Evaluation of lymph node virus burden in human immunodeficiency virus-infected patients receiving efavirenz-based protease inhibitor--sparing highly active antiretroviral therapy

Antiretroviral (ARV) Properties Dictate Long-Acting Release and Tissue Partitioning Behaviors in Multidrug Subcutaneous Implants

Subcutaneous implants can provide patients with long-acting, compliance-independent drug dosing. For this reason, subcutaneous implants have shown emerging interest in human immunodeficiency virus (HIV) prevention. However, any successful long-acting HIV-prevention device will require multidrug dosing, which poses a challenge for formulation considering the physicochemically diverse selection of antiretroviral (ARV) candidates. As a method that has shown the capacity of efficient multidrug delivery, we assessed electrospun fiber implants composed of three synergistically potent ARVs and a biodegradable polymer selected by in vitro release studies. In mice, subcutaneous electrospun fiber implants exhibit burst release of the more hydrophilic drugs maraviroc (MVC) and raltegravir (RAL), which could be reduced via simple prewash treatments of the implants. Over an extended 120 day time frame, fiber implants show drug-specific differences in release time frames and magnitudes in blood serum. However, end-point drug tissue concentrations show that the most hydrophobic drug etravirine (ETR) remains in high concentrations within the implant and in local skin tissue biopsies. Furthermore, ETR is found to be capable of significant partitioning into lymph nodes, the lower female reproductive tract, and the rectum. Topologically smooth film implants also exhibit the same drug-dependent trends. Therefore, we illustrate that drug release and drug tissue partitioning are largely dictated by drug properties. Further, we find that the properties of ETR enable significant drug quantities within the tissues most relevant to HIV protection. Evidence from this work emphasizes the need for a greater focus on drug properties and prodrug strategies to enable relevant, extended, and targeted drug release.

Combining Cell and Gene Therapy in an Effort to Eradicate HIV

More than 30 million people are infected with HIV, and HIV remains the fifth leading cause of disability-adjusted life years worldwide. Antiretroviral therapy (ART) dramatically decreases mortality rate, but there are side effects, long-term toxicities, expenses, stigmas, and inconveniences associated with chronic treatment, and HIV-infected individuals on ART have an increased risk of malignancies, cardiovascular disease, neurologic disease, and shortened life expectancy. Therefore, a cure for HIV remains an important goal. Combining new cell and gene therapy technology is an exciting approach that appears promising in vitro. Animal testing and careful clinical trials will be needed to determine if these strategies are clinically useful.

Antiretroviral release from poly(DL-lactide-co-glycolide) nanoparticles in mice

OBJECTIVES

Free ritonavir, lopinavir and efavirenz injected intraperitoneally were compared with antiretroviral (AR) nanoparticles (NPs).

METHODS

This is a prospective study in BALB/c mice comparing the pharmacokinetics of free drugs with AR NPs. All animals received free drugs or AR NPs (20 mg/kg) in PBS. In vitro replication assays were used for determination of the anti-HIV efficacy of NP formulations. At specific times (free drugs 0.08, 0.125, 0.25, 0.33, 1, 2 and 3 days; AR NPs 0.125, 0.33, 1, 2, 4, 7, 14, 21, 28, 35 and 42 days) mice were euthanized and serum and organs were harvested for determination of AR concentrations by HPLC. Single treatment of monocyte-derived macrophages (MDMs) infected with HIV-1(ada) compared AR NPs (0.005-0.05 mg/mL) with free efavirenz or lopinavir/ritonavir (0.01-0.1 mg/mL), blank NPs and controls. Results are presented as means ± SEM.

RESULTS

Serum free AR drug concentrations peaked 4 h post-injection (ritonavir 3.9 ± 3.05, lopinavir 3.4 ± 2.5 and efavirenz 1.8 ± 0.63 µg/mL) and were eliminated by 72 h. Poly(dl-lactide-co-glycolide) NP animals had detectable ritonavir, lopinavir and efavirenz concentrations in all tissues for 28 days. Treatment of MDMs with AR NPs resulted in sustained inhibition of HIV-1(ada) replication.

CONCLUSIONS

AR drug concentrations from NPs are sustained for 28 days in vivo and anti-HIV inhibition was comparable to that of free drugs in vitro and could be a sustained treatment for delivery of AR drugs.

[AIDS Study Group/Spanish AIDS Plan consensus document on antiretroviral therapy in adults with human immunodeficiency virus infection (updated January 2010)]

OBJECTIVE

This consensus document is an update of antiretroviral therapy recommendations for adult patients with human immunodeficiency virus infection.

METHODS

To formulate these recommendations a panel made up of members of the Grupo de Estudio de Sida (Gesida, AIDS Study Group) and the Plan Nacional sobre el Sida (PNS, Spanish AIDS Plan) reviewed the advances in the current understanding of the pathophysiology of human immunodeficiency virus (HIV) infection, the efficacy and safety of clinical trials, and cohort and pharmacokinetic studies published in biomedical journals or presented at scientific meetings. Three levels of evidence were defined according to the data source: randomized studies (level A), cohort or case-control studies (level B), and expert opinion (level C). The decision to recommend, consider or not to recommend ART was established in each situation.

RESULTS

Currently, the treatment of choice for chronic HIV infection is the combination of three drugs of two different classes, including 2 nucleosides or nucleotide analogs (NRTI) plus 1 non-nucleoside (NNRTI) or 1 boosted protease inhibitor (PI/r), but other combinations are possible. Initiation of ART is recommended in patients with symptomatic HIV infection. In asymptomatic patients, initiation of ART is recommended on the basis of CD4 lymphocyte counts, plasma viral load and patient co-morbidities, as follows: 1) therapy should be started in patients with CD4 counts below 350 cells/microl; 2) When CD4 counts are between 350 and 500 cells/microl, therapy should be started in case of cirrhosis, chronic hepatitis C, high cardiovascular risk, HIV nephropathy, HIV viral load above 100,000 copies/ml, proportion of CD4 cells under 14%, and in people aged over 55; 3) Therapy should be deferred when CD4 are above 500 cells/microl, but could be considered if any of previous considerations concurs. Treatment should be initiated in case of hepatitis B requiring treatment and should be considered for reduce sexual transmission. The objective of ART is to achieve an undetectable viral load. Adherence to therapy plays an essential role in maintaining antiviral response. Therapeutic options are limited after ART failures but undetectable viral loads maybe possible with the new drugs even in highly drug experienced patients. Genotype studies are useful in these situations. Drug toxicity of ART therapy is losing importance as benefits exceed adverse effects. Criteria for antiretroviral treatment in acute infection, pregnancy and post-exposure prophylaxis are mentioned as well as the management of HIV co-infection with hepatitis B or C.

CONCLUSIONS

CD4 cells counts, viral load and patient co-morbidities are the most important reference factors to consider when initiating ART in asymptomatic patients. The large number of available drugs, the increased sensitivity of tests to monitor viral load, and the ability to determine viral resistance is leading to a more individualized therapy approach in order to achieve undetectable viral load under any circumstances.

Evaluation of the pathogenesis of decreasing CD4(+) T cell counts in human immunodeficiency virus type 1-infected patients receiving successfully suppressive antiretroviral therapy

Most human immunodeficiency virus (HIV)-infected individuals experience increases in peripheral CD4(+) T cell counts with suppressive antiretroviral therapy (ART) that achieves plasma HIV RNA levels that are less than the limit of detection. However, some individuals experience decreasing CD4(+) T cell counts despite suppression of plasma viremia. We evaluated 4 patients with a history of CD4(+) T cell decline despite successfully suppressive ART, from a median of 719 cells/mm(3) (range, 360-1141 cells/mm(3)) to 227 cells/mm(3) (range, 174-311 cells/mm(3)) over a period of 18-24 months; 3 of the patients were receiving tenofovir and didanosine, which may have contributed to this decrease. There was no evidence of HIV replication, nor of antiretroviral drug resistance in the blood or lymphoid tissue, or increased proliferation or decreased thymic production of naive CD4(+) T cells. All 4 patients had significant fibrosis of the T cell zone of lymphoid tissue, which appeared to be an important factor in the failure to reconstitute T cells.

Intensification of a suppressive HAART regimen increases CD4 counts and decreases CD8+ T-cell activation

A significant proportion of HIV-1-infected individuals on suppressive HAART regimens do not reconstitute CD4 counts well. If viral reservoirs persist and impact on CD4 reconstitution in a percentage of cases then addition of another antiretroviral agent could further suppress these reservoirs resulting in enhanced CD4 recovery. To evaluate this possibility, we studied the effect of adding abacavir to a chronically suppressive NNRTI containing HAART regimen for 8 patients on their CD4 count and expression of activation markers. Over the first 24 weeks of intensification, CD4 counts increased significantly (p=0.028). This increase continued after a year in follow-up with a significant rate of change in CD4 T-cells of 0.959+/-1.27 per week. In addition, during intensification changes in the percentage of CD38+CD8+ T-cells over time were significantly negatively correlated with changes in CD4 cell number over time above increases predicted without intensification (r(2)=0.716, p=0.008). These data support the possibility that in certain cases where suboptimal CD4 reconstitution occurs that intensification of the regimen can impact immunologic parameters.

Limited long-term naive CD4+ T cell reconstitution in patients experiencing viral load rebounds during HAART

Long-term (3.5 years) immune reconstitution in relation to viral load response was determined. Plasma HIV-1 RNA was suppressed in 40 patients (full responders) up to 42 months, and 17 patients achieved partial response. The measurements of CD4(+) and CD8(+) T lymphocyte subsets (CD45RA, CD45RACD62L, CD45RO, CD28, CD38) were carried out by flow cytometry. Full responders had a significant increase of CD4(+) and all CD4(+) T subsets both up to 6 and from 6 to 42 months, while the increase for partial responders was only up to 6 months. By 6 months, higher slopes were observed in full versus partial responders in the % of CD28 on CD4(+) and the % of CD4(+) memory subset and in both naïve and memory CD4(+) subsets from 6 to 42 months. The percentage of CD8(+) and its subsets was decreased significantly in full responders both up to 6 and from 6 to 42 months (except for an increase in the CD8(+)CD45RA(+) CD62L(+) cells), while in partial responders this decrease was only up to 6 months. Lower slopes were observed in full versus partial responders from 6 to 42 months in the percentages of CD8(+), CD8(+)CD45RO(+), CD8(+)CD28(-), and CD8(+)CD38(+) T cells. In conclusion, full responders have a stronger long-term naive CD4(+) T cell subset reconstitution than partial responders.

Comparison of three kinetic models of HIV-1 infection: implications for optimization of treatment

Clinical markers in the peripheral blood guide the treatment of human immunodeficiency virus type 1 (HIV-1). Likewise, many of the theoretical models developed to simulate infection only incorporate variables in the blood. To test the suitability of blood-only models, three distinct models of HIV infection kinetics are compared: "full model" including latently and actively infected cells and virus in the peripheral blood and lymphoid tissue (LT); "reduced model", including peripheral blood and LT without latent cells; and "blood model" including only actively infected cells and virus in the peripheral blood. Using the same parameter values for all three, qualitative differences are demonstrated between the blood model and its more inclusive counterparts. Additionally, optimization studies show that the reduced and blood models generate progressively lower optimal treatment levels relative to the full model when constant-level treatment is considered. These findings indicate that including the lymphoid tissue and latently infected cells into kinetic models may lead to differing conclusions with regard to optimal treatment and could be useful in guiding therapy even when plasma viral levels are below detectable limits.

Oral and dental care and treatment protocols for the management of HIV-infected patients

This paper describes the workings of the workshop dedicated to oral and dental care and treatment protocols for the management of HIV-infected patients. The questions addressed were: 1) What are the current ethical issues in dental care of HIV patients, do they need to be addressed? 2) Do we need to modify the dental care we give HIV-positive patients? 3) When is it necessary to give antibiotic prophylaxis to HIV-positive patients? 4) What is the evidence for the effective treatment of oral lesions associated with HIV? 5) What is the most successful palliative treatment for KS? 6) Can we provide clinical treatment that has a scientific basis rather being trial based? 7) Is ddI + hydroxy-urea an effective African alternative to HAART? 8) What is the influence of protease inhibitors and HAART on the excretion of HIV in saliva? 9) What is the effect of anti-HIV therapy on the oral mucosa and oral health? This workshop did not fully cover the issue of ddI and hydroxy-urea as an alternative HIV therapy as this was considered to be the remit of general physicians caring for patients with HIV and AIDS rather than that of oral health care workers.

[Recommendations of the Spanish AIDS Study Group (GESIDA) and the National Aids Plan (PNS) for antiretroviral treatment in adult patients with human immunodeficiency virus infection in 2002]

OBJECTIVE

To provide an update of recommendation on antiretroviral treatment (ART) in HIV-infected adults.Methods. These recommendations have been agreed by consensus by a committee of the spanish AIDS Study Group (GESIDA) and the National AIDS Plan. To do so, advances in the physiopathology of AIDS and the results on efficacy and safety in clinical trials, cohort and pharmacokinetics studies published in biomedical journals or presented at congresses in the last few years have been reviewed. Three levels of evidence have been defined according to the data source: randomized studies (level A), case-control or cohort studies (level B) and expert opinion (level C). Whether to recommend, consider, or not to recommend ART has been established for each situation.

RESULTS

Currently, ART with combinations of at least three drugs constitutes the treatment of choice in chronic HIV infection. In patients with symptomatic HIV infection, initiation of ART is recommended. In asymptomatic patients initiation of ART should be based on the CD41/mL lymphocyte count and on the plasma viral load (PVL): a) in patients with CD41 lymphocytes < 200 cells/mL, initiation of ART is recommended; b) in patients with CD41 lymphocytes between 200 and 300 cells/mL, initiation of ART should, in most cases, be recommended; however, it could be delayed when the CD41 lymphocyte count remains close to 350 cells/mL and the PVL is low, and c) in patients with CD41 lymphocytes > 350 cells/mL, initiation of ART can be delayed. The aim of ART is to achieve an undetectable PVL. Adherence to ART plays a role in the durability of the antiviral response. Because of the development of cross-resistance, the therapeutic options in treatment failure are limited. In these cases, genotypic analysis is useful. Toxicity limits ART. The criteria for ART in acute infection, pregnancy and postexposure prophylaxis and in the management of coinfection with HIV and hepatitis C and B virus are controversial.

CONCLUSIONS

The current approach to initiating ART is more conservative than in previous recommendations. In asymptomatic patients, the CD41 lymphocyte count is the most important reference factor for initiating ART. Because of the considerable number of drugs available, more sensitive monitoring methods (PVL) and the possibility of determining resistance, therapeutic strategies have become much more individualized.

Short-cycle structured intermittent treatment of chronic HIV infection with highly active antiretroviral therapy: effects on virologic, immunologic, and toxicity parameters

Although continuous highly active antiretroviral therapy (HAART) is effective for many HIV-infected patients, it can be toxic and prohibitive in cost. By decreasing the total amount of time patients receive medications, intermittent HAART could reduce toxicity and cost. Therefore, we initiated a pilot study in which 10 HIV-infected individuals receiving effective therapy that resulted in levels of HIV RNA <50 copies per ml of plasma and CD4(+) T cell counts >300 cells per mm(3) of whole blood received repeated cycles of 7 days on HAART followed by 7 days off of HAART. Patients maintained suppression of plasma viremia for 32-68 weeks. There was no significant increase in HIV proviral DNA or replication-competent HIV in peripheral CD4(+) T cells or HIV RNA in peripheral blood or lymph node mononuclear cells. There was no significant change in CD4(+) T cell counts, no significant increase in CD4(+) or CD8(+) T cells expressing activation markers or producing IFN-gamma in response to HIV, no increase in CD4(+) T cell proliferation to p24 antigen, and no evidence for the development of resistance to HAART medications. There was a significant decrease in serum cholesterol and triglyceride levels. Thus, in this proof-of-concept study, short-cycle intermittent HAART maintained suppression of plasma viremia as well as HIV replication in reservoir sites while preserving CD4(+) T cell counts. In addition, there was a decrease in serum cholesterol and triglyceride levels. Intermittent therapy may be an important strategy to reduce cost and toxicity for HIV-infected individuals.

CD4 T cell recovery is slower in patients experiencing viral load rebounds during HAART

To determine whether viral load rebounds during HAART impact on CD4+ T cell recovery and immune reconstitution, we studied a prospective cohort of 355 antiretroviral naive patients enrolled to be randomized in a trial of three strategies of induction/maintenance HAART. The extent of immune reconstitution in blood through 72 weeks of antiretroviral treatment was evaluated. Lymphocyte subset markers (CD4, CD8, CD45RA, CD62L, CD16, CD19), activation markers (HLA-DR, CD38, CD25) were performed by cytometry analysis. Our results showed that plasma HIV-1 RNA was suppressed to below 500 copies per ml through week 72 in 240 patients (group 1) while the remaining 115 patients experienced at least one viral rebound (group 2). At baseline, CD4 cell count was higher and HIV-1 RNA was lower in group 1 than in group 2. Over 72 weeks, mean increase in CD4+ T cell count was 0.32 cell/mm3/day in group 1 and only 0.14 cell/mm3/day in group 2 (P < 0.0001). However, the patterns of changes in CD4+ and CD8+ T cell subsets during therapy were very similar across the two groups with only subtle and very limited differences. We conclude that permanent control of HIV replication could be necessary for faster immune reconstitution.

Lymphoid tissue viral burden and duration of viral suppression in plasma

OBJECTIVES

To assess virological response in lymphoid tissue and its impact on the durability of response in plasma in HIV-1-infected persons who achieved sustained suppression of plasma viraemia with different antiretroviral regimens.

METHODS

Consecutive patients on first-line antiretroviral therapy were included if they had a plasma HIV-1 RNA viraemia < 20 copies/ml within the last 6 months and tonsillar tissue accessible for biopsy. First-line therapy contained two nucleoside analogues: alone (2NRTI group, n = 3); plus a HIV-1 protease inhibitor (PI group, n = 11) or plus nevirapine (NVP group; n = 16). Patients were followed until virus was detectable in plasma, they changed therapy or were lost to follow-up.

RESULTS

Tonsillar HIV-1 RNA could be detected (> 100 copies/mg) in 10 patients: one in the PI group (9%), six (38%) in the NVP group and in all three patients in the 2NRTI group. Primary resistance mutations could be detected in only 2 of these 10 patients. After a median of 9 months after the biopsies, viral suppression in plasma had failed in 6 of these 10 patients whereas failure had only occurred in 1 out of 20 with initially undetectable viral load in lymphoid tissue (P = 0.01; log rank test).

CONCLUSIONS

In patients with sustained viral suppression in plasma, triple therapy including a HIV-1 protease inhibitor was more potent than triple therapy containing nevirapine or dual therapy with nucleoside analogues to reduce viral burden in lymphoid tissue. A worse response in lymphoid tissue could not be explained by local selection of resistance and was associated with a less durable virological response in plasma.

Sensitive and reproducible quantitation of mucosal HIV-1 RNA and DNA viral burden in patients with detectable and undetectable plasma viral HIV-1 RNA using endoscopic biopsies

Mucosal tissue is the main portal of entry for HIV-1 infection and, in macaques, has been demonstrated to be a significant compartment for viral replication and CD4+ T lymphocyte depletion. Quantitating tissue viral burden in addition to plasma viral load provides insights into HIV-1 pathogenesis and an additional means to gauge antiretroviral response. The aim of this study was to develop reliable, reproducible, and sensitive assays to quantitate tissue viral burden of HIV-1 RNA and DNA using 1-3 endoscopically acquired, rectosigmoid biopsies. Total DNA and RNA were simultaneously extracted following homogenization from the same tissue samples. Quantitative polymerase chain reaction (PCR) assay in the HIV-1 LTR region was used to detect viral DNA and RT-PCR for viral RNA. It was determined that HIV-1 RNA and DNA can be reproducibly quantified from a single rectosigmoid biopsy with minimal intra-assay or intra-patient variability. These results reflect high recovery of extracted nucleic acids with calculated results accurately reflecting in vivo levels. The techniques outlined differ from currently available approaches by incorporating control standards to identify loss or degradation of RNA and DNA from acquisition through the in vitro assay and permit extraction with high yields of RNA and DNA from the same tissue sample.

International perspectives on antiretroviral resistance. Nonnucleoside reverse transcriptase inhibitor resistance

Although understanding of nonnucleoside reverse transcriptase inhibitor (NNRTI) resistance is less clearly established than that of other classes of antiretroviral drugs, certain facts have been established. The treatment-associated genetic mutation profiles of the available NNRTIs have been mapped, and resistance has been found to develop rapidly after initiation of NNRTI therapy. Despite the chemical diversity of the NNRTIs, cross-resistance among agents of this class is nearly universal. Although the viral replicative capacity ("fitness") of NNRTI-induced viral variants has not been extensively studied, available data suggest that NNRTI-selected mutations confer little damage to viral fitness, and thus a single point mutation produces a strain that is both resistant and fit. Furthermore, with continued therapy, viral evolution persists, creating species with greater numbers of mutations and higher level phenotypic resistance. Taken together, these facts suggest that continued use of NNRTIs after emergence of resistance will produce variants of complex mutational patterns that limit future treatment options, and, therefore, strong consideration should be given to discontinuing NNRTIs after virologic failure is confirmed. This article describes the scientific literature establishing the efficacy and limitations of NNRTI therapy and attempts to define a role for this class of drug in the long-term treatment of HIV-1 disease.

A Randomized Clinical Trial Comparing Nelfinavir Or Nevirapine Associated to Zidovudine/Lamivudine in HIV-Infected Naive Patients (The Combine Study)

Background

Non-nucleoside reverse transcriptase inhibitor-containing regimens may be a valid alternative to protease inhibitor-containing regimens for initial antiretroviral therapy, but to date few studies comparing these two strategies have been performed.

Objective

To evaluate the efficacy and safety of nelfinavir or nevirapine associated to zidovudine/lamivudine in HIV-infected naive patients.

Design

Randomized, open-label, multicentre trial.

Setting

Twelve centres in Spain (9) and Argentina (3).

Patients

One hundred and forty-two HIV-infected naive patients without AIDS.

Interventions

Patients received combivir (zidovudine 300 mg/lamivudine 150 mg, twice-daily) plus either nelfinavir (1250 mg) twice-daily (zidovudine/lamivudine/nelfinavir, n=70) or nevirapine (200 mg) twice-daily (zidovudine/lamivudine/nevirapine, n=72), and were followed for 12 months. The primary endpoint was the proportion of patients with a plasma HIV-1 RNA (pVL) of less than 200 copies/ml by PCR at 12 months. pVL of less than 20 copies/ml (PCR), changes in CD4 counts, clinical progression and adverse events were also evaluated. Efficacy was assessed using intent-to-treat (ITT) (missing=failure) and on-treatment analysis.

Results

At 12 months in the ITT analysis the proportion of patients with pVL below 200 copies/ml was 60% (95% CI 48.5–71.5) in the zidovudine/lamivudine/nelfinavir arm and 75% (95% CI 65–85) in the zidovudine/lamivudine/nevirapine arm ( P=0.06), and the proportion below 20 copies/ml was 50% (95% CI 38.3–61.7) and 65% (95% CI 54.2–76.2), respectively ( P=0.06). No differences were found when comparing the subgroup of patients with baseline pVL of more than 100 000 copies/ml. A gain of +173 and +162 CD4 cells/mm3, respectively, was observed. Zidovudine/lamivudine/nelfinavir was discontinued in 21% of patients, and zidovudine/lamivudine/ nevirapine in 25%, due to toxicity ( P>0.2).

Conclusions

Our results suggest that zidovudine/ lamivudine/nevirapine is at least as effective as zidovudine/lamivudine/nelfinavir as first-line therapy for HIV disease.

Lymph nodes during antiretroviral therapy

Highly active antiretroviral therapy rapidly reduces virus replication in the lymphoid tissue. Production of viral RNA, however, may still be detected in the lymphoid tissue despite negative plasma viremia. Continuing virus production and latent infection in resting cells seem to be important factors for viral rebound following treatment interruption. In parallel with viral suppression, immune activation is decreased and CD4+ T cell counts in the lymphoid tissue increase. It is still not known if there is a potential for complete viral suppression and immune reconstitution. Analyses of the lymphoid tissue during therapy may be helpful in addressing these issues.