The evaluation of subcutaneous proleukin (interleukin-2) in a randomized international trial: rationale, design, and methods of ESPRIT

Derivation of a Protein Risk Score for Cardiovascular Disease Among a Multiracial and Multiethnic HIV+ Cohort

Background Cardiovascular disease risk prediction models underestimate CVD risk in people living with HIV (PLWH). Our goal is to derive a risk score based on protein biomarkers that could be used to predict CVD in PLWH. Methods and Results In a matched case-control study, we analyzed normalized protein expression data for participants enrolled in 1 of 4 trials conducted by INSIGHT (International Network for Strategic Initiatives in Global HIV Trials). We used dimension reduction, variable selection and resampling methods, and multivariable conditional logistic regression models to determine candidate protein biomarkers and to generate a protein score for predicting CVD in PLWH. We internally validated our findings using bootstrap. A protein score that was derived from 8 proteins (including HGF [hepatocyte growth factor] and interleukin-6) was found to be associated with an increased risk of CVD after adjustment for CVD and HIV factors (odds ratio: 2.17 [95% CI: 1.58-2.99]). The protein score improved CVD prediction when compared with predicting CVD risk using the individual proteins that comprised the protein score. Individuals with a protein score above the median score were 3.10 (95% CI, 1.83-5.41) times more likely to develop CVD than those with a protein score below the median score. Conclusions A panel of blood biomarkers may help identify PLWH at a high risk for developing CVD. If validated, such a score could be used in conjunction with established factors to identify CVD at-risk individuals who might benefit from aggressive risk reduction, ultimately shedding light on CVD pathogenesis in PLWH.

Increasing procaspase 8 expression using repurposed drugs to induce HIV infected cell death in ex vivo patient cells

HIV persists because a reservoir of latently infected CD4 T cells do not express viral proteins and are indistinguishable from uninfected cells. One approach to HIV cure suggests that reactivating HIV will activate cytotoxic pathways; yet when tested in vivo, reactivating cells do not die sufficiently to reduce cell-associated HIV DNA levels. We recently showed that following reactivation from latency, HIV infected cells generate the HIV specific cytotoxic protein Casp8p41 which is produced by HIV protease cleaving procaspase 8. However, cell death is prevented, possibly due to low procaspase 8 expression. Here, we tested whether increasing procaspase 8 levels in CD4 T cells will produce more Casp8p41 following HIV reactivation, causing more reactivated cells to die. Screening 1277 FDA approved drugs identified 168 that increased procaspase 8 expression by at least 1.7-fold. Of these 30 were tested for anti-HIV effects in an acute HIV_IIIb infection model, and 9 drugs at physiologic relevant levels significantly reduced cell-associated HIV DNA. Primary CD4 T cells from ART suppressed HIV patients were treated with one of these 9 drugs and reactivated with αCD3/αCD28. Four drugs significantly increased Casp8p41 levels following HIV reactivation, and decreased total cell associated HIV DNA levels (flurbiprofen: p = 0.014; doxycycline: p = 0.044; indomethacin: p = 0.025; bezafibrate: P = 0.018) without effecting the viability of uninfected cells. Thus procaspase 8 levels can be increased pharmacologically and, in the context of HIV reactivation, increase Casp8p41 causing death of reactivating cells and decreased HIV DNA levels. Future studies will be required to define the clinical utility of this or similar approaches.

Interleukin-2 as an adjunct to antiretroviral therapy for HIV-positive adults

BACKGROUND

Human immunodeficiency virus (HIV) continues to be a leading cause of morbidity and mortality, particularly in sub-Saharan Africa. Although antiretroviral drugs have helped to improve the quality of life and life expectancy of HIV-positive individuals, there is still a need to explore other interventions that will help to further reduce the disease burden. One potential strategy is the use of interleukin-2 (IL-2) in combination with antiretroviral therapy (ART). IL-2 is a cytokine that regulates the proliferation and differentiation of lymphocytes and may help to boost the immune system.

OBJECTIVES

To assess the effects of interleukin-2 (IL-2) as an adjunct to antiretroviral therapy for HIV-positive adults.

SEARCH METHODS

We searched the following sources up to 26 May 2016: the Cochrane Central Register of Controlled Trials (CENTRAL), published in the Cochrane Library; MEDLINE; Embase; the Web of Science; LILACS; the World Health Organization (WHO) International Clinical Trial Registry Platform (ICTRP); and ClinicalTrials.gov. We also checked conference abstracts, contacted experts and relevant organizations in the field, and checked the reference list of all studies identified by the above methods for any other potentially eligible studies.

SELECTION CRITERIA

Randomized controlled trials (RCTs) that evaluated the effects of IL-2 as an adjunct to ART in reducing the morbidity and mortality in HIV-positive adults.

DATA COLLECTION AND ANALYSIS

Two review authors independently screened records and selected trials that met the inclusion criteria, extracted data, and assessed the risk of bias in the included trials. Where possible, we compared the effects of interventions using risk ratios (RR), and presented them with 95% confidence intervals (CI). We assessed the overall certainty of the evidence using the GRADE approach.

MAIN RESULTS

Following a comprehensive literature search up to 26 May 2016, we identified 25 eligible trials. The interventions involved the use of IL-2 in combination with ART compared with ART alone. There was no difference in mortality apparent between the IL-2 group and the ART alone group (RR 0.97, 95% CI 0.80 to 1.17; 6 trials, 6565 participants, high certainty evidence). Seventeen of 21 trials reported an increase in the CD4 cell count with the use of IL-2 compared to control using different measures (21 trials, 7600 participants). Overall, there was little or no difference in the proportion of participants with a viral load of less than 50 cells/mL or less than 500 cells/mL by the end of the trials (RR 0.97, 95% CI 0.81 to 1.15; 5 trials, 805 participants, high certainty evidence) and (RR 0.96, 95% CI 0.82 to 1.12; 4 trials, 5929 participants, high certainty evidence) respectively. Overall there may be little or no difference in the occurrence of opportunistic infections (RR 0.79, 95% CI 0.55 to 1.13; 7 trials, 6141 participants, low certainty evidence). There was probably an increase in grade 3 or 4 adverse events (RR 1.47, 95% CI 1.10 to 1.96; 6 trials, 6291 participants, moderate certainty evidence). None of the included trials reported adherence.

AUTHORS' CONCLUSIONS

There is high certainty evidence that IL-2 in combination with ART increases the CD4 cell count in HIV-positive adults. However, IL-2 does not confer any significant benefit in mortality, there is probably no difference in the incidence of opportunistic infections, and there is probably an increase in grade 3 or 4 adverse effects. Our findings do not support the use of IL-2 as an adjunct to ART in HIV-positive adults. Based on our findings, further trials are not justified.

Interaction of a Cannabinoid-2 Agonist With Tramadol on Nociceptive Thresholds and Immune Responses in a Rat Model of Incisional Pain

The aim of this study was to elucidate the antinociceptive interaction between cannabinoids and tramadol and their impact on proinflammatory response, in terms of serum intereleukin-6 (IL-6) and interleukin-2 (IL-2) release, in a rat model of incisional pain. Prospective randomized trial assessing the individual or combined application of intraperitoneal tramadol (10 mg/kg) and the selective cannabinoid-2 (CB-2) agonist (R,S)-AM1241 (1 mg/kg) applied postsurgical stress stimulus. Pharmacological specificity was established by antagonizing tramadol with naloxone (0.3 mg/kg) and (R,S)-AM1241 with SR144528 (1 mg/kg). Thermal allodynia was assessed by hot plate test 30 (T30), 60 (T60), and 120 (T120) minutes after incision. Blood samples for plasma IL-6 and IL-2 level determination were obtained 2 hours after incision. Data from 42 rats were included in the final analyses. Significant augmentation of thermal threshold was observed at all time points, after administration of either tramadol or (R,S)-AM1241 compared with the control group (P = 0.004 and P = 0.015, respectively). The combination of (R,S)-AM1241 plus tramadol promoted the induced antinociception in an important manner compared with control (P = 0.002) and (R,S)-AM1241 (P = 0.022) groups. Although the antiallodynic effect produced by tramadol was partially reversed by naloxone 30 and 60 minutes after incision (P = 0.028 and P = 0.016, respectively), SR144528 blocked the effects of (R,S)-AM1241 administration in a significant manner (P = 0.001) at all time points. Similarly, naloxone plus SR144528 also blocked the effects of the combination of (R,S)-AM1241 with tramadol at all time points (P = 0.000). IL-6 level in (R,S)-AM1241 plus tramadol group was significantly attenuated compared with control group (P = 0.000). Nevertheless, IL-2 levels remained unchanged in all experimental groups. It seems that the concomitant administration of a selective CB-2 agonist with tramadol in incisional pain model may improve antinociceptive effects and immune responses of cannabinoids, but this effect does not seem to be superior to that of tramadol alone.

Discordant responses to cART in HIV-1 patients in the era of high potency antiretroviral drugs: clinical evaluation, classification, management prospects

The goal of antiretroviral treatment (ART) in HIV-1 patients is immune reconstitution following control of viral replication. CD4+ cell number/proportions are a crude but essential correlate of immune reconstitution. Despite suppression of HIV replication, a fraction of ART-treated patients still fails to fully reconstitute CD4+ T cell numbers (immunological nonresponders, INRs). New drugs, regimens and treatment strategies led to increased efficacy, lower side effects and higher virological success rates in clinical practice. The multitude of described immune defects and clinical events accompanying INR opposed to the marginal effect of antiretroviral intensification or immunotherapy trials underline the need for continuing efforts at understanding the mechanisms that underlie INR. Here, we reassess INR definition, frequency, and the achievements of active clinical and translational research suggesting a shared definition for insufficient, partial and complete CD4+ cell number recovery thus improving homogeneity in patient selection and mechanism identification.

Circulating microRNAs in Sera Correlate with Soluble Biomarkers of Immune Activation but Do Not Predict Mortality in ART Treated Individuals with HIV-1 Infection: A Case Control Study

Introduction

The use of anti-retroviral therapy (ART) has dramatically reduced HIV-1 associated morbidity and mortality. However, HIV-1 infected individuals have increased rates of morbidity and mortality compared to the non-HIV-1 infected population and this appears to be related to end-organ diseases collectively referred to as Serious Non-AIDS Events (SNAEs). Circulating miRNAs are reported as promising biomarkers for a number of human disease conditions including those that constitute SNAEs. Our study sought to investigate the potential of selected miRNAs in predicting mortality in HIV-1 infected ART treated individuals.

Materials and Methods

A set of miRNAs was chosen based on published associations with human disease conditions that constitute SNAEs. This case: control study compared 126 cases (individuals who died whilst on therapy), and 247 matched controls (individuals who remained alive). Cases and controls were ART treated participants of two pivotal HIV-1 trials. The relative abundance of each miRNA in serum was measured, by RTqPCR. Associations with mortality (all-cause, cardiovascular and malignancy) were assessed by logistic regression analysis. Correlations between miRNAs and CD4+ T cell count, hs-CRP, IL-6 and D-dimer were also assessed.

Results

None of the selected miRNAs was associated with all-cause, cardiovascular or malignancy mortality. The levels of three miRNAs (miRs -21, -122 and -200a) correlated with IL-6 while miR-21 also correlated with D-dimer. Additionally, the abundance of miRs -31, -150 and -223, correlated with baseline CD4+ T cell count while the same three miRNAs plus miR-145 correlated with nadir CD4+ T cell count.

Discussion

No associations with mortality were found with any circulating miRNA studied. These results cast doubt onto the effectiveness of circulating miRNA as early predictors of mortality or the major underlying diseases that contribute to mortality in participants treated for HIV-1 infection.

Severity of cardiovascular disease outcomes among patients with HIV is related to markers of inflammation and coagulation

Background

In the general population, raised levels of inflammatory markers are stronger predictors of fatal than nonfatal cardiovascular disease (CVD) events. People with HIV have elevated levels of interleukin‐6 (IL‐6), high‐sensitivity C‐reactive protein (hsCRP), and D‐dimer; HIV‐induced activation of inflammatory and coagulation pathways may be responsible for their greater risk of CVD. Whether the enhanced inflammation and coagulation associated with HIV is associated with more fatal CVD events has not been investigated.

Methods and Results

Biomarkers were measured at baseline for 9764 patients with HIV and no history of CVD. Of these patients, we focus on the 288 that experienced either a fatal (n=74) or nonfatal (n=214) CVD event over a median of 5 years. Odds ratios (ORs) (fatal versus nonfatal CVD) (95% confidence intervals [CIs]) associated with a doubling of IL‐6, D‐dimer, hsCRP, and a 1‐unit increase in an IL‐6 and D‐dimer score, measured a median of 2.6 years before the event, were 1.39 (1.07 to 1.79), 1.40 (1.10 to 1.78), 1.09 (0.93 to 1.28), and 1.51 (1.15 to 1.97), respectively. Of the 214 patients with nonfatal CVD, 23 died during follow‐up. Hazard ratios (95% CI) for all‐cause mortality were 1.72 (1.28 to 2.31), 1.73 (1.27 to 2.36), 1.44 (1.15 to 1.80), and 1.88 (1.39 to 2.55), respectively, for IL‐6, D‐dimer, hsCRP, and the IL‐6 and D‐dimer score.

Conclusions

Higher IL‐6 and D‐dimer levels reflecting enhanced inflammation and coagulation associated with HIV are associated with a greater risk of fatal CVD and a greater risk of death after a nonfatal CVD event.

Clinical Trial Registration

URL: http://www.clinicaltrial.gov Unique identifier: SMART: NCT00027352, ESPRIT: NCT00004978, SILCAAT: NCT00013611.

E-survey with researchers, members of ethics committees and sponsors of clinical research in Brazil: an emerging methodology for scientific research

INTRODUCTION: The growth of Internet users enables epidemiological studies to be conducted electronically, representing a promising methodology for data collection. METHODS: Members of Ethics Committees, Clinical Researchers and Sponsors were interviewed using questionnaires sent over the Internet. Along with the questionnaire, participants received a message explaining the survey and also the informed consent. Returning the questionnaire meant the consent of the participant was given. No incentive was offered; two reminders were sent. RESULTS: The response rate was 21% (124/599), 20% (58/290) and 45% (24/53) respectively for Ethics Committees, Researchers and Sponsors. The percentage of return before the two reminders was about 62%. Reasons for non-response: participant not found, refusal to participate, lack of experience in clinical research or in the therapeutic field. Characteristics of participants: 45% of Ethics Committee participants, 64% of Researchers and 63% of Sponsors were male; mean age (range), respectively: 47 (28-74), 53 (24-72) and 40 (29-65) years. Among Researchers and Sponsors, all respondents had at least a university degree and, in the Ethics Committees group, only two (1.7%) did not have one. Most of the questionnaires in all groups came from the Southeast Region of Brazil, probably reflecting the highest number of clinical trials and research professionals in this region. CONCLUSION: Despite the potential limitations of a survey done through the Internet, this study led to a response rate similar to what has been observed with other models, efficiency in obtaining responses (speed and quality), convenience for respondents and low cost.

The CD4 lymphocyte count and risk of clinical progression

PURPOSE OF REVIEW

The CD4 lymphocyte count was identified as a key predictor of risk of AIDS defining diseases almost 20 years ago, early in the HIV epidemic. Several issues concerning its use to predict AIDS have arisen since. These include the difference between short and long-term prediction, the use of CD4 percentage compared with absolute counts, the impact of antiretroviral therapy on the predictive value of the CD4 count, the role relative to other markers such as viral load, the derivation of scores to predict AIDS diseases, the use of CD4 count as a surrogate endpoint, the role of the CD4 count nadir compared with the current value and the differential ability to predict different AIDS diseases.

RECENT FINDINGS

All the above issues have been clarified further and this process has continued through 2004 and 2005. These developments are briefly described in this review.

SUMMARY

The CD4 count remains the strongest short-term predictor of risk of AIDS so far identified in both treated and untreated patients and should continue to be a mainstay of monitoring for both untreated and treated patients.

Reclassification of risk of death with the knowledge of D-dimer in a cohort of treated HIV-infected individuals

OBJECTIVE

To evaluate the change in categories of risk of death by adding D-dimer to conventional mortality risk factors.

DESIGN

Cohort study.

METHODS

Data on HIV-infected participants receiving standard combination antiretroviral therapy in two clinical trials (Evaluation of Subcutaneous Proleukin in a Randomized International Trial and Strategic Management of antiretroviral therapy), who had baseline D-dimer measured, were randomly split into two equal training and a validation datasets. A multivariable survival model was built using the training dataset and included only conventional mortality risk factors measured at baseline. D-dimer was added to create the comparison model. The level of reclassification of mortality risk, for those with at least 5-years of follow-up, was then assessed by tabulating mortality risk defined as low (≤2% predicted rate), moderate (2-5%) or high (>5%). Reclassification analyses were then repeated on the validation dataset.

RESULTS

The analysis population at baseline had a mean age of 43 years, median CD4(+) cell count of 535 cells/μl (IQR: 420-712), and 83% had HIV RNA of at least 500 copies/ml. In the training dataset (n=1946, 8939 person-years), there were 83 deaths at a rate of 0.93 per 100 person-years. Addition of D-dimer to the reference model resulted in 6% or fewer (P>0.05) being correctly reassigned, either up or down, to a new risk category, in both, training and validation datasets. The integrated discrimination improvement in training and validation datasets was 0.60% (P=0.084) and 0.45% (P=0.168), respectively.

CONCLUSION

In this relatively well population, at the given risk cutoffs, D-dimer appeared to only modestly improve the discernment of risk. Risk reclassification provides a method for assessing the clinical utility of biomarkers in HIV cohort studies.

HIV RNA suppression and immune restoration: can we do better?

HAART has significantly changed the natural history of HIV infection: patients receiving antiretrovirals are usually able to control viremia, even though not all virological responders adequately recover their CD4+ count. The reasons for poor immune restoration are only partially known and they include genetic, demographic and immunologic factors. A crucial element affecting immune recovery is immune activation, related to residual viremia; indeed, a suboptimal virological control (i.e., low levels of plasma HIV RNA) has been related with higher levels of chronic inflammation and all-cause mortality. The sources of residual viremia are not yet completely known, even though the most important one is represented by latently infected cells. Several methods, including 2-LTR HIV DNA and unspliced HIV RNA measurement, have been developed to estimate residual viremia and predict the outcome of antiretroviral therapy. Considering that poor immunologic responders are exposed to a higher risk of both AIDS-related and non-AIDS-related diseases, there is a need of new therapeutic strategies, including immunomodulators and drugs targeting the latent viral reservoirs, in order to face residual viremia but also to “drive” the host immunologic responses.

Empirical evaluation of the need for 'on-going consent' in clinical research

OBJECTIVE

Some commentators argue that informed consent for clinical research should be an on-going process, which begins, rather than ends, with participants' initial consent. Lacking, however, are empirical data on whether there is a need for 'on-going consent'.

DESIGN

Two self-administered surveys - a baseline survey at initial consent and a follow-up survey 2-3 years later - to assess whether participants remain informed over time.

METHODS

Respondents were adults with HIV disease from Argentina, Brazil and Thailand enrolled in a long-term clinical trial.

RESULTS

Respondents overall were well informed at baseline. At follow-up, many reported being not informed about aspects of the study central to their on-going participation. With respect to the possibility of withdrawal, 38.5% of respondents at follow-up reported being 'not at all' informed. At follow-up, 71.1% wanted more information. Yet, 62.8% had not asked any questions during the entire study. Reasons for not asking questions included not having an opportunity (16.4%) and not knowing whom to ask (15.5%).

CONCLUSIONS

The standard consent process resulted in participants being well informed at enrollment. Yet, this process was not sufficient to keep them informed about aspects of the study central to their on-going participation. In addition, participants who wanted more information often did not ask for it. These findings provide empirical support for recommendations that clinical trials should consider including a process of 'on-going consent'.

Predictors of bacterial pneumonia in Evaluation of Subcutaneous Interleukin-2 in a Randomized International Trial (ESPRIT)

BACKGROUND AND OBJECTIVES

Bacterial pneumonia still contributes to morbidity/mortality in HIV infection despite effective combination antiretroviral therapy (cART). Evaluation of Subcutaneous Interleukin-2 in a Randomized International Trial (ESPRIT), a trial of intermittent recombinant interleukin-2 (rIL-2) with cART vs. cART alone (control arm) in HIV-infected adults with CD4 counts ≥300cells/μL, offered the opportunity to explore associations between bacterial pneumonia and rIL-2, a cytokine that increases the risk of some bacterial infections.

METHODS

Baseline and time-updated factors associated with first-episode pneumonia on study were analysed using multivariate proportional hazards regression models. Information on smoking/pneumococcal vaccination history was not collected.

RESULTS

IL-2 cycling was most intense in years 1-2. Over ≈7 years, 93 IL-2 [rate 0.67/100 person-years (PY)] and 86 control (rate 0.63/100 PY) patients experienced a pneumonia event [hazard ratio (HR) 1.06; 95% confidence interval (CI) 0.79, 1.42; P=0.68]. Median CD4 counts prior to pneumonia were 570cells/μL (IL-2 arm) and 463cells/μL (control arm). Baseline risks for bacterial pneumonia included older age, injecting drug use, detectable HIV viral load (VL) and previous recurrent pneumonia; Asian ethnicity was associated with decreased risk. Higher proximal VL (HR for 1 log(10) higher VL 1.28; 95% CI 1.11, 1.47; P<0.001) was associated with increased risk; higher CD4 count prior to the event (HR per 100 cells/μL higher 0.94; 95% CI 0.89, 1.0; P=0.04) decreased risk. Compared with controls, the hazard for a pneumonia event was higher if rIL-2 was received <180 days previously (HR 1.66; 95% CI 1.07, 2.60; P=0.02) vs.≥180 days previously (HR 0.98; 95% CI 0.70, 1.37; P=0.9). Compared with the control group, pneumonia risk in the IL-2 arm decreased over time, with HRs of 1.41, 1.71, 1.16, 0.62 and 0.84 in years 1, 2, 3-4, 5-6 and 7, respectively.

CONCLUSIONS

Bacterial pneumonia rates in cART-treated adults with moderate immunodeficiency are high. The mechanism of the association between bacterial pneumonia and recent IL-2 receipt and/or detectable HIV viraemia warrants further exploration.

Role of interleukin-2 in patients with HIV infection

Control of viral replication to below the level of quantification using combination antiretroviral therapy (ART) [cART] has led to a dramatic fall in mortality and morbidity from AIDS. However, despite the success of cART, it has become apparent that many patients do not achieve normalized CD4+ T-cell counts despite virological suppression to below the level of quantification (<50 copies/mL). Increasing data from cohort studies and limited data from clinical trials, such as the SMART study, have shown that higher CD4+ T-cell counts are associated with reductions in morbidity and mortality from both AIDS and serious non-AIDS (SNA) conditions, including cardiovascular disease. Enhancement of immune restoration over and above that achievable with ART alone, using a number of strategies including cytokine therapy, has been of interest for many years. The most studied cytokine in this setting is recombinant interleukin (IL)-2 (rIL-2). The purpose of this review is to describe the current status of rIL-2 as a therapeutic agent in the treatment of HIV-1 infection. The review focuses on the rationale underpinning the exploration of rIL-2 in HIV infection, summarizing the phase II and III findings of rIL-2 as an adjunctive therapy to ART and the phase II studies of rIL-2 as an antiretroviral-sparing agent. The phase II studies demonstrated the potential utility of continuous intravenous IL-2 and subsequently intermittent dosing with subcutaneous rIL-2 as a cytokine that could expand the CD4+ T-cell pool in HIV-1-infected patients without any significant detrimental effect on HIV viral load and with an acceptable adverse-effect profile. These data were utilized in designing the phase II studies of rIL-2 as an ART-sparing agent and, more importantly, the large phase III clinical endpoint studies of rIL-2 in HIV-1-infected adults, ESPRIT and SILCAAT. In the latter, subcutaneous rIL-2 was given intermittently (5 days of twice-daily dosing at 4.5-7.5 million international units per dose every 8 weeks) to HIV-1-infected adults receiving cART using an induction/maintenance strategy. Both studies explored the clinical benefit of intermittent subcutaneous rIL-2 with cART versus cART in HIV-infected adults with CD4+ T-cell counts > or = 300 cells/microL (ESPRIT study) and 50-299 cells/microL (SILCAAT study). Both studies showed that receipt of rIL-2 conferred no clinical benefit despite a significantly higher CD4+ T-cell count in the rIL-2 arms of both studies. Moreover, there was an excess of grade 4 clinical events in ESPRIT rIL-2 recipients. The results of the phase III clinical endpoint studies showed that rIL-2 has no place as a therapeutic agent in the treatment of HIV infection.

Immunodeficiency and the risk of serious clinical endpoints in a well studied cohort of treated HIV-infected patients

OBJECTIVE

To investigate the relative predictive value of CD4(+) metrics for serious clinical endpoints.

DESIGN

Observational.

METHODS

Patients (3012; 20 317 person-years) from control arms of ESPRIT and SILCAAT were followed prospectively. We used Cox regression to identify CD4(+) metrics (latest, baseline and nadir CD4(+) cell count, latest CD4(+)%, time spent with CD4(+) count below certain thresholds and CD4(+) slopes) independently predictive of all-cause mortality, non-AIDS deaths, non-AIDS (cardiovascular, hepatic, renal and non-AIDS malignancy) and AIDS events. Akaike information criteria (AIC) were calculated for each model. Significant metrics (P < 0.05) were then additionally adjusted for latest CD4(+) cell count.

RESULTS

Non-AIDS deaths occurred at a higher rate than AIDS deaths [rate ratio: 6.48, 95% confidence interval (CI) 5.1-8.1], and non-AIDS events likewise (rate ratio: 1.72, 95% CI 1.65-1.79). Latest CD4(+) cell count was strongly predictive of lower risk of death (hazard ratio per log2 rise: 0.48, 95% CI 0.43-0.54), with lowest AIC of all metrics. CD4(+) slope over seven visits, after additional adjustment for latest CD4(+) cell count, was the only metric to be an independent predictor for all-cause (hazard ratio for slope <-10 cells/microl per month vs. 0 +/- 10: 3.04, 95% CI 1.98-4.67) and non-AIDS deaths (hazard ratio for slope <-10 cells/microl per month vs. 0 +/- 10: 2.62, 95% CI 1.62-4.22). Latest CD4(+) cell count (per log(2) rise) was the best predictor across all four endpoints and predicted hepatic (hazard ratio 0.46, 95% CI 0.33-0.63) and renal events (hazard ratio 0.39, 95% CI 0.21-0.70), but not cardiovascular events (hazard ratio 1.05, 95% CI 0.77-1.43) or non-AIDS cancers (hazard ratio 0.78, 95% CI 0.59-1.03).

CONCLUSION

Latest CD4(+) cell count is the best predictor of serious endpoints. CD4(+) slope independently predicts all-cause and non-AIDS deaths.

Designing and implementing sample and data collection for an international genetics study: the Type 1 Diabetes Genetics Consortium (T1DGC)

BACKGROUND AND PURPOSE

The Type 1 Diabetes Genetics Consortium (T1DGC) is an international project whose primary aims are to: (a) discover genes that modify type 1 diabetes risk; and (b) expand upon the existing genetic resources for type 1 diabetes research. The initial goal was to collect 2500 affected sibling pair (ASP) families worldwide.

METHODS

T1DGC was organized into four regional networks (Asia-Pacific, Europe, North America, and the United Kingdom) and a Coordinating Center. A Steering Committee, with representatives from each network, the Coordinating Center, and the funding organizations, was responsible for T1DGC operations. The Coordinating Center, with regional network representatives, developed study documents and data systems. Each network established laboratories for: DNA extraction and cell line production; human leukocyte antigen genotyping; and autoantibody measurement. Samples were tracked from the point of collection, processed at network laboratories and stored for deposit at National Institute for Diabetes and Digestive and Kidney Diseases (NIDDK) Central Repositories. Phenotypic data were collected and entered into the study database maintained by the Coordinating Center.

RESULTS

T1DGC achieved its original ASP recruitment goal. In response to research design changes, the T1DGC infrastructure also recruited trios, cases, and controls. Results of genetic analyses have identified many novel regions that affect susceptibility to type 1 diabetes. T1DGC created a resource of data and samples that is accessible to the research community.

LIMITATIONS

Participation in T1DGC was declined by some countries due to study requirements for the processing of samples at network laboratories and/or final deposition of samples in NIDDK Central Repositories. Re-contact of participants was not included in informed consent templates, preventing collection of additional samples for functional studies.

CONCLUSIONS

T1DGC implemented a distributed, regional network structure to reach ASP recruitment targets. The infrastructure proved robust and flexible enough to accommodate additional recruitment. T1DGC has established significant resources that provide a basis for future discovery in the study of type 1 diabetes genetics.

Quality control of phenotypic forms data in the Type 1 Diabetes Genetics Consortium

Background When collecting phenotypic data in clinics across the globe, the Type 1 Diabetes Genetics Consortium (T1DGC) used several techniques that ensured consistency, completeness, and accuracy of the data.

Purpose The aim of this article is to describe the procedures used for collection, entry, processing, and management of the phenotypic data in this international study.

Methods The T1DGC ensured the collection of high quality data using the following procedures throughout the entire study period. The T1DGC used centralized and localized training, required a pilot study, certified all data entry personnel, created standardized data collection forms, reviewed a sample of form sets quarterly throughout the duration of the study, and used a data entry system that provided immediate feedback to those entering the data.

Results Due to the intensive procedures in developing the forms, the study was able to uphold consistency among all clinics and minimal changes were required after implementation of the forms. The train-the-trainer model was efficient and only a small number of clinics had to repeat a pilot study. The study was able to maintain a low percentage of missing data (<0.001%) and low duplicate data entry error rate (0.10%).

Conclusions It is critical to provide immediate follow-up in order to reinforce training and ensure the quality of the data collected and entered.

Changes in the levels of some acute-phase proteins in human immunodeficiency virus-1 infected patients, following interleukin-2 treatment

Intermittent interleukin (IL)-2 administration to human immunodeficiency virus (HIV)-1 infected patients is well documented and generally used, but there is limited information about the changes of acute-phase protein (APP) levels in response to this treatment. Fifteen patients undergoing highly active anti-retroviral therapy (HAART) treatment, with undetectable viral load, but low CD4+ cell count (<300/microl), have been treated with 3.6 M IU Proleukine administered twice daily by subcutaneous injection over 5 days. C-reactive protein (CRP), D-dimer, C3, C9, C1-inh and alpha-2HS glycoprotein levels were measured immediately before IL-2 administration, as well as on day 5 and 2-3 weeks thereafter. After IL-2 administration, both mean D-dimer and CRP levels increased significantly (P<0.001), but returned (P<0.001) to baseline within the subsequent 2-3 weeks. Alpha-2HS glycoprotein decreased immediately after IL-2 administration. No significant differences were detected in the levels of C3, C9 and C1-inh. A significant, positive correlation (r=0.5178, P=0.0008) was ascertained between the changes of CRP level, measured immediately before as well as 5 days after IL-2 administration, and changes in CD4 T cell counts measured 2-3 weeks before and after treatment, respectively. IL-2 administration induces rapid elevation of two major APPs (CRP, D-dimer). The positive correlation observed between the changes of CRP levels and CD4+ cell counts after IL-2 administration may indicate that the abrupt, but transitory overproduction of CRP might contribute to the CD4+ cell count-increasing effect of the drug and/ or may be associated with serious side effects.

Risk of all-cause mortality associated with nonfatal AIDS and serious non-AIDS events among adults infected with HIV

OBJECTIVES

Among patients with HIV, the risk of death associated with different AIDS events has been quantified, but the risk of death associated with non-AIDS events has not been examined. We compared the risk of all-cause mortality following AIDS versus serious non-AIDS (SNA) events in the Strategies for Management of Antiretroviral Therapy (SMART) study and the Evaluation of Subcutaneous Proleukin in a Randomized International Trial (ESPRIT).

DESIGN

Data from 9583 HIV-infected participants, 5472 with a CD4 cell count more than 350 cells/microl enrolled in SMART and 4111 with a CD4 cell count 300 cells/microl or more enrolled in ESPRIT, were analyzed.

METHODS

Cumulative mortality 6 months after AIDS and SNA events (cardiovascular, renal, hepatic disease, and malignancies) was estimated using the Kaplan-Meier method. Cox models were used to estimate hazard ratios associated with AIDS and SNA events on the risk of death overall and by treatment group within study.

RESULTS

AIDS and SNA events occurred in 286 and 435 participants with 47 (16%) and 115 (26%) subsequent deaths, respectively. Six-month cumulative mortality was 4.7% [95% confidence interval (CI) 2.8-8.0] after experiencing an AIDS event and 13.4% (95% CI 10.5-17.0) after experiencing an SNA event. The adjusted hazard ratio for all-cause mortality for those who experienced AIDS versus those who did not was 4.9 (95% CI 3.6-6.8). The corresponding hazard ratio for SNA was 11.4 (95% CI 9.0-14.5) (P < 0.001 for difference in hazard ratios). Findings were similar for both treatment groups in SMART and both treatment groups in ESPRIT.

CONCLUSION

Among HIV-infected persons with higher CD4 cell counts, SNA events occur more frequently and are associated with a greater risk of death than AIDS events. Future research should be aimed at comparing strategies to reduce morbidity and mortality associated with SNA events for HIV-infected persons.

Efficacy and safety of etravirine in treatment-experienced, HIV-1 patients: pooled 48 week analysis of two randomized, controlled trials

OBJECTIVE

To evaluate the efficacy, safety and virologic resistance profile of etravirine (TMC125), a next-generation nonnucleoside reverse transcriptase inhibitor, over 48 weeks in treatment-experienced adults infected with HIV-1 strains resistant to a nonnucleoside reverse transcriptase inhibitor and other antiretrovirals.

DESIGN

DUET-1 (NCT00254046) and DUET-2 (NCT00255099) are two identically designed, randomized, double-blind phase III trials.

METHODS

Patients received twice-daily etravirine 200 mg or placebo, each plus a background regimen of darunavir/ritonavir, investigator-selected nucleoside/nucleotide reverse transcriptase inhibitors and optional enfuvirtide. Eligible patients had documented nonnucleoside reverse transcriptase inhibitor resistance, at least three primary protease inhibitor mutations at screening and were on a stable but virologically failing regimen for at least 8 weeks, with plasma viral load more than 5000 copies/ml. Pooled 48-week data from the two trials are presented.

RESULTS

Patients (1203) were randomized and treated (n = 599, etravirine; n = 604, placebo). Significantly more patients in the etravirine than in the placebo group achieved viral load less than 50 copies/ml at week 48 (61 vs. 40%, respectively; P < 0.0001). Significantly fewer patients in the etravirine group experienced at least one confirmed or probable AIDS-defining illness/death (6 vs. 10%; P = 0.0408). Safety and tolerability in the etravirine group was comparable to the placebo group. Rash was the only adverse event to occur at a significantly higher incidence in the etravirine group (19 vs. 11%, respectively, P < 0.0001), occurring primarily in the second week of treatment.

CONCLUSION

At 48 weeks, treatment-experienced patients receiving etravirine plus background regimen had statistically superior and durable virologic responses (viral load less than 50 copies/ml) than those receiving placebo plus background regimen, with comparable tolerability and no new safety signals reported since week 24.

Interleukin-2 therapy in patients with HIV infection

BACKGROUND

Used in combination with antiretroviral therapy, subcutaneous recombinant interleukin-2 raises CD4+ cell counts more than does antiretroviral therapy alone. The clinical implication of these increases is not known.

METHODS

We conducted two trials: the Subcutaneous Recombinant, Human Interleukin-2 in HIV-Infected Patients with Low CD4+ Counts under Active Antiretroviral Therapy (SILCAAT) study and the Evaluation of Subcutaneous Proleukin in a Randomized International Trial (ESPRIT). In each, patients infected with the human immunodeficiency virus (HIV) who had CD4+ cell counts of either 50 to 299 per cubic millimeter (SILCAAT) or 300 or more per cubic millimeter (ESPRIT) were randomly assigned to receive interleukin-2 plus antiretroviral therapy or antiretroviral therapy alone. The interleukin-2 regimen consisted of cycles of 5 consecutive days each, administered at 8-week intervals. The SILCAAT study involved six cycles and a dose of 4.5 million IU of interleukin-2 twice daily; ESPRIT involved three cycles and a dose of 7.5 million IU twice daily. Additional cycles were recommended to maintain the CD4+ cell count above predefined target levels. The primary end point of both studies was opportunistic disease or death from any cause.

RESULTS

In the SILCAAT study, 1695 patients (849 receiving interleukin-2 plus antiretroviral therapy and 846 receiving antiretroviral therapy alone) who had a median CD4+ cell count of 202 cells per cubic millimeter were enrolled; in ESPRIT, 4111 patients (2071 receiving interleukin-2 plus antiretroviral therapy and 2040 receiving antiretroviral therapy alone) who had a median CD4+ cell count of 457 cells per cubic millimeter were enrolled. Over a median follow-up period of 7 to 8 years, the CD4+ cell count was higher in the interleukin-2 group than in the group receiving antiretroviral therapy alone--by 53 and 159 cells per cubic millimeter, on average, in the SILCAAT study and ESPRIT, respectively. Hazard ratios for opportunistic disease or death from any cause with interleukin-2 plus antiretroviral therapy (vs. antiretroviral therapy alone) were 0.91 (95% confidence interval [CI], 0.70 to 1.18; P=0.47) in the SILCAAT study and 0.94 (95% CI, 0.75 to 1.16; P=0.55) in ESPRIT. The hazard ratios for death from any cause and for grade 4 clinical events were 1.06 (P=0.73) and 1.10 (P=0.35), respectively, in the SILCAAT study and 0.90 (P=0.42) and 1.23 (P=0.003), respectively, in ESPRIT.

CONCLUSIONS

Despite a substantial and sustained increase in the CD4+ cell count, as compared with antiretroviral therapy alone, interleukin-2 plus antiretroviral therapy yielded no clinical benefit in either study. (ClinicalTrials.gov numbers, NCT00004978 [ESPRIT] and NCT00013611 [SILCAAT study].)

Interleukin-2 cycling causes transient increases in high-sensitivity C-reactive protein and D-dimer that are not associated with plasma HIV-RNA levels

OBJECTIVE

To determine the effects of interleukin (IL)-2 treatment on inflammatory and thrombotic biomarkers in chronically HIV-infected adults receiving antiretroviral therapy.

METHODS

Cryopreserved plasma was evaluated retrospectively for C-reactive protein (CRP) and D-dimer at baseline, end of an IL-2 cycle, and long-term follow up from two randomized, controlled trials: 57 IL-2-naive adults receiving either three to six cycles of IL-2 as well as antiretroviral therapy (nucleoside analogues) or antiretroviral therapy alone for 12 months, and 40 IL-2-experienced adults on highly active antiretroviral therapy who either interrupted or continued therapy for 6 months after a baseline IL-2 cycle. High-sensitivity CRP (hsCRP) was measured by immunonephelometry (detection limit 0.175 mg/l) and D-dimer by latex agglutination (detection limit 0.20 mg/l). Median within-group differences and pre and post-IL-2 changes between groups were assessed via nonparametric Wilcoxon signed-rank and Mann-Whitney U-tests. Spearman's rank test was used to assess correlations between changes in hsCRP, D-dimer, and HIV-RNA viral load.

RESULTS

Significant increases in hsCRP (study 1: 138.6 mg/l; study 2: 58.9 mg/l) and D-dimer (study 1: 3.1 mg/l; study 2: 0.4 mg/l, all P < 0.0001) occurred by the end of the initial IL-2 cycle, returning to baseline by the end of study. No correlations were seen between changes in hsCRP or D-dimer and HIV-RNA, CD4 T-cell count, or proliferation (Ki67 expression). No thrombotic or cardiovascular serious adverse events occurred during these study periods.

CONCLUSION

IL-2 dosing caused transient increases in plasma hsCRP and D-dimer levels, regardless of HIV-RNA viral load, suggesting the possibility of increased risk for thrombotic events.

Benefits and burdens of participation in a longitudinal clinical trial

SYSTEMATIC DATA ON THE IMPACT THAT longitudinal clinical trials have on patient participants are needed to ensure that all the risks and potential benefits of participating in clinical research are properly evaluated and disclosed. Recognizing the lack of systematic data on this topic, we surveyed 582 individuals from Argentina, Brazil, and Thailand who were participating in the ESPRIT study, a Phase III randomized trial of interleukin-2 in HIV disease. Respondents were asked about the benefits and burdens of participating in ESPRIT using a self-administered survey. We found that 91% of respondents in the IL-2 treatment arm and 79% in the no IL-2 control arm reported medical benefits from their participation. In addition, 68% in the IL-2 treatment arm and 60% of the no IL-2 controls reported non-medical benefits. Thirteen percent of the IL-2 respondents and 5% of the non-IL2 respondents reported problems with their jobs due to study participation. Given that respondents, including those in the control arm, reported medical and non-medical benefits and burdens from their research participation, investigators and review committees should be aware of and respond to the potential for research participants to experience benefits and burdens that are unrelated to the intervention being tested.

Immunotherapies in HIV-1 infection

PURPOSE OF REVIEW

The purpose of this review is to describe the current status of immunotherapies for the treatment of HIV-1 infection. This review is timely, as the results of the phase III clinical trials of recombinant interleukin-2 (rIL-2) as adjuncts to combination antiretroviral therapy are about to be released.

RECENT FINDINGS

For many years, the use of rIL-2 in HIV-infected individuals has been explored. Although the results of the clinical endpoint studies of rIL-2 are awaited, there are now further data for rIL-2 as a stand-alone therapy for the treatment of HIV. Maraviroc, a recently approved anti-HIV agent, is a small molecule antagonist of human chemokine receptor-5. The recent observation that maraviroc-treated patients achieved higher CD4 and CD8 T-cell counts compared with comparator regimens (without a chemokine receptor-5 antagonist) for equivalent viral load reductions has fueled interest in using these host-directed therapies to enhance immune restoration.

SUMMARY

This review summarizes the most recent clinical data for rIL-2 and reviews other immunotherapies in earlier development including cytokines rIL-7, rIL-15, rIL-21, new therapeutic vaccination approaches including infusion of overlapping HIV peptides and dendritic cell immunotherapy and novel agents including luteinizing hormone-releasing hormone analogues and vitamin D3-binding protein macrophage activating factor.

IL-7 administration drives T cell-cycle entry and expansion in HIV-1 infection

Interleukin 7 (IL-7) is a common gamma chain receptor cytokine implicated in thymopoiesis and in peripheral expansion and survival of T lymphocytes. The safety and activity of recombinant human IL-7 (rhIL-7) administration were therefore examined in HIV-infected persons. In this prospective randomized placebo-controlled study, a single subcutaneous dose of rhIL-7 was well tolerated with biologic activity demonstrable at 3 microg/kg and a maximum tolerated dose of 30 microg/kg. Injection site reactions and transient elevations of liver function tests were the most notable side effects. Transient increases in plasma HIV-RNA levels were observed in 6 of 11 IL-7-treated patients. Recombinant hIL-7 induced CD4 and CD8 T cells to enter cell cycle; cell-cycle entry was also confirmed in antigen-specific CD8 T cells. Administration of rhIL-7 led to transient down-regulation of the IL-7 receptor alpha chain (CD127) in both CD4(+) and CD8(+) T cells. Single-dose rhIL-7 increased the numbers of circulating CD4(+) and CD8(+) T cells, predominantly of central memory phenotype. The frequency of CD4(+) T cells with a regulatory T-cell phenotype (CD25(high) CD127(low)) did not change after rhIL-7 administration. Thus, rhIL-7 has a biologic and toxicity profile suggesting a potential for therapeutic trials in HIV infection and other settings of lymphopenia. This clinical trial has been registered at http://www.clinicaltrials.gov under NCT0099671.

Inferiority of IL-2 alone versus IL-2 with HAART in maintaining CD4 T cell counts during HAART interruption: a randomized controlled trial

OBJECTIVE

To evaluate whether interleukin (IL)-2 in patients with chronic HIV infection can maintain CD4 T cell counts during 6 months of HAART interruption.

DESIGN

Prospective, randomized, controlled, open-label phase II noninferiority trial comparing IL-2 with HAART interruption or continuous HAART.

METHODS

Forty-one IL-2-experienced (three or more prior cycles) HIV-1-infected adults with CD4 cell count at least 500 cells/microl were randomized in the ratio 2: 1 to interrupted (I = 27) or continuous (C = 14) HAART for 6 months following an initial IL-2 cycle. Subsequent IL-2 cycles were triggered by CD4 T cell counts less than 90% of baseline. Immune, metabolic, and quality of life indices were compared (Mann-Whitney and Fisher's exact tests), defining noninferiority as a percentage difference (C- I) in treatment success (CD4 T cells > or =90% of baseline at 6 months) with a 95% confidence interval (CI) lower limit greater than -20%.

RESULTS

Demographic and immune parameters were similar between the groups at baseline. Median CD4 T cell count, HIV viral load, and treatment success differed significantly at 6 months (I: 866 cells/microl, 39,389 copies/ml, 48.1%; C: 1246 cells/microl, <50 copies/ml, 92.3%; P < or = 0.001). Group I was inferior to C (% difference = -44.2%; 95% CI: -64.2%, -11.2%; P = 0.013). Minor statistically significant differences in HgbA1c and energy level occurred at 6 months (I > C). Following HAART interruption, single cases of acute retroviral syndrome, secondary syphilis, non-Hodgkin's lymphoma, and Kaposi's sarcoma recurrence were observed.

CONCLUSION

IL-2 alone was inferior to IL-2 with HAART in maintaining baseline CD4 T cell counts. HAART interruption had a small impact on metabolic parameters and quality of life.

Determination of the underlying cause of death in three multicenter international HIV clinical trials

PURPOSE

Describe processes and challenges for an Endpoint Review Committee (ERC) in determining and adjudicating underlying causes of death in HIV clinical trials.

METHOD

Three randomized HIV trials (two evaluating interleukin-2 and one treatment interruption) enrolled 11,593 persons from 36 countries during 1999-2008. Three ERC members independently reviewed each death report and supporting source documentation to assign underlying cause of death; differences of opinion were adjudicated.

RESULTS

Of 453 deaths reported through January 14, 2008, underlying causes were as follows: 10% AIDS-defining diseases, 21% non-AIDS malignancies, 9% cardiac diseases, 9% liver disease, 8% non-AIDS-defining infections, 5% suicides, 5% other traumatic events/accidents, 4% drug overdoses/acute intoxications, 11% other causes, and 18% unknown. Major reasons for unknown classification were inadequate clinical information or supporting documentation to determine cause of death. Half (51%) of deaths reviewed by the ERC required follow-up adjudication; consensus was eventually always reached.

CONCLUSION

ERCs can successfully provide blinded, independent, and systematic determinations of underlying cause of death in HIV clinical trials. Committees should include those familiar with AIDS and non-AIDS-defining diseases and have processes for adjudicating differences of opinion. Training for local investigators and procedure manuals should emphasize obtaining maximum possible documentation and follow-up information on all trial deaths.

Long-term clinical and surrogate marker effects of subcutaneous intermittent interleukin-2 without antiretroviral therapy in HIV-infected patients

OBJECTIVES

Subcutaneous administration of interleukin-2 (IL-2) has been shown to increase CD4 counts in HIV-infected patients. It remains unclear whether this effect is associated with a clinical benefit.

PATIENTS AND METHODS

We conducted a long-term follow-up in the cohort of the UK-Vanguard study in which three groups of 12 antiretroviral-naive subjects with CD4 cell counts >350 cells/mm(3) received no treatment or IL-2 at either 4.5 or 7.5 MIU twice daily in 5 day cycles, respectively.

RESULTS

Mean follow-up was 376 weeks. IL-2 therapy was associated with a higher area under the curve of CD4 cell count change from baseline at week 48 but not thereafter. HIV-RNA levels were unaffected. Highly active antiretroviral therapy (HAART) was initiated after a mean of 172, 175 and 152 weeks in the control group, low-dose and high-dose IL-2 treatment group, respectively, a statistically non-significant difference. There was a tendency to start HAART soon after discontinuation of IL-2 therapy which may have been triggered by the steep decay of CD4 counts. There were two serious adverse events in the control group, seven in the low-dose IL-2 group and eight in the high-dose IL-2 group. No pattern of disease was detected, making an association with IL-2 therapy unlikely.

CONCLUSIONS

We could detect neither a benefit of IL-2 therapy after week 48 nor delayed initiation of HAART. This is currently the longest follow-up data comparing IL-2 therapy with no therapy in antiretroviral-naive HIV-infected patients and does not show a persistent benefit of the intervention.

TILT: a randomized controlled trial of interruption of antiretroviral therapy with or without interleukin-2 in HIV-1 infected individuals

OBJECTIVE

We aimed to see if structured treatment interruption (STI) could be supported safely with the use of two cycles of IL-2 (4.5 MIU q12h subcutaneously 5 days) before STI to prolong the time before therapy restarted.

METHODS

Subjects were randomly allocated to either A - continuous ART; B - continue for 9 weeks, then STI; restart with the same ART when the CD4 count falls below 200 cells; or C - two cycles of IL-2, 8 weeks apart, while still on ART; at week 9 stop ART and use a new cycle of IL-2 alone whenever the CD4 count falls < 300 cells. Patients were followed until week 105.

RESULTS

86 mostly white middle aged homosexual men with a baseline median CD4 count of 754 cells/ml (range 240-1400) and a nadir CD4 count of 268 cells/ml (range 62-822) enrolled. By 96 weeks there was a 66% probability of having restarted ART in arm B compared with 34% in arm C (p = 0.002; log rank test). New drugs were used in 60% in arm A, 57% in arm B and 45% in arm C. 4 subjects had a dose modification in the first cycle due to toxicity with 2 interrupting. There were 39 SAEs with 21 in arm C. There were no deaths.

CONCLUSIONS

The primary aim of the trial was to gain experience in using IL-2. IL-2 delayed restarting drugs and fewer new drugs were used.

Predictors of CD4 count change over 8 months of follow up in HIV-1-infected patients with a CD4 count>or=300 cells/microL who were assigned to 7.5 MIU interleukin-2

BACKGROUND

ESPRIT is a randomized trial comparing the clinical impact of interleukin (IL)-2 plus antiretrovirals vs antiretrovirals alone. Identification of factors that influence the relationship between IL-2 and CD4 count recovery will enable better personalization of treatment with IL-2 in HIV-1-positive individuals. The IL-2 induction phase consists of three dosing cycles over 6-8 months (7.5 MIU twice a day, for 5 days every 8 weeks).

METHODS

We included patients initiating IL-2 at the 7.5 MIU dose with an 8-month CD4 count, measured at least 30 days after their last cycle. We identified baseline predictors of CD4 count changes over 8 months using linear regression.

RESULTS

Of 2090 patients assigned IL-2, 1673 (80%) were included in the analysis. The median (interquartile range) baseline CD4 count was 461 (370, 587) cells/microL with a median increase of 233 (90, 411) cells/microL at month 8. After adjustments, significant predictors of CD4 count change included CD4 nadir (29.8 cells/microL greater increase per 100 cells/microL higher; P<0.0001), last CD4 count before baseline (mean 36.0 cells/microL greater increase per 100 cells/microL higher; P<0.0001), time from antiretroviral start to baseline (8.3 cells/microL smaller increase per year longer; P=0.001), age (11.7 cells/microL smaller increase per 5 years older; P=0.005) and race (79.7 cells/microL greater increase for black patients vs white patients; P=0.003). A linear relationship existed between total IL-2 dose in the first cycle and CD4 count change (73.1 cells/microL greater increase per 15 MIU higher; P<0.0001).

CONCLUSIONS

Prior nadir and current CD4 counts, age and IL-2 dose are major determinants of CD4 increases induced by with intermittent administration of IL-2 in HIV-1-positive individuals on antiretrovirals. The clinical function of these induced CD4 cells is under study.

Long-term effects of intermittent interleukin-2 therapy in chronic HIV-infected patients (ANRS 048-079 Trials)

OBJECTIVE

Interleukin (IL)-2 therapy leads to significant CD4 cell increases in HIV-infected patients. Since phase III trials are ongoing, studies supporting the long-term feasibility of this strategy are needed.

METHODS

We studied the long-term outcomes of 131 patients treated with IL-2 in two studies initiated either before (ANRS 048) or following (ANRS 079) the advent of HAART.

RESULTS

At the last assessment (median follow-up 3.4 years), these patients experienced a gain of 428 cells/microl and a decrease in plasma HIV RNA to 1.70 log10 copies/ml. In both studies, high CD4 cell counts were maintained with a median of ten 5-day cycles of subcutaneous IL-2. Median time since the last cycle was 2 years. At last assessment, 59% of 048 patients maintained a non-HAART regimen. Detailed analysis at week 170 showed that median CD4 cell counts were 856 (048) and 964 (079) cells/microl. This corresponded to a gain from baseline of 515 (048) and 627 (079) cells/microl. The median viral load decreases from baseline and corresponded to 1.70 (048) and 1.88 (079) log10 copies/ml. Comparisons across the studies showed that CD4 gains and viral load changes were similar whether HAART or non-HAART was used. The frequency of cycling, but not CD4 cell counts, viral loads or antiviral regimen at baseline, was predictive of long-term CD4 gain (P = 0.03).

CONCLUSION

Altogether, these observations support IL-2 as a long-term therapeutic strategy in HIV infection.

The feasibility of clinical endpoint trials in HIV infection in the highly active antiretroviral treatment (HAART) era

BACKGROUND

Planning clinical-endpoint trials in patients with HIV remain difficult as long-term follow-up of many patients is required. Cohort studies of patients with HIV can provide key estimates of the likely disease progression, required sample size and follow-up.

OBJECTIVES

To verify the assumptions used in designing ESPRIT, a large randomized clinical trial assessing the clinical benefit of interleukin-2 treatment in patients with HIV infection, to use EuroSIDA to mimic the inclusion criterion of ESPRIT in order to compare the observed event rate in ESPRIT with the projected rate in EuroSIDA, and to project the required length of ESPRIT.

METHODS

Patients in EuroSIDA who satisfied the ESPRIT recruitment criteria were selected. Patients were followed from baseline to new AIDS or death.

RESULTS

The incidence of clinical progression in the selected EuroSIDA patients (N = 4482) was 1.5 per 100 PYFU (95% CI 1.3-1.7), and did not increase with increasing time from baseline, contrary to what was assumed in the design of the ESPRIT trial. In ESPRIT (N = 4150), for which the comparative data remain blinded, the incidence was 1.1 per 100 PYFU (95% CI 0.9-1.3), with no increase over time. The average follow-up required to complete ESPRIT and accrue the 320 events required by protocol would be seven years, 10 months using the projected rates from the EuroSIDA study, and seven years, 11 months if the observed event rate in ESPRIT continued unchanged.

LIMITATIONS

Differences between patients recruited to observational studies or clinical trials cannot always be adjusted for.

CONCLUSIONS

Event rates in EuroSIDA were similar in the first two years to those used in the design of ESPRIT, but did not increase over time, leading to an increase in the expected duration of ESPRIT. Clinical endpoint trials in HIV infection remain feasible, and large cohort studies are critical to the planning and ongoing assessment of design assumptions in such trials. The underlying assumptions of the clinical trial should be re-examined to ensure the original trial assumptions remain valid.

Interleukin-2: a potential treatment option for postherpetic neuralgia?

Postherpetic neuralgia is a chronic pain syndrome that is often difficult to treat and can lead to a disabling disease if it is resistant to therapy. Presented here is the case of a 46-year-old patient with human immunodeficiency virus infection and chronic, treatment-resistant neuralgia. Postherpetic pain resolved after treatment with 1 cycle of subcutaneous recombinant interleukin-2.

Post-trial access to tested interventions: the views of IRB/REC chair, investigators, and research participants in a multinational HIV/AIDS study

Controversy exists regarding an ethical requirement to make products proven effective in research available after the trial. Little is known about the views of several stakeholders. Phone or self-administered questionnaires were completed by 65 IRB/REC chairs, 117 investigators, and 500 research participants in a multinational HIV trial to assess their views about posttrial access to interventions proven effective in the study. A total of 83% of research participants, 29% of IRB/REC chairs, and 42% of researchers (p = 0.046) thought IL-2 should be guaranteed for every HIV-infected person in the world if proven effective. Most European and Latin American research participants thought IL-2 should be provided free, while North American, Australian, and Thai participants commonly said at a price the average person could afford (p < 0.001). Most IRB/REC chairs and researchers thought the CIOMS "reasonable availability" requirement applied to people in the country where the study was conducted and meant a drug should be available at a price the average person could afford and that host country governments had primary responsibility for making it available. Most research participants believe an HIV drug proven effective in research should be made available to everyone in the world who needs it. IRB/REC chairs and researchers were less expansive both in who and how they thought a drug should be guaranteed.

A randomised trial of subcutaneous intermittent interleukin-2 without antiretroviral therapy in HIV-infected patients: the UK-Vanguard Study

Objective:

The objective of the trial was to evaluate in a pilot setting the safety and efficacy of interleukin-2 (IL-2) therapy when used without concomitant antiretroviral therapy as a treatment for HIV infection.

Design and Setting:

This was a multicentre randomised three-arm trial conducted between September 1998 and March 2001 at three clinical centres in the United Kingdom.

Participants:

Participants were 36 antiretroviral treatment naïve HIV-1-infected patients with baseline CD4 T lymphocyte counts of at least 350 cells/mm³.

Interventions:

Participants were randomly assigned to receive IL-2 at 15 million international units (MIU) per day (12 participants) or 9 MIU/day (12 participants) or no treatment (12 participants). IL-2 was administered by twice-daily subcutaneous injections for five consecutive days every 8 wk.

Outcome Measures:

Primary outcome was the change from baseline CD4 T lymphocyte count at 24 wk. Safety and plasma HIV RNA levels were also monitored every 4 wk through 24 wk. The two IL-2 dose groups were combined for the primary analysis.

Results:

Area under curve (AUC) for change in the mean CD4 T lymphocyte count through 24 wk was 129 cells/mm³ for those assigned IL-2 (both dose groups combined) and 13 cells/mm³ for control participants (95% CI for difference, 51.3–181.2 cells/mm³; p = 0.0009). Compared to the control group, significant increases in CD4 cell count were observed for both IL-2 dose groups: 104.2/mm³ (p = 0.008) and 128.4 cells/mm³ (p = 0.002) for the 4.5 and 7.5 MIU dose groups, respectively. There were no significant differences between the IL-2 (0.13 log₁₀ copies/ml) and control (0.09 log₁₀ copies/ml) groups for AUC of change in plasma HIV RNA over the 24-wk period of follow-up (95% CI for difference, −0.17 to 0.26; p = 0.70). Grade 4 and dose-limiting side effects were in keeping with those previously reported for IL-2 therapy.

Conclusions:

In participants with HIV infection and baseline CD4 T lymphocyte counts of at least 350 cells/mm³, intermittent subcutaneous IL-2 without concomitant antiretroviral therapy was well tolerated and produced significant increases in CD4 T lymphocyte counts and did not adversely affect plasma HIV RNA levels.

Background: There is very good trial evidence that combinations of antiretroviral drugs improve the prognosis of people with HIV infection. However, these drugs can have major side effects, and HIV can become resistant to them. The development of alternative treatments might allow antiretroviral use to be delayed in some people, thereby reducing toxicity and the emergence of resistant strains of HIV.

What this trial shows: The researchers studied 36 adult patients in the United Kingdom who were infected with HIV and who had not previously been prescribed antiretrovirals. Participants in the trial were given either one of two different dosage levels of IL-2 (a chemical messenger normally produced in the body by particular immune cells) by injection under the skin or no treatment at all. Patients given IL-2 at either dosage experienced an increase in levels of CD4 T lymphocytes, the type of immune cell depleted by HIV infection, as compared to patients receiving no treatment. The viral load in patients receiving IL-2 did not differ from that of patients in the control arm.

Strengths and limitations: The rationale for this trial—to delay administration of antiretroviral drugs—is sound, as is the experimental design. The results are limited, however, by the short follow-up of patients in the trial and by the lack of clinical endpoints (such as disease progression), so it is not possible to tell whether patients in the trial benefited directly from the IL-2 treatment.

Contribution to the evidence: The clinical effectiveness and safety of IL-2 together with antiretrovirals as a treatment for HIV infection is currently being evaluated in other, large-scale trials. To date, no other study has assessed the outcomes arising from administration of IL-2 alone. Data from the current trial will be useful in planning further research to examine whether IL-2 might help delay antiretrovirals in HIV-positive people.

Immunological recovery and antiretroviral therapy in HIV-1 infection

Potent antiretroviral therapy has dramatically improved the prognosis of patients infected with HIV-1. Primary and secondary prophylaxis against Pneumocystis carinii, Mycobacterium avium, cytomegalovirus, and other pathogens can be discontinued safely once CD4 cell counts have increased beyond pathogen-specific thresholds. Approximately one-third of individuals receiving antiretroviral therapy will not reach CD4 cell counts above 500 cells per muL after 5 years despite continuous suppression of plasma HIV-1 RNA. Whether this failure represents a risk factor for the long-term incidence of opportunistic diseases--eg, tuberculosis or malignancies--remains uncertain. We describe the time course of CD4 cell concentrations in patients whose plasma HIV-1 RNA is durably suppressed by antiretroviral therapy, in patients with incomplete suppression of plasma HIV-1 RNA, and during treatment interruptions. In addition, immune reconstitution disease, an inflammatory syndrome associated with immunological recovery occurring days to weeks after the start of antiretroviral therapy, is briefly described.

Reduced Secondary Cytokine Induction by BAY 50-4798, a High-Affinity Receptor-Specific Interleukin-2 Analog

Recombinant interleukin-2 (IL-2) (aldesleukin, Proleukin, Chiron, Emeryville, CA) is approved for treatment of cancer patients and under investigation in HIV-infected individuals. However, treatment with aldesleukin is associated with toxicity, which may be due to its elicitation of inflammatory mediators from cells that express the intermediate-affinity IL-2 receptor. BAY 50-4798, a novel IL-2 analog, is a selective agonist for the high-affinity receptor. It induces the proliferation of activated T cells with a potency similar to that of aldesleukin but has reduced activity on cells expressing the intermediate-affinity receptor. In the current study, we compared cytokine responses elicited in peripheral blood mononuclear cell (PBMC) cultures stimulated with BAY 50-4798 or aldesleukin. BAY 50-4798 induced approximately 5-fold lower mean levels of endogenous IL-2 than aldesleukin, and at least 50% lower levels of proinflammatory cytokines, such as tumor necrosis fctor-alpha (TNF-alpha), IL-1beta, IL-6, and interferon-gamma (IFN-gamma). Furthermore, statistically significant reductions in the levels of IL-5, IL-8, IL-10, IL-13, and granulocyte-macrophage colony-stimulating factor (GM-CSF) were observed in response to BAY 50-4798. These findings increase our understanding of the biologic action of BAY 50-4798 and suggest a mechanism by which it may exhibit better safety than aldesleukin in humans.

Interruption of antiretroviral therapy blunts but does not abrogate CD4 T-cell responses to interleukin-2 administration in HIV infected patients

BACKGROUND

Intermittent administration of interleukin (IL)-2 to HIV infected patients leads to CD4 T-cell expansions that are associated with decreased CD4 T-cell turnover. IL-2 is under evaluation in antiretroviral therapy (ART) interruption studies, but it is unclear how the emergence of viremia may affect CD4 expansions.

METHODS

CD4 T-cell responses were evaluated in 27 HIV infected patients on long-term intermittent IL-2 therapy who underwent ART interruption immediately after an IL-2 cycle ('IL-2/off') and compared with responses from a previous IL-2 cycle while on continuous ART ('IL-2/on'). Immunophenotypic analysis, including intracellular Ki67 staining, of cryopreserved peripheral blood mononuclear cells was performed.

RESULTS

CD4 T-cell increases, in naive and central memory CD4 T-cell subsets, were observed in the IL-2/on (106 and 327 cells/microl, respectively) and IL-2/off (84 and 184 cells/microl, respectively) cycles 1 month following IL-2 administration. These increases were greater during the IL-2/on cycle (P = 0.05, P = 0.01, respectively). In both cycles, the change in CD4 T-cell count correlated with the change in CD4/CD25 T cells. In the IL-2/off cycle, the change in the proportion of CD4 T cells expressing Ki67 was associated with both the changes in viral load (r = 0.64, P = 0.001) and the changes in CD4 T cells (r = -0.56, P = 0.01).

CONCLUSIONS

IL-2 administration followed by ART interruption led to significant, although blunted, CD4 T-cell increases. IL-2 induced CD4 T-cell increases in the setting of emergent viremia were associated with decreased CD4 T-cell activation that counteracted the viremia-induced increases in CD4 T-cell activation.

Study conduct, monitoring and data management in a trinational trial: the OPTIMA model

The OPTions In Management with Antiretrovirals (OPTIMA) Trial, a collaboration between three governmental agencies in the USA, UK and Canada is a large-scale, multicenter, randomized controlled trial designed to compare the relative efficacy of different therapeutic strategies in HIV disease. The collaboration of three coordinating centers introduced unique data management issues including: a) use of different data systems for managing "country" trial data; b) two-way data transfer between the coordinating centers and the center where OPTIMA data is merged and analysis files are generated; and c) translation of certain data forms (mainly patient completed questionnaires) into French and Spanish. The involvement of three data centers provided a challenge in planning, designing and executing data management procedures in OPTIMA. Processes were implemented to ensure the trial's successful execution at the trinational level, without disregarding country-specific requirements and regulations. The OPTIMA model required a significant time and resource investment on behalf of all agencies involved, but allowed for autonomy and a sense of joint ownership of data in different countries.

Induction of prolonged survival of CD4+ T lymphocytes by intermittent IL-2 therapy in HIV-infected patients

HIV infection leads to decreases in the number of CD4 T lymphocytes and an increased risk for opportunistic infections and neoplasms. The administration of intermittent cycles of IL-2 to HIV-infected patients can lead to profound increases (often greater than 100%) in CD4 cell number and percentage. Using in vivo labeling with 2H-glucose and BrdU, we have been able to demonstrate that, although therapy with IL-2 leads to high levels of proliferation of CD4 as well as CD8 lymphocytes, it is a remarkable preferential increase in survival of CD4 cells (with half-lives that can exceed 3 years) that is critical to the sustained expansion of these cells. This increased survival was time-dependent: the median half-life, as determined by semiempirical modeling, of labeled CD4 cells in 6 patients increased from 1.7 weeks following an early IL-2 cycle to 28.7 weeks following a later cycle, while CD8 cells showed no change in the median half-life. Examination of lymphocyte subsets demonstrated that phenotypically naive (CD27+CD45RO-) as well as central memory (CD27+CD45RO+) CD4 cells were preferentially expanded, suggesting that IL-2 can help maintain cells important for host defense against new antigens as well as for long-term memory to opportunistic pathogens.

In vivo expansion of CD4CD45RO-CD25 T cells expressing foxP3 in IL-2-treated HIV-infected patients

Administration of IL-2 to HIV-infected patients leads to expansion of a unique subset of CD4CD45ROCD25 cells. In this study, the origin, clonality, and function of these cells were investigated. Analysis of TCR excision circles revealed that the CD4CD45ROCD25 cells were the product of peripheral expansion but remained polyclonal as determined by TCR repertoire analysis. Phenotypically, these cells were distinct from naturally occurring Tregs; they exhibited intermediate features, between those of memory and naive cells, and had lower susceptibility to apoptosis than CD45ROCD25 or memory T cells. Studies of intracellular cytokine production and proliferation revealed that cytokine-expanded naive CD25 cells had low IL-2 production and required costimulation for proliferation. Despite elevated expression of forkhead transcription factor P3 (foxP3), they exerted only weak suppression compared with CD45ROCD25 cells (Tregs). In summary, in vivo IL-2 administration to HIV-infected patients leads to peripheral expansion of a population of long-lived CD4CD45ROCD25 cells that express high levels of foxP3 but exert weak suppressive function. These CD4CD25 cytokine-expanded naive cells, distinct from antigen-triggered cells and Tregs, play a role in the maintenance of a state of low turnover and sustained expansion of the CD4 T cell pool.

Effect of IL-2 on hepatitis C virus RNA levels in patients co-infected with human immunodeficiency virus receiving HAART

The effect of interleukin-2 (IL-2) on the plasma levels of hepatitis C RNA (HCV-RNA) has varied in published reports. We measured the impact of IL-2 on plasma HCV RNA levels in 54 human immunodeficiency virus (HIV)/HCV coinfected patients enrolled in a randomized trial of 512 participants designed to compare the virologic and immunologic effects of cycled IL-2 plus antiretroviral therapy (ART) vs ART alone in the treatment of HIV in patients with CD4 cell counts > or =300 cells/mm(3). The mean decreases in average HCV RNA levels (copies/mL, log (10)) were 0.28 log in the IL-2 group (n = 26) and 0.04 log in the ART alone group (n = 28) at 12 months (P = 0.18). The changes in HCV RNA level were not associated with baseline or nadir CD4 cell counts, baseline aspartate aminotransferanse, CD4 cell response to IL-2, or changes in plasma HIV RNA values. Compared with those participants who only had HIV, the HIV/HCV co-infected patients did not have a significantly different CD4 cell response to IL-2 therapy. Intermittent IL-2 therapy does not produce a significant sustained decrease in plasma HCV RNA levels among patients co-infected with HIV/HCV who are on highly active ART.

HIV disease progression in a patient cohort treated via a clinical research network in a resource limited setting

OBJECTIVE

To examine HIV disease progression in a cohort of adult patients treated with antiretroviral therapy (ART) via a clinical research network in Thailand.

DESIGN, SETTING, PARTICIPANTS AND INTERVENTION

A cohort of 417 patients enrolled in a series of randomized ART trials, between 1996 and December 2002.

MAIN OUTCOME MEASURES

Progression to combined endpoint of AIDS defining illness or death according to baseline characteristics, ART used, immunological and virological responses to initial 6 months of ART.

RESULTS

During 1677 person years of follow-up, 29 of 417 patients progressed; tuberculosis was the most common event defining progression (14 of 29 events). The rates of progression to combined endpoint or death alone were 1.7 [95% confidence interval (CI), 1.1-2.4] and 0.7 (95% CI, 0.3-1.3) per 10 person years respectively. Compared to patients with baseline CD4 cell counts > or =350 x 10/l, the adjusted hazard ratio (HR) for progression was 3.67 (95% CI, 1.31-10.27) for patients with <200 x 10 cells/l. Responses to 6 months of therapy were the strongest predictors of disease progression; compared to patients with undetectable viral load at 6 months, HR for progression was 4.95 (95% CI, 2.14-11.46) for viral load >4 log10. Compared to patients with a 6-month CD4 cell count > or =350 x 10/l, HR for progression was 5.22 (95% CI, 1.90-14.37) for patients with <200 x 10 cells/l.

CONCLUSIONS

HIV-infected patients in Thailand who had access to ART, appropriate care, CD4 cell and viral load monitoring facilities via a clinical research network had progression rates comparable to those in developed countries. In this setting, ART initiation could generally be delayed until the CD4 cell count approaches 200 x 10/l.

Graves' disease after interleukin-2 therapy in a patient with human immunodeficiency virus infection

Interleukin-2 (IL-2) is a cytokine that regulates the proliferation and differentiation of lymphocytes, and is currently used clinically in the treatment of assorted malignancies. Additionally, IL-2 is being actively investigated in clinical trials for treatment of human immunodeficiency virus (HIV) infection. Patients treated with IL-2 are susceptible to autoimmune thyroid disease (AITD), presenting as thyroiditis, which leads to either thyrotoxicosis or hypothyroidism, if not correctly and promptly identified and treated. IL-2-induced hypothyroidism can also sometimes follow a thyrotoxic phase. However, the development of Graves' disease (GD) in this clinical setting has not been reported to date. Here, we report the case of a 39-year-old HIV-infected man in whom GD developed after IL-2 therapy. We correlated the immunologic parameters pertinent to the patient's HIV infection status with clinical, hormonal, and serologic evidence of GD during its emergence. This revealed an association between peripheral blood cell numbers of specific lymphocyte subpopulations (CD4(+), CD3(+)CD25(+), and naïve T-cells) and serum levels of markers for AITD (free thyroxine [T(4)] and thyroid-stimulating immunoglobulin). Interestingly, no association was found between natural killer (NK) cell numbers and AITD markers. The immunopathogenesis of GD in this patient may be similar to that hypothesized for the GD that occurs in immune-reconstituted patients after combination antiretroviral therapy. From a practical standpoint, we propose that patients who have received or are receiving treatment with IL-2 who show signs of hyperthyroidism need to be carefully evaluated for GD.

IL-2–induced CD4+ T-cell expansion in HIV-infected patients is associated with long-term decreases in T-cell proliferation

Administration of interleukin 2 (IL-2) leads to selective and sustained CD4+ T-cell expansions in patients infected with HIV. It has been hypothesized that persistent CD4+ T-cell proliferation is the primary mechanism maintaining these expansions. T-cell proliferation was studied by ex vivo bromodeoxyuridine (BrdU) incorporation and intracellular Ki67 staining in HIV-infected patients treated with antiretroviral therapy (ART) with or without IL-2. In contrast to the tested hypothesis, HIV-infected patients treated with IL-2 had lower CD4+ T-cell proliferation compared to patients treated with ART alone. Independently of viral load changes, administration of IL-2 led to a decrease in basal CD4+ T-cell proliferation. Total numbers of CD4+ T cells with naive and recall, but not effector, memory phenotype were increased. The degree of CD4+ T-cell expansion correlated with the decreases in proliferation and a strong association was seen between these decreases and the expansion of the CD4+/CD25+ subset. Intermittent IL-2 in HIV-infected patients leads to expansions of CD4+/CD25+ T cells with naive and recall memory phenotypes that strongly correlate with decreases in proliferation. These data suggest that decreased T-cell proliferation is central in the CD4+ T-cell expansions induced by IL-2.

CD4 cell response to 3 doses of subcutaneous interleukin 2: meta-analysis of 3 Vanguard studies

BACKGROUND

In advance of a large clinical end point trial evaluating the effectiveness of subcutaneous interleukin 2 (scIL-2) for treatment of patients with human immunodeficiency virus (HIV) infection, 3 identically designed Vanguard trials were conducted in Buenos Aires, Argentina; Bangkok, Thailand; and Houston, Texas. To more precisely quantitate the effect on CD4 cell response of 3 different doses of scIL-2 that were administered twice daily for 5 days every 8 weeks, the results of these 3 trials were pooled in a meta-analysis.

METHODS

Two hundred eighteen HIV-1-infected subjects who were receiving antiretroviral therapy and who had a baseline CD4 cell count of > or =350 cells/mm3 were consecutively randomized to receive scIL-2 at a dose of 1.5 mIU (n=36) or a control regimen (n=36); or scIL-2 at a dose of 4.5 mIU (n=36) or a control regimen (n=36); or scIL-2 at a dose of 7.5 mIU (n=37) or a control regimen (n=37). After completion of 3 cycles of therapy, the subjects were enrolled in an extension phase (months 6-12). Subjects were encouraged to receive additional cycles of scIL-2 to maintain a CD4 cell count of more than twice the baseline count or >1000 cells/mm3.

RESULTS

After completion of 3 cycles of scIL-2, the mean CD4 cell count changes from baseline (calculated as changes from baseline in a scIL-2 group minus changes from baseline in its contemporaneous control group) were 67 (P=.14), 339 (P<.0001), and 605 cells/mm3 (P<.0001) for the 1.5, 4.5, and 7.5 mIU dose groups, respectively (P<.0001 for differences among dose groups). Between months 6 and 12, a total of 78%, 39%, and 32% of subjects assigned to the 1.5, 4.5, and 7.5 mIU dose groups, respectively, needed at least 1 additional cycle to achieve the CD4 cell count goal. At 12 months, the differences in the mean change in CD4 cell count from baseline between each scIL-2 dose group and its contemporaneous control group were 184, 369, and 432 cells/mm3, respectively (P=.01 for differences among dose groups).

CONCLUSIONS

Although CD4 cell count increases were seen in all 3 dose groups, higher scIL-2 doses resulted in greater CD4 cell count changes after 6 months, compared with control groups.