Very high concentrations of active intracellular phosphorylated emtricitabine in neonates (ANRS 12109 trial, step 2).

Our objective was to investigate neonatal emtricitabine (FTC) plasma and intracellular pharmacokinetics. The study was designed as a phase I/II prospective trial in two sequential steps evaluating the combination of tenofovir disoproxil fumarate (TDF) and FTC for the prevention of mother-to-child-transmission (PMTCT) of HIV. HIV-1-infected pregnant women received two tablets of TDF (300 mg) and FTC (200 mg) at onset of labor and then one tablet daily for 7 days postpartum. Based on the data obtained in the first part of the Tenofovir/Emtricitabine in Africa and Asia (TEmAA) Study, single doses of 2 mg/kg of FTC and 13 mg/kg of TDF were given to the neonates within 12 h after birth. A total of 540 FTC plasma concentrations and 44 active intracellular phosphorylated metabolite FTC-TP concentrations were taken from the 36 enrolled women and their neonates. Concentrations were measured by the liquid chromatography-tandem mass spectrometry (LC-MS/MS) method and analyzed by a population approach. The proposed dose obtained by simulations based on plasma drug concentrations was confirmed. However, median FTC-TP exposures were, respectively, 5.9 and 6.8 times higher in the fetus and the neonate than in the adult. High FTC-TP concentrations were observed in the four children who had serious adverse events (SAEs), but the link between FTC-TP concentrations and SAEs in children was not formally identified. The exposure to the active form of FTC was high in neonates despite plasma drug concentrations equivalent to those in adults. Our results are similar to those obtained with zidovudine or lamivudine.

Reverse transcriptase mutations in Cambodian CRF01_AE isolates after antiretroviral prophylaxis against HIV Type 1 perinatal transmission.

This study explores amino acid changes of the reverse transcriptase (rt) of CRF01_AE isolates from pregnant women naive to antiretroviral drugs before and 2, 6, and 52 weeks after exposure to single dose nevirapine (sdNVP). Results based on 51 observations showed that the proportion of isolates with nonnucleoside reverse transcriptase inhibitor (NNRTI) RMs in the group treated with sdNVP (n = 35) increased from 0% pre-NVP to 22.9% at week 2 postpartum (pp) and 22.9% at week 6 pp. In the group treated with zidovudine + sdNVP (n = 16), the proportion with RM was 31.3% and 18.8% at weeks 2 and 6 pp, respectively. Only a few RMs were still detected at week 52 pp. No apparent subtype-specific treatment-related mutations were detected. NNRTI RM occurrence in CRF01_AE strains is similar to subtype A, D, and CRF02_AG strains after exposure to antiretroviral drugs for PMTCT.

Characterization of mutations in HIV type 1 isolates from 144 Cambodian recently infected patients and pregnant women naive to antiretroviral drugs.

A baseline study has been conducted to determine the polymorphism of reverse transcriptase, protease, and envelope genes of HIV-1 isolates from 146 antiretroviral drug-naive Cambodian patients including 22 seroconverters and 124 pregnant women having been diagnosed HIV positive for less than 1 year. Amplification of at least one gene was successful for 144 isolates. All three genes were obtained for 136 isolates. Subtyping showed that CRF01_AE was predominant (130 cases). According to the ANRS September 2004 list, polymorphism substitutions (>50% versus the subtype B consensus) of CRF01_AE at drug resistance positions were observed only in protease: I13V (81%), E35D (87%), M36I (100%), R41K (96%), and H69K (100%). Two strains bore one major resistance mutation to PIs: M46I and N88D. Five other strains carried drug resistance mutations to RTIs: K70R (one strain), V75M (three strains), and K101E (one strain). Of the isolates 4.9% had drug resistance mutations to antiretroviral drugs.

Maternal and nenonatal tenofovir and emtricitabine to prevent vertical transmission of HIV-1: tolerance and resistance.

OBJECTIVE: Viral resistance occurs with a high frequency after single-dose nevirapine. We aimed to evaluate the tolerance and resistance profiles of a combination of tenofovir disoproxil fumarate (TDF) and emtricitabine (FTC) given to HIV-1-infected delivering women and their newborns. DESIGN: An open-label phase I/II trial in Cambodia, Côte d'Ivoire and South Africa. METHODS: HIV-1-infected pregnant women received zidovudine from the enrollment until the beginning of labor, when single-dose nevirapine and two tablets of TDF/FTC were given. One daily tablet of TDF/FTC was then administered for 7 days postpartum. All infants received single-dose nevirapine with single-dose TDF (13 mg/kg) and single-dose FTC (2 mg/kg) and 1 week of zidovudine. Mothers and infants were followed for 2 months. Serious adverse events, kinetic of maternal plasma HIV-1 RNA, pediatric HIV infection and genotypic resistance and viral subtype were assessed. RESULTS: Thirty-six HIV-1-infected pregnant women were enrolled: median age 28 years (interquartile range: 26-31 years), median CD4 cell count 462 cells/µl (interquartile range: 376-632) and median HIV-1 RNA 3.7 log10 copies/ml (interquartile range: 2.95-4.11). Two infants had clinical serious adverse events, including one who died (neonatal sepsis). One transient grade 3 neutropenia and two grade 3/4 hyperbilirubinemia were also reported in neonates. One HIV pediatric in-utero infection was diagnosed (2.8%; 95% confidence interval 0-15.4%). Genotypic viral resistance to nevirapine was detected in one mother out of 34 (2.9%) at one month postpartum, but was also detectable at enrollment. CONCLUSION: The combination of TDF/FTC to delivering women and their neonates appears well tolerated and to minimize the occurrence of nevirapine viral resistance.

Tolerance and viral resistance after single-dose nevirapine with tenofovir and emtricitabine to prevent vertical transmission of HIV-1.

OBJECTIVE: Viral resistance occurs with high frequency after single-dose nevirapine. We aimed to evaluate the safety and resistance profiles of a combination of tenofovir disoproxil fumarate (TDF) and emtricitabine (FTC) in HIV-1-infected pregnant women and their newborns. DESIGN: An open-label phase I/II trial in Côte d'Ivoire, Cambodia and South Africa. METHODS: Women received antenatal zidovudine, intrapartum single-dose nevirapine and two tablets of TDF/FTC and one daily tablet of TDF/FTC during the 7 days postpartum. Their infants received single-dose nevirapine and zidovudine for 1 week. Serious adverse events (SAEs), kinetic of maternal plasma HIV-1 RNA viral load, genotypic resistance at 28 days postpartum and paediatric HIV-1 infection at 3, 28 and 45 days of life were assessed. RESULTS: Thirty-eight HIV-1-infected pregnant women were enrolled (19 in Abidjan, 12 in Phnom Penh and seven in Soweto) with a median CD4 cell count of 450 cells/microl and median viral load of 4.08 log10 copies/ml. Women received TDF/FTC 4.9 h in median before delivery. Biological SAEs occurred in nine women. Among 39 live births, nine infants had clinical SAEs, including four deaths, and two developed severe anaemia. These SAEs were not likely to be related to TDF/FTC. Maternal viral load decreased by a median of 0.90 log10 copies/ml at 2 days postpartum and returned to baseline value at 28 days. No intrapartum HIV transmission was reported. No genotypic resistance mutation to zidovudine, nevirapine, FTC or TDF was detected. CONCLUSION: The TDF/FTC combination was well tolerated in delivering women and exposed newborns. Nevirapine viral resistance appears to have been avoided by the intrapartum and 7-day postpartum TDF/FTC regimen.