Therapeutic drug monitoring and virological response at week 48 in a cohort of HIV-1-infected patients switching to dolutegravir/rilpivirine dual maintenance therapy (ANRS-MIE-BIRIDER study).

AIMS: Dolutegravir (DTG) and rilpivirine (RPV) dual therapy is now recommended as a switch option in virologically suppressed HIV patients. Literature suggests that virological failure with dual therapy could possibly relate to subtherapeutic drug concentrations. In this study, we aimed at describing the DTG and RPV trough plasma concentrations (Cmin) and plasma HIV-1 RNA viral load (VL) during maintenance dual therapy. METHODS: We performed a retrospective analysis of DTG and RPV therapeutic drug monitoring in people living with HIV/AIDS (PLWHA) with dual therapy in 9 French centres. DTG and RPV trough plasma concentrations were estimated using a Bayesian approach to predict Cmin. The relationship between the pharmacokinetics of DTG and RPV and VL > 50 copies (cp)/mL was explored using joint nonlinear mixed models. The frequency of subtherapeutic threshold (DTG Cmin below 640 ng/mL and RPV Cmin below 50 ng/mL) were compared between PLWHA presenting VL > 50 cp/mL or not during the study. RESULTS: At baseline, 209 PLWHA were enrolled in the study. At week 48, 19 people living with HIV/AIDS (9.1%) discontinued their treatment and 15 PLWHA (7.1%) exhibited VL > 50 cp/mL. Six PLWHA out of 15 (40.0%) with VL > 50 cp/mL during the follow-up had at least 1 Cmin below the respective thresholds while only 26/194 patients (13.4%) without virological replication had at least 1 concentration below the threshold (P = .015). CONCLUSION: A majority of PLWHA receiving DTG/RPV maintenance dual therapy demonstrated VL < 50 cp/mL but virological replication was more frequent in people living with HIV/AIDS with subtherapeutic Cmin.

A HPLC-DAD method to facilitate large-scale therapeutic drug monitoring of dalbavancin.

Dalbavancin, a long-acting lipoglycopeptide antibiotic targeting susceptible Gram-positive bacteria, is WHO critically important antibiotic, increasingly used in critical situations such as osteoarticular infections. To ensure its effectiveness and its safety, the therapeutic drug monitoring (TDM) of dalbavancin is strongly recommended. In the absence of an available minimum inhibitory concentration (MIC), the European Committee on Antimicrobial Susceptibility Testing (EUCAST) recommends a breakpoint of 0.125 mg/L for Staphylococcus aureus, corresponding to a trough target concentration of 25 mg/L. Nowadays, the TDM is usually performed using a high-performance liquid chromatography (HPLC) method coupled with a tandem mass spectrometry. However, this expensive and specialized equipment and reagents may be difficult to acquire for non-specialized laboratories. The use of HPLC coupled with diode array detector (DAD) facilitates TDM with a lower cost, while preserving the reliability of the results. Our aim was to provide a sensitive and specific method, relying on HPLC-DAD for extending the TDM of dalbavancin beyond non-specialized labs, therefore maximizing its efficiency and Benefit/risk ratio. Our method complied with the European Medicines Agency guidelines of bioanalytical validation. Irrespective of the concentrations of dalbavancin, the coefficient of variation < 10% confirmed the reliability of this analytical method, with a calibration curve ranging from 5 to 100 mg/L. No interferences nor carryover was observed. Our HPLC-DAD method, combined with a simple extraction, provides a widely usable, inexpensive and easy-to-implement new asset for the TDM of Dalbavancin.

Raltegravir Inclusion Decreases CD4 T-Cells Intra-Cellular Viral Load and Increases CD4 and CD28 Positive T-Cells in Selected HIV Patients.

Raltegravir (RLT) prevents the integration of HIV DNA in the nucleus, but published studies remain controversial, suggesting that it does not decrease proviral DNA. However, there are only a few studies focused on virus-targeted cells. We aimed our study on the impact of RLT inclusion on total intra-cellular viral DNA (TID) in cellular subsets and immune effects in patients with newly acquired undetectable plasmatic viral load (UVL). Six patients having UVL using an antiretroviral combination for 6 months and CD4 T-cells > 350/mL and <500/mL were selected to receive RLT for 3 months from M0 to M3. Patients had 7 sequential viro-immunological determinations from M-1 to M5. Immune phenotypes were determined by flow cytometry and TID quantification was performed using PCR assay on purified cells. TID (median values) at the initiation of RLT in CD4 T-cells was 117 copies/millions of cells, decreased to 27.5 on M3, and remained thereafter permanently under the cut-off (<10 copies/millions of cells) in 4 out of 6 patients. This was associated with an increase of CD4 and CD4 + CD28+ T-cells and a decrease of HLA-DR expression and apoptosis of CD4 T-cells. RLT inclusion led to decreases in the viral load along with positive immune reconstitution, mainly for CD4 T-cells in HIV patients.

Incidence of diabetes in HIV-infected patients treated with first-line integrase strand transfer inhibitors: a French multicentre retrospective study.

BACKGROUND: Integrase strand transfer inhibitors (INSTIs) are increasingly used in patients living with HIV due to their safety, effectiveness and high genetic barrier. However, an association with weight gain has recently been suggested and several cases of diabetes mellitus have been reported with raltegravir and dolutegravir. The long-time metabolic impact of these recent molecules remains unclear. OBJECTIVES: To assess if an INSTI as a third agent is statistically associated with new-onset diabetes mellitus compared with an NNRTI or a PI. PATIENTS AND METHODS: Patients undergoing first-line combined ART (cART) without diabetes at baseline were retrospectively included from the Dat'AIDS French cohort study (ClinicalTrials.gov NCT02898987). Incident diabetes mellitus was defined as a notification of new diabetes in the medical history, a glycated haemoglobin (HbA1c) level superior to 7.5% or the start of a diabetes therapy following the initiation of ART. RESULTS: From 2009 to 2017, 19 462 patients were included, among which 265 cases of diabetes mellitus occurred. Multivariate and survival analyses did not highlight an increase in new-onset diabetes in patients undergoing cART with an INSTI as a third agent compared with an NNRTI or a PI. BMI >30 kg/m2, age >37 years old (in survival analysis), black race or Hispanic ethnicity, arterial hypertension and AIDS were associated with a higher proportion of incident diabetes. CONCLUSIONS: INSTIs were not statistically associated with new-onset diabetes. However, clinicians should remain aware of this possible metabolic comorbidity, particularly in patients with a high BMI and older patients.

Concerns about pharmacokinetic (PK) and pharmacokinetic-pharmacodynamic (PK-PD) studies in the new therapeutic area of COVID-19 infection.

In the context of the COVID-19 pandemic, several drugs have been repurposed as potential candidates for the treatment of COVID-19 infection. While preliminary choices were essentially based on in vitro potency, clinical translation into effective therapies may be challenging due to unfavorable in vivo pharmacokinetic properties at the doses chosen for this new indication of COVID-19 infection. However, available pharmacokinetic and pharmacokinetic-pharmacodynamic studies suffer from severe limitations leading to unreliable conclusions, especially in term of dosing optimization. In this paper we propose to highlight these limitations and to identify some of the major requirements that need to be addressed in designing PK and PK-PD studies in this era of COVID. A special attention should be paid to pre-analytical and analytical requirements and to the proper collection of covariates affecting dose-exposure relationships (co-medications, use of specific organ support techniques and other clinical and para-clinical data). We also promote the development of population PK and PK-PD models specifically dedicated to COVID-19 patients since those previously developed for other diseases (SEL, malaria, HIV) and clinical situations (steady-state, non-ICU patients) are not representative of severe patients. Therefore, implementation of well-designed PK and PD studies targeted to COVID-19 patients is urgently needed. For that purpose we call for multi-institutional collaborative work and involvement of clinical pharmacologists in multidisciplinary research consortia.

Cefoxitin-based antibiotic therapy for extended-spectrum ß-lactamase-producing Enterobacteriaceae prostatitis: a prospective pilot study.

The emergence of extended-spectrum ß-lactamase-producing Enterobacteriaceae (ESBL-E) infections requires re-assessment of therapeutic choices. Here we report the efficacy of cefoxitin-based antibiotic therapy for ESBL-E prostatitis. A prospective study including patients with ESBL-E prostatitis resistant to trimethoprim/sulfamethoxazole and fluoroquinolones from January 2014 to March 2016 was conducted. Cefoxitin was administered by continuous infusion for 3 weeks in the case of acute bacterial prostatitis or 6 weeks in the case of chronic bacterial prostatitis (CBP), with intravenous fosfomycin for the first 5 days. Urological investigations were performed to diagnose underlying urinary tract pathology. Clinical and microbiological efficacy were evaluated 3 months (M3) and 6 months (M6) after the end of therapy. A total of 23 patients were included in the study. The median patient age was 74 years (range 48-88 years). Of the 23 infections, 14 (61%) were CBP and 12 (52%) were healthcare-associated infections. The bacteria involved were Escherichia coli in 11 cases, Klebsiella pneumoniae in 10 cases and Klebsiella oxytoca in 2 cases. Clinical cure was observed in 19/23 patients (83%) at M3 and in 17/22 patients (77%) at M6. Urocultures were sterile in 13/23 patients (57%) at M3 and in 9/19 patients (47%) and M6. Urinary colonisation was observed in 6/19 patients (32%) with clinical cure at M3 and 5/14 patients (36%) with clinical cure at M6. No resistance to cefoxitin was detected. Surgical treatment was required for 7/23 patients (30%). In conclusion, cefoxitin-based antibiotic therapy is suitable for difficult-to-treat ESBL-E infections such as prostatitis.

ITPA deficiency and ribavirin level are still predictive of anaemia in HCV-HIV-coinfected patients receiving ribavirin combined with a first-generation DAA (ANRS HC27 study).

BACKGROUND: We aimed to determine the impact of inosine triphosphatase (ITPA) deficiency on ribavirin (RBV)-induced anaemia in HIV-HCV-coinfected patients receiving a triple therapy including the haematotoxic direct-acting antiviral agent boceprevir (BOC). METHODS: Patients of the ANRS HC27 BocepreVIH study were genotyped for two ITPA single nucleotide polymorphisms involved in ITPA deficiency. RBV trough concentration (Ctrough) was determined at week (W)4 and W8. Impact of ITPA deficiency on anaemia, RBV Ctrough, response and haematotoxicity (grade 3/4 anaemia, erythropoietin [EPO] use, RBV dose reduction or transfusion between day [D]0 and W8) was evaluated. Impact of RBV Ctrough on anaemia was also studied. RESULTS: Among the 63 genotyped patients, 33% had a predicted ITPA deficiency. ITPA deficiency was associated with a lower haemoglobin (Hb) decline both at W4 (-1.0 g/dl versus -2.1 g/dl; P=0.02) and W8 (-2.7 g/dl versus -4.1 g/dl; P=0.05). None of the patients with ITPA deficiency received EPO between D0-W8 versus 26% of patients without ITPA deficiency (P=0.01). RBV Ctrough was associated with Hb decrease both at W4 and W8 and an RBV Ctrough cutoff value of 2 µg/ml was significantly associated with a W4 Hb decline >2 g/dl. Haematotoxicity was significantly associated with a lower W4 Hb level (P=0.017), absence of ITPA deficiency (P=0.018) and higher RBV Ctrough (P=0.012). ITPA deficiency, W4 RBV Ctrough and gender were independent predictors of anaemia at W4. ITPA deficiency was not associated with virological response. CONCLUSIONS: ITPA deficiency and RBV Ctrough are still predictive of RBV-induced anaemia in HIV-HCV-coinfected patients treated with RBV combined with a first-generation direct antiviral agent.

Switch to Ritonavir-Boosted versus Unboosted Atazanavir plus Raltegravir Dual-Drug Therapy Leads to Similar Efficacy and Safety Outcomes in Clinical Practice.

OBJECTIVES: To assess immunovirological response, safety and pharmacokinetic of NRTI-sparing regimen dual therapy of atazanavir (ATV) and raltegravir (RAL) in maintenance strategy. METHODS: A retrospective analysis was conducted on a cohort of HIV-infected adults followed in French centers (Dat'AIDS cohort), comparing the proportions of virological and therapeutic failures between ATV + RAL and ATV/ritonavir + RAL dual therapy regimens. RESULTS: 283 patients were assessed: 185 switched for ATV + RAL and 98 for ATV/ritonavir + RAL dual therapy. Virological failure rate at week 96 was 13.8% (95% CI, 9.8-17.8), without difference between the two groups (Log-rank Test, p = 0.87). The cumulative percentages of patients remaining free of therapeutic failure at week 24, 48 and 96 of dual therapy were 74.9% (95% CI, 69.9-80.0), 65.4% (95% CI, 59.8-70.9) and 53.4% (95% CI, 47.5-59.2), respectively. Four out of 39 confirmed virological failures developed RAL resistance. By multivariate analysis, virological failure was associated with high HIV-1 RNA zenith (p = 0.02), low CD4+ T-cell count at baseline (p<0.001) and short duration on antiretroviral therapy (p<0.001). Before week 96, dual therapy was discontinued in 44 patients (16%) because of various adverse events, with no difference between the two groups. Minimal plasma levels were targeted in 84% and 87% of patients for ATV and RAL, respectively, and both were significantly higher in ritonavir-boosted regimen. CONCLUSIONS: Emerging RAL-resistance and discontinuations for adverse events resulted in moderate efficacy rates of ATV and RAL dual therapy in heavily pretreated patients.

Long-term efficacy and toxicity of abacavir/lamivudine/nevirapine compared to the most prescribed ARV regimens before 2013 in a French Nationwide Cohort Study.

Data on the long-term efficacy and safety of abacavir/lamivudine (ABC/3TC) and nevirapine (NVP) are scarce. This combination has the advantage of simplifying treatment and improving long-term tolerance. The aim of this study was to compare the rate of any discontinuation of antiretroviral (ARV) regimen because of virologic failure (VF), and/or adverse drug reaction (ADR) among patients receiving stable ARV regimens for at least 6 months.ABC/3TC/NVP was compared to ABC/3TC with either ritonavir-boosted darunavir (DRV/r) or ritonavir-boosted atazanavir (ATV/r), unboosted ATV, or tenofovir/emtricitabine (TDF/FTC) with either one of the following: ATV/r, unboosted ATV, DRV/r, efavirenz (EFV), or NVP, in the French prospective multicenter Dat'AIDS cohort.The study enrolled 16,511 patients treated with following ARV regimens: ABC/3TC/NVP (n = 1089), TDF/FTC/NVP (n = 1542), ABC/3TC/DRV/r (n = 1065), ABC/3TC/ATV/r (n = 1847), ABC/3TC/ATV (n = 563), TDF/FTC/ATV/r (n = 3519), TDF/FTC/DRV/r (n = 2767), TDF/FTC/ATV (n = 419), and TDF/FTC/EFV (n = 3700). Mean follow-up was 36 ±â€Š24 months. Patients treated with ABC/3TC/NVP received this regimen as a switch regimen in 97% of cases. By multivariable analysis, the risk of treatment discontinuation due to VF was similar between ABC/3TC/NVP and other ARV regimens, except for TDF/FTC/ATV and ABC/3TC/ATV, which were associated with a higher risk of treatment interruption due to VF (hazard ratio [HR] 1.99; 95% confidence interval [CI] 1.29-3.06 and HR 2.19; 95% CI 1.51-3.18, respectively). Treatment discontinuation due to ADR was lowest with the ABC/3TC/NVP regimen. Other ARV regimens were associated with a 1.80- to 3.19-fold increase in the risk of treatment discontinuation due to ADR (P < 0.0001 for all comparisons).ABC/3TC/NVP as a simplification regimen is a long-term effective regimen with lower discontinuation due to long-term toxicity compared with other standard ARV regimens.

Estimated glomerular filtration rate but not solute carrier polymorphisms influences anemia in HIV-hepatitis C virus coinfected patients treated with boceprevir or telaprevir-based therapy.

OBJECTIVES: Ribavirin (RBV) induced anemia may be influenced by host genetic factors affecting RBV transport solute carrier (SLC) or metabolism inosine triphosphatase (ITPA), as already reported. We investigated the influence of single nucleotide polymorphisms (SNPs) on SLC genes on anemia, RBV trough concentration (Ctrough) and response in HIV-hepatitis C virus coinfected patients receiving triple therapy with boceprevir or telaprevir. METHODS: Patients from the ANRS HC26/HC27 studies were genotyped for SLC28A3 SNPs (rs10868138 and rs56350726) and SL29A1 SNPs (rs760370). Hemoglobin (Hb) decline was collected at baseline day 0 (D0), week 4 (W4) and week 8 (W8), and RBV Ctrough was measured at W4 and W8 by HPLC. A multivariate analysis including SLC SNPs, estimated glomerular filtration rate (eGFR), ITPA deficiency and RBV Ctrough was performed to determine predictive factors of anemia and response. RESULTS: SLC genotyping was performed in 130 patients. Neither SLC28A3 nor SLC29A1 SNPs were associated with Hb decline both at W4 and W8. No association was found between SLC polymorphisms and RBV Ctrough. Independent predictive factors of Hb decline at W4 were D0 Hb, ITPA deficiency and W4 RBV Ctrough in the multivariate analysis (P < 0.05). Only D0 Hb, W4 RBV Ctrough and eGFRD0-W8 were predictive of anemia at W8 (P < 0.05). Response was not influenced by SLC SNPs. CONCLUSION: eGFR, but not SLC polymorphisms, influences anemia in HIV-hepatitis C virus coinfected patients receiving boceprevir-based or telaprevir-based therapy. RBV is still a cornerstone of hepatitis C treatment, thus renal function and RBV Ctrough should be monitored in patients receiving RBV regimen combined with first-generation direct-acting antiviral agent.

Addition of boceprevir to PEG-interferon/ribavirin in HIV-HCV-Genotype-1-coinfected, treatment-experienced patients: efficacy, safety, and pharmacokinetics data from the ANRS HC27 study.

BACKGROUND: Scarce data exist on the efficacy and safety of the PEGylated-interferon/ribavirin/boceprevir regimen in HIV/HCV-coinfected patients who failed to respond to PEGylated-interferon/ribavirin treatment. OBJECTIVES: To evaluate the efficacy and safety of this drug regimen and the impact of the addition of boceprevir(BOC) on atazanavir (ATV) or raltegravir (RAL) pharmacokinetic parameters in a subgroup of patients. METHODS: In this single-arm phase 2 trial, HIV-1/HCV-genotype-1-coinfected patients received PEGylated-interferonα2b (1.5 µg/kg/week)+ ribavirin (800-1400 mg/day) alone until W4 and with BOC(800 mgTID) until W48. Based on virologic response at W8, the three drugs were stopped or PEGylated-interferon/ribavirin was continued alone until W72. The primary endpoint was SVR at W24 off-therapy (SVR24). RESULTS: 64 patients were included. SVR24 was achieved in 53% of patients (CI90%: 43-63%) and in 90% of previous relapsers. In univariate analysis, SVR24 was associated with response to previous HCV treatment, HCV-1b subtype, HCV-RNA decline, ribavirin-Ctrough at W4, and HCV-RNA at W8 but not to fibrosis score, IL28B genotype, or boceprevir-Ctrough at W8. In multivariate analysis, SVR24 remained associated with response to previous HCV treatment [non-responders versus null responders: OR=5.0(1.3-20.0); relapsers vs. null responders: OR=28.8(4.9-169.5)]. HCV treatment was discontinued for adverse events in 17% of patients. A 51% decrease in ATV/r-AUC0-8 h (p<0.01) and a 57% increase in RAL-AUC0-8 h (p<0.01) were observed, although atazanavir/r or raltegravir did not affect BOC-AUC0-8 h significantly. The ATV mean Cthrough fell from 763.8 ng/mL (CI 95%: 230.3-1297.3) without BOC to 507.7 ng/mL (CI 95%: 164-851.4) with BOC. CONCLUSIONS: Boceprevir-based regimen demonstrated a high SVR24 rate in treatment-experienced HIV-HCV genotype-1-coinfected relapsers.

Successful antiretroviral therapy by using unusual antiretroviral combinations in heavily pre-treated patients: two case reports.

In the context of HIV-infected patients with several past antiretroviral therapies and multiple failures, it is possible to be faced with viruses resistant to all drug classes. We report on two HIV-1 infected patients in which the historical genotype showed mutations against all the major drug classes and in which viral suppression has been obtained by non-conventional antiretroviral therapy regimens, including the combination of darunavir at high dosage (800 mg bid), dolutegravir (50 mg bid) and a third agent, i.e. enfuvirtide in the first case and etravirine in the second one.

Ribavirin and abacavir drug interaction in HIV-HCV coinfected patients: fact or fiction?

OBJECTIVE(S): To examine the impact of ribavirin and abacavir coadministration on hepatitis C virus (HCV) virological response and trough ribavirin plasma concentration (Cmin) in HIV-HCV coinfected patients. DESIGN: Pharmacokinetic substudy on patients from the ANRS CO-13 HEPAVIH cohort. METHODS: Patients receiving ribavirin-pegylated interferon for whom a ribavirin steady state Cmin was prospectively determined were included. Rapid virological response (RVR), early virological response (EVR) and sustained virological response (SVR) as well as HCV-RNA decline were evaluated. RESULTS: Overall, 124 HIV-HCV coinfected patients (95% on antiretroviral therapy) were enrolled. Of these patients, 22% received abacavir. The overall median (interquartile range) ribavirin Cmin was 1.6 mg/l (1.2-2.2) with no statistical difference between abacavir users and nonusers [1.5 mg/l (0.99-2.1) and 1.7 (1.2-2.3), P = 0.15]. RVR and EVR were 52 and 72%, respectively. There was no difference observed in the proportion of abacavir users vs. nonusers achieving RVR (respectively 59 vs. 50%, P = 0.40) or EVR (72 vs. 73%, P = 0.94), or in the HCV-RNA decline at week 4 [-2.24 log(10) IU/ml, (-3.58; -0.81) and -1.27 (-2.8; -0.47) P = 0.28] or at week 12 [-1.76 log(10) IU/ml (-3.67; -0.35) and -1.85 (-3.13; -1.13) (P = 0.58)]. The SVR rate was 45% for abacavir users and 24% for abacavir nonusers, but the difference was not statistically significant (P = 0.059). CONCLUSION: In our study, there was no evidence that abacavir affected HCV treatment outcomes and the ribavirin Cmin was similar in abacavir users and nonusers, confirming the absence of pharmacokinetic interaction between abacavir and ribavirin. An abacavir-containing regimen is, therefore, a well tolerated treatment alternative for coinfected patients starting HCV treatment.

Continuous versus intermittent infusions of ceftazidime for treating exacerbation of cystic fibrosis.

The present multicenter, randomized crossover study compared the safety and efficacy of continuous infusion with those of short infusions of ceftazidime in patients with cystic fibrosis. Patients with chronic Pseudomonas aeruginosa colonization received two successive courses of intravenous tobramycin and ceftazidime (200 mg/kg of body weight/day) for pulmonary exacerbation administered as thrice-daily short infusions or as a continuous infusion. The primary endpoint was the variation in the forced expiratory volume in 1 s (FEV1) during the course of antibiotic treatment. Sixty-nine of the 70 patients enrolled in the study received at least one course of antibiotic treatment. The improvement in FEV1 at the end of therapy was not statistically different between the two treatment procedures (+7.6% after continuous infusion and +5.5% after short infusions) but was better after continuous ceftazidime treatment in patients harboring resistant isolates (P < 0.05). The interval between the course of antibiotic treatments was longer after the continuous infusion than after the short infusion of ceftazidime (P = 0.04). The mean serum ceftazidime concentration during the continuous infusion was 56.2 +/- 23.2 microg/ml; the mean peak and trough concentrations during the short infusions were 216.3 +/- 71.5 and 12.1 +/- 8.7 microg/ml, respectively. The susceptibility profiles of the P. aeruginosa isolates remained unchanged and were similar for both regimens. Quality-of-life scores were similar whatever the treatment procedure, but 82% of the patients preferred the continuous-infusion regimen. Adverse events were not significantly different between the two regimens. In conclusion, the continuous infusion of ceftazidime did not increase its toxicity and appeared to be as efficient as short infusions in patients with cystic fibrosis as a whole, but it gave better results in patients harboring resistant isolates of P. aeruginosa.

Indinavir trough concentration as a determinant of early nephrolithiasis in HIV-1-infected adults.

Indinavir plasma levels are associated with antiretroviral efficacy; however, little data are available regarding toxicity. We assessed the relationship between indinavir pharmacokinetic (PK) characteristics and severe nephrolithiasis as well as other severe or serious adverse reactions. Patients included in the ANRS CO8 APROCO-COPILOTE cohort and receiving 800 mg indinavir three times daily as a first-line protease inhibitor were eligible for this study. To be included in the analysis, their plasma sample at month 1 (M1) had to be available (n = 282) to estimate using population PK modeling, indinavir PK characteristics, ie, maximum (Cmax) and trough plasma (Cres) concentrations, area under the curve (AUC), and observed/predicted concentration ratio (CR). A Cox model was used to estimate the independent effect of Cmax, Cres, AUC, and CR on the hazard of severe nephrolithiasis and serious adverse reactions. At M1, median Cmax was 6205 ng/mL, Cres 631 ng/mL, AUC 24,242 ng . h/mL, and CR 0.6. After a median follow up of 12 months, 11% of patients (30 of 282) had experienced at least one serious adverse reaction among which 12 were nephrolithiasis. In the multivariate analyses, early high indinavir Cres (ie, >/=1000 ng/mL at M1) was associated with a higher rate of severe nephrolithiasis (hazard ratio = 6.7; 95% confidence interval = 1.8-25.2; P < 0.01) and was also associated with a higher rate of all serious adverse reactions but only when nephrolithiasis were included among those cases. Prospective and early indinavir Cres determination should be recommended in the patient's care management and dosage adjustments.

Quantitative immunoassay to measure plasma and intracellular atazanavir levels: analysis of drug accumulation in cultured T cells.

We have developed an enzyme immunoassay to measure atazanavir (ATV) levels in plasma and cells. Anti-ATV polyclonal antibodies were raised in rabbits by using a synthetic ATV derivative coupled to bovine serum albumin as the immunogen, and the enzyme tracer was prepared by chemically coupling the ATV derivative with acetylcholinesterase. These reagents were used to develop a sensitive competitive enzyme immunoassay performed in microtitration plates, and the lowest limit of quantification was 150 pg/ml, which is about 10 times more sensitive than previously published techniques. The plasma assay was performed, after a simple methanol extraction, with a minimum of 30 microl of plasma. This assay showed good precision and efficiency, since the rates of recovery from human plasma and cell extracts spiked with ATV ranged form 93 to 113%, with coefficients of variation of less than 10%. ATV concentrations were measured in peripheral blood mononuclear cells incubated with various ATV concentrations and in CEM cells in the absence or presence of antiretroviral drugs and drug transporter inhibitors. The results indicated a dose-dependent uptake (intracellular concentration/extracellular concentration ratio range, 0.04 to 19). A significant increase in the accumulation of ATV was noticed in the presence of P-glycoprotein and MRP1 inhibitors (dipyridamole, inter alia). Interestingly, efavirenz significantly increased the baseline accumulation of ATV, whereas nevirapine induced a marked reduction. This new enzyme immunoassay for measuring plasma and intracellular ATV levels was fully validated and provides an inexpensive and useful tool for routine therapeutic drug monitoring. Moreover, in vitro results suggested the implication of drug transporters and interactions with other antiviral drugs that should be further explored in human immunodeficiency virus-infected patients.

Long-term treatment with lopinavir-ritonavir induces a reduction in peripheral adipose depots in mice.

Highly active antiretroviral therapy (HAART) of human immunodeficiency virus-infected patients is associated with adverse effects, such as lipodystrophy and hyperlipidemia. The lipodystrophic syndrome is characterized by a peripheral lipoatrophy and/or fat accumulation in the abdomen and neck. In order to get insights into the physiopathological mechanisms underlying this syndrome, we treated mice with protease inhibitors (PIs) over a long period of time. Although atazanavir-treated mice presented the same circulating triglyceride concentration as control mice, lopinavir-ritonavir-treated mice rapidly became hypertriglyceridemic, with triglyceride levels of 200 mg/dl, whereas control and atazanavir-treated animals had triglyceride levels of 80 mg/dl. These results obtained with mice reproduce the metabolic disorder observed in humans. White adipose tissue (WAT) was analyzed after 8 weeks of treatment. Compared to the control or atazanavir treatment, lopinavir-ritonavir treatment induced a significant 25% weight reduction in the peripheral inguinal WAT depot. By contrast, the profound epididymal WAT depot was not affected. This effect was associated with a 5.5-fold increase in SREBP-1c gene expression only in the inguinal depot. Our results demonstrate that the long-term treatment of mice with PIs constitutes an interesting experimental model with which some aspects of the lipoatrophy induced by HAART in humans may be studied.

Lopinavir/ritonavir combination and total/HDL cholesterol ratio.

OBJECTIVES: To describe the evolution of the lipidic profile among LPV/r treated patients in a 'real life' situation. METHODS: Lipids measurements at LPV/r initiation time and every 3 months, and pharmacological measurements at M3 and M6 were collected retrospectively in 142 patients attending our clinic. Dyslipidaemia was defined as total cholesterol > or =6.2 mmol/l, HDL-cholesterol > or =1 mmol/l, total/HDL-cholesterol ratio > or =6.5 and triglycerides > or =2.3 mmol/l. RESULTS: Eighty-nine percent of patients had previously received a regimen with protease inhibitors, 4% were treatment naive. At baseline, 17% of patients had high total cholesterol, 49% high triglycerides, 63% low HDL-cholesterol, 25% a high total/HDL-cholesterol ratio. At M12, the mean HDL-cholesterol increase per patient was 21%. Lipids levels significantly increased over the study period, as early as the 3rd month (6th month for ratio) and continuously until the 12th month. Among the patients with available LPV/r plasma determinations at M3, a higher lopinavir residual concentration was observed in those with high triglycerides (6.78 vs 3.02 mg/l, p = 0.05) as, at M6, in those with an elevated ratio (9.19 vs 0.96 mg/l, p = 0.02). CONCLUSIONS: Those results suggest that LPV/r may induce a significant rise in the total/HDL-cholesterol ratio, despite an increase in HDL-cholesterol levels. The association between triglycerides and total/HDL-cholesterol ratio elevated levels and high residual concentrations of lopinavir may also argue for systematic drug monitoring.