Comprehensive analysis of frequency and phenotype of T regulatory cells in HIV infection: CD39 expression of FoxP3+ T regulatory cells correlates with progressive disease.

There are conflicting data about the frequency and role of regulatory T cells (Tregs) during the course of HIV infection. Peripheral blood of a large cohort of HIV-infected patients (n = 131) at different stages of disease, including 15 long-term nonprogressors and 21 elite controllers, was analyzed to determine the frequency and phenotype of Tregs, defined as CD4(+), CD25(high), CD127(low), FoxP3(high) cells. A significantly increased relative frequency of Tregs within the CD4(+) compartment of HIV(+) patients compared to that of healthy controls (P < 0.0001) was observed. Additionally, the relative frequency of Tregs directly correlated with HIV viral load and inversely with CD4(+) counts. However, the absolute Treg number was reduced in HIV-infected patients versus healthy controls (P < 0.0001), with the exception of elite controllers (P > 0.05). The loss of absolute Treg numbers coincided with rising markers of immune activation (P < 0.0006). The initiation of antiviral therapy significantly increased absolute Treg numbers (P < 0.0031). We find that the expression of CD39, a newly defined ectonucleotidase with immunomodulatory functions on Tregs, correlated with progressive HIV disease, HIV viral load, and immune activation. Of note, when tested in peripheral blood mononuclear cells of healthy volunteers, the in vitro capacity to suppress T-cell proliferation was limited to CD4(+), CD25(high), CD39(+) T cells. Interestingly, Tregs of elite controllers exhibited not only the highest expression of CCR5, CTLA-4, and ICOS but also the lowest level of CD39. The data presented here reconcile the seemingly contradictory results of previous studies looking at Tregs in HIV and highlight the complexity of Treg-mediated immunoregulation during human viral infections.

Efficacy of short-term monotherapy with maraviroc, a new CCR5 antagonist, in patients infected with HIV-1.

We assessed the efficacy and safety of 10-d monotherapy with the orally administered CCR5 antagonist maraviroc in 63 HIV-1-positive individuals prescreened for the absence of CXCR4-using virus. Maximum reduction in viral load occurred at a median of 10-15 d, with a mean reduction of >or=1.6 log(10) copies/ml at all twice daily doses >or=100 mg. These results provide proof of concept that CCR5 antagonism is a viable antiretroviral therapeutic approach.

Timing of initiation of antiretroviral therapy in AIDS-free HIV-1-infected patients: a collaborative analysis of 18 HIV cohort studies.

BACKGROUND: The CD4 cell count at which combination antiretroviral therapy should be started is a central, unresolved issue in the care of HIV-1-infected patients. In the absence of randomised trials, we examined this question in prospective cohort studies. METHODS: We analysed data from 18 cohort studies of patients with HIV. Antiretroviral-naive patients from 15 of these studies were eligible for inclusion if they had started combination antiretroviral therapy (while AIDS-free, with a CD4 cell count less than 550 cells per microL, and with no history of injecting drug use) on or after Jan 1, 1998. We used data from patients followed up in seven of the cohorts in the era before the introduction of combination therapy (1989-95) to estimate distributions of lead times (from the first CD4 cell count measurement in an upper range to the upper threshold of a lower range) and unseen AIDS and death events (occurring before the upper threshold of a lower CD4 cell count range is reached) in the absence of treatment. These estimations were used to impute completed datasets in which lead times and unseen AIDS and death events were added to data for treated patients in deferred therapy groups. We compared the effect of deferred initiation of combination therapy with immediate initiation on rates of AIDS and death, and on death alone, in adjacent CD4 cell count ranges of width 100 cells per microL. FINDINGS: Data were obtained for 21 247 patients who were followed up during the era before the introduction of combination therapy and 24 444 patients who were followed up from the start of treatment. Deferring combination therapy until a CD4 cell count of 251-350 cells per microL was associated with higher rates of AIDS and death than starting therapy in the range 351-450 cells per microL (hazard ratio [HR] 1.28, 95% CI 1.04-1.57). The adverse effect of deferring treatment increased with decreasing CD4 cell count threshold. Deferred initiation of combination therapy was also associated with higher mortality rates, although effects on mortality were less marked than effects on AIDS and death (HR 1.13, 0.80-1.60, for deferred initiation of treatment at CD4 cell count 251-350 cells per microL compared with initiation at 351-450 cells per microL). INTERPRETATION: Our results suggest that 350 cells per microL should be the minimum threshold for initiation of antiretroviral therapy, and should help to guide physicians and patients in deciding when to start treatment.

Prevalence- and gender-specific immune response to opportunistic infections in HIV-infected patients in Lesotho.

BACKGROUND: The objective of this study was to assess the seroprevalence of coinfecting viruses and Treponema pallidum (T. pallidum) in a cohort of 205 antiretrovirally treated HIV-infected individuals (152 females and 53 males, aged: 19-71 years) in rural Lesotho. Furthermore agent-specific immune responses were investigated by analyzing antibody titers against herpes simplex virus type 2 (HSV-2) and against T. pallidum. METHODS: Serum samples were tested by enzyme-linked immunosorbent assay for antibodies against HSV-2, cytomegalovirus, hepatitis A, B, and C viruses, and T. pallidum. RESULTS: Seroprevalences (95% confidence intervals) were found to be 100% (98.5%-100%) for anti-cytomegalovirus, 98.5% (95.7%-99.7%) for anti-hepatitis A virus, 35.5% (28.9%-42.6%) for anti-HBc, 5.5% (2.8%-9.6%) for hepatitis B surface antigen, and 0.5% (0.0%-2.8%) for anti-hepatitis C virus. Only 78.5% (72.2%-84.0%) were anti-HSV-2 positive and 29.0% (22.8%-35.8%) had antibodies against T. pallidum. Only anti-HSV-2 titers showed gender- and CD4 cell-count dependent differences: females with >500 CD4 cells/microL had an average anti-HSV-2 titer of 446 compared with males of 398 AU/mL (not significant), but in those with 250 to 500 CD4 cells/microL, there was a significant difference with a mean titer of 467 compared to 302 AU/mL in males (P = 0.001). CONCLUSIONS: A high seroprevalence of CMV, HAV, and HBV was found in both genders. One-third of the patients had been exposed to HBV and T. pallidum. The generally high HSV-2 prevalence showed gender- and CD4 cell count-dependent differences in HSV-2 antibody titer.

Variable impact on mortality of AIDS-defining events diagnosed during combination antiretroviral therapy: not all AIDS-defining conditions are created equal.

BACKGROUND: The extent to which mortality differs following individual acquired immunodeficiency syndrome (AIDS)-defining events (ADEs) has not been assessed among patients initiating combination antiretroviral therapy. METHODS: We analyzed data from 31,620 patients with no prior ADEs who started combination antiretroviral therapy. Cox proportional hazards models were used to estimate mortality hazard ratios for each ADE that occurred in >50 patients, after stratification by cohort and adjustment for sex, HIV transmission group, number of antiretroviral drugs initiated, regimen, age, date of starting combination antiretroviral therapy, and CD4+ cell count and HIV RNA load at initiation of combination antiretroviral therapy. ADEs that occurred in <50 patients were grouped together to form a "rare ADEs" category. RESULTS: During a median follow-up period of 43 months (interquartile range, 19-70 months), 2880 ADEs were diagnosed in 2262 patients; 1146 patients died. The most common ADEs were esophageal candidiasis (in 360 patients), Pneumocystis jiroveci pneumonia (320 patients), and Kaposi sarcoma (308 patients). The greatest mortality hazard ratio was associated with non-Hodgkin's lymphoma (hazard ratio, 17.59; 95% confidence interval, 13.84-22.35) and progressive multifocal leukoencephalopathy (hazard ratio, 10.0; 95% confidence interval, 6.70-14.92). Three groups of ADEs were identified on the basis of the ranked hazard ratios with bootstrapped confidence intervals: severe (non-Hodgkin's lymphoma and progressive multifocal leukoencephalopathy [hazard ratio, 7.26; 95% confidence interval, 5.55-9.48]), moderate (cryptococcosis, cerebral toxoplasmosis, AIDS dementia complex, disseminated Mycobacterium avium complex, and rare ADEs [hazard ratio, 2.35; 95% confidence interval, 1.76-3.13]), and mild (all other ADEs [hazard ratio, 1.47; 95% confidence interval, 1.08-2.00]). CONCLUSIONS: In the combination antiretroviral therapy era, mortality rates subsequent to an ADE depend on the specific diagnosis. The proposed classification of ADEs may be useful in clinical end point trials, prognostic studies, and patient management.

Decrease of atazanavir and lopinavir plasma concentrations in a boosted double human immunodeficiency virus protease inhibitor salvage regimen.

The human immunodeficiency virus protease inhibitor combination of atazanavir (ATV)-lopinavir-ritonavir was reported to exhibit a mutual pharmacoenhancement of plasma lopinavir and ATV concentrations which may be beneficial for salvage patients. We identified 17 patients in our pharmacokinetic database taking this combination and found conflicting results. Plasma concentrations of both ATV and lopinavir were modestly, although not significantly, decreased when the drugs were coadministered. Therefore, patients should be selected carefully for this regimen and frequent clinical and therapeutic drug monitoring is strongly advised.

Determinants of virological failure after successful viral load suppression in first-line highly active antiretroviral therapy.

BACKGROUND: We aimed to investigate the long-term virological outcomes of a cohort initially showing good responses to first-line highly active antiretroviral therapy (HAART) with no evidence ofvirological failure during the first year after achieving viral load (VL) undetectability (<50 copies/ml). METHODS: Virological failure was defined as a confirmed VL >400 copies/ml or a single VL >400 copies/ml followed by a treatment change or end of follow-up. Risk factors for low-level VL rebound (50-400 copies/ml) in the first year after achieving undetectability and for virological failure during subsequent follow-up were investigated by logistic and Poisson regression. RESULTS: In the first year after achieving VL undetectability, 354/1386 (25.5%) patients experienced low-level VL rebound, the remaining patients maintained consistent undetectability. Low-level rebound occurred less commonly with non-nucleoside reverse transcriptase inhibitor (NNRTI)-based HAART than with other regimens (P = 0.01). Over median 2.2 (range 0.0-7.4) years of subsequent follow-up, 86 (6.2%) patients experienced virological failure, corresponding to 2.30 failures per 100 person-years (95% confidence interval [CI] 1.82-2.79). Independent predictors of virological failure included low-level rebound during the first year after achieving undetectability relative to consistent undetectability (rate ratio [RR] 2.18, 95%0 CI 1.15-4.10), female gender (RR 1.79, 95% CI 1.12-2.85) and receiving a ritonavir-boosted protease inhibitor (Pl/r) relative to NNRTI-based HAART (RR 1.88, 95% CI 1.02-3.46). CONCLUSIONS: Patients on first-line HAART who maintain consistent VL undetectability for 1 year have a low risk of subsequent virological failure. A subset might benefit from targeted interventions, including women and patients on Pl/r-based HAART.

Pharmacokinetics, safety and efficacy of saquinavir/ ritonavir 1,000/100 mg twice daily as HIV type-1 therapy and transmission prophylaxis in pregnancy.

BACKGROUND: A saquinavir/ritonavir-containing regimen is one option for the prevention of mother-to-child transmission of HIV during pregnancy. We evaluated the pharmacokinetics, efficacy and safety of saquinavir/ritonavir 1,000/100 mg twice daily plus nucleos(t)ide reverse transcriptase inhibitors in 13 women during late pregnancy and compared the results to those of 15 non-pregnant women. METHODS: Protease inhibitor plasma concentration profiles were assessed at 12 h using a standardized therapeutic drug monitoring procedure and measured by LC-MS/MS. Minimum and maximum concentrations (C(min) and C(max)), area under the plasma concentration-time curve (AUC(0-12 h)), and total clearance (CL(total)) were compared between the groups and correlated to demographic, physiological and clinical cofactors. Antiviral and immunological efficacy and safety were investigated. RESULTS: The geometric means (90% confidence interval [CI]) for saquinavir C(min), C(max) and AUC(0-2 h) of pregnant versus non-pregnant women were 572 (437-717) versus 765 (485-1,052, P = 0.064) ng/ml, 2,168 (1,594-2,807) versus 3,344 (2,429-4,350; P = 0.045) ng/ml and 15,512 (11,657-19,943) versus 24,027 (17,454-31,548, P = 0.029) ng x h/ml. The geometric means (90% CI) for ritonavir C(min), C(max) and AUC(0+12 h) were 190 (148-234) versus 310 (240-381, P = 0.011) ng/ml, 781 (580-999) versus 1,552 (1,127-2,007, P = 0.004) ng/ml and 5,576 (4,303-7,006) versus 10,528 (8,131-13,177, P = 0.003) ng x h/ml. Age, weight, saquinavir dose per weight and body mass index differed significantly; saquinavir C(min) and AUC(0-12 h) were correlated with ritonavir C(min) and saquinavir dose per weight. After a mean of 11 weeks treatment, 12 of 13 pregnant women had a viral load < 400 copies/ml, which was similar to the results of non-pregnant women. CONCLUSIONS: Although saquinavir plasma concentrations were significantly lower in pregnant women compared with non-pregnant women, all pregnant women displayed a saquinavir AUC(0-12 h) > 10,000 ng x h/ml, 92.3% had a viral load < 400 copies/ml at birth. Saquinavir was well tolerated by the mothers and all newborn children were HIV type-1 negative at 18 months of age.

The steady-state pharmacokinetics of atazanavir/ritonavir in HIV-1-infected adult outpatients is not affected by gender-related co-factors.

OBJECTIVES: Pharmacokinetic differences, contributing to drug-related side effects, between men and women have been reported for HIV protease inhibitors. As only limited and inconclusive data on ritonavir-boosted atazanavir are available, we evaluated the respective steady-state pharmacokinetics in 48 male and 26 female HIV-1-infected adults receiving atazanavir/ritonavir 300/100 mg once-daily as part of their antiretroviral therapy. METHODS: Pharmacokinetic profiles (24 h) of atazanavir/ritonavir were assessed and measured by HPLC/tandem mass spectrometry. Geometric mean (GM; ANOVA) of minimum and maximum plasma drug concentrations (C(min) and C(max)), area under the concentration-time curve (AUC) and total clearance (CL(total)) were compared between the sexes and correlated to demographic (age, gender and ethnicity), physiological (weight and body mass index) and clinical (CD4+ cell count, HIV-RNA, co-medication and hepatitis serology) co-factors. RESULTS: The GM of the atazanavir AUC, C(max) and C(min) of men versus women were 32 643 versus 36 232 ng.h/mL [GM ratio (GMR) = 1.11, P = 0.435], 2802 versus 3211 ng/mL (GMR = 1.15, P = 0.305) and 398 versus 470 ng/mL (GMR = 1.18, P = 0.406), respectively. Although weight (80.6 versus 63.9 kg, P = 0.001) and body weight-adjusted atazanavir dose (3.84 versus 4.60 mg/kg, P = 0.013) were different between the sexes, no significant correlation to atazanavir pharmacokinetics was observed. A linear regression analysis detected significant correlations of atazanavir C(min) with ritonavir AUC (P < 0.001) and the co-administration of methadone oral solution (P = 0.032), and inverse correlations with the time since the first HIV infection diagnosis (P = 0.003) and the number of previous antiretroviral treatments (P = 0.022). CONCLUSIONS: Atazanavir/ritonavir steady-state pharmacokinetics was comparable in men and women, despite gender-related significant differences in atazanavir dose/body weight. The administration of atazanavir/ritonavir is pharmacokinetically safe; 95% of all trough samples were above the recommended plasma concentration of 150 ng/mL.

Platelet-leucocyte adhesion markers before and after the initiation of antiretroviral therapy with HIV protease inhibitors.

INTRODUCTION: Thromboembolic complications under antiretroviral therapy (ART) have been described in the past. In particular, the influence of protease inhibitors (PIs) on platelet activation and coagulation is currently under discussion. METHODS: HIV-1-infected, PI-naive adults (n = 18) were investigated before and 4 weeks after the start of the ART, consisting either of boosted PI regimens (n = 13) plus reverse transcriptase inhibitors (RTIs) or a double PI regimen (n = 5) without RTI co-medication. Administered PIs were saquinavir (n = 15), lopinavir (n = 4), fosamprenavir (n = 2) and atazanavir (n = 2). Platelet CD62P, CD40L (%+ cells) and PAC-1 binding [mean fluorescence intensity (MFI)] as well as monocyte CD11b (MFI) and monocyte-associated CD41 (%+ cells and MFI) expression were assessed by flow cytometry with or without platelet stimulation. To investigate the influence of platelets on coagulation, the endogenous thrombin potential (ETP) [render fluorescence units (RFI)] was determined. RESULTS: CD62P, PAC-1 binding and CD11b expression remained unchanged. In contrast, the mean+/-SD MFI of CD40L (from 18.2+/-9.0 to 25.5+/-10.4, P = 0.038) and CD41 (from 446.1+/-213.8 to 605.0+/-183.8, P = 0.010) as markers for increased platelet-leucocyte interaction increased significantly. The collagen-induced ETP time-to-peak was altered significantly from 23.8+/-11.4 to 17.0+/-4.2 min (P = 0.028), although the ETP RFI peak showed no evidence for increased procoagulatory capacity (47.1+/-18.6 to 57.3+/-19.9, P = 0.085). CONCLUSIONS: Effects of the evaluated PI HIV therapy on platelet function assessed under field conditions seem to be minor, not affecting all investigated parameters. We found no evidence for increased platelet activation under PI-containing ART. However, CD41 as a marker for increased platelet-leucocyte interaction and CD40L, which can contribute to atherosclerosis, increased significantly.

Switching from a toxicity-causing antiretroviral to enfuvirtide in patients with HIV: the SWITCH TOX study.

PURPOSE: Treatment-related toxicities frequently limit antiretroviral therapy for patients with HIV-1 infection. This study evaluated the changes in treatment-limiting toxicities when the primary toxicity-causing agent was replaced with enfuvirtide. METHOD: Adult patients with HIV-1 infection (N = 91) with antiretroviral treatment-limiting toxicities were enrolled in this multicenter, open-label, single-arm, 24-week study. Enfuvirtide 90 mg bid was administered instead of a single toxicity-causing component of the previous antiretroviral regimen. Changes in severity of antiretroviral toxicity, safety, tolerability, and maintenance of efficacy of the enfuvirtide regimen were evaluated at baseline and at 4, 8, 12, and 24 weeks. RESULTS: Eighty-four percent of participants completed the study. Injection site reactions with enfuvirtide caused premature withdrawal in 5 participants (5%); a further 10 participants (11%) also withdrew early. Overall antiretroviral-related, treatment-limiting toxicities improved or resolved in 53% of participants switching to enfuvirtide, remained unchanged in 43%, and worsened in 3%. At Week 24, 66% of participants (60/91; intent-to-treat population) maintained or improved their viral load category and 73% of participants (66/91) maintained or improved their CD4 cell counts. CONCLUSION: Replacing a toxicity-causing antiretroviral with enfuvirtide may reduce toxicity without compromising the efficacy of different antiretroviral regimens.

[No obvious difference in Streptococcus pneumoniae antibiotic resistance profiles--isolates from HIV-positive and HIV-negative patients]. / Vergleichbare Antibiotikaresistenz von Pneumokokkenisolaten HIV-positiver und -negativer Patienten.

BACKGROUND AND PURPOSE: HIV patients are overexposed to hospital environment, immune suppression, and antibiotic prophylaxes. Therefore, with HIV positive patients an increased risk for resistant bacterial rods is to be expected. The purpose of this case-control study was to determine the susceptibility patterns of pneumococci from adult patients in relation to their HIV status and to compare both patient groups. PATIENTS AND METHODS: Between January 2001 and December 2005, samples from internal medicine patients of one university hospital laboratory were investigated on culture of Streptococcus pneumoniae and in case of a positive vial, a resistance test was done by agar diffusion method. All patients with culture-confirmed infection due to pneumococci underwent a standardized retrospective evaluation in regard to demographic and clinical characteristics including HIV status. RESULTS: A total amount of 135 Streptococcus pneumoniae cultures could be assigned to 64 HIV-positive (A) and 71 HIV-negative patients (B), with susceptibility results for 134 isolates. Full susceptibility was seen in 44 (69.8% [A]) versus 42 (59.2% [B]) samples, reduced susceptibility ("intermediate-susceptible") was found in eight (12.7% [A]) versus 17 (23.9% [B]). Eleven (17.5% [A]) and twelve (16.9% [B]), respectively, out of all pneumococci were tested resistant to at least one antibiotic. Among these, resistance to erythromycin was most relevant (11.1% [A] and 11.3% [B]). None of the tested rods was resistant to penicillin. All differences between groups for susceptibility testing were not found significant. HIV-negative patients were significantly older, needed more often hospitalization and intensive care, and cultures for pneumococci were more frequently positive in primary sterile materials, such as cerebrospinal fluid and blood. The difference concerning death within 28 days following positive sample was just not significant as well as in immune suppression status of patients. HIV patients experienced more frequently an infection relapse and were more frequently smokers. CONCLUSION: No obvious difference in pneumococci resistance patterns was observed between HIV-positive and HIV-negative adult patients. The absence of resistance to penicillin underscores the importance of beta-lactams in case of typical community-acquired pneumonia; therefore, this class of antibiotics should be included in treatment guidelines as first-line drugs also for HIV patients. HIV-negative controls of this study were more aged and suffered from a higher morbidity, however, the fact that they were not significantly less immune suppressed may be special character of a university hospital control patient group. HIV patients presented in an earlier stage of their pneumococcal disease, probably due to a direct access to tertiary hospital medical supply. A higher relapse rate underscores the importance of pneumococcal vaccination for HIV patients.

Chronic renal failure among HIV-1-infected patients.

BACKGROUND: The role of exposure to antiretrovirals in chronic renal failure (CRF) is not well understood. Glomerular filtration rates (GFR) are estimated using the Cockcroft-Gault (CG) or Modification of Diet in Renal Disease (MDRD) equations. METHODS: Baseline was arbitrarily defined as the first recorded GFR; patients with two consecutive GFR < or = 60 ml/min per 1.73 m(2) were defined as having CRF. Logistic regression was used to determine odds ratio (OR) of CRF at baseline. ART exposure (yes/no or cumulative exposure) prior to baseline was included in multivariate models (adjusted for region of Europe, age, prior AIDS, CD4 cell count nadir, viral load, hypertension and use of nephrotoxic anti-infective therapy). RESULTS: Using CG, the median GFR at baseline (n = 4474) was 94.4 (interquartile range, 80.5-109.3); 158 patients (3.5%) had CRF. Patients with CRF were older (median, 61.9 versus 43.1 years), had lower CD4 cell count nadirs (median, 80 versus 137 cells/microl), and were more likely to be diagnosed with AIDS (44.3 versus 30.4%), diabetes (16.5 versus 4.3%) or hypertension (53.8 versus 26.4%), all P < 0.001. In a multivariate model any use of indinavir [odds ratio (OR) 2.49; 95% confidence interval (CI), 1.62-3.83] or tenofovir (OR, 2.18; 95% CI, 1.25-3.81) was associated with increased odds of CRF, as was cumulative exposure to indinavir (OR, 1.15 per year of exposure; 95% CI, 1.06-1.25) or tenofovir (OR, 1.60; 95% CI, 1.20-2.15). Highly consistent results were seen using the MDRD formula. CONCLUSIONS: Among antiretrovirals, only exposure to indinavir or tenofovir was associated with increased odds of CRF. We used a confirmed low GFR to define CRF to increase the robustness of our analysis, although there are several potential biases associated with this cross-sectional analysis.

The ability of four genotypic interpretation systems to predict virological response to ritonavir-boosted protease inhibitors.

BACKGROUND: : Limited information exists on the prognostic value of genotypic interpretation systems (GISs) for ritonavir-boosted protease inhibitors (PI/rs). We compared PI/r resistance levels ascribed by four GIS and examined their abilities to predict HIV-RNA reductions after starting a PI/r-based regimen (baseline). METHODS: : Data on viraemic (HIV-RNA > 500 copies/ml) patients starting a PI/r with a baseline resistance test were combined from an observational cohort study (EuroSIDA) and three randomized trials (MaxCmin1; MaxCmin2 and COLATE). The GIS surveyed were ANRS, DMC, REGA and Stanford. Factors associated with HIV-RNA change were identified through censored regression analysis. RESULTS: : We included 744 patients, of whom 67% were PI experienced. At baseline 12-28% (depending on the GIS) patients had a virus with predicted resistance/intermediate resistance to the PI/r initiated. Concordance between GISs on ascribed PI/r resistance levels was moderate: kappa values ranged from 0.01 to 1.00, with the lowest kappas seen for amprenavir. The median (interquartile range) baseline HIV-RNA was 4.4 (3.5-5.1) log10 and was reduced by 2.2 (2.1-2.3) log10 12 (9-13) weeks after baseline. GIS consistently showed greater HIV-RNA reductions as the ascribed level of sensitivity to the PI/r increased. Conversely, the number of other active drugs in the rest of the regimen, according to each GIS did not predict HIV-RNA reductions consistently. CONCLUSION: : Despite large variations in how GIS classify HIV susceptibility to PI/r, all GIS predicted HIV-RNA reductions of a similar magnitude. The ascribed level of susceptibility to other drugs in the regimen did not predict HIV-RNA decline.

Quadruple nucleoside therapy with zidovudine, lamivudine, abacavir and tenofovir in the treatment of HIV.

Highly active antiretroviral therapy (HAART) has significantly reduced morbidity and mortality in HIV-infected patients. However, problems such as short-term or long-term toxicity and the development of drug resistance could necessitate a change in the therapy regimen. Whereas various HAART options with low pill burden and favourable long-term tolerability profiles are available for naive patients, treatment of experienced patients tends to be more complex and remains a challenge. Treatment with class sparing nucleoside-only regimens could be an option in this context, but the combination of zidovudine (AZT), lamivudine (3TC) and abacavir (ABC) has shown to be inferior in terms of virological efficacy compared with the standard regimen. More promising data were obtained when AZT, 3TC and ABC were intensified with tenofovir (TDF), resulting in a quadruple nucleoside therapy. This regimen has demonstrated comparable potency to a standard regimen with AZT, 3TC and efavirenz in treatmentnaive patients. Additionally, it has shown to be an efficient treatment option especially in moderately pretreated patients. This is accredited to the potency of the single components and the antagonistic selection pressure of AZT and TDF. The presence of L210W, or at least two of the mutations 41L, 67N, 70R, 215F/Y or 219Q/E, at or before baseline seems to be a predictor of non-response, whereas the presence of M184V does not impede virological response and might even be advantageous. This review summarizes current data on the combined use of AZT, 3TC, ABC and TDF in regard to virological and immunological outcome as well as genotypic predictors of response.

Predictive factors for response to a boosted dual HIV-protease inhibitor therapy with saquinavir and lopinavir in extensively pre-treated patients.

OBJECTIVE: To evaluate predictive factors for therapy outcome of a boosted double-protease inhibitor (PI) regimen in 58 extensively pre-treated patients with HIV. METHODS: Patients received lopinavir/ritonavir 400/100 mg and saquinavir 1,000 mg twice daily without reverse transcriptase inhibitors (RTI). The primary outcome parameter was HIV RNA < 400 copies/ml at week 48, secondary parameters were HIV-1 RNA and CD4+ T-cell count changes from baseline to week 48. Pharmacokinetics, genotypic resistance and clinical and individual parameters were correlated with the clinical outcome in regression analyses. Covariates for the analyses were minimum plasma concentration (C(min)), maximum plasma concentration, area under the concentration versus time curve, half-life and clearance of lopinavir and saquinavir, the genotypic inhibitory quotients (GIQ) of archived (GI6(arch)) and baseline PI resistance mutations, previously taken antiretrovirals, archived and baseline viral resistance mutations, baseline HIV-1 RNA and CD4+ T-cell count. RESULTS: The analyses detected correlations between the primary outcome parameter and several factors: baseline CD4+ T-cell count (P = 0.001); absence of mutations at V82T/A/F/I/S plus 154M/V/L (P = 0.002) or K20M/R (P = 0.010); and lopinavir C(min)GIQ(arch) (P = 0.046). This regression model had a predictability of 97.0% for response to therapy. Covariates for the decrease of HIV-1 RNA from baseline to week 48 were baseline HIV-1 RNA (P < 0.001), lopinavir C(min)GIQ(arch) (P = 0.013), presence/absence of mutations at V82T/A/F/I/S or 184A/V plus L10I/R/V/F, 154M/V/L or L63P (P = 0.018), and previously taken antiretrovirals (P = 0.034). CONCLUSIONS: Baseline HIV-1 RNA < 5.0 log10 and CD4+ T-cell count > 200 cells/microl, lopinavir C(min)GIQ(arch) > 2,000 ng/ml and the absence of viral resistance mutations at V82T/A/F/I/S and 154M/V/L are highly predictive for therapeutic success of a regimen of saquinavir/lopinavir/ ritonavir without RTI in a heterogenic cohort of patients with an extensive pre-treatment history and highly variable pharmacokinetics.

Evolution of resistance mutations during low-level viral replication in HIV-1-infected patients treated with zidovudine/lamivudine/abacavir as a first-line regimen.

OBJECTIVE: Long-term evaluation of viral evolution in patients who continued first-line therapy with zidovudine/lamivudine/abacavir (Trizivir [TZV]) in the presence of low-level viral replication and assessment of the impact of mutational patterns selected under TZV on viral load (VL), CD4+ T-cell count (CD4) and subsequent therapeutic options. DESIGN: Analysis of viral evolution based on genotypic resistance tests (GRT) from samples collected during non-suppressive first-line therapy with TZV. METHODS: Patients from the Frankfurt HIV cohort with at least 3 months uninterrupted first-line therapy with TZV in whom VL and CD4 measurements were performed at baseline and at follow up were identified. Criteria for virological failure (VF) were two consecutive VL >400 copies/ml. GRTs were required at baseline, VF and last visit (LV). RESULTS: Initially, 23/119 patients were classified as VF; 4/23 were lost to follow up. Median time to VF was 48 weeks. Because of the observed virological and immunological benefit, patients continued TZV for a median of 87 weeks despite detectable viraemia. Median CD4 increase and VL reduction at LV were 120 cells/mm3 and 317,100 copies/ml, respectively, compared to baseline. After 54 weeks of treatment with detectable VL, three mutational patterns were observed: Group A (n=4) characterized by M184V without further regimen-associated mutations, group B (n=9) by M184V accompanied by one to three thymidine analogue mutations (TAMs), and group C (n=6) by M184V and four to six TAMs. No virological or CD4 parameters correlated with these patterns. Group A remained unchanged, thus preserving activity of most nucleoside analogues (NA). However, in the majority of patients (groups B and C) accumulation of mutations at different rates was observed, leading to a sequential loss of NA options. CONCLUSIONS: Continuous treatment with TZV in the presence of viral replication is associated with a stepwise accumulation of resistance mutations. M184V was present in all cases, not followed by further selection of TAMs in a small, unpredictable subgroup of patients. However, in the majority of patients selection of M184V was associated with accumulation of TAMs at different rates leading to a substantial loss of active NAs, despite continuous virological and immunological benefit when compared with baseline.

Risk of discontinuation of nevirapine due to toxicities in antiretroviral-naive and -experienced HIV-infected patients with high and low CD4+ T-cell counts.

INTRODUCTION: It is unknown whether the increased risk of toxicities in antiretroviral-naive HIV-infected patients initiating nevirapine-based (NVPc) combination antiretroviral therapy (cART) with high CD4+ T-cell counts is also observed when NVPc is initiated in cARTexperienced patients. PATIENTS AND METHODS: 1,571 EuroSIDA patients started NVPc after 1/1/1999, with CD4+ T-cell counts and viral load measured in the 6 months before starting treatment, and were stratified into four groups based on CD4+ T-cell counts at initiation of NVPc (high [H], > 400/mm3 or > 250/mm3 for male or female, respectively, or low [L], < or = 400/mm3 or 5250/mm3 for male or female) and prior antiretroviral experience (antiretroviral-naive [N] or -experienced [E]). Cox proportional hazards models compared the risks of discontinuation of nevirapine due to toxicities or patient/physician choice (TOXPC). RESULTS: After adjustment, there was a significantly lower risk of discontinuation of nevirapine due to TOXPC in the HE group (n = 588; proportion discontinued by 3/12 months: 10/17%, respectively) than in HN (n = 62; 21/32% respectively; overall relative hazard [RH]: 0.56; 95% confidence interval [CI]: 0.34-0.94; P = 0.027). This difference was most pronounced during the first 3 months of NVPc (RH: 0.44; 95% CI: 0.23-0.87; P = 0.017). There were no deaths in the 6 months after starting NVPc resulting from exposure to < 3 months of NVPc exposure within the HE group (incidence: 0; per 1,000 person-years follow up; 95% CI: 0-6.9). After adjustment, there were no differences between the HE and HN groups in discontinuation due to TOXPC in patients starting efavirenz-based cART (RH: 0.91; 95% CI: 0.60-1.38; P = 0.66) or protease-inhibitor-based cART (RH: 1.13; 95% CI: 0.77-1.66; P = 0.52). CONCLUSIONS: Results from this non-randomized study suggest that NVPc might be safer to initiate in antiretroviral-experienced than in antiretroviral-naive patients with high CD4+ T-cell counts.

The KLEAN study of fosamprenavir-ritonavir versus lopinavir-ritonavir, each in combination with abacavir-lamivudine, for initial treatment of HIV infection over 48 weeks: a randomised non-inferiority trial.

BACKGROUND: Lopinavir-ritonavir is a preferred protease inhibitor co-formulation for initial HIV-1 treatment. Fosamprenavir-ritonavir has shown similar efficacy and safety to lopinavir-ritonavir when each is combined with two nucleoside reverse transcriptase inhibitors. We compared the two treatments directly in antiretroviral-naive patients. METHODS: This open-label, non-inferiority study included 878 antiretroviral-naive, HIV-1-infected patients randomised to receive either fosamprenavir-ritonavir 700 mg/100 mg twice daily or lopinavir-ritonavir 400 mg/100 mg twice daily, each with the co-formulation of abacavir-lamivudine 600 mg/300 mg once daily. Primary endpoints were proportion of patients achieving HIV-1 RNA less than 400 copies per mL at week 48 and treatment discontinuations because of an adverse event. The intent-to-treat analysis included all patients exposed to at least one dose of randomised study medication. This study is registered with ClinicalTrials.gov, number NCT00085943. FINDINGS: At week 48, non-inferiority of fosamprenavir-ritonavir to lopinavir-ritonavir (95% CI around the treatment difference -4.84 to 7.05) was shown, with 315 of 434 (73%) patients in the fosamprenavir-ritonavir group and 317 of 444 (71%) in the lopinavir-ritonavir group achieving HIV-1 RNA less than 400 copies per mL. Treatment discontinuations due to an adverse event were few and occurred with similar frequency in the two treatment groups (fosamprenavir-ritonavir 53, 12%; lopinavir-ritonavir 43, 10%). Diarrhoea, nausea, and abacavir hypersensitivity were the most frequent drug-related grade 2-4 adverse events. Treatment-emergent drug resistance was rare; no patient had virus that developed reduced susceptibility to fosamprenavir-ritonavir or lopinavir-ritonavir. INTERPRETATION: Fosamprenavir-ritonavir twice daily in treatment-naive patients provides similar antiviral efficacy, safety, tolerability, and emergence of resistance as lopinavir-ritonavir, each in combination with abacavir-lamivudine.

HIV treatment response and prognosis in Europe and North America in the first decade of highly active antiretroviral therapy: a collaborative analysis.

BACKGROUND: Highly active antiretroviral therapy (HAART) for the treatment of HIV infection was introduced a decade ago. We aimed to examine trends in the characteristics of patients starting HAART in Europe and North America, and their treatment response and short-term prognosis. METHODS: We analysed data from 22,217 treatment-naive HIV-1-infected adults who had started HAART and were followed up in one of 12 cohort studies. The probability of reaching 500 or less HIV-1 RNA copies per mL by 6 months, and the change in CD4 cell counts, were analysed for patients starting HAART in 1995-96, 1997, 1998, 1999, 2000, 2001, and 2002-03. The primary endpoints were the hazard ratios for AIDS and for death from all causes in the first year of HAART, which were estimated using Cox regression. RESULTS: The proportion of heterosexually infected patients increased from 20% in 1995-96 to 47% in 2002-03, and the proportion of women from 16% to 32%. The median CD4 cell count when starting HAART increased from 170 cells per muL in 1995-96 to 269 cells per muL in 1998 but then decreased to around 200 cells per muL. In 1995-96, 58% achieved HIV-1 RNA of 500 copies per mL or less by 6 months compared with 83% in 2002-03. Compared with 1998, adjusted hazard ratios for AIDS were 1.07 (95% CI 0.84-1.36) in 1995-96 and 1.35 (1.06-1.71) in 2002-03. Corresponding figures for death were 0.87 (0.56-1.36) and 0.96 (0.61-1.51). INTERPRETATION: Virological response after starting HAART improved over calendar years, but such improvement has not translated into a decrease in mortality.