Evolution of drug resistance in HIV-infected patients remaining on a virologically failing combination antiretroviral therapy regimen

OBJECTIVE

To estimate the extent of drug resistance accumulation in patients kept on a virologically failing regimen and its determinants in the clinical setting.

DESIGN

The study focused on 110 patients of EuroSIDA on an unchanged regimen who had two genotypic tests performed at two time points (t0 and t1) when viral load was > 400 copies/ml.

METHODS

Accumulation of resistance between t0 and t1 was measured using genotypic susceptibility scores (GSS) obtained by counting the total number of active drugs (according to the Rega system v6.4.1) among all licensed antiretrovirals as of 1 January 2006. Patients were grouped according to the number of active drugs in the failing regimen at t0 (GSS_f-t0).

RESULTS

At t0, patients had been on the failing combination antiretroviral therapy (cART) for a median of 11 months (range, 6-50 months). Even patients with extensive resistance to the failing regimen were still receiving benefit from treatment. An overall 6-monthly increase of 1.96 (SD, 2.23) International Aids Society-mutations and an average loss of 1.25 (SD, 1.81) active drugs were estimated. In comparison with patients with GSS_f-t0 = 0, the number of active drugs lost was -1.08 [95% confidence interval (CI), -2.13 to -0.03; P = 0.04] in those with GSS_f-t0 of 0.5-1.5 and -1.24 (95% CI, -2.44 to -0.04; P = 0.04) in those with GSS_f-t0 >or= 2.

CONCLUSIONS

In patients kept on the same virologically failing cART regimen for a median of 6 months, there was considerable accumulation of drug resistance mutations, particularly in patients with initial low level of resistance to the failing regimen. Randomized comparisons of maintenance treatment strategies while awaiting a new suppressive therapy to become available are warranted.

Interruption of combination antiretroviral therapy and risk of clinical disease progression to AIDS or death

OBJECTIVES

The aim of the study was to compare incidence rates (IRs) of AIDS/death in patients with and without treatment interruption (TI) of combination antiretroviral therapy (cART) for periods of 3 months or more for different categories of CD4 cell count and viral load, and to determine risk factors for clinical progression to AIDS/death.

METHODS

Patients starting cART with a CD4 cell count and a viral load available within 6 months of starting cART were included in the study. The IR and risk factors of TI were determined. We assessed the incidence rate ratios (IRRs) for TI and AIDS/death events using Poisson regression models.

RESULTS

Of 3811 patients included in the study, 26% were ART-naïve prior to cART. The median date of starting cART was July 1997, the median CD4 cell count was 226 cells/microL and the median viral load was 4.36 log(10) HIV-1 RNA copies/mL. We observed 1243 interruptions and 403 AIDS-events/deaths. The IR of AIDS/death was higher in patients with lower CD4 cell counts or higher viral loads, regardless of TI. After adjusting for baseline factors, the IR of AIDS/death was significantly higher in the TI group than in the non-TI group [IRR 2.63; 95% confidence interval (CI) 2.01-3.44; P<0.0001]; this could be explained by current CD4 cell counts and viral loads, as the CD4 cell count- and viral load-adjusted IRR was 1.14 (95% CI 0.86-1.51; P=0.37). Within the TI group, patients with a current CD4 cell count of <200 cells/microL had a 3-fold higher risk of AIDS/death than those with a CD4 cell count of 200-350 cells/microL, whereas patients with a current CD4 cell count of >350 cells/microL had a 4-fold lower risk of disease progression.

CONCLUSIONS

TI is common in clinical practice. The risk of AIDS/death increased more than 2-fold for patients stopping all cART regimen drugs for 3 months or more. Among patients experiencing a TI, those with low CD4 cell counts, high viral loads or prior AIDS had an increased risk of AIDS/death. Hence, TI should be discouraged and closely monitored if it occurs.

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.

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.

Evaluation of anti-pneumococcal capsular antibodies as adjunctive therapy in experimental pneumococcal meningitis

OBJECTIVE

Bacteraemia concomitant with meningitis has been shown to greatly affect outcome. Consequently, the efficacy of serotype-specific anti-pneumococcal antiserum (APAS) was investigated in a rat model of pneumococcal meningitis.

METHODS

Rats were infected with Streptococcus pneumoniae serotype 3. All rats received ceftriaxone starting 26 h post-infection. APAS was administered either at the time of infection or 26 h post-infection and effects were compared with rats treated with antibiotics only.

RESULTS AND CONCLUSION

A significant clinical benefit was found when APAS was given at the time of infection whereas no effect was found when administered 26 h after infection. This work indicates that the clinical value of using APAS in pneumococcal meningitis may be limited.

Factors associated with the development of opportunistic infections in HIV-1-infected adults with high CD4+ cell counts: a EuroSIDA study

BACKGROUND

Limited data exist on factors predicting the development of opportunistic infections (OIs) at higher-than-expected CD4(+) cell counts in human immunodeficiency virus (HIV) type 1-infected adults.

METHODS

Multivariate Poisson regression models were used to determine factors related to the development of groups of OIs above their respective traditional upper CD4(+) cell count thresholds: group 1 (>or=100 cells/ microL), OIs caused by cytomegalovirus, Mycobacterium avium complex, and Toxoplasma gondii; group 2 (>or=200 cells/ microL), Pneumocystis pneumonia and esophageal candidiasis; and group 3 (>or=300 cells/ microL), pulmonary and extrapulmonary tuberculosis.

RESULTS

In groups 1, 2, and 3, 71 of 9,219, 125 of 7,934, and 36 of 7,838 patients, respectively, developed >or=1 intragroup OI. The strongest predictor of an OI in groups 1 and 2 was current CD4(+) cell count (for group 1, incidence rate ratio [IRR] per 50% lower CD4(+) cell count, 5.37 [95% confidence interval {CI}, 3.71-7.77]; for group 2, 4.28 [95% CI, 2.98-6.14]). Injection drug use but not current CD4(+) cell count predicted risk in group 3. Use of antiretroviral treatment was associated with a lower incidence of OIs in all groups, likely by reducing HIV-1 RNA levels (IRR per 1-log(10) copies/mL higher HIV-1 RNA levels for group 1, 1.50 [95% CI, 1.15-1.95]; for group 2, 1.68 [95% CI, 1.40-2.02]; and for group 3, 1.89 [95% CI, 1.40-2.54]).

CONCLUSION

Although the absolute incidence is low, the current CD4(+) cell count and HIV-1 RNA level are strong predictors of most OIs in patients with high CD4(+) cell counts.

Liver-related deaths in persons infected with the human immunodeficiency virus: the D:A:D study

BACKGROUND

An increasing proportion of deaths among human immunodeficiency virus (HIV)-infected persons with access to combination antiretroviral therapy (cART) are due to complications of liver diseases.

METHODS

We investigated the frequency of and risk factors associated with liver-related deaths in the Data Collection on Adverse Events of Anti-HIV Drugs study, which prospectively evaluated 76 893 person-years of follow-up in 23 441 HIV-infected persons. Multivariable Poisson regression analyses identified factors associated with liver-related, AIDS-related, and other causes of death.

RESULTS

There were 1246 deaths (5.3%; 1.6 per 100 person-years); 14.5% were from liver-related causes. Of these, 16.9% had active hepatitis B virus (HBV), 66.1% had hepatitis C virus (HCV), and 7.1% had dual viral hepatitis co-infections. Predictors of liver-related deaths were latest CD4 cell count (adjusted relative rate [RR], 16.1; 95% confidence interval [CI], 8.1-31.7 for <50 vs > or =500/microL), age (RR, 1.3; 95% CI, 1.2-1.4 per 5 years older), intravenous drug use (RR, 2.0; 95% CI, 1.2-3.4), HCV infection (RR, 6.7; 95% CI, 4.0-11.2), and active HBV infection (RR, 3.7; 95% CI, 2.4-5.9). Univariable analyses showed no relationship between cumulative years patients were receiving cART and liver-related death (RR, 1.00; 95% CI, 0.93-1.07). Adjustment for the most recent CD4 cell count and patient characteristics resulted in an increased risk of liver-related mortality per year of mono or dual antiretroviral therapy before cART (RR, 1.09; 95% CI, 1.02-1.16; P = .008) and per year of cART (RR, 1.11; 95% CI, 1.02-1.21; P = .02).

CONCLUSIONS

Liver-related death was the most frequent cause of non-AIDS-related death. We found a strong association between immunodeficiency and risk of liver-related death. Longer follow-up is required to investigate whether clinically significant treatment-associated liver-related mortality will develop.

Hearing loss and cochlear damage in experimental pneumococcal meningitis, with special reference to the role of neutrophil granulocytes

Hearing loss is a well-known sequelae from meningitis, affecting up to 25% of survivors. However, the principal components of the infectious and inflammatory reaction responsible for the sensorineural hearing loss remain to be identified. The present study aimed to investigate the impact of an augmented neutrophil response on the development of hearing loss and cochlear damage in a model of experimental pneumococcal meningitis in rats. Hearing loss and cochlear damage were assessed by distortion product oto-acoustic emissions (DPOAE), auditory brainstem response (ABR) and histopathology in rats treated with ceftriaxone 28 h after infection. Rats were treated with Granulocyte Colony Stimulating Factor (G-CSF) initiated prior to infection, 28 h after infection or with ceftriaxone only. Rats were followed for 7 days, and assessment of hearing was performed before infection and 24 h and day 8 after infection. Pretreatment with G-CSF increased hearing loss 24 h after infection and on day 8 compared to untreated rats (Mann-Whitney, P = 0.012 and P = 0.013 respectively). The increased sensorineural hearing loss at day 8 was associated with significantly decreased spiral ganglion cell counts (P = 0.0006), increased damage to the organ of Corti (P = 0.007), increased areas of inflammatory infiltrates (P = 0.02) and increased white blood cell (WBC) counts in cerebrospinal fluid on day 8 after infection (P = 0.0084). Initiation of G-CSF 28 h after infection did not significantly affect hearing loss or cochlear pathology compared to controls. In conclusion, the inflammatory host reaction contributes significantly to the development of hearing loss in experimental meningitis.

HIV-1 Subtypes and Response to Combination Antiretroviral Therapy in Europe

Background

Combination antiretroviral therapy (cART) may vary in ability to suppress viral load and increase CD4+ T-cell count in people infected with different HIV-1 subtypes, possibly due to differences in resistance development. Antiretroviral drugs have predominantly been developed in Western Europe/North America on the basis of the most prevalent subtype, B. However, non-B subtypes are increasingly spreading worldwide.

Objective

To compare virological and immunological response to cART between patients infected with B and non-B subtypes across Europe.

Design

EuroSIDA prospective, observational cohort with 11,928 HIV-1-infected patients.

Methods

Response to cART was analysed in patients with subtypes determined pre-cART, via multivariable logistic regression on the first measurements 6–12 months after starting cART. A virological response was defined as a viral load <500 copies/ml and immunological response as a CD4+ T-cell count increase of ≥100 cells/mm3.

Results

Forty-five percent of patients were antiretroviral naive at initiation of cART. Virological suppression was achieved by 58% of 689 subtype-B-infected patients and 66% of 102 non-B-infected patients ( P=0.159). After adjustment for potential confounders, there was no significant difference in odds of achieving virological suppression (non-B compared with B; odds ratio [OR]: 1.05, 95% confidence interval [CI]: 0.58–1.93, P=0.866). An immunological response was achieved by 43% of 753 B-infected patients and 48% of 114 non-B-infected patients ( P=0.334). After adjustment, there was no significant difference in odds of an immunological response (OR: 1.17, 95% CI: 0.73–1.87, P=0.524).

Conclusions

There was no evidence of significant differences in virological or immunological response to cART between patients infected with HIV-1 B and non-B subtypes.

A Randomized Trial to Evaluate Continuation versus Discontinuation of Lamivudine in Individuals Failing A Lamivudine-Containing Regimen: The Colate Trial

Background

Lamivudine (3TC) therapy can cause the emergence of M184I/V. Previous studies suggest a higher fidelity of the mutant reverse transcriptase and lower replication capacity of the mutant virus. No data exist from clinical comparative studies evaluating the benefit of M184I/V in patients receiving combination antiretroviral therapy (cART).

Methods

HIV-1-infected adults failing a 3TC-containing regimen were randomized to continue (On-3TC) or discontinue 3TC (Off-3TC) whilst receiving cART. The primary efficacy measure was the log10 average-area-under-the-curve-minus-baseline reduction in HIV RNA over 48 weeks. Cryopreserved plasma samples from patients with baseline and ≥1 follow-up sample with HIV RNA >500 copies/ml were sequenced for a nucleotide distances substudy. Evolutionary distances were compared between treatment arms and between viruses with and without M184I/V

Results

The overall 48-week log10 HIV RNA change was -1.4 (95% CI: -1.6, -1.1) for On-3TC ( n=65) and -1.5 (95% CI: -1.7, -1.2) for Off-3TC ( n=66; P=0.51). No difference was seen in the magnitude of the CD4+ T-cell count increases (median increase: 87 vs 76 cells/ml for 3TC vs Off-3TC, respectively). Thirty-seven patients had baseline and follow-up sequencing. Overall, there were 1.2 (95% CI: -2.2, 4.6) more nucleotide substitutions from baseline for Off-3TC patients ( P=0.50), and 10.7 (95% CI: 7.5, 14.0) fewer nucleotide changes in viruses containing M184I/V ( P<0.0001).

Conclusion

This study found no added virological or immunological benefit of continuing 3TC in patients on cART harbouring M184I/V Evolutionary distances from baseline were larger in viruses that did not contain M184I/V. More discernable benefits may be seen in patients with fewer drug options as potent cART may eclipse a benefit of M184I/V in COLATE.

Impact of Lamivudine on the Risk of Liver-Related Death in 2,041 Hbsag- and HIV-Positive Individuals: Results from An Inter-Cohort Analysis

Background

The impact of lamivudine (3TC) as part of combination antiretroviral therapy (cART) on the risk of liver-related death (LRD) in HIV/hepatitis B virus (HBV)-coinfected patients has not been extensively studied.

Methods

We performed an analysis involving HIV/HBV-coinfected patients in 13 cohorts who initiated cART. The end–point was LRD – that is, death with concomitant decompensated liver disease (DLD) or hepatocellular carcinoma – as the main cause. Incidence rates of LRD after initiation of cART were expressed as number of events per 100 person–years of follow–up (PYFU). A Poisson regression model adjusted for cohort, gender, mode of HIV transmission, CD4+ T-cell count at cART initiation, liver disease pre–cART, duration of 3TC before cART, and hepatitis C virus was used to assess the association between use of 3TC and risk of LRD.

Results

We analysed 2,041 patients. Follow–up after starting cART was 7,648 PYFU (5,569 spent on 3TC-containing regimens) with a median per person of 48 months (range: 2–91). Of the total, 217 subjects died; 57 deaths were liver-related resulting in a rate of 7.5 per 1,000 PYFU [95% confidence intervals (CI): 5.6–9.7]. The relative risk of LRD per extra year of 3TC use was 0.73 (95% CI: 0.59–0.90, P=0.004).

Conclusion

The use of 3TC was associated with a reduced risk of LRD over 4 years of follow–up. This study supports the current view that the use of 3TC as part of cART should be considered in patients who are tested positive for HBsAg.

Regional Changes Over Time in Initial Virologic Response Rates to Combination Antiretroviral Therapy Across Europe

BACKGROUND

Changes in virologic response to initial combination antiretroviral therapy (cART) over calendar time may indicate improvements in cART or emergence of primary resistance. Regional variations may identify differences in available antiretroviral drugs or patient management.

METHODS

Virologic response (viral load < 500 copies/mL) 6 to 12 months after starting cART was analyzed in antiretroviral-naive EuroSIDA patients. Analyses were stratified by region (south, central west, north, east) or time started cART (early, 1996-1997; mid, 1998-1999; late, 2000-1904).

RESULTS

Virologic suppression was achieved by 60% of 2102 patients: 57% south (n = 560), 61% central west (n = 466), 63% north (n = 606), 58% east (n = 470) (P = 0.091). An increase was observed over time: 52% early cART, 56% mid cART, 69% late cART (P < 0.001). Overall, there were significant effects of region (P = 0.026) and time (P < 0.001) on virologic response after adjustment for confounders. Stratified by period, regional differences were less evident (early cART, P = 0.967; mid cART, P = 0.291; late cART, P = 0.163). Stratified by region, temporal changes were observed (south, P = 0.061; central west, P < 0.001; north: P = 0.070; east, P = 0.001).

CONCLUSIONS

There was some evidence of regional differences in initial virologic response to cART. Improvements over time were observed, suggesting that so far, the effect of primary resistance has not been of sufficient magnitude to prevent increasing suppression rates.

Relationship between antiretrovirals used as part of a cART regimen and CD4 cell count increases in patients with suppressed viremia

BACKGROUND

It is unknown if the CD4 cell count response differs according to antiretroviral drugs used in combination antiretroviral therapy (cART) in patients with maximal virological suppression [viral load (VL) < 50 copies/ml].

OBJECTIVES

To compare the change in CD4 cell count over consecutive measurements with VL < 50 copies/ml at both time-points according to nucleoside backbones and other antiretrovirals used.

METHODS

Generalized linear models, accounting for multiple measurements within patients, were used to compare CD4 cell count changes after adjustment for antiretrovirals, time from starting cART, age, CD4 at first VL < 50 copies/ml, prior antiretroviral treatment, and change in CD4 cell count since starting cART.

RESULTS

We studied 28418 instances of VL < 50 copies/ml in 4041 patients. The mean annual change in CD4 cell count was +45.5/microl [95% confidence interval (CI) +39.4 to +51.6/microl). Comparing two drug nucleoside backbones, there was a lower annual change in CD4 cell count for zidovudine/lamivudine (n = 13038; -15.4/microl; P = 0.012) and for those on tenofovir (n = 1809; -27.3/microl; P = 0.029) compared to lamivudine/stavudine (n = 7339). Compared to the boosted-protease inhibitor regimen (n = 5915), use of an abacavir-based triple-nucleoside regimen was associated with a lower annual change in CD4 cell count (n = 2504 pairs; -26.1/microl; P = 0.011).

CONCLUSIONS

A nucleoside backbone of zidovudine/lamivudine or any tenofovir-based backbone was associated with significantly poorer increases in CD4 cell count compared to a nucleoside backbone of stavudine/lamivudine, as was an abacavir-based triple nucleoside regimen compared to a boosted protease inhibitor regimen. Long-term studies are needed to determine whether the differences in immunological response seen here translate into differences in the risk of clinical disease.

The use of the Framingham equation to predict myocardial infarctions in HIV-infected patients: comparison with observed events in the D:A:D Study

BACKGROUND

The D:A:D (Data Collection on Adverse Events of Anti-HIV Drugs) Study, a prospective observational study on a cohort of 23 468 patients with HIV infection, indicated that the incidence of myocardial infarction (MI) increased by 26% per year of exposure to combination antiretroviral treatment (CART). However, it remains unclear whether the observed increase in the rate of MI in this population can be attributed to changes in conventional cardiovascular risk factors.

OBJECTIVE

To compare the number of MIs observed among participants in the D:A:D Study with the number predicted by assuming that conventional cardiovascular risk equations apply to patients with HIV infection.

METHODS

The Framingham equation, a conventional cardiovascular risk algorithm, was applied to individual patient data in the D:A:D Study to predict rates of MI by duration of CART. A series of sensitivity analyses were performed to assess the effect of model and data assumptions. Predictions were extrapolated to provide 10-year risk estimates, and various scenarios were modelled to assess the expected effect of different interventions.

RESULTS

In patients receiving CART, the observed numbers of MIs during D:A:D follow up were similar to or somewhat higher than predicted numbers: 9 observed vs 5.5 events predicted, 14 vs 9.8, 22 vs 14.9, 31 vs 23.2 and 47 vs 37.0 for<1 year, 1-2 years, 2-3 years, 3-4 years and >4 years CART exposure, respectively. In patients who had not received CART, the observed number of MIs was fewer than predicted (3 observed vs 7.6 predicted). Nine per cent of the study population have a predicted 10-year risk of MI above 10%, a level usually associated with initiation of intervention on risk factors.

CONCLUSIONS

A consistent feature of all analyses was that observed and predicted rates of MI increased in a parallel fashion with increased CART duration, suggesting that the observed increase in risk of MI may at least in part be explained by CART-induced changes in conventional risk factors. These findings provide guidance in terms of choosing lifestyle or therapeutic interventions to decrease those risk factors in much the same way as in persons without HIV infection.

Influence of the blood bacterial load on the meningeal inflammatory response in Streptococcus pneumoniae meningitis

Background

Despite bacteraemia is present in the majority of patients with pneumococcal, little is known about the influence of the systemic infection on the meningeal inflammatory response.

Methods

To explore the role of systemic infection on the meningeal inflammation, experimental meningitis was induced by intracisternal injection of ~1 × 10⁶ CFU Streptococcus pneumoniae, type 3, and the 26 rabbits were either provided with ~1 × 10⁶ CFU S. pneumoniae intravenously at 0 hour ("bacteraemic" rabbits, n = 9), immunized with paraformaldehyde-killed S. pneumoniae for 5 weeks prior to the experiment ("immunized" rabbits", n = 8), or not treated further ("control" rabbits, n = 9). WBC and bacterial concentrations were determined in CSF and blood every second hour during a 16 hours study period together with CSF IL-8 and protein levels. We also studied CSF and blood WBC levels in 153 pneumococcal meningitis patients with and without presence of bacteraemia.

Results

As designed, blood bacterial concentrations were significantly different among three experimental groups during the 16 hours study period (Kruskal Wallis test, P < 0.05), whereas no differences in CSF bacterial levels were observed (P > 0.05). Blood WBC decreased in bacteraemic rabbits between ~10–16 hours after the bacterial inoculation in contrast to an increase for both the immunized rabbits and controls (P < 0.05). The CSF pleocytosis was attenuated in bacteraemic rabbits as compared to the two other groups between 12–16 hours from time of infection (P < 0.017), despite accelerated CSF IL-8 levels in bacteraemic rabbits.

In patients with pneumococcal meningitis, no significant difference in CSF WBC was observed between patients with or without bacteraemia at admission (n = 103, 1740 cells/μL (123–4032) vs. n = 50, 1961 cells/μL (673–5182), respectively, P = 0.18), but there was a significant correlation between CSF and blood WBC (n = 127, Spearman rho = 0.234, P = 0.008).

Conclusion

Our results suggest that a decrease in peripheral WBC induced by enhanced bacteraemia in pneumococcal meningitis results in an attenuated CSF pleocytosis.

A randomized trial to evaluate continuation versus discontinuation of lamivudine in individuals failing a lamivudine-containing regimen: the COLATE trial

BACKGROUND

Lamivudine (3TC) therapy can cause the emergence of M1841/V. Previous studies suggest a higher fidelity of the mutant reverse transcriptase and lower replication capacity of the mutant virus. No data exist from clinical comparative studies evaluating the benefit of M1841/V in patients receiving combination antiretroviral therapy (cART).

METHODS

HIV-1-infected adults failing a 3TC-containing regimen were randomized to continue (On-3TC) or discontinue 3TC (Off-3TC) whilst receiving cART. The primary efficacy measure was the log10 average-area-under-the-curve-minus-baseline reduction in HIV RNA over 48 weeks. Cryopreserved plasma samples from patients with baseline and > or =1 follow-up sample with HIV RNA >500 copies/ml were sequenced for a nucleotide distances substudy. Evolutionary distances were compared between treatment arms and between viruses with and without M1841/V.

RESULTS

The overall 48-week log10 HIV RNA change was -1.4 (95% CI: -1.6, -1.1) for On-3TC (n=65) and -1.5 (95% CI: -1.7, -1.2) for Off-3TC (n=66; P=0.51). No difference was seen in the magnitude of the CD4+ T-cell count increases (median increase: 87 vs 76 cells/ml for 3TC vs Off-3TC, respectively). Thirty-seven patients had baseline and follow-up sequencing. Overall, there were 1.2 (95% CI: -2.2, 4.6) more nucleotide substitutions from baseline for Off-3TC patients (P=0.50), and 10.7 (95% CI: 7.5, 14.0) fewer nucleotide changes in viruses containing M18411V (P<0.0001).

CONCLUSION

This study found no added virological or immunological benefit of continuing 3TC in patients on cART harbouring M1841/V. Evolutionary distances from baseline were larger in viruses that did not contain M1841/V. More discernable benefits may be seen in patients with fewer drug options as potent cART may eclipse a benefit of M1841/V in COLATE.

Is there evidence for an increase in the death rate from liver-related disease in patients with HIV?

BACKGROUND

Increases in deaths due to liver-related disease (LRD) among HIV-infected individuals have been reported although the influence of combination antiretroviral therapy (cART) on LRD is controversial.

AIMS

To determine changes over time in the death rate from LRD and if longer exposure to cART was associated with an increased death rate from LRD in 10 937 patients from EuroSIDA, an observational longitudinal cohort study.

RESULTS

A total of 184 (1.7%) died from LRD during 52 236 person-years of follow-up (PYFU). The death rate from LRD declined from 6.9 per 1000 PYFU before 1995 [95% confidence interval (CI), 3.9-9.9] to 2.6 at/after 2004 (95% CI, 1.6-4.0). When the current CD4 cell count and other factors were taken into account, there was a 13% increase in the death rate from LRD per year (95% CI, 5-20%, P = 0.0008). In patients who had started cART, there was a 12% increase in the death rate from LRD per additional year exposure to cART (95% CI, 4-20%, P = 0.022) after adjustment for current CD4 cell count and other factors.

CONCLUSIONS

Death rates from LRD appeared to decrease across Europe. However after adjustment for the current CD4 cell count, and therefore increases in CD4 cell counts in patients taking cART, there was a significant increase over time in death rates from LRD. In patients with similar CD4 cell counts, longer exposure to cART was associated with an increased death rate from LRD. This may be due to direct liver toxicity of antiretrovirals, progression of liver disease due to hepatitis B virus or hepatitis C virus over time as patients survive longer, or some other factor.

Are Specific Antiretrovirals associated with an Increased Risk of Discontinuation due to Toxicities or Patient/Physician Choice in patients with Hepatitis C Virus Coinfection?

Background

Liver damage associated with hepatitis C (HCV) may influence the likelihood of experiencing discontinuation due to toxicities or patient/physician choice (TOXPC) in patients taking combination antiretroviral therapy (cART). Little information to address this concern is available from clinical trials as patients with HCV are often excluded.

Aims

To compare incidence rates of discontinuation due to TOXPC associated with specific antiretrovial drugs in patients with or without HCV.

Patients/methods

A total of 4929 patients from EuroSIDA under follow-up from January 1999 on a specific nucleoside pair (zidovudine/lamivudine, didanosine/stavudine, stavudine/lamivudine, or other) with a third drug (abacavir, nelfinavir, indinavir, nevirapine, efavirenz, lopinavir/ ritonavir or other boosted-protease inhibitor (PI)-containing regimen) and with known HCV serostatus were studied for the incidence of discontinuation of any nucleoside pair or third drug due to TOXPC. Incidence rate ratios were derived from Poisson regression models.

Results

In total 1358 patients had HCV (27.5%). During 12 799 person-years of follow-up there were 2141 discontinuations due to TOXPC for nucleoside pairs and 2501 for third drugs. The incidence of discontinuation due to TOXPC was consistently higher in patients with HCV after stratification by nucleoside pair or third drug. After adjustment for CD4+ count, gender, exposure group, time on HAART, region and treatment regimen, there were few differences in the rate of discontinuation due to TOXPC in those with HCV compared with those without for any nucleoside pairs or third drugs. Similar results were seen when concentrating on discontinuation due to toxicities alone.

Conclusions

Although patients with HCV generally had higher rates of discontinuation due to TOXPC compared with patients without HCV, there was little evidence to suggest that this was associated with any specific nucleoside pair or third drug used as part of cART. Our results do not suggest that any specific component of cART is more poorly tolerated in patients with HCV or that the presence of HCV should influence the choice between antiretrovirals used as part of a cART regimen.

Predictors of Hypertension and Changes of Blood Pressure in HIV-Infected Patients

Objective

We assessed predictors of changes in systolic (SBP) and diastolic (DBP) blood pressure during follow-up and of the development of hypertension in HIV-infected individuals.

Methods

International cohort collaborative study (D:A:D) of established prospective cohorts of HIV-1-infected patients. Longitudinal analysis of changes in blood pressure (BP) was performed using mixed effects models in 17170 patients. Predictors of development of hypertension during follow-up (systolic BP ≥140 and/or diastolic BP ≥90 mmHg or initiation of antihypertensive treatment) were assessed using Cox models in 8 984 patients with a normal BP level at baseline.

Results

73548 BP measurements with a median of 4 per patient (interquartile range [IQR]: 2–6) were recorded over a median follow-up of 2.3 years (IQR: 1.5–2.6). Risk factors significantly associated with a development of higher systolic BP and diastolic BP (differences ≥5 mmHg and P-values <0.001) during follow-up were: older age, male sex, higher body mass index (BMI) and use of BP-lowering drugs. In patients with normal BP at baseline, 1186 developed hypertension for an incidence of 72.1 per 1000 person-years (95% confidence interval: 68.2–76.0). Factors associated with development of hypertension were: male sex, higher BMI, older age, higher BP at baseline, high total cholesterol and clinical lipodystrophy. Cumulative duration of exposure to nucleoside reverse transcriptase inhibitors ( P=0.75), protease inhibitors ( P=0.92) as well as type of antiretroviral treatment at baseline ( P=0.18) were not associated with a higher risk of hypertension. Cumulative duration of exposure to non-nucleoside reverse transcriptase inhibitors (NNRTIs) was significantly associated with lower risk of hypertension (hazard ratio=0.78 and 0.67 for those treated ≤10 months and >10 months compared with no exposure; P=0.005).

Conclusions

Increased blood pressure in HIV-infected individuals is associated with established risk factors for hypertension. There was no evidence for an independent deleterious effect of any class of antiretroviral drugs on BP, although the use of NNRTIs was associated with a lower risk of development of hypertension.

Thymidine Analogue Mutation Profiles: Factors Associated with Acquiring Specific Profiles and their Impact on the Virological Response to Therapy

Background

Studies have suggested that HIV-1 may develop thymidine analogue mutations (TAMs) by one of two distinct pathways – the TAM1 pathway (including mutations 41L, 210W and 215Y) or the TAM2 pathway (including mutations 67N, 70R and 219E/Q) – under the pressure of a not fully suppressive thymidine-analogue-containing regimen.

Methods

Frozen plasma samples stored in the EuroSIDA repository were selected and sent to two central laboratories for genotypic analysis. We considered 733 patients with at least one genotypic test showing ≥1 TAMs (the first of these tests in chronological order was used). TAM1 and TAM2 genotypic profiles were defined in accordance with previous literature. Statistical modelling involved logistic regression and linear regression analysis for censored data.

Results

The observed frequencies of patterns classifiable as TAM1 or TAM2 profiles were markedly higher than the probabilities of falling into these classifications by chance alone. The chance of detecting a TAM2 profile increased by 25% per additional year of exposure to zidovudine. We found that mutations 67N and 184V were not associated with a particular TAM profile. In the presence of TAM2 profiles, the adjusted mean difference in the 6-month viral reduction was 0.96 log10 copies/ml (95% confidence interval: 0.20; 1.73) higher in patients who started stavudine-containing regimens instead of zidovudine-containing regimens.

Conclusions

This study provides evidence that the suggested TAM clustering is a real phenomenon and that it may be driven by which thymidine analogue the patients has used. In patients with TAM2-resistant viruses, stavudine appears to retain greater viral activity than zidovudine.