Pregnant women with an elevated viral load of hepatitis B virus (HBV) have a risk of transmitting infection to their infants, despite the infants’ receiving hepatitis B immune globulin.
In this multicenter, double-blind clinical trial performed in Thailand, Dr Gonzague Jourdain randomly assigned hepatitis B e antigen (HBeAg)–positive pregnant women with an alanine aminotransferase level of 60 IU or less per liter to receive tenofovir disoproxil fumarate (TDF) or placebo from 28 weeks of gestation to 2 months post partum.
Infants received hepatitis B immune globulin at birth and hepatitis B vaccine at birth and at 1, 2, 4, and 6 months.
The team's primary end point was a hepatitis B surface antigen (HBsAg)–positive status in the infant, confirmed by the HBV DNA level at 6 months of age.
|The median gestational age was 28 weeks|
|New England Journal of Medicine|
The research team calculated that a sample of 328 women would provide the trial with 90% power to detect a difference of at least 9 percentage points in the transmission rate.
From 2013 to 2015, the researchers enrolled 331 women; 168 women were randomly assigned to the TDF group and 163 to the placebo group.
At enrollment, the median gestational age was 28 weeks, and the median HBV DNA level was 8.0 log10 IU per milliliter.
Among 322 deliveries, the team identified 319 singleton births, 2 twin pairs, and 1 stillborn infant.
The team observed that the median time from birth to administration of hepatitis B immune globulin was 1.3 hours, and the median time from birth to administration of hepatitis B vaccine was 1.2 hours.
In the primary analysis, the researchers noted that none of the 147 infants in the TDF group were infected, as compared with 3 of 147 in the placebo group.
The research team found that the rate of adverse events did not differ significantly between groups.
The incidence of a maternal alanine aminotransferase level of more than 300 IU per liter after discontinuation of the trial regimen was 6% in the TDF group, and 3% in the placebo group.
Dr Jourdain's team concludes, "In a setting in which the rate of mother-to-child HBV transmission was low with the administration of hepatitis B immune globulin and hepatitis B vaccine in infants born to HBeAg-positive mothers, the additional maternal use of TDF did not result in a significantly lower rate of transmission."