Pregnant women who received tenofovir disoproxil fumarate and other prevention measures did not experience a significantly lower rate of transmission of hepatitis B compared to pregnant women who received placebo, according to findings recently published in The New England Journal of Medicine.
“Antiviral agents that inhibit HBV replication, such as lamivudine, tenofovir disoproxil fumarate and telbivudine, which have been administered to pregnant women with a high HBV viral load, may reduce the risk of mother-to-child transmission,” Gonzague Jourdain, MD, PhD, the Institut de Recherche pour le Développement Unité Mixte Internationale 174–Program for Health, Prevention, and Treatment, Thailand, and colleagues wrote.
Researchers added that WHO does not recommend this approach due to a lack of high-quality evidence regarding benefits and harms. Conversely, the American Association for the Study of Liver Diseases recommends antiviral therapy in pregnant women who are hepatitis B surface antigen (HBsAg)–positive and have a HBV DNA level of more than 200,000 IU/mL even though the evidence is uncertain and low quality.
Researchers randomly grouped 168 pregnant women in Thailand who were hepatitis B e antigen positive with an alanine aminotransferase level lower than 60 IU per liter to receive tenofovir disoproxil fumarate. Another 163 women who met these same criteria received placebo. Both groups of women received their respective medication from the time they were 28 weeks pregnant until 2 months after they gave birth. Offspring were given the hepatitis B immune globulin and HBV vaccine at birth, and the HBV vaccine again at 1, 2, 4, and 6 months.
Jourdain and colleagues reported that none of the 147 infants (0%; 95% CI, 0–2) in the tenofovir disoproxil fumarate group were infected while three of the 147 infants (2%; 95% CI, 0–6) in the placebo group were (P = .12). Maternal alanine aminotransferase levels greater than 300 IU per liter after stopping the trial regimen occurred in 6% in the tenofovir disoproxil fumarate group and 3% in the placebo group (P = .29). The rate of adverse events did not differ significantly between groups.
“A limitation of recent perinatal HBV infection–prevention studies has been the assumptions that were used to calculate the sample size. We calculated the sample size to provide the trial with more than 90% power to detect a difference of 9 percentage points in the rate of transmission (expected rate, 3% in the TDF group vs. 12% in the placebo group),” researchers wrote. “A superiority trial assessing a difference of 1.9 percentage points (0.1% vs. 2%) with 90% power would require a sample of more than 1600 mother–infant pairs, but feasibility might be limited as the use of antiviral treatment in this context increases.” – by Janel Miller
Healio Family Medicine was unable to determine the authors’ relevant financial disclosures prior to publication.