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Concept: CD4

175

Global programs of anti-HIV treatment depend on sustained laboratory capacity to assess treatment initiation thresholds and treatment response over time. Currently, there is no valid alternative to CD4 count testing for monitoring immunologic responses to treatment, but laboratory cost and capacity limit access to CD4 testing in resource-constrained settings. Thus, methods to prioritize patients for CD4 count testing could improve treatment monitoring by optimizing resource allocation.

Concepts: Retrospective, Economics, CD4, Resource allocation, Resource, Allocation of resources

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BACKGROUND: Decisions about when to start an antiretroviral therapy (ART) are normally based on CD4 cell counts and viral load (VL). However, these measurements require equipment beyond the capacity of most laboratories in low-income and middle-income settings. Thus, there is an urgent need to identify and test simple markers to guide the optimal time for starting and for monitoring the effect of ART in developing countries. OBJECTIVES: (1) To evaluate anthropometric measurements and measurement of plasma-soluble form of the urokinase plasminogen activator receptor (suPAR) levels as potential risk factors for early mortality among HIV-infected patients; (2) to assess whether these markers could help identify patients to whom ART should be prioritised and (3) to determine if these markers may add information to CD4 cell count when VL is not available. DESIGN: An observational study. SETTING: The largest ART centre in Bissau, Guinea-Bissau. PARTICIPANTS: 1083 ART-naïve HIV-infected patients. OUTCOME MEASURES: Associations between baseline anthropometric measurements, CD4 cell counts, plasma suPAR levels and survival were examined using Cox proportional hazards models. RESULTS: Low body mass index (BMI≤18.5 kg/m(2)), low mid-upper-arm-circumference (MUAC≤250 mm), low CD4 cell count (≤350 cells/μl) and high suPAR plasma levels (>5.3 ng/ml) were independent predictors of death. Furthermore, mortality among patients with low CD4 cell count, low MUAC or low BMI was concentrated in the highest suPAR quartile. CONCLUSIONS: Irrespective of ART initiation and baseline CD4 count, MUAC and suPAR plasma levels were independent predictors of early mortality in this urban cohort. These markers could be useful in identifying patients at the highest risk of short-term mortality and may aid triage for ART when CD4 cell count is not available or when there is shortness of antiretroviral drugs.

Concepts: Antiretroviral drug, HIV, AIDS, Viral load, Body mass index, CD4, Antiretroviral drugs, Urokinase receptor

28

BACKGROUND: HIV-1 group M viruses diverge 25%-35% in envelope, important for viral attachment during infection, and 10-15% in the pol region, under selection pressure from common antiretrovirals. In Asia, subtypes B and CRF01_AE are common genotypes. Our objectives were to determine whether clinical, immunologic or virologic treatment responses differed by genotype in treatment-naïve patients initiating first-line therapy. METHODS: Prospectively collected, longitudinal data from patients in Thailand, Hong Kong, Malaysia, Japan, Taiwan and South Korea were provided for analysis. Covariates included demographics, hepatitis B and C coinfections, baseline CD4 T lymphocyte count and plasma HIV-1 RNA levels. Clinical deterioration (a new diagnosis of CDC category B/AIDS-defining illness or death) was assessed by proportional hazards models. Surrogate endpoints were 12-month change in CD4 cell count and virologic suppression post-therapy, evaluated by linear and logistic regression, respectively. RESULTS: Of 1105 patients, 1036 (93.8%) infected with CRF01_AE or subtype B were eligible for inclusion in clinical deterioration analyses and contributed 1546.7 person-years of follow-up (median:413 days, IQR:169-672 days). Patients >40 years demonstrated smaller immunological increases (p=0.002) and higher risk of clinical deterioration (HR=2.17; p=0.008). Patients with baseline CD4 cell counts >200 cells/μL had lower risk of clinical deterioration (HR=0.373; p=0.003). A total of 532 patients (48.1% of eligible) had CD4 counts available at baseline and 12 months post-therapy for inclusion in immunolgic analyses. Patients infected with subtype B had larger increases in CD4 counts at 12 months (p=0.024). A total of 530 patients (48.0% of eligible) were included in virologic analyses with no differences in response found between genotypes. CONCLUSIONS: Results suggest that patients infected with CRF01_AE have reduced immunologic response to therapy at 12 months, compared to subtype-B-infected counterparts. Clinical deterioration was associated with low baseline CD4 counts and older age. The lack of differences in virologic outcomes suggests that all patients have opportunities for virologic suppression.

Concepts: HIV, Immune system, Lymphocyte, B cell, Subtypes of HIV, CD4, Thymus, Complete blood count

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It is essential to discover and develop small-molecule HIV-1 entry inhibitors with suitable pharmaceutical properties. Areas covered: We review the development of small-molecule HIV-1 entry inhibitors as evidenced in patents, patent applications, and related research articles published between 2010 and 2015. Expert opinion: HIV-1 Env gp120 and gp41 are important targets for development of HIV-1 entry inhibitors. The Phe43 pocket in gp120 and the highly conserved hydrophobic pocket on gp41 NHR-trimer are important targets for identification of HIV-1 attachment and fusion inhibitors, respectively. Compounds that bind to Phe43 pocket can block viral gp120 binding to CD4 on T cells, thus inhibiting HIV-1 attachment. However, most compounds targeting Phe43 pocket identified so far are HIV-1 entry agonists with the ability to enhance infectivity of HIV-1 in CD4-negative cells. Therefore, it is essential to identify HIV-1 entry antagonist-based HIV-1 attachment/entry inhibitors. Compounds binding to the gp41 hydrophobic pocket may inhibit CHR binding to the gp41 NHR trimer, thus blocking six-helix bundle formation and gp41-mediated virus-cell fusion. However, most lead compounds targeting this pocket have low potency, possibly because the pocket is too big or too deep. Therefore, it is necessary to identify other pockets in gp41 for developing HIV-1 fusion/entry inhibitors.

Concepts: HIV, CCR5, Enzyme inhibitor, Inhibitor, CD4, Xanthine oxidase inhibitor, Patent, Gp41

3

Matthew Fox and Sydney Rosen discuss a cascade of HIV care adapted to WHO-recommended antiretroviral therapy irrespective of CD4 cell count.

Concepts: Antiretroviral drug, HIV, AIDS, Protease inhibitor, Immune system, Viral load, CD4, Network Ten

3

2

Certain prescribed opioids have immunosuppressive properties, yet their impact on clinically relevant outcomes, including antiretroviral therapy (ART) response among HIV-infected patients, remains understudied.

Concepts: Antiretroviral drug, HIV, AIDS, T helper cell, CD4

2

In Africa, antiretroviral therapy (ART) is delivered with limited laboratory monitoring, often none. In 2003-2004, investigators in the Development of Antiretroviral Therapy in Africa (DART) Trial randomized persons initiating ART in Uganda and Zimbabwe to either laboratory and clinical monitoring (LCM) or clinically driven monitoring (CDM). CD4 cell counts were measured every 12 weeks in both groups but were only returned to treating clinicians for management in the LCM group. Follow-up continued through 2008. In observational analyses, dynamic marginal structural models on pooled randomized groups were used to estimate survival under different monitoring-frequency and clinical/immunological switching strategies. Assumptions included no direct effect of randomized group on mortality or confounders and no unmeasured confounders which influenced treatment switch and mortality or treatment switch and time-dependent covariates. After 48 weeks of first-line ART, 2,946 individuals contributed 11,351 person-years of follow-up, 625 switches, and 179 deaths. The estimated survival probability after a further 240 weeks for post-48-week switch at the first CD4 cell count less than 100 cells/mm(3) or non-Candida World Health Organization stage 4 event (with CD4 count <250) was 0.96 (95% confidence interval (CI): 0.94, 0.97) with 12-weekly CD4 testing, 0.96 (95% CI: 0.95, 0.97) with 24-weekly CD4 testing, 0.95 (95% CI: 0.93, 0.96) with a single CD4 test at 48 weeks (baseline), and 0.92 (95% CI: 0.91, 0.94) with no CD4 testing. Comparing randomized groups by 48-week CD4 count, the mortality risk associated with CDM versus LCM was greater in persons with CD4 counts of <100 (hazard ratio = 2.4, 95% CI: 1.3, 4.3) than in those with CD4 counts of ≥100 (hazard ratio = 1.1, 95% CI: 0.8, 1.7; interaction P = 0.04). These findings support a benefit from identifying patients immunologically failing first-line ART at 48 weeks.

Concepts: Antiretroviral drug, HIV, AIDS, Africa, Count, CD4, Covariate, Time-varying covariate

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HIV disease staging with referral laboratory-based CD4 cell count testing is a key barrier to the initiation of antiretroviral treatment (ART). Point-of-care CD4 cell counts can improve linkage to HIV care among people living with HIV, but its effect has not been assessed with a randomised controlled trial in the context of home-based HIV counselling and testing (HBCT).

Concepts: Antiretroviral drug, HIV, AIDS, Protease inhibitor, Viral load, Gene, Randomized controlled trial, CD4

1

In late 2009 US guidelines for HIV treatment were revised to recommend the initiation of combination antiretroviral therapy (cART) earlier in the course of the disease. We analyzed the life expectancy gains of people infected with HIV between the introduction of cART in 1996 and the 2009 guideline revisions. Compared to people who initiated cART late (defined as having a CD4 cell count of less than 350 per cubic millimeter of blood), those who initiated treatment early (with a CD4 count of 350-500) could expect to live 6.1 years longer, and the earliest initiators (with a CD4 count of more than 500) could expect an extra 9.0 years of life. The total value of life expectancy gains to the early and earliest initiators of treatment was $80 billion, with each life-year valued at $150,000. The value of the survival gains was more than double the increase in drug manufacturers' revenues from early cART initiation. Our results clarify the economic implications of adherence to treatment guidelines.

Concepts: Antiretroviral drug, HIV, AIDS, Protease inhibitor, Viral load, Life, Initiation, CD4