Monitoring drug therapy.

Drug development has improved over recent decades, with refinements in analytical techniques, population pharmacokinetic-pharmacodynamic (PK-PD) modelling and simulation, and new biomarkers of efficacy and tolerability. Yet this progress has not yielded improvements in individualization of treatment and monitoring, owing to various obstacles: monitoring is complex and demanding, many monitoring procedures have been instituted without critical assessment of the underlying evidence and rationale, controlled clinical trials are sparse, monitoring procedures are poorly validated and both drug manufacturers and regulatory authorities take insufficient account of the importance of monitoring. Drug concentration and effect data should be increasingly collected, analyzed, aggregated and disseminated in forms suitable for prescribers, along with efficient monitoring tools and evidence-based recommendations regarding their best use. PK-PD observations should be collected for both novel and established critical drugs and applied to observational data, in order to establish whether monitoring would be suitable. Methods for aggregating PK-PD data in systematic reviews should be devised. Observational and intervention studies to evaluate monitoring procedures are needed. Miniaturized monitoring tests for delivery at the point of care should be developed and harnessed to closed-loop regulated drug delivery systems. Intelligent devices would enable unprecedented precision in the application of critical treatments, i.e. those with life-saving efficacy, narrow therapeutic margins and high interpatient variability. Pharmaceutical companies, regulatory agencies and academic clinical pharmacologists share the responsibility of leading such developments, in order to ensure that patients obtain the greatest benefit and suffer the least harm from their medicines.

The impact of fasting on the interpretation of triglyceride levels for predicting myocardial infarction risk in HIV-positive individuals: the D:A:D study.

We assessed whether fasting modifies the prognostic value of these measurements for the risk of myocardial infarction (MI). Analyses used mixed effect models and Poisson regression. After confounders were controlled for, fasting triglyceride levels were, on average, 0.122 mmol/L lower than nonfasting levels. Each 2-fold increase in the latest triglyceride level was associated with a 38% increase in MI risk (relative rate, 1.38; 95% confidence interval, 1.26-1.51); fasting status did not modify this association. Our results suggest that it may not be necessary to restrict analyses to fasting measurements when considering MI risk.

On-line desorption of dried blood spot: A novel approach for the direct LC/MS analysis of micro-whole blood samples.

The aim of this work is to present a new concept, called on-line desorption of dried blood spots (on-line DBS), allowing the direct analysis of a dried blood spot coupled to liquid chromatography mass spectrometry device (LC/MS). The system is based on an inox cell which can receive a blood sample (10 microL) previously spotted on a filter paper. The cell is then integrated into LC/MS system where the analytes are desorbed out of the paper towards a column switching system ensuring the purification and separation of the compounds before their detection on a single quadrupole MS coupled to atmospheric pressure chemical ionisation (APCI) source. The described procedure implies that no pretreatment is necessary in spite the analysis is based on whole blood sample. To ensure the applicability of the concept, saquinavir, imipramine, and verapamil were chosen. Despite the use of a small sampling volume and a single quadrupole detector, on-line DBS allowed the analyses of these three compounds over their therapeutic concentrations from 50 to 500 ng/mL for imipramine and verapamil and from 100 to 1000 ng/mL for saquinavir. Moreover, the method showed good repeatability with relative standard deviation (RSD) lower than 15% based on two levels of concentration (low and high). Function responses were found to be linear over the therapeutic concentration for each compound and were used to determine the concentrations of real patient samples for saquinavir. Comparison of the founded values with those of a validated method used routinely in a reference laboratory showed a good correlation between the two methods. Moreover, good selectivity was observed ensuring that no endogenous or chemical components interfered with the quantitation of the analytes. This work demonstrates the feasibility and applicability of the on-line DBS procedure for bioanalysis.

ADME pharmacogenetics: investigation of the pharmacokinetics of the antiretroviral agent lopinavir coformulated with ritonavir.

BACKGROUND: An ADME (absorption, distribution, metabolism and excretion)-pharmacogenetics association study may identify functional variants relevant to the pharmacokinetics of lopinavir co-formulated with ritonavir (LPV/r), a first-line anti-HIV agent. METHODS: An extensive search of literature and web resources helped select ADME genes and single nucleotide polymorphisms (SNPs, functional and HapMap tagging SNPs) with a proven or potentially relevant role in LPV/r pharmacokinetics. The study followed a two-stage design. Stage 1 (discovery) considered a Caucasian population (n=638) receiving LPV/r, where we selected 117 individuals with low LPV clearance (cases) and 90 individuals with high clearance (controls). Genotyping was performed by a 1536-SNP customized GoldenGate Illumina BeadArray. Stage 2 (confirmation) represented a replication study of candidate SNPs from the stage 1 in 148 individuals receiving LPV/r. The analysis led to formal population pharmacokinetic-pharmacogenetic modeling of demographic, environmental and candidate SNP effects. RESULTS: One thousand three hundred and eighty SNPs were successfully genotyped. Nine SNPs prioritized by the stage 1 analysis were brought to replication. Stage 2 confirmed the contribution of two functional SNPs in SLCO1B1, one functional SNP in ABCC2 and a tag SNP of the CYP3A locus in addition to body weight effect and ritonavir coadministration. According to the population pharmacokinetic-pharmacogenetic model, genetic variants explained 5% of LPV variability. Individuals homozygous rs11045819 (SLCO1B1*4) had a clearance of 12.6 l/h, compared with 5.4 l/h in the reference group, and 3.9 l/h in individuals with two or more variant alleles of rs4149056 (SLCO1B1*5), rs717620 (ABCC2) or rs6945984 (CYP3A). A subanalysis confirmed that although a significant part of the variance in LPV clearance was attributed to fluctuation in ritonavir levels, genetic variants had an additional effect on LPV clearance. CONCLUSION: The two-stage strategy successfully identified genetic variants affecting LPV/r pharmacokinetics. Such a general approach of ADME pharmacogenetics should be generalized to other drugs.

Safety concerns about CCR5 as an antiviral target.

PURPOSE OF REVIEW: Clinical trials of CCR5 antagonists attest to their efficacy and tolerance in HIV treatment. However, there has been debate on their long-term safety because of the role of CCR5 in innate immunity. This review highlights gaps in our understanding of epidemiology of infections that are modulated by CCR5, in particular, in HIV-infected individuals. RECENT FINDINGS: In the mouse model, CCR5 has a role in the response against pathogens as diverse as Toxoplama gondii, West Nile virus, Mycobacterium tuberculosis, herpes simplex virus, Trypanosoma cruzi, Cryptococcus neoformans, Chlamydia trachomatis, Listeria, and plasmodia. In human cohorts, individuals carrying the defective CCR5Delta32 allele present an increased susceptibility to flavivirus (West Nile virus and tickborne encephalitis virus). The selective pressures that led to the spread of loss-of-function CCR5 mutations in humans (CCR5Delta32), and in mangabeys (CCR5Delta24) are not understood. SUMMARY: The recent availability of CCR5 antagonists has raised concern that genetic, biological, or chemical CCR5 knockout, although beneficial against some pathogens (i.e. HIV), could be deleterious for other processes implicated in pathogen response. The consequences of long-term pharmaceutical intervention on CCR5 should be carefully assessed through rigorous postmarketing surveillance.

Fistulizing Crohn's disease.

Fistulas are common in Crohn's disease. A population-based study has shown a cumulative risk of 33% after 10 years and 50% after 20 years. Perianal fistulas were the most common (54%). Medical therapy is the main option for perianal fistula once abscesses, if present, have been drained, and should include antibiotics (both ciprofloxacin and metronidazole) and immunomodulators. Infliximab should be reserved for refractory patients. Surgery is often necessary for internal fistulas.

Combined islet-lung transplantation in a cystic fibrosis patient.

The prevalence of insulin-dependent diabetes mellitus (IDDM) in cystic fibrosis patients ranges from 2 to 8% and glucose intolerance up to 15%. In recent years, lung transplantation has helped to prolong life expectancy of cystic fibrosis patients and represents 10 to 30% of all indications for lung transplantation. The postoperative need for immunosuppressive therapy using diabetogenic agents has decompensatory effects on glucose regulation and will probably increase the number of insulin-dependent cystic fibrosis patients. We report the case of an insulin-dependent cystic fibrosis patient transplanted with a combined islet-lung allograft. The pre-transplantation C-peptide level was below 0.04 nmol/l and preoperative insulin requirement was some 100 U per day. A sequential bipulmonary lung transplantation was performed and, using the pancreas of the same donor, we isolated and purified the islets of Langerhans by a modified automated method. We obtained 232,200 islets equivalent, which were injected into the liver by portal embolization. The postoperative course was uncomplicated, the insulin requirement decreased to 50% of the preoperative need and the C-peptide value increased to normal values and remained with the normal range during a follow-up period of 15 months. In conclusion, we believe that, besides type I diabetic patients, insulin-dependent cystic fibrosis patients with a negative C-peptide value could also be good candidates for combined islet-lung allotransplantation.

Severe transient neonatal lactic acidosis during prophylactic zidovudine treatment.

Zidovudine (ZDV) treatment during pregnancy, delivery and the postnatal period is effective in reducing the maternal-infant transmission of the human immunodeficiency virus. Reported adverse effects in the neonate during this longterm treatment are bone marrow suppression and elevation in aspartate aminotransferase activity. We report a case of severe ZDV-associated lactic acidosis in a neonate, which resolved rapidly following discontinuation of ZDV. The mechanisms leading to this side effect are poorly understood.

Delayed diagnosis of HIV infection and late initiation of antiretroviral therapy in the Swiss HIV Cohort Study.

OBJECTIVES: To investigate delayed HIV diagnosis and late initiation of antiretroviral therapy (ART) in the Swiss HIV Cohort Study. METHODS: Two sub-populations were included: 1915 patients with HIV diagnosis from 1998 to 2007 and within 3 months of cohort registration (group A), and 1730 treatment-naïve patients with CD4>or=200 cells/microL before their second cohort visit (group B). In group A, predictors for low initial CD4 cell counts were examined with a median regression. In group B, we studied predictors for CD4<200 cells/microL without ART despite cohort follow-up. RESULTS: Median initial CD4 cell count in group A was 331 cells/microL; 31% and 10% were <200 and <50 cells/microL, respectively. Risk factors for low CD4 count were age and non-White race. Homosexual transmission, intravenous drug use and living alone were protective. In group B, 30% initiated ART with CD4>or=200 cells/microL; 18% and 2% dropped to CD4 <200 and <50 cells/microL without ART, respectively. Sub-Saharan origin was associated with lower probability of CD4 <200 cells/microL without ART during follow-up. Median CD4 count at ART initiation was 207 and 253 cells/microL in groups A and B, respectively. CONCLUSIONS: CD4<200 cells/microL and, particularly, CD4<50 cells/microL before starting ART are predominantly caused by late presentation. Earlier HIV diagnosis is paramount.

When to initiate combined antiretroviral therapy to reduce mortality and AIDS-defining illness in HIV-infected persons in developed countries: an observational study.

BACKGROUND: Most clinical guidelines recommend that AIDS-free, HIV-infected persons with CD4 cell counts below 0.350 × 10(9) cells/L initiate combined antiretroviral therapy (cART), but the optimal CD4 cell count at which cART should be initiated remains a matter of debate. OBJECTIVE: To identify the optimal CD4 cell count at which cART should be initiated. DESIGN: Prospective observational data from the HIV-CAUSAL Collaboration and dynamic marginal structural models were used to compare cART initiation strategies for CD4 thresholds between 0.200 and 0.500 × 10(9) cells/L. SETTING: HIV clinics in Europe and the Veterans Health Administration system in the United States. PATIENTS: 20, 971 HIV-infected, therapy-naive persons with baseline CD4 cell counts at or above 0.500 × 10(9) cells/L and no previous AIDS-defining illnesses, of whom 8392 had a CD4 cell count that decreased into the range of 0.200 to 0.499 × 10(9) cells/L and were included in the analysis. MEASUREMENTS: Hazard ratios and survival proportions for all-cause mortality and a combined end point of AIDS-defining illness or death. RESULTS: Compared with initiating cART at the CD4 cell count threshold of 0.500 × 10(9) cells/L, the mortality hazard ratio was 1.01 (95% CI, 0.84 to 1.22) for the 0.350 threshold and 1.20 (CI, 0.97 to 1.48) for the 0.200 threshold. The corresponding hazard ratios were 1.38 (CI, 1.23 to 1.56) and 1.90 (CI, 1.67 to 2.15), respectively, for the combined end point of AIDS-defining illness or death. Limitations: CD4 cell count at cART initiation was not randomized. Residual confounding may exist. CONCLUSION: Initiation of cART at a threshold CD4 count of 0.500 × 10(9) cells/L increases AIDS-free survival. However, mortality did not vary substantially with the use of CD4 thresholds between 0.300 and 0.500 × 10(9) cells/L.

Higher CNS penetration-effectiveness of long-term combination antiretroviral therapy is associated with better HIV-1 viral suppression in cerebrospinal fluid.

OBJECTIVES: To determine HIV-1 RNA in cerebrospinal fluid (CSF) of successfully treated patients and to evaluate if combination antiretroviral treatments with higher central nervous system penetration-effectiveness (CPE) achieve better CSF viral suppression. METHODS: Viral loads (VLs) and drug concentrations of lopinavir, atazanavir, and efavirenz were measured in plasma and CSF. The CPE was calculated using 2 different methods. RESULTS: The authors analyzed 87 CSF samples of 60 patients. In 4 CSF samples, HIV-1 RNA was detectable with 43-82 copies per milliliter. Median CPE in patients with detectable CSF VL was significantly lower compared with individuals with undetectable VL: CPE of 1.0 (range, 1.0-1.5) versus 2.3 (range, 1.0-3.5) using the method of 2008 (P = 0.011) and CPE of 6 (range, 6-8) versus 8 (range, 5-12) using the method of 2010 (P = 0.022). The extrapolated CSF trough levels for atazanavir (n = 12) were clearly above the 50% inhibitory concentration (IC50) in only 25% of samples; both patients on atazanavir/ritonavir with detectable CSF HIV-1 RNA had trough levels in the range of the presumed IC50. The extrapolated CSF trough level for lopinavir (n = 42) and efavirenz (n = 18) were above the IC50 in 98% and 78%, respectively, of samples, including the patients with detectable CSF HIV-1 RNA. CONCLUSIONS: This study suggests that treatment regimens with high intracerebral efficacy reflected by a high CPE score are essential to achieve CSF HIV-1 RNA suppression. The CPE score including all drug components was a better predictor for treatment failure in the CSF than the sole concentrations of protease inhibitor or nonnucleoside reverse transcriptase inhibitor in plasma or CSF.

Systemic antibody responses to gut commensal bacteria during chronic HIV-1 infection.

BACKGROUND: Human systemic antibody responses to commensal microbiota are not well characterised during health and disease. Of particular interest is the analysis of their potential modulation caused by chronic HIV-1 infection which is associated with sustained enteropathy and systemic B cell disturbances reflected by impaired B cell responses and chronic B cell hyperactivity. The mechanisms underlying B cell hyperactivation and the specificities of the resulting hypergammaglobulinaemia are only poorly understood. METHODS: By a technique referred to as live bacterial FACS (fluorescence-activated cell sorting), the present study investigated systemic antibody responses to several gut and skin commensal bacteria as well as Candida albicans in longitudinal plasma and serum samples from healthy donors, chronic HIV-1-infected individuals with or without diarrhoea and patients with inflammatory bowel disease (IBD). RESULTS: The data show that systemic antibody responses to the commensal microbiota were abundantly present in humans and remained remarkably stable over years. Overall systemic antibody responses to gut commensal bacteria were not affected during chronic HIV-1 infection, with titres decreasing when normalised to elevated plasma immunoglobulin G (IgG) levels found in patients with HIV. In contrast, increases in the titres of high affinity antimicrobiota antibodies were detected in patients with IBD, demonstrating that conditions with known increased intestinal permeability and aberrant mutualism can induce changes in antibody titres observed in these assays. CONCLUSION: Neither HIV-associated enteropathy nor B cell dysfunction impact on the high-affinity systemic antibody responses to gut commensal bacteria. HIV-associated hypergammaglobulinaemia is therefore unlikely to be driven by induction of antimicrobiota antibodies.

Antiretroviral treatment of adult HIV infection: 2010 recommendations of the International AIDS Society-USA panel.

CONTEXT: Recent data regarding the consequences of untreated human immunodeficiency virus (HIV) infection and the expansion of treatment choices for antiretroviral-naive and antiretroviral-experienced patients warrant an update of the International AIDS Society-USA guidelines for the use of antiretroviral therapy in adults with HIV infection. OBJECTIVES: To provide updated recommendations for management of HIV-infected adults, using antiretroviral drugs and laboratory monitoring tools available in the international, developed-world setting. This report provides guidelines for when to initiate antiretroviral therapy, selection of appropriate initial regimens, patient monitoring, when to change therapy, and what regimens to use when changing. DATA SOURCES AND STUDY SELECTION: A panel with expertise in HIV research and clinical care reviewed relevant data published or presented at selected scientific conferences since the last panel report through April 2010. Data were identified through a PubMed search, review of scientific conference abstracts, and requests to antiretroviral drug manufacturers for updated clinical trials and adverse event data. DATA EXTRACTION AND SYNTHESIS: New evidence was reviewed by the panel. Recommendations were drafted by section writing committees and reviewed and edited by the entire panel. The quality and strength of the evidence were rated and recommendations were made by full panel consensus. CONCLUSIONS: Patient readiness for treatment should be confirmed before initiation of antiretroviral treatment. Therapy is recommended for asymptomatic patients with a CD4 cell count < or = 500/microL, for all symptomatic patients, and those with specific conditions and comorbidities. Therapy should be considered for asymptomatic patients with CD4 cell count > 500/microL. Components of the initial and subsequent regimens must be individualized, particularly in the context of concurrent conditions. Patients receiving antiretroviral treatment should be monitored regularly; treatment failure should be detected and managed early, with the goal of therapy, even in heavily pretreated patients, being HIV-1 RNA suppression below commercially available assay quantification limits.

Association of alcohol consumption and HIV surrogate markers in participants of the swiss HIV cohort study.

BACKGROUND: Alcohol consumption may affect the course of HIV infection and/or antiretroviral therapy (ART). The authors investigated the association between self-reported alcohol consumption and HIV surrogate markers in both treated and untreated individuals. DESIGN: Prospective cohort study. METHODS: Over a 7-year period, the authors analyzed 2 groups of individuals in the Swiss HIV Cohort Study: (1) ART-naïve individuals remaining off ART and (2) individuals initiating first ART. For individuals initiating first ART, time-dependent Cox proportional hazards models were used to assess the association between alcohol consumption, virological failure, and ART interruption. For both groups, trajectories of log-transformed CD4 cell counts were analyzed using linear mixed models with repeated measures. RESULTS: The authors included 2982 individuals initiating first ART and 2085 ART naives. In individuals initiating first ART, 241 (8%) experienced virological failure. Alcohol consumption was not associated with virological failure. ART interruption was noted in 449 (15%) individuals and was more prevalent in severe compared with none/light health risk drinkers [hazard ratio: 2.24, 95% confidence interval: 1.42 to 3.52]. The association remained significant even after adjusting for nonadherence. The authors did not find an association between alcohol consumption and change in CD4 cell count over time in either group. CONCLUSIONS: No effect of alcohol consumption on either virological failure or CD4 cell count in both groups of ART-initiating and ART-naive individuals was found. However, severe drinkers were more likely to interrupt ART. Efforts on ART continuation should be especially implemented in individuals reporting high alcohol consumption.