Tobacco, alcohol, cannabis, and illicit drug use and their association with CD4/CD8 cell count ratio in people with controlled HIV: a cross-sectional study (ANRS CO3 AQUIVIH-NA-QuAliV)

BACKGROUND

To evaluate drug use (alcohol, tobacco, cannabis and other drugs) and its association with mean CD4/CD8 T cell count ratio, a marker of chronic inflammation, in virally suppressed people living with HIV-1 (PLWH) in Nouvelle Aquitaine, France.

METHODS

A multi-centric, cross-sectional analysis was conducted in 2018-19 in the QuAliV study-ANRS CO3 AQUIVIH-NA cohort. Tobacco, alcohol, cannabis, and other drug use (poppers, cocaine, amphetamines, synthetic cathinones, GHB/GBL) were self-reported. CD4 and CD8 T cell counts and viral load measures, ± 2 years of self-report, and other characteristics were abstracted from medical records. Univariable and multivariable linear regression models, adjusted for age, sex, HIV risk group, time since HIV diagnosis, and other drug use were fit for each drug and most recent CD4/CD8 ratio.

RESULTS

660 PLWH, aged 54.7 ± 11.2, were included. 47.7% [315/660] had a CD4/CD8 ratio of < 1. Their mean CD4/CD8 ratio was 1.1 ± 0.6. 35% smoked; ~ 40% were considered to be hazardous drinkers or have alcohol use disorder; 19.9% used cannabis and 11.9% other drugs. Chemsex-associated drug users' CD4/CD8 ratio was on average 0.226 (95% confidence interval [95% CI] - 0.383, - 0.070) lower than that of non-users in univariable analysis (p = 0.005) and 0.165 lower [95% CI - 0.343, 0.012] in multivariable analysis (p = 0.068).

CONCLUSIONS

Mean differences in CD4/CD8 ratio were not significantly different in tobacco, alcohol and cannabis users compared to non-users. However, Chemsex-associated drug users may represent a population at risk of chronic inflammation, the specific determinants of which merit further investigation.

TRIAL REGISTRATION NUMBER

NCT03296202.

Severe bacterial non-AIDS infections in persons with HIV: the epidemiology and evolution of antibiotic resistance over an 18-year period (2000-2017) in the ANRS CO3 AquiVih-Nouvelle-Aquitaine cohort

BACKGROUND

Severe non-AIDS bacterial infections (SBIs) are one of the leading causes of hospital admissions among persons with HIV (PWH) in regions with high ART coverage.

METHODS

This large prospective cohort study of PWH examined the types of infections, bacterial documentation, and evolution of antibiotic resistance among PWH hospitalized with SBIs over an 18-year period.

RESULTS

Between 2000 and 2017, 459 PWH had at least one SBI with bacterial documentation. Among the 847 SBIs, there were 280 cases of bacteremia, 269 cases of pneumonia, and 240 urinary tract infections. The 1025 isolated bacteria included Enterobacteriaceae (n = 394; mainly Escherichia coli), Staphylococcus aureus (n = 153) and Streptococcus pneumoniae (n = 82). The proportion of S. pneumoniae as the causative agent in pneumonia and bacteremia decreased sharply over time, from 34% to 8% and from 21 to 3%, respectively.The overall antibiotic resistance of S. aureus and S. pneumoniae decreased progressively but it increased for Enterobacteriaceae (from 24% to 48% for amoxicillin-clavulanate, from 4 to 18% for cefotaxime, and from 5% to 27% for ciprofloxacin). Cotrimoxazole prophylaxis was associated with higher nonsusceptibility of S. pneumoniae to amoxicillin and erythromycin, higher nonsusceptibility of Enterobacteriaceae to beta-lactams and fluoroquinolones, and a higher risk of extended-spectrum β-lactamase producing Enterobacteriaceae.

CONCLUSIONS

The bacterial resistance pattern among PWH between 2014 and 2017 was broadly similar to that in the general population, with the exception of a higher resistance profile of Enterobacteriaceae to fluoroquinolones. The use of cotrimoxazole as prophylaxis was associated with an increased risk of antibiotic resistance.

Is the subcutaneous route an alternative for administering ertapenem to older patients? PHACINERTA study

BACKGROUND

Antibiotic administration by subcutaneous (SC) injection is common practice in French geriatric wards as an alternative to the intravenous (IV) route, but few pharmacokinetic/pharmacodynamic data are available. Ertapenem is useful for the treatment of infections with ESBL-producing enterobacteria.

OBJECTIVES

To report and compare ertapenem pharmacokinetic data between IV and SC routes in older persons.

METHODS

Patients >65 years of age receiving ertapenem (1 g once daily) for at least 48 h (IV or SC, steady-state) were prospectively enrolled. Total ertapenem concentrations [residual (C0), IV peak (C0.5) and SC peak (C2.5)] were determined by UV HPLC. Individual-predicted AUC0-24 values were calculated and population pharmacokinetic analyses were performed. Using the final model, a Monte Carlo simulation involving 10 000 patients evaluated the influence of SC or IV administration on the PTA. Tolerance to ertapenem and recovery were also monitored. ClinicalTrials.gov identifier: NCT02505386.

RESULTS

Ten (mean ± SD age=87±7 years) and 16 (age=88±5 years) patients were included in the IV and SC groups, respectively. The mean C0 and C2.5 values were not significantly different between the IV and SC groups (C0=12±5.9 versus 12±7.4 mg/L, P=0.97; C2.5=97±42 versus 67±41 mg/L, P=0.99). The mean C0.5 was higher in the IV group compared with the SC group (C0.5=184±90 versus 51±66 mg/L, P=0.001). The mean individual AUCs (1126.92±334.99 mg·h/L for IV versus 1005.3±266.0 mg·h/L for SC, P=0.38) and PTAs were not significantly different between groups. No severe antibiotic-related adverse effects were noted.

CONCLUSIONS

SC administration of ertapenem is an alternative to IV administration in older patients.

Implementation of infliximab standardized doses after pharmacokinetic modelization in a cohort of patients with Crohn's disease

BACKGROUND

According to infliximab (IFX) license in Crohn's disease (CD), infusion doses are based on patient's body-weight. Dose banding providing standardized doses (SD) has been implemented in parenteral chemotherapy in order to optimize aseptic unit capacity and reduce drug expenditure, duration of hospital stay and costs without decreasing efficacy.

MATERIAL AND METHOD

The first part was a single-center retrospective analysis of consecutive CD patients receiving IFX maintenance therapy to determine standardized doses covering more than 50% of infusions. The second part was a prospective cohort study assessing the impact of SD compared to body-weight doses (BWD) on admission duration and costs.

RESULTS

Six IFX SD covering more than 90% of infusion doses were implemented for dose banding. According to the Monte-Carlo simulation, there was no significant difference between IFX SD and BWD maintenance regimens. When assessed prospectively in 116 patients (75 patients treated with SD and 41 with BWD) corresponding to 128 infusions, hospitalization duration was shortened by 70 min per patient (p < 0.001).

CONCLUSION

According to a pharmacokinetic model, IFX SD has a pharmacokinetic profile close to BWD and is associated with reduced length of hospitalization in a cohort of patients with CD. IFX SD implementation could optimize infusion units functioning and, save time and costs without decreasing efficacy.

Higher than standard dosing regimen are needed to achieve optimal antibiotic exposure in critically ill patients with augmented renal clearance receiving piperacillin-tazobactam administered by continuous infusion

PURPOSE

To determine whether augmented renal clearance (ARC) impacts negatively on piperacillin-tazobactam unbound concentrations in critically ill patients receiving 16 g/2 g/day administered continuously.

MATERIAL AND METHODS

Fifty nine critically ill patients without renal impairment underwent 24-h creatinine clearance (Cr_CL) measurement and therapeutic drug monitoring during the first three days of antimicrobial therapy by piperacillin-tazobactam. The main outcome was the rate of piperacillin underexposure, defined by at least one of three samples under 16 mg/L. Monte Carlo simulation was performed to predict the distribution of piperacillin concentrations for various Cr_CL and minimal inhibitory concentration (MIC) values.

RESULTS

The rate of piperacillin underexposure was 19%, significantly higher in ARC patients (0 vs. 31%, p = .003). A threshold of Cr_CL ≥ 170 mL/min had a sensitivity and specificity of 1 (95%CI: 0.79-1) and 0.69 (95%CI: 0.61-0.76) to predict piperacillin underexposure. In ARC patients, a 20 g/2.5 g/24 h PTZ dosing regimen was associated with the highest probability to reach the 16 mg/L empirical target, without risk of excessive dosing.

CONCLUSIONS

When targeting a theoretical MIC at the upper limit of the susceptibility range, the desirable target (100%fT_>16) may not be achieved in patients with Cr_CL ≥ 170 mL/min receiving PTZ 16 g/2 g/day administered continuously.

Association between augmented renal clearance, antibiotic exposure and clinical outcome in critically ill septic patients receiving high doses of β-lactams administered by continuous infusion: a prospective observational study

This study assessed whether augmented renal clearance (ARC) impacts negatively on antibiotic concentrations and clinical outcomes in patients treated by high-dose β-lactams administered continuously. Over a 9-month period, all critically ill patients without renal impairment treated by one of the monitored β-lactams for a documented infection were eligible. During the first 3 days of antibiotic therapy, every patient underwent 24-h CL_Cr measurements and therapeutic drug monitoring. The main outcome was the rate of β-lactam underdosing, defined as a free drug concentration <4 × MIC of the known pathogen. Secondary outcomes were rates of subexposure for β-lactams and therapeutic failure. The performance of CL_Cr in predicting underdosing was assessed by a ROC curve, and multivariable logistic regression was performed to determine risk factors for subexposure and therapeutic failure. A total of 79 patients were included and 235 samples were analysed. The rate of underdosing_<4×MIC was 12%, with a significant association with CL_Cr (P <0.0001). A threshold of CL_Cr ≥ 170 mL/min had a sensitivity and specificity of 0.93 (95% CI 0.77-0.99) and 0.65 (95% CI 0.58-0.71) for predicting β-lactam underdosing_<4×MIC. Mean CL_Cr values ≥170 mL/min were significantly associated with subexposure_<4xMIC [OR = 10.1 (2.4-41.6); P = 0.001]. Patients with subexposure_<4×MIC presented higher rates of therapeutic failure [OR = 6.3 (1.2-33.2); P = 0.03]. Mean CL_Cr values ≥170 mL/min remain a risk factor for subexposure to β-lactams despite high doses of β-lactams administered continuously. β-Lactam subexposure was associated with higher rates of therapeutic failure in septic critically ill patients.

Pre-dose plasma concentration monitoring of mycophenolate mofetil in patients with autoimmune diseases

AIM

To date, neither the benefit of mycophenolic acid (MPA) therapeutic drug monitoring (TDM), the prodrug of mycophenolate mofetil (MMF), nor the optimal monitoring technique have been established in autoimmune diseases. This study was undertaken to confirm, in a cohort of new patients, the plasma MPA thresholds previously published in patients with systemic lupus erythematosus (SLE) or vasculitis.

METHODS

MPA areas under the concentration-time curves between 0 and 12 h, 12 h trough concentrations and pre-dose concentrations (C0 ) were determined for 23 patients with SLE and 21 with systemic vasculitis. The relationship between patients' pharmacokinetic (PK) variables and their clinical outcomes during follow-up were analyzed.

RESULTS

In both autoimmune diseases, at PK assessment, median MPA C0 for patients with uncontrolled disease was significantly lower than that of patients with stable disease or in remission, 1.6 mg l(-1) (IQR 0.9-2.1 mg l(-1)) vs. 2.95 mg l(-1) (IQR 1.38-3.73 mg l(-1)) for SLE (P = 0.048) and 1.55 mg l(-1) (IQR 0.98-2.18 mg l(-1)) vs. 3 mg l(-1) (IQR 2.2-4.4 mg l(-1)) for vasculitis (P = 0.016). According to our receiver operating characteristics curve analysis, a C0 threshold of 2.5-3 mg l(-1) was best able to discriminate a flare (SLE: 88% sensitivity, 80% specificity; vasculitis: 100% sensitivity, 90% specificity). Patients with C0 ≥ 2.5-3 mg l(-1) at inclusion had better clinical outcomes during the 12 months following PK assessment.

CONCLUSION

Provided that the benefit of TDM in patients with autoimmune diseases could be confirmed by randomized, controlled trials, it might be based on the C0 measured approximately 12 h post-dose.

Pravastatin in HIV-Infected Patients Treated with Protease Inhibitors: A Placebo-Controlled Randomized Study

PURPOSE

The objectives of the study were to assess the effects of pravastatin on plasma HIV RNA, lipid parameters, and protease inhibitor (PI) concentrations in patients treated with PI-containing regimens and with total cholesterol (TC) > or = 5.5 mmol/L.

METHOD

A clinical trial including patients randomized to receive pravastatin or matching placebo for 12 weeks was implemented.

RESULTS

Twelve patients were included in the pravastatin group and 9 in the placebo group. At week 12 (W12), no patient had experienced virological failure. Between week 0 (W0) and W12, the median differences for TC were -1.4 mmol/L in the pravastatin group and +0.2 mmol/L in the placebo group (p = .005); for LDL, they were -1.0 mmol/L and +0.3 (p = .007), respectively. A significant decrease of the PI concentration (12 hours after administration) ratio W12 - W0/W0 was noticed in the pravastatin group (-0.2 [interquartile range, -0.3 to -0.1] as compared with the placebo group (0.1 [IQR, 0.0 to 0.3]) (p = .03). When the study was restricted to patients treated with lopinavir/ritonavir, a decrease from 3.8 microg/mL at baseline to 2.9 mug/mL at W12 was noticed in the pravastatin arm (p = .04) but not in the control arm (p = 1.00). No clinical adverse event reached a severity of grade 3.

CONCLUSION

We observed in this study that the use of pravastatin in PI-treated patients was not associated with major change in the plasma HIV RNA on 12 weeks of follow-up. However, we found a trend of decrease of the trough PI concentration at W12, suggesting a possible drug-drug interaction of pravastatin on PI metabolism.

In vivo interactions of continuous flucloxacillin infusion and high-dose oral rifampicin in the serum of 15 patients with bone and soft tissue infections due to Staphylococcus aureus - a methodological and pilot study

Background

Increased antibiotic resistance against Staphylococcus aureus and low penetration into bone requires regimen optimization of available drugs.

Methods

We evaluate pharmoacokinetic and pharmacodynamic parameters (PK/PD) as well as in vivo interactions of continuous flucloxacillin 12 g/d administration combined with high dose oral rifampicin 600 mg bid in the serum of 15 adult patients with bone and soft tissue infections. We use the patient’s own serum directed against his own isolated S. aureus strain to reproduce in vivo conditions as closely as possible.

Results

The continuous flucloxacillin infusion constantly generated plasma free drug levels largely exceeding the serum minimal inhibitory concentrations (mean 74-fold). Combination with rifampicin significantly increased flucloxacillin levels by 44.5%. Such an increase following rifampicin introduction was documented in 10/15 patients, whereas a decrease was observed in 1/15 patients. Finally, all infections were cured and the combination was well tolerated.

Conclusions

In this in vivo methodological pilot study among adult patients with orthopaedic infections due to S. aureus, we describe a new method and reveal substantial but inconsistent interactions between flucloxacillin and rifampicin, of which the clinical significance remains unclear.

Chemical stability of azacitidine suspensions for injection after cold-chain reconstitution of powder and storage

PURPOSE

The 72-hour chemical stability of refrigerated syringes of azacitidine suspension prepared via a cold-chain method is investigated.

METHODS

Three 25-mg/mL azacitidine suspensions were prepared from different lots of powdered drug. The suspensions were stored in 2-mL polypropylene syringes at 2-8 °C and protected from light. The concentrations of azacitidine and the mean area under the concentration-time curve (AUC) values for its degradation products were determined after 0, 1, 2, 3, 4, 6, 8, 12, 24, 48, and 72 hours using high-performance liquid chromatography with ultraviolet detection.

RESULTS

The degradation process was slow during the first 48 hours and then accelerated. During the first 48 hours of storage, 4.23% of the azacitidine was lost relative to the mean concentration measured at time zero, which complied with International Conference on Harmonisation (ICH) guidance specifying a maximum change of 5% from the initial measured value. Two degradation products were present immediately after syringe preparation; N-formylribosylguanylurea formed rapidly (as indicated by a 35.62% increase from the baseline AUC in the first 12 hours), whereas ribosylguanylurea formation occurred more slowly (a 7.69% mean increase from the baseline AUC at 12 hours) but then rapidly accelerated. The study results indicate that properly prepared azacitidine syringes for injection can be administered up to two days later while maintaining conformance with ICH stability standards.

CONCLUSION

Azacitidine 25-mg/mL suspensions reconstituted with refrigerated water (2-8 °C) and stored in propylene syringes were chemically stable during the first 48 hours when stored protected from light at 2-8 °C.

Diffusion of Oral and Intravenous 400 mg Once-Daily Moxifloxacin into Lung Tissue at Pharmacokinetic Steady-State

The degree of penetration of an antibiotic into the infection site is an important factor for its therapeutic efficacy, particularly in respiratory tract infections. In the present study, we examined the lung tissue diffusion of moxifloxacin at a dose of 400 mg administered intravenously or orally once-daily, and the results were correlated to microbiological data to estimate the clinical efficacy of moxifloxacin in lower community-acquired respiratory infections. This was a prospective, randomized, parallel-group trial, open-label, single-center study. Patients undergoing lung surgery for bronchial cancer which necessitates the removal of an anatomical piece of lung tissue were randomized into twelve treatment groups, dependent upon the time of surgery and the moxifloxacin formulation, i.v. or oral, administered. During surgery, one blood sample was taken at the time of tissue collection to determine moxifloxacin plasma concentration. At the same time, tissue samples were taken by pulmonary exeresis. A validated new high performance liquid chromatography assay was used to determine moxifloxacin concentrations in plasma and lung tissue. A total of 49 patients (25 for i.v. administration, 24 for oral administration, 44 men and 5 women, mean age, 61 years, mean body weight, 72 kg, mean creatinine clearance was 84 ml/min/1.73 m2) were enrolled. The mean +/- SD steady-state moxifloxacin ratios between lung and plasma concentrations were respectively: 3.53 +/- 1.89 and 4.36 +/- 1.48 for i.v. and oral administration. The mean steady-state moxifloxacin maximal lung concentrations (Cmax) were respectively 12.37 microg/g and 16.21 microg/g for i.v. and oral administration. Moxifloxacin both intravenously and orally exhibits high penetration in lung tissue, with tissue concentrations far above the MIC90s for most of the susceptible pathogens commonly involved, thus underlining its suitability for the treatment of community-acquired, lower respiratory tract infections.

Alveolar diffusion and pharmacokinetics of linezolid administered in continuous infusion to critically ill patients with ventilator-associated pneumonia

OBJECTIVES

This study aimed to determine the steady-state serum and alveolar concentrations of linezolid administered by continuous infusion to critically ill patients with ventilator-associated pneumonia (VAP).

PATIENTS AND METHODS

This was a prospective, open-label study performed in an intensive care unit and research ward in a university hospital. Twelve critically ill adult patients with VAP received 600 mg of linezolid as a loading dose followed by 1200 mg/day by continuous infusion. After 2 days of therapy, the steady-state serum and alveolar (collected by a mini-bronchoalveolar procedure) concentrations of linezolid were determined by HPLC.

RESULTS

The median (IQR) serum and epithelial lining fluid (ELF) linezolid concentrations at steady state (C(ss)) were 7.1 (6.1-9.8) and 6.9 (5.8-8.6) mg/L, respectively, and the median (IQR) AUC (AUC(0-24)) values were 169 (146-235) and 164 (139-202) mg · h/L, respectively, corresponding to a median (IQR) linezolid alveolar diffusion of 97% (80%-108%).

CONCLUSIONS

Our study shows that the continuous infusion of 1200 mg of linezolid daily in critically ill patients with VAP provides satisfactory pharmacokinetic results, with a linezolid alveolar diffusion of 100% and concentrations exceeding almost twice the susceptibility breakpoint for Staphylococcus aureus (4 mg/L) in both serum and ELF for 100% of the time. However, the clinical benefit of continuous infusion in comparison with standard intermittent infusion is still to be determined.

A sensitive liquid chromatography coupled with mass spectrometry method for the intracellular and plasma quantification of raltegravir after solid-phase extraction

INTRODUCTION

Liquid chromatography coupled with mass spectrometry for the quantification of raltegravir in human plasma and peripheral blood mononuclear cells has been developed.

METHODS

Sample preparations were based on a fully automated solid-phase extraction process. Mass spectrometric data were acquired in a single-ion monitoring method. Raltegravir and quinoxaline, the internal standard, were well separated in a gradient mode over 15 min.

KEY FINDINGS

Validation study exhibited excellent linearity, with good intra- and inter-day precision and accuracy.

CONCLUSIONS

The assay was successfully applied to the raltegravir quantification in HIV-infected patients.

Pharmacokinetics of free ertapenem in critically ill septic patients: intermittent versus continuous infusion

BACKGROUND

The aim of this paper was to compare the pharmacokinetic and pharmacodynamic (PK/PD) parameters of continuous (CI) and intermittent infusion (ITI) of ertapenem into critically ill patients with severe abdominal infections.

METHODS

Twenty septic patients hospitalized in a university hospital intensive care unit were enrolled in the study. Half of the patients received ertapenem as an ITI 1 g bolus once daily, and the other half of the patients received the same dose via CI over 24 h following a 1-g loading dose. Blood was drawn 1, 12 and 24 h after terminating ITI or on days 2, 3 and 5 after starting CI for each patient. After centrifugation, the drawn blood was frozen at -80 °C until being examined by high-performance liquid-chromatography analysis.

RESULTS

Median serum-free ertapenem concentrations were as follows: ƒCmax = 98.9 mg/L and ƒCmin = 2.5 mg/L for ITI, and ƒCss=15.9 mg/L for CI. The ITI and CI median total clearance and volumes of distribution were 2.2 L/h vs. 2.5 L/h and 15.4 L vs. 21.0 L, respectively. The ertapenem MIC ranges were as follows: Escherichia coli (0.006 to 0.5 mg/L), Enterobacter cloacae (0.023 to 0.5 mg/L), Klebsiella oxytoca (0.023 to 0.5 mg/L), Staphylococcus aureus (0.38 to 3 mg/L), Streptococcus viridians (0.38 to 3 mg/L) and Enterococcus faecalis (0.38 to 3 mg/L). ITI and CI provided steady-state serum-free ertapenem concentrations constantly above the MIC for all bacteria.

CONCLUSION

Ertapenem exhibited satisfactory PK/PD parameters and achieved serum-free concentrations 100% of the time, above even the high MIC of extracellular pathogens normally encountered during severe abdominal infections. CI administration resulted in equally effective PK/PD parameters as ITI in normal weight, good renal-function patients.

Steady-state mycophenolate mofetil pharmacokinetic parameters enable prediction of systemic lupus erythematosus clinical flares: an observational cohort study

Introduction

The aim of this study was to determine whether mycophenolate mofetil (MMF) pharmacokinetics (PK) under combined MMF and prednisone remission-maintenance therapy can predict systemic lupus erythematosus (SLE) clinical flares.

Methods

At inclusion, steady-state PK parameters of the MMF active form, mycophenolic acid (MPA), and its glucuronide metabolite (MPAG) were determined for 25 stable SLE patients without renal manifestations. Disease activity was assessed during 6 months of follow-up. Potential relationships between those entry MMF-PK variables and clinical outcome were analyzed.

Results

MMF controlled disease activity in 17 patients (successes) and failed to do so for 8 others (failures). For failures and successes, respectively, entry MPA areas under the time-concentration curve between 0 and 12 hours (AUC_{0-12 h}) (medians: 37.7 vs 73.1 mg/h/L, P = 0.003) and MPA 12-hour trough concentrations (C_{12 h}) (medians: 1.5 vs 3.7 mg/L, P = 0.008) were significantly lower, and inclusion MPAG/MPA C_{12 h} ratios (medians: 18.7 vs 10.2, P = 0.02) were significantly higher. According to our receiver operating characteristics curve analysis, MPA C_{12 h} was best able to discriminate a flare during follow-up (93% sensitivity, 85% specificity). A 3-mg/L cut-off had 92% negative-predictive value for developing a flare during follow-up.

Conclusions

For our SLE patients without renal manifestations, clinical flares developing under maintenance therapy were associated with steady-state inclusion MPA C_{12 h} < 3 mg/L.

An in vitro study of epoetin beta intravenous injection site at the end of hemodialysis

The aim of this study (SITEPO) is to evaluate the influence of the intravenous injection site (drip chamber injection site, venous injection site or venous fistula needle) on plasma concentration of epoetin beta (Neorecormon, Roche), a recombinant Human Erythropoietin (rHuEPO), at the end of in vitro hemodialysis sessions. No practical administration guidelines are available. Twenty 1-h dialysis sessions are performed. Before each dialysis, the circuit is filled with 270ml, of heparinized total human blood whose hematocrit is adjusted to 35%. A common dosage of epoetin beta in clinical practice (3000IU) is studied for the three injection sites and for reference experiments in which rHuEPO is not injected into the dialysis circuit. Plasma concentrations of erythropoietin are measured by ELISA. The physiologically endogenous erythropoietin concentration is systematically determined and removed from the total epoetin beta concentration. Average epoetin beta plasma levels returned are not significantly different between the three injection sites and no significant rHuEPO loss is observed after injection into the drip chamber, the venous injection site and the venous fistula needle compared with reference experiments. The three intravenous injection sites of rHuEPO can be used at the end of dialysis without significant epoetin beta loss.

Impact of ribavirin plasma level on sustained virological response in patients treated with pegylated interferon and ribavirin for chronic hepatitis C

BACKGROUND

The main goal of therapy in hepatitis C virus (HCV) infection is to achieve a sustained virological response (SVR). However, the impact of the pharmacological properties of ribavirin on the SVR has not been fully investigated.

AIM

To evaluate, through a prospective study, the association between ribavirin plasma level and SVR response in HCV patients treated with pegylated interferon (PEG-IFN) and ribavirin.

PATIENTS AND METHODS

Patients treated with PEG-IFN and ribavirin had plasmatic ribavirin dosage at weeks 4 and 12. SVR was evaluated 6 months after the end of treatment.

RESULTS

At week 4, a strong correlation was found between HCV-RNA and C(min) of ribavirin plasma level (r = -0.376, P = 0.002) and AUC(0-->12h) of ribavirin plasma level (r = -0.277, P = 0.018). At week 12, a strong correlation was found between HCV-RNA and C(min) of ribavirin plasma level (r = -0.384, P < 0.0001) and AUC(0-->12h) of ribavirin plasma level (r = -0.257, P = 0.002). In genotype 1 patients, AUC(0-->12h) ribavirin and C(min) were significantly correlated with negative HCV-RNA at week 12 and SVR. In the multiple logistic regression model, the only factor independently associated with SVR in genotype 1 patients was negative HCV-RNA at week 12.

CONCLUSION

C(min) of ribavirin at weeks 4 and 12 was significantly higher in sustained virological responders compared with relapser or nonresponder patients. However, in genotype 1 patients, plasma ribavirin level at weeks 4 and 2 was not associated with SVR.

Virological and immunological response in HIV-1-infected patients with multiple treatment failures receiving raltegravir and optimized background therapy, ANRS CO3 Aquitaine Cohort

BACKGROUND

The efficacy of raltegravir plus optimized background therapy (OBT) has been demonstrated for antiretroviral (ARV)-experienced HIV-1-infected patients in randomized clinical trials. We studied viro-immunological response, pharmacokinetic parameters and genotypic test results in an observational cohort of multiple ARV class-experienced patients starting a raltegravir-based regimen.

METHODS

Already enrolled ANRS CO3 Aquitaine Cohort patients with virological failure were included in this study after starting a raltegravir-based regimen (400 mg twice a day, week 0). Virological success was defined by the plasma HIV-1 RNA level [viral load (VL)] <2.7 log(10) copies/mL at week 12 and <1.7 log(10) copies/mL at week 24. One patient was excluded from further analysis (no follow-up after week 4).

RESULTS

Fifty-one patients [male/female = 43/8, median age = 48 (interquartile range = 43, 55) years] were included. At week 0, median CD4 count was 244 (110; 310)/mm(3) and median VL was 4.2 (3.6, 4.7) log(10) copies/mL. At week 24, 39 (78%) patients experienced virological success: 4 (44%), 14 (82%) and 21 (87%) patients with a genotypic sensitivity score <1, > or =1 and <2 and > or =2 (P = 0.02), respectively. Raltegravir-related mutations emerged in 9 of 11 failing patients (82%): Q148H/R (n = 5), N155S/H (n = 3) and S230N (n = 1). Median CD4 increases from week 0 to week 4 and week 24 were 28 (-4, 85) and 57 (0, 156) cells/mm(3), respectively. A poor immune response was independently associated with a lower VL decline (week 0 to week 12) [odds ratio (OR): 3.5, 95% confidence interval (CI): 1.4, 8.4, for 1 log(10) less] and CD4+% at baseline (OR: 2.6, 95% CI: 0.97, 8.3, for 10% lower).

CONCLUSIONS

Raltegravir plus OBT provided a good virological success rate in highly pre-treated patients under clinical routine conditions.

Alternative methods to analyse the impact of HIV mutations on virological response to antiviral therapy

Background

Principal component analysis (PCA) and partial least square (PLS) regression may be useful to summarize the HIV genotypic information. Without pre-selection each mutation presented in at least one patient is considered with a different weight. We compared these two strategies with the construction of a usual genotypic score.

Methods

We used data from the ANRS-CO3 Aquitaine Cohort Zephir sub-study. We used a subset of 87 patients with a complete baseline genotype and plasma HIV-1 RNA available at baseline and at week 12. PCA and PLS components were determined with all mutations that had prevalences >0. For the genotypic score, mutations were selected in two steps: 1) p-value < 0.01 in univariable analysis and prevalences between 10% and 90% and 2) backwards selection procedure based on the Cochran-Armitage Test. The predictive performances were compared by means of the cross-validated area under the receiver operating curve (AUC).

Results

Virological failure was observed in 46 (53%) patients at week 12. Principal components and PLS components showed a good performance for the prediction of virological response in HIV infected patients. The cross-validated AUCs for the PCA, PLS and genotypic score were 0.880, 0.868 and 0.863, respectively. The strength of the effect of each mutation could be considered through PCA and PLS components. In contrast, each selected mutation contributes with the same weight for the calculation of the genotypic score. Furthermore, PCA and PLS regression helped to describe mutation clusters (e.g. 10, 46, 90).

Conclusion

In this dataset, PCA and PLS showed a good performance but their predictive ability was not clinically superior to that of the genotypic score.

Virological Response to Darunavir/Ritonavir-Based Regimens in Antiretroviral-Experienced Patients (PREDIZISTA Study)

Background

We assessed the association of baseline HIV-1 mutations, phenotypic sensitivity and pharmacokinetics with virological failure (VF) at week 12 (W12) after onset of a darunavir/ritonavir (DRV/r)-based regimen in a cohort of 67 antiretroviral-experienced HIV-patients failing on highly active antiretroviral therapy (HAART).

Methods

VF was defined as HIV RNA >2.3 log10copies/ml at W12. HIV reverse transcriptase and protease sequencing was performed at W0; mutations with a P-value <0.25 in univariable analyses were used for a backward selection to find the best mutation set for VF prediction. Genotypic and phenotypic sensitivity scores were calculated and virtual phenotype predicted fold change (FC) assessed. DRV Cmin, Cmax, AUC0→12 h and genotypic inhibitory quotient (GIQ) were determined.

Results

Patients had a median of 15 previous treatments for 10 years. Median W0 values included a T-cell count of 129 cells/μl, 4.7 log10 HIV RNA copies/ml, four major protease and six nucleoside reverse transcriptase inhibitor resistance mutations. At W12, median HIV RNA decrease was -2.1 log10 copies/ml with a gain of +67 CD4+ T-cells/μl; 40% of patients failed. We determined the genotypic score I13V+V32I+L33F/I/V+E35D+ M36I/L/V+I47V+F53L+I62V According to <4, 4–5 and >5 mutations, failure occurred in 11%, 48% and 100% of patients. Failure was associated with CDC stage, baseline CD4+ T-cell count, number of major protease inhibitor resistance mutations, FC and DRV/r score. Pharmacokinetics were not associated with failure, but GIQ was.

Conclusion

At W12, 60% of heavily pretreated patients responded on DRV/r-based HAART. Genotypic and phenotypic information constituted the main virological response determinant in patients with optimal drug concentrations.

Virological response to darunavir/ritonavir-based regimens in antiretroviral-experienced patients (PREDIZISTA study)

BACKGROUND

We assessed the association of baseline HIV-1 mutations, phenotypic sensitivity and pharmacokinetics with virological failure (VF) at week 12 (W12) after onset of a darunavir/ritonavir (DRV/r)-based regimen in a cohort of 67 antiretroviral-experienced HIV-patients failing on highly active antiretroviral therapy (HAART).

METHODS

VF was defined as HIV RNA >2.3 log10copies/ml at W12. HIV reverse transcriptase and protease sequencing was performed at WO; mutations with a P-value <0.25 in univariable analyses were used for a backward selection to find the best mutation set for VF prediction. Genotypic and phenotypic sensitivity scores were calculated and virtual phenotype predicted fold change (FC) assessed. DRV Cmin, Cmax, AUC(0-->12 h) and genotypic inhibitory quotient (GIQ) were determined.

RESULTS

Patients had a median of 15 previous treatments for 10 years. Median W0 values included a T-cell count of 129 cells/microl, 4.7 log10 HIV RNA copies/ml, four major protease and six nucleoside reverse transcriptase inhibitor resistance mutations. At W12, median HIV RNA decrease was -2.1 log10 copies/ml with a gain of +67 CD4+ T-cells/microl; 40% of patients failed. We determined the genotypic score I13V+V32I+L33F/I/V+E35D+ M361/L/V+I47V+F53L+I62V. According to <4, 4-5 and >5 mutations, failure occurred in 11%, 48% and 100% of patients. Failure was associated with CDC stage, baseline CD4+ T-cell count, number of major protease inhibitor resistance mutations, FC and DRV/r score. Pharmacokinetics were not associated with failure, but GIQ was.

CONCLUSION

At W12, 60% of heavily pretreated patients responded on DRV/r-based HAART. Genotypic and phenotypic information constituted the main virological response determinant in patients with optimal drug concentrations.

Diffusion of ertapenem into bone and synovial tissues

OBJECTIVES

The degree of penetration of an antibiotic into the infected site is an important criterion for therapeutic success. Ertapenem is a new carbapenem, exhibiting activity against most Gram-positive and Gram-negative aerobic and anaerobic bacteria commonly recovered from community-acquired infections. However, no studies concerning its diffusion into bone and synovial tissue are available. Our objective was to quantify ertapenem bone and synovial tissue penetration and to compare our data with the MIC(90)s for causative pathogens.

PATIENTS AND METHODS

In an open-label study, 18 patients who were undergoing elective total hip replacement received a single, parenteral, 1 g dose of ertapenem. One serum, one cortical and cancellous bone and one synovial tissue sample was collected per patient a median [interquartile range (IQR)] of 1.6 (1.5-1.7), 12.4 (11.9-13.1) or 23.8 h (22.6-25.2) later and analysed by HPLC.

RESULTS

The median (IQR) serum concentrations of ertapenem were 70.1 (56.1-75.9), 10.0 (9.1-11.2) and 2.6 mg/L (2.3-3.0), respectively, at the different time points. The median (IQR) cancellous bone tissue concentrations were 13.2 (10.2-14.8), 1.9 (1.7-2.1) and 0.6 microg/g (0.4-0.6) at the different time points, corresponding to a median (IQR) tissue/serum penetration ratio of 0.19 (0.18-0.23). The median (IQR) cortical bone tissue concentrations were 8.0 (6.5-9.5), 1.3 (1.2-1.3) and 0.3 microg/g (0.3-0.4) at the different time points, corresponding to a median (IQR) tissue/serum penetration ratio of 0.13 (0.12-0.14). The median (IQR) synovial tissue concentrations were 26.2 microg/g (22.7-28.4), 4.0 mg/L (3.7-4.4) and 1.0 mg/L (0.9-1.2) at the different time points, corresponding to a median (IQR) tissue/serum penetration ratio of 0.41 (0.39-0.42).

CONCLUSIONS

The concentrations after an ertapenem 1 g dose achieved in cancellous and cortical bone tissue and in synovial tissue were greater than the MIC(90)s for most aerobic organisms for 24 h, and for 12 to 24 h for anaerobic bacteria in healthy volunteers undergoing total hip replacement.

Reliability of mini-bronchoalveolar lavage for the measurement of epithelial lining fluid concentrations of tobramycin in critically ill patients

OBJECTIVE

To evaluate the reliability of mini-bronchoalveolar lavage (mini-BAL) for the measurement of tobramycin concentrations in epithelial lining fluid (ELF) in comparison with conventional bronchoscopic bronchoalveolar lavage (BAL).

DESIGN

Prospective, open-label study.

SETTING

An intensive care unit and research ward in a university hospital.

PATIENTS

Twelve critically ill adult patients with ventilator-associated pneumonia (VAP).

INTERVENTIONS

All subjects received intravenous infusions of tobramycin 7-10 mg/kg once daily. After 2 days of therapy, the steady-state serum and ELF concentrations (obtained from BAL and mini-BAL) of tobramycin were determined by means of high-performance liquid chromatography.

MEASUREMENTS AND RESULTS

We observed poor penetration of tobramycin in ELF of approximately approximately 12% with ELF peak concentrations of approximately approximately 3 mg/l with both methods. Good agreement in Bland-Altman analysis (mean +/- SD bias = 0.04 +/- 0.38 mg/l) was observed between the two methods of sampling.

CONCLUSION

Our results suggest that tobramycin 7-10 mg/kg once daily in critically ill patients with VAP might provide insufficient lung concentrations in the case of difficult-to-treat pathogens. Besides, mini-BAL, which is simple, non-invasive and easily repeatable at the bedside, appears to be a reliable method for the measurement of antibiotic concentrations in ELF in comparison with bronchoscopic BAL in critically ill patients with VAP.

Low amounts oftrans18 : 1 fatty acids elevate plasma triacylglycerols but not cholesterol and alter the cellular defence to oxidative stress in mice

Transfatty acids are found mainly in processed foods. It has been shown that when their intake is high, total cholesterol, LDL-cholesterol and triacylglycerols are elevated, while HDL-cholesterol decreases. To evaluate a possible effect of these compounds, even in low amounts, C57Bl/6J mice were fed for 7 weeks a diet containing 13·6 % energy as partially hydrogenated rapeseed oil-enriched diet (Trans diet). The Trans diet contained 3 % energy astrans18 : 1 fatty acid (elaidic acid). Control mice were on an isologous diet containing native rapeseed oil (Rapeseed diet) in whichtransfatty acids were undetectable. Total, free and HDL-cholesterol as well as reverse cholesterol transport did not change. However, plasma triacylglycerol and VLDL levels increased. Hepatic gene expression in the Transv.Rapeseed diet were compared using quantitative RT–PCR. The Trans diet produced a 2–3-fold elevation in mRNA of fatty acid synthase and microsomal transfer protein mRNA, explaining (at least in part) the observed increase in triacylglycerols and VLDL. In addition, mice on the Trans diet developed a deficiency in plasma vitamin E accompanied by a higher concentration of F2-isoprostanes, indicative of increased oxidative stress. The 78 kDa glucose-related protein (GRP78) mRNA expression increased 3–4-fold in liver, suggesting that a response against apoptosis was provoked by lipid peroxidation.

Interpretation of genotype and pharmacokinetics for resistance to fosamprenavir-ritonavir-based regimens in antiretroviral-experienced patients

In this study, named the Zephir study (Telzir-pharmacokinetics), 121 antiretroviral-experienced human immunodeficiency virus (HIV) patients failing on highly active antiretroviral therapy (HAART) were included in a prospective cohort and received a fosamprenavir-ritonavir (700 mg/100 mg twice a day)-based regimen. The impact of baseline HIV type 1 (HIV-1) mutations, pharmacokinetic (PK) parameters, and genotype inhibitory quotient (GIQ) on the virological response at week 12 (W12) was assessed. HIV reverse transcriptase and protease were sequenced at W0. The response at W12 was defined as<2.3 log10 HIV-1 RNA copies/ml or a virus load decrease of>or=1 log10 copies/ml. W4 amprenavir PK were determined by high-performance liquid chromatography. Patients had a median of nine previous treatments over 8 years. Median W0 values were as follows: 295 CD4+/microl, 4.4 log10 HIV-1 RNA copies/ml, and 6 protease- and 5 nucleotide reverse transcription inhibitor-related mutations. Respective values for minimum concentration of drug in serum (Cmin) and area under the concentration-time curve (AUC) from 0 to 24 h were 1,400 ng/ml and 35 mg.h/ml. At W12, 52% of the patients were successes, with a median decrease of -0.7 log10 HIV-1 RNA copies/ml. The Zephir mutation score included 12 IAS protease mutations associated with poorer virological response: L10I/F/R/V, L33F, M36I, M46I/L, I54L/M/T/V, I62V, L63P, A71I/L/V/T, G73A/C/F/T, V82A/F/S/T, I84V, L90M, and polymorphism mutations I13V, L19I, K55R, and L89M. Comparing<4 versus>or=4 mutations, HIV-1 RNA decreases were -2.3 log10 copies/ml versus -0.1 log10 copies/ml (P<10(-4)) with 93% versus 19% successes (P<10(-4)), respectively. This score predicted W12 failure with 94% sensitivity, versus 31% for the ANRS 2005 algorithm. Cmin (<1,600 ng/ml), AUC (<40 mg.h/ml), and GIQ (<300) values were associated with failure (all P values were <10(-4)). The need to test genotype-based algorithms using different patient databases before their implementation in clinical practice is highlighted. Specific mutations, PK and GIQ, provide relevant information for monitoring fosamprenavir-ritonavir-based HAART.

Efficacy and tolerance of high-dose inhaled ipratropium bromide vs. terbutaline in intubated premature human neonates

BACKGROUND

There is insufficient data to reliably assess the benefit of bronchodilators in ventilated premature neonates.

OBJECTIVES

To compare the efficacy/tolerance of inhaled ipratropium bromide (IB) vs. terbutaline (T) and to describe factors associated with their efficacy.

METHODS

A cross-over randomized controlled double-blind trial including intubated neonates with respiratory distress syndrome. Two puffs of IB or T were administered at 0, 20, 40 min. Passive respiratory system resistance (Rrs) and compliance (Crs) were measured at 0, 20, 40, 60 min. A positive response was defined as a >2 individual coefficients of variation decrease in Rrs or increase in Crs.

RESULTS

Twenty-one infants (gestational age (mean +/- SD): 27.3 +/- 1.6 weeks; birth weight: 947 +/- 250 g; postnatal age: 20 +/- 9 days) were included. At 60 min, no treatment effect for Rrs and Crs could be identified (cross-over analysis). Overall data (irrespective of order of administration) showed that after 6 puffs, the decrease in Rrs was greater in the IB vs. T group (-17.0 +/- 22.2% vs. -11.3 +/- 26.7%, respectively (NS)). Thirty-eight percent of infants responded to IB vs. 43% to T. However, in 19% of patients, decreased Crs was observed after 6 puffs of T. No marker of a positive or paradoxical response could be identified. Treatment was well-tolerated.

CONCLUSION

High doses of bronchodilators are required in ventilated neonates, but the positive response rate was <50%. Their long-term benefit remains to be proven.

Pharmacokinetics and lung concentrations of ertapenem in patients with ventilator-associated pneumonia

OBJECTIVE

We conducted a prospective, open-label study to determine the steady-state serum and epithelial lining fluid (ELF) concentrations of unbound ertapenem administered once daily to critically ill patients with early-onset ventilator-associated pneumonia (VAP).

DESIGN AND SETTING

Prospective, open-label study in an intensive care unit and research ward in a university hospital.

PATIENTS

Fifteen patients with VAP received 1-h intravenous infusions of 1 g ertapenem once daily.

INTERVENTIONS

After 2 days of therapy the steady-state serum and ELF concentrations of free ertapenem were determined by high-performance liquid chromatography.

MEASUREMENTS AND RESULTS

The median (interquartile range) free ertapenem peak (C(max)), intermediate (C(12)), and trough (C(min)) concentrations (mg/l) 1, 12, and 24 h after the end of infusion were 30.3 (27.1-37.8), 4.8 (3.9-6.4), and 0.8 (0.5-1.2) in serum and 9.4 (8.0-10.7), 2.0 (1.1-2.5), and 0.3 (0.2-0.4) in ELF, respectively, showing a median free ertapenem percentage penetration in ELF of approx. 30%. The median (interquartile range) serum area under concentration-time curve of free ertapenem during the observational period was 226.7 mg h(-1) l(-1) (202.2-263.9).

CONCLUSION

Our study shows satisfactory results, with unbound ertapenem concentrations both in serum and ELF exceeding the MIC(90) values of most of the causative pathogens encountered in early-onset VAP during 50-100% time. This suggests that 1 g intravenous ertapenem administered once daily should be effective during the treatment of early-onset VAP in critically ill patients with no known risk factors for multidrug-resistant pathogens.

Intracellular and plasma efavirenz concentrations in HIV-infected patients switching from successful protease inhibitor-based highly active antiretroviral therapy (HAART) to efavirenz-based HAART (SUSTIPHAR Study)

OBJECTIVES

To assess intracellular and plasma efavirenz concentrations in HIV-infected patients who switched to efavirenz-based highly active antiretroviral therapy (HAART) from successful protease inhibitor-based HAART.

PATIENTS AND METHODS

A total of 49 patients were included in this observational cohort study. At inclusion, all patients had plasma HIV-RNA levels<50 copies/mL and switched to efavirenz combined with two nucleoside reverse transcriptase inhibitors. Intracellular and plasma concentrations were measured 12 h post-dose, 1 month (M1) and 6 months (M6) after starting efavirenz. Virological success (VS) was defined as plasma HIV-RNA level<50 copies/mL within the first 12 months and remaining undetectable at the end of the follow-up.

RESULTS

VS was documented in 48 patients for at least 12 months (range 12-78 months). High inter-patient variabilities of intracellular and plasma efavirenz concentrations were observed (coefficients of variation>40%). At M1 and M6, respectively, median [Q1; Q3] intracellular efavirenz concentrations were 5300 [2830; 11 530] and 6790 [3870; 8790] ng/mL, median plasma efavirenz concentrations were 2050 [1600; 3100] and 2100 [1410; 2500] ng/mL. No correlation was found between intracellular and plasma concentrations. Plasma efavirenz levels exceeded the proposed threshold of 1000 ng/mL in 96% of patients from M1.

CONCLUSIONS

For moderately pre-treated HIV-infected patients with few mutations who switched to efavirenz from previous successful HAART, the proposed plasma efficacy-threshold was reached without any dosage adaptation. VS was maintained beyond 12 months, despite high inter-patient and intra-patient variabilities of intracellular and plasma efavirenz concentrations.

Virological Responses to Atazanavir–Ritonavir-Based Regimens: Resistance-Substitutions Score and Pharmacokinetic Parameters (Reyaphar Study)

Objective

To assess the impact of baseline HIV-1 substitutions, individual pharmacokinetic (PK) parameters (Cmin, Cmax, area under the curve [AUC0→24 h]) and genotype-inhibitory quotient (GIQ) on virological responses (VR) to atazanavir-ritonavir (300 mg/100 mg)-based highly active antiretroviral therapy (HAART) in 71 antiretroviral-experienced, atazanavir-naive patients in virological failure (VF) on HAART.

Methodology

VR was defined as HIV RNA <1.7 log10 copies/ml at week 12 (W12). A clinically relevant genotype-substitutions score for atazanavir-ritonavir was developed and validated (Reyaphar substitutions score). Previously published substitutions scores were also tested.

Results

Patients had a median (Q1; Q3) of 6 (3; 8) previous treatment lines during 9 (7; 11) years. Baseline (W0) values were as follows: 262 (187; 435) CD4+/μl, 3.9 (2.6; 4.9) log10 HIV-1 RNA copies/ml, 4 (2; 6) protease substitutions and 3 (1; 4) NRTI-related substitutions. Respective steady-state Cmin, Cmax and AUC0→24h were 300 (200; 700) ng/ml, 620 (430; 750) ng/ml and 78,000 (61,000; 94,000) ng.h/ml. At W12, 49% of the patients had VR with a median decrease of -1.2 (-0.5; -2.3) log10 HIV-1 RNA copies/ml. The Reyaphar score included 12 baseline protease substitutions from the International AIDS Society USA list that were associated with poorer VR: L10I/F/R/V, K20I/M/R, L24I, M46I/L, I54L/M/T/V, L63P, A71I/L/V/T, G73A/C/F/T, V77I, V82A/F/S/T, I84V, L90M and the polymorphism substitution Q58E. Comparing <5 versus ≥5 Reyaphar substitutions, the W12-W0 HIV-1 RNA decrease was -1.4 (-0.7; -2.3) versus -0.5 (-1.2; +0.5) log10 copies/ml ( P=0.009) with VR in 63% versus 11% ( P<10–4), respectively. This score predicted VF at W12 with 46% sensitivity, compared to 33% and 28% for the ANRS 2004 and 2005 scores. PK parameters alone were not associated with VR, but GIQ was associated with virological outcome ( P=0.04). I50L, known to be correlated with atazanavir-specific resistance, emerged in 2 (8%) of the 24 failing patients with paired genotypes at W0 and VF.

Conclusions

These findings highlight the need to cross-validate genotype-based algorithms to interpret substitution impact on virological outcome using different patient databases before their implementation in routine clinical practice.

Steady-state trough serum and epithelial lining fluid concentrations of teicoplanin 12 mg/kg per day in patients with ventilator-associated pneumonia

OBJECTIVE

To determine the steady-state trough serum and epithelial lining fluid (ELF) concentrations of teicoplanin 12 mg/kg per day in critically ill patients with ventilator associated pneumonia.

DESIGN AND SETTING

Prospective, pharmacokinetic study in the surgical intensive care unit in a university hospital.

PATIENTS

Thirteen adult patients with nosocomial bacterial pneumonia on mechanical ventilation were enrolled.

INTERVENTIONS

All subjects received a 30-min intravenous infusion of 12 mg/kg teicoplanin every 12 h for 2 consecutive days followed by 12 mg/kg once daily. Teicoplanin concentrations in serum and ELF were determined simultaneously 4-6 days after antibiotic administration started.

MEASUREMENTS AND RESULTS

The median total and free concentrations of teicoplanin in serum at trough were 15.9 microg/ml (range 8.8-29.9) and 3.7 (2.0-5.4), respectively. The concentration in ELF was 4.9 (2.0-11.8).

CONCLUSIONS

In critically ill patients with ventilator-associated pneumonia the administration of high teicoplanin doses is required to reach sufficient trough antibiotic concentrations in lung tissues at steady state. At that time trough-free concentrations of teicoplanin in serum and ELF are comparable.

Determination of free ertapenem in plasma and bronchoalveolar lavage by high-performance liquid chromatography with ultraviolet detection

A sensitive assay for the determination of unbound ertapenem in human plasma and bronchoalveolar lavage (BAL) was developed using ultrafiltration of plasma and BAL samples. A rapid HPLC method was used with ultraviolet detection set at a wavelength of 305 nm and a separation on a Prontosil AQ C18 column, with imipenem used as internal standard. This assay was linear over the concentration range of 0.5-100 microg/mL and 0.25-50 microg/mL in plasma and BAL, respectively. Limits of detection and quantitation were respectively 0.05 and 0.25 microg/mL. Validation data for accuracy and precision were CV<2.48 and 8.25%, accuracy in the range 98.1-104.2% and 102.2-108.4%, respectively, for intra and inter-day.

Virological responses to atazanavir-ritonavir-based regimens: resistance-substitutions score and pharmacokinetic parameters (Reyaphar study)

OBJECTIVE

To assess the impact of baseline HIV-1 substitutions, individual pharmacokinetic (PK) parameters (Cmin, Cmax, area under the curve [AUC0-->24 h]) and genotype-inhibitory quotient (GIQ) on virological responses (VR) to atazanavir-ritonavir (300 mg/100 mg)-based highly active antiretroviral therapy (HAART) in 71 antiretroviral-experienced, atazanavir-naive patients in virological failure (VF) on HAART.

METHODOLOGY

VR was defined as HIV RNA <1.7 log10 copies/ml at week 12 (W12). A clinically relevant genotype-substitutions score for atazanavir-ritonavir was developed and validated (Reyaphar substitutions score). Previously published substitutions scores were also tested.

RESULTS

Patients had a median (Q1; O3) of 6 (3; 8) previous treatment lines during 9 (7; 11) years. Baseline (WO) values were as follows: 262 (187; 435) CD4+/microl, 3.9 (2.6; 4.9) log10 HIV-1 RNA copies/ml, 4 (2; 6) protease substitutions and 3 (1; 4) NRTI-related substitutions. Respective steady-state Cmin, Cmax and AUC0-->24 h were 300 (200; 700) ng/ml, 620 (430; 750) ng/ml and 78,000 (61,000; 94,000) ng.h/ml. At W12, 49% of the patients had VR with a median decrease of -1.2 (-0.5; -2.3) log10 HIV-1 RNA copies/ml. The Reyaphar score included 12 baseline protease substitutions from the International AIDS Society USA list that were associated with poorer VR: L10I/F/R/V, K20I/M/R, L241, M461/L, 154L/M/T/V, L63P, A71I/L/V/T, G73A/C/F/T, V771, V82A/F/S/T, 184V, L90M and the polymorphism substitution Q58E. Comparing <5 versus > or =5 Reyaphar substitutions, the W12-W0 HIV-1 RNA decrease was - 1.4 (-0.7; -2.3) versus -0.5 (-1.2; +0.5) log10 copies/ml (P=0.009) with VR in 63% versus 110% (P<10(-4)), respectively. This score predicted VF at W12 with 46% sensitivity, compared to 33% and 28% for the ANRS 2004 and 2005 scores. PK parameters alone were not associated with VR, but GIQ was associated with virological outcome (P=0.04). 150L, known to be correlated with atazanavir-specific resistance, emerged in 2 (8%) of the 24 failing patients with paired genotypes at WO and VF.

CONCLUSIONS

These findings highlight the need to cross-validate genotype-based algorithms to interpret substitution impact on virological outcome using different patient databases before their implementation in routine clinical practice.

Pharmacokinetics and intrapulmonary concentrations of linezolid administered to critically ill patients with ventilator-associated pneumonia

OBJECTIVE

To determine the steady-state plasma pharmacokinetic variables and epithelial lining fluid concentrations of linezolid administered to critically ill patients with ventilator-associated pneumonia.

DESIGN

Prospective, open-label study.

SETTING

An intensive care unit and research ward in a university hospital.

PATIENTS

Sixteen critically ill adult patients with ventilator-associated pneumonia.

INTERVENTIONS

All subjects received 1-hr intravenous infusions of linezolid 600 mg twice daily. After 2 days of therapy, the steady-state plasma pharmacokinetic variables and epithelial lining fluid concentrations of linezolid were determined by high-performance liquid chromatography.

MEASUREMENTS AND MAIN RESULTS

The mean +/- sd linezolid peak and trough concentrations were 17.7 +/- 4.0 mg/L and 2.4 +/- 1.2 mg/L in plasma and 14.4 +/- 5.6 mg/L and 2.6 +/- 1.7 mg/L in epithelial lining fluid, respectively, showing a mean linezolid percentage penetration in epithelial lining fluid of approximately 100%. The mean +/- sd area under concentration-time curve during the observational period (AUC0-12) was 77.3 +/- 23.7 mg x hr/L, corresponding to a mean AUC0-24 of 154.6 mg x hr/L.

CONCLUSIONS

Our study shows satisfactory results, with linezolid concentrations exceeding the susceptibility breakpoint for Gram-positive bacteria in both plasma and epithelial lining fluid. This suggests that a dosage of 600 mg administered intravenously twice daily to critically ill patients with Gram-positive ventilator-associated pneumonia would achieve success against organisms with minimum inhibitory concentrations as high as 2-4 mg/L in both plasma and epithelial lining fluid.

Pharmacokinetics and intrapulmonary diffusion of levofloxacin in critically ill patients with severe community-acquired pneumonia

OBJECTIVE

To determine the steady-state plasma and epithelial lining fluid concentrations of intravenous levofloxacin, 500 mg, administered once or twice daily in critically ill patients with severe community-acquired pneumonia.

DESIGN

Prospective, open-label study.

SETTING

An intensive care unit and a clinical pharmacokinetic laboratory in two university hospitals.

PATIENTS

Twenty-four adult patients with severe community-acquired pneumonia and receiving mechanical ventilation were enrolled.

INTERVENTIONS

All subjects received 1-hr intravenous infusions of 500 mg levofloxacin once or twice daily. The plasma and epithelial lining fluid levofloxacin concentrations were determined at steady-state after 2 days of therapy with high-performance liquid chromatography.

MEASUREMENTS AND MAIN RESULTS

The median (interquartile range [IQR]) plasma and epithelial lining fluid peak levofloxacin concentrations were 12.6 (IQR, 12.0-14.1) and 11.9 (IQR, 8.7-13.7) mg/L, respectively, in the once-daily group and 19.7 (IQR, 19.0-22.0) and 17.8 (IQR, 16.2-23.5) mg/L in the twice-daily group, showing a pulmonary percentage penetration of >100% in both groups. The median (IQR) total body exposures were 151 (IQR, 137-174) and 416 (IQR, 406-472) mg.hr/L, respectively, in the once-daily and twice-daily groups.

CONCLUSIONS

Our results suggest that in critically ill patients who are receiving mechanical ventilation and have severe community-acquired pneumonia and creatinine clearance of >40 mL/min, the administration of 500 mg of intravenous levofloxacin once and twice daily allows for the exceeding of pharmacodynamic thresholds predictive of outcome (i.e., peak concentration to minimum inhibitory concentration ratio of >10 or area under concentration-time curve to minimal inhibitory concentration ratio of >125 hrs) both in serum and epithelial lining fluid for pathogens with minimum inhibitory concentration values of < or =1 mg/L and >1 mg/L, respectively.