Evaluation of the Use of Antiretroviral Regimens Containing Raltegravir for Prophylaxis of Mother-to-child-transmission of HIV Infection in Pregnant Women Presenting With Detectable Viral Load After 32 Weeks of Gestation: a Pilot Study

The current available antiretroviral (ARV) agents make possible a successful treatment of virtually all HIV-infected patients, even those heavily experienced subjects, with a history of previous failure to ARV drugs of different classes. However, some problems are still present, especially for specific populations, like pregnant women and infants. For these groups, most of currently available drugs are not used, because the lack of information on safety, efficacy, and pharmacokinetic/dynamic behavior of ARVs drugs. The mother to child transmission (MTCT) is still a problem in certain areas of the world, especially in resource-limited settings. In some settings, women often present to their first antenatal care visit late in the pregnancy, posing an additional problem: how to effectively treat these patients to assure they will have an undetectable viral load at the moment of delivering? Depending on the plasma viremia magnitude, and viral susceptibility it can take 6 or more weeks to reduce the viral load to less than the desired 1,000 copies of HIV-1 RNA / ml of plasma. To achieve this goal, it would be necessary the use of a potent, very efficacious ARV regimen that could provide such viral decay in a very short period. Raltegravir (RAL), the first HIV-1 integrase inhibitor, is a potent and safe ARV drug. The available evidence suggest it has no genotoxic potential, and promotes a rapid decline in HIV-1 plasma viremia. In addition, RAL is highly active against viral strains presenting different degree of resistance to other ARV drugs. Thus, RAL could be an ideal candidate to be used for prevention of MTCT for women with detectable viral load, presenting late in the course of pregnancy. Another attractive point is to consider that, due to the similarity between the integrase enzyme of HIV-1 and Human T-cell lymphotropic virus type-1 (HTLV-1); RAL could be active against HTLV-1, blocking its replication. If our hypothesis is correct, the use f RAL-containing ARV regimens would reduce the MTCT of both agents. This study has the objective of evaluating the efficacy of RAL containing ARV regimens in reducing the HIV-1 RNA plasma viral load below 50 copies/ml, at the end of pregnancy, for late-presenters pregnant women and to compare the frequency of adverse events for women using RAL-based ARV regimens and comparators, and for their babies.