Publications by authors named "Walthere Dewe"

A recombinant respiratory syncytial virus (RSV) fusion glycoprotein candidate vaccine (RSV-PreF) manufactured in Chinese hamster ovary cells was developed for immunization of pregnant women, to protect newborns against RSV disease through trans-placental antibody transfer. Traces of a host-cell protein, hamster neogenin (haNEO1), were identified in purified RSV-PreF antigen material. Given the high amino-acid sequence homology between haNEO1 and human neogenin (huNEO1), there was a risk that potential vaccine-induced anti-neogenin immunity could affect huNEO1 function in mother or fetus.

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One of the main factors defining intestinal drug absorption is the solubility of the compound in the gastrointestinal environment. This study reports the solubility of a series of 27 commonly used acidic, neutral and basic drugs in human intestinal fluid samples collected from the duodenum or jejunum of healthy volunteers under fasted state conditions. The interindividual variability as well as the impact of factors such as pH, sampling site and bile salts on the solubility in human intestinal fluids was investigated.

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We investigated the role of AS03 (here AS03), an α-tocopherol oil-in-water emulsion-based adjuvant system, on the long-term persistence of humoral and cell-mediated immune responses to A(H1N1)pdm09 influenza vaccines. In two studies, a total of 261 healthy adults (≤60 years old) were randomized to receive two doses of AS03-adjuvanted vaccine containing 3.75 μg of hemagglutinin (HA) or nonadjuvanted vaccine containing 15 μg of hemagglutinin (in study A) or 3.

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Background:  Respiratory syncytial virus (RSV) is a leading cause of childhood bronchiolitis and pneumonia, particularly in early infancy. Immunization of pregnant women could boost preexisting immune responses, providing passive protection to newborns through placental transfer of anti-RSV antibody.

Methods:  In this first-in-humans clinical trial of a purified recombinant RSV protein F vaccine engineered to preferentially maintain prefusion conformation (RSV-PreF), 128 healthy men 18-44 years old were randomized to one dose of a RSV-PreF vaccine containing 10, 30, or 60 µg of RSV-PreF antigen, with or without alum adjuvant, or control, and followed for one year for safety and immunogenicity outcomes.

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In this study we describe the immunogenicity results from a subset of older people (N = 5187) who participated in a Phase 3 randomized, observer-blinded trial of AS03-TIV versus TIV (Fluarix™) (ClinicalTrials.gov, NCT00753272). Participants received one dose of AS03-TIV or TIV in each study year and antibody titers against the vaccine strains were assessed using hemagglutination-inhibition (HI) assay at 21 d and 180 d post-vaccination in each vaccine group in the 2008/09 (Year 1) and 2009/10 (Year 2) influenza seasons.

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In retrospective observational studies, an increased relative risk of incident narcolepsy was observed in some European countries among recipients of the AS03-adjuvanted, A(H1N1)pdm09, inactivated, detergent-split virion vaccine Pandemrix™ manufactured in Dresden, Germany (D-Pan H1N1). A similar increased risk was not observed in a retrospective population-based study in individuals in Quebec province, Canada, who received Aprepanrix™, a Quebec-manufactured AS03-adjuvanted A(H1N1)pdm09 inactivated, detergent-split virion vaccine (Q-Pan H1N1). Antibody responses in D-Pan versus Q-Pan vaccinees (adults/children) measured as hemagglutination inhibition (HI) titers 21 d post-vaccination were found to be equivalent (NCT01161160).

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Background.  To investigate the relationship between hemagglutinin-inhibition (HI) antibody levels to the risk of influenza disease, we conducted a correlate of protection analysis using pooled data from previously published randomized trials. Methods.

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The success of a seasonal influenza vaccine efficacy trial depends not only upon the design but also upon the annual epidemic characteristics. In this context, simulation methods are an essential tool in evaluating the performances of study designs under various circumstances. However, traditional methods for simulating time-to-event data are not suitable for the simulation of influenza vaccine efficacy trials because of the seasonality and heterogeneity of influenza epidemics.

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This article illustrates the use of a multi-criteria decision making approach, based on desirability functions, to identify an appropriate adjuvant composition for an influenza vaccine to be used in elderly. The proposed adjuvant system contained two main elements: monophosphoryl lipid and α-tocopherol with squalene in an oil/water emulsion. The objective was to elicit a stronger immune response while maintaining an acceptable reactogenicity and safety profile.

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Clinical trials have shown that AS03-adjuvanted H5N1 and A(H1N1)pdm09 vaccines are highly immunogenic, although with an increased reactogenicity profile relative to non-adjuvanted vaccines in terms of the incidence of common injection site and systemic adverse events (AEs). We evaluated pooled safety data from 22,521 adults who had received an AS03-adjuvanted H5N1 or A(H1N1)pdm09 influenza or control vaccine with the purpose to identify medically-attended AEs (MAEs), including subsets of serious AEs (SAEs), potentially immune-mediated diseases (pIMDs), and AEs of special interest (AESI), and to explore a potential association of these AEs with the administration of an AS03-adjuvanted influenza vaccine. For participants who had received an AS03-adjuvanted vaccine, the relative risks (RRs) for experiencing a MAE or a SAE compared to control group (participants who had received a non-adjuvanted vaccine or saline placebo) were 1.

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Background: Two influenza B lineages have been co-circulating since the 1980s, and because inactivated trivalent influenza vaccine (TIV) contains only one B strain, it provides little/no protection against the alternate B-lineage. We assessed a candidate inactivated quadrivalent influenza vaccine (QIV) containing both B lineages versus TIV in healthy adults.

Methods: Subjects received one dose of QIV (lot 1, 2, or 3) or one of two TIVs (B strain from Victoria or Yamagata lineage); randomization was 2:2:2:1:1.

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The efficacy assessment of an influenza vaccine often requires conducting large and expensive clinical trials. Specificities of influenza increase the complexity of the study designs, of the subsequent statistical analysis and of the interpretation of the results. They include low attack rates, seasonality, multiplicity and frequent mutations of flu viruses as well as heterogeneity of virus circulation, varying annual vaccine composition and so on.

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Background: Improved influenza vaccines are needed to reduce influenza-associated complications in older adults. The aim of this study was to identify the optimal formulation of adjuvanted seasonal influenza vaccine for use in elderly people.

Methods: This observer-blind, randomized study assessed the optimal formulation of adjuvanted seasonal influenza vaccine based on immunogenicity and safety in participants aged ≥65 years.

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Background: Mismatch between circulating influenza B viruses (Yamagata and Victoria lineages) and vaccine strains occurs frequently.

Methods: In a randomized controlled trial, immunogenicity and safety of an inactivated quadrivalent influenza vaccine candidate (QIV) versus trivalent inactivated influenza vaccine (TIV)-Victoria(Vic) and TIV-Yamagata(Yam) in children 3-17 years of age was evaluated. In an open-label study arm, QIV only was assessed in children 6-35 months of age.

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Background: Two phylogenetic lineages of influenza B virus coexist and circulate in the human population (B/Yamagata and B/Victoria) but only one B-strain is included in each seasonal vaccine. Mismatch regularly occurs between the recommended and circulating B-strain. Inclusion of both lineages in vaccines may offer better protection against influenza.

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The influence of AS03(A), a tocopherol oil-in-water emulsion-based adjuvant system, on humoral and cell-mediated responses to A/California/7/2009 H1N1 pandemic vaccine was investigated. In two observer-blind studies, a total of 261 healthy adults aged 18 to 60 years were randomized to receive either AS03(A)-adjuvanted H1N1 vaccine containing 3.75 μg hemagglutinin (HA) or nonadjuvanted H1N1 vaccine containing 15 or 3.

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Background: This study (NCT00383123) compared the immunogenicity and safety of 2 trivalent inactivated influenza vaccines: Fluarix [GlaxoSmithKline (study vaccine)] and Fluzone [Sanofi Pasteur (control vaccine)] in children 6 months to <18 years.

Methods: Children, stratified by age and randomized, received either study (N = 2115) or control vaccine (N = 1210) at day 0 (and day 28 for previously unvaccinated children younger than 9 years). Children 6 months to <5 years comprised the according-to-protocol (ATP) cohort for immunogenicity, whereas the reactogenicity/safety group included all children 6 months to <18 years.

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Review of statistical methodologies used to compare (bio)assays.

J Chromatogr B Analyt Technol Biomed Life Sci

August 2009

At any phase of the development of a drug or a vaccine, scientists need to compare different (bio)assays. The objective of this paper is to review different statistical methodologies that could be used to assess the equivalence between methods. Depending on the objective (average or individual equivalence), depending on the design, several approaches are detailed: two one-sided t-tests, concordance correlation coefficient, limits of agreement, tolerance intervals and probabilistic approach.

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The investigation of compliance in patients with major depressive disorder (in drop-outs versus completers and in first episode versus recurrent episode patients). A total of 85 outpatients with major depressive disorder were followed for 6 months. Different dimensions of compliance were investigated: drop-outs versus completers and their medication adherence (with electronic monitoring).

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The lead optimization phase of drug discovery requires high-throughput analyses for quantification in biological matrices and in plasma in particular. Over the last decade, some technical innovations allowed the pharmaceutical industry to improve the quality of the results. However, there is room for improvement.

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It is recognized that the purpose of validation of analytical methods is to demonstrate that the method is suited for its intended purpose. Validation is not only required by regulatory authorities, but is also a decisive phase before the routine use of the method. For a quantitative analytical method the objective is to quantify the target analytes with a known and suitable accuracy.

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Objective: Although adverse events are a key factor in compliance, their evolution during treatment with antidepressants is poorly documented. Therefore, the time course of adverse events during 6 months of antidepressant treatment was investigated.

Method: 85 psychiatric outpatients with a DSM-IV diagnosis of major depressive disorder (with the exclusion of other DSM-IV Axis I disorders) were enrolled between September 2002 and March 2003 in a multicenter, randomized, double-blind trial with selective serotonin reup-take inhibitors (fluoxetine [N = 42] and paroxetine [N = 43]).

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The influence on the enantiomeric resolution of the nature of the cationic BGE component (sodium, ammonium or potassium) and that of the anionic component (chloride, formate, methanesulfonate or camphorsulfonate) as well as the concentration of heptakis(2,3-di-O-methyl-6-O-sulfo)-beta-cyclodextrin (HDMS-beta-CD), the selected chiral selector, was studied in nonaqueous capillary electrophoresis (NACE). For this purpose, two D-optimal designs with 33 and 26 experimental points were applied. Three beta-blockers (atenolol, celiprolol and propranolol) and three local anesthetics (bupivacaine, mepivacaine and prilocaine) were selected as basic model compounds.

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The implementation of quality systems in analytical laboratories has now, in general, been achieved. While this requirement significantly modified the way that the laboratories were run, it has also improved the quality of the results. The key idea is to use analytical procedures which produce results that fulfil the users' needs and actually help when making decisions.

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