Nevirapine resistance is common after single-dose nevirapine therapy to prevent mother-to-child transmission of HIV infection. A 7-day tail of highly active combination therapy or 1 month of dual therapy prevents most nevirapine resistance to minimal toxicity.

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 log10 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.

Background

Data on determinants of long-term disease progression in HIV-infected patients on antiretroviral therapy (ART) are limited in low and middle-income settings.

Methods

Effects of current CD4 count, viral load and haemoglobin and diagnosis of AIDS-defining events (ADEs) after start of combination ART (cART) on death and new ADEs were assessed using Poisson regression, in patient aged ≥18 years within a multi-centre cohort in Thailand.

Results

Among 1,572 patients, median follow-up from cART initiation was 4.4 (IQR 3.6–6.3) years. The analysis of death was based on 60 events during 6,573 person-years; 30/50 (60%) deaths with underlying cause ascertained were attributable to infections. Analysis of new ADE included 192 events during 5,865 person-years; TB and Pneumocystis jiroveci pneumonia were the most commonly presented first new ADE (35% and 20% of cases, respectively). In multivariable analyses, low current CD4 count after starting cART was the strongest predictor of death and of new ADE. Even at CD4 above 200 cells/mm3, survival improved steadily with CD4, with mortality rare at ≥500 cells/mm3 (rate 1.1 per 1,000 person-years). Haemoglobin had a strong independent effect, while viral load was weakly predictive with poorer prognosis only observed at ≥100,000 copies/ml. Mortality risk increased following diagnosis of ADEs during cART. The decline in mortality rate with duration on cART (from 21.3 per 1,000 person-years within first 6 months to 4.7 per 1,000 person-years at ≥36 months) was accounted for by current CD4 count.

Conclusions

Patients with low CD4 count or haemoglobin require more intensive diagnostic and treatment of underlying causes. Maintaining CD4≥500 cells/mm3 minimizes mortality. However, patient monitoring could potentially be relaxed at high CD4 count if resources are limited. Optimal ART monitoring strategies in low-income settings remain a research priority. Better understanding of the aetiology of anaemia in patients on ART could guide prevention and treatment.

Background

Approximately 4 million of people are co-infected with HIV and Hepatitis B virus (HBV). In resource-limited settings, the majority of HIV-infected patients initiate first-line highly active antiretroviral therapy containing lamivudine (3TC-containing-HAART) and long-term virological response of HBV to lamivudine-containing HAART in co-infected patients is not well known.

Methodology/Principal Finding

HIV-HBV co-infected patients enrolled in the PHPT cohort (ClinicalTrials.gov NCT00433030) and initiating a 3TC-containing-HAART regimen were included. HBV-DNA, HIV-RNA, CD4+ T-cell counts and alanine transaminase were measured at baseline, 3 months, 12 months and then every 6 months up to 5 years. Kaplan-Meier analysis was used to estimate the cumulative rates of patients who achieved and maintained HBV-DNA suppression. Of 30 co-infected patients, 19 were positive for HBe antigen (HBeAg). At initiation of 3TC-containing-HAART, median HBV DNA and HIV RNA levels were 7.35 log10 IU/mL and 4.47 log10 copies/mL, respectively. At 12 months, 67% of patients achieved HBV DNA suppression: 100% of HBeAg-negative patients and 47% of HBeAg-positive. Seventy-three percent of patients had HIV RNA below 50 copies/mL. The cumulative rates of maintained HBV-DNA suppression among the 23 patients who achieved HBV-DNA suppression were 91%, 87%, and 80% at 1, 2, and 4 years respectively. Of 17 patients who maintained HBV-DNA suppression while still on 3TC, 4 (24%) lost HBsAg and 7 of 8 (88%) HBeAg-positive patients lost HBeAg at their last visit (median duration, 59 months). HBV breakthrough was observed only in HBeAg-positive patients and 6 of 7 patients presenting HBV breakthrough had the rtM204I/V mutations associated with 3TC resistance along with rtL180M and/or rtV173L.

Conclusions

All HBeAg-negative patients and 63% of HBeAg-positive HIV-HBV co-infected patients achieved long-term HBV DNA suppression while on 3TC-containing-HAART. This study provides information useful for the management of co-infected patients in resource-limited countries where the vast majority of co-infected patients are currently receiving 3TC.

Background

Limited data exist for the efficacy of second-line antiretroviral therapy among children in resource limited settings. We assessed the virologic response to protease inhibitor-based ART after failing first-line non-nucleoside reverse transcriptase inhibitor (NNRTI)-based regimens.

Methods

A retrospective chart review was conducted at 8 Thai sites of children who switched to PI –based regimens due to failure of NNRTI –based regimens. Primary endpoints were HIV RNA < 400 copies/ml and CD4 change over 48 weeks.

Results

Data from 241 children with median baseline values before starting PI-based regimens of 9.1 years for age, 10% for CD4%, and 4.8 log10 copies/ml for HIV RNA were included; 104 (41%) received a single ritonavir-boosted PI (sbPI) with 2 NRTIs and 137 (59%) received double-boosted PI (dbPI) with/without NRTIs based on physician discretion. SbPI children had higher baseline CD4 (17% vs. 6%, p < 0.001), lower HIV RNA (4.5 vs. 4.9 log10 copies/ml, p < 0.001), and less frequent high grade multi-NRTI resistance (12.4% vs 60.5%, p < 0.001) than the dbPI children. At week 48, 81% had HIV RNA < 400 copies/ml (sbPI 83.1% vs. dbPI 79.8%, p = 0.61) with a median CD4 rise of 9% (+7%vs. + 10%, p < 0.005). However, only 63% had HIV RNA < 50 copies/ml, with better viral suppression seen in sbPI (76.6% vs. 51.4%, p 0.002).

Conclusion

Second-line PI therapy was effective for children failing first line NNRTI in a resource-limited setting. DbPI were used in patients with extensive drug resistance due to limited treatment options. Better access to antiretroviral drugs is needed.

Indinavir boosted with ritonavir (IDV/r) dosing with 400/100 mg, twice daily, is preferred in Thai adults, but this dose can lead to concentrations close to the boundaries of its therapeutic window. The objectives of this analysis were to validate a population pharmacokinetic model to describe IDV/r concentrations in HIV-infected Thai patients and to investigate the impact of patient characteristics on achieving adequate IDV concentrations. IDV/r concentration data from 513 plasma samples were available. Population means and variances of pharmacokinetic parameters were estimated using a non-linear mixed effects regression model (NONMEM Version VI). Monte Carlo simulations were performed to estimate the probability of achieving IDV concentrations within its therapeutic window. IDV/r pharmacokinetics was best described by a one compartment model coupled with a single transit compartment absorption model. Body weight influenced indinavir apparent oral clearance (CL/F) and volume of distribution (Vd/F) and allometric scaling significantly reduced the interindividual variability. Final population estimates (interindividual variability in percentage) of indinavir CL/F and Vd/F were 21.3 L/h/70kg (30%) and 90.7 L/70kg (22%), respectively. Based on model simulations, the probability of achieving an IDV trough concentration > 0.1 mg/L was >99% for 600/100 mg and >98% for 400/100 mg, twice daily, in patients 40–80 kg. However, the probability of achieving IDV concentrations associated with an increased risk of drug toxicity (>10.0 mg/L), increased from 1% to 10% with 600/100 mg, compared to <1% with 400/100 mg when body weight decreased from 80 to 40 kg. The validated model developed predicts that 400/100 mg of IDV/r, twice daily, provides indinavir concentrations within the recommended therapeutic window for the majority of patients. The risk of toxic drug concentrations increases rapidly with IDV/r dose of 600/100 mg for patients <50 kg and therapeutic drug monitoring of IDV concentrations would help to reduce the risk of IDV-induced nephrotoxicity.

Background. There are scarce data on the long-termsurvival of human immunodeficiency virus (HIV)—infected children receiving antiretroviral therapy (ART) in lower-middle income countries beyond 2 years of follow-up.

Methods. Previously untreated children who initiated ART on meeting immunological and/or clinical criteria were followed in a prospective cohort in Thailand. The probability of survival up to 5 years from initiation was estimated using Kaplan-Meier methods, and factors associated with mortality were assessed using Cox regression analyses.

Results. Five hundred seventy-eight children received ART; of these, 111 (19.2%) were followed since birth. At start of ART (baseline), the median age was 6.7 years, 128 children (22%) were aged <2 years, and the median CD4 cell percentage was 7%. Median duration of follow-up was 53 months; 42 children (7%) died, and 38 (7%) were lost to follow-up. Age <12 months, low CD4 cell percentage, and low weight-for-height z score at ART initiation were independently associated with mortality (P < .001). The probability of survival among infants aged <12 months at baseline was 84.3% at 1 year and 76.7% at 5 years of ART, compared with 95.7% and 94.8%, respectively, among children aged ⩾1 year. Low CD4 cell percentage and wasting at baseline had a strong association with mortality among older children but weak or no association among infants.

Conclusions. Children who initiated ART as infants after meeting immunological and/or clinical criteria had a high risk of mortality which persisted beyond the first year of therapy. Among older children, those with severe wasting or low CD4 cell percentage at treatment initiation were at high risk of mortality during the first 6 months of therapy. These findings support the scale-up of early HIV diagnosis and immediate treatment in infants, before advanced disease progression in older children.

Our objective was to analyze, in formula-fed infants, correlates of HIV mother-to-child transmission, including cytomegalovirus (CMV) infection.

HIV-infected infants were matched with HIV-uninfected by maternal HIV RNA in a case-control design. Infant CMV infection was determined by CMV-IgG at 18 months and timed by earlier CMV-IgM or -DNA. Correlations were assessed using logistic regression.

In utero HIV infection was independently associated with congenital CMV infection (P=0.01), intrapartum HIV infection with congenital-plus-intrapartum/neonatal CMV infection (P=0.01), and overall HIV with overall CMV infection (P=0.001), as well as prematurity (P=0.004).

Congenital and acquired CMV infections are strong independent correlates of mother-to-child HIV transmission.

Background

WHO recommends starting therapy with a non-nucleoside reverse transcriptase inhibitor (NNRTI) and two nucleoside reverse transcriptase inhibitors (NRTIs), i.e. nevirapine or efavirenz, with lamivudine or emtricitabine, plus zidovudine or tenofovir. Few studies have compared resistance patterns induced by efavirenz and nevirapine in patients infected with the CRF01_AE Southeast Asian HIV-subtype. We compared patterns of NNRTI- and NRTI-associated mutations in Thai adults failing first-line nevirapine- and efavirenz -based combinations, using Bayesian statistics to optimize use of data.

Methods and Findings

In a treatment cohort of HIV-infected adults on NNRTI-based regimens, 119 experienced virologic failure (>500 copies/mL), with resistance mutations detected by consensus sequencing. Mutations were analyzed in relation to demographic, clinical, and laboratory variables at time of genotyping. The Geno2Pheno system was used to evaluate second-line drug options. Eighty-nine subjects were on nevirapine and 30 on efavirenz. The NRTI backbone consisted of lamivudine or emtricitabine plus either zidovudine (37), stavudine (65), or tenofovir (19). The K103N mutation was detected in 83% of patients on efavirenz vs. 28% on nevirapine, whereas Y181C was detected in 56% on nevirapine vs. 20% efavirenz. M184V was more common with nevirapine (87%) than efavirenz (63%). Nevirapine favored TAM-2 resistance pathways whereas efavirenz selected both TAM-2 and TAM-1 pathways. Emergence of TAM-2 mutations increased with the duration of virologic replication (OR 1.25–1.87 per month increment). In zidovudine-containing regimens, the overall risk of resistance across all drugs was lower with nevirapine than with efavirenz, whereas in tenofovir-containing regimen the opposite was true.

Conclusions

TAM-2 was the major NRTI resistance pathway for CRF01_AE, particularly with nevirapine; it appeared late after virological failure. In patients who failed, there appeared to be more second-line drug options when zidovudine was combined with nevirapine or tenofovir with efavirenz than with alternative combinations.

Abstract

The evolution of hematological parameters in HIV-1-exposed uninfected infants according to various durations of perinatal zidovudine exposure was studied. We used data prospectively collected among 1122 HIV-uninfected formula-fed infants born to HIV-infected mothers who participated in a clinical trial to prevent perinatal transmission in Thailand (PHPT-1). Infants were exposed to different durations of zidovudine both in utero and after birth. Hemoglobin level and leukocyte, absolute neutrophil, and lymphocyte counts were measured at birth and at 6 weeks of age. The association between hematological parameters at birth and the duration of zidovudine exposure in utero was studied using a linear regression model, and changes between birth and 6 weeks of age and the duration of postnatal zidovudine exposure using mixed effects models. At birth, the hemoglobin level was lower in newborns exposed to zidovudine for more than 7.5 weeks in utero (adjusted regression coefficient: −0.6 g/dl; 95% confidence interval: −1.1 to −0.1). Six weeks after birth, the hemoglobin level had decreased faster in infants administered zidovudine for more than 4 weeks (adjusted regression coefficient: −0.1 g/dl; 95% confidence interval: −0.2 to −0.1). The duration of perinatal zidovudine exposure was not associated with the evolution of leukocyte, neutrophil, and lymphocyte counts. Despite the differences in hemoglobin levels, grade 3 or 4 anemia did not significantly differ by maternal or infant zidovudine duration. The clinical impact appeared modest, but longer exposure may warrant close monitoring.

Objective

To evaluate the pharmacokinetics and HIV viral load (VL) response following initiation during the third trimester of pregnancy of zidovudine (ZDV) plus standard dose lopinavir boosted with ritonavir (LPV/r), twice daily, until delivery for the prevention of mother-to-child transmission of HIV (PMTCT).

Design

Prospective study nested within a multicenter, three arm, randomised, phase III PMTCT trial in Thailand (PHPT-5, ClinicalTrials.gov Identifier: NCT00409591).

Methods

Women randomized to receive 300 mg ZDV and 400/100 mg LPV/r twice daily from 28 weeks’ gestation, or as soon as possible thereafter, until delivery had intensive steady-state 12-hour blood sampling performed. LPV/r pharmacokinetic parameters were calculated using non-compartmental analysis. Rules were defined a priori for a LPV/r dose escalation based on the proportion of women with an LPV AUC < 52 mcg.hr/mL (10th percentile for LPV AUC in non-pregnant adults). HIV-1 RNA response was assessed during the third trimester.

Results

Thirty-eight women were evaluable; at entry median (range) gestational age was 29 weeks (28–36), weight 59.5 kg (45.0–91.6), CD4 cell count 442 cells/mm3 (260–1327) and HIV-1 RNA viral load 7,818 copies/mL (<40–402,015). Geometric mean (90% confidence interval) LPV AUC, Cmax and Cmin were 64.6 mcg.hr/mL (59.7–69.8), 8.1 mcg/mL, (7.5–8.7) and 2.7 mcg/ml (2.4–3.0), respectively. 31 of 38 (81%) women had an LPV AUC above the AUC target. All women had a HIV-1 viral load less than 400 copies/mL at the time of delivery.

Conclusion

A short course of ZDV plus standard dose LPV/r initiated during the 3rd trimester of pregnancy achieved adequate LPV exposure and virologic response.

Summary

Objectives

The objectives of this study were to assess the prevalence and factors associated with hepatitis C virus (HCV) infection in human immunodeficiency virus (HIV)-infected and -uninfected Thai pregnant women and the rate of HCV transmission to their infants.

Patients and methods

Study subjects included 1435 HIV-infected pregnant women and their infants, enrolled in a perinatal HIV prevention trial, and a control group of 448 HIV-uninfected pregnant women. Women were screened for HCV antibodies with an enzyme immunoassay. Positive results were confirmed by recombinant immunoblot and HCV RNA quantification. Infants were tested for HCV antibodies at 18 months or for HCV RNA at between 6 weeks and 6 months.

Results

Of the HIV-infected women, 2.9% were HCV-infected compared to 0.5% of HIV-uninfected women (p = 0.001). Only history of intravenous drug use was associated with HCV infection in HIV-infected women. Ten percent of infants born to co-infected mothers acquired HCV. The risk of transmission was associated with a high maternal HCV RNA (p = 0.012), but not with HIV-1 load or CD4 count.

Conclusions

Acquisition of HCV through intravenous drug use partially explains the higher rate of HCV infection in HIV-infected Thai women than in HIV-uninfected controls. Perinatal transmission occurred in 10% of infants of HIV–HCV-co-infected mothers and was associated with high maternal HCV RNA.

Background

In resource-limited settings, most perinatally HIV-1-infected infants do not receive timely antiretroviral therapy because early HIV-1 diagnosis is not available or affordable.

Objective

To assess the performance of a low cost in-house real-time PCR assay to detect HIV-1 DNA in infant dried blood spots (DBS).

Methods

1319 DBS collected throughout Thailand from non-breastfed infants born to HIV-1-infected mothers were shipped at room temperature to a central laboratory. In-house real-time DNA-PCR results were compared to Roche Amplicor® HIV-1 DNA test (Version 1.5) results. In addition, we verified the Roche test performance on DBS sampled from 1218 other infants using as reference HIV serology result at 18 months of age.

Results

Real-time DNA-PCR and Roche DNA-PCR results were 100% concordant. Compared to HIV-serology results, the Roche test sensitivity was 98.6% (95% CI: 92.6 to 100.0%) and its specificity at 4 months of age was 99.7% (95% CI: 99.2 to 99.9%).

Conclusions

In-house real-time PCR performed as well as the Roche test in detecting HIV-1 DNA on DBS in Thailand. Combined use of DBS and real-time PCR assays is a reliable and affordable tool to expand access to early HIV-1 diagnosis in remote and resource-limited settings, enabling timely treatment for HIV-1-infected infants.

Background

Antiretroviral therapy (ART) has become more available throughout the developing world during the past five years. The World Health Organization recommends nonnucleoside reverse transcriptase inhibitor-based regimens as initial ART. However, their efficacy may be compromised by resistance mutations selected by single-dose nevirapine (sdNVP) used to prevent mother-to-child-transmission of HIV-1 (PMTCT). There is no simple and efficient method to detect such mutations at initiation of ART.

Methods

181 women participating in a PMTCT clinical trial who started NVP-ART after they had received sdNVP or placebo were tested for nevirapine-resistance point-mutations (K103N, Y181C, and G190A) using 100 copies of HIV-1 DNA with a sensitive oligonucleotide ligation assay (OLA) able to detect mutants at low concentrations (≥5% of the viral population). Virologic failure was defined as plasma HIV-1 RNA confirmed >50 copies/mL between 6–18 months of NVP-ART.

Results

At initiation of NVP-ART, resistance mutations were identified in 26% of 148 participants given sdNVP (K103N-13%, Y181C-5%, G190A-19%; ≥2 mutations-10%) at a median 9.3 months after sdNVP. The risk of virologic failure was .62 (95% confidence interval (CI), 0.46–0.77) in women with ≥1 resistance mutation, compared to 0.25 (95% CI, 0.17–0.35) in those without detectable resistance mutations (P<.0001). Failure was independently associated with resistance, an interval of <6 months between sdNVP and NVP-ART initiation, and a viral load above the median at NVP-ART initiation.

Conclusions

Access to simple and inexpensive assays to detect low-concentrations of NVP-resistant HIV-1 DNA prior to the initiation of ART could help improve the outcome of first-line antiretroviral therapy.

Background

Intrapartum single-dose-nevirapine along with third trimester maternal and infant zidovudine are essential components of programs to prevent mother-to-child HIV transmission in resource-limited settings. The persistence of nevirapine in the plasma for three weeks postpartum risks selection of resistance mutations to non-nucleoside reverse transcriptase inhibitors (NNRTI). We hypothesized that a one-month zidovudine-plus-didanosine course initiated at the same time as single-dose nevirapine would prevent the selection of nevirapine resistance mutations.

Methods

PHPT-4 HIV-infected pregnant women with CD4 counts above 250 cells/mm3 received antepartum zidovudine from the third trimester until delivery, single-dose nevirapine during labor and one-month zidovudine-plus-didanosine postpartum. These women were matched on baseline viral load (VL), CD4 count and duration of antepartum zidovudine to women who received single-dose nevirapine in the PHPT-2 trial (controls). Consensus sequencing and the more sensitive oligonucleotide ligation assay (OLA) were performed on samples drawn at 7–10, 37–45 and 120 days postpartum (if VL>500 copies/mL) to detect K103N/Y181C/G190A mutations.

Results

The 222 PHPT-4 subjects did not differ from their matched controls in baseline characteristics except for age. Combined groups median CD4 count was 421 cells/mm3 [IQR: 322–549], VL 3.45 log10 copies/mL [2.79–4.00] and ZDV prophylaxis 10.4 weeks [9.1–11.4]. Using consensus sequencing, major NNRTI resistance mutations were detected postpartum in 0% of PHPT-4 subjects versus 10.4% of PHPT-2 controls. OLA detected resistance in 1.8% of PHPT-4 subjects versus 18.9% controls. Major NNRTI resistance mutations were detected by either method in 1.8% of PHPT-4 subjects versus 20.7% in controls (p<10−10).

Conclusions

One-month postpartum zidovudine-plus-didanosine prevented the selection of vast majority NNRTI resistance mutations.

Objectives

To investigate the association of single nucleotide polymorphisms (SNPs) with nevirapine concentrations following intra-partum single-dose nevirapine.

Methods

Plasma and DNA samples were obtained from 330 HIV-infected Thai women who received intra-partum single-dose nevirapine in the PHPT-2 clinical trial to prevent perinatal HIV transmission. Nine SNPs within CYP2B6, CYP3A4 and ABCB1 were genotyped by real-time PCR. Nevirapine plasma concentrations were determined by HPLC and used in a population pharmacokinetic analysis.

Results

Higher nevirapine exposure was observed in women carrying the CYP2B6 516G>T polymorphism, but this did not reach statistical significance (P = 0.054). The TGATC CYP2B6 haplotype (g.3003T, 516G, 785A, g.18492T and g.21563C) was associated with increased nevirapine clearance and lower exposure (P = 0.0029). The median time for nevirapine concentrations to reach 10 ng/mL post-partum (nevirapine IC50 for HIV-1) was 14 days [interquartile range (IQR, 14–18)] for TGATC homozygotes, 16 days (14–20) for TGATC heterozygotes and 18 days (14–20) for non-TGATC homozygotes (P = 0.020).

Conclusions

The CYP2B6 516G>T impact on nevirapine concentrations was less pronounced after intra-partum single-dose nevirapine than reported under steady-state conditions, perhaps due to lack of enzyme auto-induction at the time of dosing. Although the TGATC CYP2B6 haplotype may shorten the persistence of nevirapine post-partum, its practical implications for the prevention of HIV transmission or selection of resistance mutations are likely limited.

A single dose of nevirapine (sdNVP) to prevent mother-to-child transmission of HIV-1 increases the risk of failure of subsequent NVP-containing antiretroviral therapy (ART), especially when initiated within 6 months of sdNVP administration, emphasizing the importance of understanding the decay of nevirapine-resistant mutants. Nevirapine-resistant HIV-1 genotypes (with the mutations K103N, Y181C, and/or G190A) from 21 women were evaluated 10 days and 6 weeks after sdNVP administration and at the initiation of ART. Resistance was assayed by consensus sequencing and by a more sensitive assay (oligonucleotide ligation assay [OLA]) using plasma-derived HIV-1 RNA and cell-associated HIV-1 DNA. OLA detected nevirapine resistance in more specimens than consensus sequencing did (63% versus 33%, P < 0.01). When resistance was detected only by OLA (n = 45), the median mutant concentration was 18%, compared to 61% when detected by both sequencing and OLA (n = 51) (P < 0.0001). The proportion of women whose nevirapine resistance was detected by OLA 10 days after sdNVP administration was higher when we tested their HIV-1 RNA (95%) than when we tested their HIV-1 DNA (88%), whereas at 6 weeks after sdNVP therapy, the proportion was greater with DNA (85%) than with RNA (67%) and remained higher with DNA (33%) than with RNA (11%) at the initiation of antiretroviral treatment (median, 45 weeks after sdNVP therapy). Fourteen women started NVP-ART more than 6 months after sdNVP therapy; resistance was detected by OLA in 14% of the women but only in their DNA. HIV-1 resistance to NVP following sdNVP therapy persists longer in cellular DNA than in plasma RNA, as determined by a sensitive assay using sufficient copies of virus, suggesting that DNA may be superior to RNA for detecting resistance at the initiation of ART.

Lopinavir (LPV) exposure is reduced during the third trimester of pregnancy. We report the pharmacokinetics of standard LPV-ritonavir dosing (400/100 mg twice daily) in the immediate and early postpartum period when initiated during labor. In 16 human immunodeficiency virus-infected Thai women, the median (range) LPV area under the concentration-time curve and maximum and minimum concentrations in plasma were 99.7 (66.1 to 180.5) μg·h/ml, 11.2 (8.0 to 17.5) μg/ml, and 4.6 (1.7 to 12.5) μg/ml, respectively, at 41 (12 to 74) h after delivery. All of the women attained adequate LPV levels through 30 days postpartum. No serious adverse events were reported.

Objectives:

To respond to the primary safety objective of the Perinatal HIV Prevention Trial 1 (PHPT-1) by studying the evolution of haematological parameters according to zidovudine exposure duration in HIV-1−infected pregnant women.

Design:

Multicenter, randomized, double-blind, controlled trial of different durations of zidovudine prophylaxis.

Setting:

27 hospitals in Thailand.

Participants:

1,436 HIV-infected pregnant women in PHPT-1.

Intervention:

Zidovudine prophylaxis initiation at 28 or 35 wk gestation.

Outcome measures:

Haemoglobin level, leucocytes, total lymphocyte counts, and absolute neutrophil counts were measured at 26, 32, and 35 wk and at delivery. The evolution of haematological parameters was estimated between 26 and 35 wk (zidovudine/placebo) and between 35 wk and delivery to compare a long versus short zidovudine exposure. For each parameter, linear mixed models were adjusted on baseline sociodemographic variables, HIV clinical stage, CD4 count, and viral load.

Results:

Between 26 and 35 wk, haemoglobin, leucocytes, and absolute neutrophil counts decreased in zidovudine-exposed compared to unexposed women (mean difference [95% CI] −0.4 [−0.5 to −0.3], −423 [−703 to −142], −485 [−757 to −213], respectively). However, between 35 wk and delivery, the haematological parameters increased faster in women exposed to long rather than short durations of zidovudine (0.1 [0.0 to 0.1]; 105 [18 to 191]; 147 [59 to 234], respectively). At delivery, the differences were not statistically significant, except for mean haemoglobin level, which remained slightly lower in the long zidovudine treatment group (difference: 0.2 g/dl). Zidovudine had no negative impact on the absolute lymphocyte counts.

Conclusion:

Zidovudine initiated at 28 wk gestation rather than 35 wk had a transient negative impact on the evolution of haematological parameters, which was largely reversed by delivery despite continuation of zidovudine. This result provides reassurance about the safety of early initiation of zidovudine prophylaxis during pregnancy to maximize prevention of perinatal HIV.

Editorial Commentary

Background: Pregnant women who are infected with HIV are at high risk of passing on the virus to their unborn baby during pregnancy, labour, and breastfeeding. Around 15%–30% of babies born to HIV-positive women will themselves become infected, if the woman avoids breast-feeding but does not use any other means of preventing the virus from being passed on. However, if a drug, zidovudine (AZT), is given during pregnancy the chance of HIV being passed on to a baby drops from around 23% to around 8%. In some settings it may not be realistic to give the standard course of zidovudine, from 28 weeks of pregnancy, because of its cost and complexity. A number of trials have therefore looked at whether standard-course and short-course zidovudine are equivalent at reducing the risk of passing on HIV from mother to baby. One trial, the Perinatal HIV Prevention Trial-1 (PHPT-1) found that the short treatment course was substantially less effective at preventing HIV from being passed on from mother to baby. Current international guidance therefore recommends starting zidovudine at 28 weeks of pregnancy. However, zidovudine does have several side effects, including anemia; it can also cause a drop in the levels of certain types of white blood cell, and is thought to be toxic to bone marrow. The researchers who had carried out the PHPT-1 trial therefore wanted to do a subsequent analysis of data from that trial to find out whether there were any differences in these safety outcomes between standard and short course zidovudine.

What the trial shows: In total 1,436 women were recruited into the trial and assigned to receive either zidovudine from 28 weeks of pregnancy until delivery (standard course; 769 women), or from 35 weeks to delivery (short course; 667). Blood tests were performed at 26, 32, and 35 weeks of pregnancy and then at delivery, and the main outcomes assessed in this secondary analysis were the hemoglobin levels (to check for anemia), and levels of white blood cells, including the levels of two particular types (neutrophils and lymphocytes). The researchers found that standard-course zidovudine resulted in a drop at 35 weeks in the levels of hemoglobin and white blood cells, relative to short-course zidovudine. However, by the time of delivery these levels had recovered and no significant differences could be observed between the two arms of the trial. Women receiving standard-course zidovudine were more likely to experience severe anemia, which although a rare event in both arms of the trial, could have serious outcomes.

Strengths and limitations: The original trial from which these data were collected was a relatively large, randomized study and in which there was a low rate of loss to follow up. Although no formal sample size calculation was performed for the analyses presented here, the study probably had sufficient power to detect small differences in the outcomes assessed. A key limitation of this study is that the analyses presented here are a secondary exploration of data from the PHPT-1 trial and should therefore be seen as hypotheses to test in further studies, rather than as definitive conclusions.

Contribution to the evidence: The analyses presented here add to the findings of the parent trial, PHPT-1, by providing additional data about the toxicity of zidovudine. Other trials have not clearly established whether there are differences between short- and standard-course zidovudine in terms of their toxicity. The findings support current guidelines recommending standard-course zidovudine therapy for HIV-positive pregnant women. It is also crucial that efforts are made to ensure women worldwide can get access to facilities for monitoring the status of their HIV infection, and then receive highly active antiretroviral therapy when it is needed.