Initial virological and immunologic response to highly active antiretroviral therapy predicts long-term clinical outcome

Machine learning to predict virological failure among HIV patients on antiretroviral therapy in the University of Gondar Comprehensive and Specialized Hospital, in Amhara Region, Ethiopia, 2022

BACKGROUND

Treatment with effective antiretroviral therapy (ART) reduces viral load as well as HIV-related morbidity and mortality in HIV-positive patients. Despite the expanded availability of antiretroviral therapy around the world, virological failure remains a serious problem for HIV-positive patients. Thus, Machine learning predictive algorithms have the potential to improve the quality of care and predict the needs of HIV patients by analyzing huge amounts of data, and enhancing prediction capabilities. This study used different machine learning classification algorithms to predict the features that cause virological failure in HIV-positive patients.

METHOD

An institution-based secondary data was used to conduct patients who were on antiretroviral therapy at the University of Gondar Comprehensive and Specialized Hospital from January 2020 to May 2022. Patients' data were extracted from the electronic database using a structured checklist and imported into Python version three software for data pre-processing and analysis. Then, seven supervised classification machine-learning algorithms for model development were trained. The performances of the predictive models were evaluated using accuracy, sensitivity, specificity, precision, f1-score, and AUC. Association rule mining was used to generate the best rule for the association between independent features and the target feature.

RESULT

Out of 5264 study participants, 1893 (35.06%) males and 3371 (64.04%) females were included. The random forest classifier (sensitivity = 1.00, precision = 0.987, f1-score = 0.993, AUC = 0.9989) outperformed in predicting virological failure among all selected classifiers. Random forest feature importance and association rules identified the top eight predictors (Male, younger age, longer duration on ART, not taking CPT, not taking TPT, secondary educational status, TDF-3TC-EFV, and low CD4 counts) of virological failure based on the importance ranking, and the CD-4 count was recognized as the most important predictor feature.

CONCLUSION

The random forest classifier outperformed in predicting and identifying the relevant predictors of virological failure. The results of this study could be very helpful to health professionals in determining the optimal virological outcome.

Review on fluorinated nucleoside/non-nucleoside FDA-approved antiviral drugs

FDA-approved antiviral agents represent an important class that has attracted attention in recent years to combat current and future threats of viral pandemics. Fluorine ameliorates the electronic, lipophilic and steric problems of drugs. Additionally, fluorine can prolong drug activity and improve metabolic stability, thereby, modifying their pharmacodynamic and pharmacokinetic character. Herein, we summarized the fluorinated FDA-approved antiviral agents, dealing with biological aspects, mechanisms of action, and synthetic pathways.

Recent Advances Towards Treatment of HIV: Synthesis and SAR Studies

In the present study, authors want to encourage the research exertions through structureactivity relationship for the identification of effective molecules for the treatment of Human immunodeficiency virus because nowadays AIDS is considered as one of the main causes of death in human beings. A diversity of biological resources has been searched and developed for the treatment of HIV but unfortunately, until now, no medicine is found to be fully effective and safe for the cure of patients. Human immunodeficiency virus is a type of lentivirus which causes the infection of HIV and once it enters the human body, it stays for a longer period of time triggering immunodeficiency syndrome. For searching and developing new potent and effective anti-HIV molecules, medicinal chemists have engaged in countless targets with the structure-activity relationship (SAR) of molecules and on this basis, many antiretroviral therapies have been developed to cure HIV infection. Most of these new searched molecules have been found to be clinically active against various types of AIDS patient and auxiliary research in this area may lead to better treatment in the near future. This article encompasses and highlights the recent advancement of innumerable inhibitors laterally through synthetic, semi-synthetic and structure-activity relationship approaches.

Antiretroviral therapy adherence among treatment-naive HIV-infected patients

OBJECTIVE

To determine the incidence of antiretroviral therapy (ART) adherence among treatment-naive HIV-infected patients and to evaluate the impact of single-tablet regimen (STR) on ART adherence among this population.

DESIGN

Retrospective cohort study.

METHODS

We used a nationally representative sample of IQVIA LRx Lifelink individual level pharmacy claims database during 2011-2016, and defined adult patients with index date (first complete ART regimen prescription fill date) after 30 June 2011 as treatment naïve. We estimated ART adherence, measured as the proportion of days covered during 1 year following the index date. We conducted multivariable analysis to identify the factors associated with optimum adherence (≥90% proportion of days covered). We also compared adherence between patients prescribed STR and multiple-tablet regimens among those prescribed integrase strand transfer inhibitor-based or nonnucleoside reverse transcriptase inhibitor-based regimens.

RESULTS

Overall 42.9% of the patients were optimally adherent. Adherence was significantly lower among blacks, Hispanics and patients in low-income communities. Adjusting for the covariates, patients on STR had higher incidence of optimum adherence compared with those on multiple-tablet regimens among patients on integrase strand transfer inhibitor-based regimens [49 vs. 24%, relative risk, 2.16 (95% confidence interval: 1.96-2.26)], but no significant difference was observed among those on nonnucleoside reverse transcriptase inhibitor-based regimen [45 vs. 45%, relative risk, 1.12 (95% confidence interval: 0.99-1.26)].

CONCLUSION

Low ART adherence observed among treatment-naive patients in this nationally representative study suggests the need for public health interventions to improve adherence among this population.

Effectiveness of antiretroviral therapy in the single-tablet regimen era

OBJECTIVE

To evaluate the effectiveness of antiretroviral therapy and the associated factors according to the type of regimen used: Single Tablet Regimen or Multiple Tablet Regimen.

METHODS

Prospective cohort of 440 patients (male, 74.3%, median age, 36 years old) who initiated antiretroviral therapy between Jan/14 and Dec/15 at a referral service in Belo Horizonte. Efficacy was defined as viral suppression (viral load, VL < 50 copies/ml) and evaluated after six and twelve months of treatment. Sociodemographic, clinical and behavioral data were collected from clinical charts and from Information Systems. Multivariate analysis of overall effectiveness was performed by logistic regression.

RESULTS

Most patients initiated Multiple Tablet Regimen antiretroviral therapy (n = 255, 58%). At six months, overall viral suppression was 74.6%, being higher among patients who used Single Tablet Regimen (80.6%, p = 0.04). At twelve months, 83.2% of patients reached viral suppression, with no difference between groups (p = 0.93). Factors independently associated with viral suppression at six and twelve months varied, being negatively associated with effectiveness: VL ≥ 100,000 copies/ml, symptoms of AIDS, longer interval time between diagnosis and initiation of antiretroviral therapy, antiretroviral switching, smoking or current illicit drugs usage (p < 0.05). Factors positively associated with viral suppression included adherence to antiretroviral therapy and category of risk/exposure of men who have sex with men (p < 0.05). Reaching viral suppression at six months was the main predictor of effectiveness at one year (OR = 8.96 and p < 0.01).

CONCLUSIONS

Viral suppression was high and better results were achieved for patients who used Single Tablet Regimen regimens at six months. Clinical, behavioral, and antiretroviral therapy -related factors influence viral suppression and highlight the need for interventions to increase early diagnosis and initiation of antiretroviral therapy, patient’s adherence, and to reduce illicit drugs and cigarette smoking in this population.

Determinants of virological failure among patients on highly active antiretroviral therapy in University of Gondar Referral Hospital, Northwest Ethiopia: a case-control study

BACKGROUND

Viral load monitoring is used as an important biomarker for diagnosing treatment failure in patients with HIV infection/AIDS. Ethiopia has started targeted viral load monitoring. However, factors leading to virological failure are not well understood and studied. Thus, the aim of this study was to identify the determinants of virological failure among HIV-infected patients on highly active antiretroviral therapy at the University of Gondar Referral Hospital, Northwest Ethiopia.

METHODS

A case-control study was conducted from May to June 2015. Cases were subjects who had already experienced virological failure; controls were those without virological failure. Data were extracted from 153 cases and 153 controls through chart review. A multivariate logistic regression analysis was carried out to identify factors associated with virological failure, and variables with a p-value <0.05 were considered statistically significant.

RESULTS

In this study, higher odds of virological failure was observed among patients aged <35 years (adjusted odds ratio [AOR] =2.52, 95% CI: 1.33, 4.77), who had had CD4+ count <200 cells/mm³ (AOR=9.03, 95% CI: 4.40, 18.50), showed poor adherence to antiretroviral therapy (ART) (AOR=15.80, 95% CI: 6.90, 36.50), and had taken ART for longer durations of 25-47 months (AOR=3.00, 95% CI: 1.10, 8.40) and ≥48 months (AOR=6.70, 95% CI: 2.70, 16.60).

CONCLUSION

This study showed that patients aged <35 years and with recent low CD4 count, poor adherence to treatment, and longer exposure to ART were positively and significantly associated with virological treatment failure. Therefore, evidence-based intervention should be implemented to improve adherence to ART, which in turn helps to boost immunity (CD4) and suppresses viral replication and load. Moreover, attention should be given to younger patients who have had ART for longer periods.

Natural Products as Anti-HIV Agents and Role in HIV-Associated Neurocognitive Disorders (HAND): A Brief Overview

As the threat of Human Immunodeficiency Virus (HIV)/Acquired Immunodeficiency Syndrome (AIDS) persists to rise, effective drug treatments are required to treat the infected people. Even though combination antiretroviral therapy (cART) provides stable viral suppression, it is not devoid of undesirable side effects, especially in persons undergoing long-term treatment. The present therapy finds its limitations in the emergence of multidrug resistance and accordingly finding new drugs and novel targets is the need of the hour to treat the infected persons and further to attack HIV reservoirs in the body like brain, lymph nodes to achieve the ultimate goal of complete eradication of HIV and AIDS. Natural products such as plant-originated compounds and plant extracts have enormous potential to become drug leads with anti-HIV and neuroprotective activity. Accordingly, many research groups are exploring the biodiversity of the plant kingdom to find new and better anti-HIV drugs with novel mechanisms of action and for HIV-associated neurocognitive disorders (HAND). The basic challenge that still persists is to develop viral replication-targeted therapy using novel anti-HIV compounds with new mode of action, accepted toxicity and less resistance profile. Against this backdrop, the World Health Organization (WHO) suggested the need to evaluate ethno-medicines for the management of HIV/AIDS. Consequently, there is need to evaluate traditional medicine, particularly medicinal plants and other natural products that may yield effective and affordable therapeutic agents. Although there are a good number of reports on traditional uses of plants to treat various diseases, knowledge of herbal remedies used to manage HIV/AIDS and HAND are scanty, vague and not well documented. In this review, plant substances showing a promising action that is anti-HIV and HAND will be explored along with what they interact. Since some plant substances are also known to modulate several cellular factors which are also involved in the replication of HIV and hence their role as potential candidates will be discussed. HIV/AIDS being an exceptional epidemic, demands an exceptional approach and that forms very much focus for the current review.

Cell cycle checkpoints and pathogenesis of HIV-1 infection: a brief overview

To understand HIV pathogenesis or development is no simple undertaking and neither is the cell cycle which is highly complex that requires the coordination of multiple events and machinery. It is interesting that these two processes are interrelated, intersect and interact as HIV-1 infection results in cell cycle arrest at the G2 phase which is accompanied by massive CD4+ T cell death. For its own benefit, in an impressive manner and with the overabundance of tactics, HIV maneuvers DNA damage responses and cell cycle check points for viral replication at different stages from infection, to latency and to pathogenesis. Although the cell cycle is the most critical aspect involved in both viral and cellular replication, in this review, our main focus is on recent developments, including our own observations in the field of cell cycle proteins, checkpoints and strategies utilized by the viruses to manipulate these pathways to promote their own replication and survival. We will also discuss the emerging concept of targeting the replication initiation machinery for HIV therapy.

Polymeric anti-HIV therapeutics

The scope of this review is to highlight the application of polymer therapeutics in an effort to curb the transmission and infection of the human immunodeficiency virus (HIV). Following a description of the HIV life cycle, the use of approved antiretroviral drugs that inhibit critical steps in the HIV infection process is highlighted. After that, a comprehensive overview of the structure and inhibitory properties of polymeric anti-HIV therapeutic agents is presented. This overview will include inhibitors based on polysaccharides, synthetic polymers, dendritic polymers, polymer conjugates as well as polymeric DC-SIGN antagonists. The review will conclude with a section that discusses the applications of polymers and polymer conjugates as systemic and topical anti-HIV therapeutics.

Fluorine Substituted 1,2,4-Triazinones as Potential Anti-HIV-1 and CDK2 Inhibitors

Fluorine substituted 1,2,4-triazinones have been synthesized via alkylation, amination, and/or oxidation of 6-(2-amino-5-fluorophenyl)-3-thioxo-3,4-dihydro-1,2,4-triazin-5(2H)-one1and 4-fluoro-N-(4-fluoro-2-(5-oxo-3-thioxo-2,3,4,5-tetrahydro-1,2,4-triazin-6-yl)phenyl)benzamide5as possible anti-HIV-1 and CDK2 inhibitors. Alkylation on positions 2 and 4 in 1,2,4-triazinone gave compounds6–8. Further modification was performed by selective alkylation and amination on position 3 to form compounds9–15. However oxidation of5yielded compounds16–18. Structures of the target compounds have been established by spectral analysis data. Five compounds (5, 11, 14, 16, and17) have shown very good anti-HIV activity in MT-4 cells. Similarly, five compounds (1, 3, and14–16) have exhibited very significant CDK2 inhibition activity. Compounds14and16were found to have dual anti-HIV and anticancer activities.

Past, present and future molecular diagnosis and characterization of human immunodeficiency virus infections

Substantive and significant advances have been made in the last two decades in the characterization of human immunodeficiency virus (HIV) infections using molecular techniques. These advances include the use of real-time measurements, isothermal amplification, the inclusion of internal quality assurance protocols, device miniaturization and the automation of specimen processing. The result has been a significant increase in the availability of results to a high level of accuracy and quality. Molecular assays are currently widely used for diagnostics, antiretroviral monitoring and drug resistance characterization in developed countries. Simple and cost-effective point-of-care versions are also being vigorously developed with the eventual goal of providing timely healthcare services to patients residing in remote areas and those in resource-constrained countries. In this review, we discuss the evolution of these molecular technologies, not only in the context of the virus, but also in the context of tests focused on human genomics and transcriptomics.

Beneficial effects of a switch to a Lopinavir/ritonavir-containing regimen for patients with partial or no immune reconstitution with highly active antiretroviral therapy despite complete viral suppression

The purpose of this study was to determine if switching to an Lopinavir/ritonavir (LPV/r)-containing regimen resulted in greater immune reconstitution in patients with immunologic failure despite complete viral suppression with highly active antiretroviral therapy (HAART). Twenty patients with partial or no immune response to HAART despite viral suppression were enrolled. Ten were randomized to stay on their current regimen and 10 were randomized to LPV/r plus their current NRTI backbone. T cell subsets, ex vivo apoptosis, and the percent of circulating cells with detectable intracellular HIV-1 RNA were measured. The mean increase in CD4(+) count at 6 months was 116/mm(3) (172-288) for the LPV/r-containing arm versus 32/mm(3) (264-296) for continuation regimens (p = 0.03). The number of patients with an increase ≥50 cells/mm(3) was also greater in the LPV/r arm (7/9 versus 2/10, p = 0.01). This paralleled a decrease in ex vivo apoptosis of naive CD4(+) T cells at 6 months (21.7-11.0% for the LPV/r arm versus 17.3-18.9% for the continuation arm, p = 0.04) and memory cells (21.1-14.1% for LPV/r versus 20.2-17.9% for continuation arm, NSS). Switching patients to an LPV/r-containing regimen improved CD4(+) counts in patients with prior immunologic failure, and this may be due to an effect of LPV/r on apoptosis.

Cumulative viral load and virologic decay patterns after antiretroviral therapy in HIV-infected subjects influence CD4 recovery and AIDS

BACKGROUND

The impact of viral load (VL) decay and cumulative VL on CD4 recovery and AIDS after highly-active antiretroviral therapy (HAART) is unknown.

METHODS AND FINDINGS

Three virologic kinetic parameters (first year and overall exponential VL decay constants, and first year VL slope) and cumulative VL during HAART were estimated for 2,278 patients who initiated HAART in the U.S. Military HIV Natural History Study. CD4 and VL trajectories were computed using linear and nonlinear Generalized Estimating Equations models. Multivariate Poisson and linear regression models were used to determine associations of VL parameters with CD4 recovery, adjusted for factors known to correlate with immune recovery. Cumulative VL higher than the sample median was independently associated with an increased risk of AIDS (relative risk 2.38, 95% confidence interval 1.56-3.62, p<0.001). Among patients with VL suppression, first year VL decay and slope were independent predictors of early CD4 recovery (p = 0.001) and overall gain (p<0.05). Despite VL suppression, those with slow decay during the first year of HAART as well as during the entire therapy period (overall), in general, gained less CD4 cells compared to the other subjects (133 vs. 195.4 cells/µL; p = 0.001) even after adjusting for potential confounders.

CONCLUSIONS

In a cohort with free access to healthcare, independent of established predictors of AIDS and CD4 recovery during HAART, cumulative VL and virologic decay patterns were associated with AIDS and distinct aspects of CD4 reconstitution.

Basic PK/PD principles of drug effects in circular/proliferative systems for disease modelling

Disease progression modelling can provide information about the time course and outcome of pharmacological intervention on the disease. The basic PK/PD principles of proliferative and circular systems within the context of modelling disease progression and the effect of treatment thereupon are illustrated with the goal to better understand/predict eventual clinical outcome. Circular/proliferative systems can be very complex. To facilitate the understanding of how a dosing regimen can be defined in such systems we have shown the derivation of a system parameter named the Reproduction Minimum Inhibitory Concentration (RMIC) which represents the critical concentration at which the system switches from growth to extinction. The RMIC depends on two parameters (RMIC = (R₀ − 1) × IC₅₀): the basic reproductive ratio (R₀) a fundamental parameter of the circular/proliferative system that represents the number of offspring produced by one replicating species during its lifespan, and the IC₅₀, the potency of the drug to inhibit the proliferation of the system. The RMIC is constant for a given system and a given drug and represents the lowest concentration that needs to be achieved for eradication of the system. When exposure is higher than the RMIC, success can be expected in the long term. Time varying inhibition of replicating species proliferation is a natural consequence of the time varying inhibitor drug concentrations and when combined with the dynamics of the circular/proliferative system makes it difficult to predict the eventual outcome. Time varying inhibition of proliferative/circular systems can be handled by calculating the equivalent effective constant concentration (ECC), the constant plasma concentration that would give rise to the average inhibition at steady state. When ECC is higher than the RMIC, eradication of the system can be expected. In addition, it is shown that scenarios that have the same steady state ECC whatever the dose, dosage schedule or PK parameters have also the same average R₀ in the presence of the inhibitor (i.e. R_0-INH) and therefore lead to the same outcome. This allows predicting equivalent active doses and dosing schedules in circular and proliferative systems when the IC₅₀ and pharmacokinetic characteristics of the drugs are known. The results from the simulations performed demonstrate that, for a given system (defined by its RMIC), treatment success depends mainly on the pharmacokinetic characteristics of the drug and the dosing schedule.

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.

Immunological rebound after initiation of highly active antiretroviral therapy in treatment-naive patients

Large clinical trials have repeatedly proven the effectiveness of highly active antiretroviral therapy (HAART) in achieving virological suppression; however, subsequent increases in CD4 cell counts (i.e., immunological rebound) do not always follow. Thus, it remains unclear to what extent persons living with HIV/AIDS may expect significant increases in CD4 cell count upon HAART initiation, particularly outside of the highly structured environment of a clinical trial. We analyzed the patterns of CD4 and plasma viral load (PVL) change in 170 HIV-infected individuals who were ART naive and initiated HAART between 1997 and 2003. Immunological success (>50 CD4 cells/mm(3) increase) was evaluated using Kaplan-Meier survival analysis and Cox proportional hazard models. Of individuals, 80% experienced a confirmed CD4 cell count increase of >50 cells/mm(3) after HAART initiation. Multivariate analysis showed that patients with pre-HAART PVL >or=100,000 copies/ml were more likely to achieve immunological success when compared with patients with baseline PVL <10,000 copies/ml, suggesting that individuals with the highest HIV viral load levels may benefit the most from HAART initiation. Future studies of immunological rebound are warranted to further define and characterize immune responses to HAART in diverse populations in order to optimize guidelines for initiation of treatment and assessment of successful responses.

HIV-1 coreceptor usage and CXCR4-specific viral load predict clinical disease progression during combination antiretroviral therapy

BACKGROUND

Although combination antiretroviral therapy (cART) dramatically reduces rates of AIDS and death, a minority of patients experience clinical disease progression during treatment.

OBJECTIVE

To investigate whether detection of CXCR4(X4)-specific strains or quantification of X4-specific HIV-1 load predict clinical outcome.

METHODS

From the Swiss HIV Cohort Study, 96 participants who initiated cART yet subsequently progressed to AIDS or death were compared with 84 contemporaneous, treated nonprogressors. A sensitive heteroduplex tracking assay was developed to quantify plasma X4 and CCR5 variants and resolve HIV-1 load into coreceptor-specific components. Measurements were analyzed as cofactors of progression in multivariable Cox models adjusted for concurrent CD4 cell count and total viral load, applying inverse probability weights to adjust for sampling bias.

RESULTS

Patients with X4 variants at baseline displayed reduced CD4 cell responses compared with those without X4 strains (40 versus 82 cells/microl; P = 0.012). The adjusted multivariable hazard ratio (HR) for clinical progression was 4.8 [95% confidence interval (CI) 2.3-10.0] for those demonstrating X4 strains at baseline. The X4-specific HIV-1 load was a similarly independent predictor, with HR values of 3.7 (95% CI, 1.2-11.3) and 5.9 (95% CI, 2.2-15.0) for baseline loads of 2.2-4.3 and > 4.3 log10 copies/ml, respectively, compared with < 2.2 log10 copies/ml.

CONCLUSIONS

HIV-1 coreceptor usage and X4-specific viral loads strongly predicted disease progression during cART, independent of and in addition to CD4 cell count or total viral load. Detection and quantification of X4 strains promise to be clinically useful biomarkers to guide patient management and study HIV-1 pathogenesis.

Adherence to enfuvirtide and its impact on treatment efficacy

High adherence rates to antiretroviral (ARV) therapy are associated with increased durability of viral suppression and decreased rates of drug resistance. The requirement of twice-daily subcutaneous self-administration of enfuvirtide (ENF) has raised concerns about adherence. This study assesses adherence to ENF and an optimized background (OB) of ARVs and its impact on virological and immunological responses during the TORO trials. Eighty-eight percent of patients in the OB arm reported > or = 85% adherence versus 87% of patients in the ENF + OB arm. Higher overall adherence was associated with improved virological and immunological response in both treatment arms at 48 weeks. In patients with > or = 85% adherence, 33% of patients in the ENF + OB arm achieved HIV-1 RNA < 400 copies/ml, versus 13% in the OB arm (p < 0.0001). Similarly, patients with > or = 85% adherence in the ENF + OB arm achieved a mean increase in CD4 cell count of 104 cells/mm(3) compared with 58 cells/mm(3) for patients in the OB arm (p < 0.001). None of the demographic factors explored (age, gender, race) or baseline characteristics (CD4 count, viral load, or baseline sensitivity score) was significant in predicting adherence to ENF when analyzed by multiple regression. Importantly, a history of intravenous drug use (IDU) was not associated with a significant decrease in adherence (mean adherence for IDU 96% versus mean adherence for non-IDU 96%; p = 0.825). Adherence was high in patients receiving the self-injectable ARV enfuvirtide. In addition, the inclusion of ENF did not negatively impact adherence to the ARV regimen as a whole.

Rapid selection of drug-resistant HIV-1 during the first months of suppressive ART in treatment-naive patients

OBJECTIVE

Efficient antiretroviral therapy (ART) of HIV-1 infection reduces the viral load to undetectable levels and restores the immune system. However, therapy failure appears in a substantial fraction of patients and is mostly associated with the appearance of drug-resistant viruses. It is still not clear when the drug pressure leads to the earliest selection and appearance of drug-resistant HIV-1 populations. In this study, we wanted to determine whether drug-resistant viruses are already selected during viral decline within the first months of ART.

DESIGN AND METHODS

Fifteen mostly chronically HIV-1 infected patients were included. None had received ART prior to this study. The selection of three key resistance mutations, L90M (protease), K103N and M184V (reverse transcriptase), were measured by allele-specific real-time PCR allowing us to track minority quasispecies with a discriminative power of 0.01-0.2%.

RESULTS

Drug-resistant HIV-1 variants were found in 7/15 patients (46.7%) prior to ART. Rapid selection of drug resistance was detected in six patients (40%) independent of the presence of drug-resistant HIV-1 prior to ART. The risk for the selection of drug resistant viruses was correlated with the time until viral load became undetectable (P = 0.02). Besides the proportional increment of drug-resistant viruses, we observed in two patients a quantitative increase of this virus population while the total viral load decreased.

CONCLUSIONS

Drug-resistant viruses can be selected and replicate even in the first weeks of suppressive ART, thus, intensification of ART during the initial treatment period should be considered and further evaluated in clinical studies.

Incidence of Tuberculosis among HIV-infected patients receiving highly active antiretroviral therapy in Europe and North America

BACKGROUND

We obtained estimates of the incidence of tuberculosis (TB) among patients receiving HAART and identified determinants of the incidence.

METHODS

We analyzed the incidence of TB during the first 3 years after initiation of HAART among 17,142 treatment-naive, AIDS-free persons starting HAART who were enrolled in 12 cohorts from Europe and North America. We used univariable and multivariable Poisson regression models to identify factors associated with the incidence.

RESULTS

During the first 3 years (36,906 person-years), 173 patients developed TB (incidence, 4.69 cases per 1000 person-years). In multivariable analysis, the incidence rate was lower for men who have sex with men, compared with injection drug users (relative rate, 2.46; 95% confidence interval [CI], 1.51-4.01), heterosexuals (relative rate, 2.42; 95% CI, 1.64-3.59), those with other suspected modes of transmission (relative rate, 1.66; 95% CI, 0.91-3.06), and those with a higher CD4+ count at the time of HAART initiation (relative rate per log2 cells/microL, 0.87; 95% CI, 0.84-0.91). During 28,846 person-years of follow-up after the first 6 months of HAART, 88 patients developed TB (incidence, 3.1 cases per 1000 person-years of follow-up). In multivariable analyses, a low baseline CD4+ count (relative rate per log2 cells/microL, 0.89; 95% CI, 0.83-0.96), 6-month CD4+ count (relative rate per log2 cells/microL, 0.90; 95% CI, 0.81-0.99), and a 6-month HIV RNA level >400 copies/mL (relative rate, 2.21; 95% CI, 1.33-3.67) were significantly associated with the risk of acquiring TB after 6 months of HAART.

CONCLUSION

The level of immunodeficiency at which HAART is initiated and the response to HAART are important determinants of the risk of TB. However, this risk remains appreciable even among those with a good response to HAART, suggesting that other interventions may be needed to control the TB epidemic in the HIV-infected population.

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

Early prediction of suboptimal viral response to highly active antiretroviral therapy (HAART) is vital to prevent early development of drug resistance. We used logistic regression to predict the odds of achieving virologic suppression (<50 copies/mL) after 24 weeks of HAART in 656 antiretroviral-naive patients starting HAART at the J.W. Goethe University, Chelsea and Westminster, and Royal Free Hospitals according to their week 4 viral load. Therapy changes involving the switch of a single antiretroviral were assumed to have occurred for toxicity reasons and ignored. Because complete regimen changes or additions of new antiretrovirals could be due to virologic failure, patients were counted as virological failures at week 24. Three hundred sixty (84%) of 430 patients with viral loads of <1000 copies/mL, 106 (61%) of 175 with viral loads between 1001 and 10,000 copies/mL, 11 (37%) of 30 with viral loads between 10,001 and 100,000 copies/mL, and 5 (24%) of 21 with viral loads of >100,000 copies/mL at week 4 subsequently attained virologic suppression at 24 weeks. The odds of attaining virologic suppression at 24 weeks was 65% lower for every 1-log higher viral load at week 4 (odds ratio, 0.35; 95% confidence interval, 0.27-0.45). The proportion of patients with an undetectable viral load at 24 weeks among those who have not attained a viral load of <1000 copies/mL by 4 weeks is quite low. We suggest that this group of patients should be particularly closely monitored.

Effectiveness of Antiretroviral Therapy Among Patients Who Attend Public HIV Clinics in Rio de Janeiro, Brazil

OBJECTIVE

Brazil provides antiretroviral therapy (ART) to HIV-infected persons free of charge. The objective of this study was to investigate factors associated with ART failure in patients receiving free ART in public clinics in Brazil.

METHODS

This is a cross-sectional study of adults taking ART for 6 to 24 months in 5 public clinics in Rio de Janeiro. Patients were interviewed and their charts were reviewed. The following definitions of response to therapy at 6 months were used: virologic responders (VR), > or =1 log reduction in plasma viral load (VL); immunologic responders (IR), increase of > or = 50 CD4 cells/mL; complete responders (CR), both VR and IR; and nonresponders (NR), neither VR nor IR.

RESULTS

Of 211 patients enrolled, 173 (82%) were VR, IR, or CR and 38 (18%) were NR. Of the responders, 28 (13%) were IR, 32 (15%) were VR, and 113 (53%) were CR. In multivariate analysis, factors associated with NR were less than 80% adherence (OR = 8.6; 95% CI, 2.9-25.7), baseline CD4 count (OR = 0.5 per 50 cells/mL; 95% CI, 0.2-1.1), interval between starting ART and first VL/CD4 testing (OR = 1.4 for each month; 95% CI, 1.1-1.8), opportunistic disease after starting ART (OR = 6.8; 95% CI, 1.4-34.0), inability to read prescription (OR = 3.9; 95% CI, 1.4-10.9), not believing physician is knowledgeable about HIV (OR = 4.0; 95% CI, 1.1-15.0), not having a friend with HIV (OR = 6.1; 95% CI, 1.7-21.8), believing ART will make him/her ill (OR = 5.6; 95% CI, 1.7-18.8), and believing ART will delay HIV progression (OR = 0.001; 95% CI, 0.0-0.2).

CONCLUSION

The proportion of patients responding to ART in Brazil was similar to reports from developed countries, suggesting that ART can be used successfully in developing countries. Variables related to adherence, knowledge, and perceptions about ART were associated with a lack of response to ART. These findings have important implications for developing nations that are considering increased access to ART.

Effectiveness of Antiretroviral Therapy after Protease Inhibitor Failure: An Analytic Overview

To examine effectiveness of subsequent antiretroviral therapy (ART), studies published during the period of 1 January 1997 through 31 May 2003 involving patients who had failed a protease inhibitor (PI)-containing regimen and were switched to another regimen were reviewed. Twelve studies describing 1197 patients were analyzed. A total of 38% of patients had human immunodeficiency virus (HIV) RNA levels of <500 copies/mL at 24 weeks. After adjustment for baseline HIV RNA level, the rate of virologic suppression ranged from 16% for patients switching drugs within previously failed classes to 54% for nonnucleoside reverse-transcriptase inhibitor (NNRTI)-naive patients switched to boosted PI- and NNRTI-containing regimens. ART regimens in patients who failed a PI-containing regimen provided virologic suppression only in a few patients. The best response was seen in NNRTI-naive patients receiving NNRTI- and boosted PI-containing regimens. New approaches are needed to achieve better suppression in pretreated HIV-infected patients.

Enfuvirtide: the first therapy to inhibit the entry of HIV-1 into host CD4 lymphocytes

Highly active antiretroviral therapy (HAART) based on combinations of drugs that target key enzymes in the life-cycle of human immunodeficiency virus (HIV) has considerably reduced morbidity and mortality from HIV infection since its introduction in the mid-1990s. However, the growing problem of the emergence of HIV strains that are resistant not only to individual drugs, but to whole drug classes, means that agents with new mechanisms of action are needed. Here, we describe the discovery and development of enfuvirtide (Fuzeon), the first drug to inhibit the entry of HIV-1 into host cells.

Impact of early versus late adherence to highly active antiretroviral therapy on immuno-virological response: a 3-year follow-up study

OBJECTIVE

To assess the impact of different patterns of adherence to highly active antiretroviral therapy (HAART), in particular, the relative impact of early and late adherence, on long-term immuno-virological response in HIV-infected individuals started on a protease inhibitor-containing regimen.

DESIGN

Clinical, immuno-virological and self-reported adherence data were collected at 4 (M4), 12 (M12), 20 (M20), 28 (M28) and 36 (M36) months after HAART initiation in the French APROCO cohort.

METHODS

A standardized self-administered questionnaire classified patients as non-adherent, moderately or highly adherent at each visit. Stable viral suppression at both M28 to M36, and a CD4 cell increase > 200 between M0 and M36 were used as outcome measures.

RESULTS

Of the 582 patients followed regularly through M36, 360 patients had complete adherence data. Although 59.2% were highly adherent at M4, only 25.8% maintained consistent high adherence throughout the follow-up. High adherence at M4 was independently associated with both stable viral suppression at M28-M36 [OR (95% CI): 2.8 (1.4-5.5)] and a CD4 cell increase > 200 during the same period [OR (95% CI): 3.9 (1.7-9.7)]. However, 'moderately adherent' patients between M12 and M36 had the same likelihood [OR (95% CI): 1.9 (1.1-3.2)] as patients who were always high adherent [OR (95% CI): 1.9 (1.1-3.2)] of achieving stable viral load suppression, relative to those who reported non-adherence episodes.

CONCLUSION

Optimizing adherence in the early months of treatment is crucial to ensure long-term immuno-virological high adherence during follow-up have a less negative impact. Priority should be given to interventions aimed to improve adherence in the early months of HAART.

Prognostic value of changes in CD4 count and HIV RNA during the first six months on highly active antiretroviral therapy in chronic human immunodeficiency virus infection

The aim of this study was to evaluate the prognostic value of changes in CD4 counts and human immunodeficiency virus (HIV) RNA following 6 months of highly active antiretroviral therapy (HAART) in chronic HIV-1 infection. 148 treatment-naive patients treated with 2 nucleoside analogue reverse transcriptase inhibitors (NRTIs) + at least 1 protease inhibitor or non-NRTI for at least 180 d were included. Mean follow-up time after 6 months on HAART was 758 d. The patients were divided into 2 groups based on the increase in CD4 count (deltaCD4) from therapy initiation: groups A (n = 37, deltaCD4 < 0.052 x 10(9)/l) and B (n = 111, deltaCD4 > or = 0.052 x 10(9)/l). Patients were also stratified according to achievement of HIV RNA < 400 copies/ml (n = 122) or > or = 400 copies/ml (n = 26). Endpoints were the occurrence of subsequent HIV-related disease (CDC category B or C) or death after 6 months on HAART. Subjects in group A had an increased risk of HIV-related disease compared with group B when adjusted for CD4 count at initiation of therapy [adjusted risk ratio (RR) 2.62, 95% confidence interval (95% CI) 1.07-6.40]. Viral load > or = copies/ml versus reaching viral suppression < 400 copies/ml was associated with an increased risk of HIV-related disease only in patients with deltaCD4 < 0.052 x 10(9)/l (RR 4.20, 95% CI 1.05-16.9). Thus, this study indicates that patients with no or a small increase in CD4 counts after 6 months of HAART and low CD4 levels at initiation of therapy have an increased risk of HIV-related disease.

Prognostic importance of initial response in HIV-1 infected patients starting potent antiretroviral therapy: analysis of prospective studies

BACKGROUND

We examined whether the initial virological and immunological response to highly active antiretroviral treatment (HAART) is prognostic in patients with HIV-1 who start HAART.

METHODS

We analysed 13 cohort studies from Europe and North America including 9323 adult treatment-naive patients who were starting HAART with a combination of at least three drugs. We modelled clinical progression from month 6 after starting HAART, taking into account CD4 count and HIV-1 RNA measured at baseline and 6 months.

FINDINGS

During 13408 years of follow-up 152 patients died and 874 developed AIDS or died. Compared with patients who had a 6-month CD4 count of fewer than 25 cells/microL, adjusted hazard ratios for AIDS or death were 0.55 (95%CI 0.32-0.96) for 25-49 cells/microL, 0.62 (0.40-0.96) for 50-99 cells/microL, 0.42 (0.28-0.64) for 100-199 cells/microL, 0.25 (0.16-0.38) for 200-349 cells/microL, and 0.18 (0.11-0.29) for 350 or more cells/microL at 6 months. Compared with patients who had a 6-month HIV-1 RNA of 100000 copies/mL or greater, adjusted hazard ratios for AIDS or death were 0.59 (0.41-0.86) for 10000-99999 copies/mL, 0.42 (0.29-0.61) for 500-9999 copies/mL, and 0.29 (0.21-0.39) for 6-month HIV-1 RNA of 500 copies/mL or fewer. Baseline CD4 and HIV-1 RNA were not associated with progression after controlling for 6-month concentrations. The probability of progression at 3 years ranged from 2.4% in the patients in the lowest-risk stratum to 83% in patients in the highest-risk stratum.

INTERPRETATION

At 6 months after starting HAART, the current CD4 cell count and viral load, but not values at baseline, are strongly associated with subsequent disease progression. Our findings should inform guidelines on when to modify HAART.

Alternative therapies: a common practice among men and women living with HIV

This study examined the prevalence and factors associated with alternative therapy use in an ethnically diverse, gender-balanced sample of persons living with HIV/AIDS. More than two thirds (67%) of the participants who were taking HIV-related medications were also taking an alternative supplement. Half of the sample (50%) reported that they took one or more multivitamins, 17% reported using mineral supplements, 12% reported using Chinese herbs, and 12% reported using botanicals. Substantial proportions of the sample also reported using acupuncture (31%), massage (23%), and meditation (28%) to specifically treat HIV-related symptoms. Women were four times more likely to use alternative therapies than men. Also, Caucasians were nearly four times more likely to use alternative treatments compared to other ethnic groups. The results of this study indicate a strong need to assess individual patients' use of alternative treatment approaches as well as to further investigate their efficacy among HIV-positive patients.

Adherence to HAART regimens

The problem of inadequate adherence to prescribed highly active antiretroviral therapy (HAART) drug regimens to treat HIV infection and AIDS is ubiquitous. Adherence can be inadequate despite both provider and patient understanding of the consequences of nonadherence. Successful long-term treatment of HIV/AIDS requires at least 95% adherence to HAART in order to prevent emergence of drug-resistant HIV variants that lead to regimen failure and limit options for future therapy. Despite the prevalence of inadequate adherence, many patients succeed, and HAART has transformed HIV infection into a chronic illness increasingly managed in primary care. The barriers to adherence observed in HIV treatment resemble barriers to the successful treatment of other chronic diseases: regimen complexity, side effects resulting in poor tolerability, patient lifestyle factors, and patient-provider relationships. Treatment of HIV infection has shown that patient-provider collaboration can result in the selection of a lifestyle-tailored regimen characterized by convenient dosing, low pill burden, and tolerable side effects that enhances adherence, effectiveness, and the patient's willingness to remain on anti-HIV therapy long term. This review focuses on the current understanding of adherence reporting, improvement of adherence, and, hence, improvement of treatment outcomes in HIV infection and AIDS.

Virologic and Immunologic Response to Highly Active Antiretroviral Therapy

Highly active antiretroviral therapy (HAART) delays clinical progression to AIDS by suppressing viral replication, allowing the immune system to reconstitute. These virologic and immunologic consequences do not occur uniformly among HAART users; markers of HIV disease stage at the time of HAART initiation are critical determinants of the progression while under HAART. In this paper, we review studies describing the heterogeneous virologic and immunologic progression following the initiation of HAART, and update findings obtained in the Multicenter AIDS Cohort Study that show that CD4 cell count and history of antiretroviral therapy at the time of initiation are independent determinants of response.