Regimens In Resource-limited Settings Research Articles

Evaluation of Circulating and Archived HIV-1 Integrase Drug-Resistance Variants among Patients on Third-Line ART in Cameroon: Implications for Dolutegravir-Containing Regimens in Resource-Limited Settings.

To ensure the long-term efficacy of dolutegravir (DTG), we evaluated the genotypic profile in viral reservoirs among patients on third-line (3L) antiretroviral therapy (ART) in Cameroon, according to prior exposure to raltegravir (RAL). A facility-based study was conducted from May through December 2021 among patients on 3L ART from HIV treatment centers in Yaoundé and Douala. Viral load was measured, and genotyping was performed on plasma RNA and proviral DNA. HIV-1 drug resistance mutations were interpreted using HIVdb.v9.1 and phylogeny analysis was performed using MEGA.v7, with P < 0.05 considered significant. Of the 12,093 patients on ART, 53 fully met our inclusion criteria. The median (IQR) age was 51 years (40 to 55 years), and the male/female ratio was 4/5. The median duration on integrase strand-transfer inhibitors (INSTI)-containing regimens was 18 months (12 to 32 months), and 15.09% (8/53) were exposed to RAL. The most administered 3L ART was TDF+3TC+DTG+DRV/r (33.96%, 18/53). Only 5.66% (3/53) had unsuppressed viremia (>1000 copies/mL). Resistance testing in proviral DNA was successful for 18/22 participants and revealed 1/18 patients (5.56%, in the RAL-arm) with archived mutations at major resistance positions (G140R and G163R). Five subtypes were identified, CRF02_AG (12/18), CRF22_01AE (3/18), A1 (1/18), G (1/18), and F2 (1/18). In Cameroon, 3L-experienced patients had a good virological response with a low level of archived mutations in the integrase. This finding underscored the use of DTG-containing ART for heavily treated patients in similar programmatic settings. However, patients with prior exposure to RAL should be closely monitored following a stratified or personalized approach to mitigate risks of INSTI-resistance, alongside pharmacovigilance. IMPORTANCE We described the analysis of the genotypes of the population within third-line antiviral therapy in Cameroon, with a focus on defining the effects of prior raltegravir (RAL) treatment and resistance mutations for current dolutegravir (DTG) treatment. While supporting the current transition to DTG-containing ART in resource-limited settings toward the achievement of the UNAIDS' goal of HIV elimination by 2030, our findings suggested that RAL-exposed patients may need a specific monitoring approach either in a stratified or personalized model of third-line ART to ensure the long-term success of DTG-containing regimens.

Baseline integrase drug resistance mutations and conserved regions across HIV-1 clades in Cameroon: implications for transition to dolutegravir in resource-limited settings.

Transition to dolutegravir-based regimens in resource-limited settings (RLS) requires prior understanding of HIV-1 integrase variants and conserved regions. Therefore, we evaluated integrase drug resistance mutations (DRMs) and conserved regions amongst integrase strand transfer inhibitor (INSTI)-naive patients harbouring diverse HIV-1 clades in Cameroon. A cross-sectional study was conducted amongst 918 INSTI-naive patients from Cameroon (89 ART-naive and 829 ART-experienced patients). HIV-1 sequences were interpreted regarding INSTI-DRMs using the Stanford HIVdb v8.9-1 and the 2019 IAS-USA list. Amino acid positions with <1% variability were considered as highly conserved. Subtyping was performed by phylogeny. Overall prevalence (95% CI) of INSTI-DRMs was 0.8% (0.4-1.7), with 0.0% (0.0-4.0) amongst ART-naive versus 0.9% (0.5-1.9) amongst ART-experienced patients; P = 0.44. Accessory mutations (95% CI) were found in 33.8% (30.9-37.0), with 38.2% (28.1-49.1) amongst ART-naive versus 33.4% (30.4-36.7) amongst ART-experienced patients; P = 0.21. Of 288 HIV-1 integrase amino acid positions, 58.3% were highly conserved across subtypes in the following major regions: V75-G82, E85-P90, H114-G118, K127-W132, E138-G149, Q168-L172, T174-V180, W235-A239 and L241-D253. Wide genetic diversity was found (37 clades), including groups M (92.3%), N (1.4%), O (6.2%) and P (0.1%). Amongst group M, CRF02_AG was predominant (47.4%), with a significantly higher frequency (95% CI) of accessory mutations compared with non-AG [41.4% (36.8-46.0) versus 27.1% (23.3-31.2) respectively; P < 0.001]. The low baseline of INSTI-DRMs (<1%) in Cameroon suggests effectiveness of dolutegravir-based regimens. In spite of high conservation across clades, the variability of accessory mutations between major circulating strains underscores the need for monitoring the selection of INSTI-DRMs while scaling up dolutegravir-based regimens in RLS.

Dose Rationale for Amoxicillin in Neonatal Sepsis When Referral Is Not Possible.

BackgroundDespite the widespread use of amoxicillin in young children, efforts to establish the feasibility of simplified dosing regimens in resource-limited settings have relied upon empirical evidence of efficacy. Given the antibacterial profile of beta-lactams, understanding of the determinants of pharmacokinetic variability may provide a more robust guidance for the selection of a suitable regimen. Here we propose a simplified dosing regimen based on pharmacokinetic-pharmacodynamic principles, taking into account the impact of growth, renal maturation and disease processes on the systemic exposure to amoxicillin.Materials and MethodsA meta-analytical modeling approach was applied to allow the adaptation of an existing pharmacokinetic model for amoxicillin in critically ill adults. Model parameterization was based on allometric concepts, including a maturation function. Clinical trial simulations were then performed to characterize exposure, as defined by secondary pharmacokinetic parameters (AUC, Cmax, Cmin) and T>MIC. The maximization of the T>MIC was used as criterion for the purpose of this analysis and results compared to current WHO guidelines.ResultsA two-compartment model with first order absorption and elimination was found to best describe the pharmacokinetics of amoxicillin in the target population. In addition to the changes in clearance and volume distribution associated with demographic covariates, our results show that sepsis alters drug distribution, leading to lower amoxicillin levels and longer half-life as compared to non-systemic disease conditions. In contrast to the current WHO guidelines, our analysis reveals that amoxicillin can be used as a fixed dose regimen including two weight bands: 125 mg b.i.d. for patients with body weight < 4.0 kg and 250 mg b.i.d. for patients with body weight ≥ 4.0 kg.ConclusionsIn addition to the effect of developmental growth and renal maturation, sepsis also alters drug disposition. The use of a model-based approach enabled the integration of these factors when defining the dose rationale for amoxicillin. A simplified weight-banded dosing regimen should be considered for neonates and young infants with sepsis when referral is not possible.

Calcaneal Quantitative Ultrasonography and Urinary Retinol-Binding Protein in Antiretroviral-Treated Patients With Human Immunodeficiency Virus in Uganda: A Pilot Study.

Data on bone health and renal impairment in people with human immunodeficiency virus (HIV) in resource-limited settings are limited. The primary aim of this study was to investigate the potential role of calcaneal quantitative ultrasonography (QUS) in predicting bone mineral density (BMD) reduction in a population of Ugandan HIV-infected individuals receiving long-term antiretroviral therapy; the secondary end point was to assess the prevalence of proximal tubular dysfunction and the correlation between elevated urinary retinol-binding protein-urinary creatinine ratio (uRBP/uCr) and reduced BMD. We conducted a cross-sectional study at the Infectious Diseases Institute, Kampala, Uganda. We included 101 HIV-infected adults who had been receiving continuous antiretroviral therapy for ≥10 years and had undergone dual-energy x-ray absorptiometry (DXA) during the previous 12 months. All patients underwent calcaneal QUS evaluation and urine sample collection. DXA BMD measurements were significantly associated (P < .01) with calcaneal speed of sound, broadband ultrasound attenuation, and QUS index. Forty-seven individuals (47%) had abnormal uRBP/uCr values. A significant inverse correlation was observed between uRBP/uCr and DXA T scores (lumbar [P = .03], femoral neck [P < .001], and total hip [P = .002]). Calcaneal QUS results showed a moderate correlation with DXA outputs. The identified high prevalence of subclinical tubular impairment also highlights the importance of expanding access to tenofovir disoproxil fumarate-sparing regimens in resource-limited settings.

HIV-1 drug resistance testing is essential for heavily-treated patients switching from first- to second-line regimens in resource-limited settings: evidence from routine clinical practice in Cameroon

BackgroundWith the phase-out of stavudine (d4T), change to first-line regimens with zidovudine (AZT) or tenofovir (TDF) in resource-limited settings (RLS) might increase risks of cross-resistance to nucleos(t) ide reverse transcriptase inhibitors (NRTI). This would restrict the scope of switching to the World Health Organisation (WHO)-recommended standard second-line combinations (SLC) without HIV drug resistance (HIVDR)-testing in routine clinical practice.MethodsAn observational study was conducted among 101 Cameroonian patients (55.4% male, median [IQR] age 34 [10–41] years) failing first-line antiretroviral therapy (ART) in 2016, and stratified into three groups according to NRTIs exposure: exposure to both thymidine analogues AZT “and” D4T (group-A, n = 55); exposure to both TDF and AZT “or” D4T (group-B, n = 22); exposure solely to D4T (group-C, n = 24). Protease-reverse transcriptase HIVDR was interpreted using the HIVdb penalty scores (≥60: high-resistance; 20–59: intermediate-resistance; < 20: susceptible). The acceptable threshold for potential-efficacy was set at 80%.ResultsThe median [IQR] CD4, viral RNA, and time on ART, were respectively 129 [29–466] cells/μl, 71,630 [19,041-368,000] copies/ml, and 4 [2–5] years. Overall HIVDR-level was 89.11% (90/101), with 83.2% harbouring M184 V (high-level 3TC/FTC-resistance) and only 1.98% (2/101) major HIVDR-mutations to ritonavir-boosted protease-inhibitors (PI/r). Thymidine-analogue mutations (TAMs)-1 [T215FY (46.53%), M41 L (22.77%), L210 W (8.91%)], with cross-resistance to AZT and TDF, were higher compared to TAMs-2 [D67N (21.78%), K70R (19.80%), K219QE (18.81%)]. As expected, K65R was related with TDF-exposure: 0% (0/55) in group-A, 22.72% (5/22) group-B, 4.17% (1/24) group-C (p = 0.0013). The potential-efficacy of AZT vs. TDF was respectively 43.64% (24/55) vs. 70.91% (39/55) in group-A (p = 0.0038); 63.64% (14/22) vs. 68.28% (15/22) in group-B (p = 1.0000); and 37.50% (9/24) vs. 83.33% (20/24) in group-C (p = 0.0032). CRF02_AG was the prevailing subtype (63.40%), followed by CRF11.cpx (8.91%), A1 (7.92%), G (5.94%); without any significant effect of the subtype-distribution on HIVDR (92.2% in CRF02_AG vs. 83.8% in non-AG; p = 0.204).ConclusionFirst-line ART-failure exhibits high-level NRTI-resistance, with potential lower-efficacy of AZT compared to TDF. Significantly, using our 80% efficacy-threshold, only patients without NRTI-substitution on first-line could effectively switch to SLC following the WHO-approach. Patients with multiple NRTI-substitutions (exposed to both thymidine-analogues and TDF) on first-line ART would require HIVDR-testing to select active NRTIs for SLC.

Anemia in people on second line antiretroviral treatment in Lilongwe, Malawi: a cross-sectional study

BackgroundAnemia is common among people living with HIV infection and is frequently associated with poor quality of life and poor prognosis. It has been well described in antiretroviral naïve individuals and those on non-nucleoside reverse transcriptase inhibitor-based first line antiretroviral therapy (ART) regimens. However there is limited information on anemia for ART experienced individuals on protease inhibitor-based second line ART regimens in resource limited settings. Our objective was to describe the prevalence and risk factors of anemia in this ART experienced population in Malawi.MethodsWe conducted a cross-sectional study using routine facility data at two HIV clinics in Lilongwe, Malawi. The analysis included individuals receiving protease inhibitor-based second line ART. Clinical and laboratory data were collected at routine clinic visits. We used descriptive statistics, two-sample t-tests and multivariate logistic regression for data analysis.ResultsThree hundred seventy-seven records were included in this analysis (37% male, median age 41 years, median CD4 count 415 cells/μL). The prevalence of anemia was 125/377 (33.2%) − mild, moderate and severe anemia was 17.5%, 13.8%, and 1.9% respectively. Female participants had a higher prevalence than male participants (43.6% vs. 15.7%, p < 0.001). In multivariate logistic regression, female sex (adjusted odds ratio (aOR) 5.3; 95% CI 2.9–9.5) and a CD4 count <200 cell/ul (aOR 3.1; 95%CI 1.6–6.0) were associated with increased risk of having anemia while a BMI ≥30 kg/m2 (aOR 0.8; 95% CI 0.6–1.0) and being on ART for more than 10 years (aOR 0.4; 95% CI 0.2–0.9) were associated with reduced risk of anemia. Being on a zidovudine- containing ART regimen was not associated with anemia.ConclusionAnemia is common in people on second line ART in Lilongwe, Malawi. Screening for anemia in this population would be a useful strategy; especially for female patients, those who are underweight and have a low CD4 cell counts.

Prevalence of Antiretroviral Drug Resistance in Patients Who Are Not Responding to Protease Inhibitor-Based Treatment: Results From the First National Survey in South Africa.

Limited data exist on human immunodeficiency virus type 1 (HIV-1) resistance in patients who are not responding to protease inhibitor (PI)-based regimens in resource-limited settings. This study assessed resistance profiles in adults across South Africa who were not responding to PI-based regimens. pol sequencing was undertaken and submitted to the Stanford HIV Drug Resistance Database. At least 1 major PI mutation was detected in 16.4% of 350 participants. A total of 53.4% showed intermediate resistance to darunavir/ritonavir, whereas high-level resistance was not observed. Only 5.2% and 32.8% of participants showed high-level and intermediate resistance to etravirine, respectively. Although the prevalence of major PI mutations was within previously reported ranges, most patients will likely experience virological suppression during receipt of currently available South African third-line regimens.

High level of virological suppression among HIV-infected adults receiving combination antiretroviral therapy in Addis Ababa, Ethiopia.

Plasma viral load (pVL) is a key indicator of therapeutic response in HIV-infected patients receiving combination antiretroviral therapy (cART), but is often unavailable in routine clinical care in resource-limited settings. Previous model-based simulation studies have suggested that the benefits of routine pVL monitoring among patients on first-line regimens in resource-limited settings are modest, but this needs corroboration in well-defined study populations. We investigated virological suppression levels and identified predictors of detectable viraemia among 870 randomly selected patients who started cART between May 2009 and April 2012 in 10 health-care facilities in Addis Ababa, Ethiopia. A total of 656 (75.4%) patients, who were alive, were retained in HIV care and receiving cART for at least 6 months provided a blood sample for pVL measurement. Predictors of detectable viraemia were identified in a multivariate logistic regression model. In on-treatment analysis, 94.5% (95% CI 92.5, 96.1) of the patients achieved virological suppression below 400 copies/ml after a median (IQR) of 26 (17-35) months on cART. When patients who were lost to follow-up, dead or stopped were assumed to have had detectable viraemia, the proportion of patients with virological suppression <400 copies/ml decreased to 74.6% (95% CI 71.5%, 77.4%). Younger age, lower educational status, <95% medication adherence, lower CD4(+) T-cell count at cART initiation and/or the diagnosis of immunological failure thereafter significantly predicted detectable viraemia. Virological suppression levels can be high in an established ART programme in a resource-limited setting, even without the availability of routine pVL monitoring. Efforts to improve treatment outcomes should focus on younger and illiterate patients, earlier detection of HIV-positive status and cART initiation before patients are severely immunocompromised, and improving retention in care.

Incidence and Predictors of First Line Antiretroviral Regimen Modification in Western Kenya

BackgroundLimited antiretroviral treatment regimens in resource-limited settings require long-term sustainability of patients on the few available options. We evaluated the incidence and predictors of combined antiretroviral treatment (cART) modifications, in an outpatient cohort of 955 patients who initiated cART between January 2009 and January 2011 in western Kenya.MethodscART modification was defined as either first time single drug substitution or switch. Incidence rates were determined by Poisson regression and risk factor analysis assessed using multivariate Cox regression modeling.ResultsOver a median follow-up period of 10.7 months, 178 (18.7%) patients modified regimens (incidence rate (IR); 18.6 per 100 person years [95% CI: 16.2–21.8]). Toxicity was the most common cited reason (66.3%). In adjusted multivariate Cox piecewise regression model, WHO disease stage III/IV (aHR; 1.82, 95%CI: 1.25–2.66), stavudine (d4T) use (aHR; 2.21 95%CI: 1.49–3.30) and increase in age (aHR; 1.02, 95%CI: 1.0–1.04) were associated with increased risk of treatment modification within the first year post-cART. Zidovudine (AZT) and tenofovir (TDF) use had a reduced risk for modification (aHR; 0.60 95%CI: 0.38–0.96 and aHR; 0.51 95%CI: 0.29–0.91 respectively). Beyond one year of treatment, d4T use (aHR; 2.75, 95% CI: 1.25–6.05), baseline CD4 counts ≤350 cells/mm3 (aHR; 2.45, 95%CI: 1.14–5.26), increase in age (aHR; 1.05 95%CI: 1.02–1.07) and high baseline weight >60kg aHR; 2.69 95% CI: 1.58–4.59) were associated with risk of cART modification.ConclusionsEarly treatment initiation at higher CD4 counts and avoiding d4T use may reduce treatment modification and subsequently improve sustainability of patients on the available limited options.

Determinants of Mortality among Adult HIV-Infected Patients on Antiretroviral Therapy in a Rural Hospital in Southeastern Nigeria: A 5-Year Cohort Study.

Background. Study examined the determinants of mortality among adult HIV patients in a rural, tertiary hospital in southeastern Nigeria, comparing mortality among various ART regimens. Methods. Retrospective cohort study of 1069 patients on ART between August 2008 and October 2013. Baseline CD4 counts, age, gender, and ART regimen were considered in this study. Kaplan-Meier method was used to estimate survival and Cox proportional hazards models to identify multivariate predictors of mortality. Median follow-up period was 24 months (IQR 6–45). Results. 78 (7.3%) patients died with 15.6% lost to followup. Significant independent predictors of mortality include age (>45), sex (male > female), baseline CD4 stage (<200), and ART combination. Adjusted mortality hazard was 3 times higher among patients with CD4 count <200 cells/μL than those with counts >500 (95% CI 1.69–13.59). Patients on Truvada-based first-line regimens were 88% more likely to die than those on Combivir-based first line (95% CI 1.05–3.36), especially those with CD4 count <200 cells/μL. Conclusion. Study showed lower mortality than most studies in Nigeria and Africa, with mortality higher among males and patients with CD4 count <200. Further studies are recommended to further compare treatment outcomes between Combivir- and Truvada-based regimens in resource-limited settings using clinical indicators.

Resistance at Virological Failure Using Boosted Protease Inhibitors Versus Nonnucleoside Reverse Transcriptase Inhibitors As First-Line Antiretroviral Therapy—Implications for Sustained Efficacy of ART in Resource-Limited Settings

Increases in the prevalence of resistance to nonnucleoside reverse transcriptase inhibitors (NNRTIs) have been observed among previously untreated individuals in all areas of sub-Saharan Africa. We aimed to examine whether first-line use of 2 NRTIs plus a boosted protease inhibitor (bPI) could protect against emergence of NRTI resistance mutations, compared to the use of 2 NRTIs plus 1 NNRTI. We carried out a weighted meta-analysis of randomized clinical trials comparing bPI- with NNRTI-based first-line antiretroviral therapy regimens using random effects modeling. In intention to treat analyses, there was no difference in the risk of viral failure at week 48 between NNRTI and bPI (P = .19). At week 48, the overall difference between NNRTI- and PI-based regimens in selection of any major NRTI resistance mutation (crude unweighted prevalence 3.3% vs 1.6%) was 1.7% (95% confidence interval [CI], .4-3.0; P = .00927). There was a statistically significant difference in prevalence of K65R when comparing NNRTI (1.3%) with PI (0.67%); absolute weighted difference 1.0% (95% CI, .3-1.7; P = .00447). There was also a significant difference in prevalence of M184V/I between NNRTI and PI (crude unweighted prevalence 3.2% vs 1.4%); difference 1.6% (95% CI 0.1-3.1; P = .0368). Despite the equivalent efficacy and more favorable resistance implications of PI- versus NNRTI-based first line therapy, widespread use of PI-based first-line therapy is not warranted at this time, due to resource limitations and predicted increased risk of resistance-related failure of NNRTI/NRTI second-line regimens. PI-based first-line therapy could be reconsidered when antiretroviral agents from other classes become available for second-line regimens in resource-limited settings.

Pretreatment HIV-1 drug resistance in Africa

476 www.thelancet.com/infection Vol 13 June 2013 1 Hamers RL, Schuurman R, Sigaloff KCE, et al, for the PharmAccess African Studies to Evaluate Resistance (PASER) Investigators. Eff ect of pretreatment HIV-1 drug resistance on immunological, virological, and drugresistance outcomes of fi rst-line antiretroviral treatment in sub-Saharan Africa: a multicentre cohort study. Lancet Infect Dis 2012;12: 307–17. 2 Lynen L, Fransen K, Van Griensven J, Colebunders R. Pretreatment HIV-1 drug resistance testing in sub-Saharan Africa. Lancet Infect Dis 2012; 12: 911. 3 Roberts T, Bygrave H, Fajardo E, Ford N. Challenges and opportunities for the implementation of virological testing in resource-limited settings. J Int AIDS Soc; 15: 17324. 4 Hamers RL, Sawyer AW, Tuohy M, Stevens WS, Rinke de Wit TF, Hill AM. Cost-eff ectiveness of laboratory monitoring for management of HIV treatment in sub-Saharan Africa: a model-based analysis. AIDS 2012; 26: 1663–72. 5 Sigaloff KC, Hamers RL, Wallis CL, et al. Unnecessary antiretroviral treatment switches and accumulation of HIV resistance mutations; two arguments for viral load monitoring in Africa. J Acquir Immune Defi c Syndr 2011; 58: 23–31. 6 Nichols BE, Sigaloff KC, Kityo C, et al. Benefi ts of early antiretroviral treatment initiation outweigh risk of transmitted HIV drug resistance: a modelling study of two east African settings. 20th Conference on Retroviruses and Opportunistic Infections; March 3–6, 2013; Atlanta, GA. Abstr 1116. 7 Phillips AN, Pillay D, Garnett G, et al. Eff ect on transmission of HIV-1 resistance of timing of implementation of viral load monitoring to determine switches from fi rst to second-line antiretroviral regimens in resource-limited settings. AIDS 2011; 25: 843–50. 8 Gupta RK, Jordan MR, Sultan BJ, et al. Global trends in antiretroviral resistance in treatment-naive individuals with HIV after rollout of antiretroviral treatment in resource-limited settings: a global collaborative study and meta-regression analysis. Lancet 2012, 380: 1250–58. test ing and alternative fi rst-line regimens. Accurate ident ifi cation of virological failure will preserve drug options by avoiding the incremental cost of unnecessary switches and reducing drugresistance accumulation. Moreover, mathematical models predict that access to viral-load monitoring and second-line regimens might mitigate transmitted drug resistance. A shift to protease inhibitors in fi rst-line ART is regarded as a last resort by many experts, since this would have major programmatic implications, increase drug cost, and restrict options for constructing eff ective second-line regimens. Routine pretreatment drug-resistance testing is not feasible for most ART programmes because of restricted resources and laboratory capacity. As levels of transmitted drug resistance increase in east and southern Africa, we argue that improved functioning of national HIV treatment programmes will be crucial to preserve the longterm eff ectiveness of available ART regimens. Functioning would be improved by an uninterrupted drug supply, optimised patient adherence and retention, and access to viral-load monitoring.

Stavudine Concentrations in Women Receiving Postpartum Antiretroviral Treatment and Their Breastfeeding Infants

First-line antiretroviral treatment regimens in resource-limited settings used in breastfeeding mothers often include stavudine (d4T). Limited data describing d4T concentrations in breast milk are available. We analyzed d4T concentrations in 52 mother-infant pairs using ultra-performance liquid chromatography-tandem mass spectrometry (lower limit of quantification: 5 ng/mL in plasma, 20 ng/mL in breast milk). Median (interquartile range) d4T concentrations were 86 (36-191) ng/mL in maternal plasma, 151 (48-259) ng/mL in whole milk, 190 (58-296) ng/mL in skim milk, and <5 (<5 to <5) ng/mL in infant plasma. Although d4T is concentrated in breast milk relative to maternal plasma, the infant d4T dose received from breast milk is very small and not clinically significant.

Improved Neuropsychological and Neurological Functioning Across Three Antiretroviral Regimens in Diverse Resource-Limited Settings: AIDS Clinical Trials Group Study A5199, the International Neurological Study

AIDS Clinical Trials Group (ACTG) A5199 compared the neurological and neuropsychological (NP) effects of 3 antiretroviral regimens in participants infected with human immunodeficiency virus type 1 (HIV-1) in resource-limited settings. Participants from Brazil, India, Malawi, Peru, South Africa, Thailand, and Zimbabwe were randomized to 3 antiretroviral treatment arms: A (lamivudine-zidovudine plus efavirenz, n = 289), B (atazanavir, emtricitabine, and didanosine-EC, n = 293), and C (emtricitabine-tenofovir-disoproxil fumarate plus efavirenz, n = 278) as part of the ACTG PEARLS study (A5175). Standardized neurological and neuropsychological (NP) screening examinations (grooved pegboard, timed gait, semantic verbal fluency, and finger tapping) were administered every 24 weeks from February 2006 to May 2010. Associations with neurological and neuropsychological function were estimated from linear and logistic regression models using generalized estimating equations. The median weeks on study was 168 (Q1 = 96, Q3 = 192) for the 860 participants. NP test scores improved (P < .05) with the exception of semantic verbal fluency. No differences in neurological and neuropsychological functioning between treatment regimens were detected (P > .10). Significant country effects were noted on all NP tests and neurological outcomes (P < .01). The study detected no significant differences in neuropsychological and neurological outcomes between randomized ART regimens. Significant improvement occurred in neurocognitive and neurological functioning over time after initiation of ARTs. The etiology of these improvements is likely multifactorial, reflecting reduced central nervous system HIV infection, better general health, and practice effects. This study suggests that treatment with either of the World Health Organization -recommended first-line antiretroviral regimens in resource-limited settings will improve neuropsychological functioning and reduce neurological dysfunction. NCT00096824.

Frequent Emergence of N348I in HIV-1 Subtype C Reverse Transcriptase with Failure of Initial Therapy Reduces Susceptibility to Reverse-Transcriptase Inhibitors

It is not known how often mutations in the connection and ribonuclease H domains of reverse transcriptase (RT) emerge with failure of first-line antiretroviral therapy (ART) in subtype C human immunodeficiency virus type 1 (HIV-1) infection and how these mutations affect susceptibility to other antiretrovirals. We compared full-length RT sequences in plasma obtained before therapy and at virologic failure of initial ART among 63 participants with subtype C HIV-1 infection enrolled in the Comprehensive International Program of Research on AIDS in South Africa (CIPRA-SA) study. Recombinant viruses containing full-length plasma-derived RT sequences from participants with N348I at virologic failure were assayed for drug susceptibility. Y181C and M184V mutations in the RT polymerase domain were associated with failure of stavudine-lamivudine-nevirapine (d4T/3TC/NVP; P < .01), and K103N, V106M, and M184V with failure of d4T/3TC/efavirenz (EFV; P < .01). N348I in the RT connection domain emerged in 45% (P = .002) and 12% (P = .06) of participants receiving failing regimens containing NVP or EFV, respectively. Longitudinal analyses revealed that nonnucleoside RT inhibitor resistance mutations in the polymerase domain generally appeared first. N348I emerged at the same time, or after, M184V. N348I in the context of polymerase domain mutations reduced susceptibility to NVP (8.9-13-fold), EFV (4-56-fold), etravirine (ETV; 1.9-4.7-fold) and decreased hypersusceptibility to zidovudine (AZT; 1.4-2.2-fold). N348I emerges frequently with virologic failure of first-line ART in subtype C HIV-1 infection and reduces susceptibility to NVP, EFV, ETV, and AZT. Additional studies are warranted to characterize the effects of N348I on virologic response to second- and third-line regimens in resource-limited settings where subtype C predominates.

HIV-1 Drug Resistance Resulting from Antiretroviral Therapy Far Exceeds That From Pre-exposure Prophylaxis

To the Editor—We challenge the conclusions drawn by Hurt et al in their Viewpoint article “Pre-exposure Prophylaxis and Antiretroviral Resistance: HIV Prevention at a Cost?” The authors cite the very few cases of human immunodeficiency virus (HIV) drug resistance that have occurred in seroconverters from trials of pre-exposure prophylaxis (PrEP) as evidence of the potential for PrEP to jeopardize the long-term utility of tenofovir (TFV) and emtricitabine (FTC) in first-line treatment regimens in resource-limited settings. They also speculate that the possible increase in resistance from PrEP could offset the enormous benefit of preventing HIV infection in at-risk populations [1]. To date, only 3 cases of resistance from PrEP have occurred in a total of 80 seroconverters on active antiretroviral (ARV) arms from 3 large HIV prevention trials: 0 of 35 sequenced in the TFV gel arm in the CAPRISA-004 clinical trial [2]; 2 of 36 in the oral TDF-FTC arm in the iPrEx study [3], and 1 of 9 in the TDF2 study [4]. All 3 cases had unrecognized acute HIV infection before being placed on TFV-containing PrEP. No cases of resistance have yet been identified in trial participants who became infected after starting ARV-containing gel or tablets. By contrast, first-line antiretroviral therapy (ART) fails to suppress viremia in 22% of persons on therapy [5] and up to 95% of those who fail ART have drug-resistant HIV-1 [6]. Given that >6.6 million persons worldwide have started ART [7], failure of ART to suppress viremia, rather than failure of PrEP to prevent HIV infection, is driving the spread of drug resistance in the developing world. Indeed, recent surveys report an increase in transmitted drug resistance in resource-limited settings, from previous estimates of <5% using World Health Organization threshold surveys conducted before 2008 [8] to as high as 12.3% in various regions in sub–Saharan Africa, particularly in areas of treatment scale-up [9]. This increase has occurred as a consequence of ART roll-out without the influence of PrEP. More than 681 000 lives have been saved from expanding treatment roll-out [10], and an effective PrEP agent has the potential for further impact by preventing HIV-1 infection in the first place. Drug resistance will always be a risk with the use of antiretrovirals, but exaggeration of risk serves no purpose other than to raise fear and impede progress toward ending the AIDS epidemic.

Safety and effectiveness of efavirenz versus nevirapine-based regimens in resource-limited settings

639–641Keywords: efavirenz, effectiveness, modelling, nevirapine, safety,sub-Saharan AfricaCombination antiretroviral therapy (ART) with eitherefavirenz (EFV) or nevirapine (NVP), both nonnucleo-side reverse transcriptase inhibitors (NNRTIs), and twonucleoside reverse transcriptase inhibitors (NRTI) isrecommended by the WHO as first-line therapy inresource-limited countries [1]. Compared with NVP,EFV is easier to monitor, is relatively well tolerated, hasless frequent and less severe rash and hepatic toxicity thanNVP, and can be administered once daily. Whereas NVPandEFVhavegenerallycomparableclinicalandvirologicefficacy [2–5], because of lower drug–drug interactions,EFV-based ART is associated with superior virologicoutcome compared with NVP-based ART in individualswith tuberculosis (TB) receiving anti-TB therapycontaining rifampicin. Therefore, efavirenz is theNNRTI antiretroviral drug of choice of TB-coinfectedindividuals [6–9]. However, there have been concernsregarding potential for central nervous system birthdefects with first-trimester exposure to EFV based onstudiesinpregnantrhesusmacaquesandretrospectivecasereportsinhumansthathavelimitedEFVuseinwomenofchildbearing age. This is a problem in many resource-limitedsettings,wherewomenconstitute50%or moreofHIV-infected individuals and TB is endemic, but there islimited access to contraception or women may wish tobecome pregnant.In this issue, Ouattara and colleagues use a computersimulation model to evaluate the risks and benefits ofusing EFV and NVP in women of childbearing age inresource-limited countries [10]. Using the previouslyvalidated Cost-Effectiveness of Preventing AIDS Com-plications (CEPAC) International model, the authorssimulated the trade-off between potential excess birthdefects and potential long-term clinical benefits forwomen starting EFV-based versus NVP-based ART inCote d’Ivoire. In a ‘hypothetical’ cohort of 100000women starting ARTwith EFV, the authors found that adrug with lower toxicity and requiring less regimenswitching led to approximately 911 more women aliveafter 10 years compared with those starting with NVP, animprovement in survival of approximately 1%. However,over thesameperiod,therewere59morebirthdefectsinwomen initiating EFV-based ART than those startingwith NVP. The authors concluded that in Cote d’Ivoire,initiating ART with EFV instead of NVP is likely to

Comparative effectiveness of efavirenz-based antiretroviral regimens in resource-limited settings

Efavirenz (EFV) is a non-nucleoside widely used as first-line therapy for HIV-1 infection. Most of the research available on EFV comes from trials performed in industrialized countries and only a few studies have evaluated EFV in resource-limited settings (RLSs). In this article, we present a systematic review of the available randomized-controlled trials performed in RLSs that have compared EFV with other antiretrovirals, such as nevirapine and protease inhibitors. The data derived from these studies show that both EFV and nevirapine are adequate first-line therapy options for HIV-1 infection in RLSs, even in patients with concomitant tuberculosis. However, EFV may show a slight benefit in terms of toxicity and adverse events. By contrast, the data comparing EFV versus protease inhibitors is contradictory and further studies may be required to elucidate these discrepancies.

Effect on transmission of HIV-1 resistance of timing of implementation of viral load monitoring to determine switches from first to second-line antiretroviral regimens in resource-limited settings

There is concern that antiretroviral therapy (ART) use with only clinical monitoring for failure will result in high rates of transmission of virus with resistance to drugs currently in use. A stochastic simulation model of transmission of HIV, natural history and the effect of ART, was developed and used to predict the proportion of new infections with resistance according to whether and when viral load monitoring is introduced. In our base model, there was predicted to be 12.4% of new HIV infections with primary antiretroviral resistance in 2020 if clinical monitoring is used throughout, compared with 5.4 and 6.1% if viral load-guided switching (based on viral load measured every 6 months, with switch determined by a value >500 copies/ml) was introduced in 2010 or 2015, respectively. The death rate for those on ART was lowest when viral load monitoring was used, but the overall death rate in all infected people was higher if viral load monitoring was introduced at the expense of scale-up in HIV diagnosis and ART initiation beyond their 2010 coverage levels (4.7 compared with 3.1 per 100 person-years). To preserve current first-line drugs for the long term there is an eventual need for some form of cheap and practical viral load monitoring in resource-limited settings. However, a delay in introduction of 5 years has limited consequences for resistance transmission so the current priority for countries' ART programmes is to increase HIV testing and provide treatment for all those in need of ART.

Triple-Class Virologic Failure in HIV-Infected Patients Undergoing Antiretroviral Therapy for Up to 10 Years

Life expectancy of people with human immunodeficiency virus (HIV) is now estimated to approach that of the general population in some successfully treated subgroups. However, to attain these life expectancies, viral suppression must be maintained for decades. We studied the rate of triple-class virologic failure (TCVF) in patients within the Collaboration of Observational HIV Epidemiological Research Europe (COHERE) who started antiretroviral therapy (ART) that included a nonnucleoside reverse-transcriptase inhibitor (NNRTI) or a ritonavir-boosted protease inhibitor (PI/r) from 1998 onwards. We also focused on TCVF in patients who started a PI/r-containing regimen after a first-line NNRTI-containing regimen failed. Of 45 937 patients followed up for a median (interquartile range) of 3.0 (1.5-5.0) years, 980 developed TCVF (2.1%). By 5 and 9 years after starting ART, an estimated 3.4% (95% confidence interval [CI], 3.1%-3.6%) and 8.6% (95% CI, 7.5%-9.8%) of patients, respectively, had developed TCVF. The incidence of TCVF rose during the first 3 to 4 years on ART but plateaued thereafter. There was no significant difference in the risk of TCVF according to whether the initial regimen was NNRTI or PI/r based (P = .11). By 5 years after starting a PI/r regimen as second-line therapy, 46% of patients had developed TCVF. The rate of virologic failure of the 3 original drug classes is low, but not negligible, and does not appear to diminish over time from starting ART. If this trend continues, many patients are likely to need newer drugs to maintain viral suppression. The rate of TCVF from the start of a PI/r regimen after NNRTI failure provides a comparator for studies of response to second-line regimens in resource-limited settings.