Viral resuppression and detection of drug resistance following interruption of a suppressive non-nucleoside reverse transcriptase inhibitor-based regimen

HIV-1 pretreatment drug resistance negatively impacts outcomes of first-line antiretroviral treatment

INTRODUCTION

Pretreatment drug resistance (PDR) prevalence in sub-Saharan Africa is rising, but evidence of its impact on efavirenz (EFV)-based antiretroviral treatment (ART) is inconclusive. We determined the impact of PDR on outcomes of EFV-based ART in a subanalysis of a randomized clinical trial comparing different ART monitoring strategies implemented at a rural treatment facility in Limpopo, South Africa.

METHODS

Participants initiating EFV-based first-line ART (2015-2017) were enrolled and received 96 weeks follow-up. Resistance to nucleos(t)ide reverse transcriptase inhibitors (NRTIs) and non-NRTI's (NNRTIs) was retrospectively assessed by population-based sequencing. Virological failure was defined as a viral load of at least 1000 copies/ml after at least 24 weeks of ART.

RESULTS

A total of 207 participants were included, 60.4% (125/207) of whom were female. Median age was 38.8 (interquartile range: 31.4-46.7) years. Median CD4+ cell count was 191 (interquartile range: 70-355) cells/μl. PDR was detected in 12.9% (25/194) of participants with available sequencing results; 19 had NNRTI-resistance, and six had NRTI- and NNRTI-resistance. 26.0% of participants (40/154) with sequencing results and virological follow-up developed virological failure. PDR was independently associated with failure (adjusted hazard ratio: 3.7 [95% confidence interval: 1.68.5], P = 0.002). At failure, 87.5% (7/8) of participants with PDR harboured dual-class resistant virus, versus 16.7% (4/24) of participants without PDR (P = 0.0007). Virological resuppression after failure on first-line ART occurred in 57.7% (15/26) of participants without PDR versus 14.3% (1/7) of participants with PDR (P = 0.09).

CONCLUSION

PDR was detected in 13% of study participants. PDR significantly increased the risk of virological failure of EFV-based ART. Accumulation of resistance at failure and inability to achieve virological resuppression illustrates the profound impact of PDR on treatment outcomes.

Incidence and Predictors of Viral Load Suppression After Enhanced Adherence Counseling Among HIV-Positive Adults in West Gojjam Zone, Amhara Region, Ethiopia

Background

Methods

Results

Conclusion

Understanding patterns of HIV multi-drug resistance through models of temporal and spatial drug heterogeneity

Triple-drug therapies have transformed HIV from a fatal condition to a chronic one. These therapies should prevent HIV drug resistance evolution, because one or more drugs suppress any partially resistant viruses. In practice, such therapies drastically reduced, but did not eliminate, resistance evolution. In this article, we reanalyze published data from an evolutionary perspective and demonstrate several intriguing patterns about HIV resistance evolution - resistance evolves (1) even after years on successful therapy, (2) sequentially, often via one mutation at a time and (3) in a partially predictable order. We describe how these observations might emerge under two models of HIV drugs varying in space or time. Despite decades of work in this area, much opportunity remains to create models with realistic parameters for three drugs, and to match model outcomes to resistance rates and genetic patterns from individuals on triple-drug therapy. Further, lessons from HIV may inform other systems.

The Promise of Improved Adherence With Long-Acting Antiretroviral Therapy: What Are the Data?

As with other chronic conditions, adherence to daily medications remains a challenge for many individuals living with HIV due to structural, behavioral, and social barriers. Unfortunately, high levels of adherence to antiretroviral therapy are required to maintain virologic suppression. Alternative approaches are being explored to decrease the burden of daily pill administration, including long-acting injectable, oral, and implantable products. Phase 3 data support the efficacy of nanoformulated injectable cabotegravir and rilpivirine for HIV treatment in patients with undetectable viremia, but we have yet to learn how this strategy may benefit those with medication adherence challenges. Despite this, the affected community and HIV providers are very interested in exploring the role of long-acting therapies to address some types of barriers to medication adherence. This review summarizes available information about the potential for long-acting therapy to improve adherence for some patients and outlines associated opportunities and challenges with the implementation of long-acting therapy for the treatment and prevention of HIV.

HIV-1 re-suppression on a first-line regimen despite the presence of phenotypic drug resistance

We have previously reported on HIV-1 infected patients who fail anti-retroviral therapy but manage to re-suppress without a regimen change despite harbouring major drug resistance mutations. Here we explore phenotypic drug resistance in such patients in order to better understand this phenomenon. Patients (n = 71) failing a non-nucleoside reverse transcriptase inhibitor (NNRTI)-based regimen, but who subsequently re-suppressed on the same regimen, were assessed for HIV-1 genotypic drug resistance through Sanger sequencing. A subset (n = 23) of these samples, as well as genotypically matched samples from patients who did not re-suppress (n = 19), were further assessed for phenotypic drug resistance in an in vitro single cycle assay. Half of the patients (n = 36/71, 51%) harboured genotypic drug resistance, with M184V (n = 18/36, 50%) and K103N (n = 16/36, 44%) being the most prevalent mutations. No significant difference in the median time to re-suppression (31–39 weeks) were observed for either group (p = 0.41). However, re-suppressors with mutant virus rebounded significantly earlier than those with wild-type virus (16 vs. 33 weeks; p = 0.014). Similar phenotypic drug resistance profiles were observed between patients who re-suppressed and patients who failed to re-suppress. While most remained susceptible to stavudine (d4T) and zidovudine (AZT), both groups showed a reduced susceptibility to 3TC and NNRTIs. HIV- 1 infected patients on an NNRTI-based regimen can achieve viral re-suppression on the same regimen despite harbouring viruses with genotypic and phenotypic drug resistance. However, re-suppression was less durable in those with resistance, reinforcing the importance of appropriate regimen choices, ongoing viral load monitoring and adherence counselling.

Time to rethink endpoints for new clinical trials of antiretrovirals? Long-term re-suppression of HIV RNA with integrase inhibitors

: In the ADVANCE study of first-line treatment, there were 48 participants with HIV RNA at least 50 copies/ml in the week 48 window who had subsequent follow-up data available with no change in randomized treatment. More participants achieved virological re-suppression in the TAF/FTC+DTG and TDF/FTC+DTG arms (26/34, 76%) than on TDF/FTC/EFV (6/14 = 43%; P = 0.0421). It is unclear whether participants with HIV RNA at least 50 copies/ml at week 48 should be termed 'virological failures' on integrase inhibitor-based treatment.

Successes and challenges in optimizing the viral load cascade to improve antiretroviral therapy adherence and rationalize second-line switches in Swaziland

INTRODUCTION

As antiretroviral therapy (ART) is scaled up, more patients become eligible for routine viral load (VL) monitoring, the most important tool for monitoring ART efficacy. For HIV programmes to become effective, leakages along the VL cascade need to be minimized and treatment switching needs to be optimized. However, many HIV programmes in resource-constrained settings report significant shortfalls.

METHODS

From a public sector HIV programme in rural Swaziland, we evaluated the VL cascade of adults (≥18 years) on ART from the time of the first elevated VL (>1000 copies/mL) between January 2013 and June 2014 to treatment switching by December 2015. We additionally described HIV drug resistance for patients with virological failure. We used descriptive statistics and Kaplan-Meier estimates to describe the different steps along the cascade and regression models to determine factors associated with outcomes.

RESULTS AND DISCUSSION

Of 828 patients with a first elevated VL, 252 (30.4%) did not receive any enhanced adherence counselling (EAC). Six hundred and ninety-six (84.1%) patients had a follow-up VL measurement, and the predictors of receiving a follow-up VL were being a second-line patient (adjusted hazard ratio (aHR): 0.72; p = 0.051), Hlathikhulu health zone (aHR: 0.79; p = 0.013) and having received two EAC sessions (aHR: 1.31; p = 0.023). Four hundred and ten patients (58.9%) achieved VL re-suppression. Predictors of re-suppression were age 50 to 64 (adjusted odds ratio (aOR): 2.02; p = 0.015) compared with age 18 to 34 years, being on second-line treatment (aOR: 3.29; p = 0.003) and two (aOR: 1.66; p = 0.045) or three (aOR: 1.86; p = 0.003) EAC sessions. Of 278 patients eligible to switch to second-line therapy, 120 (43.2%) had switched by the end of the study. Finally, of 155 successfully sequenced dried blood spots, 144 (92.9%) were from first-line patients. Of these, 133 (positive predictive value: 92.4%) had resistance patterns that necessitated treatment switching.

CONCLUSIONS

Patients on ART with high VLs were more likely to re-suppress if they received EAC. Failure to re-suppress after counselling was predictive of genotypically confirmed resistance patterns requiring treatment switching. Delays in switching were significant despite the ability of the WHO algorithm to predict treatment failure. Despite significant progress in recent years, enhanced focus on quality care along the VL cascade in resource-limited settings is crucial.

Molecular Epidemiology of HIV-1 Virus in Puerto Rico: Novel Cases of HIV-1 Subtype C, D, and CRF-24BG

HIV-1 subtype B virus is the most prevalent subtype in Puerto Rico (PR), accounting for about 90% of infection in the island. Recently, other subtypes and circulating recombinant forms (CRFs), including F(12_BF), A (01_BF), and CRF-39 BF-like, have been identified. The purpose of this study is to assess the distribution of drug resistance mutations and subtypes in PR. A total of 846 nucleotide sequences from the period comprising 2013 through 2017 were obtained from our "HIV Genotyping" test file. Phylogenetic and molecular epidemiology analyses were performed to evaluate the evolutionary dynamics and prevalence of drug resistance mutations. According to our results, we detected a decrease in the prevalence of protease inhibitor, nucleoside reverse transcriptase inhibitor (NRTI), and non-NRTI (NNRTI) resistance mutations over time. In addition, we also detected recombinant forms and, for the first time, identified subtypes C, D, and CRF-24BG in PR. Recent studies suggest that non-subtypes B are associated with a high risk of treatment failure and disease progression. The constant monitoring of viral evolution and drug resistance mutation dynamics is important to establish appropriate efforts for controlling viral expansion.

Intermittent treatment of severe influenza

Severe, long-lasting influenza infections are often caused by new strains of the virus. The long duration of these infections leads to an increased opportunity for the emergence of drug resistant mutants. This is particularly problematic since for new strains there is often no vaccine, so drug treatment is the first line of defense. One strategy for trying to minimize drug resistance is to apply drugs periodically. During treatment phases the wild-type virus decreases, but resistant virus might increase; when there is no treatment, wild-type virus will hopefully out-compete the resistant virus, driving down the number of resistant virus. A stochastic model of severe influenza is combined with a model of drug resistance to simulate long-lasting infections and intermittent treatment with two types of antivirals: neuraminidase inhibitors, which block release of virions; and adamantanes, which block replication of virions. Each drug's ability to reduce emergence of drug resistant mutants is investigated. We find that cell regeneration is required for successful implementation of intermittent treatment and that the optimal cycling parameters change with regeneration rate.

Virological response and resistance among HIV-infected children receiving long-term antiretroviral therapy without virological monitoring in Uganda and Zimbabwe: Observational analyses within the randomised ARROW trial

BACKGROUND

Although WHO recommends viral load (VL) monitoring for those on antiretroviral therapy (ART), availability in low-income countries remains limited. We investigated long-term VL and resistance in HIV-infected children managed without real-time VL monitoring.

METHODS AND FINDINGS

In the ARROW factorial trial, 1,206 children initiating ART in Uganda and Zimbabwe between 15 March 2007 and 18 November 2008, aged a median 6 years old, with median CD4% of 12%, were randomised to monitoring with or without 12-weekly CD4 counts and to receive 2 nucleoside reverse transcriptase inhibitors (2NRTI, mainly abacavir+lamivudine) with a non-nucleoside reverse transcriptase inhibitor (NNRTI) or 3 NRTIs as long-term ART. All children had VL assayed retrospectively after a median of 4 years on ART; those with >1,000 copies/ml were genotyped. Three hundred and sixteen children had VL and genotypes assayed longitudinally (at least every 24 weeks). Overall, 67 (6%) switched to second-line ART and 54 (4%) died. In children randomised to WHO-recommended 2NRTI+NNRTI long-term ART, 308/378 (81%) monitored with CD4 counts versus 297/375 (79%) without had VL <1,000 copies/ml at 4 years (difference = +2.3% [95% CI -3.4% to +8.0%]; P = 0.43), with no evidence of differences in intermediate/high-level resistance to 11 drugs. Among children with longitudinal VLs, only 5% of child-time post-week 24 was spent with persistent low-level viraemia (80-5,000 copies/ml) and 10% with VL rebound ≥5,000 copies/ml. No child resuppressed <80 copies/ml after confirmed VL rebound ≥5,000 copies/ml. A median of 1.0 (IQR 0.0,1.5) additional NRTI mutation accumulated over 2 years' rebound. Nineteen out of 48 (40%) VLs 1,000-5,000 copies/ml were immediately followed by resuppression <1,000 copies/ml, but only 17/155 (11%) VLs ≥5,000 copies/ml resuppressed (P < 0.0001). Main study limitations are that analyses were exploratory and treatment initiation used 2006 criteria, without pre-ART genotypes.

CONCLUSIONS

In this study, children receiving first-line ART in sub-Saharan Africa without real-time VL monitoring had good virological and resistance outcomes over 4 years, regardless of CD4 monitoring strategy. Many children with detectable low-level viraemia spontaneously resuppressed, highlighting the importance of confirming virological failure before switching to second-line therapy. Children experiencing rebound ≥5,000 copies/ml were much less likely to resuppress, but NRTI resistance increased only slowly. These results are relevant to the increasing numbers of HIV-infected children receiving first-line ART in sub-Saharan Africa with limited access to virological monitoring.

TRIAL REGISTRATION

ISRCTN Registry, ISRCTN24791884.

Decreased emergence of HIV-1 drug resistance mutations in a cohort of Ugandan women initiating option B+ for PMTCT

BACKGROUND

Since 2012, WHO guidelines for the prevention of mother-to-child transmission (PMTCT) of HIV-1 in resource-limited settings recommend the initiation of lifelong antiretroviral combination therapy (cART) for all pregnant HIV-1 positive women independent of CD4 count and WHO clinical stage (Option B+). However, long-term outcomes regarding development of drug resistance are lacking until now. Therefore, we analysed the emergence of drug resistance mutations (DRMs) in women initiating Option B+ in Fort Portal, Uganda, at 12 and 18 months postpartum (ppm).

METHODS AND FINDINGS

124 HIV-1 positive pregnant women were enrolled within antenatal care services in Fort Portal, Uganda. Blood samples were collected at the first visit prior starting Option B+ and postpartum at week six, month six, 12 and 18. Viral load was determined by real-time RT-PCR. An RT-PCR covering resistance associated positions in the protease and reverse transcriptase HIV-1 genomic region was performed. PCR-positive samples at 12/18 ppm and respective baseline samples were analysed by next generation sequencing regarding HIV-1 drug resistant variants including low-frequency variants. Furthermore, vertical transmission of HIV-1 was analysed. 49/124 (39.5%) women were included into the DRM analysis. Virological failure, defined as >1000 copies HIV-1 RNA/ml, was observed in three and seven women at 12 and 18 ppm, respectively. Sequences were obtained for three and six of these. In total, DRMs were detected in 3/49 (6.1%) women. Two women displayed dual-class resistance against all recommended first-line regimen drugs. Of 49 mother-infant-pairs no infant was HIV-1 positive at 12 or 18 ppm.

CONCLUSION

Our findings suggest that the WHO-recommended Option B+ for PMTCT is effective in a cohort of Ugandan HIV-1 positive pregnant women with regard to the low selection rate of DRMs and vertical transmission. Therefore, these results are encouraging for other countries considering the implementation of lifelong cART for all pregnant HIV-1 positive women.

Acute Care Management of the HIV-Infected Patient: A Report from the HIV Practice and Research Network of the American College of Clinical Pharmacy

OBJECTIVE

Patients infected with human immunodeficiency virus (HIV) admitted to the hospital have complex antiretroviral therapy (ART) regimens with an increased medication error rate upon admission. This report provides a resource for clinicians managing HIV-infected patients and ART in the inpatient setting.

METHODS

A survey of the authors was conducted to evaluate common issues that arise during an acute hospitalization for HIV-infected patients. After a group consensus, a review of the medical literature was performed to determine the supporting evidence for the following HIV-associated hospital queries: admission/discharge orders, antiretroviral hospital formularies, laboratory monitoring, altered hepatic/renal function, drug-drug interactions (DDIs), enteral administration, and therapeutic drug monitoring.

RESULTS

With any hospital admission for an HIV-infected patient, a specific set of procedures should be followed including a thorough admission medication history and communication with the ambulatory HIV provider to avoid omissions or substitutions in the ART regimen. DDIs are common and should be reviewed at all transitions of care during the hospital admission. ART may be continued if enteral nutrition with a feeding tube is deemed necessary, but the entire regimen should be discontinued if no oral access is available for a prolonged period. Therapeutic drug monitoring is not generally recommended but, if available, should be considered in unique clinical scenarios where antiretroviral pharmacokinetics are difficult to predict. ART may need adjustment if hepatic or renal insufficiency ensues.

CONCLUSIONS

Treatment of hospitalized patients with HIV is highly complex. HIV-infected patients are at high risk for medication errors during various transitions of care. Baseline knowledge of the principles of antiretroviral pharmacotherapy is necessary for clinicians managing acutely ill HIV-infected patients to avoid medication errors, identify DDIs, and correctly dose medications if organ dysfunction arises. Timely ambulatory follow-up is essential to prevent readmissions and facilitate improved transitions of care.

Antiviral drug resistance as an adaptive process

Antiviral drug resistance is a matter of great clinical importance that, historically, has been investigated mostly from a virological perspective. Although the proximate mechanisms of resistance can be readily uncovered using these methods, larger evolutionary trends often remain elusive. Recent interest by population geneticists in studies of antiviral resistance has spurred new metrics for evaluating mutation and recombination rates, demographic histories of transmission and compartmentalization, and selective forces incurred during viral adaptation to antiviral drug treatment. We present up-to-date summaries on antiviral resistance for a range of drugs and viral types, and review recent advances for studying their evolutionary histories. We conclude that information imparted by demographic and selective histories, as revealed through population genomic inference, is integral to assessing the evolution of antiviral resistance as it pertains to human health.

Effects of unplanned treatment interruptions on HIV treatment failure - results from TAHOD

OBJECTIVES

Treatment interruptions (TIs) of combination antiretroviral therapy (cART) are known to lead to unfavourable treatment outcomes but do still occur in resource-limited settings. We investigated the effects of TI associated with adverse events (AEs) and non-AE-related reasons, including their durations, on treatment failure after cART resumption in HIV-infected individuals in Asia.

METHODS

Patients initiating cART between 2006 and 2013 were included. TI was defined as stopping cART for >1 day. Treatment failure was defined as confirmed virological, immunological or clinical failure. Time to treatment failure during cART was analysed using Cox regression, not including periods off treatment. Covariables with P < 0.10 in univariable analyses were included in multivariable analyses, where P < 0.05 was considered statistically significant.

RESULTS

Of 4549 patients from 13 countries in Asia, 3176 (69.8%) were male and the median age was 34 years. A total of 111 (2.4%) had TIs due to AEs and 135 (3.0%) had TIs for other reasons. Median interruption times were 22 days for AE and 148 days for non-AE TIs. In multivariable analyses, interruptions >30 days were associated with failure (31-180 days HR = 2.66, 95%CI (1.70-4.16); 181-365 days HR = 6.22, 95%CI (3.26-11.86); and >365 days HR = 9.10, 95% CI (4.27-19.38), all P < 0.001, compared to 0-14 days). Reasons for previous TI were not statistically significant (P = 0.158).

CONCLUSIONS

Duration of interruptions of more than 30 days was the key factor associated with large increases in subsequent risk of treatment failure. If TI is unavoidable, its duration should be minimised to reduce the risk of failure after treatment resumption.

Proposal of Standardization to Assess Adherence With Medication Records: Methodology Matters

BACKGROUND

Medication adherence is the process by which patients take their medication as prescribed and is an umbrella term that encompasses all aspects of medication use patterns. Ambiguous terminology has emerged to describe a deviation from prescribed regimen, forcing the European ABC Project to define 3 phases of medication use: initiation, implementation, and discontinuation. However, different measures of medication adherence using medication records are currently available that do not always distinguish between these phases. The literature is lacking standardization and operationalization of the assessment methods.

OBJECTIVE

To propose a harmonization of standards as well as definitions of distinct measures and their operationalization to quantify adherence to medication from medication records.

METHODS

Group discussions and consensus process among all coauthors. The propositions were generated using the authors' experiences and views in the field of adherence, informed by theory.

RESULTS

The concepts of adherence measures within the new taxonomy were harmonized, and the standards necessary for the operationalization of adherence measures from medication records are proposed. Besides percentages and time-to values, the addition of a dichotomous value for the reinitiation of treatment is proposed. Methodological issues are listed that should be disclosed in studies on adherence.

CONCLUSIONS

The possible impact of the measures in adherence research is discussed. By doing this, the results of future adherence research should gain in accuracy. Finally, studies will become more transparent, enabling comparison between studies.

Global HIV-1 transmitted drug resistance in the INSIGHT Strategic Timing of AntiRetroviral Treatment (START) trial

OBJECTIVES

HIV-1 transmitted drug resistance (TDR) in treatment-naïve individuals is a well-described phenomenon. Baseline genotypic resistance testing is considered standard of care in most developed areas of the world. The aim of this analysis was to characterize HIV-1 TDR and the use of resistance testing in START trial participants.

METHODS

In the Strategic Timing of AntiRetroviral Treatment (START) trial, baseline genotypic resistance testing results were collected at study entry and analysed centrally to determine the prevalence of TDR in the study population. Resistance was based on a modified 2009 World Health Organization definition to reflect newer resistance mutations.

RESULTS

Baseline resistance testing was available in 1946 study participants. Higher rates of testing occurred in Europe (86.7%), the USA (81.3%) and Australia (89.9%) as compared with Asia (22.2%), South America (1.8%) and Africa (0.1%). The overall prevalence of TDR was 10.1%, more commonly to nonnucleoside reverse transcriptase inhibitors (4.5%) and nucleoside reverse transcriptase inhibitors (4%) compared with protease inhibitors (2.8%). The most frequent TDR mutations observed were M41L, D67N/G/E, T215F/Y/I/S/C/D/E/V/N, 219Q/E/N/R, K103N/S, and G190A/S/E in reverse transcriptase, and M46I/L and L90M in protease. By country, the prevalence of TDR was highest in Australia (17.5%), France (16.7%), the USA (12.6%) and Spain (12.6%). No participant characteristics were identified as predictors of the presence of TDR.

CONCLUSIONS

START participants enrolled in resource-rich areas of the world were more likely to have baseline resistance testing. In Europe, the USA and Australia, TDR prevalence rates varied by country.

Progress Toward HIV Eradication: Case Reports, Current Efforts, and the Challenges Associated with Cure

An estimated 35 million people worldwide are infected with HIV, yet a widely applicable cure strategy remains elusive. Recent case reports have suggested that curing HIV infection is possible, renewing excitement about research efforts. We describe those cases and discuss their relevance to the global HIV epidemic. We also review ongoing cure strategies that are transitioning from the lab to the clinic, and the assays and clinical assessments that can be used to evaluate cure interventions.

Effectiveness of a Treatment Switch to Nevirapine plus Tenofovir and Emtricitabine (or Lamivudine) in Adults with HIV-1 Suppressed Viremia

BACKGROUND

Switching subjects with persistently undetectable HIV-1 viremia under antiretroviral treatment (ART) to once-daily tenofovir/emtricitabine (or lamivudine) + nevirapine is a cost-effective and well-tolerated strategy. However, the effectiveness of this approach has not been established.

METHODS

We performed a retrospective study evaluating the rates of treatment failure, virological failure (VF), and variables associated, in all subjects initiating this switch combination in our clinic since 2001. Analyses were performed by a modified intention to treat, where switch due to toxicity equalled failure. The main endpoint was plasma HIV-RNA < 50 copies/mL.

RESULTS

341 patients were treated for a median of 176 (57; 308) weeks. At week 48, 306 (89.7%) subjects had HIV-1 RNA <50 copies/mL, 10 (2.9%) experienced VF, and 25 (7.4%) discontinued the treatment due to toxicity. During the whole follow-up 23 (6.7%) individuals (17 on lamivudine, 6 on emtricitabine; p = 0.034) developed VF and treatment modification due to toxicity occurred in 36 (10.7%). Factors independently associated with VF in a multivariate analysis were: intravenous drug use (HR 1.51; 95%CI 1.12, 2.04), time with undetectable viral load before the switch (HR 0.98; 0.97, 0.99), number of prior NRTIs (HR 1.49; 1.15, 1.93) or NNRTIs (HR 3.22; 1.64, 6.25), and previous NVP (HR 1.54; 1.10, 2.17) or efavirenz (HR 5.76; 1.11, 29.87) unscheduled interruptions. VF was associated with emergence of usual nevirapine mutations (Y181C/I/D, K103N and V106A/I), M184V (n = 16; 12 with lamivudine vs. 4 with emtricitabine, p = 0.04), and K65R (n = 7).

CONCLUSIONS

The rates of treatment failure at 48 weeks, or long-term toxicity or VF with this switch regimen are low and no unexpected mutations or patterns of mutations were selected in subjects with treatment failure.

Paediatric European Network for Treatment of AIDS (PENTA) guidelines for treatment of paediatric HIV-1 infection 2015: optimizing health in preparation for adult life

The 2015 Paediatric European Network for Treatment of AIDS (PENTA) guidelines provide practical recommendations on the management of HIV‐1 infection in children in Europe and are an update to those published in 2009. Aims of treatment have progressed significantly over the last decade, moving far beyond limitation of short‐term morbidity and mortality to optimizing health status for adult life and minimizing the impact of chronic HIV infection on immune system development and health in general. Additionally, there is a greater need for increased awareness and minimization of long‐term drug toxicity. The main updates to the previous guidelines include: an increase in the number of indications for antiretroviral therapy (ART) at all ages (higher CD4 thresholds for consideration of ART initiation and additional clinical indications), revised guidance on first‐ and second‐line ART recommendations, including more recently available drug classes, expanded guidance on management of coinfections (including tuberculosis, hepatitis B and hepatitis C) and additional emphasis on the needs of adolescents as they approach transition to adult services. There is a new section on the current ART ‘pipeline’ of drug development, a comprehensive summary table of currently recommended ART with dosing recommendations. Differences between PENTA and current US and World Health Organization guidelines are highlighted and explained.

Antiretroviral drugs for prevention of mother-to-child transmission: pharmacologic considerations for a public health approach

OBJECTIVE

Efavirenz-based antiretroviral therapy is recommended for prevention of mother-to-child transmission of HIV with two programmatic options: lifelong therapy for all women or treatment until cessation of breastfeeding. However, the risk of HIV resistance emerging after discontinuing efavirenz-based antiretroviral therapy is unclear. We review present knowledge surrounding the emergence of resistance after stopping efavirenz-based antiretroviral regimens.

DESIGN

An expert review.

METHODS

A literature review was conducted to identify studies assessing risk for emergence of efavirenz-related resistance following discontinuation of efavirenz-based antiretroviral regimens containing either lamivudine and zidovudine or tenofovir disoproxil fumarate and lamivudine. Discontinuation strategies including the use of 'pharmacologic tails' are discussed in the light of what is known about the pharmacology of the drugs.

RESULTS

We found no head-to-head comparisons between zidovudine, lamivudine and efavirenz and tenofovir disoproxil fumarate, lamivudine and efavirenz. The risk for HIV resistance exists, even with a 5-7 day tail of zidovudine and lamivudine. For tenofovir disoproxil fumarate, lamivudine and efavirenz, we found no clinical data to inform a recommendation for a tail.

CONCLUSION

In order to prevent emergence of resistance, a tail of at least 2 weeks in duration may be required when discontinuing efavirenz in a regimen containing zidovudine and lamivudine. Studies are needed to characterize the risk of resistance among women who discontinue tenofovir disoproxil fumarate, lamivudine and efavirenz.

Temporary treatment during primary HIV infection does not affect virologic response to subsequent long-term treatment

Temporary cART during primary HIV-infection (PHI) did not select for drug resistance mutations after treatment interruption and did not affect the subsequent virological response to long-term cART. Our data demonstrate that fear of drug resistance development is not a valid argument to refrain from temporary early treatment during PHI.

Durable HIV RNA resuppression after virologic failure while remaining on a first-line regimen: a cohort study

Adherence interventions are a recommended strategy to salvage failing antiretroviral therapy without regimen change. We assessed the durability of resuppression when using this approach. Of 300 patients who resuppressed on the same regimen (41% of all those with virologic failure), 148 (45%) remained suppressed during follow-up for a median of 2.4 years (interquartile range [IQR]: 1.1, 4.0). Resuppression can be durable following viraemia without a switch in antiretroviral therapy regimen.

[Consensus statement on monitoring of HIV: pregnancy, birth, and prevention of mother-to-child transmission]

OBJECTIVE

The main objective in the management of HIV-infected pregnant women is prevention of mother-to-child transmission; therefore, it is essential to provide universal antiretroviral treatment, regardless of CD4 count. All pregnant women must receive adequate information and undergo HIV serology testing at the first visit.

METHODS

We assembled a panel of experts appointed by the Secretariat of the National AIDS Plan (SPNS) and the other participating Scientific Societies, which included internal medicine physicians with expertise in the field of HIV infection, gynecologists, pediatricians and psychologists. Four panel members acted as coordinators. Scientific information was reviewed in publications and conference reports up to November 2012. In keeping with the criteria of the Infectious Diseases Society of America, 2levels of evidence were applied to support the proposed recommendations: the strength of the recommendation according to expert opinion (A, B, C), and the level of empirical evidence (I, II, III). This approach has already been used in previous documents from SPNS.

RESULTS AND CONCLUSIONS

The aim of this paper was to review current scientific knowledge, and, accordingly, develop a set of recommendations regarding antiretroviral therapy (ART), regarding the health of the mother, and from the perspective of minimizing mother-to-child transmission (MTCT), also taking into account the rest of the health care of pregnant women with HIV infection. We also discuss and evaluate other strategies to reduce the MTCT (elective Cesarean, child's treatment…), and different aspects of the topic (ARV regimens, their toxicity, monitoring during pregnancy and postpartum, etc.).

Predicted levels of HIV drug resistance: potential impact of expanding diagnosis, retention, and eligibility criteria for antiretroviral therapy initiation

BACKGROUND

There is concern that the expansion of antiretroviral roll-out may impact future drug resistance levels and hence compromise the benefits of antiretroviral therapy (ART) at an individual and population level. We aimed to predict future drug resistance in South Africa and its long-term effects.

METHODS

The previously validated HIV Synthesis model was calibrated to South Africa. Resistance was modeled at the level of single mutations, transmission potential, persistence, and effect on drug activity.

RESULTS

We estimate 652 000 people (90% uncertainty range: 543 000-744 000) are living with nonnucleoside reverse transcriptase inhibitor (NNRTIs)-resistant virus in South Africa, 275 000 in majority virus [Non-nucleoside reverse transcriptase inhibitor resistant virus present in majority virus (NRMV)] with an unsuppressed viral load. If current diagnosis and retention in care and eligibility criteria are maintained, in 20 years' time HIV incidence is projected to have declined by 22% (95% confidence interval, CI -23 to -21%), and the number of people carrying NNRTI resistance to be 2.9-fold higher. If enhancements in diagnosis and retention in care occur, and ART is initiated at CD4 cell count less than 500  cells/μl, HIV incidence is projected to decline by 36% (95% CI: -37 to -36%) and the number of people with NNRTI resistance to be 4.1-fold higher than currently. Prevalence of people with viral load more than 500  copies/ml carrying NRMV is not projected to differ markedly according to future ART initiation policy, given the current level of diagnosis and retention are maintained.

CONCLUSION

Prevalence of resistance is projected to increase substantially. However, introduction of policies to increase ART coverage is not expected to lead to appreciably higher prevalence of HIV-positive people with resistance and viral load more than 500  copies/ml. Concern over resistance should not stop expansion of treatment availability.

Salvage surgery for residual primary and locally recurrent anal squamous cell carcinoma after chemoradiotherapy in HIV-positive individuals

BACKGROUND

The treatment of anal cancer in human immunodeficiency virus (HIV) patients-as in the general population-is primarily with chemoradiotherapy (CRT), and abdominoperineal resection of residual or recurrent primary disease. The aim of this study was to evaluate the extent of residual primary disease and local recurrence as well as the outcome of salvage surgery after CRT for anal carcinoma in HIV-positive individuals.

METHODS

We retrospectively studied HIV-positive anal carcinoma patients treated between February 1989 and November 2012 in a specialist London unit. Extent of residual primary disease, local recurrence after CRT, postoperative complications, and survival after salvage surgery were evaluated.

RESULTS

Complete response was experienced in 44 of 53 (83%) of HIV patients treated with CRT for anal carcinoma. One patient (2.3%) developed local recurrence. Nine patients (eight residual primary disease after CRT and one local recurrence) underwent salvage surgery after CRT. There were no perioperative deaths, and perioperative CD4 counts were sustained. Complications occurred in five patients (55%). Median interval to complete perineal healing was 4 months (range 2-11 months), and median hospital stay was 29 days. Survival (median 16 months) was 25% at 2 years from salvage surgery.

CONCLUSIONS

Results in HIV-positive patients receiving highly active antiretroviral therapy (HAART) suggest that loss of HIV sensitivity to HAART can be avoided, but that there is increased postoperative morbidity that may be related to HIV disease. Survival was comparable to that for salvage therapy after optimal CRT in non-HIV anal carcinoma patients.

Sensitive assessment of the virologic outcomes of stopping and restarting non-nucleoside reverse transcriptase inhibitor-based antiretroviral therapy

BACKGROUND

Non-nucleoside reverse transcriptase inhibitor (NNRTI)-resistant mutants have been shown to emerge after interruption of suppressive NNRTI-based antiretroviral therapy (ART) using routine testing. The aim of this study was to quantify the risk of resistance by sensitive testing and correlate the detection of resistance with NNRTI concentrations after treatment interruption and virologic responses after treatment resumption.

METHODS

Resistance-associated mutations (RAMs) and NNRTI concentrations were studied in plasma from 132 patients who interrupted suppressive ART within SMART. RAMs were detected by Sanger sequencing, allele-specific PCR, and ultra-deep sequencing. NNRTI concentrations were measured by sensitive high-performance liquid chromatography.

RESULTS

Four weeks after NNRTI interruption, 19/31 (61.3%) and 34/39 (87.2%) patients showed measurable nevirapine (>0.25 ng/ml) or efavirenz (>5 ng/ml) concentrations, respectively. Median eight weeks after interruption, 22/131 (16.8%) patients showed ≥1 NNRTI-RAM, including eight patients with NNRTI-RAMs detected only by sensitive testing. The adjusted odds ratio (OR) of NNRTI-RAM detection was 7.62 (95% confidence interval [CI] 1.52, 38.30; p = 0.01) with nevirapine or efavirenz concentrations above vs. below the median measured in the study population. Staggered interruption, whereby nucleos(t)ide reverse transcriptase inhibitors (NRTIs) were continued for median nine days after NNRTI interruption, did not prevent NNRTI-RAMs, but increased detection of NRTI-RAMs (OR 4.25; 95% CI 1.02, 17.77; p = 0.03). After restarting NNRTI-based ART (n = 90), virologic suppression rates <400 copies/ml were 8/13 (61.5%) with NNRTI-RAMs, 7/11 (63.6%) with NRTI-RAMs only, and 51/59 (86.4%) without RAMs. The ORs of re-suppression were 0.18 (95% CI 0.03, 0.89) and 0.17 (95% CI 0.03, 1.15) for patients with NNRTI-RAMs or NRTI-RAMs only respectively vs. those without RAMs (p = 0.04).

CONCLUSIONS

Detection of resistant mutants in the rebound viremia after interruption of efavirenz- or nevirapine-based ART affects outcomes once these drugs are restarted. Further studies are needed to determine RAM persistence in untreated patients and impact on newer NNRTIs.

The ethics of clinical research in low- and middle-income countries

The increasing conduct of clinical research in low- and middle-income countries (LMIC) is motivated by the desire to promote host country access to biomedical research, to enhance LMIC access to modern clinical care, and opportunities to conduct research with simpler regulatory requirements and at lower cost. Yet clinical research in LMIC is associated with ethical risks beyond those of clinical research conducted in high-income countries (HIC). Ethical challenges particular to clinical research in LMIC include the conduct of placebo-controlled clinical trials in LMIC despite HIC availability of effective comparator interventions, obtaining informed consent despite power inequities, and the obligation of HIC researchers to redress health disparities in LMIC. This chapter covers these and additional ethical challenges of clinical research in LMIC, and proposes ways to navigate these challenges through awareness, regulatory oversight, consultation, and collaboration with LMIC investigators and community representatives. With its ethical challenges properly managed, clinical research in LMIC provides historic opportunities to bring biomedical research and better healthcare infrastructure to countries previously left behind in the modern rush to biomedical innovation.

Rates and predictors of failure of first-line antiretroviral therapy and switch to second-line ART in South Africa

OBJECTIVES

To measure rates and predictors of virologic failure and switch to second-line antiretroviral therapy (ART) in South Africa.

DESIGN

: Observational cohort study.

METHODS

We included ART-naive adult patients initiated on public sector ART (January 2000 to July 2008) at 5 sites in South Africa who completed ≥6 months of follow-up. We estimated cumulative risk of virologic failure (viral load ≥400 copies/mL with confirmation above varying thresholds) and switching to second-line ART.

RESULTS

Nineteen thousand six hundred forty-five patients (29,935 person-years) had a median of 1.3 years of study follow-up (1.8 years on ART) and a median CD4 count of 93 (IQR: 39-155) cells per microliter at ART initiation. About 9.9% (4.5 per 100 person-years) failed ART in median 16 (IQR: 12-23) months since ART initiation, with median 2.7 months (IQR: 1.6-4.7) months between first elevated and confirmatory viral loads. By survival analysis, using a confirmatory threshold of 400 copies per milliliter, 16.9% [95% confidence interval (CI): 15.4% to 18.6%] failed by 5 years on ART, but only 7.8% (95% CI: 6.6% to 9.3%) using a threshold of 10,000. CD4 <25 versus 100-199 (adjusted HR: 1.60; 95% CI: 1.37 to 1.87), ART initiation viral load ≥1,000,000 versus <10,000, (1.32; 0.91 to 1.93), and 2+ gaps in care versus 0 (95% CI: 7.25; 4.95 to 10.6) were predictive of failure. Overall, 10.1% (95% CI: 9.0% to 11.4%) switched to second-line by 5 years on ART. Lower CD4 at failure and higher rate of CD4 decline were predictive of switch (decline 100% to 51% versus 25% to -25%, adjusted HR: 1.96; 95% CI: 1.35 to 2.85).

CONCLUSIONS

In resource-limited settings with viral load monitoring, virologic failure rates are highly sensitive to thresholds for confirmation. Despite clear guidelines there is considerable variability in switching failing patients, partially in response to immunologic status and postfailure evolution.

Humanized mice recapitulate key features of HIV-1 infection: a novel concept using long-acting anti-retroviral drugs for treating HIV-1

BACKGROUND

Humanized mice generate a lymphoid system of human origin subsequent to transplantation of human CD34+ cells and thus are highly susceptible to HIV infection. Here we examined the efficacy of antiretroviral treatment (ART) when added to food pellets, and of long-acting (LA) antiretroviral compounds, either as monotherapy or in combination. These studies shall be inspiring for establishing a gold standard of ART, which is easy to administer and well supported by the mice, and for subsequent studies such as latency. Furthermore, they should disclose whether viral breakthrough and emergence of resistance occurs similar as in HIV-infected patients when ART is insufficient.

METHODS/PRINCIPAL FINDINGS

NOD/shi-scid/γ(c)null (NOG) mice were used in all experimentations. We first performed pharmacokinetic studies of the drugs used, either added to food pellets (AZT, TDF, 3TC, RTV) or in a LA formulation that permitted once weekly subcutaneous administration (TMC278: non-nucleoside reverse transcriptase inhibitor, TMC181: protease inhibitor). A combination of 3TC, TDF and TMC278-LA or 3TC, TDF, TMC278-LA and TMC181-LA suppressed the viral load to undetectable levels in 15/19 (79%) and 14/14 (100%) mice, respectively. In successfully treated mice, subsequent monotherapy with TMC278-LA resulted in viral breakthrough; in contrast, the two LA compounds together prevented viral breakthrough. Resistance mutations matched the mutations most commonly observed in HIV patients failing therapy. Importantly, viral rebound after interruption of ART, presence of HIV DNA in successfully treated mice and in vitro reactivation of early HIV transcripts point to an existing latent HIV reservoir.

CONCLUSIONS/SIGNIFICANCE

This report is a unique description of multiple aspects of HIV infection in humanized mice that comprised efficacy testing of various treatment regimens, including LA compounds, resistance mutation analysis as well as viral rebound after treatment interruption. Humanized mice will be highly valuable for exploring the antiviral potency of new compounds or compounds targeting the latent HIV reservoir.

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.

Emergence of minor drug-resistant HIV-1 variants after triple antiretroviral prophylaxis for prevention of vertical HIV-1 transmission

BACKGROUND

WHO-guidelines for prevention of mother-to-child transmission of HIV-1 in resource-limited settings recommend complex maternal antiretroviral prophylaxis comprising antenatal zidovudine (AZT), nevirapine single-dose (NVP-SD) at labor onset and AZT/lamivudine (3TC) during labor and one week postpartum. Data on resistance development selected by this regimen is not available. We therefore analyzed the emergence of minor drug-resistant HIV-1 variants in Tanzanian women following complex prophylaxis.

METHOD

1395 pregnant women were tested for HIV-1 at Kyela District Hospital, Tanzania. 87/202 HIV-positive women started complex prophylaxis. Blood samples were collected before start of prophylaxis, at birth and 1-2, 4-6 and 12-16 weeks postpartum. Allele-specific real-time PCR assays specific for HIV-1 subtypes A, C and D were developed and applied on samples of mothers and their vertically infected infants to quantify key resistance mutations of AZT (K70R/T215Y/T215F), NVP (K103N/Y181C) and 3TC (M184V) at detection limits of <1%.

RESULTS

50/87 HIV-infected women having started complex prophylaxis were eligible for the study. All women took AZT with a median duration of 53 days (IQR 39-64); all women ingested NVP-SD, 86% took 3TC. HIV-1 resistance mutations were detected in 20/50 (40%) women, of which 70% displayed minority species. Variants with AZT-resistance mutations were found in 11/50 (22%), NVP-resistant variants in 9/50 (18%) and 3TC-resistant variants in 4/50 women (8%). Three women harbored resistant HIV-1 against more than one drug. 49/50 infants, including the seven vertically HIV-infected were breastfed, 3/7 infants exhibited drug-resistant virus.

CONCLUSION

Complex prophylaxis resulted in lower levels of NVP-selected resistance as compared to NVP-SD, but AZT-resistant HIV-1 emerged in a substantial proportion of women. Starting AZT in pregnancy week 14 instead of 28 as recommended by the current WHO-guidelines may further increase the frequency of AZT-resistance mutations. Given its impact on HIV-transmission rate and drug-resistance development, HAART for all HIV-positive pregnant women should be considered.

Evolution of HIV-1 genotype in plasma RNA and peripheral blood mononuclear cells proviral DNA after interruption and resumption of antiretroviral therapy

BACKGROUND

Structured antiretroviral therapy interruption (TI) is discouraged because of poorer AIDS and non-AIDS-related outcomes, but is often inevitable in clinical practice. Certain strategies could reduce the emergence of resistance mutations related to TI.

METHODS

A total of 106 HIV-1-infected patients on stable HAART with undetectable plasma viral load were randomized to therapy continuation (n=50) or CD4(+) T-cell-guided TI (n=56). Staggered interruption involved stopping non-nucleoside reverse transcriptase inhibitors (NNRTIs) 7 days before the nucleoside backbone. Genotypic resistance testing (GRT) was performed on proviral DNA from peripheral blood mononuclear cells (PBMCs) at baseline and before each TI, and on plasma RNA after each TI.

RESULTS

At baseline, GRT on PBMCs detected mutations in nine patients and only two major mutations were identified. GRT on plasma samples performed after TIs showed nucleoside reverse transcriptase inhibitors (NRTI), NNRTI and protease inhibitor major resistance associated mutations in 10/56, 3/46 and 1/8 patients receiving these drugs, respectively. Only in two patients had the same mutations been observed in GRT on PBMCs at baseline. Three patients presented virological failure after resumption of therapy, all receiving NNRTIs. In one of them, resistance mutations detected at failure had been also observed previously in GRT on plasma after TI.

CONCLUSIONS

Staggered interruption of NNRTIs 7 days before the nucleoside backbone does not avoid resistance emergence completely, but does not necessarily lead to virological failure after treatment resumption. Plasma HIV-1 RNA genotype after the interruption and the patient's treatment history seem to be more useful than baseline proviral DNA genotype to assess the risk of virological failure after restarting therapy.

Lopinavir/ritonavir single agent therapy as a universal combination antiretroviral therapy stopping strategy: results from the STOP 1 and STOP 2 studies

OBJECTIVES

We designed two different studies to evaluate two different combination antiretroviral therapy (cART) stopping strategies namely a 'staggered stop' approach (STOP 1 study) and a 'protected stop' approach (STOP 2 study) to find the best 'universal stop' strategy.

PATIENTS AND METHODS

Patients who stopped cART for any reason were recruited. In STOP 1, 10 patients on efavirenz continued dual nucleos(t)ide reverse transcriptase inhibitors (NRTIs) for 1 week after discontinuing efavirenz. Efavirenz concentrations were measured weekly for up to 3 weeks. In STOP 2, 20 patients stopped their cART and replaced it with two tablets of lopinavir/ritonavir (Kaletra) (100/50 mg) twice daily for 4 weeks. Lopinavir, efavirenz, nevirapine and tenofovir concentrations were measured weekly for up to 4 weeks. Virological and resistance testing were performed.

RESULTS

In STOP 1 five patients still had efavirenz present (median t(1/2)=148.4 h) 3 weeks after stopping. In STOP 2, 15/20 patients had a viral load (VL) of <40 copies/mL and 3/20 patients had a reduction in VL by 4 weeks. Six patients opted not to stop lopinavir/ritonavir and still had <40 copies/mL at week 8. Week 1-4 median trough lopinavir concentrations were well above the EC(95). Six patients still had detectable concentrations of original cART persisting for >1 week after stopping. No patients developed new resistance mutations.

CONCLUSIONS

Plasma efavirenz concentrations can persist up to 3 weeks after patients stop efavirenz-containing regimens. This suggests a strategy of stopping efavirenz only 1 week before NRTIs may not be long enough for some individuals. The use of lopinavir/ritonavir monotherapy for a 4 week period may be an alternative pharmacologically and virologically effective universal stopping strategy which warrants further investigation.

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.

Limited risk of drug resistance after discontinuation of antiretroviral prophylaxis for the prevention of breastfeeding transmission of HIV

We evaluated 70 HIV-infected pregnant women with CD4⁺ cell count >350 cells per cubic millimeter who received zidovudine, lamivudine, and nevirapine from week 25 of gestation until 6 months after delivery and a 3-week tail of zidovudine and lamivudine at the moment of drug discontinuation. Forty days after the interruption of all drugs resistance mutations were present in 5 of 70 (7.1%) women. Two of them had the same mutation archived in baseline HIV DNA. The other 3 women had, at least once, detectable viral load and presence of mutations during treatment. Overall, the risk of developing resistance mutations in compliant women was low.

Antiretroviral treatment interruption leads to progression of liver fibrosis in HIV-hepatitis C virus co-infection

OBJECTIVE

Despite potential negative consequences, HIV/hepatitis C virus (HCV) co-infected patients may discontinue antiretroviral treatment (ART) for several reasons. We examined the impact of ART interruption on liver fibrosis progression in co-infected adults, using the aspartate aminotransferase-to-platelet ratio index (APRI) as a surrogate marker of liver fibrosis.

METHOD

Data were analyzed from a multisite prospective cohort of 541 HIV-HCV co-infected adults. ART interruption was included as a time-updated variable and defined as the cessation of all antiretrovirals for at least 14 days. The primary endpoint was the development of an APRI score at least 1.5. Time-dependent Cox proportional hazards regression and inverse probability-of-treatment weighting (IPTW) in a marginal structural model were used to evaluate the association of baseline and time-varying covariates with developing significant fibrosis.

RESULTS

Patients were followed for a median of 1.02 years; 10% (n = 53) interrupted ART and 10% (n = 53) developed significant fibrosis. After accounting for potential confounders, including CD4 T-cell count, HIV viral load, baseline APRI score, age and gender, the hazard ratio for ART interruption was 2.52 (95% confidence interval 1.20-5.28). Use of IPTW resulted in a similar effect estimate, suggesting that mediation by time-varying confounders was negligible.

CONCLUSION

ART interruption was associated with an increased risk of fibrosis progression in HIV-HCV co-infection that was only partially accounted for by HIV viral load and CD4 T-cell counts. Our findings suggest that liver disease progression observed in ART-treated co-infected patients is partly due to the consequences of treatment interruptions.

CD4+ T-cell-guided structured treatment interruptions of antiretroviral therapy in HIV disease: projecting beyond clinical trials

BACKGROUND

International trials have shown that CD4+ T-cell-guided structured treatment interruptions (STI) of antiretroviral therapy (ART) lead to worse outcomes than continuous treatment. We simulated continuous ART and STI strategies with higher CD4+ T-cell interruption/reintroduction thresholds than those assessed in actual trials.

METHODS

Using a model of HIV, we simulated cohorts of African adults with different baseline CD4+ T-cell counts (< or = 200; 201-350; and 351-500 cells/microl). We varied ART initiation criteria (immediate; CD4+ T-cell count < 350 cells/microl or > or = 350 cells/microl with severe HIV-related disease; and CD4+ T-cell count <200 cells/microl or > or = 200 cells/microl with severe HIV-related disease), and ART interruption/reintroduction thresholds (350/250; 500/350; and 700/500 cells/microl). First-line therapy was non-nucleoside reverse transcriptase inhibitor (NNRTI)-based and second-line therapy was protease inhibitor (PI)-based.

RESULTS

STI generally reduced life expectancy compared with continuous ART. Life expectancy increased with earlier ART initiation and higher interruption/reintroduction thresholds. STI reduced life expectancy by 48-69 and 11-30 months compared with continuous ART when interruption/reintroduction thresholds were 350/250 and 500/350 cells/microl, depending on ART initiation criteria. When patients interrupted/reintroduced ART at 700/500 cells/microl, life expectancies ranged from 2 months lower to 1 month higher than continuous ART. STI-related life expectancy increased with decreased risk of virological resistance after ART interruptions.

CONCLUSIONS

STI with NNRTI-based regimens was almost always less effective than continuous treatment, regardless of interruption/reintroduction thresholds. The risks associated with STI decrease only if patients start ART earlier, interrupt/reintroduce treatment at very high CD4+ T-cell thresholds (700/500 cells/microl) and use first-line medications with higher resistance barriers, such as PIs.

Associations with virologic treatment failure in adults on antiretroviral therapy in South Africa

OBJECTIVES

Highly active antiretroviral therapy (HAART) has been available in government facilities in the Western Cape Province of South Africa since 2001. We aimed to investigate factors associated with virologic treatment failure in this setting.

DESIGN

Case-control study, matched on facility and on starting date and duration of HAART.

METHODS

Cases and controls were identified from clinic registers from May 2001 to June 2006. Cases were patients who switched to second-line therapy after confirmed virologic failure (2 consecutive viral loads above 1000 copies/mL). Controls were on first-line treatment with viral load <400 copies per milliliter at the time of case incidence.

RESULTS

One hundred thirty cases and 238 controls were selected from 8 clinics (median 16.6 months on HAART, interquartile range: 12.2-24.6). Treatment interruptions [adjusted odds ratio (AOR) 8.6, 95% confidence interval: 3.6 to 20.8], prior nevirapine-based prevention of mother-to-child transmission (PMTCT) treatment (AOR: 9.6, 95% confidence interval: 2.9 to 32.2), a baseline CD4 count less than 50 cells per microliter or from 50-150 cells per microliter (AOR: 6.6, 95% confidence interval: 2.3 to 18.8 and AOR: 5.8, 95% confidence interval: 2.1 to 16.3 compared with a baseline CD4 count of more than 150 cells/microL), and the use of nevirapine in the initial regimen (AOR: 2.5, 95% confidence interval: 1.4 to 4.7) were all independently associated with virologic treatment failure.

CONCLUSIONS

In this setting, nevirapine in the initial HAART regimen or for PMTCT treatment is associated with virologic treatment failure, together with low CD4 count at ART initiation. Earlier initiation of HAART and access to improved triple therapy and PMTCT regimens are priorities for HIV programs in Southern Africa.

Average adherence to boosted protease inhibitor therapy, rather than the pattern of missed doses, as a predictor of HIV RNA replication

Consecutive missed doses may differentially impact the efficacy of antiretroviral therapy associated with the use of a nonnucleoside reverse-transcriptase inhibitor (NNRTI) and a ritonavir-boosted protease inhibitor (PI). In a cohort of 72 subjects receiving a boosted PI, average adherence to dosage was a better predictor of human immunodeficiency virus (HIV) replication than was the duration or frequency of treatment interruption. In contrast with an NNRTI, consecutive missed doses of a boosted PI did not emerge as a major risk factor for HIV replication.

Nonnucleoside reverse transcriptase inhibitor concentrations during treatment interruptions and the emergence of resistance: a substudy of the ISS-PART Trial

Emergence of resistance is one of the drawbacks associated with treatment interruptions (TI), especially when regimens include nonnucleoside reverse transcriptase inhibitors (NNRTIs), because of their long half-life. ISS-PART was a randomized trial comparing a continuous treatment arm with a TI arm in which 136 patients underwent five treatment interruptions, each followed by 3 months of therapy, over 2 years. To minimize the potential risk of developing resistance, patients on NNRTIs were requested, at each TI, to interrupt nevirapine (NVP) or efavirenz (EFV) 3 or 6 days before the other drugs, respectively. To determine if a difference in drug levels existed during TIs between patients with and without resistance we compared NNRTI concentrations in the 12 patients (6 on NVP and 6 on EFV) who developed NNRTI mutations during TIs with those of 20 patients (10 on NVP and 10 on EFV) who retained a wild-type virus. Genotypic resistance and drug concentrations were analyzed on plasma samples collected 15 days after each drug interruption. Overall, EFV was quantifiable in 28% (16/57) and NVP in 22.9% (14/61) of evaluable samples collected during TIs, with no difference between patients with and without mutations. Median EFV or NVP concentrations at each TI were not significantly different between patients with and without mutations. Although the staggered stop strategy was not completely effective in preventing exposure to suboptimal levels, no evident correlation was found between NNRTI concentrations and the emergence of resistance, suggesting that other factors (such as the presence of drug-resistant minority variants) could also play an important role in these patients.

A randomized, controlled, trial of short cycle intermittent compared to continuous antiretroviral therapy for the treatment of HIV infection in Uganda

BACKGROUND

Short cycle treatment interruption could reduce toxicity and drug costs and contribute to further expansion of antiretroviral therapy (ART) programs.

METHODS

A 72 week, non-inferiority trial enrolled one hundred forty six HIV positive persons receiving ART (CD4+ cell count > or =125 cells/mm(3) and HIV RNA plasma levels <50 copies/ml) in one of three arms: continuous, 7 days on/7 days off and 5 days on/2 days off treatment. Primary endpoint was ART treatment failure determined by plasma HIV RNA level, CD4+ cell count decrease, death attributed to study participation, or opportunistic infection.

RESULTS

Following enrollment of 32 participants, the 7 days on/7 days off arm was closed because of a failure rate of 31%. Six of 52 (11.5%) participants in the 5 days on/2 days off arm failed. Five had virologic failure and one participant had immunologic failure. Eleven of 51 (21.6%) participants in the continuous treatment arm failed. Nine had virologic failure with 1 death (lactic acidosis) and 1 clinical failure (extra-pulmonary TB). The upper 97.5% confidence boundary for the difference between the percent of non-failures in the 5 days on/2 days off arm (88.5% non-failure) compared to continuous treatment (78.4% non failure) was 4.8% which is well within the preset non-inferiority margin of 15%. No significant difference was found in time to failure in the 2 study arms (p = 0.39).

CONCLUSIONS

Short cycle 5 days on/2 days off intermittent ART was at least as effective as continuous therapy.

TRIAL REGISTRATION

ClinicalTrials.gov NCT00339456.