Safety Study of a Tenofovir-containing Drug Regimen for the Prevention of Mother-to-child Transmission of HIV and HBV (TiP)

• Tenofovir Safety for mothers measured by incidence of serious adverse events (SAEs) [ Time Frame: From baseline (14-28 weeks gestation) through 12 months postpartum ] [ Designated as safety issue: Yes ]
  SAEs will be defined using the DAIDS Toxicity Tables
  
  
• Dual Energy X-ray absorptiometry (DXA) scans of bone mineral density [ Time Frame: from delivery through 6 months postpartum ] [ Designated as safety issue: Yes ]
  Mothers will have DXA scan of hip and lumbar spine. Infants will have DXA scan of whole body and lumbar spine.
  
  
• Maternal Tenofovir Pharmacokinetics [ Time Frame: 16 weeks gestation through delivery ] [ Designated as safety issue: Yes ]
  Only for mothers on the active arm.
  
  
• Infant Tenofovir Pharmacokinetics [ Time Frame: one timepoint within 12 hours of delivery ] [ Designated as safety issue: Yes ]
  Only for infants on the active arm.
  
  
• Tenofovir safety for infants measured by incidence of serious adverse events (SAEs) [ Time Frame: from birth through 12 months of age ] [ Designated as safety issue: Yes ]
  SAEs defined according to the DAIDS toxicity tables.
  
  

• HBV viral load in mothers [ Time Frame: from baseline (14-28 weeks gestation) through delivery ] [ Designated as safety issue: No ]
  
• Infant HIV transmission rate [ Time Frame: birth through 12 months ] [ Designated as safety issue: No ]
  
• Infant HBV transmission rate [ Time Frame: birth through 12 months ] [ Designated as safety issue: No ]
  
• Prevalence of HIV resistance mutations [ Time Frame: from baseline (14-28 weeks gestation) through 12 months postpartum ] [ Designated as safety issue: No ]
  
• Prevalence of HBV resistance mutations [ Time Frame: from baseline (14-28 weeks gestation) through 12 months postpartum ] [ Designated as safety issue: No ]
  

Great progress has been made in preventing mother-to-child transmission (MTCT) of HIV in resource-rich settings with the use of combination antiretroviral regimens during pregnancy and peripartum. In the resource-limited world simple inexpensive regimens administered peripartum, such as single dose nevirapine to mothers and infants, have been effective in reducing transmission but at the cost of development of resistance. Strategies that will allow women to preserve their antiretroviral options when they will need therapy for their own HIV disease and will improve efficacy are urgently needed. Moreover, co-infection with hepatitis B virus (HBV) is a problem for a substantial proportion of HIV-infected pregnant women. HIV alters the course of HBV disease by increasing levels of HBV DNA replication and thus risk of transmission to the newborn. HBV immunization in the infant with the first dose started soon after birth has decreased the bulk of such transmission, but the risk remains, particularly for mothers with HBe antigen positivity. Ideally an antiviral regimen administered during pregnancy with activity against both viruses would minimize transmission of both HIV and HBV to the infant.

The investigators propose to study a combination of tenofovir/lamivudine/lopinavir-ritonavir started between 14 and 28 weeks of pregnancy in HIV and HBV co-infected women. This regimen provides potent antiviral activity for prevention of MTCT. In addition, tenofovir and lamivudine both have activity against HBV, and could play a role in decreasing transmission of HBV to the infant. This regimen will be compared to the WHO-recommended and locally practiced standard of care, consisting of zidovudine/lamivudine/lopinavir-ritonavir, also starting at 14-28 weeks of pregnancy. This will be a phase II study evaluating the safety of the test regimen in pregnant women and their newborns, in particular renal, bone mineral density and hepatic toxicity (including hepatic flares post discontinuation of therapy). The study will recruit 80 pregnant women of at least 20 years of age in China and follow them and their infants for 12 months post-delivery. The investigators will recruit from prenatal clinics in some of the districts most heavily affected by HIV in the Guangxi province in China. China is selected for this study as it is hyperendemic for hepatitis B and has a rising HIV epidemic. Although not powered to examine efficacy, preliminary estimates of transmission of HIV and HBV to the infants and of the rate of resistance development will be obtained. The study will be done in collaboration with CDC-GAP China and the Chinese Ministry of Health-National Center for AIDS, which will coordinate recruitment, study visits and data collection through the local HIV/AIDS coordinators.