Efficacy and safety of 1-month postpartum zidovudine-didanosine to prevent HIV-resistance mutations after intrapartum single-dose nevirapine

Essential components of postnatal care - a systematic literature review and development of signal functions to guide monitoring and evaluation

BACKGROUND

Postnatal Care (PNC) is one of the healthcare-packages in the continuum of care for mothers and children that needs to be in place to reduce global maternal and perinatal mortality and morbidity. We sought to identify the essential components of PNC and develop signal functions to reflect these which can be used for the monitoring and evaluation of availability and quality of PNC.

METHODS

Systematic review of the literature using MESH headings for databases (Cinahl, Cochrane, Global Health, Medline, PubMed, and Web of Science). Papers and reports on content of PNC published from 2000-2020 were included. Narrative synthesis of data and development of signal function through 7 consensus-building workshops with 184 stakeholders.

RESULTS

Forty-Eight papers and reports are included in the systematic review from which 22 essential components of PNC were extracted and used to develop 14 signal functions. Signal functions are used in obstetrics to denote a list of interventions that address major causes of maternal and perinatal morbidity or mortality. For each signal function we identified the equipment, medication and consumables required for implementation. The prevention and management of infectious diseases (malaria, HIV, tuberculosis) are considered essential components of routine PNC depending on population disease burden or whether the population is considered at risk. Screening and management of pre-eclampsia, maternal anaemia and mental health are recommended universally. Promotion of and support of exclusive breastfeeding and uptake of a modern contraceptive method are also considered essential components of PNC. For the new-born baby, cord care, monitoring of growth and development, screening for congenital disease and commencing vaccinations are considered essential signal functions. Screening for gender-based violence (GBV) including intimate partner- violence (IPV) is recommended when counselling can be provided and/or a referral pathway is in place. Debriefing following birth (complicated or un-complicated) was agreed through consensus-building as an important component of PNC.

CONCLUSIONS

Signal functions were developed which can be used for monitoring and evaluation of content and quality of PNC. Country adaptation and validation is recommended and further work is needed to examine if the proposed signal functions can serve as a useful monitoring and evaluation tool.

TRIAL REGISTRATION

The systematic review protocol was registered: PROSPERO 2018 CRD42018107054 .

Zika Virus Immunoglobulin G Seroprevalence among Young Adults Living with HIV or without HIV in Thailand from 1997 to 2017

Zika virus (ZIKV) epidemiological data in Thailand are limited. We assessed ZIKV IgG seroprevalence among young adults during 1997–2017 and determined factors associated with ZIKV IgG seropositivity. This retrospective laboratory study included randomly selected subjects aged 18–25 years participating in large clinical studies conducted in Thailand during 1997–2017. Stored plasma samples were analyzed for ZIKV IgG using an ELISA test (Anti-Zika Virus IgG, EUROIMMUN, Lübeck, Germany). Sociodemographic, clinical and laboratory data were used in univariable and multivariable analyses to identify factors associated with ZIKV IgG positivity. Of the 1648 subjects included, 1259 were pregnant women, 844 were living with HIV and 111 were living with HBV. ZIKV IgG seroprevalence was similar among the HIV-infected and -uninfected pregnant women (22.8% vs. 25.8%, p-value = 0.335) and was overall stable among the pregnant women, with a 25.2% prevalence. Factors independently associated with ZIKV IgG positivity included an age of 23–25 years as compared to 18–20 years, an HIV RNA load below 3.88 log₁₀ copies/mL and birth in regions outside northern Thailand. Our study shows that a large proportion of the population in Thailand probably remains susceptible to ZIKV infection, which could be the ground for future outbreaks. Continued surveillance of ZIKV spread in Thailand is needed to inform public health policies.

Lack of Association between Adverse Pregnancy Outcomes and Zika Antibodies among Pregnant Women in Thailand between 1997 and 2015

Data about Zika virus infection and adverse pregnancy outcomes in Southeast Asia are scarce. We conducted an unmatched case-control study of Zika virus (ZIKV) serology in pregnant women enrolled in human immunodeficiency virus (HIV) or hepatitis B virus (HBV) perinatal prevention trials between 1997 and 2015 in Thailand. Case and control groups included women with and without adverse pregnancy outcomes. Plasma samples collected during the last trimester of pregnancy were tested for ZIKV IgG/IgM and Dengue IgG/IgM (Euroimmun, AG, Germany). Case newborn plasma samples were tested for ZIKV IgM and ZIKV RNA (Viasure, Spain). The case group included women with stillbirth (n = 22) or whose infants had microcephaly (n = 4), a head circumference below the first percentile (n = 14), neurological disorders (n = 36), or had died within 10 days after birth (n = 11). No women in the case group were positive for ZIKV IgM, and none of their live-born neonates were positive for ZIKV IgM or ZIKV RNA. The overall ZIKV IgG prevalence was 29%, 24% in the case and 34% in the control groups (Fisher's exact test; p = 0.13), while the dengue IgG seroprevalence was 90%. Neither neonatal ZIKV infections nor ZIKV-related adverse pregnancy outcomes were observed in these women with HIV and/or HBV during the 18-year study period.

Perinatal Antiretroviral Intensification to Prevent Intrapartum HIV Transmission When Antenatal Antiretroviral Therapy Is Initiated Less Than 8 Weeks Before Delivery

INTRODUCTION

Infants born to women living with HIV initiating combination antiretroviral therapy (cART) late in pregnancy are at high risk of intrapartum infection. Mother/infant perinatal antiretroviral intensification may substantially reduce this risk.

METHODS

In this single-arm Bayesian trial, pregnant women with HIV receiving standard of care antiretroviral prophylaxis in Thailand (maternal antenatal lopinavir-based cART; nonbreastfed infants 4 weeks' postnatal zidovudine) were offered "antiretroviral intensification" (labor single-dose nevirapine plus infant zidovudine-lamivudine-nevirapine for 2 weeks followed by zidovudine-lamivudine for 2 weeks) if their antenatal cART was initiated ≤8 weeks before delivery. A negative birth HIV-DNA polymerase chain reaction (PCR) followed by a confirmed positive PCR defined intrapartum transmission. Before study initiation, we modeled intrapartum transmission probabilities using data from 3738 mother/infant pairs enrolled in our previous trials in Thailand using a logistic model, with perinatal maternal/infant antiretroviral regimen and predicted viral load at delivery as main covariates. Using the characteristics of the women enrolled who received intensification, prior intrapartum transmission probabilities (credibility intervals) with/without intensification were estimated. After including the transmission data observed in the current study, the corresponding Bayesian posterior transmission probability was derived.

RESULTS

No intrapartum transmission of HIV was observed among the 88 mother/infant pairs receiving intensification. The estimated intrapartum transmission probability was 2·2% (95% credibility interval 0·5-6·1) without intensification versus 0·3% (0·0-1·6) with intensification. The probability of superiority of intensification over standard of care was 94·4%. Antiretroviral intensification appeared safe.

CONCLUSION

Mother/infant antiretroviral intensification was effective in preventing intrapartum transmission of HIV in pregnant women receiving ≤8 weeks antepartum cART.

A post-partum single-dose TDF/FTC tail does not prevent the selection of NNRTI resistance in women receiving pre-partum ZDV and intrapartum single-dose nevirapine to prevent mother-to- child HIV-1 transmission

Although the rates of vertical transmission of HIV in the developing world have improved to around 3% in countries like South Africa, resistance to antiretrovirals (ARV) used in Prevention of Mother‐to‐Child transmission (pMTCT) strategies may thwart such outcomes and affect the efficacy of future ARV regimens in mothers and children. This study conducted in Durban, South Africa, between 2010 and 2013 found a high rate of nevirapine (NVP) resistance among women receiving Zidovudine (AZT) from 14 weeks gestation, single dose nevirapine (sd NVP) at the onset of labor and a single dose of coformulated Tenofovir/Emtricitabine (TDF/FTC) postpartum. Using Sanger sequencing, high and intermediate levels of nevirapine (NVP) resistance were detected in 15/44 (34%) and in 1/44 (2%) of women tested, respectively. Most subjects selected the K103N mutation (22% (10/45) of all patients and 66% (10/15) of those with high‐level NVP resistance). Such rate of NVP resistance is comparable to studies where only sd NVP was used. In conclusion, a post‐partum single‐dose TDF/FTC tail does not prevent the selection of NNRTI resistance in women receiving pre‐partum ZDV and intrapartum sd NVP to prevent mother‐to‐child HIV‐1 transmission. J. Med. Virol. 87:1662–1667, 2015. © 2015 The Authors. Journal of Medical Virology published by Wiley Periodicals, Inc.

Comparison of anti-retroviral therapy treatment strategies in prevention of mother-to-child transmission in a teaching hospital in Ethiopia

BACKGROUND

More than 90% of Human immunodeficiency virus (HIV) infection in children is acquired due to mother-to-child transmission, which is spreading during pregnancy, delivery or breastfeeding.

OBJECTIVE

To determine the effectiveness of highly active antiretroviral and short course antiretroviral regimens in prevention of mother-to-child transmission of HIV and associated factors Jimma University Specialized Hospital (JUSH).

METHOD

A hospital based retrospective cohort study was conducted on HIV infected pregnant mothers who gave birth and had follow up at anti-retroviral therapy (ART) clinic for at least 6 months during a time period paired with their infants. The primary and secondary outcomes were rate of infant infection by HIV at 6 weeks and 6 months respectively. The Chi-square was used for the comparison of categorical data multivariate logistic regression model was used to identify the determinants of early mother-to-child transmission of HIV at 6 weeks. Cox proportional hazard model was used to analyze factors that affect the 6 month HIV free survival of infants born to HIV infected mothers.

RESULTS

A total of 180 mother infant pairs were considered for the final analysis, 90(50%) mothers received single dose nevirapine (sdNVP) designated as regimen-3, 67 (37.2%) mothers were on different types of ARV regimens commonly AZT + 3TC + NVP (regimen-1), while the rest 23 (12.8%) mothers were on short course dual regimen AZT + 3TC + sdNVP (regimen-2). Early mother-to-child transmission rate at 6 weeks for regimens 1, 2 and 3 were 5.9% (4/67), 8.6% (2/23), and 15.5% (14/90) respectively. The late cumulative mother-to-child transmission rate of HIV at 6 months regardless of regimen type was 15.5% (28/180). Postnatal transmission at 6 months was 28.5% (8/28) of infected children. Factors that were found to be associated with high risk of early mother-to-child transmission of HIV include duration of ARV regimen shorter than 2 months during pregnancy (OR=4.3, 95%CI =1.38-13.46), base line CD4 less than 350 cells/cubic mm (OR=6.98, 95%CI=0.91-53.76), early infant infection (OR=5.4, 95%CI=2.04-14.4), infants delivered home (OR=13.1, 95%CI=2.69-63.7), infant with birth weight less than 2500 g (OR=6.41, 95%CI=2.21-18.61), and mixed infant feeding (OR=6.7, 95%CI=2.2-20.4). Antiretroviral regimen duration less than 2 months, maternal base line CD4 less than 350 cells/cubic mm and mixed infant feeding were also important risk factors for late infant infection or death.

CONCLUSION

The effectiveness of multiple antiretroviral drugs in prevention of early mother-to-child transmission of HIV was found to be more effective than that of single dose nevirapine, although, the difference was not statistically significant. But in late transmission, a significant difference was observed in which infants born to mother who received multiple antiretroviral drugs were less likely to progress to infection or death than infants born to mothers who received single dose nevirapine.

Clinical and genetic determinants of plasma nevirapine exposure following an intrapartum dose to prevent mother-to-child HIV transmission

OBJECTIVE

Nevirapine is metabolized by cytochrome P450 (CYP) 2B6 and CYP3A4. We characterized relationships between clinical parameters, human genetics, pharmacokinetics, and human immunodeficiency virus type 1 (HIV-1) drug resistance mutations in pregnant women following single-dose intrapartum nevirapine.

METHODS

In AIDS Clinical Trials Group study A5207, women received nevirapine at onset of labor and were randomly assigned to receive lamivudine/zidovudine, emtricitabine/tenofovir, or lopinavir/ritonavir for 7 or 21 days. Plasma nevirapine level was quantified on postpartum day 1 and on weeks 1, 3, and 5. We assayed 214 polymorphisms in CYP2B6 and other genes and evaluated associations with pharmacokinetic parameters, including elimination constant, time to protein-adjusted 50% inhibitory concentration (IC50), and week 5 nevirapine level below the quantification limit.

RESULTS

Among 301 women with evaluable pharmacokinetic and genotype data, lower body mass index and random assignment to receive lopinavir/ritonavir were associated with more rapid nevirapine elimination. Among those of African ancestry, longer time to IC50 was associated with CYP2B6 983T → C (P = .004) but not with CYP2B6 516G → T (P = .8). Among Indians, slower nevirapine elimination was associated with CYP2B6 516G → T (P = .04). Emergent resistance was infrequent and not associated with pharmacokinetics or CYP2B6 genotype.

CONCLUSIONS

The effects on plasma drug exposure following single-dose nevirapine may be greater for CYP2B6 983T → C than for 516G → T and are less pronounced than at steady state.

Clinical implications of HIV-1 minority variants

Technologic advances in human immunodeficiency virus type 1 (HIV-1) sequencing have revolutionized the study of antiretroviral drug resistance and are increasingly moving from the laboratory to clinical practice. These techniques are able to detect HIV-1 drug resistance mutations present at low frequencies not detectable by current HIV-1 genotyping assays. For a number of commonly used antiretroviral medications, such as nonnucleoside reverse transcriptase inhibitors, the detection of these drug-resistant minority variants significantly increases the risk of treatment failure. The level of evidence, however, is insufficient to determine the impact of HIV-1 minority variants for several other classes of antiretroviral medications. Clinicians should be aware of the novel technologies that are moving into routine clinical use and the clinical implications of HIV-1 minority variants. Additional studies are needed to determine the optimal platform for clinical application of these new technologies and to provide guidance to clinicians on the type and frequency of clinically important HIV-1 minority variants.

NNRTIs: future prospects

The contribution of efavirenz and nevirapine remains clinically relevant and is the reason for the frequent prescription of these two agents. Recent clinical data on efavirenz and nevirapine in naive patients confirms their effectiveness compared to protease inhibitors such as lopinavir/r (ACTG 5142) or atazanavir/r (ACTG 5202) for efavirenz, or such as atazanavir/r (ARTEN trial) for nevirapine. Their easy use is another advantage; efavirenz is part of the first triple therapy as a single tablet given once a day, and nevirapine, with its new extended-release formulation, was designed for a single daily intake. However, the two agents exhibit different safety profiles and pharmacological properties. Their penetration rates in the genital tracts are different (70 to 80% for nevirapine versus 0 to 3% for efavirenz in men and 13-80% for nevirapine versus 0 to 4% for efavirenz in women). Finally, the authors of two recent studies reported the differences in the residual VL measured by ultrasensitive assays in successfully treated patients. The VL of patients treated with nevirapine was significantly more frequently below the detection limit of 1 or 2.5 RNA copies/mL than patients treated with efavirenz.

Intrapartum single-dose carbamazepine reduces nevirapine levels faster and may decrease resistance after a single dose of nevirapine for perinatal HIV prevention

BACKGROUND

World Health Organization guidelines recommend zidovudine + lamivudine for 7 days from labor onset in HIV-infected women receiving single-dose nevirapine (sdNVP) to cover prolonged subtherapeutic nevirapine concentrations. Although effective, this is complicated and does not eliminate resistance; alternative strategies could add benefit.

METHODS

Antiretroviral-naive HIV-infected pregnant women aged 18-40 years, with CD4 >200 cells per cubic millimeter, able to regularly attend the antenatal clinics in Moshi, Tanzania, were enrolled 1:1 by alternate allocation to receive 200 mg sdNVP alone or in combination with open-label 400-mg single-dose carbamazepine (sdNVP/CBZ) at delivery (ClinicalTrials.gov NCT00294892). The coprimary outcomes were nevirapine plasma concentrations 1 week and nevirapine resistance mutations 6 weeks postpartum. Analyses were based on those still eligible at delivery.

RESULTS

Ninety-seven women were assigned to sdNVP and 95 to sdNVP/CBZ during pregnancy, of whom 75 sdNVP and 83 sdNVP/CBZ were still eligible at delivery at study sites. The median (interquartile range) nevirapine plasma concentration was 1.55 (0.88-1.84) mg/L in sdNVP (n = 61) and 1.40 (0.93-1.97) mg/L in sdNVP/CBZ (n = 72) at delivery (P = 0.91), but 1 week later was significantly lower in sdNVP/CBZ [n = 63; 0.09 (0.05-0.20) mg/L] than in sdNVP [n = 52; 0.20 (0.09-0.31) mg/L; rank-sum: P = 0.004] (geometric mean ratio: 0.64, 95% confidence interval: 0.43 to 0.96; P = 0.03). Six weeks postpartum, nevirapine mutations were observed in 11 of 52 (21%) in sdNVP and 6 of 55 (11%) in sdNVP/CBZ (odds ratio = 0.46, 95% confidence interval: 0.16 to 1.34; P = 0.15).

CONCLUSIONS

Addition of single-dose carbamazepine to sdNVP at labor onset in HIV-infected, pregnant women did not affect nevirapine plasma concentration at delivery, but significantly reduced it 1 week postpartum, with a trend toward fewer nevirapine resistance mutations.

Standing genetic variation and the evolution of drug resistance in HIV

Drug resistance remains a major problem for the treatment of HIV. Resistance can occur due to mutations that were present before treatment starts or due to mutations that occur during treatment. The relative importance of these two sources is unknown. Resistance can also be transmitted between patients, but this process is not considered in the current study. We study three different situations in which HIV drug resistance may evolve: starting triple-drug therapy, treatment with a single dose of nevirapine and interruption of treatment. For each of these three cases good data are available from literature, which allows us to estimate the probability that resistance evolves from standing genetic variation. Depending on the treatment we find probabilities of the evolution of drug resistance due to standing genetic variation between and . For patients who start triple-drug combination therapy, we find that drug resistance evolves from standing genetic variation in approximately 6% of the patients. We use a population-dynamic and population-genetic model to understand the observations and to estimate important evolutionary parameters under the assumption that treatment failure is caused by the fixation of a single drug resistance mutation. We find that both the effective population size of the virus before treatment, and the fitness of the resistant mutant during treatment, are key-parameters which determine the probability that resistance evolves from standing genetic variation. Importantly, clinical data indicate that both of these parameters can be manipulated by the kind of treatment that is used.

For HIV patients who are treated with antiretroviral drugs, treatment usually works well. However, the virus can, and sometimes does, become resistant against one or more drugs. HIV drug resistance results from the acquisition of specific and well known mutations. It is currently unknown whether drug resistance mutations usually stem from standing genetic variation, i.e., they were already present at low frequency before treatment started, or whether they tend to occur during treatment. In the current manuscript, I make use of several large datasets and evolutionary modeling to estimate the probability that drug resistance mutations are present before treatment starts and lead to viral failure. I find that for the most common type of treatment with a combination of three drugs, drug resistance evolves from pre-existing mutations in 6% of the patients. With other types of treatment, this probability varies from 0 to 39%. I conclude that there is room for improvement in preventing the evolution of drug resistance from pre-existing mutations.

Selection of HIV resistance associated with antiretroviral therapy initiated due to pregnancy and suspended postpartum

OBJECTIVE

Compare the risk of HIV drug resistance in women stopping suppressive nelfinavir (NFV)-based or Nevirapine (NVP)-based antiretroviral therapy (ART) after pregnancy.

METHODS

Specimens collected after stopping ART were tested for drug resistance by an oligonucleotide ligation assay and consensus sequencing. When postpartum drug resistance was detected, specimens obtained at study entry and during ART were evaluated.

RESULTS

Sixteen of 38 women with ART-induced suppression of viral replication suspended ART postpartum. Resistance mutations were detected in 75% who stopped NFV-ART and in 50% who stopped NVP-ART. M184V, associated with Lamivudine resistance, was more frequent among those randomized to NFV-ART compared with NVP-ART (6 of 8 versus 1 of 8; P = 0.04), and nonnucleoside reverse transcriptase inhibitor resistance was detected in 4 of 8 stopping NVP-ART.

CONCLUSIONS

HIV drug resistance was frequently observed among women who stopped suppressive NVP-ART or NFV-ART postpartum. This suggests that NFV-ART may have suboptimal potency, that staggering discontinuation of NVP-ART may be warranted, and/or ART adherence may be lax in women who choose to stop ART postpartum.

A comparison of 3 regimens to prevent nevirapine resistance mutations in HIV-infected pregnant women receiving a single intrapartum dose of nevirapine

BACKGROUND

Intrapartum single-dose (SD) nevirapine (NVP) reduces perinatal transmission of human immunodeficiency virus (HIV) infection but selects for NVP-resistant virus, which compromises subsequent NVP-based therapy. A 1-week "tail" of lamivudine and zidovudine after SD-NVP decreases the risk of resistance. We hypothesized that increasing the duration or potency of the tail would further reduce this risk to <10%, using a sensitive assay to measure resistance.

METHODS

HIV-infected pregnant Thai women with a CD4 cell count >250 cells/μL, most receiving zidovudine, were randomized at 28-38 weeks gestation to receive 1 of 3 intrapartum and postpartum regimens: (A) zidovudine plus enteric-coated didanosine plus lopinavir and ritonavir for 7 days, (B) zidovudine plus enteric-coated didanosine for 30 days, or (C) regimen 1 for 30 days. The incidence of NVP resistance mutations at day 10 or week 6 post partum in each arm was compared with that of a historical comparison group who received prenatal zidovudine and SD-NVP. NVP resistance was identified by consensus sequencing and a sensitive oligonucleotide ligation assay (OLA).

RESULTS

At entry, the 169 participants had a median CD4 cell count of 456 cells/μL and an HIV load of 3.49 log(10) copies/mL. The incidence of mutations in each of the 3 P1032 arms was 0% by sequencing and 1.8%, 7.1%, and 5.3% by OLA in arms A, B, and C, respectively, compared with 13.4% by sequencing and 29.4% by OLA in the comparison group (P < .001 for each study arm vs comparison group). Grade 4 anemia developed in 1 woman.

CONCLUSIONS

A 7-day tail of highly active combination therapy or 1 month of dual therapy after SD-NVP prevents most NVP resistance to minimal toxicity.

CLINICAL TRIALS REGISTRATION

The IMPAACT P1032 Clinical Trial is NCT00109590, and the PHPT-2 Clinical Trial is NCT00398684.

Emergence and persistence of minor drug-resistant HIV-1 variants in Ugandan women after nevirapine single-dose prophylaxis

Background

Nevirapine (NVP) single-dose is still a widely used antiretroviral prophylaxis for the prevention of vertical HIV-1 transmission in resource-limited settings. However, the main disadvantage of the Non-nucleoside Reverse Transcriptase Inhibitor (NNRTI) NVP is the rapid selection of NVP-resistant virus with negative implications for subsequent NNRTI-based long-term antiretroviral therapy (ART). Here, we analysed the emergence of drug-resistant HIV-1 including minor variants in the early phase after NVP single-dose prophylaxis and the persistence of drug-resistant virus over time.

Methods and Findings

NVP-resistant HIV-1 harbouring the K103N and/or Y181C resistance mutations in the HIV-1 reverse transcriptase gene was measured from 1 week up to 18 months after NVP single-dose prophylaxis in 29 Ugandan women using allele-specific PCR assays capable of detecting drug-resistant variants representing less than 1% of the whole viral population. In total, drug-resistant HIV-1 was identified in 18/29 (62%) women; rates increased from 18% to 38% and 44% at week 1, 2, 6, respectively, and decreased to 18%, 25%, 13% and 4% at month 3, 6, 12 and 18, respectively. The proportion of NVP-resistant virus of the total viral population was significantly higher in women infected with subtype D (median 40.5%) as compared to subtype A (median 1.3%; p = 0.032, Mann-Whitney U test). 33% of resistant virus was not detectable at week 2 but was for the first time measurable 6–12 weeks after NVP single-dose prophylaxis. Three (10%) women harboured resistant virus in proportions >10% still at month 6.

Conclusions

Current WHO guidelines recommend an additional postnatal intake of AZT and 3TC for one week to avoid NVP resistance formation. Our findings indicate that a 1-week medication might be too short to impede the emergence of NVP resistance in a substantial proportion of women. Furthermore, subsequent NNRTI-based ART should not be started earlier than 12 months after NVP single-dose prophylaxis.

Role of low-frequency HIV-1 variants in failure of nevirapine-containing antiviral therapy in women previously exposed to single-dose nevirapine

In the OCTANE/A5208 study of initial antiretroviral therapy (ART) in women exposed to single-dose nevirapine (sdNVP) ≥ 6 mo earlier, the primary endpoint (virological failure or death) was significantly more frequent in the NVP-containing treatment arm than in the lopinavir/ritonavir-containing treatment arm. Detection of NVP resistance in plasma virus at study entry by standard population genotype was strongly associated with the primary endpoint in the NVP arm, but two-thirds of endpoints occurred in women without NVP resistance. We hypothesized that low-frequency NVP-resistant mutants, missed by population genotype, explained excess failure in the NVP treatment arm. Plasma samples from 232 participants were analyzed by allele-specific PCR at study entry to quantify NVP-resistant mutants down to 0.1% for 103N and 190A and to 0.3% for 181C. Of 201 women without NVP resistance by population genotype, 70 (35%) had NVP-resistant mutants detected by allele-specific PCR. Among these 70 women, primary endpoints occurred in 12 (32%) of 38 women in the NVP arm vs. 3 (9%) of 32 in the lopinavir/ritonavir-containing arm (hazard ratio = 3.84). The occurrence of a primary endpoint in the NVP arm was significantly associated with the presence of K103N or Y181C NVP-resistant mutations at frequencies >1%. The risk for a study endpoint associated with NVP-resistant mutant levels did not decrease with time. Therefore, among women with prior exposure to sdNVP, low-frequency NVP-resistant mutants were associated with increased risk for failure of NVP-containing ART. The implications for choosing initial ART for sdNVP-exposed women are discussed.

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.

Addition of 7 days of zidovudine plus lamivudine to peripartum single-dose nevirapine effectively reduces nevirapine resistance postpartum in HIV-infected mothers in Malawi

BACKGROUND

We assessed whether 7 days of zidovudine + lamivudine postpartum with single-dose nevirapine at labor decreases nevirapine resistance in HIV-infected women in Malawi.

METHODS

HIV-infected pregnant women receiving intrapartum single-dose nevirapine and 7 days of zidovudine + lamivudine (n = 132) and women receiving intrapartum single-dose nevirapine alone (n = 66) were followed from an antenatal visit through 6 weeks postpartum. Plasma specimens at 2 and 6 weeks postpartum were tested for genotypic resistance to nevirapine by population sequencing and sensitive real-time polymerase chain reaction. Poisson regression was used to determine predictors of postpartum nevirapine resistance.

RESULTS

Median HIV RNA was similar at entry (4.27 log vs. 4.35 log, P = 0.87), differed at 2 weeks postpartum (2.67 log vs. 3.58 log, P < 0.0001) but not at 6 weeks postpartum (4.49 log vs. 4.40 log, P = 0.79), between single-dose nevirapine/zidovudine + lamivudine and single-dose nevirapine groups, respectively. Nevirapine resistance, measured by population sequencing and sensitive real-time polymerase chain reaction, was significantly less common in those receiving single-dose nevirapine/zidovudine + lamivudine compared with single-dose nevirapine, respectively, at 2 weeks [10% (4 of 40) vs. 74% (31 of 42), P < 0.0001] and 6 weeks postpartum [10% (11 of 115) vs. 64% (41 of 64), P < 0.0001; adjusted relative risk = 0.18, 95% confidence interval (0.10 to 0.34)].

CONCLUSIONS

The significant decrease in nevirapine resistance conferred by 1 week of zidovudine + lamivudine should help policymakers optimize peripartum HIV prophylaxis recommendations.