De-simplifying antiretroviral therapy from a single-tablet to a two-tablet regimen: Acceptance, patient-reported outcomes, and cost savings in a multicentre study.

BACKGROUND: Antiretroviral therapy (ART), which is increasingly used by people with HIV, accounts for significant care costs, particularly because of single-tablet regimens (STRs). This study explored de-simplification to a two-tablet regimen (TTR) for cost reduction. The objectives of this study were: (1) acceptance of de-simplification, (2) patient-reported outcomes, and (3) cost savings. METHODS: All individuals on Triumeq®, Atripla® or Eviplera® in five HIV clinics in the Netherlands were eligible. Healthcare providers informed individuals of this study. After inclusion, individuals were free to de-simplify. An electronic questionnaire was sent to assess study acceptance, adherence, quality of life (SF12) and treatment satisfaction (HIVTSQ). After 3 and 12 months, questionnaires were repeated. Cost savings were calculated using Dutch drug prices. RESULTS: In total, 283 individuals were included, of whom 55.5% agreed to de-simplify their ART, with a large variability between treatment centres: 41.1-74.2%. Individuals who were willing to de-simplify tended to be older, had a longer history of HIV diagnosis, and used more co-medication than those who preferred to remain on an STR regimen. Patient-reported outcomes, including quality of life and treatment satisfaction, showed no significant difference between people with HIV who switched to a TTR and those who remained on an STR regimen. Furthermore, we observed a 17.8% reduction in drug costs in our cohort of people with HIV who were initially on an STR. CONCLUSIONS: De-simplification from an STR to a TTR within the Dutch healthcare setting has been demonstrated as feasible, leads to significant cost reductions and should be discussed with every eligible person with HIV in the Netherlands.

GLP-1 agonists for people living with HIV and obesity, is there a potential?

BACKGROUND AND OBJECTIVES: Obesity trends and metabolic dysregulation are rising in people living with HIV using antiretrovirals (ARVs). Underlying causes and preventive strategies are being investigated. Two glucagon like-peptide 1 (GLP-1) agonists, liraglutide and semaglutide, were formerly approved as glucose-lowering drugs and have been recently approved for long-term weight loss in people with obesity. Due to the lack of therapeutic guidelines or clinical trials in people with HIV, we discuss the potential benefits, safety aspects and pharmacological considerations of prescribing liraglutide and semaglutide in people with HIV. RESULTS: Clinical experience is limited to two clinical cases of diabetic people with HIV using liraglutide after which a successful weight loss and glycaemic control were observed. None of the adverse events associated with liraglutide and semaglutide usage indicate an additional risk for people with HIV. Extra caution showed be warranted when initiating GLP-1 agonist therapy in people with HIV taking protease inhibitors who have pre-existing risk factors for heart rate variability to reduce the incidence of RP interval prolongation. GLP-1 agonists are metabolized by endopeptidases, and thus do not generate major drug-drug interactions with most drugs, including ARVs. GLP-s agonists are known to inhibit gastric acid secretion, which warrants caution and close monitoring when combined with atazanavir and oral rilpivirine, two ARVs that require low gastric pH for an optimal absorption. CONCLUSION: Theoretical considerations and a few available clinical observations support semaglutide and liraglutide prescription in people with HIV, with, thus far, no indications of concern regarding efficacy, safety or pharmacological interactions with ARVs.

Outcomes of modern antiretroviral therapy in obese individuals living with HIV.

Obesity is a global epidemic and people living with HIV (PLWH) are showing similar obesity trends to those in the general population. Obesity is manifested by several physiological features that can alter volume of distribution, elimination and metabolism of various medications including ART. Some drugs are increasingly prone to pharmacokinetic alteration during obesity depending on their physicochemical properties and clearance mechanism. These considerations raise concerns of hampered efficacy, development of resistance or increased toxicity of ART in PLWH. Here, we summarize available literature on the exposure and antiviral outcomes of currently available antiretroviral drugs in the context of obesity and provide a panel of recommendations for the clinical management and follow-up in this growing patient population.

The dolutegravir/valproic acid drug-drug interaction is primarily based on protein displacement.

OBJECTIVES: The dolutegravir/valproic acid drug-drug interaction (DDI) is suggested to be caused by protein displacement. Here, we assess the underlying mechanism. METHODS: Participants in a randomized controlled trial investigating valproic acid as an HIV latency reversing agent were recruited in a predefined pharmacokinetic substudy if they were on once-daily 50 mg dolutegravir-containing combination ART (cART) for >12 months with a plasma HIV-RNA <50 copies/mL (trial registration: ClinicalTrials.gov NCT03525730). Participants were randomized to receive 30 mg/kg/day valproic acid orally (divided into two equal doses) for 14 days or not. Total and unbound dolutegravir concentrations were measured on day 0 (before intake of valproic acid and 6 h after intake of valproic acid) and on days 1, 7, 14 and 42. Intra- and inter-subject dolutegravir concentrations and geometric means (GMs) were evaluated. RESULTS: Six of 10 participants on dolutegravir were randomized to receive valproic acid. During 14 days of valproic acid treatment, the GM total dolutegravir concentration decreased sharply from 1.36 mg/L on day 0 to 0.85, 0.31 and 0.20 mg/L on days 0, 1, 7 and 14, respectively, while total dolutegravir concentrations in the controls remained comparable during the same period: 1.27-1.49 mg/L. We observed a parallel increase in unbound dolutegravir fractions ranging from 0.39% to 0.58% during valproic acid administration, compared with 0.25% to 0.28% without valproic acid. Unbound dolutegravir concentrations were above the established in vitro EC90 value for unbound dolutegravir in 85% of the tested samples. CONCLUSIONS: This study confirms protein displacement as the main mechanism for this DDI, although additional mechanisms might be involved too. If dolutegravir is taken with food, this DDI is probably not clinically relevant.

Editor's Choice - Nationwide Analysis of Patients Undergoing Iliac Artery Aneurysm Repair in the Netherlands.

OBJECTIVE: The new 2019 guideline of the European Society for Vascular Surgery (ESVS) recommends consideration for elective iliac artery aneurysm (eIAA) repair when the iliac diameter exceeds 3.5 cm, as opposed to 3.0 cm previously. The current study assessed diameters at time of eIAA repair and ruptured IAA (rIAA) repair and compared clinical outcomes after open surgical repair (OSR) and endovascular aneurysm repair (EVAR). METHODS: This retrospective observational study used the nationwide Dutch Surgical Aneurysm Audit (DSAA) registry that includes all patients who undergo aorto-iliac aneurysm repair in the Netherlands. All patients who underwent primary IAA repair between 1 January 2014 and 1 January 2018 were included. Diameters at time of eIAA and rIAA repair were compared in a descriptive fashion. The anatomical location of the IAA was not registered in the registry. Patient characteristics and outcomes of OSR and EVAR were compared with appropriate statistical tests. RESULTS: The DSAA registry comprised 974 patients who underwent IAA repair. A total of 851 patients were included after exclusion of patients undergoing revision surgery and patients with missing essential variables. eIAA repair was carried out in 713 patients, rIAA repair in 102, and symptomatic IAA repair in 36. OSR was performed in 205, EVAR in 618, and hybrid repairs and conversions in 28. The median maximum IAA diameter at the time of eIAA and rIAA repair was 43 (IQR 38-50) mm and 68 (IQR 58-85) mm, respectively. Mortality was 1.3% (95% CI 0.7-2.4) after eIAA repair and 25.5% (95% CI 18.0-34.7) after rIAA repair. Mortality was not significantly different between the OSR and EVAR subgroups. Elective OSR was associated with significantly more complications than EVAR (intra-operative: 9.8% vs. 3.6%, post-operative: 34.0% vs. 13.8%, respectively). CONCLUSION: In the Netherlands, most eIAA repairs are performed at diameters larger than recommended by the ESVS guideline. These findings appear to support the recent increase in the threshold diameter for eIAA repair.

Predictors of virological failure in HIV-1-infected patients switching to dolutegravir maintenance monotherapy.

OBJECTIVES: The Dolutegravir Monotherapy for HIV (DOMONO; NCT02401828) study showed that maintenance monotherapy with dolutegravir (DTG) is associated with virological failure (VF) and leads to DTG resistance and as a result should not be used. However, data on clinical and virological factors associated with VF during DTG monotherapy are lacking. We identified factors associated with VF during DTG monotherapy. METHODS: A randomized trial was carried out in which patients on combination antiretroviral therapy (cART) with an HIV-1 RNA zenith < 100 000 copies/mL and a CD4 T-cell nadir ≥ 200 cells/µL, who had never experienced VF, switched to DTG monotherapy. Clinical and virological factors were compared between patients with and without VF, using univariate analyses. RESULTS: Eight of the 95 patients developed VF during DTG monotherapy. A total of 78 participants had reached week 48 when the study was discontinued. The median CD4 T-cell nadir was lower in patients with VF than in patients without VF [260 (interquartile range (IQR) 223-320) versus 380 (IQR 290-520) cells/µL, respectively; P = 0.011]. Patients with VF had a longer time between HIV diagnosis and cART initiation than those without VF [median 49 (IQR 27-64) versus 15 (IQR 1-38) months, respectively; P = 0.015]. The median total peripheral blood mononuclear cell (PBMC) HIV DNA copy number was higher in patients with VF than in those without VF [417 (range 85-4151) versus 147 (range 16-4132) copies/106 PBMCs, respectively; P = 0.022]. CONCLUSIONS: A lower CD4 nadir, a longer time between HIV diagnosis and cART initiation, and a higher HIV DNA copy number at the time of DTG monotherapy initiation were associated with VF. While there clearly is no future role for DTG monotherapy, ongoing and future studies on the efficacy of maintenance dual therapy (e.g. DTG lamivudine) may have to take these variables into account in their study design and analysis.

Pharmacokinetics of extended dose intervals of micafungin in haematology patients: optimizing antifungal prophylaxis.

Background: Extended dosing intervals for micafungin could overcome the need for hospitalization for antifungal prophylaxis. Objectives: This multicentre, open-label, randomized trial compared the pharmacokinetics of 300 mg of micafungin given twice weekly with 100 mg once daily as antifungal prophylaxis in adult haematology patients at risk of developing invasive fungal disease. Secondary objectives were assessment of adequate exposure with an alternative dosing regimen of micafungin (700 mg once weekly) through Monte Carlo simulations and assessment of safety in this patient population. Patients and methods: Twenty adult patients were randomized to receive either 300 mg of micafungin twice weekly or 100 mg once daily for 8 days. Blood samples were drawn daily and pharmacokinetic curves were determined on days 4/5 and 8. Monte Carlo simulations were performed for both investigated regimens as well as a frequently proposed alternative regimen (700 mg once weekly). Results: The predicted median AUC0-168h (IQR) for a typical patient on the investigated regimens of 100 mg once daily and 300 mg twice weekly and the hypothetical regimen of 700 mg once weekly were 690 (583-829), 596 (485-717) and 704 (585-833) mg·h/L, respectively. Conclusions: We observed comparable exposure with 300 mg of micafungin twice weekly and 100 mg of micafungin once daily. We provide the pharmacokinetic proof for an extended dosing regimen, which now needs to be tested in a clinical trial with hard endpoints.

Management of drug interactions with direct-acting antivirals in Dutch HIV/hepatitis C virus-coinfected patients: adequate but not perfect.

OBJECTIVES: Direct-acting antivirals (DAAs) for treatment of chronic hepatitis C virus (HCV) infection can cause drug-drug interactions (DDIs) with combination antiretroviral therapy (cART) and non-cART co-medication. We mapped how physicians manage DDIs between DAAs and co-medication and analysed treatment outcomes. METHODS: Data were prospectively collected as part of the ATHENA HIV observational cohort and retrospectively analysed. Dutch patients with HIV/HCV coinfection who initiated treatment with DAAs between January 2015 and May 2016 were included. Co-medication 3 months prior to and during DAA therapy was identified. Potential DDIs with the DAAs were checked using http://hep-druginteractions.org. DDIs were categorized as: (1) no interaction expected; (2) potential interaction; (3) contra-indication; (4) no recommendation. These categories were used to determine which patients switched or had a DDI during DAA therapy with co-medication. RESULTS: A total of 423 patients were treated with DAAs, of whom 418 (99%) used cART and 251 (59%) used non-cART co-medication. Before commencing DAA treatment, in 17 of 84 (20%) patients the non-cART co-medication which could result in a category 2/3 DDI was discontinued before DAA initiation, including two of six (33%) prescriptions of category 3 drugs. A total of 196 of 418 (47%) patients had a category 2/3 DDI between their DAA regimen and cART. Category 2/3 DDIs were prevented by switching cART in 78 of 147 (53%) and 47 of 49 (98%) patients. Overall, 367 of 423 (87%) patients have achieved a sustained virological response (33 in follow-up). CONCLUSIONS: Prescription patterns suggest that physicians are aware of potential DDIs between co-medication and DAAs, in particular potential DDIs with cART. Greater awareness is needed concerning category 3 interactions between non-cART co-medication and DAAs.

Paediatric European Network for Treatment of AIDS (PENTA) guidelines for treatment of paediatric HIV-1 infection 2015: optimizing health in preparation for adult life.

The 2015 Paediatric European Network for Treatment of AIDS (PENTA) guidelines provide practical recommendations on the management of HIV-1 infection in children in Europe and are an update to those published in 2009. Aims of treatment have progressed significantly over the last decade, moving far beyond limitation of short-term morbidity and mortality to optimizing health status for adult life and minimizing the impact of chronic HIV infection on immune system development and health in general. Additionally, there is a greater need for increased awareness and minimization of long-term drug toxicity. The main updates to the previous guidelines include: an increase in the number of indications for antiretroviral therapy (ART) at all ages (higher CD4 thresholds for consideration of ART initiation and additional clinical indications), revised guidance on first- and second-line ART recommendations, including more recently available drug classes, expanded guidance on management of coinfections (including tuberculosis, hepatitis B and hepatitis C) and additional emphasis on the needs of adolescents as they approach transition to adult services. There is a new section on the current ART 'pipeline' of drug development, a comprehensive summary table of currently recommended ART with dosing recommendations. Differences between PENTA and current US and World Health Organization guidelines are highlighted and explained.

Stallion semen quality depends on major histocompatibility complex matching to teaser mare.

The major histocompatibility complex (MHC) has repeatedly been found to influence mate choice of vertebrates, with MHC-dissimilar mates typically being preferred over MHC-similar mates. We used horses (Equus caballus) to test whether MHC matching also affects male investment into ejaculates after short exposure to a female. Semen characteristics varied much among stallions. Controlling for this variance with a full-factorial within-subject experimental design, we found that a short exposure to an MHC-dissimilar mare enhanced male plasma testosterone and led to ejaculates with elevated sperm numbers as compared to exposure to an MHC-similar mare. Sperm velocity seemed not affected by the treatment. Overall genetic similarity between stallions and mares (determined from polymorphic microsatellites on 20 different chromosomes) played no significant role here. The MHC type of the teaser mare also affected characteristics of cold-stored sperm after 24 and 48 hr. As expected from ejaculate economics, sperm viability was elevated after exposure to an MHC-dissimilar mare. However, oxidative stress and the percentage of sperm with a high DNA fragmentation were mostly increased after exposure to an MHC-dissimilar mare, depending also on whether the teaser mare was in oestrous or not. We conclude that males can quickly adjust ejaculate quality relative to a female's MHC, and that this male reaction to the social environment can also affect important characteristics of cold-stored semen.

Peg-interferon and ribavirin treatment in HIV/HCV co-infected patients in Thailand: efficacy, safety and pharmacokinetics.

OBJECTIVE: In Thailand, 7.2% of HIV patients are co-infected with hepatitis C virus (HCV), and these patients are treated with peg-interferon + ribavirin (PR) for their HCV infection. This study evaluates efficacy and safety of PR treatment and pharmacokinetics of ribavirin in this population. METHODS: HIV/HCV co-infected Thai patients were treated with PR for 24 or 48 weeks. Sustained virological response 24 weeks after the end of treatment (SVR24) was used to describe efficacy. (laboratory) safety parameters and ribavirin plasma concentrations were evaluated during study visits. Ribavirin concentrations were compared with t-tests for patients with and without anaemia (haemoglobin <10 g/dl) and SVR24. RESULTS: A total of 101 HIV/HCV co-infected patients were included; 88% were male (n = 88), and 46% were infected with genotype 3. The median (IQR) start dose was 14.28 mg/kg/day. SVR24 rate was 56%. All patients reported at least one (serious) adverse event, of which 28% of patients developed anaemia. Seven patients discontinued treatment due to toxicity issues. Geometric mean (IQR) ribavirin concentration was 1.81 (1.42-2.32) mg/l at week 8 of treatment. At week 8, patients with and without anaemia and SVR had ribavirin concentrations of 2.29 and 1.63 mg/l and 1.91 and 1.74 mg/l, respectively. CONCLUSIONS: PR treatment has comparable response rates and toxicity profile in Thai HIV/HCV co-infected patients as in Western HIV/HCV patients. However, ribavirin plasma concentrations were comparable with previously published studies in HIV/HCV co-infected patients, but both, just as SVR rate, were lower than in mono-infected patients.

A pharmacological rationale for improved everolimus dosing in oncology and transplant patients.

AIMS: Everolimus is a drug from the class of mammalian target of rapamycin inhibitors used for both immunosuppressant and oncological indications. We postulate that there is room for improvement of dosing, as the optimal immunosuppressive dose in calcineurin-free regimens is unknown and since the once daily dosing regimen for oncological indications is often associated with treatment-limiting toxicity. METHODS: We developed a mechanistic population pharmacokinetic model for everolimus in cancer and transplant patients and explored alternative dosing regimens. RESULTS: We found that formulation did not influence bioavailability and that use of >20 mg prednisolone daily increased everolimus clearance. In transplant patients, the approved dose of 0.75-1 mg twice daily (BID) results in subtherapeutic trough levels (<6 µg l-1 ) and that a higher starting dose of 2.25-3 mg BID is required. CONCLUSION: For oncological indications, our results encourage the investigation of dosing everolimus 3.75 mg BID in terms of superiority in safety and noninferiority in efficacy.

Major histocompatibility complex-linked social signalling affects female fertility.

Genes of the major histocompatibility complex (MHC) have been shown to influence social signalling and mate preferences in many species, including humans. First observations suggest that MHC signalling may also affect female fertility. To test this hypothesis, we exposed 191 female horses (Equus caballus) to either an MHC-similar or an MHC-dissimilar stimulus male around the time of ovulation and conception. A within-subject experimental design controlled for non-MHC-linked male characteristics, and instrumental insemination with semen of other males (n = 106) controlled for potential confounding effects of semen or embryo characteristics. We found that females were more likely to become pregnant if exposed to an MHC-dissimilar than to an MHC-similar male, while overall genetic distance to the stimulus males (based on microsatellite markers on 20 chromosomes) had no effect. Our results demonstrate that early pregnancy failures can be due to maternal life-history decisions (cryptic female choice) influenced by MHC-linked social signalling.

Daclatasvir 30 mg/day is the correct dose for patients taking atazanavir/cobicistat.

BACKGROUND: Atazanavir is boosted with the cytochrome P450 (CYP) 3A4 inhibitor ritonavir. When combined with the CYP3A4 substrate daclatasvir, the daclatasvir dosage should be reduced from 60 to 30 mg once daily. Recently, cobicistat was licensed as a CYP3A booster and used with atazanavir. OBJECTIVES: To determine whether the fixed-dose combination of atazanavir/cobicistat has an influence on daclatasvir pharmacokinetics comparable to that of the separate agents atazanavir and ritonavir. METHODS: A prospective, open-label, two-period, randomized, cross-over trial was performed in 16 healthy subjects (NCT02565888). Treatment consisted of 300/100 mg of atazanavir/ritonavir plus 30 mg of daclatasvir once daily (reference) and a second period of 300/150 mg of atazanavir/cobicistat plus 30 mg of daclatasvir once daily (test). A 24 h pharmacokinetic, steady-state curve was recorded for all drugs. Geometric mean ratios (GMRs) with 90% CI were calculated for daclatasvir and atazanavir AUCτ and Cmax to compare the effect of both treatments (test versus reference). Laboratory safety and adverse events were evaluated throughout the trial. RESULTS: All 16 healthy subjects completed the study. Median (range) age and BMI were 48.5 (21-55) years and 24.5 (19.0-29.2) kg/m2, respectively. Pharmacokinetic parameters of ritonavir and cobicistat were comparable to those in the literature. The GMRs (90% CI) of daclatasvir AUCτ and Cmax (test versus reference) were 101% (92%-111%) and 97% (89%-106%), respectively. Atazanavir GMRs (90% CI) of AUCτ and Cmax were 82% (75%-79%) and 74% (68%-81%), respectively. No serious adverse events were reported. CONCLUSIONS: Atazanavir/cobicistat and atazanavir/ritonavir had a similar influence on daclatasvir pharmacokinetics in healthy volunteers. Daclatasvir at 30 mg once daily is the correct dose when combined with atazanavir/cobicistat.

The farming environment protects mice from allergen-induced skin contact hypersensitivity.

BACKGROUND: Being born and raised in a farm provides a long-lasting protection for allergies. The microbial environment provided by farm animals is crucial to induce this protective effect, although underlying immune mechanisms remain elusive. OBJECTIVE: To establish a mouse model of global exposure to the farming environment and to study immunologic changes linked to protection of allergy. METHODS: Mice colonies were bred in parallel in a farm cowshed and the university animal facility (AF). Mice from both locations were subjected to a skin contact allergy model. Peripheral blood cells and cell cytokine production were assessed in both populations. In addition, the gut microbiome at various ages was characterized. RESULTS: Mice born in the farm were less prone to develop allergy than mice bred in the AF. Mice transfers between the AF and the farm showed a better protection when mice were moved to the farm early in life. As compared to AF-bred mice, farm mice displayed early immune activation with higher CD4+ T cell population, in particular CD4+ CD25+ FoxP3- (activated cells). The cytokine profile of mice from the farm was skewed towards an IL-17 and IL-22 secreting cell profile accompanied by increased IL-10 secretion. These differences were mostly seen within a specific age window between birth and 8 weeks of age. Microbiome analysis showed differences between 4 and 20 weeks old mice and between farm and AF mice with an increased number of Murine mastadenovirus B in young farm mice exclusively. CONCLUSION: The farming environment provides a strong, allergy protective IL-22 stimulus and generates activated CD4+ T cells. Exposure to the farm environment early in their life may also provide a better protection for contact skin allergy. Whether a viral trigger might decisively influence protection for allergies remains to be determined.

The Validity of a New Structured Assessment of Gastrointestinal Symptoms Scale (SAGIS) for Evaluating Symptoms in the Clinical Setting.

BACKGROUND: The clinical assessments of patients with gastrointestinal symptoms can be time-consuming, and the symptoms captured during the consultation may be influenced by a variety of patient and non-patient factors. To facilitate standardized symptom assessment in the routine clinical setting, we developed the Structured Assessment of Gastrointestinal Symptom (SAGIS) instrument to precisely characterize symptoms in a routine clinical setting. AIMS: We aimed to validate SAGIS including its reliability, construct and discriminant validity, and utility in the clinical setting. METHODS: Development of the SAGIS consisted of initial interviews with patients referred for the diagnostic work-up of digestive symptoms and relevant complaints identified. The final instrument consisted of 22 items as well as questions on extra intestinal symptoms and was given to 1120 consecutive patients attending a gastroenterology clinic randomly split into derivation (n = 596) and validation datasets (n = 551). Discriminant validity along with test-retest reliability was assessed. The time taken to perform a clinical assessment with and without the SAGIS was recorded along with doctor satisfaction with this tool. RESULTS: Exploratory factor analysis conducted on the derivation sample suggested five symptom constructs labeled as abdominal pain/discomfort (seven items), gastroesophageal reflux disease/regurgitation symptoms (four items), nausea/vomiting (three items), diarrhea/incontinence (five items), and difficult defecation and constipation (2 items). Confirmatory factor analysis conducted on the validation sample supported the initially developed five-factor measurement model ([Formula: see text], p < 0.0001, χ 2/df = 4.6, CFI = 0.90, TLI = 0.88, RMSEA = 0.08). All symptom groups demonstrated differentiation between disease groups. The SAGIS was shown to be reliable over time and resulted in a 38% reduction of the time required for clinical assessment. CONCLUSIONS: The SAGIS instrument has excellent psychometric properties and supports the clinical assessment of and symptom-based categorization of patients with a wide spectrum of gastrointestinal symptoms.

Hepatic cyst penetration of cefazolin in patients receiving aspiration sclerotherapy.

BACKGROUND: Hepatic cyst infection is a potentially severe complication in cystic disease. Treatment demands effective antibiotic concentrations within the infected cyst. OBJECTIVES: The aim of this study was to use elective hepatic cyst drainage as a unique pharmacokinetic model to investigate whether cefazolin, a first-generation cephalosporin, is able to penetrate hepatic cysts. PATIENTS AND METHODS: Patients scheduled to undergo percutaneous aspiration sclerotherapy of a symptomatic non-infected, non-neoplastic hepatic cyst were eligible for this study. All participants received a single perioperative prophylactic dose of cefazolin (1000 mg, intravenously). We collected blood and cyst fluid samples to determine total and unbound cefazolin concentrations using HPLC. The primary outcome was hepatic cyst penetration, expressed as the ratio (%) of unbound concentration of cefazolin in cyst fluid to plasma (both in mg/L). RESULTS: We included eight patients [male = 25%, median age = 60 years (IQR 54-75), median estimated glomerular filtration rate = 97 mL/min/1.73 m(2) (IQR 67-102) and median serum albumin = 40 g/L (IQR 37-40)]. We detected low concentrations of unbound cefazolin in cyst fluid (≤1.0 mg/L). The median plasma unbound cefazolin peak level (immediately after cefazolin administration) was 36.6 mg/L (IQR 23.7-54.1) and the level at the time of cyst fluid aspiration was 16.1 mg/L (IQR 13.0-20.1). In total, the hepatic cyst penetration of free cefazolin was only 2.2% (IQR 0.7-5.2). CONCLUSIONS: We developed a study model to investigate the penetration of antibiotics into hepatic cysts. Cefazolin did not reach adequate intracystic concentrations. Future studies should explore alternatives.

A world-wide survey and field study in clinical haemostasis laboratories to evaluate FVIII:C activity assay variability of ADYNOVATE and OBIZUR in comparison with ADVATE.

INTRODUCTION: Discrepancies have been previously reported for one-stage clotting and chromogenic assays for FVIII activity analysis. Inter-laboratory variations in instruments, method of clot detection, assay set-up, reference standard calibration, reagent source and reagent composition all contribute to assay variability. AIM: To characterise multilaboratory assay variability in measuring ADYNOVATE, OBIZUR and ADVATE FVIII activity in human plasma and survey multinational FVIII activity assay preferences. METHODS: As samples from patients treated with either of the FVIII products are not available in the quantities required for a systematic collaborative study, haemophilia A plasma was spiked in vitro with either ADYNOVATE (PEGylated rFVIII), OBIZUR [Porcine Sequence Antihaemophilic Factor (Recombinant)] or ADVATE at high (0.80 IU or U mL-1 ), medium (0.20 IU or U mL-1 ) and low (0.05 IU or U mL-1 ) FVIII concentrations, based on labelled potencies. Clinical laboratories used their routine FVIII activity assay to determine FVIII activity of each product. Thirty-five data sets using one-stage clotting assay and 11 sets using chromogenic assay were obtained. RESULTS: A vast majority of laboratories (98%) prefer and rely on the one-stage clotting assay. Mean recoveries across all concentrations were 113%, 120% and 127% for ADYNOVATE, OBIZUR and ADVATE respectively. Assay variation was comparable between ADVATE, ADYNOVATE and OBIZUR with inter-laboratory percent coefficients of variation (%CV) ranging from 11 to 22%. Mean chromogenic assay results were 116%, 51% and 113% for ADYNOVATE, OBIZUR and ADVATE respectively. Inter-laboratory CV's were similar for ADYNOVATE, OBIZUR and ADVATE. CONCLUSIONS: One-stage clotting assays can and will be used with sufficient accuracy and precision for the measurement of ADYNOVATE, OBIZUR and ADVATE in plasma samples from subjects with haemophilia A. Chromogenic assay underestimates OBIZUR potency, particularly at lower concentrations.

Synovial fluid proteins are required for the induction of interleukin-1ß production by monosodium urate crystals.

OBJECTIVES: Monosodium urate (MSU) crystal deposition in gouty joints promotes the release of inflammatory mediators, in particular interleukin (IL)-1ß. The induction of IL-1ß production by MSU crystals requires a co-stimulus. The objective of this study was to determine which part of the synovial fluid (SF) provides co-stimulation to MSU crystals to induce IL-1ß in macrophages. METHOD: The lipidic fraction (LF) and the protein fraction (PF) were isolated from the SF of patients with arthropathies. The PF was subfractionated according to different molecular weight (MW) ranges. THP-1 cells or human primary monocytes were stimulated with MSU crystals in the presence or absence of SF or SF fractions. IL-1ß and IL-8 production and IL-1ß mRNA expression were assessed by an enzyme-linked immunosorbent assay (ELISA) and quantitative real-time polymerase chain reaction (qPCR). RESULTS: Exposure of monocytes/macrophages to MSU crystals alone induced the moderate release of IL-8 but not of IL-1ß. The production of IL-1ß required the presence of both SF from patients with inflammatory arthritis (SFi) and MSU crystals. SF from patients with non-inflammatory arthritis, that is patients with osteoarthritis (OA), did not affect the IL-1ß production but slightly enhanced the secretion of IL-8. Both MSU crystals and SFi were required for the induction of the IL-1ß transcript, which was not expressed in the presence of either stimulus alone. SFi fractionation demonstrated that the MSU crystal co-stimulus was contained in the PF of SFi with MW > 50 kDa but not in the LF. CONCLUSIONS: This study shows that the SF of inflammatory arthritis patients, including gout patients, contains proteins required for the induction of IL-1ß by MSU crystals in macrophages whereas lipids are not involved.

The effect of dipyridamole on the pharmacokinetics of metformin: a randomized crossover study in healthy volunteers.

PURPOSE: Concomitant treatment with the glucose-lowering drug metformin and the platelet aggregation inhibitor dipyridamole often occurs in patients with type 2 diabetes mellitus who have suffered a cerebrovascular event. The gastrointestinal uptake of metformin is mediated by the human equilibrative nucleoside transporter 4 (ENT4), which is inhibited by dipyridamole in preclinical studies. We hypothesized that dipyridamole lowers the plasma exposure to metformin. METHODS: Eighteen healthy volunteers (mean age 23 years; 9 male) were randomized in an open-label crossover study. Subjects were allocated to treatment with metformin 500 mg twice daily in combination with dipyridamole slow-release 200 mg twice daily or to metformin alone for 4 days. After a washout period of 10 days, the volunteers were crossed over to the alternative treatment arm. Blood samples were collected during a 10-h period after intake of the last metformin dose. The primary endpoint was the area under the plasma concentration-time curve (AUC0-12h) and the maximum plasma metformin concentration (C max). RESULTS: In healthy subjects, dipyridamole did not significantly affect Cmax nor AUC0-12h of metformin under steady-state conditions. CONCLUSIONS: Previous in vitro studies report that dipyridamole inhibits the ENT4 transporter that mediates gastrointestinal uptake of metformin. In contrast, co-administration of dipyridamole at therapeutic dosages to healthy volunteers does not have a clinically relevant effect on metformin plasma steady-state exposure. This observation is reassuring for patients who are treated with this combination of drugs.