No dose adjustment is needed for pregnant women who are receiving tenofovir disoproxil fumarate (TDF) to prevent mother-to-child transmission of hepatitis B virus (HBV), according to a study published in Antimicrobial Agents and Chemotherapy.1
Worldwide in 2015, approximately 257 million people were living with chronic HBV infection,2 with the majority of new cases occurring through mother-to-child transmission.3 Antiviral therapy starting at 28 to 32 weeks of pregnancy and continued through the early postpartum period is recommended for women who are positive for hepatitis B surface antigen to prevent transmission to their infants,4 and TDF is the preferred anti-HBV drug to use during pregnancy.5 Previous studies have demonstrated that plasma tenofovir exposure is lower during pregnancy when TDF is administered with antiretroviral therapy in women infected with HIV,6,7 but no data exist on tenofovir exposure during pregnancy and postpartum in HBV-infected women who are not infected with HIV and are receiving TDF alone.
Therefore, researchers evaluated data from 154 hepatitis B surface antigen-positive, HIV-uninfected women in Thailand who received TDF 300 mg once daily from 28 weeks gestation to 2 months postpartum as part of a phase 3, randomized, double-blind, placebo-controlled trial.1,8 They found that the estimated geometric mean plasma tenofovir exposure was 20% lower as a result of higher creatinine clearance during pregnancy compared with postpartum levels, however, no mothers transmitted HBV to their infants.1
This was the first study conducted on the pharmacokinetics of tenofovir in HIV-uninfected pregnant women receiving TDF to prevent mother-to-child transmission of HBV.1 Researchers concluded that, “the modest reduction in TFV exposures observed during pregnancy does not suggest a dose adjustment is necessary.”
- Cressey TR, Harrison L, Achalapong J, et al. Tenofovir exposure during pregnancy and postpartum in women receiving tenofovir disoproxil fumarate for the prevention of mother-to-child transmission of hepatitis B virus [published online October 1, 2018]. Antimicrob Agents Chemother. doi:10.1128/AAC.01686-18
- World Health Organization. Global hepatitis report, 2017. http://www.who.int/hepatitis/publications/global-hepatitis-report2017/en/. April 2017. Accessed October 12, 2018.
- Lavanchy D. Hepatitis B virus epidemiology, disease burden, treatment, and current and emerging prevention and control measures. J Viral Hepat. 2004;11:97-107.
- Lampertico P, Agarwal K, Berg T, et al; European Association for the Study of the Liver. EASL 2017 Clinical practice guidelines on the management of hepatitis B virus infection. J Hepatol. 2017;67:370-398.
- Terrault NA, Lok ASF, McMahon BJ, et al. Update on prevention, diagnosis, and treatment of chronic hepatitis B: AASLD 2018 hepatitis B guidance. Hepatology. 2018;67:1560-1599.
- Best BM, Burchett S, Li H, et al. Pharmacokinetics of tenofovir during pregnancy and postpartum. HIV Med. 2015;16:502-511.
- Colbers APH, Hawkins DA, Gingelmaier A, et al. The pharmacokinetics, safety and efficacy of tenofovir and emtricitabine in HIV-1-infected pregnant women. AIDS. 2013;27:739-748.
- Jourdain G, Ngo-Giang-Huong N, Harrison L, et al. Tenofovir versus placebo to prevent perinatal transmission of hepatitis B. N Engl J Med. 2018;378:911-923.