Use of viral load measured after 4 weeks of highly active antiretroviral therapy to predict virologic outcome at 24 weeks for HIV-1-positive individuals

A randomized, placebo-controlled, dose-escalation phase I/II multicenter trial of low-dose cidofovir for BK polyomavirus nephropathy

BACKGROUND

BK polyomavirus-associated nephropathy (BKPyVAN) is an important cause of allograft dysfunction and failure in kidney transplant recipients (KTRs) and there are no proven effective treatments. Case reports and in vitro data support the potential activity of cidofovir against BK polyomavirus (BKPyV).

METHODS

We report the results of a phase I/II, double-blind, placebo-controlled randomized dose-escalation trial of cidofovir in KTRs with biopsy-confirmed BKPyVAN and estimated glomerular filtration rate ≥30 mL/min. Intravenous cidofovir (0.25 mg/kg/dose or 0.5 mg/kg/dose) or placebo was administered on days 0, 7, 21, and 35, with final follow-up through day 49.

RESULTS

The trial was prematurely discontinued due to slow accrual after 22 KTRs had completed the study. Cidofovir was safe and tolerated at the doses and duration studied. The proportion of subjects with any adverse event (AE) was similar between groups (9/14 [64%] in the combined cidofovir dose groups and 6/8 [75%] in the placebo group); 84% of AEs were mild. BKPyV DNAemia reduction by day 49 was similar between groups (>1 log10 reduction in (2/9 [22.2%] of 0.25 mg/kg group, 1/5 [20%] of 0.5 mg/kg group, and 2/8 [25%] of placebo group).

CONCLUSIONS

These preliminary results indicate that low-dose cidofovir was safe and tolerated but had no significant BKPyV-specific antiviral effect in KTRs with BKPyVAN.

HIV treatment outcomes following antiretroviral therapy initiation and monitoring: A workplace program in Papua, Indonesia

Background

Papua Province, Indonesia is experiencing an on-going epidemic of Human Immunodeficiency Virus (HIV) infection, with an estimated 9-fold greater prevalence than the overall national rate. This study reviewed the treatment outcomes of an HIV-infected cohort on Antiretroviral Therapy (ART) and the predictors in terms of immunological recovery and virological response.

Methods

ART-naïve individuals in a workplace HIV program in southern Papua were retrospectively analyzed. Patients were assessed at 6, 12 and 36 months after ART initiation for treatment outcomes, and risk factors for virological suppression (viral load (VL) <1,000 copies/ml), poor immune response (CD4 <200 cells/mm³) and immunological failure (CD4 <100 cells/ mm³) after at least 6 months on ART, using a longitudinal Generalized Estimating Equations multivariate model.

Results

Assessment of 105 patients were included in the final analysis with a median age of 34 years, 88% male, median baseline CD4 236 cells/ mm³, and VL 179,000 copies/ml. There were 74, 73, and 39 patients at 6, 12, and 36 months follow-up, respectively, with 5 deaths over the entire period. For the three observation periods, 68, 80, and 75% of patents achieved virological suppression, poor immune responders decreased from 15, 16 to 10%, whilst 15, 16, 10% met the immunological failure criteria, respectively. Using multivariate analysis, the independent predictor for viral suppression at 12 and 36 months was ≥1 log decrease in VL at 6 months (OR 19.25, p<0.001). Higher baseline CD4 was significantly correlated with better immunological outcomes, and lower likelihood of experiencing immunological failure (p <0.001).

Conclusion

Virological response at six months after beginning ART is the strongest predictor of viral suppression at 12 and 36 months, and may help in identifying patients needing additional adherence therapy support. Higher baseline CD4 positively affects the immunological outcomes of patients. The findings indicate HIV control programs should prioritize the availability of VL testing and begin ART regardless of CD4 counts in infected patients.

Nurturing the Continuum of HIV Testing, Treatment and Prevention Matrix Cascade in Reducing HIV Transmission

Background

Despite the shift in antiretroviral therapy (ARVs) eligibility cascade from CD4 ≤ 200 to CD4 ≤ 350 to CD4 ≤ 500 mm³, HIV related morbidity and mortality continue to escalate annually, as do HIV infections. The new paradigm of treatment for all HIV positives individual irrespective of CD4 count may significantly reduce HIV and related illnesses. The author assumes that all HIV infected partners should be eligible for HIV treatment and care, irrespective of CD4 count. A second assumption is that high risk HIV negative partners have free access to continuum of HIV pre-exposure prophylaxis (PrEP), post exposure prophylaxis (PEP) and other prevention packages.

Methods

A literature review search was used to extract evidence-based ARVs-HIV treatment and prevention interventions among HIV positives and high risk partners respectively. Only articles published in English and indexed in journal nuclei were used for the study. The information was used to nurture understanding of HIV treatment and prevention approaches as well as HIV incidence multiplier effect among HIV serodiscordant partners. The imputed HIV incident reference was assumed at 1.2 per 100 person-years (2). This was based on the imputation that retention in care, adherence and other predetermined factors are functions of an effective health care delivery system.

Result

The model showed a reduced HIV transmission from 1.2 per 100 person-years to 1.032 per 100 person-years in 6 months. The average threshold period of HIV suppressed partners on ARVs to an undetectable level. The combined multiplier protective-effect probability of transmitting HIV from HIV positive partners on ARVs-suppressed viremic load to HIV negative partners on PrEP/PEP-prevention was detected at 86%

Conclusion

The model showed a significant reduction in HIV incidence. Placing serodiscordant sexual partners in HIV treatment and prevention plays a significant role in reducing and controlling HIV infection. Therefore, the policy of enrolling all HIV positives irrespective of CD4 count on ARVs and high risk partners on prevention if adopted and sustained may underpin reduction and control of HIV genotype and HIV related morbidity, mortality and opportunistic infections.

HIV viral suppression in Oman: Encouraging progress toward achieving the United Nations 'third 90'

OBJECTIVE

To assess the impact of capacity-building interventions introduced by the Oman National AIDS Programme on the quality of HIV care in the country.

METHODS

HIV viral load (VL) suppression and loss to follow-up (LTFU) rates were calculated for the period before (in December 2015; n=1098) and after (in June 2017; n=1185) the introduction of the interventions: training, support, and care pathway development. Three HIV VL cuts-offs at last measurement in the year of interest were used to define VL suppression.

RESULTS

In the intention-to-treat (ITT) analysis, rates of VL <200 copies/ml and <1000 copies/ml increased from 51.9% in 2015 to 65.5% in 2017 (relative risk (RR) 1.26, 95% confidence interval (CI) 1.17-1.36) and from 58.1% in 2015 to 70.9% in 2017 (RR 1.22, 95% CI 1.14-1.30), respectively; p<0.0001 for both. Similarly, in the on-treatment analysis, rates of VL <200 copies/ml and <1000copies/ml increased from 64.2% in 2015 to 76.9% in 2017 (RR 1.20, 95% CI 1.12-1.28) and from 71.9% in 2015 to 83.2% in 2017 (RR 1.16, 95% CI 1.10-1.22), respectively. Fewer patients were LTFU in 2017 than in 2015 (14.7% (157/1061) vs. 19.2% (188/981); RR 0.77, 95% CI 0.64-0.94).

CONCLUSIONS

Achieving the UNAIDS target of 90% of HIV patients on treatment having VL suppression by 2020 is feasible in Oman.

Predicting virological decay in patients starting combination antiretroviral therapy

OBJECTIVE

Model trajectories of viral load measurements from time of starting combination antiretroviral therapy (cART), and use the model to predict whether patients will achieve suppressed viral load (≤200 copies/ml) within 6-months of starting cART.

DESIGN

Prospective cohort study including HIV-positive adults (UK Collaborative HIV Cohort Study).

METHODS

Eligible patients were antiretroviral naive and started cART after 1997. Random effects models were used to estimate viral load trends. Patients were randomly selected to form a validation dataset with those remaining used to fit the model. We evaluated predictions of suppression using indices of diagnostic test performance.

RESULTS

Of 9562 eligible patients 6435 were used to fit the model and 3127 for validation. Mean log10 viral load trajectories declined rapidly during the first 2 weeks post-cART, moderately between 2 weeks and 3 months, and more slowly thereafter. Higher pretreatment viral load predicted steeper declines, whereas older age, white ethnicity, and boosted protease inhibitor/non-nucleoside reverse transcriptase inhibitors based cART-regimen predicted a steeper decline from 3 months onwards. Specificity of predictions and the diagnostic odds ratio substantially improved when predictions were based on viral load measurements up to the 4-month visit compared with the 2 or 3-month visits. Diagnostic performance improved when suppression was defined by two consecutive suppressed viral loads compared with one.

CONCLUSIONS

Viral load measurements can be used to predict if a patient will be suppressed by 6-month post-cART. Graphical presentations of this information could help clinicians decide the optimum time to switch treatment regimen during the first months of cART.

HIV viral load: a concept analysis and critique

In this article, we examine the concept of HIV viral load and how it has evolved over time (1995-2013) in the field of HIV/AIDS. Although the term viral load is used extensively in this field, few efforts have been directed toward the conceptualization of HIV viral load, which is often left unquestioned, undertheorized, and portrayed as a neutral and objective laboratory value that has remained relatively stable over time--with the exception of progressive advancements in technology, techniques, and sensitivity. The purpose of this article is to apply the evolutionary concept analysis method developed by Rodgers (1989, 2000a) to the concept of HIV viral load. To set the stage, we establish the need for a concept analysis of HIV viral load and provide an overview of the evolutionary view. Then, drawing on the steps proposed by Rodgers (2000a), we outline the process of data collection, management, and analysis. We then offer an in-depth discussion of the findings (attributes, antecedents, and consequences) informed by Wuest's (2000) critical approach to concept analysis. We conclude by highlighting the implications of this analysis for clinical practice, research, and theory.

Prevalence of Depressive Symptoms Amongst Highly Active Antiretroviral Therapy (HAART) Patients in AIDSRelief Uganda

There is limited data on the prevalence of depression in HIV and AIDS patients in Sub-Saharan Africa and little resources have been allocated to address this issue. Depression affects patient adherence to treatment and predisposes patients to resistance which poses a public health threat. It also affects quality of life and productivity of patients. From August 2008 to March 2009, 731 patient adherence surveys were administered to assess disease, treatment knowledge and services received. The primary variable of interest was patients' level of depressive symptoms score, constructed using factor analysis from five survey questions relating to: sadness, need to be alone, hopelessness and confusion and was categorized as no depressive symptoms (score 0), low depressive symptoms (score 1-2), moderate depressive symptoms (score 3-4) and high depressive symptoms (score 5-10). Majority of the patients on highly active antiretroviral therapy (HAART) (59%) were found to have depressive symptoms and this was more among women than men (66% vs 43%). There was some association of depressive symptoms with non-disclosure (70% of those who had not disclosed had depressive symptoms compared to 53% among those who had disclosed). There is a high prevalence of depressive symptoms among adult patients on HAART. There is need for in-depth evaluation to find out the root causes of depressive symptoms among HAART patients in AIDSRelief clinics. There is need to integrate mental health management in HIV care and treatment as well as training the existing health workers on mental health management.

The impact of HIV-1 reverse transcriptase polymorphisms on responses to first-line nonnucleoside reverse transcriptase inhibitor-based therapy in HIV-1-infected adults

OBJECTIVE

HIV-1 genetic variability may influence antiretroviral therapy (ART) outcomes. The study aim was to determine the impact of polymorphisms in regions known to harbor major nonnucleoside reverse transcriptase inhibitor (NNRTI) resistance mutations (codons 90-108, 135-138, 179-190, 225-348) on virologic responses to first-line NNRTI-based ART.

METHODS

Reverse transcriptase sequences from ART-naive individuals who commenced efavirenz (EFV) or nevirapine (NVP) with at least two nucleos(t)ide reverse transcriptase inhibitors (NRTIs) without major drug resistance mutations were analyzed. The impact of polymorphisms on week 4 viral load decrease and time to virologic failure was measured over a median 97 weeks.

RESULTS

Among 4528 patients, most were infected with HIV-1 subtype B (67%) and commenced EFV-based ART (84%). Overall, 2598 (57%) had at least one polymorphism, most frequently at codons 90, 98, 101, 103, 106, 135, 138, 179, and 238. Virologic failure rates were increased in patients with two (n = 597) or more than two (n = 72) polymorphisms [adjusted hazard ratio 1.43; 95% confidence interval (CI) 1.07-1.92; P = 0.016]. Polymorphisms associated with virologic failure occurred at codons 90 (mostly V90I), 98 (mostly A98S), and 103 (mostly K103R), with adjusted hazard ratios of 1.78 (1.15-2.73; P = 0.009), 1.55 (1.16-2.08; P = 0.003), and 1.75 (1.00-3.05: P = 0.049), respectively. Polymorphisms at codon 179, especially V179D/E/T, predicted reduced week 4 responses (P = 0.001) but not virologic failure.

CONCLUSION

The occurrence of multiple polymorphisms, though uncommon, was associated with a small increase in the risk of NNRTI treatment failure; significant effects were seen with polymorphisms at codon 90, 98, and 103. The mechanisms underlying the slower suppression seen with V179D/E/T deserve further investigation.

Mean cost of a first combination antiretroviral therapy in HIV-infected patients in France, and determinants of expensive drugs prescription

To estimate the cost of the first combination antiretroviral drug therapy (cART) in HIV-infected patients and to determine factors associated with expensive prescriptions, 1698 patients starting cART between September 2002 and September 2007 were selected from the Dat'AIDS cohort. A multivariate linear regression model was used to assess associations between the cost of first cART and patient characteristics, clinical centre and cART adequacy. At cART initiation, the median age was 39 years, median CD4 count was 223 cells/mm3, median viral load (VL) was 5.2 log copies/mL and 18.3% presented with AIDS. cART was concordant with the French guidelines in 88.7%. The mean cost of cART varied from €26.69/day/person in 2002-2003 to €32.23 in 2006-2007 ( P < 0.0001), cost was associated with previous AIDS diagnosis (€31.83/day/person) versus (29.49; P < 0.0001), baseline VL > 5 log copies/mL (€30.99/day/person) versus (28.33; P < 0.0001) and centre. cART regimen not concordant with guidelines were more expensive (€38.31/day/person) versus (29.07; P < 0.0001). After adjusting for the year of initiation, the previous AIDS diagnosis, VL and recommended cART regimen, differences were still found between centres (from €27.81/day/person) to (33.12; P < 0.0001). Cost should be considered when choosing a first cART regimen, especially when considering clinically equivalent regimens.

A highly intensified ART regimen induces long-term viral suppression and restriction of the viral reservoir in a simian AIDS model

Stably suppressed viremia during ART is essential for establishing reliable simian models for HIV/AIDS. We tested the efficacy of a multidrug ART (highly intensified ART) in a wide range of viremic conditions (10³-10⁷) viral RNA copies/mL) in SIVmac251-infected rhesus macaques, and its impact on the viral reservoir. Eleven macaques in the pre-AIDS stage of the disease were treated with a multidrug combination (highly intensified ART) consisting of two nucleosidic/nucleotidic reverse transcriptase inhibitors (emtricitabine and tenofovir), an integrase inhibitor (raltegravir), a protease inhibitor (ritonavir-boosted darunavir) and the CCR5 blocker maraviroc. All animals stably displayed viral loads below the limit of detection of the assay (i.e. <40 RNA copies/mL) after starting highly intensified ART. By increasing the sensitivity of the assay to 3 RNA copies/mL, viral load was still below the limit of detection in all subjects tested. Importantly, viral DNA resulted below the assay detection limit (<2 copies of DNA/5*10⁵ cells) in PBMCs and rectal biopsies of all animals at the end of the follow-up, and in lymph node biopsies from the majority of the study subjects. Moreover, highly intensified ART decreased central/transitional memory, effector memory and activated (HLA-DR⁺) effector memory CD4⁺ T-cells in vivo, in line with the role of these subsets as the main cell subpopulations harbouring the virus. Finally, treatment with highly intensified ART at viral load rebound following suspension of a previous anti-reservoir therapy eventually improved the spontaneous containment of viral load following suspension of the second therapeutic cycle, thus leading to a persistent suppression of viremia in the absence of ART. In conclusion, we show, for the first time, complete suppression of viral load by highly intensified ART and a likely associated restriction of the viral reservoir in the macaque AIDS model, making it a useful platform for testing potential cures for AIDS.

Defining treatment failure in resource-rich settings

PURPOSE OF REVIEW

To define treatment failure in resource-rich settings; summarizing current guidelines, assays, the significance of detectable viremia, and definitions of treatment failure in clinical and research settings.

RECENT FINDINGS

The goal of treatment should be full viral suppression, even in highly treatment-experienced patients.

SUMMARY

Treatment failure is defined as repeated HIV RNA values above the lower limit of detection of a sensitive assay (usually 50 copies/ml). This criterion is based on evidence that the maximum clinical benefit of antiretroviral therapy is derived by keeping the viral load as low as possible. Full viral suppression should be achievable in all patients, both treatment-naïve and experienced. Transient, low-detectable viremia ('blips') may not predict virologic breakthrough. However, consecutive or higher-level transient viremia is associated with risk of treatment failure. Defining failure by a confirmed HIV RNA more than 50 copies/ml is the most conservative approach, but the use of such low limits of detection in clinical trials may lead to a high false-positive 'failure' rate, thus a definition of 200 copies/ml may be preferable. Variation in clinical trial endpoint definitions creates a challenge for comparing results between studies. For example, using a composite endpoint to define treatment failure may result in a high proportion of 'failures' that are not related to poor virologic response.

British HIV Association (BHIVA) national cohort outcomes audit of patients commencing antiretrovirals from naïve

OBJECTIVES

The aim of this work was to audit the extent to which routine HIV care in the UK conforms with British HIV Association (BHIVA) guidelines and specifically the proportion of patients starting highly active antiretroviral therapy (HAART) who achieve the outcome of virological suppression below 50 HIV-1 RNA copies/mL within 6 months.

METHODS

A prospective cohort review of adults with HIV infection who started antiretroviral therapy (ART) for the first time between April and September 2006 was carried out using structured questionnaire forms.

RESULTS

A total of 1170 adults from 122 clinical sites participated in the review. Of these patients, 699 (59.7%) started ART at CD4 counts <200 cells/microL and 193 (16.5%) had not been tested for HIV drug resistance. Excluding patients with valid reasons for stopping short-term ART, 795 (73.5%) of 1081 patients had an undetectable viral load (VL) at follow-up. Detectable VL was strongly associated with pretreatment CD4 count below 50 cells/microL and pretreatment VL above 100 000 copies/mL, and was not associated with clinic location or case load. About a quarter of patients did not have a VL measurement during the first 6 weeks after starting ART.

CONCLUSIONS

The majority of patients who initiated ART at sites participating in this UK national audit were managed within the BHIVA guidelines and achieved virological suppression below 50 copies/mL around 6 months after commencing treatment. Poor VL outcomes were associated with very low CD4 cell count and/or high VL at baseline but not with clinic case load or location. There is an urgent need to diagnose patients at an earlier stage of their HIV disease.

Risk factors for poor virological outcome at 12 months in a workplace-based antiretroviral therapy programme in South Africa: a cohort study

Background

Reasons for the variation in reported treatment outcomes from antiretroviral therapy (ART) programmes in developing countries are not clearly defined.

Methods

Among ART-naïve individuals in a workplace ART programme in South Africa we determined virological outcomes at 12 months, and risk factors for suboptimal virological outcome, defined as plasma HIV-1 viral load >= 400 copies/ml.

Results

Among 1760 individuals starting ART before July 2004, 1172 were in follow-up at 12 months of whom 953 (81%) had a viral load measurement (median age 41 yrs, 96% male, median baseline CD4 count 156 × 10⁶/l). 71% (681/953) had viral load < 400 copies/ml at 12 months. In a multivariable analysis, independent predictors of suboptimal virological outcome at 12 months were <1 log decrease in viral load at six weeks (odds ratio [OR] 4.71, 95% confidence interval [CI] 2.56–8.68), viral load at baseline (OR 3.63 [95% CI 1.88–7.00] and OR 3.54 [95% CI 1.79–7.00] for 10,001–100,000 and >100,000 compared to <= 10,000 copies/ml, respectively), adherence at six weeks (OR 3.50 [95% CI 1.92–6.35]), WHO stage (OR 2.08 [95% CI 1.28–3.34] and OR 2.03 [95% CI 1.14–3.62] for stage 3 and 4 compared to stage 1–2, respectively) and site of ART delivery. Site of delivery remained an independent risk factor even after adjustment for individual level factors. At 6 weeks, of 719 patients with self-reported adherence and viral load, 72 (10%) reported 100% adherence but had <1 log decrease in viral load; conversely, 60 (8%) reported <100% adherence but had >= 1 log decrease in viral load.

Conclusion

Virological response at six weeks after ART start was the strongest predictor of suboptimal virological outcome at 12 months, and may identify individuals who need interventions such as additional adherence support. Self reported adherence was less strongly associated but identified different patients compared with viral load at 6 weeks. Site of delivery had an important influence on virological outcomes; factors at the health system level which influence outcome need further investigation to guide development of effective ART programmes.

Peptide bioinformatics: peptide classification using peptide machines

Peptides scanned from whole protein sequences are the core information for many peptide bioinformatics research such as functional site prediction, protein structure identification, and protein function recognition. In these applications, we normally need to assign a peptide to one of the given categories using a computer model. They are therefore referred to as peptide classification applications. Among various machine learning approaches, including neural networks, peptide machines have demonstrated excellent performance in many applications. This chapter discusses the basic concepts of peptide classification, commonly used feature extraction methods, three peptide machines, and some important issues in peptide classification.

National review of first treatment change after starting highly active antiretroviral therapy in antiretroviral-naïve patients

OBJECTIVES

The aim of the study was to explore the factors surrounding modification of the first antiretroviral (ARV) regimen where drug switch occurred 3 months or more after initiation. Reference was made to the British HIV Association (BHIVA) guidelines on HIV management.

METHODS

A case note and questionnaire-based audit was carried out.

RESULTS

Toxicity was the single most important reason for ARV change and was the only, or a contributory, cause in over half the patients. Virological failure, adherence issues, requirement for treatment simplification, and patient request were other significant reasons cited. In one-third of those with virological failure, six or more months had elapsed between first detection and the time of switching to a new ARV regimen.

CONCLUSIONS

This audit demonstrated broad adherence to the BHIVA guidelines, although the long time before switching ARVs in the setting of virological failure was of some concern, particularly given the continuing and significant occurrence of primary ARV resistance in the UK.

Predictors of long-term viral failure among ugandan children and adults treated with antiretroviral therapy

BACKGROUND

HIV RNA viral load testing is costly and is generally unavailable in resource-limited settings. We identified predictors of viral failure and documented genotypic mutations in a subset of patients with viral failure after 12 months on antiretroviral therapy (ART).

METHODS

From April 2004 to June 2005, consecutive treatment-naive patients beginning ART at a university clinic in Uganda were enrolled. Clinical information, CD4 cell count, and HIV RNA level were collected at baseline and every 3 to 6 months. Independent predictors of viral failure were identified using multivariate logistic regression. Genotypic drug resistance for 8 patients with viral failure at 12 months was measured at baseline and at 6 and 12 months.

RESULTS

Five hundred twenty-six adults and 250 children (0 to 18 years of age) were started on first-line ART regimens and followed for 12 months. Outcomes could not be assessed in 13% of patients (79 died and 21 were withdrawn). Children were almost twice as likely to have viral failure compared with adults (26% vs. 14%; P = 0.0001). In adults, the sole independent predictor of viral failure was treatment with stavudine (d4T)/lamivudine (3TC)/nevirapine (NVP) versus zidovudine (ZDV)/3TC/efavirenz (EFV) (odds ratio [OR] = 2.59, 95% confidence interval [CI]: 1.20 to 5.59). In children, independent predictors of viral failure included male gender (OR = 2.44, 95% CI: 1.20 to 4.93), baseline CD4% <5 (OR = 2.69, 95% CI: 1.28 to 5.63), and treatment with d4T/3TC/NVP versus ZDV/3TC/EFV (OR = 2.46, 95% CI: 1.23 to 4.90). All 8 patients with viral breakthrough and genotypic drug resistance results had nonnucleoside reverse transcriptase inhibitor (NNRTI)- and 3TC-associated mutations.

CONCLUSIONS

These data demonstrate the effectiveness of ART in a low-resource setting. Children and patients of all ages taking the d4T/3TC/NVP regimen were more likely to have viral failure. Our data suggest that viral failure occurring 6 months or more after the start of ART regimens commonly used in Uganda is likely to be associated with NNRTI- and 3TC-resistant virus.

HIV-1 load quantitation: a 17-year perspective

During the past decade and a half, quantitation of plasma-associated human immunodeficiency virus type 1 (HIV-1) RNA level, or HIV-1 load, has been validated in clinical practice and clinical trials as an important surrogate marker of HIV-1 disease progression and of the potency and durability of antiretroviral regimens. This review highlights some of the history, accomplishments, and impact of Tom Merigan's laboratory on the use of HIV-1 load as a marker, as well as on updating technologies for determining HIV-1 load, their performance, interpretation of the results, and their use in clinical practice.

Week-12 response to therapy as a predictor of week 24, 48, and 96 outcome in patients receiving the HIV fusion inhibitor enfuvirtide in the T-20 versus Optimized Regimen Only (TORO) trials

BACKGROUND

Early virological response to antiretroviral therapy is predictive of long-term treatment outcome in therapy-naive patients. In treatment-experienced patients, such correlations are less well defined, because initial responses may be less pronounced and transient because of accumulated cross-resistance to prior therapies. Our objectives were to explore how the virological and immunological status of treatment-experienced patients at an early time point (week 12) during enfuvirtide-based therapy predicted their responses at weeks 24, 48, and 96 in the T-20 versus Optimized Regimen Only (TORO) trials.

METHODS

Post hoc, modified, on-treatment and intent-to-treat analyses were performed to determine whether the relationship between virological and immunological outcomes at weeks 24, 48, and 96 were predicted by the patients' week-12 responses to therapy.

RESULTS

Using a modified on-treatment analysis for patients who, by week 12, achieved a decrease in their HIV-1 RNA load of > or =1 log10 copies/mL, 39.2% (95% CI, 33.6%-44.8%) and 59.5% (95% CI, 53.8%-65.1%) achieved a viral load of <50 copies/mL or <400 copies/mL at week 96, respectively, compared with 1.3% (95% CI, 0%-3.8%) and 2.6% (95% CI, 0%-6.1%) of patients, respectively, who did not achieve an early virological response. Using the same modified on-treatment analysis method for patients who, at week 12, achieved a CD4 cell count increase of > or =50 cells/mm3, 87.2% (95% CI, 82.6-91.8) maintained or improved this response through week 96, compared with 56.6% (95% CI, 47.5-65.8) of patients who did not achieve this early categorical immunological response.

CONCLUSION

Enfuvirtide-based treatment regimens are associated with a rapid and durable response. Week-12 virological and immunological responses to treatment with enfuvirtide are predictive of subsequent outcomes in triple-class treatment-experienced patients.

A new model to monitor the virological efficacy of antiretroviral treatment in resource-poor countries

Monitoring the efficacy of antiretroviral treatment in developing countries is difficult because these countries have few laboratory facilities to test viral load and drug resistance. Those that exist are faced with a shortage of trained staff, unreliable electricity supply, and costly reagents. Not only that, but most HIV patients in resource-poor countries do not have access to such testing. We propose a new model for monitoring antiretroviral treatment in resource-limited settings that uses patients' clinical and treatment history, adherence to treatment, and laboratory indices such as haemoglobin level and total lymphocyte count to identify virological treatment failure, and offers patients future treatment options. We believe that this model can make an accurate diagnosis of treatment failure in most patients. However, operational research is needed to assess whether this strategy works in practice.