” with treatment be initiated at gestation Week 30–32.

Dr. Pan noted that data on using such agents to prevent mother-to-child transmission of HBV “are scarce. The investigators conducted a multi-center, prospective, randomized controlled study in 5 US regions in which hepatitis B e antigen (HBeAg)-positive mothers with HBV DNA levels >200,000 IU/mL were randomly assigned 1:1 to receive TDF from gestation Week 30–32 to postpartum Week 4 (n=97) or no treatment (n=100).

The mothers were followed until postpartum Week 28, and all infants received immunoprophylaxis.

The primary outcome was mother-to-child transmission rate; endpoints included safety with TDF, maternal HBV DNA reduction at delivery, and HBeAg or hepatitis B s antigen loss/seroconversion at postpartum Week 28. A total of 180 mothers completed the study.

“At postpartum Week 28, the mother-to-child transmission rate was significantly lower in infants from TDF-treated mothers when compared to those from non-treated mothers,” they reported. This was observed in both the per-protocol analysis set (0% vs. 6.82%, P=0.013) and the intention-to-treat analysis set (5.16% vs. 18.0%, P=0.007).

The safety profile was similar between the two groups, with no difference in birth defect rates: 2.11% with TDF exposure vs. 1.14% without exposure (P=1.00).

In the TDF-treated mothers, HBV DNA levels decreased to <200,000 IU/mL in 68% prior to delivery, compared with 2.0% (2/100) in non-treated mothers (P<0.001). “The HBV serologic outcome did not differ between groups,” they concluded.