Synthesis of 3′-O-Propargylthymidine as a Candidate Antiretroviral Agent

Abstract

3′-O-Propargylthymidinc, which may be viewed as a stnictural analogue of the potent antiretroviral agent 3′-azido-3′-deoxythymidine (AZT), was synthesized from 5′-O-(4,4′-dimethoxytritylthymidine by reaction with propargyl bromide followed by gentle acidolysis. The 3′-O-propargyl derivative was tested for antiretroviral activity in SC-1 mouse fibroblasts infected with Rauscher murine leukemia virus (MuLV). No inhibition of MuLV proliferation was observed at concentrations of 3′-O-propargylthymidine from 0.001 to 100 μM. whereas the IC₅₀ against the host cells was 30 μM. By comparison, AZT had an IC₅₀ for MuLV growth of 0.01 μM and an IC₅₀ for cell growth of >100 μM. Thus, replacement of the 3′-N-N≡N group in AZT by a 3′-OCH₂C≡CH group increased cytotoxicity but decreased antiretroviral activity relative to AZT.     

Increases in Pediatric Antiretroviral Treatment,South Africa 2005–2010

Background

In South Africa in 2010, about 340,000 children under the age of 15 were infected with HIV. We describe the increase in the treatment of South African pediatric HIV-infected patients assisted by the President’s Emergency Plan for AIDS Relief (PEPFAR) from 2004 to 2010.

Methods

We reviewed routine program data from PEPFAR-funded implementing partners among persons receiving antiretroviral treatment age 15 years old and less. Data quality was assessed during the reporting period by program officials through routine analysis of trends and logic checks. Based on UNAIDS estimated mortality rates of untreated HIV-infected children, we calculated the number of deaths averted and life-years gained in children under five receiving PEPFAR-assisted antiretroviral treatment.

Results

From October 2004 through September 2010, the number of children newly initiated on antiretroviral treatment in PEPFAR-assisted programs increased from 154 to 2,641 per month resulting in an increase from 2,412 children on antiretroviral treatment in September 2005 to 79,416 children in September 2010. Of those children who initiated antiretroviral treatment before September 2009, 0–4 year olds were 1.4 (95% CI: 1.3–1.5) times as likely to transfer out of the program or die as 5–14 year olds; males were 1.3 (95% CI: 1.0–1.7) times as likely to stop treatment as females. Approximately 27,548 years of life were added to children under-five years old from PEPFAR-assisted antiretroviral treatment.

Conclusions

Pediatric antiretroviral treatment in South Africa has increased substantially. However, additional case-finding and a further acceleration in the implementation of pediatric care and treatment services is required to meet the current treatment need.     

When Should Children with HIV Infection Be Started on Antiretroviral Therapy?

Background to the debate: The advent of highly active antiretroviral therapy (HAART) dramatically improved the prognosis for both adults and children infected with HIV who had access to treatment. However, the optimal timing for initiating treatment remains controversial, particularly in children. This debate lays out the case for deferred treatment against the case for early initiation of HAART in children.     

As Good As It Gets? The Problem of HIV Persistence despite Antiretroviral Drugs

Human immunodeficienty virus (HIV) infection is suppressed but not eliminated by antiretroviral drugs.?Viral?persistence in the face of therapy has been explained by viral latency, lowered effectiveness of drugs?in some anatomical sites and cell types, and cell-to-cell spread. These mechanisms allow for drug-sensitive virus to persist despite treatment. Understanding the persistence mechanism at work at?different times after infection, including the time of initial infection immediately following transmission?when reservoirs are first formed, will reveal if we are at the limit of what can be achieved with the?current therapy paradigm of suppressing ongoing virus replication with drugs. We discuss some of?the possible reasons why HIV persists at different points on the infection timeline, focusing on the?role ongoing replication may have in maintaining the infection despite drugs at early times postexposure.     

What Happens to Patients on Antiretroviral Therapy Who Transfer Out to Another Facility?

Background

Long term retention of patients on antiretroviral therapy (ART) in Africa''s rapidly expanding programmes is said to be 60% at 2 years. Many reports from African ART programmes make little mention of patients who are transferred out to another facility, yet Malawi''s national figures show a transfer out of 9%. There is no published information about what happens to patients who transfer-out, but this is important because if they transfer-in and stay alive in these other facilities then national retention figures will be better than previously reported.

Methodology/Principal Findings

Of all patients started on ART over a three year period in Mzuzu Central Hospital, North Region, Malawi, those who transferred out were identified from the ART register and master cards. Clinic staff attempted to trace these patients to determine whether they had transferred in to a new ART facility and their outcome status. There were 805 patients (19% of the total cohort) who transferred out, of whom 737 (92%) were traced as having transferred in to a new ART facility, with a median time of 1.3 months between transferring-out and transferring-in. Survival probability was superior and deaths were lower in the transfer-out patients compared with those who did not transfer.

Conclusion/Significance

In Mzuzu Central Hospital, patients who transfer-out constitute a large proportion of patients not retained on ART at their original clinic of registration. Good documentation of transfer-outs and transfer-ins are needed to keep track of national outcomes. Furthermore, the current practice of regarding transfer-outs as being double counted in national cohorts and subtracting this number from the total national registrations to get the number of new patients started on ART is correct.     

Trends in Antiretroviral Therapy and Prevalence of HIV Drug Resistance Mutations in Sweden 1997–2011

Objective

Describe trends in antiretroviral treatments and drug resistance mutations among Swedish HIV-patients over time 1997–2011.

Methods

Treatment histories, viral sequences, and demographic and clinical data were retrieved from the national database InfCareHIV. All ART-experienced patients were included (N = 6537), while resistance tests were restricted to those obtained ≥90 days after ART start. This cohort is fully representative for Sweden since the database covers virtually all diagnosed HIV-patients since the start of the epidemic. Patients were grouped according to the year of first ART, and treatments and mutations were analyzed by calendar year.

Results

The prevalence of major drug resistance mutations decreased dramatically over time, most rapidly between 2003 and 2007. Since then there has been a continued slow decrease for NRTI- and PI-associated mutations with an overall prevalence among all ART-experienced patients at 1.1% (NRTI) and 0.3% (PI) in 2011. NNRTI resistance reached the lowest level in 2007–2009 (0.6%), but is now increasing (0.9% in 2011). Patients with first ART exposure before 2001 are still highly overrepresented among those with PI and, to a lesser extent, NRTI resistance. In contrast, almost half of the patients with NNRTI mutations in 2011 initiated their first ART after 2007.

Conclusions

Tremendous improvements in ART options and knowledge have resulted in rapidly declining levels of resistance, and most of the current NRTI and PI mutations are found among patients with a history of suboptimal treatments. However, NNRTI resistance is increasing and is primarily found in patients infected in low- and middle-income countries who initiated ART in recent years. It is plausible that these patients were infected with resistant strains and it is therefore suggested that resource-rich countries like Sweden should test for resistance in minor quasispecies or use PI-based first-line regimens in patients who are at increased risk of carrying resistant virus.     

Synthesis and Antiretroviral Activity of Novel 4′-Fluoro-5′-Deoxyphosphonic Acid Carbocyclic Nucleoside Analogs

Novel 5′-deoxycarbocyclic purine phosphonic acid analogs with the 4′-electropositive moiety, fluorine were designed, and synthesized from glyceraldehyde. The cyclopentenol intermediate, 9, was successfully synthesized by the ring-closing metathesis of divinyl 8. The condensation reaction of cyclopentanol 15 with purine bases under Mitsunobu conditions successfully afforded the desired phosphonate analogs. The synthesized nucleoside phosphonic acid analogs, 19, 22, 26, and 29, were subjected to antiviral screening against human immunodeficiency virus (HIV)-1. Guanine phosphonic acid analog 29 showed significant anti-HIV activity (EC₅₀ = 10.3 μM).     

HIV Cure Strategies: How Good Must They Be to Improve on Current Antiretroviral Therapy?

Background

We examined efficacy, toxicity, relapse, cost, and quality-of-life thresholds of hypothetical HIV cure interventions that would make them cost-effective compared to life-long antiretroviral therapy (ART).

Methods

We used a computer simulation model to assess three HIV cure strategies: Gene Therapy, Chemotherapy, and Stem Cell Transplantation (SCT), each compared to ART. Efficacy and cost parameters were varied widely in sensitivity analysis. Outcomes included quality-adjusted life expectancy, lifetime cost, and cost-effectiveness in dollars/quality-adjusted life year ($/QALY) gained. Strategies were deemed cost-effective with incremental cost-effectiveness ratios <$100,000/QALY.

Results

For patients on ART, discounted quality-adjusted life expectancy was 16.4 years and lifetime costs were $591,400. Gene Therapy was cost-effective with efficacy of 10%, relapse rate 0.5%/month, and cost $54,000. Chemotherapy was cost-effective with efficacy of 88%, relapse rate 0.5%/month, and cost $12,400/month for 24 months. At $150,000/procedure, SCT was cost-effective with efficacy of 79% and relapse rate 0.5%/month. Moderate efficacy increases and cost reductions made Gene Therapy cost-saving, but substantial efficacy/cost changes were needed to make Chemotherapy or SCT cost-saving.

Conclusions

Depending on efficacy, relapse rate, and cost, cure strategies could be cost-effective compared to current ART and potentially cost-saving. These results may help provide performance targets for developing cure strategies for HIV.     

HIV-1 Superinfection in the Antiretroviral Therapy Era: Are Seroconcordant Sexual Partners at Risk?

Background

Acquisition of more than one strain of human immunodeficiency virus type 1 (HIV-1) has been reported to occur both during and after primary infection, but the risks and repercussions of dual and superinfection are incompletely understood. In this study, we evaluated a longitudinal cohort of chronically HIV-infected men who were sexual partners to determine if individuals acquired their partners'' viral strains.

Methodology

Our cohort of HIV-positive men consisted of 8 couples that identified themselves as long-term sexual partners. Viral sequences were isolated from each subject and analyzed using phylogenetic methods. In addition, strain-specific PCR allowed us to search for partners'' viruses present at low levels. Finally, we used computational algorithms to evaluate for recombination between partners'' viral strains.

Principal Findings/Conclusions

All couples had at least one factor associated with increased risk for acquisition of new HIV strains during the study, including detectable plasma viral load, sexually transmitted infections, and unprotected sex. One subject was dually HIV-1 infected, but neither strain corresponded to that of his partner. Three couples'' sequences formed monophyletic clusters at the entry visit, with phylogenetic analysis suggesting that one member of the couple had acquired an HIV strain from his identified partner or that both had acquired it from the same source outside their partnership. The 5 remaining couples initially displayed no evidence of dual infection, using phylogenetic analysis and strain-specific PCR. However, in 1 of these couples, further analysis revealed recombinant viral strains with segments of viral genomes in one subject that may have derived from the enrolled partner. Thus, chronically HIV-1 infected individuals may become superinfected with additional HIV strains from their seroconcordant sexual partners. In some cases, HIV-1 superinfection may become apparent when recombinant viral strains are detected.     

The Financial Burden of Morbidity in HIV-Infected Adults on Antiretroviral Therapy in C?te d'Ivoire

Background

Large HIV care programs frequently subsidize antiretroviral (ARV) drugs and CD4 tests, but patients must often pay for other health-related drugs and services. We estimated the financial burden of health care for households with HIV-infected adults taking antiretroviral therapy (ART) in Côte d''Ivoire.

Methodology/Principal Findings

We conducted a cross-sectional survey. After obtaining informed consent, we interviewed HIV-infected adults taking ART who had consecutively attended one of 18 HIV care facilities in Abidjan. We collected information on socioeconomic and medical characteristics. The main economic indicators were household capacity-to-pay (overall expenses minus food expenses), and health care expenditures. The primary outcome was the percentage of households confronted with catastrophic health expenditures (health expenditures were defined as catastrophic if they were greater than or equal to 40% of the capacity-to-pay). We recruited 1,190 adults. Median CD4 count was 187/mm³, median time on ART was 14 months, and 72% of subjects were women. Mean household capacity-to-pay was $213.7/month, mean health expenditures were $24.3/month, and 12.3% of households faced catastrophic health expenditures. Of the health expenditures, 75.3% were for the study subject (ARV drugs and CD4 tests, 24.6%; morbidity events diagnosis and treatment, 50.1%; transportation to HIV care centres, 25.3%) and 24.7% were for other household members. When we stratified by most recent CD4 count, morbidity events related expenses were significantly lower when subjects had higher CD4 counts.

Conclusions/Significance

Many households in Côte d''Ivoire face catastrophic health expenditures that are not attributable to ARV drugs or routine follow-up tests. Innovative schemes should be developed to help HIV-infected patients on ART face the cost of morbidity events.     

Probiotics Reduce Inflammation in Antiretroviral Treated,HIV-Infected Individuals: Results of the “Probio-HIV” Clinical Trial

Background

HIV infection results in damage to the gastrointestinal (GI) tract, microbial translocation and immune activation. These are not completely normalized with combined antiretroviral therapy (cART). Moreover, increate morbidity and mortality of cART-treated HIV-infected individuals is associated with inflammation.

Methods

In order to enhance GI tract immunity, we recruited and treated 20 HIV-infected humans with cART supplemented with probiotics and followed inflammation and immunological parameters (clinical trial number NCT02164344). 11 HIV seronegative subjects were included as control group. The enumeration of CD4+, CD8+, CD38+ and HLA-DR+ lymphocytes were evaluated on peripheral blood; HIV-RNA levels, sCD14, d-dimer, C-reactive protein (CRP) high sensitivity C-reactive protein (hsCRP), IL-6 and Lipopolysaccharide Binding Protein (LBP) were assayed on plasma.

Results

We observe that cART does not normalize the levels of immune activation in HIV positive patients anyway inflammation and markers of microbial translocation were significantly reduced with probiotic supplementation. Patients show a clear and statistically significant reduction in the levels of immune activation on CD4 T-lymphocytes, for both markers CD38 and HLA-DR and their simultaneous expression, LBP and hsCRP plasma levels after probiotic diet supplementation settling to values comparable to controls.

Conclusions

Supplementing cART with probiotics in HIV-infected individuals may improve GI tract immunity and there by mitigate inflammatory sequelae, ultimately improving prognosis.

Trial Registration

ClinicalTrials.gov NCT02164344     

Initiating Antiretroviral Therapy for HIV at a Patient’s First Clinic Visit: The RapIT Randomized Controlled Trial

BackgroundHigh rates of patient attrition from care between HIV testing and antiretroviral therapy (ART) initiation have been documented in sub-Saharan Africa, contributing to persistently low CD4 cell counts at treatment initiation. One reason for this is that starting ART in many countries is a lengthy and burdensome process, imposing long waits and multiple clinic visits on patients. We estimated the effect on uptake of ART and viral suppression of an accelerated initiation algorithm that allowed treatment-eligible patients to be dispensed their first supply of antiretroviral medications on the day of their first HIV-related clinic visit.ConclusionsOffering single-visit ART initiation to adult patients in South Africa increased uptake of ART by 36% and viral suppression by 26%. This intervention should be considered for adoption in the public sector in Africa.

Trial Registration

ClinicalTrials.gov {"type":"clinical-trial","attrs":{"text":"NCT01710397","term_id":"NCT01710397"}}NCT01710397, and South African National Clinical Trials Register DOH-27-0213-4177.     

HIV Treatment as Prevention: Modelling the Cost of Antiretroviral Treatment��State of the Art and Future Directions

Policy discussions about the feasibility of massively scaling up antiretroviral therapy (ART) to reduce HIV transmission and incidence hinge on accurately projecting the cost of such scale-up in comparison to the benefits from reduced HIV incidence and mortality. We review the available literature on modelled estimates of the cost of providing ART to different populations around the world, and suggest alternative methods of characterising cost when modelling several decades into the future. In past economic analyses of ART provision, costs were often assumed to vary by disease stage and treatment regimen, but for treatment as prevention, in particular, most analyses assume a uniform cost per patient. This approach disregards variables that can affect unit cost, such as differences in factor prices (i.e., the prices of supplies and services) and the scale and scope of operations (i.e., the sizes and types of facilities providing ART). We discuss several of these variables, and then present a worked example of a flexible cost function used to determine the effect of scale on the cost of a proposed scale-up of treatment as prevention in South Africa. Adjusting previously estimated costs of universal testing and treatment in South Africa for diseconomies of small scale, i.e., more patients being treated in smaller facilities, adds 42% to the expected future cost of the intervention.     

Decreased NK Cell FcRγ in HIV-1 Infected Individuals Receiving Combination Antiretroviral Therapy: a Cross Sectional Study

Background

FcRγ is an immunoreceptor tyrosine-based activation motif (ITAM)-signalling protein essential for immunoreceptor signaling and monocyte, macrophage and NK cell function. Previous study from our laboratory showed that FcRγ is down-regulated in HIV-infected macrophages in vitro. FcRγ expression in immune cells present in HIV-infected individuals is unknown.

Methodology/Principal Findings

We compared FcRγ expression in peripheral blood mononuclear cells isolated from HIV-1-infected individuals receiving combination antiretroviral therapy and healthy, HIV-1-uninfected individuals. FcRγ mRNA and protein levels were measured using quantitative real-time PCR and immunoblotting, respectively. CD56⁺ CD94⁺ lymphocytes isolated from blood of HIV-1 infected individuals had reduced FcRγ protein expression compared to HIV-uninfected individuals (decrease = 76.8%, n = 18 and n = 12 respectively, p = 0.0036). In a second group of patients, highly purified NK cells had reduced FcRγ protein expression compared to uninfected controls (decrease = 50.2%, n = 9 and n = 8 respectively, p = 0.021). Decreased FcRγ expression in CD56+CD94+ lymphocytes was associated with reduced mRNA (51.7%, p = 0.021) but this was not observed for the smaller group of patients analysed for NK cell expression (p = 0.36).

Conclusion/Significance

These data suggest biochemical defects in ITAM-dependent signalling within NK cells in HIV-infected individuals which is present in the context of treatment with combination antiretroviral therapy.     

The Prevalence of HIV-1 Drug Resistance among Antiretroviral Treatment Na?ve Individuals in Mainland China: A Meta-Analysis

Background

Surveillance of drug resistance in antiretroviral treatment-naïve patients in China is needed to ensure optimal treatment outcomes and control of the human immunodeficiency virus (HIV) epidemic.

Methods

A systematic literature search was conducted in English and Chinese through PubMed (English), China National Knowledge Infrastructure (Chinese), Chinese Biomedical Literature Database (Chinese), and Wanfang (Chinese). Random effects models were used to calculate the pooled prevalence of transmitted drug resistance and subgroup analyses examined prevalence estimates across time periods, study locations, and study populations.

Results

Analysis of data from 71 studies (47 in Chinese and 24 in English) yielded a pooled prevalence of transmitted HIV drug resistance to any antiretroviral drug class of 3.64% (95% confidence interval [CI]: 3.00%–4.32%). Rates were significantly high at initial stage of free ART program from 2003 to 2005 (5.18%, 95%CI: 3.13%–7.63%), and were much lower among studies conducted in 2006–2008 (3.02%, 95%CI: 2.03%–4.16%). A slight increase was observed again in the most recent study period from 2009 to 2012 (3.68%, 95%CI: 2.78%–4.69%). Subgroup analysis revealed highest prevalence levels of transmitted drug resistance in Beijing city, and Henan and Hubei provinces (above 5%), and although differences in prevalence rates among risk groups were negligible, men who have sex with men were unique in their relatively large portion of protease inhibitor resistance, a second-line drug of limited availability in China.

Conclusions

Overall prevalence of transmitted HIV drug resistance in China is classified as “low” by the World Health Organization. However regional and temporal variability suggest a more complex epidemic for which closer HIV drug resistance surveillance is needed. A nationwide HIV drug resistance surveillance system to monitor both treatment-experienced and treatment-naïve patients will be a cornerstone to ensure the effectiveness of treatment scale-up, particularly as China seeks to expand a national policy of antiretroviral treatment as prevention.     

Renal Function Declines More in Tenofovir- than Abacavir-Based Antiretroviral Therapy in Low-Body Weight Treatment-Na?ve Patients with HIV Infection

Objective

To compare the rate of decline of renal function in tenofovir- and abacavir-based antiretroviral therapy (ART) in low-body weight treatment-naïve patients with HIV infection.

Design

We conducted a single-center retrospective cohort study of 503 Japanese patients who commenced on either tenofovir- or abacavir-based initial ART.

Methods

The incidence of renal dysfunction, defined as more than 25% fall in estimated glomerular filtration rate (eGFR) from the baseline, was determined in each group. The effect of tenofovir on renal dysfunction was estimated by univariate and multivariate Cox hazards models as the primary exposure. Changes in eGFR until 96 weeks were estimated in both groups with a repeated measures mixed model.

Results

The median body weight of the cohort was 64 kg. The estimated incidence of renal dysfunction in the tenofovir and the abacavir arm was 9.84 per 100 and 4.55 per 100 person-years, respectively. Tenofovir was significantly associated with renal dysfunction by univariate and multivariate analysis (HR = 1.747; 95% CI, 1.152–2.648; p = 0.009) (adjusted HR = 2.080; 95% CI, 1.339–3.232; p<0.001). In subgroup analysis of the patients stratified by intertertile baseline body weight, the effect of tenofovir on renal dysfunction was more evident in patients with lower baseline body weight by multivariate analysis (≤60 kg: adjusted HR = 2.771; 95%CI, 1.494–5.139; p = 0.001) (61–68 kg: adjusted HR = 1.908; 95%CI, 0.764–4.768; p = 0.167) (>68 kg: adjusted HR = 0.997; 95%CI, 0.318–3.121; p = 0.995). The fall in eGFR was significantly greater in the tenofovir arm than the abacavir arm after starting ART (p = 0.003).

Conclusion

The incidence of renal dysfunction in low body weight patients treated with tenofovir was twice as high as those treated with abacavir. Close monitoring of renal function is recommended for patients with small body weight especially those with baseline body weight <60 kg treated with tenofovir.     

Is Antiretroviral Therapy Causing Long-Term Liver Damage? A Comparative Analysis of HIV-Mono-Infected and HIV/Hepatitis C Co-Infected Cohorts

The effects of highly active antiretroviral therapy (HAART) on progression of hepatic fibrosis in HIV-hepatitis C virus (HCV) co-infection are not well understood. Deaths from liver diseases have risen in the post-HAART era, yet some cross-sectional studies have suggested that HAART use is associated with improved fibrosis rates. In a retrospective cohort of 533 HIV mono-infected and 127 HIV/HCV co-infected patients, followed between January 1991 and July 2005 at a university-based HIV clinic, we investigated the relationship between cumulative HAART exposure and hepatic fibrosis, as measured by the aspartate aminotransferase-to-platelet ratio index (APRI). We used a novel methodological approach to estimate the dose-response relationship of the effect of HAART exposure on APRI. HAART was associated with increasing APRI over time in HIV/HCV co-infected patients suggesting that they may be experiencing cumulative hepatotoxicity from antiretrovirals. The estimated median change (95% confidence interval) in APRI per one year of HAART intake was of −0.46% (−1.61% to 0.71%) in HIV mono-infected compared to 2.54% (−1.77% to 7.03%) in HIV/HCV co-infected patients. Similar results were found when the direct effect of HAART intake since the last visit was estimated on the change in APRI. HAART use associated is with increased APRI in patients with HIV/HCV co-infection. Therefore treatment for HCV infection may be required to slow the growing epidemic of end-stage liver disease in this population.