Tenofovir Use is associated with a Reduction in Calculated Glomerular Filtration Rates in the Swiss HIV Cohort Study

Background

A growing number of case reports have described tenofovir (TDF)-related proximal renal tubulopathy and impaired calculated glomerular filtration rates (cGFR). We assessed TDF-associated changes in cGFR in a large observational HIV cohort.

Methods

We compared treatment-naive patients or patients with treatment interruptions ≥12 months starting either a TDF-based combination antiretroviral therapy (cART) ( n=363) or a TDF-sparing regime ( n=715). The predefined primary endpoint was the time to a 10 ml/min reduction in cGFR, based on the Cockcroft-Gault equation, confirmed by a follow-up measurement at least 1 month later. In sensitivity analyses, secondary endpoints including calculations based on the modified diet in renal disease (MDRD) formula were considered. Endpoints were modelled using pre-specified covariates in a multiple Cox proportional hazards model.

Results

Two-year event-free probabilities were 0.65 (95% confidence interval [CI] 0.58–0.72) and 0.80 (95% CI 0.76–0.83) for patients starting TDF-containing or TDF-sparing cART, respectively. In the multiple Cox model, diabetes mellitus (hazard ratio [HR]=2.34 [95% CI 1.24–4.42]), higher baseline cGFR (HR=1.03 [95% CI 1.02–1.04] by 10 ml/min), TDF use (HR=1.84 [95% CI 1.35–2.51]) and boosted protease inhibitor use (HR=1.71 [95% CI 1.30–2.24]) significantly increased the risk for reaching the primary endpoint. Sensitivity analyses showed high consistency.

Conclusion

There is consistent evidence for a significant reduction in cGFR associated with TDF use in HIV-infected patients. Our findings call for a strict monitoring of renal function in long-term TDF users with tests that distinguish between glomerular dysfunction and proximal renal tubulopathy, a known adverse effect of TDF.

Adverse Events to Antiretrovirals in the Swiss HIV Cohort Study: Effect on Mortality and Treatment Modification

Background

Antiretroviral therapy (ART) decreases morbidity and mortality in HIV-infected patients but is associated with considerable adverse events (AEs).

Methods

We examined the effect of AEs to ART on mortality, treatment modifications and drop-out in the Swiss HIV Cohort Study. A cross-sectional evaluation of prevalence of 13 clinical and 11 laboratory parameters was performed in 1999 in 1,078 patients on ART. AEs were defined as abnormalities probably or certainly related to ART. A score including the number and severity of AEs was defined. The subsequent progression to death, drop-out and treatment modification due to intolerance were evaluated according to the baseline AE score and characteristics of individual AEs.

Results

Of the 1,078 patients, laboratory AEs were reported in 23% and clinical AEs in 45%. During a median follow up of 5.9 years, laboratory AEs were associated with higher mortality with an adjusted hazard ratio (HR) of 1.3 (95% confidence interval [CI] 1.2–1.5; P<0.001) per score point. For clinical AEs no significant association with increased mortality was found. In contrast, an increasing score for clinical AEs (HR 1.11, 95% CI 1.04–1.18; P=0.002), but not for laboratory AEs (HR 1.07, 95% CI 0.97–1.17; P=0.17), was associated with antiretroviral treatment modification. AEs were not associated with a higher drop-out rate.

Conclusions

The burden of laboratory AEs to antiretroviral drugs is associated with a higher mortality. Physicians seem to change treatments to relieve clinical symptoms, while accepting laboratory AEs. Minimizing laboratory drug toxicity seems warranted and its influence on survival should be further evaluated.

Treatment and Prognosis of AIDS-Related Lymphoma in the Era of Highly Active Antiretroviral Therapy: Findings from the Swiss HIV Cohort Study

Objective

To assess the characteristics of combination antiretroviral therapy (cART) administered concomitantly with chemotherapy and to establish prognostic determinants of patients with AIDS-related non-Hodgkin's lymphoma.

Methods

The study included 91 patients with AIDS-related non-Hodgkin's lymphoma from the Swiss HIV Cohort Study enrolled between January 1997 and October 2003, excluding lymphomas of the brain. We extracted AIDS-related non-Hodgkin's lymphoma- and HIV-specific variables at the time of lymphoma diagnosis as well as treatment changes over time from charts and from the Swiss HIV Cohort Study database. Cox regression analyses were performed to study predictors of overall and progression-free survival.

Results

During a median follow up of 1.6 years, 57 patients died or progressed. Thirty-five patients stopped chemotherapy prematurely (before the sixth cycle) usually due to disease progression; these patients had a shorter median survival than those who completed six or more cycles (14 versus 28 months). Interruptions of cART decreased from 35% before chemotherapy to 5% during chemotherapy. Factors associated with overall survival were CD4+ T-cell count (<100 cells/μl) (hazard ratio [HR] 2.95 [95% confidence interval (CI) 1.53–5.67], hepatitis C seropositivity (HR 2.39 [95% CI 1.01–5.67]), the international prognostic index score (HR 1.98–3.62 across categories) and Burkitt histological subtypes (HR 2.56 [95% CI 1.13–5.78]).

Conclusions

Interruptions of cART were usually not induced by chemotherapy. The effect of cART interruptions on AIDS-related non-Hodgkin's lymphoma prognosis remains unclear, however, hepatitis C seropositivity emerged as a predictor of death beyond the well-known international prognostic index score and CD4+ T-cell count.

CD4+ T-Cell Count Increase in HIV-1-Infected Patients with Suppressed Viral Load Within 1 year after start of antiretroviral therapy

Background

CD4+ T-cell recovery in patients with continuous suppression of plasma HIV-1 viral load (VL) is highly variable. This study aimed to identify predictive factors for long-term CD4+ T-cell increase in treatment-naive patients starting combination antiretroviral therapy (cART).

Methods

Treatment-naive patients in the Swiss HIV Cohort Study reaching two VL measurements <50 copies/ml >3 months apart during the 1st year of cART were included ( n=1,816 patients). We studied CD4+ T-cell dynamics until the end of suppression or up to 5 years, subdivided into three periods: 1st year, years 2–3 and years 4–5 of suppression. Multiple median regression adjusted for repeated CD4+T-cell measurements was used to study the dependence of CD4+ T-cell slopes on clinical covariates and drug classes.

Results

Median CD4+ T-cell increases following VL suppression were 87, 52 and 19 cells/μl per year in the three periods. In the multiple regression model, median CD4+ T-cell increases over all three periods were significantly higher for female gender, lower age, higher VL at cART start, CD4+ T-cell <650 cells/μ l at start of the period and low CD4+ T-cell increase in the previous period. Patients on tenofovir showed significantly lower CD4+T-cell increases compared with stavudine.

Conclusions

In our observational study, long-term CD4+ T-cell increase in drug-naive patients with suppressed VL was higher in regimens without tenofovir. The clinical relevance of these findings must be confirmed in, ideally, clinical trials or large, collaborative cohort projects but could influence treatment of older patients and those starting cART at low CD4+ T-cell levels.

A Smoking Cessation Programme in HIV-Infected Individuals: A Pilot Study

Background

Antiretroviral therapy (ART) is a risk factor for cardiovascular disease (CVD) and smoking the most important modifiable cardiovascular risk factor.

Methods

We prospectively evaluated a smoking cessation programme (SCP) in HIV-infected individuals (intervention: counselling and nicotine replacement therapy). Primary endpoint was the smoking cessation rate at 12 months; secondary endpoints were CVD morbidity and mortality. Controls were a not randomized control group of smokers not participating in the SCP.

Results

Four-hundred and seventeen of 680 (61%) patients were smokers, and 34 of these participated in the SCP. Of these 34 individuals, 82% were male, the median age was 43 years, prior AIDS was recorded in 29%, and depressive disorder was recorded in 18%. Twenty-five (74%) patients were receiving ART. Additional risk factors were dyslipidaemia (68%), a prior cardiovascular event (24%), hypertension (15%), and a family history of CVD in 2/34 (6%) individuals. According to the Framingham equation, the 10-year risk of CVD was higher in SCP participants than in controls (11.2% versus 8.5%, P=0.06). At termination of the SCP, 17/34 (50%) individuals had stopped smoking compared with 57/383 (15%) controls. Self-reported smoking abstinence for ≥12 months was 13/34 (38%) in the intervention group and 27/383 (7%) in the control group (odds ration 6.2, 95% confidence interval 2.8–14.3). During the follow-up, two SCP participants and 4 controls experienced a myocardial infarction. One patient in the control group died of CVD.

Conclusions

SCP in HIV-infected individuals is feasible and should be encouraged. The long-term impact of smoking cessation on CVD morbidity and mortality should be evaluated in comparative trials.

A Longitudinal Analysis of Healthcare Costs after Treatment Optimization following Genotypic Antiretroviral Resistance Testing: Does Resistance Testing pay off?

Objective

To assess the impact of antiretroviral therapy optimized by genotypic antiretroviral resistance testing (GRT) on healthcare costs over a 2-year period in patients after antiretroviral treatment failure.

Study design

Non-randomized, prospective, tertiary care, clinic-based study.

Patients

One-hundred and forty-two HIV patients enrolled in the ‘ZIEL’ study and the Swiss HIV Cohort Study who experienced virological treatment failure.

Methods

For all patients GRT was used to optimize the antiretroviral treatment regimen. All healthcare costs during 2 years following GRT were assessed using micro-costing. Costs were separated into ART medication costs and healthcare costs other than ART medication (that is, non-ART medication costs, in-patient costs and ambulatory [out-patient] costs). These cost estimates were then split into four consecutive 6-month periods (period 1–4) and the accumulated cost for each period was calculated. Univariate and multivariate regression modelling techniques for repeated measurements were applied to assess the changes of healthcare costs over time and factors associated with healthcare costs following GRT.

Results

Overall healthcare costs after GRT decreased over time and were significantly higher in period 1 (32%; 95% confidence interval [CI]: 18–47) compared with period 4. ART medication costs significantly increased by 1,017 (95% CI: 22–2,014) Swiss francs (CHF) from period 1–4, whereas healthcare costs other than ART medication costs decreased substantially by a factor of 3.1 (95% CI: 2.6–3.7) from period 1 to period 4. Factors mostly influencing healthcare costs following GRT were AIDS status, costs being 15% (95% CI: 6–24) higher in patients with AIDS compared with patients without AIDS, and baseline viral load, costs being 12% (95% CI: 6–17) higher in patients with each log increase in plasma RNA.

Conclusions

Optimized antiretroviral treatment regimens following GRT lead to a reduction of healthcare costs in patients with treatment failure over 2 years. Patients in a worse health state (that is, a positive AIDS status and high baseline viral load) will experience higher overall costs.

Lipid Profiles for Antiretroviral-Naive Patients Starting Pi- and Nnrti-Based Therapy in the Swiss HIV Cohort Study

Background

Blood lipid abnormalities in patients on highly active antiretroviral therapy (HAART) have been associated with exposure to protease inhibitors (PIs), particularly ritonavir. First therapy with a non-nucleoside reverse transcriptase inhibitor (NNRTI) leads to relatively favourable lipid profiles. We report on medium-term lipid profiles (up to 5 years) for antiretroviral-naive patients starting NNRTI- and PI-based HAART in the Swiss HIV Cohort Study.

Methods

Since April 2000, blood samples taken at visits scheduled every 6 months have been analysed for cholesterol and triglyceride concentrations. For 1065 antiretroviral-naive patients starting HAART after April 2000, we estimated changes in concentration over time using multivariate linear regression with adjustment for baseline covariates, use of lipid-lowering drugs and whether the sample was taken in a fasting state.

Results

Non-high density lipoprotein (HDL) cholesterol levels increase with increasing exposure to either PI- or NNRTI-based therapy, HDL cholesterol levels increase and triglyceride levels decrease with increasing exposure to NNRTI-based therapy, whereas triglyceride levels increase with increasing exposure to PI-based therapy. Between NNRTI-based therapies, there is a slight difference in triglyceride levels, which tend to increase with increasing exposure to efavirenz and to decrease with increasing exposure to nevirapine. Of the three common PI-based therapies, nelfinavir appears to have a relatively favourable lipid profile, with little change with increasing exposure. Of the other two PI therapies, lopinavir with ritonavir has a more favourable profile than indinavir with ritonavir, with smaller increases in both non-HDL cholesterol and triglycerides and an increase in HDL cholesterol. Increasing exposure to abacavir is associated with a decrease in the level of triglycerides.

Conclusion

In general, NNRTI-based therapy is associated with a more favourable lipid profile than PI-based therapy, but different PI-based therapies are associated with very different lipid profiles. Nelfinavir appears to have a relatively favourable lipid profile. Of the two boosted PI therapies, lopinavir appears to have a more favourable lipid profile than indinavir.

Body Fat Changes among Antiretroviral-Naive Patients on Pi- and Nnrti-Based Haart in the Swiss HIV Cohort Study

Background

Body fat changes are common in patients with HIV. For patients on protease inhibitor (PI)-based highly active antiretroviral therapy (HAART), these changes have been associated with increasing exposure to therapy in general and to stavudine in particular. Our objective is to show whether such associations are more or less likely for patients on non-nucleoside reverse transcriptase inhibitor (NNRTI)-based HAART.

Methods

We included all antiretroviral-naive patients in the Swiss HIV Cohort Study starting HAART after April 2000 who had had body weight, CD4 cell count and plasma HIV RNA measured between 6 months before and 3 months after starting HAART, and at least one assessment of body fat changes after starting HAART. At visits scheduled every 6 months, fat loss or fat gain is reported by agreement between patient and physician. We estimate the association between reported body fat changes and both time on therapy and time on stavudine, using conditional logistical regression.

Results

Body fat changes were reported for 85 (9%) out of 925 patients at their first assessment; a further 165 had only one assessment. Of the remaining 675 patients, body fat changes were reported for 156 patients at a rate of 13.2 changes per 100 patient-years. Body fat changes are more likely with increasing age [odds ratio (OR) 1.18 (1.00–1.38) per 10 years], with increasing BMI [OR 1.06 (1.01–1.11)] and in those with a lower baseline CD4 cell count [OR 0.91 (0.83–1.01) per 100 cells/μl]. There is only weak evidence that body fat changes are more likely with increasing time on HAART [OR 1.16 (0.93–1.46)]. After adjusting for time on HAART, fat loss is more likely with increasing stavudine use [OR 1.70 (1.34–2.15)]. There is no evidence of an association between reported fat changes and time on NNRTI therapy relative to PI therapy in those patients who used either one therapy or the other [OR 0.98 (0.56–1.63)].

Conclusion

Fat loss is more likely to be reported with increasing exposure to stavudine. We find no evidence of major differences between PI and NNRTI therapy in the risk of reported body fat changes.

Syncope in patients with pulmonary embolism: comparison between patients with syncope as the presenting symptom of pulmonary embolism and patients with pulmonary embolism without syncope

Syncope as an initial presentation of pulmonary embolism occurs in 10% of patients. We compared clinical and instrumental parameters in patients with syncope as the presenting symptom of pulmonary embolism and in patients with documented pulmonary embolism without syncope. Seventy patients with the diagnosis of pulmonary embolism and apparently stable clinical conditions were evaluated. They were divided in two groups: 10 patients with syncope as the presenting symptom of pulmonary embolism (group 1) and 60 patients without syncope (group 2). Patients with syncope showed a more pronounced tendency to present with main pulmonary artery embolus than patients without syncope (contingency coefficient = 0.301, p < 0.04; one-tailed). However, despite the evidence that patients with syncope have significant reductions in systolic and/or diastolic blood pressure, shock was not observed in any patient. In no case was thrombolytic treatment given and all patients received standard anticoagulation with unfractioned heparin and oral anticoagulant. We suggest that syncope in the setting of non-massive pulmonary embolism may be due to vaso-vagal mechanism that can lead to a reduction of arterial blood pressure when central artery thrombosis is involved.

Long-Term Virological Response to Multiple Sequential Regimens of Highly Active Antiretroviral Therapy for HIV Infection

Objective

Information about the virological response to sequential highly active antiretroviral therapy (HAART) for HIV infection is limited. The virological response to four consecutive therapies was evaluated in the Swiss HIV Cohort.

Design

Retrospective analysis in an observational cohort.

Methods

1140 individuals receiving uninterrupted HAART for 4.8 ±0.6 years were included. The virological response was classified as success (<400 copies/ml), low-level (LF: 400–5000 copies/ml) or high-level failure (HF: >5000 copies/ml). Potential determinants of the virological response, including patient demographics, treatment history and virological response to previous HAART regimens were analysed using survival and logistic regression analyses.

Results

40.1% failed virologically on the first (22.0% LF; 18.1% HF), 35.1% on the second (14.2% LF; 20.9% HF), 34.2% on the third (9.9% LF; 24.3% HF) and 32.7% on the fourth HAART regimen (9% LF; 23.7% HF). Nucleoside pre-treatment (OR: 2.34; 95% CI: 1.67–3.29) and low baseline CD4 T-cell count (OR: 0.79/100 cells rise; 95% CI: 0.72–0.88) increased the risk of HF on the first HAART. Virological failure on HAART with HIV-1 RNA levels exceeding 1000 copies/ml predicted a poor virological response to subsequent HAART regimens. A switch from a protease inhibitor- to a non-nucleoside reverse transcriptase inhibitor-containing regimen significantly reduced the risk of HF. Multiple switches of HAART did not affect the recovery of CD4 T lymphocytes.

Conclusion

Multiple sequential HAART regimens do not per se reduce the likelihood of long-term virological suppression and immunological recovery. However, early virological failure increases significantly the risk of subsequent unfavourable virological responses. The choice of a potent initial antiretroviral drug regimen is therefore critical. This study has been presented in part at the 10th Conference on Retroviruses & Opportunistic Infections. Boston, Mass., USA, 2003. Abstract #571.

Effect of Individual Cognitive Behaviour Intervention on Adherence to Antiretroviral Therapy: Prospective Randomized Trial

Objective

A high level of adherence to antiretroviral therapy is required for complete suppression of HIV replication, immunological and clinical effectiveness. We investigated whether cognitive behaviour therapy can improve medication adherence.

Design

Prospective randomized 1-year trial.

Setting

Collaboration of HIV university outpatient clinic and psychotherapists in private practice.

Participants

60 HIV-infected persons on stable anti-retroviral combination therapy and viral load below 50 copies/ml.

Intervention

Cognitive behaviour intervention in individual patients, in addition to standard of care.

Main outcome measures

Feasibility and acceptance of intervention; adherence to therapy assessed using medication event monitoring system (MEMS) and self-report questionnaire; virological failure; psychosocial measures.

Results

The median number of sessions for cognitive behaviour intervention per patient during the 1-year trial was 11 (range 2–25). At months 10–12, mean adherence to therapy as assessed using MEMS was 92.8% in the intervention and 88.9% in the control group ( P=0.2); the proportion of patients with adherence ≥95% was 70 and 50.0% ( P=0.014), respectively. While there was no significant deterioration of adherence during the study in the intervention arm, adherence decreased by 8.7% per year ( P=0.006) in the control arm. No differences between the intervention group and standard of care group were found regarding virological outcome. Compared with the control group, participants in the intervention group perceived a significant improvement of their mental health during the study period.

Conclusions

Cognitive behavioural support in addition to standard of care of HIV-infected persons is feasible in routine practice, and can improve medication adherence and mental health.

Impact of Genotypic Resistance Testing on Selection of Salvage Regimen in Clinical Practice

Objective

To determine whether genotypic resistance testing leads to selection of more potent drug regimens when compared to regimens based on treatment history only.

Design

Prospective, tertiary care centre-based study. Patients: One-hundred-and-forty-five HIV-infected adults on stable antiretroviral therapy (ART) for >6 months experiencing virological failure.

Methods

The physicians’ decision-making process when choosing a salvage regimen was prospectively documented: at time of virological failure, on ‘failing ART’, genotyping was performed and a hypothetical ‘clinical expert ART’ based upon patient's drug history was documented. Subsequently, data on resistance mutations, rating by a decision support software and drug history were used to define ‘genotyping ART’. After discussion with the patient, final treatment, ‘new personalized ART’ was chosen and prescribed. To compare the relative potency of the four ART regimens in a standardized manner, a resistance score ranging from 1 (best) to 8 (worst) based on drug ranking by decision support software was attributed to each ART regimen. Virological and immunological outcomes were analysed based on the magnitude of the resistance score.

Results

Median follow-up was 1.5 years. In all 145 patients, median resistance scores for the stepwise selected ART regimens were: ‘failing ART’: 4.5, ‘clinical expert ART’: 1.8, ‘genotyping ART’: 1.5 and ‘new personalized ART’: 2. The latter was 1.5 in patients who effectively switched to ‘new personalized ART’ ( n=89). Lower resistance scores translated into significantly improved virological response after initiation of ‘new personalized ART’. In multivariable analysis, lower resistance scores, lower baseline HIV RNA levels and use of novel antiretroviral drugs were associated with the probability of reducing plasma viraemia to <50 copies/ml. Conclusions: This study suggests that treatment choices including genotype and decision support software were virologically superior to those based on drug history only.

Time-resolved X-ray powder diffraction on a three-way catalyst at the GILDA beamline

Time-resolved X-ray diffraction experiments carried out at the beamline BM08-GILDA of ESRF allowed a study of the structural modifications taking place in a Pt/ceria-zirconia catalyst while the CO oxidation reaction was in progress. The capillary tube in which the sample is stored acts effectively as a chemical microreactor that ensures homogeneity of the sample treatments and minimization of diffusion effects. During the flowing of the reactant CO/He mixture, the investigated catalyst undergoes a fast Ce(IV)-Ce(III) partial reduction that involves the release of one O atom for every two reduced Ce cations. Because Ce(III) has a larger ionic radius than Ce(IV), the structural modification produces an increase of the lattice constant of the ceria-zirconia mixed oxide, and this increase is monitored by the translating imaging-plate device implemented at GILDA. The CO(2) resulting from the oxidation of the fluxed CO is monitored by a quadrupole mass spectrometer during the recording of the time-resolved X-ray diffraction pattern. The chemical and structural information was combined to show that the CO(2) yield is nearly constant until the catalytic system can provide oxygen for the reaction, while the structural rearrangement of the catalyst is delayed with respect to the switching on of the CO/He flux. After this induction time, during which CO(2) is produced with no structural modification of the catalyst, a fast increase of the lattice constant takes place.

Potential role of immune modulation in the effective long-term control of HIV-1 infection

Recent advances in HIV-1 pathogenesis, and in defining virological and immunological responses to highly active antiretroviral therapy (HAART), along with the identification of the numerous drawbacks of HAART, have clearly demonstrated that the eradication of the virus is not a feasible therapeutic goal, and that there is an urgent need to develop other approaches to fight HIV-1 infection. Novel therapeutic approaches of immune modulation have recently been evaluated in pilot clinical trials. First, treating primary HIV-1 infection with cyclosporin A (CsA) coupled with HAART to target massive immune activation extends the benefits achieved with HAART during primary HIV-1 infection and might contribute to the establishment of a more favourable immunological set-point affecting the ultimate pattern and rate of disease progression. Second, treating chronic HIV-1 infection in patients with long-term suppression of virus replication induced by HAART, with the addition of mycophenolate mofetil (MMF) reduces the pool of activated CD4+ T lymphocytes able to support productive HIV-1 infection, and might have an indirect impact on the pool of resting, latently infected CD4+ T cells, contributing to its depletion in vivo. The important question is clearly whether these results will have an impact on the clinical management of patients with HIV-1 infection, determining the precise therapeutic function of drugs like CsA and MMF, thus investigating the effects of these drugs on residual viral replication and the decay of the latent reservoir, on long-term immunological benefit, and, ultimately, on clinical benefit.

Effects of CCR5-Delta32, CCR2-64I, and SDF-1 3'A alleles on HIV-1 disease progression: An international meta-analysis of individual-patient data

BACKGROUND

Studies relating certain chemokine and chemokine receptor gene alleles with the outcome of HIV-1 infection have yielded inconsistent results.

OBJECTIVE

To examine postulated associations of genetic alleles with HIV-1 disease progression.

DESIGN

Meta-analysis of individual-patient data.

SETTING

19 prospective cohort studies and case-control studies from the United States, Europe, and Australia.

PATIENTS

Patients with HIV-1 infection who were of European or African descent.

MEASUREMENTS

Time to AIDS, death, and death after AIDS and HIV-1 RNA level at study entry or soon after seroconversion. Data were combined with fixed-effects and random-effects models.

RESULTS

Both the CCR5-Delta32 and CCR2-64I alleles were associated with a decreased risk for progression to AIDS (relative hazard among seroconverters, 0.74 and 0.76, respectively; P = 0.01 for both), a decreased risk for death (relative hazard among seroconverters, 0.64 and 0.74; P < 0.05 for both), and lower HIV-1 RNA levels after seroconversion (difference, -0.18 log(10) copies/mL and -0.14 log(10) copies/mL; P < 0.05 for both). Having the CCR5-Delta32 or CCR2-64I allele had no clear protective effect on the risk for death after development of AIDS. The results were consistent between seroconverters and seroprevalent patients. In contrast, SDF-1 3'A homozygotes showed no decreased risk for AIDS (relative hazard for seroconverters and seroprevalent patients, 0.99 and 1.03, respectively), death (relative hazard, 0.97 and 1.00), or death after development of AIDS (relative hazard, 0.81 and 0.97; P > 0.5 for all).

CONCLUSIONS

The CCR5-Delta32 and CCR2-64I alleles had a strong protective effect on progression of HIV-1 infection, but SDF-1 3'A homozygosity carried no such protection.

Methadone blood concentrations are decreased by the administration of abacavir plus amprenavir

Abacavir and amprenavir, a nucleoside reverse transcription inhibitor and a protease inhibitor, respectively, are new drugs used for the treatment of HIV. Methadone blood concentrations were measured in five addict patients receiving methadone maintenance therapy before and after introduction of abacavir plus amprenavir. The administration of these two drugs for a median period of 14 days resulted in a significant reduction (P = 0.043) of methadone concentration, with a median decrease to 35% of the original concentration (range 28-87%). Two patients reported on several occasions nausea in the morning before the intake of the daily methadone dose, which is compatible with withdrawal reaction to opioids. Because amprenavir is a cytochrome P4503A4 substrate and is involved in the metabolism of methadone, reduction of methadone concentrations could be explained by an induction of cytochrome P4503A4.

Induction of a cytotoxic T-cell response to HIV-1 proteins with short synthetic peptides and human compatible adjuvants

The goal of this study was the induction of a strong CTL response against multiple CTL epitopes present in HIV proteins using short synthetic peptides. Four HLA-A2.1 restricted peptides (RT 476-484, p17 77-85, gp41 814-823, RT 956-964) that showed stable binding to the HLA-A2.1 molecule in an in vitro binding assay were able to elicit a strong specific immune response in HLA-A2.1 transgenic mice when injected with IFA or Montanide. The use of biodegradable microspheres (MS) as adjuvant was also successfully tested for all peptides. When the peptides were injected as a mixture the response was weaker as compared to individual injections of the peptides indicating the occurrence of immunodominance (ID). We are currently investigating whether ID can be overcome by a combined injection of peptide loaded MS with different release patterns. Taken together, it seems feasible to induce a specific CTL response in HLA-A2.1 transgenic mice against several HIV proteins using short synthetic peptides and human compatible adjuvants.

The virological and immunological consequences of structured treatment interruptions in chronic HIV-1 infection

BACKGROUND

Some individuals with chronic HIV-1 infection have discontinued their drug therapy with consequent plasma virus rebound. In a small number of patients, a delayed or absent rebound in plasma virus load has been noted after drug cessation, apparently associated with prior drug interruptions and autologous boosting of HIV-1 specific immune responses. We hypothesized that cyclic structured treatment interruptions structured treatment interruptions (STI) could augment HIV-1 specific immune responses in chronic HIV-1 infection, which might help to control HIV-1 replication off therapy.

METHODS

We initiated an STI pilot study in 10 antiretroviral treatment-naive HIV-1 chronically infected subjects with baseline CD4 T-cell counts > 500 x 10(6) cells/l and plasma viral load > 5000 copies/ml who received highly active antiretroviral therapy (HAART) for 1 year with good response (plasma viral load < 20 copies/ml for at least 32 weeks). Three cycles of HAART interruption were performed.

RESULTS

In all of the patients viral load rebounded, but doubling times increased significantly between the first and third stops (P = 0.008), and by the third stop, six out of nine subjects had a virological set-point after a median 12 months off therapy that was lower than baseline before starting HAART (ranging from 0.6 log(10) to 1.3 log(10) lower than baseline) and in four it remained stable below 5000 copies/ml. Those subjects who controlled viral replication developed significantly stronger HIV-1 specific cellular immune responses than subjects lacking spontaneous decline (P < 0.05). During viral rebounds no genotypic or phenotypic changes conferring resistance to reverse trancriptase inhibitors or protease inhibitors was detected, but mean absolute CD4 T-cell counts declined significantly, although never below 450 x 10(6)/l and the mean value at 12 months off therapy was significantly higher than the pre-treatment level (P = 0.004).

CONCLUSIONS

Our findings suggest that STI in chronic HIV-1 infection might augment HIV-1-specific cellular immune responses associated with a spontaneous and sustained drop in plasma viral load in some subjects but at the potential cost of lower CD4 T-cell counts.