Antiviral effect of double and triple drug combinations amongst HIV-infected adults: lessons from the implementation of viral load-driven antiretroviral therapy

Concordance of HIV transmission risk factors elucidated using viral diversification rate and phylogenetic clustering

BACKGROUND AND OBJECTIVES

Although HIV sequence clustering is routinely used to identify subpopulations experiencing elevated transmission, it over-simplifies transmission dynamics and is sensitive to methodology. Complementarily, viral diversification rates can be used to approximate historical transmission rates. Here, we investigated the concordance and sensitivity of HIV transmission risk factors identified by phylogenetic clustering, viral diversification rate, changes in viral diversification rate and a combined approach.

METHODOLOGY

Viral sequences from 9848 people living with HIV in British Columbia, Canada, sampled between 1996 and February 2019, were used to infer phylogenetic trees, from which clusters were identified and viral diversification rates of each tip were calculated. Factors associated with heightened transmission risk were compared across models of cluster membership, viral diversification rate, changes in diversification rate, and viral diversification rate among clusters.

RESULTS

Viruses within larger clusters had higher diversification rates and lower changes in diversification rate than those within smaller clusters; however, rates within individual clusters, independent of size, varied widely. Risk factors for both cluster membership and elevated viral diversification rate included being male, young, a resident of health authority E, previous injection drug use, previous hepatitis C virus infection or a high recent viral load. In a sensitivity analysis, models based on cluster membership had wider confidence intervals and lower concordance of significant effects than viral diversification rate for lower sampling rates.

CONCLUSIONS AND IMPLICATIONS

Viral diversification rate complements phylogenetic clustering, offering a means of evaluating transmission dynamics to guide provision of treatment and prevention services.

LAY SUMMARY

Understanding HIV transmission dynamics within clusters can help prioritize public health resource allocation. We compared socio-demographic and clinical risk factors associated with phylogenetic cluster membership and viral diversification rate, a historical branching rate, in order to assess their relative concordance and sampling sensitivity.

Predictive factors of viral load high-risk events for virological failure in HIV/AIDS patients receiving long-term antiviral therapy

Background

In the era of anti-retroviral therapy (ART), the plasma HIV viral load (VL) is an important primary indicator for monitoring the HIV treatment response. To optimize the clinical management of HIV/AIDS patients, we investigated VL high-risk events related to virological failure (VF) and further explored the preventive factors of VL high-risk events.

Methods

The data were derived from China’s HIV/AIDS Comprehensive Response Information Management System. HIV infected patients who initiated or received ART in Guangxi between 2003 and 2019 were included. The contributions of VL after 6 months of ART to VF and AIDS-related death were analysed by Kaplan-Meier curves, log-rank tests and Cox regression analyses. Both descriptive analyses and bivariate logistic regression were employed to further explore the preventive factors related to VL high-risk events of VF.

Results

The cumulative rates of VF in the high low-level viremia group (high LLV) (χ² = 18.45; P <  0.001) and non-suppressed group (χ² = 82.99; P <  0.001) were significantly higher than those in the viral suppression (VS) group. Therefore, the VL high-risk events of VF was defined as highest VL > 200 copies/ml after 6 months of ART. Compared with the VS group, the adjusted hazard risk was 7.221 (95% CI: 2.668; 19.547) in the high LLV group and 8.351 (95% CI: 4.253; 16.398) in the non-suppressed group. Compared with single patients, married or cohabiting (AOR = 0.591; 95% CI: 0.408, 0.856) and divorced or separated (AOR = 0.425, 95% CI: 0.207, 0.873) patients were negatively associated with VL high-risk events. So were patients acquired HIV homosexually (AOR = 0.572; 95% CI: 0.335, 0.978). However, patients who had ART modification were 1.728 times (95% CI: 1.093, 2.732) more likely to have VL high-risk events, and patients who used cotrimoxazole during ART were 1.843 times (95% CI: 1.271, 2.672) more likely to have VL high-risk events.

Conclusions

A VL greater than 200 copies/ml is a VL high-risk event for VF. Intervention measurements should be adopted to optimize the surveillance of ART in patients who are single or widowed, who have ART modification, and who use cotrimoxazole during ART.

Promoting Undetectable Equals Untransmittable in Sub-Saharan Africa: Implication for Clinical Practice and ART Adherence

In the last decade, reliable scientific evidence has emerged to support the concept that undetectable viral loads prevent human immunodeficiency virus (HIV). Undetectable equals untransmissible (U = U) is a simple message that everyone can understand. The success of this concept depends on strict adherence to antiretroviral therapy (ART) and the attainment of suppressed viral loads (VLs). To achieve U = U in sub-Saharan Africa (SSA), poor adherence to ART, persistent low-level viremia, and the emergence of drug-resistant mutants are challenges that cannot be overlooked. Short of a cure for HIV, U = U can substantially reduce the burden and change the landscape of HIV epidemiology on the continent. From a public health perspective, the U = U concept will reduce stigmatization in persons living with HIV (PLWHIV) in SSA and strengthen public opinion to accept that HIV infection is not a death sentence. This will also promote ART adherence because PLWHIV will aim to achieve U = U within the shortest possible time. This article highlights challenges and barriers to achieving U = U and suggests how to promote the concept to make it beneficial and applicable in SSA. This concept, if expertly packaged by policy-makers, clinicians, health service providers, and HIV control programs, will help to stem the tide of the epidemic in SSA.

Detection of HIV transmission hotspots in British Columbia, Canada: A novel framework for the prioritization and allocation of treatment and prevention resources

Background

Identifying populations at high risk of HIV transmission is critical for prioritizing treatment and prevention resources and achieving the UNAIDS 90-90-90 Targets.

Methods

HIV transmission rates can be estimated from phylogenetic trees as viral lineage-level diversification rates. To identify HIV-1 transmission foci in British Columbia, Canada, we inferred diversification rates from phylogenetic trees of 36 271 HIV-1 sequences from 9630 anonymized individuals. Diversification rates were combined with sociodemographic and clinical data, then aggregated by patients’ area of residence to predict the distribution of new HIV cases between 2008 and 2018. The predictive power of the model was compared with a phylogenetically uninformed model.

Findings

Aggregated diversification rate measures were predictive of new HIV cases in the subsequent year after adjusting for prevalent and incident cases in the previous year. For every one-unit increase in the mean of the top five diversification rates, the number of new HIV cases increased by on average 1·38-fold (95% CI, 1·28–1·49). In a blind prediction of 2018 cases, diversification rate improved the model's specificity by 12%, accuracy by 9%, top 20 agreement by 100%, and correlation of predicted and observed values by 162% relative to a model that incorporated epidemiological data alone.

Interpretation

By predicting the distribution of future HIV cases, a combined phylogenetic and epidemiological approach identifies hotspots where public health resources are needed most.

Funding

Canadian Institutes of Health Research, University of British Columbia, Public Health Agency of Canada, Genome Canada, Genome BC, Michael Smith Foundation for Health Research, and BC Centre for Excellence in HIV/AIDS.

Dispensation of antiretroviral therapy and methadone maintenance therapy at the same facility in a low-barrier setting linked to optimal adherence to HIV treatment

OBJECTIVES

We sought to examine the association between dispensation of methadone maintenance therapy (MMT) and antiretroviral therapy (ART) at the same facility, across multiple low-barrier dispensing outlets, and achieving optimal adherence to ART among people who use illicit drugs (PWUD).

METHODS

We used data from the AIDS Care Cohort to Evaluate Exposure to Survival Services (ACCESS) study, a long-running study of a community-recruited cohort of HIV-positive PWUD, linked to comprehensive HIV clinical records in Vancouver, Canada, a setting of no-cost, universal access to HIV care. The longitudinal relationship between MMT-ART dispensation at the same facility and the odds of ≥ 95% ART adherence was analysed using multivariable generalized linear mixed-effects modelling. We conducted a further analysis using a marginal structural mode with inverse probability of treatment weights as a sensitivity analysis.

RESULTS

This study included data on 1690 interviews of 345 ART- and MMT-exposed participants carried out between June 2012 and December 2017. In the final multivariable model, MMT-ART dispensation, compared with nondispensation at the same facility, was associated with greater odds of achieving ≥ 95% adherence [adjusted odds ratio (AOR) 1.56; 95% confidence interval (CI) 1.26-1.96]. A marginal structural model estimated a 1.48 (95% CI 1.15-1.80) greater odds of ≥ 95% adherence among participants who reported MMT-ART dispensation at the same facility compared with those who did not.

CONCLUSIONS

The odds of achieving optimal adherence to ART were 56% higher during periods in which MMT and ART medications were dispensed at the same facility, in a low-barrier setting. Our findings highlight the need to consider a simpler integrated approach with medication dispensation at the same facility in low-threshold settings.

Combining a Fusion Inhibitory Peptide Targeting the MERS-CoV S2 Protein HR1 Domain and a Neutralizing Antibody Specific for the S1 Protein Receptor-Binding Domain (RBD) Showed Potent Synergism against Pseudotyped MERS-CoV with or without Mutations in RBD

Middle East respiratory syndrome coronavirus (MERS-CoV) has continuously posed a threat to public health worldwide, yet no therapeutics or vaccines are currently available to prevent or treat MERS-CoV infection. We previously identified a fusion inhibitory peptide (HR2P-M2) targeting the MERS-CoV S2 protein HR1 domain and a highly potent neutralizing monoclonal antibody (m336) specific to the S1 spike protein receptor-binding domain (RBD). However, m336 was found to have reduced efficacy against MERS-CoV strains with mutations in RBD, and HR2P-M2 showed low potency, thus limiting the clinical application of each when administered separately. However, we herein report that the combination of m336 and HR2P-M2 exhibited potent synergism in inhibiting MERS-CoV S protein-mediated cell–cell fusion and infection by MERS-CoV pseudoviruses with or without mutations in the RBD, resulting in the enhancement of antiviral activity in contrast to either one administered alone. Thus, this combinatorial strategy could be used in clinics for the urgent treatment of MERS-CoV-infected patients.

Factors associated with low neighborhood cohesion among women living with HIV impacted by social-structural inequities in British Columbia

Built and social environments, including one's perception of their environment, are important determinants of health. The intersection of gender and HIV status may complicate the role of neighborhood cohesion in safety, personal well-being, and health outcomes for populations impacted by social and structural inequities. Among women in particular, social cohesion within the neighborhood they reside in may have a greater influence on health outcomes compared to their male counterparts. We sought to examine perception of neighborhood cohesion (validated scale with a range 0-100, with higher scores indicating higher perceived neighborhood cohesion) among women living with HIV, impacted by social-structural inequities, receiving combination antiretroviral therapy, and enrolled in the Longitudinal Investigations into Supportive Ancillary health services (LISA) study in British Columbia, Canada. Cross-sectional data on neighborhood cohesion and socio-demographic data were collected in an interviewer-administered survey. Of the 1,000 LISA participants interviewed, 908 (including 249 women and 659 men) had complete data for the variables of interest. At the bivariate level, women had worse perceived neighborhood cohesion scores compared to men (median: 56 [95% CI: 44-66] vs. 60 [95% CI: 47-71]). Multivariable model results indicated that for women living with HIV in our sample, greater neighborhood cohesion scores were positively associated with stable housing (β coefficient = 7.85; 95% CI: 3.61, 12.10, p < 0.001), and negatively associated with greater perceived HIV stigma (β coefficient = -1.19; 95% CI: -2.24 to-0.15; p = 0.025). The results illustrate the gendered nature of experiencing built and social environments, and highlight the need for women-centred interventions to address the social determinants of HIV burden associated with negative perceptions of neighborhood cohesion.

Enhancement of the antiviral activity against caprine herpesvirus type 1 of Acyclovir in association with Mizoribine

Caprine herpesvirus 1 (CpHV-1) infection in goats is responsible for genital lesions resembling the lesions induced by herpesvirus 2 in humans (HHV-2). The immunosuppressive drug Mizoribine (MIZ) is able to increase the antiviral activity of Acyclovir (ACV) against herpesvirus infections, raising interesting perspectives on new combined therapeutic strategies. In this study the anti-CpHV-1 activity in vitro of ACV alone or in combination with MIZ was evaluated. ACV (100μg/ml) displayed an antiviral effect on CpHV-1 replication. This inhibitory effect was higher when ACV (100μg/ml) was used in association with MIZ (20μg/ml). Other combinations of ACV and MIZ in various concentrations were not as effective as ACV 100μg/ml/MIZ 20μg/ml. These findings suggest that the association of ACV and MIZ is potentially useful for treatment of genital infection by herpesviruses.

Initial Therapy for Human Immunodeficiency Virus: Broadening the Options

The goal of investigation into new therapeutic options for HIV/AIDS is to further the achievements of highly active antiretroviral therapy by developing new drugs with improved efficacy. Although several therapies are currently available for initial therapy in HIV-infected patients, ongoing research focuses on additions to existing and novel drug classes that might have improved pharmacokinetic and tolerability profiles, as well as on new therapeutic combinations that might result in synergistic activity. To retain activity against resistant strains, novel drugs need to target the numerous critical points in the life cycle of HIV, inhibiting different enzyme subsites than those affected by antiretroviral agents currently in use. An improvement in patient adherence to therapy is another key objective of efforts in HIV treatment, as suboptimal drug levels are a main determinant of antiretroviral regimen failure. This article reviews the current classes of antiretroviral agents in development, describing the clinical data obtained to date. These agents may have potential use as initial therapy in HIV patients.

Cohort Profile: HAART Observational Medical Evaluation and Research (HOMER) cohort

Since 1986, antiretroviral therapy (ART) has been available free of charge to individuals living with HIV in British Columbia (BC), Canada, through the BC Centre of Excellence in HIV/AIDS (BC-CfE) Drug Treatment Program (DTP). The Highly Active Antiretroviral Therapy (HAART) Observational Medical Evaluation and Research (HOMER) cohort was established in 1996 to maintain a prospective record of clinical measurements and medication profiles of a subset of DTP participants initiating HAART in BC. This unique cohort provides a comprehensive data source to investigate mortality, prognostic factors and treatment response among people living with HIV in BC from the inception of HAART. Currently over 5000 individuals are enrolled in the HOMER cohort. Data captured include socio-demographic characteristics (e.g. sex, age, ethnicity, health authority), clinical variables (e.g. CD4 cell count, plasma HIV viral load, AIDS-defining illness, hepatitis C co-infection, mortality) and treatment variables (e.g. HAART regimens, date of treatment initiation, treatment interruptions, adherence data, resistance testing). Research findings from the HOMER cohort have featured in numerous high-impact peer-reviewed journals. The HOMER cohort collaborates with other HIV cohorts on both national and international scales to answer complex HIV-specific research questions, and welcomes input from external investigators regarding potential research proposals or future collaborations. For further information please contact the principal investigator, Dr Robert Hogg (robert_hogg@sfu.ca).

Middle East respiratory syndrome coronavirus (MERS-CoV) entry inhibitors targeting spike protein

The recent outbreak of Middle East respiratory syndrome (MERS) coronavirus (MERS-CoV) infection has led to more than 800 laboratory-confirmed MERS cases with a high case fatality rate (∼35%), posing a serious threat to global public health and calling for the development of effective and safe therapeutic and prophylactic strategies to treat and prevent MERS-CoV infection. Here we discuss the most recent studies on the structure of the MERS-CoV spike protein and its role in virus binding and entry, and the development of MERS-CoV entry/fusion inhibitors targeting the S1 subunit, particularly the receptor-binding domain (RBD), and the S2 subunit, especially the HR1 region, of the MERS-CoV spike protein. We then look ahead to future applications of these viral entry/fusion inhibitors, either alone or in combination with specific and nonspecific MERS-CoV replication inhibitors, for the treatment and prevention of MERS-CoV infection.

Effectiveness of option B highly active antiretroviral therapy (HAART) prevention of mother-to-child transmission (PMTCT) in pregnant HIV women

BACKGROUND

Ensuring that no baby is born with HIV is an essential step towards achieving an AIDS-free generation. To achieve this, strategies that decouple links between childbirth and HIV transmission are necessary. Traditional forms of prevention of mother-to-child transmission of HIV (PMTCT), has been recommended. Recognizing the importance and challenges of combination of methods to achieve rapid PMTCT, the World Health Organization (WHO) recommended option B Highly Active Antiretroviral Therapy (HAART) for all HIV-positive pregnant women. This study aimed to evaluate the effectiveness of the HAART in PMTCT. A cohort of HIV-infected pregnant women in Kenya were obtained from the DREAM Center, Nairobi. The study participants underwent adherence counselling and Option B of HAART [Nevirapine(NVP) + Lamivudine + Zidovudine] at the fourth week of gestation followed by an intravenous NVP administration intrapartum and postpartum NVP syrup to the respective infants for six weeks. Absolute pre-HAART and post-HAART CD4 counts and viral loads counts were determined. Comparison of the CD4 counts and viral loads before and after administration of HAART were done using Wilcoxon's Matched Pairs Signed-Ranks Test.

FINDINGS

The mean absolute CD4 cell counts in mothers after administration of HAART was significantly higher (Z = 15.664, p < 0.001) than before the administration of HAART). Also the viral load of the mothers significantly (Z = 11.324, p < 0.001) reduced following HAART treatment. Following the HAART administration in mothers, up to 90% of children were confirmed to be HIV negative.

CONCLUSION

Administration of HAART to mothers and children demonstrated an effective mechanism of PMTCT. However, other aspects of HAART such as adherence, costs, mothers behaviour during HAART, and the child feeding programme during the therapy should further be evaluated and ascertained how they can affect the overall efficacy of option B HAART in PMTCT.

CD4, viral load response, and adherence among antiretroviral-naive breast-feeding women receiving triple antiretroviral prophylaxis for prevention of mother-to-child transmission of HIV in Kisumu, Kenya

BACKGROUND

Health benefits and survival of an exclusively breast-fed infant is dependent on the mother's health; thus, the need for antiretroviral (ARV) intervention for prevention of mother-to-child transmission (PMTCT). Achieving maternal health benefits from these regimens requires adherence to the treatments and close monitoring. We evaluated virologic, immunologic responses, and adherence among women receiving maternal triple ARV prophylaxis consisting of lamivudine/zidovudine and nevirapine or nelfinavir in the Kisumu Breastfeeding Study.

METHODS

We analyzed baseline demographic data, trends in CD4 count, and viral load (VL) at enrollment (32-34 weeks gestation), delivery, 14 and 24 weeks postpartum among 434 women who remained in the study at 24 weeks postpartum. Adherence rates were determined using pill counts reinforced by self-report and drug calendar. We dichotomized adherence as ≥95% versus <95%.

RESULTS

Among the 434 women, 84% (n = 366) had adherence ≥95%. The proportion of women with undetectable VL (<400 copies/mL) increased from 6% at baseline to 79%, and that of those with CD4 count <250 cells per microliter decreased from 23% (100) at baseline to 5% (22) at 24 weeks postpartum. In discrete-survival model, time to achieving VL suppression was associated with baseline VL <5.0 log copies per milliliter, parity ≥2, and use of nelfinavir- versus nevirapine-based ARV. Association between undetectable VL with duration of therapy (P < 0.0001) and adherence with suppression of VL (P = 0.001) was observed.

CONCLUSIONS

High baseline VL and short exposure to ARVs for PMTCT are risk factors for failing to achieve undetectable VL. These findings support the new WHO guidelines for early initiation of ARV prophylaxis for PMTCT for maximal reduction of maternal VL.

Antiretroviral therapy initiated soon after HIV diagnosis as standard care: potential to save lives?

In 2008, an estimated 33.4 million people were infected with human immunodeficiency virus (HIV) and ~4 million people were receiving antiretroviral therapy (ART). However, in 2007, an estimated 6.7 million people were in need of ART under the current World Health Organization guidelines, and 2.7 million more people became infected with HIV. Most of those not currently eligible for ART will become eligible within the next decade, making the current treatment strategy unsustainable. The development of cheaper, less toxic, and more potent antiretrovirals over the past decade has made it possible to consider novel strategies of arresting the HIV/AIDS epidemic. Evidence is growing that ART can be used to prevent HIV transmission and that earlier initiation of treatment is beneficial for those infected with HIV. A mathematical model predicts that by testing whole communities annually and treating all who are infected immediately, up to 7.2 million AIDS-related deaths could be prevented in the next 40 years, long-term funding required to fight the HIV epidemic could be reduced, and, most importantly, control of the HIV/ AIDS epidemic could be regained within 1–2 years of full-scale implementation of the strategy. We discuss the development of the concept of ART for the prevention of HIV transmission and the modeled impact that a test-and-treat strategy could have on the HIV epidemic, and consequently argue that a field trial should be carried out to confirm model parameters, highlight any practical problems, and test the model’s predictions.

Prevalence of bone mineral density abnormalities and related risk factors in an ambulatory HIV clinic population

Bone mineral density (BMD) abnormalities are observed frequently among human immunodeficiency virus (HIV)-infected patients. Risk factors for reduced BMD in the setting of HIV have been previously studied, but detailed antiretroviral treatment history is often not available. A cross-sectional observational study was conducted between 2005 and 2007 among unselected HIV-infected adults attending an ambulatory urban HIV clinic. Dual-energy X-ray absorptiometry (DXA) scans of lumbar spine and femoral neck, full laboratory profile, detailed questionnaire, and antiretroviral history were obtained. Univariate and multivariate logistic regression analyses were performed to investigate factors associated with BMD below the expected range for age. Two hundred ninety patients completed the study: 80% Caucasians, 89% males, with median age of 49 yr. Low BMD as assessed by Z-score was present in 19.7% of the patients. By multivariate analysis, only lower body mass index (BMI) was an independent risk factor for low BMD. Cumulative exposure to protease inhibitors, non-nucleosides, and individual nucleoside and nucleotide analogs were not independently associated with low BMD. In conclusion, a 19.7% prevalence of abnormal BMD by DXA scan was identified in an unselected group of HIV-infected adults. Lower BMI was independently associated with low BMD. No correlation was found between abnormal BMD and cumulative exposure to any antiretroviral agents.

Expanding access to HAART: a cost-effective approach for treating and preventing HIV

OBJECTIVE

HIV continues to present a substantial global health burden. Given the high direct medical costs associated with the disease, prevention of new transmission is an important element in limiting economic burden. In addition to providing therapeutic benefit, treatment with HAART has potential to prevent transmission of HIV. The objective in this study was to perform an economic evaluation of the incremental net benefit associated with an intervention to expand treatment with HAART in British Columbia, Canada.

DESIGN

A mathematical model describing transmission of HIV, integrated with a microsimulation model describing the clinical and economic course of HIV.

METHODS

The primary outcome was the incremental net benefit of expanding treatment with HAART from 50 to 75% of clinically eligible individuals in British Columbia, assuming a willingness-to-pay threshold of US$ 50,000 per quality-adjusted life year. Direct medical costs included were antiretroviral and nonantiretroviral medications, hospitalizations, physician visits, and laboratory tests. The mathematical and microsimulation models were based on patient characteristics observed in British Columbia. Longitudinal data described health services utilization, clinical progression, and survival for all individuals receiving treatment for HIV in British Columbia.

RESULTS

Over 30 years, the HAART expansion scenario was associated with a net benefit of US$ 900 million (95% confidence interval US$ 493 million to 1.45 billion).

CONCLUSION

Increasing the HAART treatment rate from 50 to 75% of clinically eligible individuals in British Columbia appears to be a cost-effective strategy based on this model. These cost-effectiveness results are consistent with public health objectives: all individuals who are eligible for an established life-saving treatment should receive it.

A sex-role-preference model for HIV transmission among men who have sex with men in China

Background

Men who have sex with men (MSM) are much more likely to be infected with HIV than the general population. China has a sizable population of MSM, including gay, bisexual men, money boys and some rural workers. So reducing HIV infection in this population is an important component of the national HIV/AIDS prevention and control program.

Methods

We develop a mathematical model using a sex-role-preference framework to predict HIV infection in the MSM population and to evaluate different intervention strategies.

Results

An analytic formula for the basic reproduction ratio R₀ was obtained; this yields R₀ = 3.9296 in the current situation, so HIV will spread very fast in the MSM population if no intervention measure is implemented in a timely fashion. The persistence of HIV infection and the existence of disease equilibrium (or equilibria) are also shown. We utilized our model to simulate possible outcomes of antiretroviral therapy and vaccination for the MSM population. We compared the effects of these intervention measures under different assumptions about MSM behaviour. We also found that R₀ is a decreasing function of the death rate of HIV-infected individuals, following a power law at least asymptotically.

Conclusion

HIV will spread very fast in the MSM population unless intervention measures are implemented urgently. Antiretroviral therapy can have substantial impact on the reduction of HIV among the MSM population, even if disinhibition is considered. The effect of protected sexual behaviour on controlling the epidemic in the MSM population largely depends on the sex-ratio preference of different sub-populations.

In vitro synergistic activity against CCR5-tropic HIV-1 with combinations of potential candidate microbicide molecules HHA, KRV2110 and enfuvirtide (T20)

OBJECTIVES

To block the different mechanisms of HIV mucosal transmission, it is likely that use of several microbicide molecules will lead to the best protection against HIV transmission. Indeed, the combination of microbicides with complementary mechanisms of action is expected to increase the antiviral potency of the formulation.

METHODS

The gp120-interacting plant lectin HHA ('Hippeastrum hybrid agglutinin'), the non-nucleoside reverse transcriptase inhibitor KRV2110 and the fusion inhibitor enfuvirtide (T20) were combined in 12 drug associations by using the Ray combination design method. Their activity against HIV-1(BaL) was assessed by the lymphocyte infectivity reduction assay and by the single-cycle BaL pseudovirus (PV) assay. In addition, their cell tolerance was evaluated for HEC-1 and HeLa epithelial cell lines, both originating from genital tissue.

RESULTS

All evaluated combinations showed synergistic activity in both lymphocyte infectivity reduction and single-cycle BaL PV assays. The combination HHA + KRV2110 resulted in the highest cell viability, whereas the combinations including T20 exhibited a dose-dependent decrease in cell viability, demonstrating the differential tolerance of epithelial cell lines to the combinations.

CONCLUSIONS

These observations provide a rational basis for in vitro testing of microbicide candidate molecule combinations, including anti-HIV-1 and cytotoxic cellular assays.

Expanded access to highly active antiretroviral therapy: a potentially powerful strategy to curb the growth of the HIV epidemic

We developed a mathematical model using a multiple source of infection framework to assess the potential effect of the expansion of highly active antiretroviral therapy (HAART) coverage among those in medical need on the number of individuals testing newly positive for human immunodeficiency virus (HIV) and on related costs in British Columbia, Canada, over the next 25 years. The model was calibrated using retrospective data describing antiretroviral therapy utilization and individuals testing newly positive for HIV in the province. Different scenarios were investigated on the basis of varying assumptions regarding drug resistance, adherence to HAART, therapeutic guidelines, degree of HAART coverage, and the timing of HAART uptake. Expansion of HAART lead to substantial reductions in the growth of the HIV epidemic and related costs. These results provide powerful additional motivation to accelerate the roll out of HAART programs aggressively targeting those in medical need, both for their own benefit and as a means of decreasing new HIV infections.

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.

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.

Continued improvement in survival among HIV-infected individuals with newer forms of highly active antiretroviral therapy

OBJECTIVE

To characterize the temporal changes in mortality and life expectancy among HIV-positive individuals initiating antiretroviral therapy in British Columbia, Canada, from 1993 to 2004.

METHODS

This analysis was restricted to 2238 antiretroviral-naive HIV-positive individuals who started antiretroviral therapy between January 1993 and September 2004. The primary analysis endpoint was all-cause mortality stratified by four time periods: 1993-1995, 1996-1998, 1999-2001, and 2002-2004. Cox proportional hazard models, with associated 95% confidence intervals (CI), were used to estimate the hazard of death. Abridged life tables were constructed to compare life expectancies at the age of 20 years.

RESULTS

Product limit estimates of the cumulative mortality rate at 12 months after therapy initiation decreased from 15.8% (+/- 1.6%) in 1993-1995 to 6.1% (+/- 1.1%) in 2002-2004. Life expectancy at the age of 20 years has increased from 9.1 years (+/- 2.3 years) in 1993-1995 to 23.6 years (+/- 4.4 years) in 2002-2004. Subjects in 1993-1995 were more likely to die than those who started therapy in 2002-2004 (hazard ratio 2.78; 95% CI 1.92-3.85). Patients who initiated dual therapy or therapies containing three or more antiretroviral drugs were, respectively, 1.49 (95% CI 1.23-1.82) and 2.56 (95% CI 2.13-3.13) times less likely to die than those who started on monotherapy.

CONCLUSION

A significant and progressive decrease in mortality and increase in life expectancy were observed over the 12-year study period. The increase in life expectancy and decrease in mortality were directly associated with the use of modern forms of HAART.

Antiretroviral therapy in the treatment of HIV-associated nephropathy

BACKGROUND

The effect of antiretroviral therapy (ART) on the clinical course of patients with human immunodeficiency virus (HIV)-associated nephropathy (HIVAN) is not well-established. This study was undertaken to further elucidate the potential benefit of ART in HIV-infected patients with documented HIVAN.

METHODS

A cohort of 263 consecutive HIV-infected patients referred to the Johns Hopkins renal clinic from 1995 to 2004 was examined. Patients were included if they had biopsy-proven HIVAN and did not require dialysis within 1 month of their kidney biopsy. The cumulative probability of renal survival was calculated using the Kaplan-Meier method. Multivariate analysis was performed using the Cox regression method.

RESULTS

Fifty-three patients among 152 biopsied patients had HIVAN. Among 36 patients who met the inclusion criteria, 26 were treated with ART (group I) and 10 patients were not (group II). Except for age, baseline demographics and clinical characteristics were similar in the two groups. Renal survival was significantly better in the group receiving ART by both univariate (P = 0.025) and multivariate analysis (overall adjusted hazard ratio = 0.30; 95% confidence interval 0.09-0.98; P < 0.05) for ART compared with no treatment.

CONCLUSIONS

Patients with biopsy-proven HIVAN treated with ART had better renal survival compared with patients who did not receive ART. HIVAN should be considered as an indication to initiate ART.

Impact of HAART and injection drug use on life expectancy of two HIV-positive cohorts in British Columbia

BACKGROUND

The introduction of HAART has led to consistent improvements in survival among HIV-infected individuals. However, there is evidence that not all populations have benefited equally from HAART and that mortality rates are higher in HIV-infected injection drug users than in non-users.

OBJECTIVE

To model life expectancies for HIV-positive individuals subdivided according to history of injection drug use and treatment with HAART.

DESIGN

Population-based study of HIV-positive persons in British Columbia's HIV/AIDS treatment program.

METHODS

The primary outcome measures in this study were life expectancy at exact age 20 and potential years of life lost.

RESULTS

The highest life expectancy (38.9 years) and lowest potential years of life lost were measured for individuals taking HAART and without a history of injection drug use. The lowest life expectancy (19.1 years) and highest potential years of life lost were measured in HIV-positive injection drug users who were not taking HAART.

CONCLUSIONS

There are substantial disparities in life expectancy for persons living with HIV in British Columbia. Members of the injection drug community, particularly those who are not taking HAART, experience elevated mortality in comparison with those without a history of drug use.

Effect of sociodemographic, clinical-prophylactic and therapeutic procedures on survival of AIDS patients assisted in a Brazilian outpatient clinic

The Brazilian AIDS Program offers free and universal access to antiretroviral therapy. This study investigates the influence of sociodemographic, clinical-prophylactic and therapeutic factors on survival, after AIDS diagnosis, in an open cohort of 1,420 patients assisted in a university hospital in the city of Rio de Janeiro (1995 _ 2002). Kaplan-Meier and Cox proportional hazards models were used to estimate the effect of variables in the three dimensions studied. The overall survival time of the upper quartile was 24 months (CI95%= 20.5-27.5), increasing from 14 months, in 1995, to 46 months, in 1998. We found a protective effect of heterosexual behavior against death that could be attributed to the increasing female-to-male sex ratio in the cohort, which coincided with the time of therapy introduction. Low schooling, hospital admission and lack of follow-up were identified as risk factors for death; PCP and Toxoplasmosis prophylaxis were protective. The number of attempts required to consolidate the antiretroviral therapy showed no significant effect on survival. The full model, which includes the number of antiretroviral drugs in the regimen, confirmed the triple therapy as the best regimen. This study brings important information for designing guidelines to deal with different aspects related to the practical management of patients and their behavior, thus contributing to the success of the program of free access to antiretroviral therapy implemented in Brazil.

Combination of candidate microbicides cellulose acetate 1,2-benzenedicarboxylate and UC781 has synergistic and complementary effects against human immunodeficiency virus type 1 infection

The combination of two candidate microbicides, cellulose acetate 1,2-benzenedicarboxylate (CAP), a polymer that blocks human immunodeficiency virus type 1 (HIV-1) entry by targeting gp120 and gp41, and UC781, a tight-binding HIV-1 reverse transcriptase inhibitor (RTI), resulted in effective synergy for inhibition of MT-2 cell infection by HIV-1(IIIB), a laboratory-adapted virus strain. The 95% effective concentration values for the combination were reduced about 15- to 20-fold compared with those corresponding to the single compounds. The combination of CAP and UC781 is also synergistic in inhibiting infection of peripheral blood mononuclear cells by a primary HIV-1 isolate, 92US657. Combinations of CAP with other RTIs, such as efavirenz or zidovudine, also had significant synergistic effects on the inhibition of HIV-1 infection. In addition, CAP and UC781 had complementary effects against HIV-1 infection since (i) CAP inhibited infection by the UC781-resistant strain HIV-1(IIIB) A17 and (ii) pretreatment of MT-2 cells with UC781, but not CAP, abolished subsequent infection after removal of the compound. This suggests that the combination of CAP and UC781 represents a promising candidate microbicide for prevention of sexual transmission of HIV-1.

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.

Fungal Phenalenones Inhibit HIV-1 Integrase

A phenalenone compound, atrovenetinone methyl acetal, was isolated from a culture broth of Penicillium sp. FKI-1463 as an HIV-1 integrase inhibitor, and it showed anti-HIV activity in vitro. HIV-1 integrase inhibition and anti-HIV activity of two other natural phenalenones were also studied. Among the tested compounds, funalenone inhibited HIV-1 integrase with an IC50 value of 10 microM and showed the best selectivity (anti-HIV, IC50=1.7 microM; cytotoxicity, IC50=87 microM).

Outpatient pharmacy care and HIV viral load response among patients on HAART

Adherence to highly active antiretroviral therapy (HAART) is necessary to achieve long-term effectiveness. The impact of HIV/AIDS-specific pharmacy services on patient adherence and HIV viral suppression is currently not well described. This study aimed to compare the impact of differing levels of HIV-pharmacy care on adherence and time to HIV viral suppression among participants on HAART enrolled in a population-based HIV/AIDS drug treatment programme in British Columbia. We performed a retrospective observational study of 788 treatment-naïve patients who started HAART between August 1997 and July 2000 and were followed until 31 March 2002. The degree of outpatient pharmacy care was defined according to pharmacy dispensing site for the participants' first prescription of HAART: highest at the AIDS-tertiary care hospital outpatient pharmacies, intermediate at HIV/AIDS drug treatment programme funded off-site pharmacies and lowest at family physician's offices. Cox-proportional hazard models examined the independent effect of pharmacy dispensing site on time to two consecutive HIV viral suppressions controlling for other prognostic factors including physicians' experience, age, gender, injection drug use, use of therapy containing NNRTI versus PI, adherence >90%, AIDS diagnosis at baseline, baseline CD4 cell count and HIV viral load. The median time on antiretrovirals was 28 months (IQR=14-38). There were 489 (62.1%) participants who obtained their medications from the AIDS-tertiary care outpatient pharmacies; 98 (12.4%) from off-site pharmacies and 201 (25.5%) from their physicians' offices. The proportion of patients exhibiting >90% adherence to treatment was observed to be higher among patients receiving their HAART at the AIDS-tertiary care pharmacies compared to off-site pharmacies and to physicians' offices (70.4, 59.2 and 55.7%, respectively; p=0.0001). After adjusting for other prognostic factors, subjects who were first dispensed medications from the AIDS-tertiary care pharmacy were 1.42 times (CI: 1.10-1.84) more likely to achieve HIV viral suppression than those getting their medications from off-site pharmacies and physicians' offices. Providing regular outpatient pharmacy care is independently associated with improved HIV viral load response through enhanced adherence to HAART. Standardization of pharmacy practices for dispensing HAART may improve outcomes for patients who receive their HIV medications from other non-tertiary care pharmacy sites.

Knowledge of HIV Postexposure Prophylaxis in a Population of HIV-Positive Outpatients: Results of a French National Survey

Since 1998, French HIV guidelines have recommended use of HIV prophylaxis after unprotected sex (postexposure prophylaxis, or PEP) with an HIV-positive partner. To characterize factors associated with lack of PEP knowledge in an HIV-positive population, a cross-sectional survey was conducted of 737 French HIV-positive outpatients followed in AIDS care units of 2 regions accounting for 60% of French AIDS cases. Information was collected through face-to-face interviews. The sample was weighted to improve national validity. Median age was 41 years, 73.2% of patients were male, and 8.5% reported HIV-related risk behaviors. Those who knew about PEP and those who did not were compared with chi2 tests and logistic regression. One third of the sample had never heard of PEP. In multivariate analysis, lack of PEP knowledge was associated with older age, low educational level, unstable housing, unawareness of current HIV laboratory data, and lack of ability to confide in nurse and to seek out information from various sources. The increased number of people living with HIV infection as a chronic disease raises new challenges for its secondary prevention. Preventive programs aimed at HIV-positive individuals and their sexual partners are strongly needed.

Adherence is not a barrier to successful antiretroviral therapy in South Africa

OBJECTIVE

To determine adherence of an indigent African HIV-infected cohort initiating antiretroviral therapy (ART); to identify predictors of incomplete adherence (< 95%) and virologic failure (> 400 HIV RNA copies/ml).

DESIGN

Prospective monitoring of adherence in a poor HIV-positive cohort, attending a public sector hospital and receiving ART through phase III studies.

METHODS

Adherence to ART was determined over 48 weeks by counting tablet-returns. Logistic regression models including age, WHO HIV stage, home language, socio-economic status, complexity and type of regimen were fitted to determine predictors of incomplete adherence and virologic failure at 48 weeks.

RESULTS

289 patients were recruited between January 1996 and May 2001. Median (mean) adherence of the cohort was 93.5% (87.2%). Three times daily dosing [risk ratio (RR), 3.07; 95% confidence interval (CI), 1.40-6.74], speaking English (RR, 0.41; 95% CI, 0.21-0.80) and age (RR, 0.97; 95% CI, 0.94-0.99) were independent predictors of incomplete adherence. Socio-economic status, sex and HIV stage did not predict adherence. Independent predictors of virologic failure included baseline viral load (RR, 2.57; 95% CI, 1.57-4.22) and three times daily dosing (RR, 2.64; 95% CI, 1.23-5.66), incomplete adherence (RR, 1.92; 95% CI, 1.10-3.57), age (RR, 0.96; 95% CI, 0.92-0.99) and dual nucleoside therapy (RR, 2.69; 95% CI, 1.17-6.15).

CONCLUSION

The proportion of individuals achieving viral suppression matched results from the developing world. Speaking the same language as site staff and simplified dosing frequency were beneficial. Socio-economic status had no impact on adherence and should not be used as a limitation to ART access.

Socioeconomic status, access to triple therapy, and survival from HIV-disease since 1996

BACKGROUND

In the era before highly active antiretroviral therapy (HAART), socioeconomic status was associated with survival from HIV disease. We have explored socioeconomic status, access to triple therapy (HAART), and mortality in the context of a universal healthcare system.

METHODS

We evaluated 1408 individuals who initiated double or triple therapy between 1 August 1996 and 31 December 1999, and were followed until 31 March 2000. Cumulative HIV-related mortality rates were estimated using Kaplan-Meier methods and Cox proportional hazards regression.

RESULTS

In the overall Cox model, we found that adherence [risk ratio (RR) 0.83; per 10% increase], CD4 cell count (RR 1.53; per 100 cell decrease), and lower socioeconomic status (RR 2.19; high versus low), were associated with HIV-related mortality. However, socioeconomic status was not significant among patients prescribed triple therapy in a stratified analysis, or in a sub-analysis restricted to patients prescribed HAART in the initial regimen. When we investigated if inequitable access to HAART by socio-economic status could explain the discrepancy, we found that persons in the lower socio-economic strata were less likely to be prescribed triple therapy even after adjustment for clinical characteristics.

CONCLUSION

In a universal healthcare system, socioeconomic status was strongly associated with HIV-related mortality. When we investigated possible explanations for this association, we found that individuals of lower socioeconomic status were less likely to receive triple therapy after adjustment for clinical characteristics. Our findings highlight the need for the monitoring of therapeutic guidelines to ensure equitable access, as treatment strategies are updated.

Combination of Protease Inhibitors for the Treatment of HIV-1-Infected Patients: A Review of Pharmacokinetics and Clinical Experience

The use of highly active antiretroviral therapy, the combination of at least three different antiretroviral drugs for the treatment of HIV-1 infection, has greatly improved the prognosis for HIV-1-infected patients. The efficacy of a combination of a protease inhibitor (PI) plus two nucleoside analogue reverse transcriptase inhibitors has been well established over a period of up to 3 years. However, virological treatment failure has been reported in 40–60% of unselected patients within 1 year after initiation of a PI-containing regimen. This observation may, at least in part, be attributed to the poor pharmacokinetic characteristics of the PIs. Given as a single agent the PIs have several pharmacokinetic limitations; relatively short plasma-elimination half-lives and a modest and variable oral bioavailability, which is, for some of the PIs, influenced by food. To overcome these suboptimal pharmacokinetics, high doses (requiring large numbers of pills) must be ingested, often with food restrictions, which complicates patient adherence to the prescribed regimen.

Positive drug–drug interactions increase the exposure to the PIs, allowing administration of lower doses at reduced dosing frequencies with less dietary restrictions. In addition to increasing the potency of an antiretroviral regimen, combinations of PIs may enhance patient adherence, both of which will contribute to a more durable suppression of viral replication. The favourable pharmacokinetics of PIs in combination are a result of interactions through cytochrome P450 3A4 (CYP3A4) isoenzymes and, possibly, the multi-drug transporting P-glycoprotein (P-gp). Antiretroviral synergy between PIs and non-overlapping primary resistance patterns in the HIV-1 protease genome may further enhance the anti-retroviral potency and durability of combinations of PIs. Many combinations contain ritonavir because this PI has the most pronounced inhibiting effects on CYP3A4. The combination of saquinavir and ritonavir, both in a dose of 400 mg twice-a-day, is the most studied double PI combination, with clinical experience extending over 3 years. Combination of a PI with a low dose of ritonavir (≤400 mg/day), only to boost its pharmacokinetic properties, seems an attractive option for patients who cannot tolerate higher doses of ritonavir. A recently introduced PI, lopinavir, has been co-formulated with low-dose ritonavir, which allows for a convenient three-capsules, twice-a-day dosing regimen. In an attempt to prolong suppression of viral replication combinations of PIs are becoming increasingly popular. However, further clinical studies are needed to identify the optimal combinations for treatment of antiretroviral naive and experienced HIV-1-infected patients. This review covers combinations of saquinavir, indinavir, nelfinavir, amprenavir and lopinavir with different doses of ritonavir, as well as the combinations of saquinavir and indinavir with nelfinavir.

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.

Carrier rate of zidovudine-resistant HIV-1: the impact of failing therapy on transmission of resistant strains

OBJECTIVE

Because maintenance of treatment success in HIV-1 infection requires viruses to remain therapy sensitive in drug-naive seropositive persons, we looked at the primary infections caused by drug-resistant HIV-1 over time. Furthermore, to study the coverage rate of therapy and therapy failure in relation to the transmission of resistant viruses a mathematical model was developed.

DESIGN

The reverse transcriptase and protease genes of viruses were analysed in newly infected people in the period 1990-1998 in the Amsterdam Cohort Study on HIV infection and AIDS in homosexual men.

METHODS

The mathematical model was based on the coverage of drug regimens selecting zidovudine (ZDV) resistance, the lag time in which resistance is gained or lost, the death rate of people infected with resistant virus, and the replacement of resistance-selecting regimens by more potent treatments that substantially reduce viral load and mortality.

RESULTS

Of 43 individuals with a primary HIV-infection, three (7%) harboured ZDV-resistant viruses. The first of the ZDV-resistant strains was transmitted in 1995, the last two in 1996. The build-up of ZDV resistance was described by the mathematical model indicating that the equilibrium level of resistance due to treatment depends only on the treatment rate and the outflow rate of patients with resistance virus.

CONCLUSIONS

Our model indicates that the frequency of viral resistance in a population is determined largely by the number of individuals on insufficient or failing therapy and is influenced only modestly by secondary transmission of ZDV-resistant strains.

Prognostic factors of combined viral load and CD4+ cell count responses under triple antiretroviral therapy, Aquitaine cohort, 1996-1998

OBJECTIVE

To describe the viroimmunologic response and its prognostic factors 6 months after initiating triple antiretroviral therapy in a cohort of HIV-1-infected patients.

METHODS

Positive virologic response during follow-up (VL+) was defined as plasma HIV RNA level <500 copies/ml and positive immunologic response (CD4+) as an increase of CD4+ count of at least 50 cells/mm3. Four categories of response were defined: VL+/CD4+; VL+/CD4-; VL-/CD4+ and VL-/CD4-. Prognostic factors were studied through a polytomous logistic regression (VL-/CD4-, as reference).

RESULTS

Baseline characteristics of the 478 studied patients were: 22% at AIDS stage, 77% pretreated, median CD4+ cell count 195/mm3 and HIV RNA level 4.42 log. At 6 months 37.5% were VL+/CD4+; 15.7% VL+/CD4-; 23.8% VL-/CD4+ and 23.0% VL-/CD4-. Baseline HIV RNA level was associated to a higher risk of VL-/CD4+ response. More advanced age was associated with a higher risk of isolated immunologic failure (VL+/CD4-), whereas pretreatment and saquinavir therapy were associated with a lower frequency of positive virologic response independently of immunologic response.

CONCLUSION

HIV-RNA level, pretreatment, and saquinavir therapy were already known to be linked to therapeutic response. Based on our results, a high baseline HIV-RNA level is associated with isolated immunologic response; moreover, age should be of importance in treatment decision.

Statistical advances in AIDS therapy trials

This paper reviews recent statistical advances in HIV/AIDS therapy trials. Our emphasis is on three emerging areas that address key challenges in AIDS research: the determination of optimal treatment sequences, estimating efficacy of intended treatment, and inference for repeated measures with dependent censoring. A common theme of these topics is the use of observational data within clinical trials to answer questions not addressed by the conventional intent-to-treat analysis. We also give a brief overview of some recent contributions to other topics relevant to AIDS clinical trials, including modelling of treatment compliance data, modelling of repeated measures, and group sequential testing.

Actinohivin, a novel anti-HIV protein from an actinomycete that inhibits syncytium formation: isolation, characterization, and biological activities

Blocking human immunodeficiency virus (HIV) entry into target cells is an important goal of HIV and acquired immune deficiency syndrome (AIDS) therapies. We have searched for anti-HIV substances from microorganisms using a syncytium formation assay system constructed with HeLa/CD4/Lac-Z and HeLa/T-env/Tat cells. We discovered a novel anti-HIV protein that inhibits syncytium formation, designated as actinohivin, from a cultured broth of a soil isolate, actinomycete strain K97-0003. ESI mass spectrometry of actinohivin isolated from the culture filtrate showed an ion with molecular mass of 12,520.3 Da. The amino acid sequence was determined by N-terminal Edman degradation of the intact protein and peptide fragments formed by endoproteinase digestions. Actinohivin consists of a 114-amino-acid chain that exhibits internal sequence triplication. Actinohivin inhibited both T-cell and macrophage tropic syncytium formation, with IC(50) values of 60 and 700 nM, respectively, and the cytopathic effect of HIV-1(IIIB) in MT-4 cells, with IC(50) value of 230 nM.

Multiple drug rescue therapy for HIV-infected individuals with prior virologic failure to multiple regimens

OBJECTIVES

To characterize the antiviral response and tolerability of a multi-drug rescue therapy (MDRT) among heavily pretreated patients.

METHODS

Observational study conducted in a single, university-based tertiary referral clinic. Patients (n = 106) who failed several prior regimens started MDRT including at least five antiretroviral (ARV) drugs between August 1997 and June 1998. The most common starting regimen included three nucleoside reverse transcriptase inhibitors and two protease inhibitors, which was prescribed to 45 (42.5%) patients. Virologic response was defined as plasma viral load < 400 copies/ml on at least two consecutive visits.

RESULTS

Median prior ARV exposure was seven drugs over a median time of 43 months. Fifty-nine percent of the patients were phenotypically (VIRCO Antivirogram) resistant at baseline to seven or more ARV. Median plasma viral load change following initiation of MDRT was -1.04 log10 copies/ml over a median of 15 months. Using intention-to-treat analysis 40% of patients had plasma viral load values < 400 copies/ml between weeks 47 and 57 of follow-up. Twenty-six patients (25%) experienced severe laboratory abnormalities or subjective adverse drug effects and six of these participants discontinued therapy.

CONCLUSION

MDRT induced a substantial antiviral response in this heavily pretreated group of patients despite extensive phenotypic resistance at baseline. Adverse effects were frequent but generally manageable. Our data suggest that relying exclusively on historical, clinical and laboratory evidence may not be sufficient to rule out a possible antiviral response when multiple drug regimens are used in this heavily pretreated patient population.

Inosine and 2'-deoxyinosine and their synthetic analogues: lipophilicity in the relation to their retention in reversed-phase liquid chromatography and the stability characteristics

The purines and among them inosine synthetic nucleoside derivatives and analogues belong to a group of compounds to which the attention is being paid because of their biological activities. Relationships of their various parameters are being investigated because of their effect on biological (antineoplastic, virostatic, immunosuppressive) properties. Hydrophobicity parameters expressed as the logarithm of the partition coefficient (log P) and the capacity factor k' for naturally occurring inosine, 2'-deoxyinosine, 2'-deoxyadenosine and 2'-deoxyguanosine and for inosine synthetic analogues 5'-deoxyinosine, 5'-chloro-5'-deoxyinosine and 2',3'-dideoxyinosine were measured. The effect of methanol percentage in the mobile phase and its pH on the retention of the studied compounds in a reversed-phase system was also examined. There was a good correlation between the lipophilicity expressed as log P and capacity factor k'. It was also determined that dissociation has a marginal effect on capacity factor k' in this group of nucleoside derivatives as the k' values were almost unchanged at various pH of the mobile phase used. The stability of the all investigated compounds was investigated in basic, neutral and acidic conditions. The values of the reaction constant k1 were calculated and effects of nucleoside structural characteristic on stability are discussed.

The cost effectiveness of antiretroviral regimens for the treatment of HIV/AIDS

OBJECTIVE

To estimate survival, the number of life-years gained and cost effectiveness of antiretroviral therapy (ART) regimens, denoted as ERA-I [zidovudine + (didanosine or zalcitabine)]; ERA-II [stavudine + (didanosine or zalcitabine) or lamivudine + (zidovudine or didanosine or zalcitabine or stavudine)]; and ERA-III [2 nucleoside reverse transcriptase inhibitors + (1 protease inhibitor or 1 non-nucleoside reverse transcriptase inhibitor)].

DESIGN

Modelling of drug cost, cost of opportunistic diseases and survival of HIV positive men and women in the province of British Columbia who were first prescribed any ART between October 1992 and June 1996. A 'reference cohort' was modelled upon individuals in a longitudinal cohort of homosexual men followed since 1982. PERSPECTIVE AND SETTING: Third-party payer perspective in British Columbia, Canada.

PATIENTS

All HIV-positive men and women aged > or =18 years with CD4+ counts < or =350 cells/microL who were enrolled in the province-wide drug treatment programme.

MAIN OUTCOME MEASURES

Annual costs, survival and cost-effectiveness ratios of successive ART regimens.

RESULTS

Total costs [1997 Canadian dollars ($Can)] at 12 months under ERA-I, -II and -III were $Can4897, $Can6620 and $Can 11 914, respectively. Survival at 12 months under ERA-I, -II and -III was 89.6%, 91.0% and 97.6%, respectively. The annual incremental cost (estimated by the total incremental cost at 12 months) between ERA-II and ERA-I was $Can1723. The incremental cost-effectiveness ratios between ERA-III and ERA-I, and between ERA-III and ERA-II were $Can58 806 and $Can46 971 per life-year gained, respectively.

CONCLUSION

We found the cost effectiveness of ERA-III ART regimens well within the range of currently funded therapies for the treatment of other chronic diseases.

Full suppression of viral load is needed to achieve an optimal CD4 cell count response among patients on triple drug antiretroviral therapy

OBJECTIVE

To characterize the relationship between plasma viral load (pVL) suppression and triple drug antiretroviral therapy, and the accompanying changes in CD4 cell counts.

METHOD

Retrospective study of 465 participants in a HIV/AIDS Treatment Program who initiated triple drug therapy between August 1996 and May 1998. Participants were divided into three groups according to their pVL response: (i) non-responders (NR; n = 112) exhibited pVL persistently > 500 copies/ml over the study period; (ii) partial responders (PR; n = 100) achieved a pVL < 100 copies/ml at least once and subsequently rebounded to > 500 copies/ml; and (iii) full responders (FR; n = 253) achieved a pVL < 500 copies/ml and sustained this level for the remainder of the study period. For each group, the accompanying changes in absolute and fractional CD4 cell counts were evaluated.

RESULTS

The median net change in pVL per person from baseline to the end of the observation period was -0.37, -2.27, and -2.56 log10 copies/ml for NR, PR and FR, respectively. During weeks 68-83, the median CD4 cell count (x 10(6) cells/l) was 150 [interquartile range (IQR) 90-370], 380 (IQR 300-480) and 525 (IQR 305-705) for NR, PR and FR, respectively. Median changes in CD4 cells (x 10(6) cells/l) were -20 (IQR -90 to 40), 150 (IQR 30-250) and 240 (IQR 110-365) for NR, PR, and FR, respectively. The net percentage change in CD4 cells per person was 0% (IQR -34-31), 54% (IQR 6-160), and 83% (IQR 39-173) for NR, PR, and FR, respectively. By weeks 68-83, the median fractional CD4 cells was 0.16 (IQR 0.07-0.22), 0.22 (IQR 0.15-0.28), and 0.26 (IQR 0.17-0.34) for NR, PR and FR respectively.

CONCLUSIONS

An optimal CD4 cell count response appears to be coupled with continued pVL suppression. Our data indicate that maximal suppression of viral replication should remain the primary goal of therapy.

Modern antiretroviral therapy improves life expectancy of gay and bisexual males in Vancouver's West End

This study was undertaken to evaluate the life expectancy of gay and bisexual men in the West End of Vancouver, British Columbia during two time periods. Mortality data for males were obtained for the periods 1990 to 1992 and 1995 to 1997 and population estimates were obtained from the 1991 and 1996 Census. The proportion of the male population over 20 years of age estimated to be gay and bisexual was derived from a random telephone survey. Mortality patterns were assessed by comparing changes in life expectancy at age 20 years between the periods, and by examining the life expectancy lost attributed to HIV/AIDS. Between the periods there was 3.8 +/- 3.4 years increase in life expectancy among gay and bisexual men. At exact age 20 years, life expectancy increased from 37.0 +/- 3.5 years during the period 1990 to 1992 to 40.8 +/- 2.4 years during the period 1995 to 1997. The loss of life expectancy attributed to HIV/AIDS at this age was 13.8 +/- 3.9 during the first period and 9.8 +/- 3.6 years during the second period. This gain is most likely the result of the improved efficacy of antiretroviral therapies.

Extent to which low-level use of antiretroviral treatment could curb the AIDS epidemic in sub-Saharan Africa

BACKGROUND

Despite growing international pressure to provide HIV-1 treatment to less-developed countries, potential demographic and epidemiological impacts have yet to be characterised. We modelled the future impact of antiretroviral use in South Africa from 2000 to 2005.

METHODS

We produced a population projection model that assumed zero antiretroviral use to estimate the future demographic impacts of the HIV-1 epidemic. We also constructed four antiretroviral-adjusted scenarios to estimate the potential effect of antiretroviral use. We modelled total drug cost, cost per life-year gained, and the proportion of per-person health-care expenditure required to finance antiretroviral treatment in each scenario.

FINDINGS

With no antiretroviral use between 2000 and 2005, there will be about 276,000 cumulative HIV-1-positive births, 2,302,000 cumulative new AIDS cases, and the life expectancy at birth will be 46.6 years by 2005. By contrast, 110,000 HIV-1-positive births could be prevented by short-course antiretroviral prophylaxis, as well as a decline of up to 1 year of life expectancy. The direct drug costs of universal coverage for this intervention would be US$54 million--less than 0.001% of the per-person health-care expenditure. In comparison, triple-combination treatment for 25% of the HIV-1-positive population could prevent a 3.1-year decline in life expectancy and more than 430,000 incident AIDS cases. The drug costs of this intervention would, however, be more than $19 billion at present prices, and would require 12.5% of the country's per-person health-care expenditure.

INTERPRETATION

Although there are barriers to widespread HIV-1 treatment, limited use of antiretrovirals could have an immediate and substantial impact on South Africa's AIDS epidemic.

Antiretroviral medication use among injection drug users: two potential futures

OBJECTIVE

To model the potential impact of HIV infection rates and the use of antiretroviral medication on life expectancy and mortality in the Downtown Eastside of Vancouver, British Columbia, Canada, from 1999 to 2006.

DESIGN

Population projections were made to estimate the population of the Downtown Eastside in the year 2006.

METHODS

Two scenarios were modelled to predict the impact of HIV infection and antiretroviral use on mortality and life expectancy. The use of antiretroviral therapy was estimated to be 80% in the first scenario and 20% in the second. The prevalence of HIV by age and sex, and by year infected was estimated using data from the Vancouver Injection Drug User Study.

RESULTS

If the level of antiretroviral therapy use among HIV-positive individuals was 80% at baseline, then we estimate that the life expectancy at birth in the year 2006 will be 60.8 years for men and 72.8 years for women, and 172 AIDS deaths will occur between 1999 and 2006. In contrast, if the present level of antiretroviral medication use persists, the life expectancy at birth in the year 2006 will be 56.9 years for men and 68.6 years for women, and 503 AIDS deaths will occur between 1999 and 2006.

CONCLUSION

Our analysis suggests that if the low levels of antiretroviral therapy use persist, life expectancy in Vancouver's Downtown Eastside will soon be on a par with many of the world's least developed countries. Our findings highlight the large health status decline that can be expected in many inner city neighbourhoods if low levels of antiretroviral use persist. Although reasonable coverage targets for injection drug users (IDU) have not been established, the expanded use of antiretroviral medication is urgently needed to avert a drastic decline in health status.