Predictors of long-term response to protease inhibitor therapy in a cohort of HIV-infected patients

Time to initial highly active antiretroviral therapy discontinuation and its predictors among HIV patients in Felege Hiwot comprehensive specialized hospital: a retrospective cohort study

Background

Anti-retroviral therapy regimen discontinuations become a big challenge and cause diminishing the clinical and immunological benefit of treatment in Ethiopia. It reduces both the duration and the chance of viral control due to cross-resistance between different alternative drugs and overlapping toxicity between and within a class of antiretroviral drugs in Ethiopia. However, information’s on the time of initial regimen discontinuation and its predictors are not well studied.

Objective

This study aimed to assess the time to initial highly active antiretroviral therapy discontinuation and its predictors among HIV patients in Felege Hiwot comprehensive specialized hospital, North West Ethiopia.

Method

Institution-based retrospective cohort study was conducted among 418 HIV patients who started HAART from January 1, 2014, to December 31, 2019. Data were collected from the patient chart using a data extraction tool. The Kaplan–Meier curve was employed to compare survival rates. Multivariable Cox proportional hazard regression was applied to identify independent predictors of time to initial regimen discontinuation.

Result

A total of 418 patients on anti-retroviral therapy were followed. Incidence of initial HAART discontinuation was 16.7/100 person year. The median survival time was 3.5 years. Predictors showed association for time to initial HAART discontinuation were taking > 1 ART pills/day (AHR = 4.1, 95% CI 3.0–6.5), baseline CD4 count < 100 cells/mm³ (AHR = 2.6, 95% CI 1.5–4.7), 100–199 cells/mm³ (AHR = 2.2, 95% CI 1.2–4.0), baseline WHO clinical stage IV (AHR = 2.68, 95% CI 1.6–4.3) and stage III (AHR = 2.6, 95% CI 1.4–4.3) and TB infection (AHR = 2.3, 95% CI 1.6–3.5).

Conclusion

Most of the discontinuation occurred after 1 year of initiation of HAART. Baseline WHO clinical stage, TB infection, baseline CD4 count, and taking > 1 ART pill/day were found predictors of initial HAART regimen discontinuation. Work on early detection of HIV before the disease is advanced and initiation of one ART regimen daily is vital for survival on the initial regimen.

Bacterial load slopes represent biomarkers of tuberculosis therapy success, failure, and relapse

There is an urgent need to discover biomarkers that are predictive of long-term TB treatment outcomes, since treatment is expense and prolonged to document relapse. We used mathematical modeling and machine learning to characterize a predictive biomarker for TB treatment outcomes. We computed bacterial kill rates, γ_f for fast- and γ_s for slow/non-replicating bacteria, using patient sputum data to determine treatment duration by computing time-to-extinction of all bacterial subpopulations. We then derived a γ_s-slope-based rule using first 8 weeks sputum data, that demonstrated a sensitivity of 92% and a specificity of 89% at predicting relapse-free cure for 2, 3, 4, and 6 months TB regimens. In comparison, current methods (two-month sputum culture conversion and the Extended-EBA) methods performed poorly, with sensitivities less than 34%. These biomarkers will accelerate evaluation of novel TB regimens, aid better clinical trial designs and will allow personalization of therapy duration in routine treatment programs.

Atazanavir Plus Cobicistat: Week 48 and Week 144 Subgroup Analyses of a Phase 3, Randomized, Double-Blind, Active-Controlled Trial

OBJECTIVES

Cobicistat (COBI) enhances atazanavir (ATV) pharmacokinetic parameters similarly to ritonavir (RTV) in both healthy volunteers and HIV-infected adults. Primary efficacy and safety outcomes of this Phase 3, international, randomized, double-blind, double-dummy, active- controlled trial in HIV-1-infected treatment-naïve adults (GS-US-216-0114/NCT01108510) demonstrated that ATV+COBI was non-inferior to ATV+RTV, each in combination with emtricitabine/ tenofovir disoproxil fumarate (FTC/TDF), at Weeks 48 and 144, with high rates of virologic success for both regimens (85.2% and 87.4%, respectively, at Week 48; and 72.1% and 74.1% at Week 144), and with comparable safety and tolerability. Here, we describe virologic response and treatment discontinuation by a wider range of subgroups than previously presented.

METHODS

Subgroup analyses by baseline CD4 count (≤200, 201-350, &gt;350 cells/mm3), baseline HIV-1 RNA level (≤100,000, &gt;100,000 copies/mL), race, sex, and age (&lt;40, ≥40 years) evaluated ATV+COBI versus ATV+RTV univariate odds ratios (ORs) for virologic success (viral load &lt;50 copies/mL, intention-to-treat US Food and Drug Administration Snapshot algorithm) and discontinuation due to adverse events (AEs) at Weeks 48 and 144. Of 692 patients randomized, 344 received ATV+COBI and 348 ATV+RTV.

RESULTS

ATV+COBI versus ATV+RTV ORs for virologic success did not significantly differ by regimen overall at Weeks 48 and 144 (OR 0.90; 95% confidence interval [CI]: 0.64, 1.26) or within subgroups, except in females, for whom ATV+COBI was favored at Week 144 (OR 2.36; 95% CI: 1.02, 5.47). However, there were more discontinuations due to withdrawal of consent and pregnancies in females receiving ATV+RTV versus ATV+COBI. ORs for discontinuation due to AEs did not significantly differ by regimen overall at Weeks 48 and 144 (OR 0.98; 95% CI: 0.61, 1.58) or within subgroups.

CONCLUSION

These findings indicate that both ATV+COBI and ATV+RTV, each with FTC/TDF, are effective and well-tolerated treatment options across a wide demographic range of HIV-infected patients.

Early virological response to HIV treatment: can we predict who is likely to experience subsequent treatment failure? Results from an observational cohort study, London, UK

INTRODUCTION

For people living with HIV, the first antiretroviral treatment (ART) regimen offers the best chance for a good virological response. Early identification of those unlikely to respond to first-line ART could enable timely intervention and increase chances of a good initial treatment response. In this study we assess the extent to which the HIV RNA viral load (VL) at 1 and 3 months is predictive of first-line treatment outcome at 6 months. Methods All previously ART-naive individuals starting ART at two London centres since 2000 with baseline (-180 to 3 days) VL >500 c/mL had a VL measurement between 6 and 12 months after starting ART, and at least one at month 1 (4-60 days) or month 3 (61-120 days) were included. Lack of treatment response was defined as (i) VL >200 copies/mL at 6 months or (ii) VL >200 copies/mL at 6 months or simultaneous switch in drugs from at least two different drug classes before 6 months. The association with VL measurements at 1 and 3 months post-ART; change from pre-ART in these values; and CD4 count measurements at 1 and 3 months were assessed using logistic regression models. The relative fit of the models was compared using the Akaike information criterion (AIC).

RESULTS

A total of 198 out of 3258 individuals (6%) experienced lack of treatment response at 6 months (definition i), increasing to 511 (16%) for definition (ii). Those with a 1-month (day 4-60 window) VL of <1000, 1000-9999, 10,000-99,999 and >100,000 copies/ml had a 4%, 8%, 23% and 24% chance, respectively, of subsequently experiencing treatment non-response at 6 months (definition (i)). When considering the 3-month (day 61-120 window) VL, the chances of subsequently experiencing treatment non-response were, respectively, 3%, 25%, 67% and 75%. Results were similar for definition (ii).

CONCLUSIONS

Whilst 3-month VL provides good discrimination between low and high risk of treatment failure, 1-month VL does not. Presence of a VL >10,000 copies/ml after 3 months of ART is a cutoff above which individuals are at a sufficiently higher risk of non-response that they may be considered for intervention.

Psychosocial Correlates of Medication Adherence among HIV-Positive, Cognitively Impaired Individuals

Although cognitive impairment has been shown to adversely affect antiviral medication adherence, a subset of cognitively impaired adults nonetheless are able to adequately adhere to their medication regimen. However, little is known about factors that serve as buffers against suboptimal adherence among the cognitively impaired. This study consisted of 160 HIV-positive, cognitively impaired adults (Global Deficit Score ≥ 0.50) whose medication adherence was monitored over 6-months using an electronic monitoring device (MEMS caps). Logistic regressions were run to determine psychosocial variables associated with medication adherence. Higher self-efficacy and treatment related support, a stable medication regimen, stable stress levels, and absence of current stimulant use were predictive of optimal adherence. A distinct array of psychosocial factors was found that buffer against the adverse effects of cognitive impairment on medication adherence. Assessment and interventions targeting these factors may improve adherence rates among cognitively impaired adults.

Duration of first-line antiretroviral therapy in HIV-infected treatment-naive patients in routine practice

BACKGROUND

First-line antiretroviral therapy (1st ART) is an important step in a patient's management and often considered a long-term therapy at treatment initiation.

METHODS

To describe the duration of 1st ART and the factors associated with treatment modification in a recent real-life setting, antiretroviral-naive patients who began their 1st ART in six French hospitals in 2009-2012 were included in a cohort. Clinical, immunological, virological and therapeutic data, as well as the reasons for therapeutic changes, if any, were retrospectively collected.

RESULTS

A total of 206 patients started 1st ART, mainly a protease inhibitor-based triple therapy (73%), with a tenofovir-including backbone (87%). Of these, 89 (43%) had their 1st ART modified after a median of 16.5 months (IQR 8.0-32.8). Having a CD4⁺ T-cell count <200 cells/mm³, being pregnant, or 1st ART including zidovudine + lamivudine or lopinavir/r were significantly associated with a higher risk for treatment modification in multivariate analysis. In 47 patients (53%), 1st ART was modified for safety reasons, with no significant association with a given antiretroviral drug or class. No significant difference in virological, immunological and clinical outcomes was observed between the patients who had their 1st ART modified and those who did not.

CONCLUSIONS

The proportion of modifications of the 1st ART during the first 2 years remains high. These modifications are frequently because of safety issues and the willingness to simplify treatment, and less often driven by virological failure, thus emphasizing that 1st ART is not - or is no longer - a lifelong treatment.

Increases in duration of first highly active antiretroviral therapy over time (1996-2009) and associated factors in the Multicenter AIDS Cohort Study

BACKGROUND

Antiretroviral therapy (ART) regimens changes occur frequently among HIV-infected persons. Duration and type of initial highly active antiretroviral therapy (HAART) and factors associated with regimen switching were evaluated in the Multicenter AIDS Cohort Study.

METHODS

Participants were classified according to the calendar period of HAART initiation: T1 (1996-2001), T2 (2002-2005), and T3 (2006-2009). Kaplan-Meier curves depicted time from HAART initiation to first regimen changes within 5.5 years. Cox proportional hazards regression models were used to examine factors associated with time to switching.

RESULTS

Of 1009 participants, 796 changed regimen within 5.5 years after HAART initiation. The percentage of participants who switched declined from 85% during T1 to 49% in T3. The likelihood of switching in T3 decreased by 50% (P < 0.01) compared with T1 after adjustment for pre-HAART ART use, age, race, and CD4 count. Incomplete HIV suppression decreased over time (P < 0.01) but predicted switching across all time periods. Lower HAART adherence (≤95% of prescribed doses) was predictive of switching only in T1. In T2, central nervous system symptoms predicted switching [relative hazard (RH) = 1.7; P = 0.012]. Older age at HAART initiation was associated with increased switching in T1 (RH = 1.03 per year increase) and decreased switching in T2 (RH = 0.97 per year increase).

CONCLUSIONS

During the first 15 years of the HAART era, initial HAART regimen duration lengthened and regimen discontinuation rates diminished. Both HIV RNA nonsuppression and poor adherence predicted switching before 2001 while side effects that were possibly ART related were more prominent during T2.

Adherence to and effectiveness of highly active antiretroviral treatment for HIV infection: assessing the bidirectional relationship

BACKGROUND

It is well established that high adherence to HIV-infected patients on highly active antiretroviral treatment (HAART) is a major determinant of virological and immunologic success. Furthermore, psychosocial research has identified a wide range of adherence factors including patients' subjective beliefs about the effectiveness of HAART. Current statistical approaches, mainly based on the separate identification either of factors associated with treatment effectiveness or of those associated with adherence, fail to properly explore the true relationship between adherence and treatment effectiveness. Adherence behavior may be influenced not only by perceived benefits-which are usually the focus of related studies-but also by objective treatment benefits reflected in biological outcomes.

METHODS

Our objective was to assess the bidirectional relationship between adherence and response to treatment among patients enrolled in the ANRS CO8 APROCO-COPILOTE study. We compared a conventional statistical approach based on the separate estimations of an adherence and an effectiveness equation to an econometric approach using a 2-equation simultaneous system based on the same 2 equations.

RESULTS

Our results highlight a reciprocal relationship between adherence and treatment effectiveness. After controlling for endogeneity, adherence was positively associated with treatment effectiveness. Furthermore, CD4 count gain after baseline was found to have a positive significant effect on adherence at each observation period. This immunologic parameter was not significant when the adherence equation was estimated separately. In the 2-equation model, the covariances between disturbances of both equations were found to be significant, thus confirming the statistical appropriacy of studying adherence and treatment effectiveness jointly.

CONCLUSIONS

Our results, which suggest that positive biological results arising as a result of high adherence levels, in turn reinforce continued adherence and strengthen the argument that patients who do not experience rapid improvement in their immunologic and clinical statuses after HAART initiation should be prioritized when developing adherence support interventions. Furthermore, they invalidate the hypothesis that HAART leads to "false reassurance" among HIV-infected patients.

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.

Lopinavir: the old champion

Lopinavir/ritonavir approval for use in antiretroviral treatment 10 years ago was very important for the recognition of boosted protease inhibitor (PI)-based therapy as an attractive option for first-line therapy. Being coformulated with ritonavir and having less toxicity than former PIs it allowed for effective and durable virologic suppression with less impact on quality of life. It soon became the standard of care for salvage therapy in its class. Since then, however, its central role has been challenged by new PIs with a more favorable impact on lipid profile, better gastrointestinal tolerability or that are more active in the setting of multidrug resistance. This article summarizes the main clinical studies with lopinavir and discusses its particular characteristics as well as its possible current role in antiretroviral therapy.

Raltegravir as functional monotherapy leads to virological failure and drug resistance in highly treatment-experienced HIV-infected patients

The objective of this study was to evaluate the development of resistance to raltegravir (RAL) in patients with viraemia between 40 and 400 copies/ml. All HIV-1-infected patients with multidrug-resistant virus, plasma HIV-1 RNA >1000 copies/ml and starting RAL were enrolled in this observational study and followed up until week 48. Sixty-seven patients with median plasma HIV-1 RNA at 4.3 log(10) copies/ml and CD4 at 177 cells/mm(3) were included. At week 24, 43 achieved full viral suppression (FVS; plasma HIV-1 RNA <40 copies/ml), 18 had incomplete viral suppression (IVS; plasma HIV-1 RNA 40-<or=400 copies/ml) and 6 experienced virological failure (VF; plasma HIV-1 RNA >400 copies/ml). At week 48, all the FVS were sustained, 16 of the IVS patients retained a plasma HIV-1 RNA <400 copies/ml and only 2 of the IVS at week 24 experienced VF. No RAL resistance was detected in the persistent low viraemia. In contrast, integrase mutation was detected in 6 of the patients with VF. A genotypic sensitivity score equal to 0 was associated with plasma HIV-1 RNA >40 copies/ml at week 24 (OR 20.9, 95% CI 2.0-215.1) and with RAL resistance (OR 14.2, 95% CI 2.1-94.7). This study confirmed the high efficacy of a RAL-containing regimen under routine clinical conditions in infections caused by multidrug-resistant virus. If persistent low viraemia is observed over more than 48 weeks without the emergence of resistance, RAL should never be given as functional monotherapy, as it is associated with a maximal risk of VF and the emergence of RAL resistance.

The older HIV-positive adult: a critical review of the medical literature

Older adults make up an ever-growing proportion of human immunodeficiency virus (HIV) cases in the United States, with approximately 25% of infections occurring in adults over the age of 50 years. Although there is a preliminary body of literature addressing the socioeconomic and prognostic issues of HIV infection in older adults, very little rigorous scientific research has looked at the significant clinical issues relevant to this growing population. Treatment of older adults is complicated by an increased prevalence of medical comorbidities, but little is known about the effects of complicated medication regimens in this group, as they are routinely excluded from clinical trials of newer HIV medications. The delay in diagnosis and treatment of HIV in older adults has led to poorer outcomes, including lower baseline CD4 counts, decreased time to acquired immune deficiency syndrome diagnosis, and increased mortality. Despite these facts, there is mounting evidence that timely diagnosis and treatment of HIV in older adults leads to improved outcomes, similar to younger patients. This review evaluates the literature focusing on HIV and older adults.

CD4 immunophenotyping in HIV infection

The ability to rapidly identify immune cell subsets such as CD4 cells, which became possible around the same time as the onset of the HIV/AIDS pandemic, was one of the greatest advances in clinical and diagnostic immunology. The evolution of this global pandemic and the subsequent development of treatment strategies to prolong the life of infected individuals mean that it is now more crucial than ever that we develop affordable, reliable and accurate methods for the enumeration of CD4 cells. Here, we provide an overview of the historical developments in CD4 enumeration technologies that are related to HIV infection, and summarize the current technological challenges that must be overcome to meet the needs of those living with HIV infection.

Efficacy and safety of 48 weeks of enfuvirtide 180 mg once-daily dosing versus 90 mg twice-daily dosing in HIV-infected patients

PURPOSE

To evaluate the safety and antiviral activity of once-daily (qd) enfuvirtide (ENF) compared with twice daily (bid) ENF.

METHOD

T20-401 was a phase 2, open-label, randomized, 48-week pilot study comparing ENF 180 mg qd versus ENF 90 mg bid, added to an optimized background (OB) regimen. Patients were randomized 1:1 to receive ENF 180 mg qd given as two 90-mg injections (n = 30) or one 90-mg injection bid (n = 31), plus OB. The primary efficacy endpoint was the proportion of patients achieving a HIV-1 RNA viral load <400 copies/mL. Adherence, pharmacokinetics, safety, and tolerability parameters, including injection site reactions (ISRs), were compared between treatment arms.

RESULTS

At Week 48, 23.3% of patients on once daily versus 22.6% on twice daily (p = .969) reached <400 copies/mL and 13.3% and 22.6% (p = .323), respectively, reached <50 copies/mL. The proportion reporting 1 adverse event or ISRs was comparable between arms, despite an increased incidence of grade 4 erythema (13% vs. 0%), induration (33% vs. 12%), and ecchymosis (7% vs. 0%) on twice daily versus once daily. ENF adherence (95% of prescribed doses) was higher on once daily (80.0%) versus twice daily (58.1%).

CONCLUSION

The antiviral efficacy, safety, and tolerability of 180 mg ENF qd appeared comparable with that of 90 mg ENF bid at Week 48, although the study was not powered to demonstrate the noninferiority of once daily versus twice daily.

The cost-effectiveness of counseling strategies to improve adherence to highly active antiretroviral therapy among men who have sex with men

OBJECTIVE

Inadequate adherence to highly active antiretroviral therapy (HAART) may lead to poor health outcomes and the development of HIV strains that are resistant to HAART. The authors developed a model to evaluate the cost-effectiveness of counseling interventions to improve adherence to HAART among men who have sex with men (MSM).

METHODS

The authors developed a dynamic compartmental model that incorporates HIV treatment, adherence to treatment, and infection transmission and progression. All data estimates were obtained from secondary sources. The authors evaluated a counseling intervention given prior to initiation of HAART and before all changes in drug regimens, combined with phone-in support while on HAART. They considered a moderate-prevalence and a high-prevalence population of MSM.

RESULTS

If the impact of HIV transmission is ignored, the counseling intervention has a cost-effectiveness ratio of $25,500 per quality-adjusted life year (QALY) gained. When HIV transmission is included, the cost-effectiveness ratio is much lower: $7400 and $8700 per QALY gained in the moderate- and high-prevalence populations, respectively. When the intervention is twice as costly per counseling session and half as effective as estimated in the base case (in terms of the number of individuals who become highly adherent, and who remain highly adherent), then the intervention costs $17,100 and $19,600 per QALY gained in the 2 populations, respectively.

CONCLUSIONS

Counseling to improve adherence to HAART increased length of life, modestly reduced HIV transmission, and cost substantially less than $50,000 per QALY gained over a wide range of assumptions but did not reduce the proportion of drug-resistant strains. Such counseling provides only modest benefit as a tool for HIV prevention but can provide significant benefit for individual patients at an affordable cost.

Cost-effectiveness of alternative strategies for initiating and monitoring highly active antiretroviral therapy in the developing world

OBJECTIVE

Determine the cost-effectiveness of initiating and monitoring highly active antiretroviral therapy (HAART) in developing countries according to developing world versus developed world guidelines.

DESIGN

Lifetime Markov model incorporating costs, quality of life, survival, and transmission to sexual contacts.

METHODS

We evaluated treating patients with HIV in South Africa according to World Health Organization (WHO) "3 by 5" guidelines (treat CD4 counts <or=200 cells/mm or patients with AIDS, and monitor CD4 cell counts every 6 months) versus modified WHO guidelines that incorporate the following key differences from developed world guidelines: treat CD4 counts <or=350 cells/mm or viral loads >100,000 copies/mL, and monitor CD4 cell counts and viral load every 3 months.

RESULTS

Incorporating transmission to partners (excluding indirect costs), treating patients according to developed versus developing world guidelines increased costs by US $11,867 and increased life expectancy by 3.00 quality-adjusted life-years (QALYs), for an incremental cost-effectiveness of $3956 per QALY. Including indirect costs, over the duration of the model, there are net cost savings to the economy of $39.4 billion, with increased direct medical costs of $60.5 billion offset by indirect cost savings of $99.9 billion.

CONCLUSIONS

Treating patients with HIV according to developed versus developing world guidelines is highly cost-effective and may result in substantial long-term savings.

Predictors of failure of first-line antiretroviral therapy in HIV-infected adults: Indian experience

OBJECTIVES

To study the incidence and risk factors for failure of treatment with antiretroviral therapy among adults in the national treatment program in India, and to estimate the possible number of persons living with human immunodeficiency virus (HIV) who will need a second-line treatment regimen in the next 3 and 3.5 years.

DESIGN AND SETTING

Data of a cohort of HIV-positive adult patients, who were enrolled in the government-sponsored antiretroviral therapy program, were obtained from the electronic medical record system of the largest HIV care center in India and subjected to analysis.

MAIN OUTCOMES

Treatment failure defined by the World Health Organization criteria, assessed immunologically on the basis of CD4 T cell count, with a minimum period of 12 months of follow-up and with a minimum of two CD4 T cell follow-up measures.

RESULTS

The cumulative incidence of treatment failure in the 1370 adult patients included in the study was 3.9% (95% confidence interval [CI] 2.9 to 4.9). Men had a 3.5 (1.6 to 7.4) times significantly greater risk of treatment failure. Patients who had negative changes in absolute lymphocyte count, hemoglobin concentration and body weight had 3.1 (1.6 to 6.2), 3.2 (1.6 to 6.2), and 3.5 (1.9 to 6.4) times significantly greater risk of treatment failure. In India, after 2007, by 2, 3, and 3.5 years, respectively, an estimated 16 000, 35 000, and 51 000 patients receiving antiretroviral therapy are likely to require second-line treatment.

CONCLUSION

Monitoring of hemoglobin concentration, absolute lymphocyte count, and body weight during follow-up emerged as inexpensive predictors of treatment failure in a resource-poor setting. A significant number of patients will need second-line therapy as a result of failure of their first-line antiretroviral therapy regimen in 3 and 3.5 years in India, and therefore the development of an appropriate policy for second-line drugs is urgently needed.

Adherence to generic reverse transcriptase inhibitor-based antiretroviral medication at a Tertiary Center in North India

At least 95% adherence to medications is required for sustained response to antiretroviral therapy (ART). In resource constraint restrained settings it is not possible to use electronic methods to determine adherence. We determined adherence during the previous 4 weeks by the recall method in 200 patients (138 males) receiving generic triple drug reverse transcriptase inhibitor-based antiretroviral medications. They were administered a uniform questionnaire to determine the number of time they forgot or were unable to take their medications and the reasons thereof. One hundred and fifty received two and 50 took three pills daily. One hundred and forty-seven did not miss any dose. Fifty-three (26.5%) missed at least one dose during the preceding 4 weeks. Thirty-one took treatment on and off. Seven missed a dose in the preceding 3 days, nine more between the last 3 and 7 days, and six from 1 to 4 weeks. The major reasons for non-adherence were financial constraints, forgetting to take the medication, drug toxicity, lack of access to the drug, fear of getting immune to the benefit of the drug, and to avoid adverse effects. Non-adherence in 26.5% individuals could be an additional factor that can increase the risk of drug resistance.

Pharmacokinetic Bioequivalence of Enfuvirtide Using a Needle-Free Device versus Standard Needle Administration

STUDY OBJECTIVES

To compare the relative bioavailability of enfuvirtide, a human immunodeficiency virus type 1 (HIV-1) fusion inhibitor, injected with the Biojector 2000 (B2000) needle-free device versus a 27-gauge half-inch needle-syringe; and to assess safety, tolerability, and patient preference for the two devices.

DESIGN

Open-label, randomized, two-period crossover bioequivalence evaluation.

SETTING

Clinical research center.

PATIENTS

Twenty-seven adults with HIV-1 viral loads below 1000 copies/ml.

INTERVENTION

Each patient received enfuvirtide 90 mg subcutaneously with the B2000 and with the needle-syringe, with a 1-week washout between treatments.

MEASUREMENTS AND MAIN RESULTS

Twenty-six and 27 patients were included in the bioequivalence and safety analyses, respectively. Plasma enfuvirtide concentrations were measured at baseline and at several intervals after each injection. The B2000:needle-syringe ratios of maximum concentration (C(max)), area under the concentration-time curve from time zero extrapolated to infinity (AUC(0-infinity)), and AUC from time zero to tau (dosing interval) (AUC(0-tau)) served as criteria for bioequivalence determination. The two drug delivery systems were considered bioequivalent if the 90% confidence intervals (CIs) for the ratios were within 0.8-1.25. Safety and tolerability were evaluated based on documentation of adverse events, graded laboratory toxicities, and local injection-site reactions. Patient surveys provided feedback on device preference. Ratios of C(max), AUC(0-infinity), and AUC(0-tau) were 0.95 (90% CI 0.84-1.09), 0.99 (90% CI 0.93-1.05), and 0.99 (90% CI 0.93-1.05), respectively. The frequency of injection-site reactions was low, and severity was generally mild for both devices. Survey results showed 18 patients (69%) had a positive overall impression of the B2000 and 14 (54%) felt safer injecting with this device. Overall, 17 patients (65%) preferred the B2000 over the needle-syringe.

CONCLUSION

Bioavailability of enfuvirtide with the B2000 and needle-syringe was equivalent based on C(max), AUC(0-tau), and AUC(0-infinity). Safety profiles and injection-site reactions were comparable between the devices, but patients preferred the B2000. Delivery of enfuvirtide with the B2000 is a feasible alternative to standard needle administration and warrants further evaluation.

Potential Impact of Antiretroviral Therapy on HIV-1 Transmission and AIDS Mortality in Resource-Limited Settings

OBJECTIVE

To estimate the potential impact of antiretroviral therapy on the heterosexual spread of HIV-1 infection and AIDS mortality in resource-limited settings.

METHODS

A mathematic model of HIV-1 disease progression and transmission was used to assess epidemiologic outcomes under different scenarios of antiretroviral therapy, including implementation of World Health Organization guidelines.

RESULTS

Implementing antiretroviral therapy at 5% HIV-1 prevalence and administering it to 100% of AIDS cases are predicted to decrease new HIV-1 infections and cumulative deaths from AIDS after 10 years by 11.2% (inter-quartile range [IQR]: 1.8%-21.4%) and 33.4% (IQR: 26%-42.8%), respectively. Later implementation of therapy at endemic equilibrium (40% prevalence) is predicted to be less effective, decreasing new HIV-1 infections and cumulative deaths from AIDS by 10.5% (IQR: 2.6%-19.3%) and 27.6% (IQR: 20.8%-36.8%), respectively. Therapy is predicted to benefit the infected individual and the uninfected community by decreasing transmission and AIDS deaths. The community benefit is greater than the individual benefit after 25 years of treatment and increases with the proportion of AIDS cases treated.

CONCLUSIONS

Antiretroviral therapy is predicted to have individual and public health benefits that increase with time and the proportion of infected persons treated. The impact of therapy is greater when introduced earlier in an epidemic, but the benefit can be lost by residual infectivity or disease progression on treatment and by sexual disinhibition of the general population.

Pharmacokinetics, pharmacodynamics and safety of once-daily versus twice-daily dosing with enfuvirtide in HIV-infected subjects

OBJECTIVE

To investigate the pharmacokinetics, safety/tolerability and antiviral activity of enfuvirtide administered once-daily (QD) versus twice-daily (BID).

DESIGN

An open-label, randomized, multiple dose, two-period crossover study comparing 180 mg enfuvirtide, two injections QD versus 90 mg enfuvirtide, two injections, BID.

METHODS

Steady-state intensive pharmacokinetic samples were obtained on days 7 and 14.

RESULTS

Thirty-seven subjects received at least one dose of enfuvirtide. Thirty-three subjects completed both dosing periods. The regimens were bioequivalent based on the ratio of geometric mean area under the curve (AUC)0-tau [112 +/- 6.2 microg x h/ml QD; 115 +/- 6.4 microg x h/ml 2 x BID; QD/BID 0.98; 90% confidence interval (CI) 0.89,1.07]. The maximum observed plasma concentration within a dosing interval (Cmax) was 49% higher for QD (9.5 +/- 2.7 microg/ml) versus BID (6.3 +/- 1.7 microg/ml) and the pre-dose plasma concentration (Ctrough) was 57% lower for QD (1.6 +/- 1.1 microg/ml) versus BID (3.8 +/- 1.3 microg/ml). The LSM decrease in viral load from baseline to day 7 was 1.0 +/- 0.14 log10 (n = 18) for QD and 1.4 +/- 0.2 log10 (n = 17) for BID (LSM difference 0.385; P = 0.07). Linear regression analysis suggested that decline in viral load up to day 7 was associated with Ctrough but not Cmax or AUC. There were no significant differences in adverse events between the two dosing regimens.

CONCLUSIONS

Administration of enfuvirtide 180 mg QD results in bioequivalence compared with 90 mg BID based on AUC with a similar short-term safety profile, but a trend towards a weaker antiretroviral effect. Larger and longer-term studies are needed to determine if 180 mg once daily is an effective dosing alternative for enfuvirtide.

Approaches to antiretroviral therapy in China

China has recognized the threat of HIV to its population and responded with a national antiretroviral treatment (ART) program. However, high ART failure rates and the spread of resistance within populations are important realities to consider when developing and managing ART programs in China and worldwide. Concepts which will define treatment success and local and national programmatic goals are 1) access to ART, 2) durability of ART at the patient level, 3) scalability of treatment modalities, and the 4) sustainability of the program at the community or national level. In the face of limited resources, China must also consider when to start ARV therapy, which agents to use, when to switch them, and how to treat highly experienced patients with drug resistance. The optimal ARV regimen to start with is changing frequently with the introduction of new agents and the presentation of new data. Currently, a regimen including tenofovir, emtricitabine or lamivudine and a nonnucleoside reverse transcriptase inhibitor appears to have optimal characteristics to treat HIV/AIDS in China. However, critical to all of these choices is the evaluation of programs implemented to insure wide scale success. China has wisely begun this process of evaluating the performance of local programs through systematic monitoring and evaluation of treatment outcomes. This will allow regimens and programs that work to be expanded, and programs with high failure rates to be eliminated. In the end, evidence based data supporting treatment strategies will allow China to successfully confront its AIDS epidemic early and prevent its tragic consequences.

Virologic and immunologic response to highly active antiretroviral therapy

Highly active antiretroviral therapy (HAART) delays clinical progression by suppressing viral replication, measured by a substantial reduction in HIV RNA, allowing the immune system to reconstitute, measured in most studies by an increase in CD4 cells. 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 receiving HAART. In this report, we review studies describing the heterogeneous virologic and immunologic progression after the initiation of HAART, discuss methodologic concerns in the study of the response of biomarkers, and update findings obtained in the Multicenter AIDS Cohort Study, which show that CD4 cell count, history of antiretroviral therapy, and age at the time of initiation are independent determinants of response.

Cost-effectiveness of screening for HIV in the era of highly active antiretroviral therapy

BACKGROUND

The costs, benefits, and cost-effectiveness of screening for human immunodeficiency virus (HIV) in health care settings during the era of highly active antiretroviral therapy (HAART) have not been determined.

METHODS

We developed a Markov model of costs, quality of life, and survival associated with an HIV-screening program as compared with current practice. In both strategies, symptomatic patients were identified through symptom-based case finding. Identified patients started treatment when their CD4 count dropped to 350 cells per cubic millimeter. Disease progression was defined on the basis of CD4 levels and viral load. The likelihood of sexual transmission was based on viral load, knowledge of HIV status, and efficacy of counseling.

RESULTS

Given a 1 percent prevalence of unidentified HIV infection, screening increased life expectancy by 5.48 days, or 4.70 quality-adjusted days, at an estimated cost of 194 dollars per screened patient, for a cost-effectiveness ratio of 15,078 dollars per quality-adjusted life-year. Screening cost less than 50,000 dollars per quality-adjusted life-year if the prevalence of unidentified HIV infection exceeded 0.05 percent. Excluding HIV transmission, the cost-effectiveness of screening was 41,736 dollars per quality-adjusted life-year. Screening every five years, as compared with a one-time screening program, cost 57,138 dollars per quality-adjusted life-year, but was more attractive in settings with a high incidence of infection. Our results were sensitive to the efficacy of behavior modification, the benefit of early identification and therapy, and the prevalence and incidence of HIV infection.

CONCLUSIONS

The cost-effectiveness of routine HIV screening in health care settings, even in relatively low-prevalence populations, is similar to that of commonly accepted interventions, and such programs should be expanded.

Steady-state pharmacokinetics of a double-boosting regimen of saquinavir soft gel plus lopinavir plus minidose ritonavir in human immunodeficiency virus-infected adults

Management of treatment-experienced human immunodeficiency virus patients has become complex, and therapy may need to include two protease inhibitors at therapeutic doses. The objective of this study was to characterize the pharmacokinetics in serum of saquinavir (1,000 mg twice daily [b.i.d.]), lopinavir (400 mg b.i.d.), and ritonavir (100 mg b.i.d.) in a multidrug rescue therapy study and to investigate whether steady-state pharmacokinetics of lopinavir-ritonavir are affected by coadministration of saquinavir. Forty patients were included (25 given ritonavir, lopinavir, and saquinavir and 15 given ritonavir and lopinavir). The median pharmacokinetic parameters of lopinavir were as follows: area under the concentration-time curve from 0 to 12 h (AUC(0-12)), 85.1 microg/ml . h; maximum concentration of drug in serum (C(max)), 10.0 microg/ml; trough concentration of drug in serum (C(trough)), 7.3 microg/ml; and minimum concentration of drug in serum (C(min)), 5.5 microg/ml. Lopinavir concentrations were similar in patients with and without saquinavir. The median pharmacokinetic parameters for saquinavir were as follows: AUC(0-12), 22.9 microg/ml . h; C(max), 2.9 microg/ml; C(trough), 1.6 microg/ml; and C(min), 1.4 microg/ml. There was a strong linear correlation between lopinavir and ritonavir and between saquinavir and ritonavir concentrations in plasma. The correlation between lopinavir and saquinavir levels was weaker. We found higher saquinavir concentrations in women than in men, with no difference in lopinavir levels. Only patients with very high body weight presented lopinavir and saquinavir concentrations lower than the overall group. Ritonavir has a double-boosting function for both lopinavir and saquinavir, and in terms of pharmacokinetics, the drug doses selected seemed appropriate for combining these agents in a dual protease inhibitor-based antiretroviral regimen for patients with several prior virologic failures.

Clinical, immunological and virological evolution in patients with CD4 T-cell count above 500/mm3: is there a benefit to treat with highly active antiretroviral therapy (HAART)?

To assess the clinical, immunological and virological evolution in HIV-1 infected patients with CD4 T-cell count above 500/mm3, a historical cohort of 202 untreated and 96 patients treated with HAART was longitudinally studied (median follow-up 36 months). Fourteen untreated and 2 treated patients experienced clinical progression (p = 0.09). The difference between baseline CD4 T-cell count and after 3 years, was -240/mm3 in the untreated group +19/mm3 in the HAART group (p < 10(-3)). A better immunological outcome was significantly associated with a HIV sexual contamination (p = 0.01), HAART (p = 0.01), high baseline CD4 T-cell count (p < 10(-3)) and low baseline HIV viral load (p = 0.01). In the HAART group, the incidence rate of antiretroviral modification due to tolerance difficulties was 0.23+/-0.36/patient year. A sustained undetectable HIV viral load was correlated with a low baseline HIV viral load (p = 0.003) and to be antiretroviral naive (p < 10(-3)). Thus, HAART provide a better immunological outcome in patients with high CD4 T-cell count. However, the CD4 decay slope after 3 years, the risk of therapeutic side-effects and the low risk of clinical progression do not support systematic treatment of those patients.

Update on the Virologic and Immunologic Response to Highly Active Antiretroviral Therapy

Highly active antiretroviral therapy (HAART) delays clinical progression by suppressing viral replication, measured by a substantial reduction in HIV RNA, allowing the immune system to reconstitute, measured in most studies by an increase in CD4 cells. 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 receiving HAART. In this report, we review studies describing the heterogeneous virologic and immunologic progression after the initiation of HAART, discuss methodologic concerns in the study of the response of biomarkers, and update findings obtained in the Multicenter AIDS Cohort Study, which show that CD4 cell count, history of antiretroviral therapy, and age at the time of initiation are independent determinants of response.

Long-Term Virological Response to Multiple Sequential Regimens of Highly Active Antiretroviral Therapy for HIV Infection

Objective

Information about the virological response to sequential highly active antiretroviral therapy (HAART) for HIV infection is limited. The virological response to four consecutive therapies was evaluated in the Swiss HIV Cohort.

Design

Retrospective analysis in an observational cohort.

Methods

1140 individuals receiving uninterrupted HAART for 4.8 ±0.6 years were included. The virological response was classified as success (<400 copies/ml), low-level (LF: 400–5000 copies/ml) or high-level failure (HF: >5000 copies/ml). Potential determinants of the virological response, including patient demographics, treatment history and virological response to previous HAART regimens were analysed using survival and logistic regression analyses.

Results

40.1% failed virologically on the first (22.0% LF; 18.1% HF), 35.1% on the second (14.2% LF; 20.9% HF), 34.2% on the third (9.9% LF; 24.3% HF) and 32.7% on the fourth HAART regimen (9% LF; 23.7% HF). Nucleoside pre-treatment (OR: 2.34; 95% CI: 1.67–3.29) and low baseline CD4 T-cell count (OR: 0.79/100 cells rise; 95% CI: 0.72–0.88) increased the risk of HF on the first HAART. Virological failure on HAART with HIV-1 RNA levels exceeding 1000 copies/ml predicted a poor virological response to subsequent HAART regimens. A switch from a protease inhibitor- to a non-nucleoside reverse transcriptase inhibitor-containing regimen significantly reduced the risk of HF. Multiple switches of HAART did not affect the recovery of CD4 T lymphocytes.

Conclusion

Multiple sequential HAART regimens do not per se reduce the likelihood of long-term virological suppression and immunological recovery. However, early virological failure increases significantly the risk of subsequent unfavourable virological responses. The choice of a potent initial antiretroviral drug regimen is therefore critical. This study has been presented in part at the 10th Conference on Retroviruses & Opportunistic Infections. Boston, Mass., USA, 2003. Abstract #571.

Use of the protease inhibitor saquinavir hard gel in human immunodeficiency virus-infected patients in the early period of highly active antiretroviral therapy: does it affect long-term treatment outcome?

Saquinavir hard gel capsule (hgc), the first human immunodeficiency virus (HIV) protease inhibitor (PI) used in clinical practice, has been shown to have insufficient effectiveness. A population-based cohort study assessed the long-term consequences of using saquinavir hgc as initial PI in HIV-infected patients pre-exposed to nucleoside reverse transcriptase inhibitors. 121 patients starting a regimen with saquinavir hgc were compared with 91 starting with non-boosted indinavir (n = 72) or ritonavir (n = 19). Median follow-up time was 4.6 and 4.7 y for the 2 groups. Starting with saquinavir hgc was associated with a lower overall probability of achieving an undetectable viral load [risk ratio (RR) = 0.41, 95%, confidence interval (95% CI) 0.30-0.56]. However, the lower probability of having undetectable viral load during follow-up declined over time with odds ratios (OR) = 0.27 (95%, CI 0.14-0.54), 0.35 (951% CI 0.19-0.66), 0.47 (95% CI 0.24-0.91) and 0.73 (95% CI 0.34-1.55) at 60, 120, 180 and 240 weeks, respectively, after starting HAART. Starting with saquinavir hgc was correlated with a higher risk of having the initial PI discontinued (RR = 1.89, 95% CI 1.39-2.58). The insufficient suppression of viral load in patients starting with saquinavir hgc subsided during follow-up, probably owing to the earlier discontinuation of saquinavir hcg in favour of newer and more potent HAART regimens.

Response to highly active antiretroviral therapy strongly predicts outcome in patients with AIDS-related lymphoma

BACKGROUND

AIDS-related lymphoma (ARL) remains a frequent complication of HIV infection. We analyzed the outcome of patients with ARL with respect to the use and efficacy of highly active antiretroviral therapy (HAART) and to potential prognostic factors.

METHODS

This multicenter cohort study included patients with systemic ARL diagnosed between 1990-2001. We evaluated overall survival and the effects of several variables on overall survival using the Kaplan-Meier method and the extended Cox proportional hazards model. Response to HAART was used as a time-dependent variable and was defined as a CD4 cell count increase of >/= 100 x 106 cells/l and/or at least one viral load < 500 copies/ml during the first 2 years following diagnosis of ARL.

RESULTS

Among 203 patients with ARL, median overall survival was 9.0 months [95% confidence interval (CI), 7.6-12.4 months]. In the univariate analyses, age < 60 years, no previous AIDS, CD4 cell counts >/= 200 x 106 cells/l, hemoglobin > 11 g/dl, Ann Arbor stages I-II and A, no extranodal lesion, response to HAART, and complete remission showed statistically significant association with prolonged overall survival. In the multivariate Cox model, the only factors independently associated with overall survival were response to HAART [relative hazard (RH), 0.32; 95% CI, 0.16-0.62], complete remission (RH, 0.24; 95% CI, 0.15-0.36), previous AIDS (RH, 1.92; 95%CI, 1.23-3.01) and extranodal involvement (RH, 2.85; 95% CI, 1.47-5.51).

CONCLUSIONS

Efficacy of HAART was independently associated with prolonged survival in this large cohort of patients with ARL. Information on patient's response to HAART is crucial for the evaluation of future treatment strategies.

Survival in an urban HIV-1 clinic in the era of highly active antiretroviral therapy: a 5-year cohort study

OBJECTIVE

To examine the implications of early virologic response to highly active antiretroviral therapy (HAART) on long-term HAART utilization patterns, development of diabetes or hyperlipidemia, and mortality in an urban HIV-1 clinic.

DESIGN

A cohort of 444 patients in an urban HIV-1 clinic, who started HAART prior to January 1, 1999, were categorized by virologic response in the first 18 months of therapy: durable viral suppression, initial suppression followed by rebound, and failure to achieve suppression. Antiretroviral exposure, HIV-1 RNA levels, CD4 cell counts, development of diabetes or hyperlipidemia, and survival were compared in the three groups.

RESULTS

Over 4 years of follow-up, patients in the durable suppression group used HAART 82% of the time compared with 60% in the rebound group (p <.001) and 23% in the failure to suppress group (p <.001). Through 4 years of follow-up, patients in the rebound group had a cumulative exposure to a median of seven antiretroviral drugs (interquartile range [IQR]: 6-9) compared with five drugs in the durable suppression group (IQR: 4-6) and five drugs in the failure to suppress group (IQR: 3-7) (p <.001 for both comparisons with the rebound group). At 5 years, the estimated proportions surviving were 89% in the durable suppression group, 76% in the rebound group (p =.04), and 56% in the failure to suppress group (p <.001). During follow-up, 35% in the durable suppression group developed diabetes or hyperlipidemia compared with 24% in the rebound group (p =.15) and 8% in the failure to suppress group (p <.001).

CONCLUSIONS

This study highlights the long-term implications of early virologic response to HAART for survival, accumulation of triple-class antiretroviral exposure, and development of HAART-associated toxicities.

Pharmacokinetic-pharmacodynamic analysis of lopinavir-ritonavir in combination with efavirenz and two nucleoside reverse transcriptase inhibitors in extensively pretreated human immunodeficiency virus-infected patients

The steady-state pharmacokinetics and pharmacodynamics of two oral doses of lopinavir-ritonavir (lopinavir/r; 400/100 and 533/133 mg) twice daily (BID) when dosed in combination with efavirenz, plus two nucleoside reverse transcriptase inhibitors, were assessed in a phase II, open-label, randomized, parallel arm study in 57 multiple protease inhibitor-experienced but non-nucleoside reverse transcriptase inhibitor-naive human immunodeficiency virus (HIV)-infected subjects. All subjects began dosing of lopinavir/r at 400/100 mg BID; subjects in one arm increased the lopinavir/r dose to 533/133 mg BID on day 14. When codosed with efavirenz, the lopinavir/r 400/100 mg BID regimen resulted in lower lopinavir concentrations in plasma, particularly C(min), than were observed in previous studies of lopinavir/r administered without efavirenz. Increasing the lopinavir/r dose to 533/133 mg increased the lopinavir area under the concentration-time curve over a 12-h dosing interval (AUC(12)), C(predose), and C(min) by 46, 70, and 141%, respectively. The increase in lopinavir C(max) (33%,) did not reach statistical significance. Ritonavir AUC(12), C(max), C(predose), and C(min) values were increased 46 to 63%. The lopinavir predose concentrations achieved with the 533/133-mg BID dose were similar to those observed with lopinavir/r 400/100 mg BID in the absence of efavirenz. Results from univariate logistic regression analyses identified lopinavir and efavirenz inhibitory quotient (IQ) parameters, as well as the baseline lopinavir phenotypic susceptibility, as predictors of antiviral response (HIV RNA < 400 copies/ml at week 24); however, no lopinavir or efavirenz concentration parameter was identified as a predictor. Multiple stepwise logistic regressions confirmed the significance of the IQ parameters, as well as other baseline characteristics, in predicting virologic response at 24 weeks in this patient population.

Overcoming resistance: virologic response to a salvage regimen with the combination of ritonavir plus indinavir

PURPOSE

To explore the possibility of overcoming resistance to protease inhibitors (PIs) and to determine the resistance cutoff values that continue to predict treatment failure with a dual PI regimen.

METHOD

We performed a prospective study of 53 patients who had failed in several PIs and who were included in a ritonavir (RTV) plus indinavir (IDV) salvage regimen. Median HIV RNA level decrease was evaluated according to resistance assays and indinavir trough levels.

RESULTS

Eighty-seven percent of patients had previously failed on an IDV-containing regimen. Overall, median HIV RNA decrease was -1.25 log(10) copies/mL after 3 months on therapy. A significant blunted virologic response was observed only in isolates with more than 12 substitutions including the V82A (-0.75 vs. -1.3 log(10) copies/mL; p =.04), or in isolates with more than 30 fold-increase in the IC(50) (-0.43 vs. -1.2 log(10) copies/mL). Higher drug levels were observed in patients with resistant isolates who achieved an HIV RNA decrease greater than 1 log (1742 vs. 1100 ng/mL).

CONCLUSION

Our preliminary data suggest the possibility of overcoming resistance with the combination of RTV plus IDV. They also suggest the need for establishing new resistance cutoff values when using PIs in combination.

HIV disease and advanced age: an increasing therapeutic challenge

The mean age of patients at both first HIV detection and AIDS diagnosis is progressively rising over time. However, reliable epidemiological estimates, clinical data or controlled therapeutic and outcome figures are lacking for elderly patients, especially with regard to laboratory and clinical response to antiretroviral therapy, treatment tolerability, drug-drug interactions, short- and long-term toxicity, and interactions with underlying illnesses and concurrent pharmacological treatment. In fact, the large majority of randomised, controlled trials evaluating and comparing new antiretroviral drugs or anti-HIV therapeutic strategies, as well as antimicrobial treatment or chemoprophylaxis of HIV-related complications, either excluded patients with advanced age and/or concurrent disorders or did not offer substudies or detailed data analysis focusing on older patients compared with younger ones. The life expectancy of HIV-infected persons receiving highly active antiretroviral therapy (HAART) is now extended (approaching that of the general population), so that the definition of AIDS has lost its epidemiological and clinical significance thanks to the immune reconstitution resulting from potent antiretroviral therapy. However, an ever-increasing number of individuals aged > or =50 years with HIV infection is expected in the coming years, as a result of both increased survival of patients with treated disease and delayed recognition of individuals with occult HIV disease. The limited data available about combined antiretroviral therapy in the elderly seem to show an overlapping virological success rate but a slower and blunted immune recovery compared with younger patients. Thymic output, however, seems somewhat preserved even in adulthood and may contribute to the reconstitution of most of the quantitative and functional T cell abnormalities caused by HIV disease. More attention must be paid to underlying end-organ disorders, as well as expected pharmacological interactions and combined drug toxicity that may interfere with HAART efficacy and patients' compliance with recommended regimens and could lead to increased adverse effects. The available guidelines for antiretroviral treatment and therapy and prophylaxis of AIDS-related illnesses should be regularly updated and should include problems related to HIV disease in an aging population. Specific trials or substudies focusing on older people are warranted to obtain controlled data on all issues of antiretroviral therapy in the elderly, including time and mode of initiation, and modification and salvage HAART regimens. Antiretroviral drug dosage adjustment to take into account underlying pathological conditions or other pharmacological treatments is another emerging issue.

[Adherence to antiretroviral therapy measured by pill count and drug serum concentrations. Variables associated with a bad adherence]

BACKGROUND

We aimed at measuring the adherence to HAART by means of pill count and drug plasma levels. In addition, we aimed at determining variables associated with suboptimal adherence.

PATIENTS AND METHOD

Prospective observational study of 202 consecutive patients with HIV infection who were receiving antiretroviral treatment, followed up during 9 months. At baseline and at the end of the study a structured questionnaire was administered and a review of medical charts was performed. The adherence was assessed by monthly pill count while drug plasma levels were measured every three months. We considered that a patient adherence was not fulfilled when the mean pill count was < 90% or when any plasma drug level was lower than that expected.

RESULTS

Of 143 available patients, 41.2% were non-adherent. According to the univariate analysis, non-adherent patients were more likely to be younger, female, under a methadone maintenance scheme, under psychiatric treatment, to have depression (according to the Beck Depression Inventory), to have adverse antiretroviral effects and to have a previous history of voluntary withdrawal of the treatment. Men who had sex with other men were significantly more adherent. In the multivariate analysis, female sex [OR 2.6 (1.04-6.65)], to be under a methadone program [OR 9.43 (1.01-88)], to have adverse drug effects [OR 2.63 (1.09-6.33)] and to have a previous history of voluntary withdrawal [OR 2.63 (1.09-6.36)] were independent risk factors for non-adherence.

CONCLUSIONS

Adherence to antiretroviral therapy was 58.8%, similar to that seen in other chronic diseases. To be under a methadone maintenance program and having an active drug addiction was related with non-adherence. Women with worst adherence levels had frequently psychiatric comorbidity and more adverse drug effects.

Phenotype or Virtual Phenotype for Choosing Antiretroviral Therapy after Failure: A Prospective, Randomized Study

Background

Resistance testing is useful in the management of virological failure patients, although the best method to be used in clinical practice has not been determined.

Methods

A prospective, randomized, double-blind, multicentre, controlled clinical trial was performed to compare the usefulness of drug resistance testing with a recombinant viral phenotype method or with a virtual phenotype, a genotyping interpretation system. Planned 300 HIV-infected adults failing their current antiretroviral therapy (HIV RNA >1000 copies/ml) were centrally randomized 1:1 to resistance testing with a recombinant viral phenotype method or with a virtual phenotype, after stratifying according to previous drug exposure (one or two versus three drug classes). Percent of patients with HIV RNA suppression (% <400 copies/ml) after 24 weeks was the primary outcome variable. Median HIV RNA concentration and change from baseline in HIV RNA concentration were also used to compare effectiveness. An extended analysis was performed at week 48.

Results

Of the 300 patients enrolled, a total of 276 patients could be analysed; 139 patients were randomized to the phenotype group and 137 patients were randomized to the virtual phenotype group. After 24 weeks of follow-up, 46.8 and 56.2% of patients had HIV RNA <400 copies/ml ( P=0.1) in the phenotype and virtual phenotype, respectively. Mean decrease from baseline in viral load was 1.0 and 1.3 log copies/ml in the phenotype and virtual phenotype groups, respectively ( P=0.017). In a multivariate linear regression analysis, after adjusting for baseline HIV RNA and adherence to treatment, the virtual phenotype was associated with a greater mean decrease in plasma HIV RNA ( P=0.0063). The results observed at week 48 were similar.

Conclusions

Virtual phenotype is at least as effective as phenotype when used to select an optimized treatment for patients who have failed one or more antiretroviral regimens.

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.

Impact of discontinuation of initial protease inhibitor therapy on further virological response in a cohort of human immunodeficiency virus-infected patients

Although discontinuation of antiretroviral drug therapy is common, the impact on outcome in routine clinical practice is unknown. The Antiprotéases Cohorte (APROCO) Cohort Study enrolled 1281 patients at the time they started a protease inhibitor (PI)-containing regimen from 1997 through 1999. After a median duration of follow-up of 20 months, 51% of patients had discontinued their initial PI. Prospectively recorded reasons for discontinuation were intolerance (52% of patients), poor adherence (22%), and failure of therapy (15%). In a multivariate logistic regression analysis, only discontinuation due to poor adherence was associated with a lower frequency of human immunodeficiency virus RNA level in plasma of <500 copies/mL 12 months after initiation of therapy (odds ratio, 0.27 vs. no change; P<.0001); discontinuation due to intolerance was not associated with virological response (odds ratio, 0.89; P=.58). Patients experiencing intolerance should be reassured that changing therapy will probably not be harmful. Multidisciplinary efforts should concentrate on ways to avoid discontinuation of treatment for adherence reasons.

Highly active antiretroviral therapy-associated regression of cytomegalovirus retinitis: long-Term results in a small case series

PURPOSE

To report the stability of acquired immunodeficiency syndrome (AIDS)-associated cytomegalovirus (CMV) retinitis lesions that have undergone regression in the absence of specific anti-CMV medications owing to highly active antiretroviral therapy (HAART)-generated immune recovery.

METHODS

The initial examination revealed HAART-associated regression of CMV retinitis lesions in eight subjects at two institutions. Patients were monitored for recurrences of CMV activity. CD4+ T-lymphocyte counts and human immunodeficiency virus (HIV) loads were measured.

RESULTS

All patients had positive initial responses to HAART with an average HIV load decrease of 2.26 log units (range 0.3-5.57). Mean CD4+ T-lymphocyte count at baseline was 45.6 (range 4-107) and increased by an average of 132.5 (range 7-266) within the first 2 to 4 months of HAART. Patients were observed for an average of 15.5 months (range 11-20 months). Six subjects had a vigorous and sustained response to therapy, achieving an average HIV load of 9,400 copies/mL (3.32 log10 decrease) and CD4+ T-lymphocyte count of 158.2 cells/microL. These patients had no CMV retinitis progression. By contrast, two others who attained an average log10 decrease of only 0.48 had modest and short-lived increases in the CD4+ T-lymphocyte count. These patients experienced reactivation of CMV retinitis after 5 and 7 months, respectively.

CONCLUSIONS

Regressed CMV retinitis may remain healed for long periods. However, failure of HAART to induce substantial decreases in HIV load may predict poor or unsustainable rises in the CD4+ T-lymphocyte count and presage recurrence of CMV retinitis. Vigilance in ophthalmic examinations is especially mandatory in these subjects.

Plasma drug levels, genotypic resistance, and virological response to a nelfinavir plus saquinavir-containing regimen

OBJECTIVE

To determine the importance of resistance and drug levels in the response to a dual-protease inhibitor (PI) combination.

METHODS

Prospective study of 62 HIV-positive patients who switched to a salvage regimen including nelfinavir plus saquinavir. Virological response was defined as a decrease in viraemia > 0.5 log10 after 24 weeks. Optimal PI levels were defined as those above the protein binding-corrected 95% inhibitory concentration (IC95), as estimated in the presence of 50% human serum.

RESULTS

Baseline median HIV load was 4.78 log10 copies/ml. The median number of mutations in the protease gene was nine (range, 2-25), predominantly at residues 82 (52%), and 90 (40%). After 24 weeks, 45% of patients had responded and 19% were < 50 copies/ml. A higher number of mutations in the protease gene (12 versus 8;P = 0.001), and the L90M mutation (36% versus 67%; P = 0.001) were associated with treatment failure. Trough levels of nelfinavir and saquinavir were two- and fivefold, respectively, greater than those reached when used as the only PI (2480 and 260 ng/ml, respectively), and they were above the estimated protein-corrected IC95 in 96% and 32% of cases. Thus, the Cmin : IC95 ratio ranged from 0.1 to 10 for nelfinavir and from 0.12 to 3.24 for saquinavir. Suboptimal PI levels were associated with a poorer response, but there was no correlation between optimal drug levels and a better response.

CONCLUSION

Genotypic resistance predicts the virological response to a nelfinavir-saquinavir salvage regimen. Our data suggest that higher than optimal drug levels could be necessary to control the replication of many PI-resistant viruses.

Viral load outcome of non-nucleoside reverse transcriptase inhibitor regimens for 2203 mainly antiretroviral-experienced patients

OBJECTIVE

To assess the factors associated with virologic response to non-nucleoside reverse transcriptase inhibitor (NNRTI)-containing regimens in a large clinic cohort.

DESIGN

Inception cohort.

SETTING

HIV clinics in Europe

PATIENTS

We identified all patients in EuroSIDA who began a regimen including either nevirapine or efavirenz (not both) after July 1997 and for whom pre-therapy viral load and CD4 cell count were known.

MAIN OUTCOME MEASURES

Virological failure.

RESULTS

A total of 1325 patients initiated nevirapine and 878 efavirenz. Respectively, median start dates were October 1998 and May 1999. Other factors at baseline, including CD4 cell count, viral load, previous AIDS, previous antiretroviral drug use and make-up of the NNRTI-containing regimen were all approximately similar between the nevirapine and efavirenz groups. A total of 669 patients experienced virological failure during follow-up. In a Cox model, less protease inhibitors and nucleoside reverse transcriptase inhibitors (NRTIs) previously used, higher CD4 nadir, lower viral load at baseline, a previous AIDS diagnosis and less NRTIs in the regimen were associated with lower risk of virological failure. The relative hazard of virological failure comparing those on efavirenz with those on nevirapine was 0.57 (95% confidence interval, 0.47-0.69; P < 0.0001).

CONCLUSIONS

The difference in virologic outcome between those using nevirapine and efavirenz in this almost entirely drug-experienced population could reflect differences in effectiveness of the drugs in this setting but, despite the similarity between groups at baseline, bias cannot be excluded as an explanation. Replication of these findings in randomized trials and other cohort studies is required.

Response to first protease inhibitor- and efavirenz-containing antiretroviral combination therapy. The Swiss HIV Cohort Study

OBJECTIVE

To compare the response to protease inhibitor (PI) and efavirenz-containing combination therapy among treatment-naive HIV-infected persons.

DESIGN

Prospective observational cohort study.

METHODS

Response to treatment was analysed according to the intent-to-treat principle among antiretroviral-naive patients who started either efavirenz (n = 89) or PI (n = 183) plus two nucleoside reverse transcriptase inhibitors between February 1999 and March 2000 using Kaplan-Meier and multivariable Cox proportional hazard regression methods. Primary endpoint was time to undetectable plasma viral load. Secondary endpoints included the number of CD4 cells gained, virological rebound, treatment change, and clinical progression.

RESULTS

Patients on PI regimens had lower median CD4 counts (165 versus 216 x 5 106/l; P = 0.15) and were more likely to have AIDS at initiation of treatment (25% versus 15% P = 0.048) than patients starting efavirenz regimens. The probability of reaching plasma HIV-1 RNA < 400 copies/ml was higher with efavirenz- than with PI-containing regimens [adjusted hazard ratio, 1.75; 95% confidence interval (CI), 1.34-2.29]. Median times to undetectable viral load were 58 days (95% CI, 44-70 days) for efavirenz-treated and 88 days (95% CI, 79-98 days) for PI-treated patients. The median number of CD4 cells gained in the first 6 months (90 x 10(6) cells/l with efavirenz, 10(7) x 10(6) cells/l with PI; P = 0.63), time to and reasons for treatment change, time to viral rebound, drug intolerance and clinical progression rates were similar in the two treatment groups.

CONCLUSIONS

Treatment with efavirenz-, compared with PI-based regimens, appeared to result in a superior virological response but no difference in immunological or clinical efficacy. The relevance of these observations remains to be determined in studies with longer follow-up.

Comparison of initial combination antiretroviral therapy with a single protease inhibitor, ritonavir and saquinavir, or efavirenz

OBJECTIVE

To compare the effectiveness of initial highly active antiretroviral therapy with either: a single protease inhibitor (PI); ritonavir (RTV)/saquinavir (SQV); or efavirenz (EFV) plus nucleoside reverse transcriptase inhibitors.

DESIGN

Cohort study.

SETTING

Urban HIV clinic.

PATIENTS

Five-hundred and forty-five HIV-1-infected individuals with minimal antiretroviral exposure who started combination therapy with > or = 3 antiretroviral drugs and > or = 1 NRTI to which they had not previously been exposed (single PI, 416; RTV/SQV, 68; EFV, 61).

MAIN OUTCOME MEASURES

HIV-1 RNA < 400 copies/ml within 8 months of starting therapy; time to HIV-1 RNA rebound to > 1000 copies/ml in the subset of patients achieving initial viral suppression; change in CD4 cell count from baseline within 12 months of starting therapy.

RESULTS

By intent-to-treat analysis, initial viral suppression was achieved by 72% of patients in the EFV group, compared to 49% in the single PI group (P = 0.001) and 51% in the RTV/SQV group (P = 0.019). Among patients who achieved initial viral suppression, time to viral rebound was similar in the three groups. Durable viral suppression (> or = 3 consecutive HIV-1 RNA levels < 400 copies/ml for > 6 months) was achieved by 53% of patients in the EFV group, 26% in the single PI group, and 29% in the RTV/SQV group (P < 0.05 for both comparisons with EFV). The median CD4 cell count increase was 139 x 10(6) cells/l, and was similar in the three groups.

CONCLUSIONS

In agreement with a recent clinical trial, use of initial EFV-based combination antiretroviral therapy was associated with higher rates of viral suppression than PI-based therapy in a clinical cohort.

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

Little is known about the long-term clinical outcomes for human immunodeficiency virus (HIV)-infected patients who have received highly active antiretroviral therapy (HAART). Determining factors associated with long-term clinical outcomes early in the course of treatment may allow modifications to be made for patients who are at a greater risk of treatment failure. To evaluate these factors, we studied 213 HIV-infected patients who had received HAART for at least 115 weeks. In the univariate analysis, virological response, which was measured as the change in virus load from baseline at month 3 of treatment, was the single best predictor of clinical outcome (relative hazard, 0.722; P=.001), independent of virological suppression. In the multivariate analysis, virological response and immunologic response, which was measured as an increase in CD4 cell count of >200 cells/mm(3), resulted in better prediction of clinical outcomes than did use of either variable alone (P=.02). Our results indicate that changes in virus load and immunologic response together are good predictors of clinical outcome and can be assessed after the initiation of HAART, which would allow clinicians to identify patients early in the course of therapy who are at greater risk of negative outcome.