Maternal Antiviral Prophylaxis to Prevent Perinatal Transmission of Hepatitis B Virus in Thailand
Maternal Antiviral Prophylaxis to Prevent Perinatal Transmission of Hepatitis B Virus in Thailand
Chronic hepatitis B (CHB) infection is complicated by cirrhosis and liver cancer. In
 Thailand, 7% of adults are chronically infected by Hepatitis B virus (HBV). The risk of
 perinatal transmission of HBV is about 12% when a mother has a high HBV load in her plasma,
 even if her infant receive specific immunoglobulin and vaccine.

 The hypothesis of this study is that a potent antiviral, tenofovir, can decrease HBV load in
 HBV infected pregnant women and therefore reduce the risk of perinatal transmission/ Pregnant
 women participating in this study will receive tenofovir or placebo during the last trimester
 of pregnancy and two months postpartum. The risk of perinatal transmission will be compared
 between the two groups.

 The results of the study will help define policy to manage HBV infected pregnant women to
 prevent perinatal transmission.
This is a phase III, placebo controlled, double blind, randomized clinical trial to assess
 the efficacy and safety of tenofovir disoproxil fumarate (TDF) given from 28 weeks' gestation
 until 2 months postpartum to pregnant women with Hepatitis B (HB) virus (HBV) chronic
 infection and positive for HB s and e antigen to prevent perinatal transmission of HBV to
 their infants. All infants will receive HBV passive (HB specific immunoglobulin) and active
 (vaccine) immunization.

 Chronic hepatitis B (CHB) infection is complicated by cirrhosis and hepatocellular carcinoma
 (HCC), the 10th leading cause of death worldwide.

 In 2011, about 7% of adults in Thailand were HBsAg carriers. Infant hepatitis B (HB)
 immunization and HB immune globulin (HBIg) administered at birth effectively prevent most
 mother-to-child transmission (MTCT) of HBV. However, about 12% of mothers with high load of
 HBV transmit the virus to their infants, despite active and passive immunization.

 Studies have suggested that antiviral treatment at the end of pregnancy and during early
 postpartum can reduce the risk of transmission to the child. A potential limitation to this
 approach is the risk of hepatic disease exacerbation following discontinuation of antiviral
 treatment postpartum, and this risk has not been properly evaluated. No randomized clinical
 trials have adequately demonstrated the efficacy and safety of maternal antiviral treatment
 the prevention of mother to child transmission of HBV. This is the reason why this approach
 is not currently recommended by the Associations for the Study of Liver Diseases.

 We hypothesize that a potent antiviral, tenofovir, can decrease HBV viral load in HBV
 infected pregnant women and therefore reduce the risk of perinatal transmission, before
 infants are definitely protected by passive-active immunization. We also hypothesize that
 only moderate exacerbations of liver disease will be observed after discontinuation of a
 short antiviral course (5 months). While the primary objective of the study is to assess the
 efficacy of tenofovir versus placebo for the prevention of perinatal transmission, an
 important secondary objective is the assessment of the risk of postpartum hepatic disease
 exacerbation.

 Within 2 years, 328 women and their infants will be enrolled from public hospitals in
 Thailand and randomized to receive either tenofovir disoproxil fumarate or matching placebo
 from 28 weeks of pregnancy until 2 months postpartum. Mothers and infants will be followed
 until one year postpartum.

 The primary endpoint will be the detection of HBsAg and HBV DNA in infants at six months of
 life. An interim analysis will be conducted when half of the outcomes are available.
Inclusion Criteria:

 -  Pregnancy

 -  At least 18 years of age

 -  Negative Human Immunodeficiency Virus (HIV) serology

 -  Positive HBsAg and hepatitis B e antigen (HBeAg) tests

 -  Gestational age of 28 weeks (+ or - 10 days) as determined by obstetrician

 -  Alanine Aminotransferase (ALT)≤30 U/L, confirmed ≤60 U/L on a subsequent blood draw

 -  Agreeing to bring their infants at the planned study visits at one study site until
 one year after delivery and to inform the site investigators if they plan to move to
 another place and not be able to return to the clinic.

 -  Understanding the need for adequate infant immunization and agreeing to the blood
 draws from their infants and the need for close follow up to manage possible
 exacerbation of hepatitis.

 Exclusion Criteria:

 -  History of tenofovir treatment at any time, or any other anti-HBV treatment during the
 current pregnancy

 -  Creatinine clearance <50 ml/min, calculated using the Cockcroft-Gault formula

 -  Dipstick proteinuria>1+ (>30 mg/dL) or normoglycemic glucosuria confirmed on two
 separate occasions

 -  Positive serology for Hepatitis C infection less than 12 months prior to enrollment

 -  Evidence of pre-existing fetal anomalies incompatible with life

 -  Any concomitant condition or treatment that, in the view of the clinical site
 investigator, would contraindicate participation or satisfactory follow up in the
 study.

 -  Concurrent participation in any other clinical trial without written agreement of the
 two study teams