Hit HIV-1 hard, but only when necessary

Highly specific SARS-CoV-2 main protease (Mpro) mutations against the clinical antiviral ensitrelvir selected in a safe, VSV-based system

In the SARS-CoV-2 pandemic, the so far two most effective approved antivirals are the protease inhibitors nirmatrelvir, in combination with ritonavir (Paxlovid) and ensitrelvir (Xocova). However, antivirals and indeed all antimicrobial drugs are sooner or later challenged by resistance mutations. Studying such mutations is essential for treatment decisions and pandemic preparedness. At the same time, generating resistant viruses to assess mutants is controversial, especially with pathogens of pandemic potential like SARS-CoV-2. To circumvent gain-of-function research with non-attenuated SARS-CoV-2, a previously developed safe system based on a chimeric vesicular stomatitis virus dependent on the SARS-CoV-2 main protease (VSV-Mpro) was used to select mutations against ensitrelvir. Ensitrelvir is clinically especially relevant due to its single-substance formulation, avoiding drug-drug interactions by the co-formulated CYP3A4 inhibitor ritonavir in Paxlovid. By treating VSV-Mpro with ensitrelvir, highly-specific resistant mutants against this inhibitor were selected, while being still fully or largely susceptible to nirmatrelvir. We then confirmed several ensitrelvir-specific mutants in gold standard enzymatic assays and SARS-CoV-2 replicons. These findings indicate that the two inhibitors can have distinct viral resistance profiles, which could determine treatment decisions.

A combination of nirmatrelvir and ombitasvir boosts inhibition of SARS-CoV-2 replication

Antiviral therapeutics are highly effective countermeasures for the treatment of coronavirus disease 2019 (COVID-19). However, development of resistance to antivirals undermines their effectiveness. Combining multiple antivirals during patient treatment has the potential to overcome the evolutionary selective pressure towards antiviral resistance, as well as provide a more robust and efficacious treatment option. The current evidence for effective antiviral combinations to inhibit severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) replication is limited. Here, we demonstrate a combination of nirmatrelvir with ombitasvir, to jointly bring about potent inhibition of SARS-CoV-2 replication. We developed an in vitro 384- well plate cytopathic effect assay for the evaluation of antiviral combinations against Calu-3 cells infected with SARS-CoV-2 and found, that a combination of ombitasvir and nirmatrelvir was synergistic; thereby decreasing the nirmatrelvir IC50 by approx. 16-fold. The increased potency of the nirmatrelvir-ombitasvir combination, over nirmatrelvir alone afforded a greater than 3 log10 reduction in viral titre, which is sufficient to fully prevent the detection of progeny SARS-CoV-2 viral particles at 48 h post infection. The mechanism of this potentiated effect was shown to be, in-part, due to joint inhibition of the 3-chymotrypsin-like protease via a positive allosteric modulation mechanism.

New Insights into HIV Life Cycle, Th1/Th2 Shift during HIV Infection and Preferential Virus Infection of Th2 Cells: Implications of Early HIV Treatment Initiation and Care

The theory of immune regulation involves a homeostatic balance between T-helper 1 (Th1) and T-helper 2 (Th2) responses. The Th1 and Th2 theories were introduced in 1986 as a result of studies in mice, whereby T-helper cell subsets were found to direct different immune response pathways. Subsequently, this hypothesis was extended to human immunity, with Th1 cells mediating cellular immunity to fight intracellular pathogens, while Th2 cells mediated humoral immunity to fight extracellular pathogens. Several disease conditions were later found to tilt the balance between Th1 and Th2 immune response pathways, including HIV infection, but the exact mechanism for the shift from Th1 to Th2 cells was poorly understood. This review provides new insights into the molecular biology of HIV, wherein the HIV life cycle is discussed in detail. Insights into the possible mechanism for the Th1 to Th2 shift during HIV infection and the preferential infection of Th2 cells during the late symptomatic stage of HIV disease are also discussed.

SARS-CoV-2 3CLpro mutations selected in a VSV-based system confer resistance to nirmatrelvir, ensitrelvir, and GC376

Protease inhibitors are among the most powerful antiviral drugs. Nirmatrelvir is the first protease inhibitor specifically developed against the SARS-CoV-2 protease 3CLpro that has been licensed for clinical use. To identify mutations that confer resistance to this protease inhibitor, we engineered a chimeric vesicular stomatitis virus (VSV) that expressed a polyprotein composed of the VSV glycoprotein (G), the SARS-CoV-2 3CLpro, and the VSV polymerase (L). Viral replication was thus dependent on the autocatalytic processing of this precursor protein by 3CLpro and release of the functional viral proteins G and L, and replication of this chimeric VSV was effectively inhibited by nirmatrelvir. Using this system, we applied nirmatrelvir to select for resistance mutations. Resistance was confirmed by retesting nirmatrelvir against the selected mutations in additional VSV-based systems, in an independently developed cellular system, in a biochemical assay, and in a recombinant SARS-CoV-2 system. We demonstrate that some mutants are cross-resistant to ensitrelvir and GC376, whereas others are less resistant to these compounds. Furthermore, we found that most of these resistance mutations already existed in SARS-CoV-2 sequences that have been deposited in the NCBI and GISAID databases, indicating that these mutations were present in circulating SARS-CoV-2 strains.

Impact of initiation of combination antiretroviral therapy according to the WHO recommendations on the survival of HIV-positive patients in Taiwan

BACKGROUND/PURPOSE

Early initiation of antiretroviral therapy (ART) reduces the risks for serious infections and mortality. We aimed to assess the outcomes of initiating ART among HIV-positive Taiwanese according to the CD4 cut-off values by the WHO recommendations.

METHODS

We reviewed medical records of patients with newly diagnosed HIV infection between 2004 and 2015 and 3 groups of patients were defined according to the timing of ART initiation based on CD4 count recommended by WHO: Group 1 between 2004 and 2009; Group 2 between 2010 and 2012; and Group 3 between 2013 and 2015. The primary outcome was all-cause mortality. All patients were followed until 2 years after the last patient was included in each group.

RESULTS

Of 2022 patients included, the mortality rate was 18.28, 14.01, and 9.10 deaths per 1000 person-years of follow-up (PYFU) in Groups 1, 2, and 3, respectively. In multivariable Cox regression analysis, factors associated with mortality were age (per 1-year increase, adjusted hazard ratio [AHR], 1.06; 95% CI, 1.05-1.08), presence of AIDS-defining disease at HIV diagnosis (AHR, 4.81; 95% CI, 2.99-7.74), solid-organ malignancy (AHR, 3.10; 95% CI, 1.86-5.18), and initiation of ART (AHR, 0.09; 95% CI, 0.05-0.16). By competing risk regression model for non-AIDS-related death, the AHR for Group 3 versus Group 1 was 0.27 (95% CI, 0.09-0.80).

CONCLUSIONS

While continued efforts are needed to improve early diagnosis and linkage to care, initiation of cART improved survival among HIV-positive patients in Taiwan according to the increasing CD4 cut-off values that were recommended by the WHO.

Linkage to HIV care and its determinants in the late HAART era: a systematic review and meta-analysis

Poor engagement into HIV care limits the effectiveness of highly active antiretroviral therapies (HAART) to improve survival and reduce transmission. The design of effective interventions to enhance linkage to care is dependent on evidence about rates of entry into HIV care. This is a systematic review and meta-analysis on linkage measurement and its determinants in the late era of HAART (post-2003), in high-income countries. We searched the PubMed and Web of Science databases, restricting our sample to the late HAART era (post-2003) until February 2016, and to high-income countries. We retained only studies that produced quantified outcomes. We rejected the studies with a high risk of bias, and followed a standard meta-analytic approach. Because there was a high heterogeneity ( I ² > 90%), the aggregated findings were based on a random-effects model. A total of 43 studies were identified, all of them following a cohort of patients newly diagnosed until referred to specialized care. For a one-month period, the meta-proportion was 71.1% (IC95%: 61.0%-81.2). For a three-month duration, the meta-proportion of linkage to care was 77.0% (IC95%: 75.0%-79.0). For a one-year period, the meta-proportion was 76.3% (IC95%: 54.2%-98.4%). The proportions were lower when lab tests were used as referral indicator, with a pooled meta-proportion of 76.7% (IC95%: 73.0%-80.4), in comparison to a value of 80.8% (IC95%: 68.7%-92.9) for consultations. Being black or male were the most commonly observed determinants of delayed entry into care. Young people, injecting drug users, people with low socioeconomic status, or at a less advanced stage of disease also experienced lower proportions of timely linkage. Timely engagement into care is below 80% and specific sub-groups are particularly at risk of late entry. These findings confirm earlier evidence that linkage to care remains low, and that efforts should focus on vulnerable populations.

When to start antiretroviral treatment? A history and analysis of a scientific controversy

Background

Since 1987 HIV scientists and activists have debated the optimal point to start antiretroviral treatment. Positions have varied between treating people with HIV as soon as they are diagnosed, based on biological, modelling and observational evidence, versus delaying treatment until points in disease progression at which clinical trial evidence has shown unequivocally that treatment is beneficial.

Objectives

Examining the conduct and resolution of this debate may provide insight into how science works in practice. It also documents an important part of the history of the HIV epidemic.

Method

We describe clinical trials, observational studies, models and various documents that have advanced the debate from 1987 to 2015.

Results and conclusion

Evidence accumulated over the past decade, especially from randomised controlled clinical trials, has shown that immediate treatment both reduces the mortality and the risk of HIV transmission; it benefits both public health and the individual patient. By mid-2015, the debate was resolved in favour of immediate treatment.

Impact of Human Immunodeficiency Virus in the Pathogenesis and Outcome of Patients with Glioblastoma Multiforme

Background

Improvement in antiviral therapies have been accompanied by an increased frequency of non-Acquired Immune Deficiency Syndrome (AIDS) defining malignancies, such as glioblastoma multiforme. Here, we investigated all reported cases of human immunodeficiency virus (HIV)-positive patients with glioblastoma and evaluated their clinical outcomes. A comprehensive review of the molecular pathogenetic mechanisms underlying glioblastoma development in the setting of HIV/AIDS is provided.

Methods

We performed a PubMed search using keywords “HIV glioma” AND “glioblastoma,” and “AIDS glioma” AND “glioblastoma.” Case reports and series describing HIV-positive patients with glioblastoma (histologically-proven World Health Organization grade IV astrocytoma) and reporting on HAART treatment status, clinical follow-up, and overall survival (OS), were included for the purposes of quantitative synthesis. Patients without clinical follow-up data or OS were excluded. Remaining articles were assessed for data extraction eligibility.

Results

A total of 17 patients met our inclusion criteria. Of these patients, 14 (82.4%) were male and 3 (17.6%) were female, with a mean age of 39.5±9.2 years (range 19–60 years). Average CD4 count at diagnosis of glioblastoma was 358.9±193.4 cells/mm³. Tumor progression rather than AIDS-associated complications dictated patient survival. There was a trend towards increased median survival with HAART treatment (12.0 vs 7.5 months, p=0.10)

Conclusion

Our data suggests that HAART is associated with improved survival in patients with HIV-associated glioblastoma, although the precise mechanisms underlying this improvement remain unclear.

Progression to AIDS slowed even more after the first two years with highly active antiretroviral therapy

Aims: The aim of this study was to describe the effectiveness of highly active antiretroviral treatment for HIV after the treatment became publicly available in Norway in August 1996 and through to the year 2000. The effectiveness was studied for the three main transmission groups for HIV in Norway. Methods: Effectiveness was measured as change in progression to AIDS after highly active antiretroviral treatment for HIV was introduced in the population of HIV-diagnosed persons. Notifications of HIV diagnosed persons and persons with AIDS from 1983 to 2000 in Norway were used in the analysis. Progression to AIDS after August 1996 compared with progression to AIDS before 1996 was analysed by Kaplan-Meier curves and Cox regression models. Results: Progression to AIDS slowed after highly active antiretroviral treatment was introduced. The intensity of getting AIDS was significantly reduced after August 1996 compared with the intensity of getting AIDS before August 1996. The reduction in intensity after August 1996 was less explicit in the two years following August 1996 than in the subsequent two and a half years from August 1998 to December 2000. The reduction was less explicit among HIV-diagnosed intravenous drug users. Conclusions: The effectiveness of highly active antiretroviral treatment lasted for at least four and a half years and increased after the first two calendar years. The problem of less effectiveness among HIV-diagnosed intravenous drug users should be addressed by the health authorities.

Past, Present, and Future of Traumatic Brain Injury Research

Traumatic brain injury (TBI) is the greatest cause of death and severe disability in young adults; its incidence is increasing in the elderly and in the developing world. Outcome from severe TBI has improved dramatically as a result of advancements in trauma systems and supportive critical care, however we remain without a therapeutic which acts directly to attenuate brain injury. Recognition of secondary injury and its molecular mediators has raised hopes for such targeted treatments. Unfortunately, over 30 late-phase clinical trials investigating promising agents have failed to translate a therapeutic for clinical use. Numerous explanations for this failure have been postulated and are reviewed here. With this historical context we review ongoing research and anticipated future trends which are armed with lessons from past trials, new scientific advances, as well as improved research infrastructure and funding. There is great hope that these new efforts will finally lead to an effective therapeutic for TBI as well as better clinical management strategies.

A piecewise model of virus-immune system with two thresholds

The combined antiretroviral therapy with interleukin (IL)-2 treatment may not be enough to preclude exceptionally high growth of HIV virus nor rebuilt the HIV-specific CD4 or CD8 T-cell proliferative immune response for management of HIV infected patients. Whether extra inclusion of immune therapy can induce the HIV-specific immune response and control HIV replication remains challenging. Here a piecewise virus-immune model with two thresholds is proposed to represent the HIV-1 RNA and effector cell-guided therapy strategies. We first analyze the dynamics of the virus-immune system with effector cell-guided immune therapy only and prove that there exists a critical level of the intensity of immune therapy determining whether the HIV-1 RAN virus loads can be controlled below a relative low level. Our analysis of the global dynamics of the proposed model shows that the pseudo-equilibrium can be globally stable or locally bistable with order 1 periodic solution or bistable with the virus-free periodic solution under various appropriate conditions. This indicates that HIV viral loads can either be eradicated or stabilize at a previously given level or go to infinity (corresponding to the effector cells oscillating), depending on the threshold levels and the initial HIV virus loads and effector cell counts. Comparing with the single threshold therapy strategy we obtain that with two thresholds therapy strategies either virus can be eradicated or the controllable region, where HIV viral loads can be maintained below a certain value, can be enlarged.

Piecewise virus-immune dynamic model with HIV-1 RNA-guided therapy

Clinical studies have used CD4 T cell counts to evaluate the safety or risk of plasma HIV-1 RNA-guided structured treatment interruptions (STIs), aimed at maintaining CD4 T cell counts above a safe level and plasma HIV-1 RNA below a certain level. However, quantifying and evaluating the impact of STIs on the control of HIV replication and on activation of the immune response remains challenging. Here we extend the virus-immune dynamic system by including a piecewise smooth function to describe the elimination of HIV viral loads and the activation of effector cells under plasma HIV-1 RNA-guided therapy, in order to quantitatively explore the STI strategies. We theoretically investigate the global dynamics of the proposed Filippov system. Our main results indicate that HIV viral loads could either go to infinity or be maintained below a certain level or stabilize at a previously given level, depending on the threshold level and initial HIV virus loads and effector cell counts. This suggests that proper combinations of threshold and initial HIV virus loads and effector cell counts, based on threshold policy, can successfully preclude exceptionally high growth of HIV virus and, in particular, maximize the controllable region.

HIV patients' decision of switching to second-line antiretroviral therapy in India

The objective is to examine when patients should switch to second-line antiretroviral therapy (ART) under health uncertainty and in the absence of viral load monitoring. We formalize and solve the therapeutic dilemma about whether or not, and when, to switch a therapy. The model's main value-added consists in the concrete application to patients with HIV in India. In our dynamic stochastic model, health level volatility can be understood as the variation in CD4 count and the trend of health level as increases in CD4 count and, thus, decreases in the incidence of opportunistic infections and mortality. The results of the empirical application suggest that the theoretical model can explain ART treatment switch. Treatment switch depends negatively on the volatility of patients' health, and on trend of health, i.e., the greater the variation in CD4 count and the more CD4 count increase, the fewer treatment switches one expects to occur. Treatment switch also depends negatively on the degree of irreversibility. Under irreversibility, low-risk patients must begin the second-line treatment as soon as possible, which is precisely when the second-line treatment is least valuable. The existence of an option value means that ART first-line regimen may be the better choice when considering lifetime welfare. Conversely, treatment switch depends positively on the discount rate and on the correlation between the patient's health under first- and second-line treatments. This means that treatment switch is likelier to succeed in second-line treatments that are similar to the first-line treatments, implying that a decision-maker should not rely on treatment switch as a risk diversification tool.

Design of acute neuroprotection studies

Traumatic brain injury (TBI) is a substantial public health problem. The discovery of progressive, ongoing damage to the brain by means of complex molecular mechanisms which follow the initial injury has raised the possibility of targeted therapeutic intervention. Despite a substantial investment in trials testing dozens of therapeutics in humans, however, to date none has demonstrated robust efficacy. Deficiencies in the design of human clinical trials is likely to explain many translational failures, at least in part. Here we review secondary injury mediators and key trials which have targeted them. We provide a thorough discussion of putative reasons why trials thus far have failed and suggestions for the design of future clinical studies. Important insights from the IMPACT study are also presented in detail; in addition to providing critical insights for future trial design and analysis it suggests that reanalysis of completed studies may reveal inappropriately discarded treatments. Unfortunately limited resources are available for translational research and it is difficult to procure funds needed for well-resourced, large and definitive studies. History suggests, however, that investing in studies that are unlikely to provide a definitive answer only serves to increase required investment as they tend to mandate further study.

Should expectations about the rate of new antiretroviral drug development impact the timing of HIV treatment initiation and expectations about treatment benefits?

Background

Many analyses of HIV treatment decisions assume a fixed formulary of HIV drugs. However, new drugs are approved nearly twice a year, and the rate of availability of new drugs may affect treatment decisions, particularly when to initiate antiretroviral therapy (ART).

Objectives

To determine the impact of considering the availability of new drugs on the optimal initiation criteria for ART and outcomes in patients with HIV/AIDS.

Methods

We enhanced a previously described simulation model of the optimal time to initiate ART to incorporate the rate of availability of new antiviral drugs. We assumed that the future rate of availability of new drugs would be similar to the past rate of availability of new drugs, and we estimated the past rate by fitting a statistical model to actual HIV drug approval data from 1982–2010. We then tested whether or not the future availability of new drugs affected the model-predicted optimal time to initiate ART based on clinical outcomes, considering treatment initiation thresholds of 200, 350, and 500 cells/mm³. We also quantified the impact of the future availability of new drugs on life expectancy (LE) and quality-adjusted life expectancy (QALE).

Results

In base case analysis, considering the availability of new drugs raised the optimal starting CD4 threshold for most patients to 500 cells/mm³. The predicted gains in outcomes due to availability of pipeline drugs were generally small (less than 1%), but for young patients with a high viral load could add as much as a 4.9% (1.73 years) increase in LE and a 8% (2.43 QALY) increase in QALE, because these patients were particularly likely to exhaust currently available ART regimens before they died. In sensitivity analysis, increasing the rate of availability of new drugs did not substantially alter the results. Lowering the toxicity of future ART drugs had greater potential to increase benefit for many patient groups, increasing QALE by as much as 10%.

Conclusions

The future availability of new ART drugs without lower toxicity raises optimal treatment initiation for most patients, and improves clinical outcomes, especially for younger patients with higher viral loads. Reductions in toxicity of future ART drugs could impact optimal treatment initiation and improve clinical outcomes for all HIV patients.

The timing and probability of treatment switch under cost uncertainty: an application to patients with gastrointestinal stromal tumor

BACKGROUND

Cost fluctuations render the outcome of any treatment switch uncertain, so that decision makers might have to wait for more information before optimally switching treatments, especially when the incremental cost per quality-adjusted life year (QALY) gained cannot be fully recovered later on.

OBJECTIVE

To analyze the timing of treatment switch under cost uncertainty.

METHODS

A dynamic stochastic model for the optimal timing of a treatment switch is developed and applied to a problem in medical decision taking, i.e. to patients with unresectable gastrointestinal stromal tumour (GIST).

RESULTS

The theoretical model suggests that cost uncertainty reduces expected net benefit. In addition, cost volatility discourages switching treatments. The stochastic model also illustrates that as technologies become less cost competitive, the cost uncertainty becomes more dominant. With limited substitutability, higher quality of technologies will increase the demand for those technologies disregarding the cost uncertainty. The results of the empirical application suggest that the first-line treatment may be the better choice when considering lifetime welfare.

CONCLUSIONS

Under uncertainty and irreversibility, low-risk patients must begin the second-line treatment as soon as possible, which is precisely when the second-line treatment is least valuable. As the costs of reversing current treatment impacts fall, it becomes more feasible to provide the option-preserving treatment to these low-risk individuals later on.

The detection and management of early HIV infection: a clinical and public health emergency

This review considers the detection and management of early HIV infection (EHI), defined here as the first 6 months of infection. This phase is clinically important because a reservoir of infected cells formed in the individual renders HIV incurable, and the magnitude of viremia at the end of this period predicts the natural history of disease. Epidemiologically, it is critical because the very high viral load that typically accompanies early infection also makes infected individuals maximally contagious to their sexual partners. Future efforts to prevent HIV transmission with expanded testing and treatment may be compromised by elevated transmission risk earlier in the course of HIV infection, although the extent of this impact is yet unknown. Treatment as prevention efforts will nevertheless need to develop strategies to address testing, linkage to care, and treatment of EHI. Cost-effective and efficient identification of more persons with early HIV will depend on advancements in diagnostic technology and strengthened symptom-based screening strategies. Treatment for persons with EHI must balance individual health benefits and reduction of the risk of onward viral transmission. An increasing body of evidence supports the use of immediate antiretroviral therapy to treat EHI to maintain CD4 count and functionality, limit the size of the HIV reservoir, and reduce the risk of onward viral transmission. Although we can anticipate considerable challenges in identifying and linking to care persons in the earliest phases of HIV infection, there are many reasons to pursue this strategy.

Candidate antibody-based therapeutics against HIV-1

Antibody-based therapeutics have been successfully used for the treatment of various diseases and as research tools. Several well characterized, broadly neutralizing monoclonal antibodies (bnmAbs) targeting HIV-1 envelope glycoproteins or related host cell surface proteins show sterilizing protection of animals, but they are not effective when used for therapy of an established infection in humans. Recently, a number of novel bnmAbs, engineered antibody domains (eAds), and multifunctional fusion proteins have been reported which exhibit exceptionally potent and broad neutralizing activity against a wide range of HIV-1 isolates from diverse genetic subtypes. eAds could be more effective in vivo than conventional full-size antibodies generated by the human immune system. Because of their small size (12∼15 kD), they can better access sterically restricted epitopes and penetrate densely packed tissue where HIV-1 replicates than the larger full-size antibodies. HIV-1 possesses a number of mechanisms to escape neutralization by full-size antibodies but could be less likely to develop resistance to eAds. Here, we review the in vitro and in vivo antiviral efficacies of existing HIV-1 bnmAbs, summarize the development of eAds and multispecific fusion proteins as novel types of HIV-1 inhibitors, and discuss possible strategies to generate more potent antibody-based candidate therapeutics against HIV-1, including some that could be used to eradicate the virus.

Balancing immunological benefits and cardiovascular risks of antiretroviral therapy: when is immediate treatment optimal?

We developed a mathematical model to identify the timing of antiretroviral therapy (ART) initiation that optimizes patient outcomes as a function of patient CD4 count, age, cardiac mortality risk, sex, and personal preferences. Our goal was to find the conditions that maximize patient quality-adjusted life expectancy (QALE) in the context of our model. Under the assumption that ART confers disease progression and mortality benefits at any CD4 count, immediate treatment initiation yields the greatest remaining QALE for young patients under most circumstances. The timing of ART initiation depends on the magnitude of benefit from ART at high CD4 counts, the magnitude of increases in cardiac risk, and patients' preferences. If ART reduces HIV progression at high CD4 counts, immediate ART is preferable for most newly infected individuals <35 years even if ART doubles age- and sex-specific cardiac risk.

Low dose adrenocorticotropic hormone test and adrenal insufficiency in critically ill acquired immunodeficiency syndrome patients

CONTEXT

Prevalence of adrenal insufficiency (AI) is not uncommon in HIV infected population. However, AI is rarely diagnosed in clinical practice because many patients have non-specific symptoms and signs. Critical illness in such patients further complicates the evaluation of adrenal function. A 1μgm ACTH test can be used for diagnosis, since it results in more physiological levels of ACTH. A serum cortisol of <18 μg/dL, 30 or 60-minutes after ACTH test has been accepted as indicative of AI, but many experts advocate the normal cortisol response should exceed 25 μg/dL, in critically ill patients.

AIM

To determine the prevalence of AI in critically ill AIDS patients, by using 1 μg ACTH test and also, to compare the diagnostic criteria for adrenal insufficiency between cortisol response of <18 μg/dL and <25 μg/dL.

SETTINGS AND DESIGN

This prospective study was done in the Department of Medicine.

MATERIALS AND METHODS

After taking blood for basal plasma cortisol from AIDS affected fifty adult men and women aged over 18 yrs, 1 μg ACTH was given intravenously, and blood samples were again collected at 30 and 60 minutes for plasma cortisol estimation.

STATISTICAL ANALYSIS

It was done by Mann-Whitney test.

RESULTS

Prevalence of AI was 74% (37 patients) and 92% (46 patients), when the peak stimulated cortisol level of <18 μg/dL and <25 μg/dL, respectively, was used.

CONCLUSION

AI is more prevalent in critically ill AIDS patients. Hence, this test can be performed for early intervention and better management.

Considerations in the rationale, design and methods of the Strategic Timing of AntiRetroviral Treatment (START) study

BACKGROUND

Untreated human immunodeficiency virus (HIV) infection is characterized by progressive depletion of CD4+ T lymphocyte (CD4) count leading to the development of opportunistic diseases (acquired immunodeficiency syndrome (AIDS)), and more recent data suggest that HIV is also associated with an increased risk of serious non-AIDS (SNA) diseases including cardiovascular, renal, and liver diseases and non-AIDS-defining cancers. Although combination antiretroviral treatment (ART) has resulted in a substantial decrease in morbidity and mortality in persons with HIV infection, viral eradication is not feasible with currently available drugs. The optimal time to start ART for asymptomatic HIV infection is controversial and remains one of the key unanswered questions in the clinical management of HIV-infected individuals.

PURPOSE

In this article, we outline the rationale and methods of the Strategic Timing of AntiRetroviral Treatment (START) study, an ongoing multicenter international trial designed to assess the risks and benefits of initiating ART earlier than is currently practiced. We also describe some of the challenges encountered in the design and implementation of the study and how these challenges were addressed.

METHODS

A total of 4000 study participants who are HIV type 1 (HIV-1) infected, ART naïve with CD4 count > 500 cells/µL are to be randomly allocated in a 1:1 ratio to start ART immediately (early ART) or defer treatment until CD4 count is <350 cells/µL (deferred ART) and followed for a minimum of 3 years. The primary outcome is time to AIDS, SNA, or death. The study had a pilot phase to establish feasibility of accrual, which was set as the enrollment of at least 900 participants in the first year.

RESULTS

Challenges encountered in the design and implementation of the study included the limited amount of data on the risk of a major component of the primary endpoint (SNA) in the study population, changes in treatment guidelines when the pilot phase was well underway, and the complexities of conducting the trial in a geographically wide population with diverse regulatory requirements. With the successful completion of the pilot phase, more than 1000 participants from 100 sites in 23 countries have been enrolled. The study will expand to include 237 sites in 36 countries to reach the target accrual of 4000 participants.

CONCLUSIONS

START is addressing one of the most important questions in the clinical management of ART. The randomization provided a platform for the conduct of several substudies aimed at increasing our understanding of HIV disease and the effects of antiretroviral therapy beyond the primary question of the trial. The lessons learned from its design and implementation will hopefully be of use to future publicly funded international trials.

Predictors of CD4 eligibility for antiretroviral therapy initiation among HIV-infected pregnant women in Lusaka, Zambia

BACKGROUND

In resource-limited settings, CD4 testing is a barrier to antiretroviral therapy initiation in pregnancy.

METHODS

We used logistic regression to identify predictors of CD4 cell count ≤ 350 cells/uL in 20,233 pregnant women.

RESULTS

The best-performing model included any 3 of: age ≥ 28 years old, hemoglobin ≤ 9.8 g/dL, gestational age ≤ 30 weeks, weight ≤ 64 kg, history of tuberculosis or previous death of an infant prior to one year old. Sensitivity was 45.7% (95% CI: 44.5-47.0), specificity 70.7% (95% CI: 69.6-71.8), and misclassification rate 41.4% (95% CI: 40.5-42.2).

CONCLUSION

CD4 triage remains a critical element of maternal HIV care and PMTCT.

Clinical manifestations of treatment-naive patients with acquired immunodeficiency syndrome and responses to highly active antiretroviral therapy in the Taipei Veterans General Hospital: a 5-year prospective study

BACKGROUND

Taipei Veterans General Hospital, one of the medical centers in Taiwan, has provided highly active antiretroviral therapy (HAART) to human immunodeficiency virus/AIDS patients for more than 10 years. Five years ago, we began a prospective follow-up of our patients' clinical manifestations and responses to HAART by collecting their clinical data. In this study, we analyzed the morbidity, mortality, and responses to HAART of treatment-naive AIDS patients. The purpose was to provide local data that may be valuable in Taiwan.

METHODS

Study cases were enrolled from January 1, 2004, to February 28, 2009, with inclusion criteria of newly diagnosed AIDS during hospitalization and being naive to HAART. Antiretroviral therapy was initiated. To evaluate the clinical responses to HAART, we excluded patients who were pregnant, died within 1 month after confirmation of an AIDS diagnosis, failed to initiate HAART, or were lost to follow-up for more than 6 months. Plasma viral loads and CD4(+) counts were quantified by reverse-transcriptase polymerase chain reaction and flow cytometry, respectively. Statistical analysis was performed using SPSS statistical software.

RESULTS

A total of 49 patients were enrolled and 45 patients fulfilled the inclusion criteria for evaluating the efficacy of HAART. At 3 months, 12 months, and 30 months after the initiation of HAART, 64.4% (29 of 45), 88.2% (30 of 34), and 93.8% (15 of 16) had undetectable plasma viral loads, respectively, and 37.8% (17 of 45), 73.5% (25 of 34), and 81.2% (13 of 16) had CD4(+) counts of more than 200 cells/μL, respectively. Median CD4(+) counts increased from baseline at Month 3 by 171 cells/μL and at Month 30 by 375 cells/μL. The overall mortality was 22.4% (11 of 49).

CONCLUSION

The virologic and immunologic responses after initiating HAART in this study demonstrated our achievements in providing care and treatment for AIDS patients during this 5-year period, which provides a strong evidence of the efficacy of HAART.

How HIV treatment could result in effective prevention

As the number of HIV infections continues to surpass treatment capacity, new HIV prevention strategies are imperative. Beyond individual clinical benefits, by rendering an individual less infectious, expanding access to highly active antiretroviral therapy (HAART) could also have a larger public health impact of curbing new HIV infections. Recent guidelines have moved towards initiating HAART at higher CD4 cell counts, thus increasing the number of individuals in need of treatment. A new treatment strategy is wanting that can simultaneously curb the epidemic and provide necessary treatment to those most in need. A recent debate has centered on whether an expansion of free and universal treatment, regardless of CD4 cell count, could be a means of HIV prevention. In light of the growing access to HAART in resource-limited settings and increasing evidence suggesting the clinical and prevention benefits of initiating treatment at higher CD4 cell counts, it is conceivable that, in the future, HAART will be an integral part of both individual-level clinical treatment programs as well as public health-based HIV prevention interventions.

Pharmacoeconomic evaluation of intensified antiretroviral treatment strategies in HIV/AIDS

There have been great technological advances in the use of antiretroviral therapies to slow down disease progression in HIV/AIDS. Combinations of therapeutics and the use of several diagnostic methods have resulted in both declines in mortality and the occurrence of opportunistic infections. The higher costs of these therapeutics have prompted questions about the economic aspects of treatment with antiretrovirals. In this review, we provide an overview of the research that has been published on this topic and list the important outcomes and methodological issues associated with the different therapies.

Postpartum discontinuation of antiretroviral therapy and risk of maternal AIDS-defining events, non-AIDS-defining events, and mortality among a cohort of HIV-1-infected women in the United States

This retrospective cohort study of HIV-infected women receiving highly active antiretroviral therapy (HAART) while pregnant assessed the effect of postpartum HAART discontinuation on maternal AIDS-defining events (ADEs), non-AIDS-defining events (non-ADEs), and death 1997-2008 in Nashville, Tennessee. Cox proportional hazards models compared rates of ADE or all-cause death and non-ADE or all-cause death, and competing risks analyses compared rates of ADE or ADE-related death and non-ADE or non-ADE-related death across the groups. There were two groups: women who stopped HAART postpartum (discontinuation, n = 54) and women who continued HAART postpartum (continuation, n = 69). Fifty percent were African American, 40% had prior non-HAART antiretroviral therapy (ART) use, and 38% had a history of illicit drug use. Median age was 27.5 years, baseline CD4(%) was 532 (34%) and CD4 nadir was 332 cells/mm(3), baseline and peak HIV-1 RNA were 2.6 and 4.32 log(10) copies per milliliter, respectively. Women in the continuation group were older, had lower baseline CD4, CD4%, and CD4 nadir, and had higher peak HIV-1 RNA. In multivariable proportional hazards models, the hazard ratios [95% confidence interval (CI)] of ADE or all-cause death and non-ADE or all-cause death were lower in the continuation group, but not statistically significantly: 0.50 (0.12, 2.12; p = 0.35) and 0.69 (0.24, 1.95; p = 0.48), respectively. The results were similar in competing risks analyses. Despite having characteristics associated with worse prognosis, women who continued HAART postpartum had lower hazard ratio point estimates for ADEs or death and non-ADEs or death than women who discontinued HAART. Larger studies with longer follow-up are indicated to assess this association.

Medical technology adoption, uncertainty, and irreversibilities: is a bird in the hand really worth more than in the bush?

The influence of current medical technology adoption decisions on the use of future potential interventions is often overlooked. Some health interventions, once exercised, restrict future potential interventions for both related and unrelated medical conditions. For example, treatment of a patient with an antibiotic may lead to resistance in that patient that precludes future treatment with the same or related compounds. This irreversibility raises the value of treatment modalities that preserve future treatment options. Surprisingly, partial reversibility with or without learning can either increase or decrease this value, depending on the distribution of patient types within the treated population. Evaluations that ignore these option values miss an important part of the welfare equation that is becoming increasingly important as individuals live longer and the stock of medical treatments increases.

Early treatment of HIV: implications for resource-limited settings

PURPOSE OF REVIEW

We review the current literature supporting adoption of higher CD4 thresholds for initiation of antiretroviral treatment and survey progress in adoption of early treatment policies in resource-limited settings. We highlight some of the challenges and opportunities implementation of early treatment will bring.

RECENT FINDINGS

The initial success of combination antiretroviral treatment resulted in the recommendation to treat early all individuals with HIV. However, the gradual realization that antiretroviral treatment was associated with toxicity led to a more tempered approach. Recent cohort studies and some clinical trials have shown that delaying treatment is associated with increased morbidity and mortality.

SUMMARY

Early treatment is routinely practiced in developed countries. Now, early treatment is being adopted as a strategy in many resource-limited settings. The implications of this policy shift are not known, but we predict early treatment will have important consequences for the health system, the individual, and the community. Whereas these consequences will bring significant challenges, the increased numbers of HIV-infected individuals on treatment will result in many new opportunities - antiretroviral treatment will become less expensive, systems to deliver chronic care will be strengthened, and the policy shift will focus greater attention on pregnant women and children. Finally, some authors postulate that early treatment may impact HIV transmission.

Combination therapies for traumatic brain injury: prospective considerations

Traumatic brain injury (TBI) initiates a cascade of numerous pathophysiological events that evolve over time.Despite the complexity of TBI, research aimed at therapy development has almost exclusively focused on single therapies, all of which have failed in multicenter clinical trials. Therefore, in February 2008 the National Institute of Neurological Disorders and Stroke, with support from the National Institute of Child Health and Development, the National Heart, Lung, and Blood Institute, and the Department of Veterans Affairs, convened a workshop to discuss the opportunities and challenges of testing combination therapies for TBI. Workshop participants included clinicians and scientists from a variety of disciplines, institutions, and agencies. The objectives of the workshop were to: (1) identify the most promising combinations of therapies for TBI; (2) identify challenges of testing combination therapies in clinical and pre-clinical studies; and (3) propose research methodologies and study designs to overcome these challenges. Several promising combination therapies were discussed, but no one combination was identified as being the most promising. Rather, the general recommendation was to combine agents with complementary targets and effects (e.g., mechanisms and time-points), rather than focusing on a single target with multiple agents. In addition, it was recommended that clinical management guidelines be carefully considered when designing pre-clinical studies for therapeutic development.To overcome the challenges of testing combination therapies it was recommended that statisticians and the U.S. Food and Drug Administration be included in early discussions of experimental design. Furthermore, it was agreed that an efficient and validated screening platform for candidate therapeutics, sensitive and clinically relevant biomarkers and outcome measures, and standardization and data sharing across centers would greatly facilitate the development of successful combination therapies for TBI. Overall there was great enthusiasm for working collaboratively to act on these recommendations.

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.

Antiretroviral therapy interruption guided by CD4 cell counts and plasma HIV-1 RNA levels in chronically HIV-1-infected patients

OBJECTIVE

We evaluated the safety of CD4 cell count and plasma HIV-1 RNA (pVL)-guided treatment interruptions (GTI) and determined predictors of duration of treatment interruption.

METHODS

Chronically HIV-1-infected adults with sustained CD4 cell counts > 500 cells/microl and pVL < 50 copies/ml were randomly assigned to either continue with standard antiretroviral therapy (control group, n = 101) or to interrupt therapy aimed at maintaining CD4 cell counts > 350 cells/microl and pVL < 100,000 copies/ml (GTI group, n = 100). Both groups were followed for 2 years.

RESULTS

There were no AIDS-defining illnesses or deaths in either group. Compared to controls, subjects interrupting therapy reduced treatment exposure by 67%, but suffered significantly more adverse events related to the intake of medication or to therapy interruption [relative hazard, 2.71; 95% confidence interval (CI), 1.64-4.49; P < 0.001), mainly due to an excess in mononucleosis-like symptoms. While GTI subjects demonstrated improvements in the psychosocial spheres of quality of life and pain reporting, GTI had no effect on the physical aspects of quality of life. Although both groups had a similar hazard for developing CD4 cell count < 200 cells/microl; at least 10% of subjects on GTI had CD4 cell counts < 350 cells/microl at every time point. Drug resistance mutations were detected in 36% of subjects but were selected de novo only in subjects interrupting non-nucleoside reverse transcriptase inhibitor therapy. Lower CD4 cell count nadir, higher set-point pVL and prior exposure to suboptimal regimens were all independent predictors of the need to reinitiate treatment.

CONCLUSIONS

Overall, GTI were not as safe as continuing therapy. Despite achieving some improvements in quality of life, GTI did not reduce the overall rate of management-related adverse events.

[Antiviral treatment regimens]

The availability and use of effective antiretroviral combination therapies has dramatically decreased the morbidity and mortality of HIV infection. Almost complete suppression of viral replication by antiretroviral therapy prevents disease progression and development of resistance, as well as leading to both regression of HIV-associated symptoms and clinically relevant immune reconstitution. More than 20 antiretroviral substances in four classes have been approved. As a result of the broad therapeutic options, HIV infection can be better treated. Although a high number of combinations can be conceived, only a small number is actually applicable. The decisions to start, monitor and change therapy have become even more difficult. The indication for treatment, the selection of the most suitable therapy for an individual, the counseling of the patient, and the monitoring of the success of treatment demand a high level of knowledge and experience. Virologic failures of modern antiretroviral therapy regimens are rare in adherent patients.

Patients' readiness to start highly active antiretroviral treatment for HIV

Assessing whether patients are ready to start antiretroviral treatment may improve HIV prevention and treatment outcomes

Effect of efavirenz treatment on the pharmacokinetics of nelfinavir boosted by ritonavir in healthy volunteers

AIMS

A once-daily (q.d.) nucleoside-sparing regimen can prevent mitochondrial toxicity, overcome viral resistance and improve compliance. In the present study the effect of efavirenz on the pharmacokinetics and tolerability of once-daily nelfinavir/ritonavir was evaluated in healthy subjects.

METHODS

This was a multiple-dose, open-label, single-group, two-period study in 24 healthy subjects. Each received from days 1-10 (period 1): 1875 mg nelfinavir plus 200 mg ritonavir q.d. with a 300-kcal snack. During days 11-20 (period 2) efavirenz 600 mg q.d. was added to the regimen. Blood samples were collected up to 24 h after dosing on days 10 (period 1) and 20 (period 2). High-performance liquid chromatography methods were used for the determination of the concentrations of all compounds. The main pharmacokinetic parameters were calculated using noncompartmental methods.

RESULTS

All subjects completed the study. After the first period mean nelfinavir AUC(0-24 h), C(max) and C(24) were 49.6 mg h(-1) l(-1), 5.0 mg l(-1) and 0.37 mg l(-1), and the sum of nelfinavir plus its active metabolite M8 C(24) was 0.83 mg l(-1). The relative bioavailability, expressed as a geometric mean ratio (90% confidence interval) for nelfinavir AUC(0-24 h), C(max) and C(24) of period 2 compared with period 1 was: 1.30 (1.21, 1.40), 1.29 (1.19, 1.40) and 1.48 (1.32, 1.66). The sum of nelfinavir and M8 C(24) in period 2 was 0.99 mg l(-1), an increase of 19%. No serious adverse events occurred.

CONCLUSIONS

The studied regimens were well tolerated. Nelfinavir/ritonavir given together with efavirenz resulted in a 48% higher mean C(24) concentration for nelfinavir, and the sum of nelfinavir and M8 C(24) concentrations was 0.99 mg l(-1). Efavirenz exposure in this study was similar to that reported previously, and therefore can be used effectively in combination with ritonavir and nelfinavir.

A randomized study comparing a three- and four-drug HAART regimen in first-line therapy (QUAD study)

BACKGROUND

Evidence from randomized controlled trials supports the use of triple therapy. Research is required on the effectiveness of quadruple therapy in comparison to this and the relative effectiveness of specific highly active antiretroviral therapy (HAART) combinations.

METHODS

Antiretroviral-naive individuals (n = 53) with an HIV-1 viral load >100 000 copies/mL were randomized to receive three-drug HAART with zidovudine/lamivudine (Combivir) and efavirenz or quadruple therapy with zidovudine/lamivudine/abacavir (Trizivir) and efavirenz (quad regimen). Patients continued on HAART for 48 weeks with regular clinical and immunological assessment. Standard and ultrasensitive (<5 copies/mL) viral load testing was carried out.

RESULTS

A DAVG (difference in averages) analysis of the fall in viral load and increase in CD4 count showed no significant differences between regimens. Triple therapy resulted in a -4.17 log change (95% CI, -4.48 to -3.85) and quadruple therapy in a -4.36 log change (95% CI, -4.68 to -4.03) in viral load. For CD4 counts, the triple therapy arm increased by 164 cells/mm(3) (95% CI 112-217) and the quadruple arm by 185 (95% CI, 133-237). In an intent-to-treat analysis, 77% of patients in the triple therapy group reached an undetectable viral load (<50 copies/mL) compared with 84.2% of the quadruple therapy group. For ultrasensitive viral load testing, 23% and 18% of each group, respectively, reached undetectable viral loads. The hazard ratio for attaining a viral load of <5 copies/mL was 0.59 (95% CI, 0.26-1.33) for quadruple versus triple therapy. Three individuals in the triple therapy arm and nine in the quadruple therapy arm discontinued treatment.

CONCLUSIONS

No differences in any analyses were observed between a standard of care regimen (zidovudine/lamivudine and efavirenz) and the quad regimen (zidovudine/lamivudine/abacavir and efavirenz).

Human immunodeficiency virus type-1 accessory protein Vpr: a causative agent of the AIDS-related insulin resistance/lipodystrophy syndrome?

Recent advances in the development of three different types of antiviral drugs, the nucleotide and non-nucleotide analogues acting as reverse transcriptase inhibitors (NRTIs) and the nonpeptidic viral protease inhibitors (PI), and their introduction in the management of patients with AIDS, either alone or in combination, have dramatically improved the clinical course of the disease and prolonged life expectancy in patients with AIDS. The increase in life expectancy in association with the long-term use of the above antiviral agents, however, have generated novel morbidities and complications. Central among them is the quite common AIDS-related insulin resistance and lipodystrophy syndrome, which is characterized by a striking phenotype and marked metabolic disturbances. To look for the pathologic causes of this particular syndrome, we focused on one of the HIV-1 accessory proteins, Vpr, which has multiple functions, such as virion incorporation, nuclear translocation of the HIV-1 preintegration complex, nucleo-cytoplasmic shuttling, transcriptional activation, and induction of apoptosis. Vpr may also act like a hormone, which is secreted into the extracellular space and affects the function of distant organs. Vpr functions as a coactivator of the glucocorticoid receptor and potentiates the action of glucocorticoid hormones, thereby inducing tissue glucocorticoid hypersensitivity. Vpr also arrests host cells at the G2/M phase of the cell cycle by interacting with novel 14-3-3 proteins. Vpr facilitates the interaction of 14-3-3 and its partner protein Cdc25C, which is critical for the transition of G2/M checkpoint in the cell cycle, and suppresses its activity by segregating it into the cytoplasm. The same Vpr protein also suppresses the association of 14-3-3 with other partner molecules, the Foxo transcription factors. Since the Foxo proteins function as negative transcription factors for insulin, Vpr may cause resistance of tissues to insulin. Through these two newly identified functions of Vpr, namely, coactivation of glucocorticoid receptor activity and inhibition of insulin effects on Foxo proteins, Vpr may participate in the development of AIDS-related insulin resistance/lipodystrophy syndrome.

The Antiretroviral-Experienced Patient

There are many considerations for stopping and changing antiretroviral (ARV) therapy in the ARV-experienced individual. Given the potential for possible long-term toxicities and the shift to initiating ARV therapy later, it may be reasonable to stop ARV therapy among asymptomatic patients with high CD4 cell counts and low viral loads and carefully monitor them. Ongoing studies are currently evaluating this strategy. Treatment regimen failure may be due to problems with tolerability, adherence, pharmacokinetic issues, or emergence of resistance. Clinicians can utilize two types of resistance testing-genotype and phenotype assays. Generally, continuation of an optimized regimen in the patient with a multidrug resistant (MDR) virus is the best strategy. Structured treatment interruption among patients with an MDR virus is not recommended. New drugs, either recently licensed, such as enfuvirtide, or under investigation, may offer hope to patients with an MDR virus.

Effects of drug resistance mutations L100I and V106A on the binding of pyrrolobenzoxazepinone nonnucleoside inhibitors to the human immunodeficiency virus type 1 reverse transcriptase catalytic complex

We have previously described a novel class of nonnucleoside reverse transcriptase (RT) inhibitors, the pyrrolobenzoxazepinone (PBO) and the pyridopyrrolooxazepinone (PPO) derivatives, which were effective inhibitors of human immunodeficiency virus type 1 (HIV-1) RT, either wild type or carrying known drug resistance mutations (G. Campiani et al., J. Med. Chem. 42:4462-4470, 1999). The lead compound of the PPO class, (R)-(-)-PPO464, was shown to selectively target the ternary complex formed by the viral RT with its substrates nucleic acid and nucleotide (G. Maga et al., J. Biol. Chem. 276:44653-44662, 2001). In order to better understand the structural basis for this selectivity, we exploited some PBO analogs characterized by various substituents at C-3 and by different inhibition potencies and drug resistance profiles, and we studied their interaction with HIV-1 RT wild type or carrying the drug resistance mutations L100I and V106A. Our kinetic and thermodynamic analyses showed that the formation of the complex between the enzyme and the nucleotide increased the inhibition potency of the compound PBO354 and shifted the free energy (energy of activation, DeltaG(#)) for inhibitor binding toward more negative values. The V106A mutation conferred resistance to PBO 354 by increasing its dissociation rate from the enzyme, whereas the L100I mutation mainly decreased the association rate. This latter mutation also caused a severe reduction in the catalytic efficiency of the RT. These results provide a correlation between the efficiency of nucleotide utilization by RT and its resistance to PBO inhibition.

HIV infection and advanced age emerging epidemiological, clinical, and management issues

While the mean age of HIV/AIDS patients at first diagnosis is progressively rising, no updated epidemiological estimates, controlled clinical data, and randomized therapeutic trials, are available regarding clinical and laboratory response to antiretroviral therapy, safety of anti-HIV compounds and their associations, potential drug-drug interactions, short- and long-term toxicity, consequences on underlying disorders, or interactions with concomitant pharmacological regimens, in the elderly. The life expectancy of HIV-infected persons treated with highly active antiretroviral therapy (HAART) now approximates that of general population matched for age, while also AIDS definition itself has lost most of its epidemiological and clinical significance, thanks to the immunoreconstitution resulting from the large-scale use of potent HAART regimens. The increased survival of HIV-infected patients, the late recognition of other subjects with missed or delayed diagnosis are responsible for a further expected rise of mean age of HIV-infected individuals, so that the patient population aged 60-70 years or more is expected to increase in coming years. Unfortunately, the majority of therapeutic trials involving antiretroviral therapy, as well as antimicrobial chemoprophylaxis for AIDS-related opportunistic complications, have advanced age and/or concurrent end-organ disorders among main exclusion criteria, or the design of these studies does not allow to extrapolate data regarding older patients, compared with younger ones. The very limited data presently available seem to demonstrate that HAART has a virological efficacy in the elderly comparable with that of younger adults, but immunological recovery is often slower and blunted, although several studies clearly demonstrated that thymic function is preserved until late adult age. When facing an HIV-infected patient with advanced age, health care givers have to pay careful attention to eventual end-organ disorders, all possible pharmacological interactions, overlapping toxicity due to concurrent drug administration. All these issues may significantly interfere with HAART activity, patient's adherence to prescribed medications, and frequency and severity of untoward effects. The guidelines of antiretroviral therapy and those of treatment and prophylaxis of AIDS-related diseases deserve appropriate updates, paralleling the increasing mean age of HIV-infected population. Moreover, epidemiological figures need an increased focus on older age, while clinical trials specifically targeting on the elderly population are mandatory to have reliable data on all aspects of HAART administration in advanced age.

Interleukin-4 and interferon-gamma production during HIV-1 infection and changes induced by antiretroviral therapy

Several lines of evidence indicate that a switch of the cytokine pattern from a predominant type 1 (antiviral and cell mediated response) to type 2 (polyclonal humoral immune response) occurs during the course of Human Immunodeficiency Virus-1 (HIV-1) infection, and represents a key event in the progression of immunodeficiency and dysregulated immune activation. We proposed to further investigate this immunological aspect of HIV-1 disease, in naive and in patients treated with Highly Active Antiretroviral Therapy (HAART). The prototypic cytokines chosen were Interleukin (IL)-4 and Interferon-gamma (IFN-gamma), whose in vitro production was determined in mononuclear cell cultures stimulated with different T lymphocyte mitogenic agents (anti-CD3, Phytohaemoagglutin-P -PHA-, E. coli B04/035 Lipopolysaccharide -LPS-). We classified all the patients on the basis of the number of CD4+ lymphocytes and we found a progressive, even if not significant decrease in the baseline production of IFN-gamma with the progression of the immunodeficiency. The mean value of baseline IFN-gamma in the group of patients with CD4+>500 cells/microL was 7.79 +/- 3.1 pg/mL while in the group with CD4+<200 cells/microL it was 4.66 +/- 2.22. We didn't find significant differences in the baseline production of IL-4 in these groups and in IFN-gamma and IL-4 production in LPS-stimulated cultures. We also re-assessed 12 patients after one year's follow-up. They presented a significant increase in IFN-gamma production compared to the first assessment in the LPS-stimulated cultures (baseline IFN-gamma 2.87 +/- 1.17 pg/mL, after 12 months 19.15 +/- 5.19 pg/mL; p= 0.03). In the 12 patients in follow-up IL-4 production showed a decreased in PHA-stimulated cultures with mean values of 16.65 +/- 14.32 pg/mL at baseline and 6.54 +/- 6.54 pg/mL after follow-up. These results highlight the immunorestoring effects of HAART. IL-4 production was lower in the treated subjects compared to the naive ones in PHA-stimulated cultures (mean values: IL-4=13.42 +/- 11.08 pg/mL in the naive patients and 9.75 +/- 65 pg/mL in the treated patients). The IFN-gamma values in anti-CD3 stimulated cultures were also higher in the treated patients, but this increase was not significant.

Total joint arthroplasty in human immunodeficiency virus-positive patients: an alarming rate of early failure

The results of 21 total joint arthroplasties (13 knees, 8 hips) in 15 patients were reviewed. There were 13 men and 2 women with an average age of 38 years (range, 28 to 69 years). The mean follow-up period was 10.2 years (range, 2 to 23 years). Six patients died within an average of 10.6 years (range, 3 to 18 years) of joint arthroplasty. All patients died of AIDS. Deep infection developed in 6 joints. Knee Society scores improved significantly, but 13 repeat surgeries were required. An alarmingly high rate of complications was found after total knee and total hip arthroplasty in these patients with human immunodeficiency virus (HIV). Physicians and surgeons should be made aware of this high rate of complications after joint arthroplasty in patients with HIV and include a frank discussion of this information with their patients who are contemplating total joint arthroplasty.

Adherence to antiretroviral therapy and persistence of HIV RNA in semen

CONTEXT

Long-term adherence to antiretrovirals is critical for sustained virologic response to HIV therapy in blood. Although antiretroviral therapy (ART) reduces HIV seminal shedding, little is known about the relationship between adherence to ART and HIV suppression in semen.

OBJECTIVE

To determine predictors of seminal HIV RNA suppression after 6 months of ART.

DESIGN

Prospective observational cohort of 93 HIV-infected subjects before and after introduction of ART. Seminal HIV RNA was measured at baseline and 1, 2, 3, and 6 months after the introduction of therapy. Adherence to therapy was measured by self-report.

SETTING

A large academic HIV reference center in Rio de Janeiro, Brazil.

MAIN OUTCOME MEASURE

Detectable HIV RNA in semen.

RESULTS

In a multivariate logistic model with undetectable seminal HIV RNA after 6 months of therapy as the outcome variable, adjusting for baseline seminal viral load, both being adherent to therapy (OR = 11.8, < 0.01) and using triple-drug ART (OR = 6.48, = 0.04) were independently associated with seminal HIV RNA suppression.

CONCLUSIONS

Inability to adhere to therapy was strongly associated with persistent shedding of HIV RNA in semen. Measures to improve adherence are urgently needed to reduce the sexual spread of potentially drug-resistant HIV among subjects using antiretrovirals.

The role of Vif during HIV-1 infection: interaction with novel host cellular factors

BACKGROUND

Current research suggests that human immunodeficiency virus type-1 (HIV-1) virion infectivity factor (Vif) acts during viral assembly in producer cells to ensure infectivity in target cells but the exact mechanism of action has not been defined. Vif interacts with Gag, viral protease and RNA and these interactions are proposed to be important for correct particle assembly and stability of the reverse transcription complex.

OBJECTIVES

The existence of cells that are either permissive or non-permissive for replication of Vif deficient viruses suggests the involvement of host cellular factors in its function. Current research suggests an association of Vif with the intermediate filament protein, vimentin, and the tyrosine kinase, Hck, but the significance of these associations remains to be defined. More recently HP68, a cellular ATP binding protein, has been shown to be important for capsid formation and an interaction between Vif and HP68 has been shown. Our aim was to further identify host cellular factors involved in Vif function.

STUDY DESIGN

We have employed the yeast 2-hybrid system to identify cellular proteins which interact with HIV-1 Vif. Sixteen clones were isolated from a high stringency yeast-2-hybrid screen of a human leucocyte cDNA library with Vif derived from the T-cell tropic HIV-1 strain NL4.3. Of these, 8 clones were confirmed as specifically binding Vif, fully sequenced and identified via GenBank homology searches.

RESULTS

Thus far 3 of these clones, spermine/spermidine N1-acetyltransferase, Triad 3 and a novel gene which we have termed 'novel Vif binding protein', have been characterised and represent attractive candidates for mediating Vif action during HIV replication.

CONCLUSIONS

Through identification and characterisation of cellular factors interacting with HIV-1 Vif we hope to unravel the mechanism of action of Vif which may ultimately aid therapeutic design.

Long-term HIV/AIDS survival estimation in the highly active antiretroviral therapy era

BACKGROUND

Highly active antiretroviral therapy (HAART) prolongs short-term survival in patients with HIV/AIDS. HAART has only been available since 1996; thus, no long-term survival data are available. Computer simulation models extrapolating short-term survival data can provide estimates of long-term survival. These survival estimates may assist patients and clinicians in HAART treatment planning. The authors construct a computer simulation model based on observational data to estimate long-term survival in a cohort of HIV/AIDS patients undergoing treatment with HAART.

METHODS

The authors use data from the Collaboration in HIV Outcomes Research-US (CHORUS) observational cohort (N = 4791), the published literature, and US Life Tables to specify a computer simulation model of expected survival accounting for baseline CD4 cell count, progressive HAART treatment failure, progressive risk of HAART on treatment mortality, and age-associated mortality. Time to treatment failure for each of three rounds of HAART and risk of mortality on-treatment were estimated using parametric survival models with censoring of follow-up fit to CHORUS data. Off-treatment survival after HAART failure was estimated from the pre-HAART literature. Age-associated mortality was taken from US Life Tables.

RESULTS

Median projected survivals stratified by baseline CD4 cell count subgroups were CD4 > 200 cells/mm3, 15.4 years; CD4 < or = 200 cells/mm3, 8.5 years; and CD4 < or = 50 cells/mm3, 5.5 years. These values are 4 to 6 years longer than pre-HAART cohorts. The sensitivity analyses showed that the model survival predictions were most sensitive to the treatment failure rate, the on-treatment mortality rate, and the number of treatment rounds.

CONCLUSIONS

Computer simulation modeling of long-term survival of patients with HIV/AIDS on HAART--accounting for differential treatment failure and death rates stratified by CD4 cell count and age-associated mortality--suggests a relatively consistent 4- to 6-year survival benefit over pre-HAART therapies.

Efficacy of induction therapy with high-dose interferon for patients with hemophilia and human immunodeficiency virus-hepatitis C virus coinfection

To evaluate the efficacy of high-dose interferon (IFN) on human immunodeficiency virus (HIV) and hepatitis C virus (HCV) infection, 15 HIV-positive patients and 15 age-matched HIV-negative patients with hemophilia were treated with 9 million units (MU) of IFN-alpha2a daily for 2 weeks, followed by 9 MU of IFN-alpha2a 3 times/week for a further 22 weeks. At week 2, HIV RNA levels decreased from 7410+/-2190 to 320+/-130 copies/mL, and HCV RNA levels decreased from 390x10(3)+/-80x10(3) to 70x10(3)+/-30x10(3) copies/mL in the HIV-positive group and from 300x10(3)+/-80x10(3) to 10x10(3)+/-10x10(3) copies/mL in the HIV-negative group. HCV RNA was undetectable after treatment in 4 of 12 HIV-positive and 6 of 15 HIV-negative patients. IFN therapy was discontinued because of adverse effects in 3 HIV-positive patients. Induction therapy and the dose of IFN should be evaluated in combination therapy with IFN and ribavirin.

HIV disease and advanced age: an increasing therapeutic challenge

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