Three- vs four-drug antiretroviral regimens for the initial treatment of HIV-1 infection: a randomized controlled trial

Efavirenz: a decade of clinical experience in the treatment of HIV

Efavirenz, a non-nucleoside reverse transcriptase inhibitor, has been an important component of the treatment of HIV infection for 10 years and has contributed significantly to the evolution of highly active antiretroviral therapy (HAART). The efficacy of efavirenz has been established in numerous randomized trials and observational studies in HAART-naive patients, including those with advanced infection. In the ACTG A5142 study, efavirenz showed greater virological efficacy than the boosted protease inhibitor (PI), lopinavir. Efavirenz is more effective as a third agent than unboosted PIs or the nucleoside analogue abacavir. Some, but not all, studies have suggested that efavirenz (added to two nucleoside reverse transcriptase inhibitors) is more effective than nevirapine. Virological and immunological responses achieved with efavirenz-based HAART have been maintained for 7 years. Dosing convenience predicts adherence, and studies have demonstrated that patients can be switched from PI-based therapy to simplified, once-daily efavirenz-based regimens without losing virological control. The one-pill, once-daily formulation of efavirenz plus tenofovir and emtricitabine offers a particular advantage in this regard. Efavirenz also retains a role after failure of a first PI-based regimen. Efavirenz is generally well tolerated: rash and neuropsychiatric disturbances are the most notable adverse events. Neuropsychiatric disturbances generally develop early in treatment and they tend to resolve with continued administration, but they are persistent and troubling in a minority of patients. Efavirenz has less effect on plasma lipid profiles than some boosted PIs. Lipodystrophy can occur under treatment with efavirenz but it may be reduced if the concurrent use of thymidine analogues is avoided. Efavirenz resistance mutations (especially K103N) can be selected during long-term treatment, underscoring the importance of good adherence. Recent data have confirmed that efavirenz is a cost-effective option for first-line HAART. In light of these features, efavirenz retains a key role in HIV treatment strategies and is the first-line agent recommended in some guidelines.

Long-term impact of efavirenz on neuropsychological performance and symptoms in HIV-infected individuals (ACTG 5097s)

BACKGROUND

Efavirenz (EFV) is an antiretroviral (ARV) drug associated with neuropsychological effects. Limited data describing the long-term impact of EFV-based regimens on neuropsychological performance over more than 3 years are available.

METHODS

We enrolled a subset of participants from a large initially EFV placebo-controlled trial of therapies for HIV subjects naïve to ARV treatment (A5095). Clinical follow-up continued for 184 weeks of study. Subjects were assessed with brief neuropsychological testing, a symptom questionnaire of EFV-associated symptoms, the Pittsburgh Sleep Index, Center for Epidemiologic Studies-Depression Scale, and an anxiety rating interview.

RESULTS

Over 184 weeks on EFV, the median NPZ3 score in 86 evaluable patients improved from baseline by +0.5 (p < .01); all components improved, although higher EFV levels were associated with slightly lower responses. Overall symptom scores did not change, while EFV-associated CNS symptoms increased (p = .01). Median change of bad dream sleep scores and anxiety increased from the baseline while global depression score decreased.

CONCLUSIONS

In participants who continued EFV-based regimens, neuropsychological performance improvement from baseline was maintained over 3 years. EFV-based treatment was generally well tolerated, but small increases from baseline in EFV-associated symptoms, bad dreams, and anxiety were detected.

Comorbidities and challenges affecting African Americans with HIV infection

The significant disparities in health outcomes that exist among racial minorities in the United States are clearly evident in the HIV epidemic. HIV disproportionately affects minorities, African Americans in particular. Current treatment of HIV/AIDS is complicated by medical problems such as hepatitis, diabetes and dyslipidemia, which also disproportionately affect African Americans and can significantly impact the complexity of clinical care. In addition, untreated psychological problems such as depression and societal barriers to adequate medical care may decrease treatment adherence and increase HIV-related morbidity and mortality among African Americans. Consideration of these issues by healthcare providers is necessary to optimize care and improve treatment outcomes for African Americans with HIV infection.

Sociodemographic factors predict early discontinuation of HIV non-nucleoside reverse transcriptase inhibitors and protease inhibitors

BACKGROUND/OBJECTIVE

HIV infection has a devastating impact on individual and public health, and affects populations disproportionately. Treatment with antiretroviral therapy (ART) saves lives, but long-term adherence to ART is critical to its success. We performed an observational cohort study to determine the influence of race, sex and other sociodemographic factors on early ART discontinuations among HIV-infected persons.

METHODS

TennCare-enrolled adults of black or white non-Hispanic race beginning ART with either a non-nucleoside reverse transcriptase inhibitor (NNRTI) or protease inhibitor (PI) between 1996-2003 (N=3654) were assessed for early discontinuation. A subgroup of discontinuations was validated using the primary medical record.

RESULTS

Blacks were more likely than whites to discontinue NNRTIs (37 vs. 28%; P=0.003) and PIs (36 vs. 25%; P < or = 0.001). In multivariable models adjusting for race, sex, age, early HIV-related medical encounter, urban residence and TennCare enrollment category, black race, female sex and younger age were independent predictors of discontinuation among those starting PIs. Among persons starting NNRTIs, black race, younger age and a disability-based enrollment category predicted early drug discontinuation, but female sex did not.

CONCLUSIONS

Our results suggest that sociodemographic factors were associated with early NNRTI and PI discontinuation in this population, and some factors were ART class specific.

CYP2B6 variants and plasma efavirenz concentrations during antiretroviral therapy in Port-au-Prince, Haiti

BACKGROUND

Polymorphisms in CYP2B6 are known to predict increased steady-state plasma concentrations of efavirenz. We characterized relationships between genetic polymorphisms and plasma efavirenz concentrations among 45 Haitians who initiated antiretroviral therapy in Port-au-Prince.

METHODS

An observational study characterized relationships between clinical factors, pharmacokinetics, and treatment response among antiretroviral-naive patients initiating once-daily treatment with efavirenz plus twice-daily treatment with zidovudine and lamivudine. Plasma drug concentrations were determined at weeks 2 and 4. Drug doses were directly observed by field workers or designated family members. We retrospectively characterized relationships between efavirenz concentrations and 50 single-nucleotide polymorphisms in CYP2B6 and several polymorphisms in CYP2A6, CYP3A4, CYP3A5, and ABCB1.

RESULTS

Plasma specimens for efavirenz analysis were obtained from study participants a mean (+/- standard deviation) of 13.9 +/- 1.6 h after they received the dose. As expected, CYP2B6 516G-->T was associated with increased plasma efavirenz concentrations (Spearman rho = 0.71; P < .001), as were 10 polymorphisms in linkage disequilibrium with 516G-->T. Distinct CYP2B6 polymorphisms were associated with decreased plasma efavirenz concentrations (greatest absolute rho = 0.48; P = .001). Associations were replicated by results from a recent pharmacokinetic study involving 34 healthy, human immunodeficiency virus-negative African Americans.

CONCLUSIONS

Relatively frequent CYP2B6 polymorphisms may predict decreased plasma efavirenz exposure in patients of African descent. If replicated in other cohorts, the implications of these novel associations for treatment response warrant further study.

Treatment responses in antiretroviral treatment-naive premenopausal and postmenopausal HIV-1-infected women: an analysis from AIDS Clinical Trials Group Studies

Menopause may affect antiretroviral treatment (ART) response. Immunologic and virologic responses to ART were compared in 220 premenopausal and 47 postmenopausal women enrolled in 2 studies involving ART-naive persons. Changes in CD4 counts or human immunodeficiency virus type 1 RNA levels were similar at 24, 48, and 96 weeks after treatment initiation. ART-naive women should respond to ART regardless of menopausal status.

HLA-B*5701 screening prior to abacavir prescription: clinical and laboratory aspects

This review focuses on the development of HLA-B*5701 genetic screening as a means of preventing drug hypersensitivity reactions caused by a commonly prescribed antiretroviral drug, abacavir. This strongly predictive genetic association, which in many respects represents a test case for the clinical application of pharmacogenetics, highlights the fine specificity of HLA-restricted immunity, here directed against a drug-specific antigen rather than an allogeneic molecule (as occurs in transplantation) or a pathogenic organism (as in viral infection). However, this example also demonstrates that successful implementation of pharmacogenetic screening requires that a range of criteria be adequately addressed. These include pharmaceutical factors (e.g. lack of alternative treatments with similar or improved cost effectiveness, safety, and efficacy), clinical factors (e.g. accurate diagnosis of the adverse event, in this case provided by clinical diagnostic criteria and adjunctive epicutaneous patch testing), sufficient objective evidence of the test's predictive value and generalizability (in this case provided by the first large-scale randomized trial of a pharmacogenetic test), as well as availability of quality-assured laboratory services that are responsive to the needs of targeted genetic screening. This example is intended to serve as a precedent for other pharmacogenetic screening strategies, particularly those aimed at reducing rates of serious drug hypersensitivity reactions in clinical practice.

Successful translation of pharmacogenetics into the clinic: the abacavir example

Abacavir hypersensitivity syndrome (AHS) is a potentially life-threatening illness occurring in 4-8% of those initiating the drug. Early studies identified a strong association between the MHC class I allele HLA-B*5701 and AHS. These studies suggested that HLA-B*5701 holds promise as a screening test to prevent AHS, but concern arose from HLA-B*5701-negative cases with a clinical diagnosis of AHS, and particularly from early reports of apparently low sensitivities of HLA-B*5701 for AHS in patients of non-White race. However, open screening studies suggested that HLA-B*5701 screening can largely eliminate AHS. Furthermore, skin-patch testing was used in later-generation studies to separate those patients with true immunologically mediated AHS from those with false-positive clinical diagnoses. Currently, high-level evidence suggests that HLA-B*5701 has a negative predictive value of 100% for patch-test-confirmed AHS, which is generalizable across White and Black populations. Current HIV treatment guidelines have been revised to reflect the recommendation that HLA-B*5701 screening be incorporated into routine care for patients who may require abacavir. New laboratory techniques such as PCR and flow cytometric methods, as well as an international quality assurance program, have evolved to ensure the availability of cost-effective screening methods whose consistency and standard can be maintained over time. An elegant body of basic science has evolved, which supports and complements the clinical research in suggesting that AHS is specifically and exquisitely restricted by HLA-B*5701 and mediated by CD8+ lymphocytes. Abrogating factors explaining why 45% of those carrying HLA-B*5701 can tolerate abacavir remain to be defined. The research approach applied to AHS has led to a genetic screening test being successfully implemented globally in primary HIV clinical practice. The abacavir 'example' can be applied to other drugs to facilitate the development and operationalization of genetic tests that may be useful to predict and prevent otherwise unpredictable drug reactions.

Prevalence and persistence of cervical human papillomavirus infection in HIV-positive women initiating highly active antiretroviral therapy

OBJECTIVE

To determine the prevalence of human papillomavirus (HPV) DNA in cervical specimens from treatment-naive women initiating highly active antiretroviral therapy (HAART) and explore the longitudinal association of HPV DNA with CD4 count and HIV viral load (VL).

METHODS

Women enrolled before HAART were evaluated at baseline, weeks 24, 48, and 96 with CD4 count, VL, and cervical swab for HPV DNA.

RESULTS

The 146 subjects had a median CD4 count of 238 cells per microliter and VL of 13,894 copies per milliliter. Ninety-seven subjects (66%) had HPV DNA detected in the baseline specimen including 90 subjects (62%) positive for 1 or more high-risk HPV types. HPV DNA detection declined to 49% at week 96 and that of a high risk HPV type to 39%. The duration of follow-up was associated with decreased detection of HPV DNA of any type (P = 0.045) and of high-risk HPV types (P = 0.003). There was at most a marginal association between HAART response and loss of detection of cervical HPV DNA.

CONCLUSIONS

Women initiating HAART had a high prevalence of cervical HPV DNA that declined over 96 weeks of HAART. The relationship of CD4 count and VL response to the decline of cervical HPV DNA was not strong.

Antiretroviral treatment of HIV infection: Swedish recommendations 2007

On 3 previous occasions, in 2002, 2003 and 2005, the Swedish Medical Products Agency (Läkemedelsverket) and the Swedish Reference Group for Antiviral Therapy (RAV) have jointly published recommendations for the treatment of HIV infection. An expert group, under the guidance of RAV, has now revised the text again. Since the publication of the previous treatment recommendations, 1 new drug for the treatment of HIV has been approved - the protease inhibitor (PI) darunavir (Prezista). Furthermore, 3 new drugs have become available: the integrase inhibitor raltegravir (MK-0518), the CCR5-inhibitor maraviroc (Celsentri), both of which have novel mechanisms of action, and the non-nucleoside reverse transcriptase inhibitor (NNRTI) etravirine (TMC-125). The new guidelines differ from the previous ones in several respects. The most important of these are that abacavir is now preferred to tenofovir and zidovudine, as a first line drug in treatment-naïve patients, and that initiation of antiretroviral treatment is now recommended before the CD4 cell count falls below 250/microl, rather than 200/microl. Furthermore, recommendations on the treatment of HIV infection in children have been added to the document. As in the case of the previous publication, recommendations are evidence-graded in accordance with the Oxford Centre for Evidence Based Medicine, 2001 (see http://www.cebm.net/levels_of_evidence.asp#levels).

Personalizing antiretroviral therapy: is it a reality?

The concept of personalizing antiretroviral therapy is not novel, since the complexity of the HIV patient and their therapy has always demanded consideration of the patient's 'pharmacoecology', taking into account factors such as adherence, drug-drug and food-drug interactions, underlying disease and host states, such as organ dysfunction and pregnancy. Recent advances in science have taken this one step further with the technology now available to use both a candidate and whole-genome approach to explore the genetics of host-virus interactions, as well as the pharmacogenetics of the toxicity and efficacy of antiretroviral therapy. The genetics of host-virus interactions have improved our understanding of the pathogenesis of HIV which will aid in the research and development of an HIV vaccine. Most published HIV pharmacogenetic studies have utilized a candidate gene approach. Although these types of studies have provided insight into the pathogenesis and pharmacogenetics of drug disposition, drug interactions, drug efficacy and toxicity and host-virus interactions, very few will lend themselves to a widespread clinical application. The application of HLA-B*5701 screening to prevent abacavir hypersensitivity acts as an important example of the successful widespread implementation of a pharmacogenetic test into the clinic and defines the key steps necessary for the clinical application of pharmacogenetic tests in general.

Long-term consequences of the delay between virologic failure of highly active antiretroviral therapy and regimen modification

OBJECTIVES

Current treatment guidelines recommend immediate modification of antiretroviral therapy in HIV-infected individuals with incomplete viral suppression. These recommendations have not been tested in observational studies or large randomized trials. We evaluated the consequences of delayed modification following virologic failure.

DESIGN/METHODS

We used prospective data from two clinical cohorts to estimate the effect of time until regimen modification following first regimen failure on all-cause mortality. The impact of regimen type was also assessed. As the effect of delayed switching can be confounded if patients with a poor prognosis modify therapy earlier than those with a good prognosis, we used a statistical methodology - marginal structural models - to control for time-dependent confounding.

RESULTS

A total of 982 patients contributed 3414 person-years of follow-up following first regimen failure. Delay until treatment modification was associated with an elevated hazard of all-cause mortality among patients failing a reverse transcriptase inhibitor-based regimen (hazard ratio per additional 3 months delay = 1.23, 95% confidence interval: 1.08, 1.40), but appeared to have a small protective effect among patients failing a protease inhibitor-based regimen (hazard ratio per additional 3 months delay = 0.93, 95% confidence interval: 0.87, 0.99).

CONCLUSION

Delay in modification after failure of regimens that do not contain a protease inhibitor is associated with increased mortality. Protease inhibitor-based regimens are less dependent on early versus delayed switching strategies. Efforts should be made to minimize delay until treatment modification in resource-poor regions, where the majority of patients are starting reverse transcriptase inhibitor-based regimens and HIV RNA monitoring may not be available.

Regimen simplification to atazanavir-ritonavir alone as maintenance antiretroviral therapy: final 48-week clinical and virologic outcomes

BACKGROUND

Simplified maintenance therapy with ritonavir-boosted atazanavir (ATV/RTV) alone is attractive because of nucleoside reverse-transcriptase inhibitor (NRTI)-sparing benefits, low pill burden, once-daily dosage, and safety.

METHODS

Subjects with virologic suppression after > or = 48 weeks of initial antiretroviral therapy with 2 NRTIs and a protease inhibitor (PI) were enrolled. Subjects switched to ATV/RTV at entry and discontinued NRTIs after 6 weeks. The primary end point was time to virologic failure (confirmed HIV-1 RNA level > or = 200 copies/mL). Drug resistance at virologic failure was evaluated by standard genotyping and single-genome sequencing (SGS). Residual viremia (1.1-49 copies/mL) was measured by single-copy assay.

RESULTS

Thirty-four subjects simplified to ATV/RTV alone, of whom 30 (88%) did not experience virologic failure by 48 weeks after simplification. Residual viremia did not change significantly after NRTI discontinuation among those without virologic failure but did increase 4-12 weeks before confirmed virologic failure. No major PI-resistance mutations were identified at virologic failure by standard genotyping or SGS.

CONCLUSIONS

In this pilot study, simplified maintenance therapy with ATV/RTV alone maintained viral suppression in most subjects through 48 weeks. PI resistance was not detected among subjects experiencing virologic failure. Larger, randomized trials are warranted to further define the efficacy and safety of this strategy.

Italian consensus statement on management of HIV-infected individuals with advanced disease naïve to antiretroviral therapy

BACKGROUND

Individuals with advanced HIV infection naïve to antiretroviral therapy represent a special population of patients frequently encountered in clinical practice. They are at high risk of disease progression and death, and their viroimmunologic response following the initiation of highly active antiretroviral therapy may be more incomplete or slower than that of other patients. Infection management in such patients can also be complicated by underlying conditions, comorbidities, and the need for concomitant medications.

AIM

To provide practical guidelines to those clinicians providing care to HIV-infected patients in terms of diagnostic assessment, monitoring, and treatment.

CONCLUSIONS

The principals of antiretroviral treatment in asymptomatic naïve patients with advanced HIV infection are the same as those applicable to the general population with asymptomatic HIV infection. Naïve patients with advanced HIV infection and a history of AIDS-defining illnesses urgently need antiretroviral treatment, with the choice of antiretroviral regimen and timetable based on such factors as concomitant treatment and prophylaxis, drug interactions, and potential concomitant drug toxicity. Finally, an adequate counseling program - both before and after HIV-testing - that includes aspects other than treatment adherence monitoring is a crucial step in disease management.

Absence of a relation between efavirenz plasma concentrations and toxicity-driven efavirenz discontinuations in the EuroSIDA study

Background

Conflicting data exist regarding the effect of efavirenz (EFV) plasma concentrations on central nervous system (CNS) toxicity. We aimed to determine whether patients with high EFV plasma concentrations have an increased likelihood of toxicity-driven EFV discontinuations.

Methods

EFV plasma concentrations were measured from patients in the EuroSIDA study starting EFV after 1 January 1999. Patients with a plasma concentration available were divided into those that discontinued EFV because of any toxicity or by the choice of the patient or physician within 2 years (TOXPC group) and those that continued EFV for ≥2 years (no toxicity group). Multivariable logistic regression modelling was used to investigate the effects of the EFV plasma concentration and those of other potentially relevant factors on the risk of toxicity-induced EFV discontinuations.

Results

A total of 843 patients were included. Of these patients, 138 patients (16.4%) discontinued EFV because of TOXPC and 705 (83.6%) patients continued EFV for ≥2 years. A total of 20 (14.5%) patients in the TOXPC group had high EFV plasma concentrations (>4.0 mg/l) compared with 99 (14.0%) patients in the no toxicity group ( P=0.890). A positive hepatitis C status ( P=0.026), but not the EFV plasma concentration, was an independent predictor of toxicity-driven EFV discontinuations.

Conclusions

No association was found between EFV plasma concentrations and the risk of EFV discontinuations because of (CNS) toxicity. This result questions the designation of EFV plasma concentrations >4.0 mg/l as being ‘toxic’, at least when defined by treatment discontinuation.

Simplification Strategies to Reduce Antiretroviral drug Exposure: Progress and Prospects

Current US guidelines for initial therapy of HIV type-1 (HIV-1) infection recommend daily, lifelong treatment with a combination of three antiretroviral drugs consisting of two nucleoside analogue reverse transcriptase inhibitors and a non-nucleoside reverse transcriptase inhibitor or a protease inhibitor. Although this approach has been successful in reducing morbidity and mortality from HIV-1 infection, concerns remain about adverse events from chronic drug exposure, the requirement for daily medication adherence, the risk of HIV-1 drug resistance and high treatment costs. The availability of antiretrovirals that are coformulated and dosed once daily have reduced pill burden and have simplified dosing schedules, but have not lowered drug exposure or cost. These limitations have stimulated research into drug-sparing strategies including intermittent therapy and simplified maintenance regimens. Randomized clinical trials have shown greater mortality with intermittent therapy compared with continuous therapy leading to rejection of this strategy. Pilot studies of simplified maintenance therapy with a ritonavir-boosted protease inhibitor alone have shown more promise, although concerns remain. This article reviews progress in the simplification of antiretroviral therapy, recent clinical trial results and prospects for the future.

Antiretroviral therapy during infancy: essential intervention for resource-limited settings

EVALUATION OF: Prendergast A, Mphatswe W, Tudor-Williams G et al. Early virological suppression with three-class antiretroviral therapy in HIV-infected African infants. AIDS 22, 1333-1343 (2008). There is limited information regarding the outcome of infants treated with highly active antiretroviral therapy (HAART) in middle- and low-income countries. The mean/median age of children enrolled on HAART in these countries is generally high; however, it is acknowledged that untreated HIV-infected children under 2 years of age, including infected infants, are an extremely vulnerable group. This article assessed the findings of a recently published paper describing the outcome of 63 infants randomized to commence immediate or deferred HAART in a resource-poor setting and documented favorable short-term outcome in both groups, with correspondingly high adherence rates. The recent change in global treatment guidelines, recommending that all HIV-infected infants should be commenced on HAART soon after diagnosis, irrespective of their clinical status and/or immunological severity, is discussed in relation to the key findings of the article.

Short-term discontinuation of HAART regimens more common in vulnerable patient populations

The durability of HAART regimens is often limited by antiretroviral toxicity and nonadherence, which lead to virologic failure. We sought to determine sociodemographic and psychosocial patient factors predictive of short-term discontinuation of HAART regimens overall and stratified by the reason for discontinuation. A retrospective cohort study of the UAB 1917 Clinic Cohort evaluated short-term HAART regimen discontinuation (within 12 months of regimen initiation) between 1/1995 and 8/2004 classified as (1) gastrointestinal (GI) toxicity, (2) non-GI toxicity, (3) virologic failure or nonadherence (VF/NA), (4) loss to follow-up, and (5) other. Multivariable multinomial logistic regression models accounting for dependent observations were fit to assess the relationship between patient factors and type-specific regimen discontinuation. Among the 738 study participants, 1026 of 1852 HAART regimens (55%) were discontinued within 12 months of initiation. In multivariable analysis, discontinuation for GI toxicity was more common in patients lacking private health insurance and those with a history of intravenous (IV) drug use, whereas non-GI toxicity was more common in younger patients and females. African-American patients and those with a history of IV drug use were more likely to stop a regimen due to VF/NA. Loss to follow-up was more common in younger patients, individuals who were uninsured, and those with a history of IV drug use. Short-term discontinuation of HAART regimens is more common in vulnerable populations that bear a disproportionate burden of the U.S. HIV/AIDS epidemic. More vigilant monitoring of patient populations at higher risk of toxicity and virologic failure may allow for improved HAART regimen durability.

Virologic success in an urban HIV clinic: outcome at 12 months in patients who were HAART naïve

BACKGROUND

Randomized controlled trials with highly active antiretroviral therapy (HAART) have demonstrated over 70% virologic success rates, although patients in an inner city HIV setting likely have lower virologic success.

METHOD

We studied the outcome of all treatment-naive patients beginning HAART in our urban clinic in Philadelphia, Pennsylvania. The primary outcome was virologic success at 12 months for all patients who were initiated on HAART. Secondary outcomes included virologic success at 12 months for only those who remained in care and the determination of which demographics influenced virologic success.

RESULTS

Between 2003 and 2005, 109 patients were initiated on HAART: 39% women, 79% African American, 17% Hispanic, median CD4+ count 120 cells/mm3, and HIV-1 RNA 4.9 log10 copies/mL. Twenty-two were lost to follow-up after HAART initiation. Of the 87 who remained in care, 41 maintained a HIV-1 RNA <400 copies/mL through 12 months on their initial HAART regimen. Emerging drug resistance was documented in 7 of 87 patients. NNRTI-based HAART was significantly associated with greater virologic failure due to emerging resistance compared to a PI-based regimen.

CONCLUSION

Our retrospective study demonstrates the difficulties in administering successful HIV care to an urban population, and efforts to help patients overcome barriers to consistent medical care must be a priority.

Cost-effectiveness of HIV monitoring strategies in resource-limited settings: a southern African analysis

BACKGROUND

Although the number of infected persons receiving highly active antiretroviral therapy (HAART) in low- and middle-income countries has increased dramatically, optimal disease management is not well defined.

METHODS

We developed a model to compare the costs and benefits of 3 types of human immunodeficiency virus monitoring strategies: symptom-based strategies, CD4-based strategies, and CD4 counts plus viral load strategies for starting, switching, and stopping HAART. We used clinical and cost data from southern Africa and performed a cost-effectiveness analysis. All assumptions were tested in sensitivity analyses.

RESULTS

Compared with the symptom-based approaches, monitoring CD4 counts every 6 months and starting treatment at a threshold of 200/muL was associated with a gain in life expectancy of 6.5 months (61.9 months vs 68.4 months) and a discounted lifetime cost savings of US $464 per person (US $4069 vs US $3605, discounted 2007 dollars). The CD4-based strategies in which treatment was started at the higher threshold of 350/microL provided an additional gain in life expectancy of 5.3 months at a cost-effectiveness of US $107 per life-year gained compared with a threshold of 200/microL. Monitoring viral load with CD4 was more expensive than monitoring CD4 counts alone, added 2.0 months of life, and had an incremental cost-effectiveness ratio of US $5414 per life-year gained relative to monitoring of CD4 counts. In sensitivity analyses, the cost savings from CD4 count monitoring compared with the symptom-based approaches was sensitive to cost of inpatient care, and the cost-effectiveness of viral load monitoring was influenced by the per test costs and rates of virologic failure.

CONCLUSIONS

Use of CD4 monitoring and early initiation of HAART in southern Africa provides large health benefits relative to symptom-based approaches for HAART management. In southern African countries with relatively high costs of hospitalization, CD4 monitoring would likely reduce total health care expenditures. The cost-effectiveness of viral load monitoring depends on test prices and rates of virologic failure.

AIDS clinical trials group longitudinal linked randomized trials (ALLRT): rationale, design, and baseline characteristics

PURPOSE

ALLRT is a longitudinal cohort study of HIV-infected subjects prospectively randomized into selected clinical trials for antiretroviral (ARV) treatment-naïve and ARV treatment-experienced individuals conducted by the AIDS Clinical Trials Group (ACTG). We describe the rationale, design, and baseline characteristics of the ALLRT cohort and its potential to address important research questions related to ARV therapy.

METHOD

Standardized visits occur every 16 weeks to evaluate long-term clinical, virologic, and immunologic outcomes associated with ARV treatment.

RESULTS

A total of 4,371 subjects enrolled in ALLRT from January 2000 through June 2007. Of these, 3,146 (72%) were ARV naïve at parent study entry (18% female, 44% white, 32% black, 21% Hispanic; median age 37 years, CD4 count 218 cells/microL, follow-up 3.6 years; 343 [11%] followed > or = 8 years) and 1,225 (28%) were treatment experienced (13% female, 59% white, 20% black, 17% Hispanic; median age 42 years, CD4 count 325 cells/microL, follow-up 5.7 years).

CONCLUSIONS

ALLRT provides the opportunity to understand long-term ramifications of therapeutic ARV choices and determine whether these vary by treatment regimen, timing of treatment initiation, or treatment changes over long-term follow-up. Investigations based on uniform data and specimen collection in the context of randomized ARV treatments will be critical to developing more successful long-term therapeutic strategies for HIV treatment.

Clinical impact of patient population differences and genomic variation in efavirenz therapy

Guidelines for use of antiretroviral agents presently recommend first-line treatments with nonnucleoside reverse transcriptase inhibitor-based regimens. Efavirenz is the standard-of-care comparator for nonnucleoside reverse transcriptase inhibitor-based antiretroviral therapy. As with many antiretroviral medications, efavirenz is subject to interindividual variation in metabolism, effectiveness, and tolerability. Demographic factors such as age, sex, and ethnicity have been demonstrated to influence this variability, but other underlying factors such as genetics, disease state, and concomitant drug use can also play a role. The clinical impactions of these factors are only beginning to be understood. Although significant advances have led to a greater understanding of interactions between genetic and host factors that influence the efficacy and toxicity of efavirenz, providers should not withhold treatment of HIV infection with an efavirenz-based regimen on the basis of racial or ethic categorizations.

Durability and outcome of initial antiretroviral treatments received during 2000--2005 by patients in the Swiss HIV Cohort Study

BACKGROUND

Little is known about time trends, predictors, and consequences of changes made to antiretroviral therapy (ART) regimens early after patients initially start treatment.

METHODS

We compared the incidence of, reasons for, and predictors of treatment change within 1 year after starting combination ART (cART), as well as virological and immunological outcomes at 1 year, among 1866 patients from the Swiss HIV Cohort Study who initiated cART during 2000--2001, 2002--2003, or 2004--2005.

RESULTS

The durability of initial regimens did not improve over time (P = .15): 48.8% of 625 patients during 2000--2001, 43.8% of 607 during 2002--2003, and 44.3% of 634 during 2004--2005 changed cART within 1 year; reasons for change included intolerance (51.1% of all patients), patient wish (15.4%), physician decision (14.8%), and virological failure (7.1%). An increased probability of treatment change was associated with larger CD4+ cell counts, larger human immunodeficiency virus type 1 (HIV-1) RNA loads, and receipt of regimens that contained stavudine or indinavir/ritonavir, but a decreased probability was associated with receipt of regimens that contained tenofovir. Treatment discontinuation was associated with larger CD4+ cell counts, current use of injection drugs, and receipt of regimens that contained nevirapine. One-year outcomes improved between 2000--2001 and 2004--2005: 84.5% and 92.7% of patients, respectively, reached HIV-1 RNA loads of <50 copies/mL and achieved median increases in CD4+ cell counts of 157.5 and 197.5 cells/microL, respectively (P < .001 for all comparisons).

CONCLUSIONS

Virological and immunological outcomes of initial treatments improved between 2000--2001 and 2004--2005, irrespective of uniformly high rates of early changes in treatment across the 3 study intervals.

Initial therapy with nucleoside reverse transcriptase inhibitor-containing regimens is more effective than with regimens that spare them with no difference in short-term fat distribution: Hippocampe-ANRS 121 Trial

OBJECTIVES

The aim of this study was to evaluate the impact on body fat of nucleoside reverse transcriptase inhibitor (NRTI)-sparing regimens compared with NRTI-containing therapy in HIV-1-infected antiretroviral (ARV)-naive patients.

METHODS

A randomized, multicentre, open-label trial in ARV-naive patients. Subjects were randomized (2:1:1) to receive: (i) an NRTI-sparing regimen consisting of a non-nucleoside reverse transcriptase inhibitor (NNRTI) plus a boosted protease inhibitor (PI/r); or (ii) an NRTI-containing regimen of (a) a PI/r plus two NRTIs or (b) an NNRTI plus two NRTIs. The primary endpoint was the change in subcutaneous limb fat measured by dual-energy X-ray absorptiometry at week (W) 96. Secondary endpoints included the proportion of patients with treatment failure, plasma HIV-RNA (pVL) <50 copies/mL and safety.

RESULTS

One hundred and seventeen patients were enrolled between November 2003 and May 2004: 26% female; 42% from sub-Saharan Africa; median plasma HIV-RNA (pVL) 5.1 log(10) copies/mL; median CD4 count 207 cells/mm(3). A planned interim analysis demonstrated significantly lower treatment and virological responses with the NRTI-sparing strategy, resulting in premature study termination on 19 July 2005. The proportion of patients who remained on their assigned treatment strategy and had pVL <50 copies/mL on the NRTI-sparing regimen was 60.0%, compared with 82.5% on the NRTI-containing regimen at W24 (P = 0.009) and 66.7% and 82.5%, respectively, at W48 (P = 0.059). Treatment failure was associated with the NRTI-sparing strategy in patients with suboptimal adherence and with being from sub-Saharan Africa. No differences in fat distribution were noted.

CONCLUSIONS

An initial NRTI-sparing regimen is less successful and virologically less potent than standard NRTI-containing regimen and should not therefore be used as the first line of treatment.

Clinical outcome of HIV-infected antiretroviral-naive patients with discordant immunologic and virologic responses to highly active antiretroviral therapy

BACKGROUND

The prognostic significance of a response to highly active antiretroviral therapy (HAART) that is immunologically and virologically discordant is not well understood.

METHODS

Four hundred four antiretroviral-naive patients initiating HAART at an urban HIV outpatient clinic in 1995 to 2004 were analyzed. The association of treatment responses at 3 to 9 months after HAART initiation with time to development of an opportunistic infection (OI) or death was determined using Cox proportional hazards modeling. Logistic regression modeling was used to examine the association between discordant responses and patient characteristics.

RESULTS

Of 404 patients, 70.5% experienced favorable concordant responses (CD4 cell count [CD4]+/viral load [VL]+: increase in CD4 count of >or=50 cells/microL and achievement of undetectable plasma HIV RNA level), 15.8% an immunologic response only (CD4+/VL(-)), 8.7% a virologic response only (CD4(-)/VL+), and 5.0% a concordant unfavorable response (CD4(-)/VL(-)). Both types of discordant responses (CD4+/VL(-) and CD4(-)/VL+), nonresponse (CD4(-)/VL(-)), and baseline CD4 cell count were significantly associated with earlier development of an OI or death (relative hazard [RH] = 2.81, 95% confidence interval [CI]: 1.31 to 3.97; RH = 4.83, 95% CI: 2.10 to 11.12; and RH = 0.93, 95% CI: 0.88 to 0.99, respectively). CD4+/VL(-) and CD4(-)/VL(-) were associated with nonwhite race in multivariate logistic regression models (adjusted OR = 2.83, 95% CI: 1.46 to 5.47 and adjusted OR = 6.50, 95% CI: 1.65 to 25.69, respectively).

CONCLUSION

Discordant immunologic and virologic responses at 3 to 9 months after HAART initiation play important roles in predicting long-term clinical outcomes in treatment-naive patients.

Preexisting resistance to nonnucleoside reverse-transcriptase inhibitors predicts virologic failure of an efavirenz-based regimen in treatment-naive HIV-1-infected subjects

A case-cohort study was used to determine the effect of baseline nonnucleoside reverse-transcriptase inhibitor (NNRTI) resistance, as assessed by viral genotyping, on the response to efavirenz-containing regimens in AIDS Clinical Trials Group A5095. The sample included a random cohort of efavirenz-treated subjects plus unselected subjects who experienced virologic failure. Of 220 subjects in the random cohort, 57 (26%) had virologic failure. The prevalence of baseline NNRTI resistance was 5%. The risk of virologic failure for subjects with baseline NNRTI resistance was higher than that for subjects without such resistance (hazard ratio 2.27 [95% confidence interval], 1.15-4.49; P = .018). These results support resistance testing before starting antiretroviral therapy.

Efavirenz-based regimens in treatment-naive patients with a range of pretreatment HIV-1 RNA levels and CD4 cell counts

The potency of 2 nucleoside reverse transcriptase inhibitors (NRTIs) and efavirenz in patients with higher viral loads (VLs) or low CD4 cell counts remains uncertain. Virologic failure and changes in CD4 count in relation to pretreatment VL and CD4 count were evaluated in treatment-naive patients randomized to treatment groups that received 2 or 3 NRTIs with efavirenz. Over 3 years, the risk of virologic failure was not significantly different among subgroups categorized according to pretreatment VL or CD4 count. No significant differences among subgroups were observed for CD4 count changes, except in patients with high pretreatment VL. There were no significant differences among subgroups with respect to treatment responses. These results demonstrate the potency of efavirenz-containing regimens across a spectrum of pretreatment VLs and CD4 counts.

The influence of psychosocial characteristics and race/ethnicity on the use, duration, and success of antiretroviral therapy

BACKGROUND

Expanded access to antiretroviral therapy (ART) has produced dramatic reductions in HIV-associated morbidity and mortality. Disparities in access to and benefit from ART have been observed by race, gender, and mental health status, however.

METHODS

From 2001 to 2002, 611 HIV-positive patients were consecutively recruited from 5 southeastern US states and followed for 3 years. We evaluated demographic and psychosocial predictors of probability of receiving ART among all those eligible for ART (on ART, CD4 <350 cells/mm3 or viral load [VL] >55,000 copies/mL in the year preceding enrollment), time to first ART discontinuation among those on ART, and time to VL >400 copies/mL among those on ART with VL <400 copies/mL at enrollment.

RESULTS

Of 611 participants, 474 consented to medical record abstraction and had known ART status at enrollment; 81% (385 of 474) of all participants and 89% (385 of 435) of ART-eligible participants were receiving ART at enrollment. In multivariable analyses, ART receipt was associated with greater age (adjusted odds ratio = 1.92 per 10 years, 95% confidence interval: 1.23 to 3.01), fewer recent stressful life events (odds ratio = 0.68, 95% confidence interval: 0.51 to 0.92), less alcohol use (odds ratio = 0.64, 95% confidence interval: 0.46 to 0.90), and greater perceived self-efficacy (OR = 2.82, 95% confidence interval: 1.41 to 5.62). No psychosocial characteristics were associated with ART discontinuation or virologic failure. No racial/ethnic or gender disparities were observed in ART receipt; however, minority racial/ethnic groups were faster to discontinue ART (adjusted hazard ratio = 2.44, 95% confidence interval: 1.33 to 4.49) and experience virologic failure (adjusted hazard ratio = 2.01, 95% confidence interval: 1.09 to 3.71).

CONCLUSIONS

Patients with unfavorable psychosocial profiles were less likely to be on ART, perhaps attributable to providers' or patients' expectations of readiness. Psychosocial characteristics were not associated with ART discontinuation or virologic failure, however, possibly reflecting the selection process involved in who initiates ART. Racial disparities in ART discontinuation and virologic failure merit further attention.

Pharmacogenetics and the potential for the individualization of antiretroviral therapy

PURPOSE OF REVIEW

Genetic associations highlighting differences in the response to HIV infection and treatment have significantly furthered our understanding of the pathogenesis, pharmacokinetics and pharmacodynamics of antiretroviral drug action and toxicities and HIV disease itself. This review focuses on the current knowledge of associations between polymorphisms and treatment outcomes in HIV with particular emphasis on clinically relevant relationships likely to lead to the individualization of antiretroviral therapy.

RECENT FINDINGS

Our understanding of the immunogenetic basis of drug toxicity has been furthered by human leucocyte antigen associations with hypersensitivities for the antiretroviral drugs abacavir and nevirapine. For abacavir in particular, the use of HLA-B*5701 as a screening test appears to be generalizable across racially diverse populations and has been supported by both observational, and blinded randomized controlled trials.

SUMMARY

Differences in HIV acquisition and progression as well as antiretroviral efficacy and toxicity will continue to provide the basis for research to define the genetic basis of such diversity. Despite the plethora of research in this area, numerous barriers exist to the successful operationalization of genetic testing to the clinic. HLA-B*5701 screening to prevent abacavir hypersensitivity is currently the most relevant to clinical practice and highlights that the promise of cost-effective testing can be facilitated by robust laboratory methodology and quality assurance programs that can be applied to diverse treatment settings.

Antiretroviral therapy : optimal sequencing of therapy to avoid resistance

In the second decade of highly active antiretroviral therapy, drug regimens offer more potent, less toxic and more durable choices. However, strategies addressing convenient sequential use of active antiretroviral combinations are rarely presented in the literature. Studies have seldom directly addressed this issue, despite it being a matter of daily use in clinical practice. This is, in part, because of the complexity of HIV-1 resistance information as well as the complexity of designing these types of studies. Nevertheless, several principles can effectively assist the planning of antiretroviral drug sequencing. The introduction of tenofovir disoproxil fumarate, abacavir and emtricitabine into current nucleoside backbone options, with each of them selecting for an individual pattern of resistance mutations, now permits sequencing in the context of previously popular thymidine analogues (zidovudine and stavudine). Similarly, newer ritonavir-boosted protease inhibitors could potentially be sequenced in a manner that uses the least cross-resistance prone protease inhibitor at the start of therapy, while leaving the most cross-resistance prone drugs for later, as long as there is rationale to employ such a compound because of its utility against commonly observed drug-resistant forms of HIV-1.

HLA-B*5701 screening for hypersensitivity to abacavir

BACKGROUND

Hypersensitivity reaction to abacavir is strongly associated with the presence of the HLA-B*5701 allele. This study was designed to establish the effectiveness of prospective HLA-B*5701 screening to prevent the hypersensitivity reaction to abacavir.

METHODS

This double-blind, prospective, randomized study involved 1956 patients from 19 countries, who were infected with human immunodeficiency virus type 1 and who had not previously received abacavir. We randomly assigned patients to undergo prospective HLA-B*5701 screening, with exclusion of HLA-B*5701-positive patients from abacavir treatment (prospective-screening group), or to undergo a standard-of-care approach of abacavir use without prospective HLA-B*5701 screening (control group). All patients who started abacavir were observed for 6 weeks. To immunologically confirm, and enhance the specificity of, the clinical diagnosis of hypersensitivity reaction to abacavir, we performed epicutaneous patch testing with the use of abacavir.

RESULTS

The prevalence of HLA-B*5701 was 5.6% (109 of 1956 patients). Of the patients receiving abacavir, 72% were men, 84% were white, and 18% had not previously received antiretroviral therapy. Screening eliminated immunologically confirmed hypersensitivity reaction (0% in the prospective-screening group vs. 2.7% in the control group, P<0.001), with a negative predictive value of 100% and a positive predictive value of 47.9%. Hypersensitivity reaction was clinically diagnosed in 93 patients, with a significantly lower incidence in the prospective-screening group (3.4%) than in the control group (7.8%) (P<0.001).

CONCLUSIONS

HLA-B*5701 screening reduced the risk of hypersensitivity reaction to abacavir. In predominantly white populations, similar to the one in this study, 94% of patients do not carry the HLA-B*5701 allele and are at low risk for hypersensitivity reaction to abacavir. Our results show that a pharmacogenetic test can be used to prevent a specific toxic effect of a drug. (ClinicalTrials.gov number, NCT00340080.)

Optimizing measurement of self-reported adherence with the ACTG Adherence Questionnaire: a cross-protocol analysis

BACKGROUND/OBJECTIVE

The AIDS Clinical Trials Group (ACTG) Adherence Questionnaire is used extensively, but investigators frequently only use the first item of the questionnaire (4-day recall).

DESIGN/METHODS

A secondary analysis was conducted to (1) estimate the validity and reliability of each of the 5 scale items and (2) compare the approach commonly used to summarize adherence data collected with the instrument (average 4-day recall) with alternate approaches derived using principal component (PC) analysis and the full questionnaire. We hypothesized that an estimate of adherence taking all items of the questionnaire into account would provide a stronger measure of adherence.

RESULTS

Logistic regression analyses showed that the first PC identified (PC1) was significantly correlated with plasma HIV RNA outcome (P < 0.0001 for ACTG 370 data and P = 0.006 for ACTG 398 data) and correlated with plasma HIV RNA better than average 4-day recall. An adherence index formulated using weights of PC1 showed substantially greater variability in the range of adherence scores in comparison to average 4-day adherence recall alone. PC1 compared favorably with 2 indices derived from medication event monitoring system data as well.

CONCLUSIONS

Findings indicate that a superior assessment of antiretroviral adherence may be obtained with the ACTG Adherence Questionnaire by using the method employed in this analysis.

Low-level HIV-1 replication and the dynamics of the resting CD4+ T cell reservoir for HIV-1 in the setting of HAART

Background

In the setting of highly active antiretroviral therapy (HAART), plasma levels of human immunodeficiency type-1 (HIV-1) rapidly decay to below the limit of detection of standard clinical assays. However, reactivation of remaining latently infected memory CD4⁺ T cells is a source of continued virus production, forcing patients to remain on HAART despite clinically undetectable viral loads. Unfortunately, the latent reservoir decays slowly, with a half-life of up to 44 months, making it the major known obstacle to the eradication of HIV-1 infection. However, the mechanism underlying the long half-life of the latent reservoir is unknown. The most likely potential mechanisms are low-level viral replication and the intrinsic stability of latently infected cells.

Methods

Here we use a mathematical model of T cell dynamics in the setting of HIV-1 infection to probe the decay characteristics of the latent reservoir upon initiation of HAART. We compare the behavior of this model to patient derived data in order to gain insight into the role of low-level viral replication in the setting of HAART.

Results

By comparing the behavior of our model to patient derived data, we find that the viral dynamics observed in patients on HAART could be consistent with low-level viral replication but that this replication would not significantly affect the decay rate of the latent reservoir. Rather than low-level replication, the intrinsic stability of latently infected cells and the rate at which they are reactivated primarily determine the observed reservoir decay rate according to the predictions of our model.

Conclusion

The intrinsic stability of the latent reservoir has important implications for efforts to eradicate HIV-1 infection and suggests that intensified HAART would not accelerate the decay of the latent reservoir.

Antibodies for HIV treatment and prevention: window of opportunity?

Monoclonal antibodies are routinely used as therapeutics in a number of disease settings and have thus also been explored as potential treatment for human immunodeficiency virus (HIV)-1 infection. Antibodies targeting viral antigens, and those directed to the cellular receptors, have been considered for use in prevention and therapy. For virus-targeted antibodies, attention has focused primarily on their neutralizing activity, but such antibodies also have the potential to exert antiviral effects via effector functions, such as antibody-dependent cellular cytotoxicity (ADCC), opsonization, or complement activation. Anti-cell antibodies act through occlusion or down-modulation of the viral receptors with notable impact in vivo, as recent trials have shown. This review summarizes the diverse specificities and modes of action of therapeutic antibodies against HIV-1 infection. Successes, challenges, and future opportunities of harnessing antibodies for therapy of HIV-1 infection are discussed.