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1.
Hum Reprod Open ; 2022(4): hoac054, 2022.
Article in English | MEDLINE | ID: mdl-36518987

ABSTRACT

STUDY QUESTION: What is the association between serum progesterone levels on the day of frozen embryo transfer (FET) and the probability of live birth in women undergoing different FET regimens? SUMMARY ANSWER: Overall, serum progesterone levels <7.8 ng/ml were associated with reduced odds of live birth, although the association between serum progesterone levels and the probability of live birth appeared to vary according to the route of progesterone administration. WHAT IS KNOWN ALREADY: Progesterone is essential for pregnancy success. A recent systematic review showed that in FET cycles using vaginal progesterone for endometrial preparation, lower serum progesterone levels (<10 ng/ml) were associated with a reduction in live birth rates and higher chance of miscarriage. However, there was uncertainty about the association between serum progesterone levels and treatment outcomes in natural cycle FET (NC-FET) and HRT-FET using non-vaginal routes of progesterone administration. STUDY DESIGN SIZE DURATION: This was a multicentre (n = 8) prospective cohort study conducted in the UK between January 2020 and February 2021. PARTICIPANTS/MATERIALS SETTING METHODS: We included women having NC-FET or HRT-FET treatment with progesterone administration by any available route. Women underwent venepuncture on the day of embryo transfer. Participants and clinical personnel were blinded to the serum progesterone levels. We conducted unadjusted and multivariable logistic regression analyses to investigate the association between serum progesterone levels on the day of FET and treatment outcomes according to the type of cycle and route of exogenous progesterone administration. Our primary outcome was the live birth rate per participant. MAIN RESULTS AND THE ROLE OF CHANCE: We studied a total of 402 women. The mean (SD) serum progesterone level was 14.9 (7.5) ng/ml. Overall, the mean adjusted probability of live birth increased non-linearly from 37.6% (95% CI 26.3-48.9%) to 45.5% (95% CI 32.1-58.9%) as serum progesterone rose between the 10th (7.8 ng/ml) and 90th (24.0 ng/ml) centiles. In comparison to participants whose serum progesterone level was ≥7.8 ng/ml, those with lower progesterone (<7.8 ng/ml, 10th centile) experienced fewer live births (28.2% versus 40.0%, adjusted odds ratio [aOR] 0.41, 95% CI 0.18-0.91, P = 0.028), lower odds of clinical pregnancy (30.8% versus 45.1%, aOR 0.36, 95% CI 0.16-0.79, P = 0.011) and a trend towards increased odds of miscarriage (42.1% versus 28.7%, aOR 2.58, 95% CI 0.88-7.62, P = 0.086). In women receiving vaginal progesterone, the mean adjusted probability of live birth increased as serum progesterone levels rose, whereas women having exclusively subcutaneous progesterone experienced a reduction in the mean probability of live birth as progesterone levels rose beyond 16.3 ng/ml. The combination of vaginal and subcutaneous routes appeared to exert little impact upon the mean probability of live birth in relation to serum progesterone levels. LIMITATIONS REASONS FOR CAUTION: The final sample size was smaller than originally planned, although our study was adequately powered to confidently identify a difference in live birth between optimal and inadequate progesterone levels. Furthermore, our cohort did not include women receiving oral or rectal progestogens. WIDER IMPLICATIONS OF THE FINDINGS: Our results corroborate existing evidence suggesting that lower serum progesterone levels hinder FET success. However, the relationship between serum progesterone and the probability of live birth appears to be non-linear in women receiving exclusively subcutaneous progesterone, suggesting that in this subgroup of women, high serum progesterone may also be detrimental to treatment success. STUDY FUNDING/COMPETING INTERESTS: This work was supported by CARE Fertility and a doctoral research fellowship (awarded to P.M.) by the Tommy's Charity and the University of Birmingham. M.J.P. is supported by the NIHR Birmingham Biomedical Research Centre. S.F. is a minor shareholder of CARE Fertility but has no financial or other interest with progesterone testing or manufacturing companies. P.L. reports personal fees from Pharmasure, outside the submitted work. G.P. reports personal fees from Besins Healthcare, outside the submitted work. M.W. reports personal fees from Ferring Pharmaceuticals, outside the submitted work. The remaining authors have no conflict of interest to declare. TRIAL REGISTRATION NUMBER: ClinicalTrials.gov: NCT04170517.

2.
Fertil Steril ; 116(6): 1534-1556, 2021 12.
Article in English | MEDLINE | ID: mdl-34384594

ABSTRACT

OBJECTIVE: To investigate the association between luteal serum progesterone levels and frozen embryo transfer (FET) outcomes. DESIGN: Systematic review and meta-analysis. SETTING: Not applicable. PATIENT(S): Women undergoing FET. INTERVENTION(S): We conducted electronic searches of MEDLINE, PubMed, CINAHL, EMBASE, the Cochrane Database of Systematic Reviews, Cochrane Central Register of Controlled Trials, Web of Science, ClinicalTrials.gov, and grey literature (not widely available) from inception to March 2021 to identify cohort studies in which the serum luteal progesterone level was measured around the time of FET. MAIN OUTCOME MEASURE(S): Ongoing pregnancy or live birth rate, clinical pregnancy rate, and miscarriage rate. RESULT(S): Among the studies analyzing serum progesterone level thresholds <10 ng/mL, a higher serum progesterone level was associated with increased rates of ongoing pregnancy or live birth (relative risk [RR] 1.47, 95% confidence interval [CI] 1.28 to 1.70), higher chance of clinical pregnancy (RR 1.31, 95% CI 1.16 to 1.49), and lower risk of miscarriage (RR 0.62, 95% CI 0.50 to 0.77) in cycles using exclusively vaginal progesterone and blastocyst embryos. There was uncertainty about whether progesterone thresholds ≥10 ng/mL were associated with FET outcomes in sensitivity analyses including all studies, owing to high interstudy heterogeneity and wide CIs. CONCLUSION(S): Our findings indicate that there may be a minimum clinically important luteal serum concentration of progesterone required to ensure an optimal endocrine milieu during embryo implantation and early pregnancy after FET treatment. Future clinical trials are required to assess whether administering higher-dose luteal phase support improves outcomes in women with a low serum progesterone level at the time of FET. PROSPERO NUMBER: CRD42019157071.


Subject(s)
Cryopreservation/trends , Embryo Transfer/trends , Luteal Phase/blood , Pregnancy Rate/trends , Progesterone/blood , Reproductive Techniques, Assisted/trends , Embryo Transfer/methods , Female , Humans , Live Birth/epidemiology , Pregnancy , Prospective Studies , Retrospective Studies
3.
J Pharmacokinet Pharmacodyn ; 48(2): 295-303, 2021 Apr.
Article in English | MEDLINE | ID: mdl-33389522

ABSTRACT

Obtaining a good prior for the linear pharmacokinetics of new monoclonal antibodies (mAbs) would be an advantage not only for designing first-in-human (FIH) studies but also for stabilizing fitting of data with non-linear target-mediated disposition models. We estimated the pharmacokinetics from FIH studies for five mAbs using a two-compartment model, both separately and together, using a simple pool, a third hierarchical level of random effects for between mAb differences and non-human-primate half-lives as a predictor covariate for said differences. There was good agreement between compounds for the rapidly accessible central volume of 2.9 L (70 kg human), but clearances and peripheral volumes differed with terminal half-lives ranging from 15 to 28 days. The simple pool of human studies gave inter-individual variability estimates of 32% coefficient of variation (CV) for clearance and 33% CV for peripheral volume, larger than for separate fits (13-26% CV and 15-35% CV for clearance and volume respectively). Using third level hierarchical random effects gave inter-individual variability estimates close to those of separate fits (24% and 16% CV respectively). The between-mAb differences became predictable if non-human primate body weight scaled terminal half-life estimates were included as covariates on clearance and peripheral volume. In conclusion, ignoring inter-mAb variation leads to inflated estimates of inter-individual variability and unrealistic simulations for FIH studies. However, by using 70 kg body weight scaled terminal half-life estimates from non-human primates one can account for between-mAb differences and provide non-inflated priors for the linear pharmacokinetic parameters of new mAbs.


Subject(s)
Antibodies, Monoclonal/pharmacokinetics , Models, Biological , Animals , Antibodies, Monoclonal/administration & dosage , Body Weight , Callithrix , Clinical Trials, Phase I as Topic , Datasets as Topic , Drug Evaluation, Preclinical/methods , Half-Life , Humans , Linear Models , Macaca fascicularis
4.
Xenobiotica ; 49(1): 13-21, 2019 Jan.
Article in English | MEDLINE | ID: mdl-29299977

ABSTRACT

1. The utility of 1-aminobenzotriazole (ABT), incorporated in food, has been investigated as an approach for longer term inhibition of cytochrome P450 (P450) enzymes in mice. 2. In rats, ABT inhibits gastric emptying, to investigate this potential limitation in mice we examined the effect of ABT administration on the oral absorption of NVS-CRF38. Two hour prior oral treatment with 100 mg/kg ABT inhibited the oral absorption of NVS-CRF38, Tmax was 4 hours for ABT-treated mice compared to 0.5 hours in the control group. 3. A marked inhibition of hepatic P450 activity was observed in mice fed with ABT containing food pellets for 1 month. P450 activity, as measured by the oral clearance of antipyrine, was inhibited on day 3 (88% of control), week 2 (83% of control) and week 4 (80% of control). 4. Tmax values for antipyrine were comparable between ABT-treated mice and the control group, alleviating concerns about impaired gastric function. 5. Inclusion of ABT in food provides a minimally invasive and convenient approach to achieve longer term inhibition of P450 activity in mice. This model has the potential to enable pharmacological proof-of-concept studies for research compounds which are extensively metabolised by P450 enzymes.


Subject(s)
Cytochrome P-450 Enzyme Inhibitors/pharmacology , Cytochrome P-450 Enzyme System/metabolism , Triazoles/pharmacology , Administration, Oral , Animals , Mice , Oxazoles/metabolism , Pyrazoles/metabolism
5.
Clin Pharmacol Ther ; 102(6): 908-911, 2017 Dec.
Article in English | MEDLINE | ID: mdl-28944961

ABSTRACT

Drug development should extract maximum information from experiments with minimized exposure of patients or experimental animals to invasive procedures and potentially harmful effects with minimized investment of time and money. Herein, two aspects of study design are explored illustrating how information can be extracted more efficiently by investigating a range of exposures within each individual by either following responses as drug concentrations decline or by within-individual dose escalation, rather than relying on steady-state cross-sectional analyses.


Subject(s)
Computer Simulation , Models, Statistical , Research Design , Animals , Clinical Trials, Phase II as Topic , Humans
6.
J Allergy Clin Immunol ; 138(4): 1051-1059, 2016 10.
Article in English | MEDLINE | ID: mdl-27185571

ABSTRACT

BACKGROUND: Omalizumab is an established anti-IgE therapy for the treatment of allergic diseases that prevents IgE from binding to its receptor. QGE031 is an investigational anti-IgE antibody that binds IgE with higher affinity than omalizumab. OBJECTIVE: This study compared the effects of QGE031 with those of omalizumab on clinical efficacy, IgE levels, and FcεRI expression in a clinical model of allergic asthma. METHODS: Thirty-seven patients with mild allergic asthma were randomized to subcutaneous omalizumab, placebo, or QGE031 at 24, 72, or 240 mg every 2 weeks for 10 weeks in a double-blind, parallel-group multicenter study. Inhaled allergen challenges and skin tests were conducted before dosing and at weeks 6, 12, and 18, and blood was collected until 24 weeks after the first dose. RESULTS: QGE031 elicited a concentration- and time-dependent change in the provocative concentration of allergen causing a 15% decrease in FEV1 (allergen PC15) that was maximal and approximately 3-fold greater than that of omalizumab (P = .10) and 16-fold greater than that of placebo (P = .0001) at week 12 in the 240-mg cohort. Skin responses reached 85% suppression at week 12 in the 240-mg cohort and were maximal at week 18. The top doses of QGE031 consistently suppressed skin test responses among subjects but had a variable effect on allergen PC15 (2-fold to 500-fold change). QGE031 was well tolerated. CONCLUSION: QGE031 has greater efficacy than omalizumab on inhaled and skin allergen responses in patients with mild allergic asthma. These data support the clinical development of QGE031 as a treatment of asthma.


Subject(s)
Allergens/immunology , Antibodies, Anti-Idiotypic/administration & dosage , Antibodies, Monoclonal, Humanized/administration & dosage , Asthma/drug therapy , Hypersensitivity/prevention & control , Omalizumab/administration & dosage , Adolescent , Adult , Aged , Antibodies, Monoclonal, Humanized/pharmacokinetics , Asthma/complications , Asthma/immunology , Asthma/prevention & control , Dose-Response Relationship, Drug , Female , Humans , Hypersensitivity/complications , Immunoglobulin E/blood , Male , Middle Aged , Models, Theoretical , Omalizumab/pharmacokinetics , Time Factors , Treatment Outcome
7.
Drug Metab Pharmacokinet ; 31(3): 173-84, 2016 Jun.
Article in English | MEDLINE | ID: mdl-27238573

ABSTRACT

A three-part license expansion for omalizumab (Xolair(®)), humanized anti-IgE antibody, was recently made in Japan for paediatric use, additional higher doses and revised dosing frequency in allergic asthma. The dosing level and frequency of omalizumab are guided by a dosing table based on the total serum IgE and bodyweight. Nonlinear mixed-effect pharmacokinetic (PK) and pharmacodynamic (PD) modeling and simulation techniques described the binding between omalizumab and its target IgE. The population PKPD analysis was conducted using data from the nine studies included originally in the European application of dosing table expansion together with three Japanese clinical studies to assess the influence of the ethnicity. Statistically significant differences between the ethnic groups were detected. These were small, within or close to bioequivalence criteria. The model described the primary pharmacology in Caucasian and Japanese patients, both adult and paediatric, with simulations showing that the interplay between the clearance, volume and binding affinity parameters was such that there was no clinical impact of the Japanese ethnic differences on either drug PK or free IgE suppression and hence the required posology.


Subject(s)
Anti-Asthmatic Agents/administration & dosage , Omalizumab/administration & dosage , Adolescent , Adult , Aged , Anti-Asthmatic Agents/pharmacokinetics , Anti-Asthmatic Agents/pharmacology , Asian People , Body Weight , Child , Child, Preschool , Drug Administration Schedule , Humans , Immunoglobulin E/blood , Japan , Middle Aged , Models, Biological , Omalizumab/pharmacokinetics , Omalizumab/pharmacology , White People , Young Adult
8.
Regul Toxicol Pharmacol ; 71(1): 68-77, 2015 Feb.
Article in English | MEDLINE | ID: mdl-25497995

ABSTRACT

The dosing level and frequency of omalizumab are guided by a dosing table based on total serum immunoglobulin E (IgE) and bodyweight. Using a validated, mathematical simulation model (based on concentration data from 8 studies), we evaluated the impact of a revised omalizumab dosing table (every 4 weeks dosing regimen) on the pharmacokinetic and pharmacodynamic profiles of free and total IgE. Safety analysis, in patients with high levels of exposure to omalizumab, was done using data from the clinical and post-marketing databases. The model accurately predicted observed omalizumab, free and total IgE concentrations. After reaching steady-state, the average increase in exposure was 10%, even for patients with the highest concentrations at the upper 97.5th percentile. Free IgE suppression slightly increased in the initial phase, and slightly reduced at the trough of the dosing cycle, but average suppression remained similar for both regimens. The safety profile of omalizumab was similar for patients receiving higher or lower doses. Thus, doubling the dose of omalizumab, in a subset of patients receiving 225-300 mg of omalizumab (every 2 weeks dosing regimen) can efficiently suppress free IgE without compromising safety or efficacy.


Subject(s)
Anti-Asthmatic Agents/administration & dosage , Antibodies, Anti-Idiotypic/administration & dosage , Antibodies, Monoclonal, Humanized/administration & dosage , Models, Biological , Adolescent , Adult , Aged , Anti-Asthmatic Agents/blood , Anti-Asthmatic Agents/pharmacokinetics , Anti-Asthmatic Agents/pharmacology , Antibodies, Anti-Idiotypic/blood , Antibodies, Anti-Idiotypic/pharmacology , Antibodies, Monoclonal, Humanized/blood , Antibodies, Monoclonal, Humanized/pharmacokinetics , Antibodies, Monoclonal, Humanized/pharmacology , Asthma/blood , Asthma/drug therapy , Body Weight , Child , Double-Blind Method , Drug Administration Schedule , Humans , Immunoglobulin E/blood , Middle Aged , Omalizumab , Young Adult
9.
J Allergy Clin Immunol Pract ; 2(5): 525-36.e1, 2014.
Article in English | MEDLINE | ID: mdl-25213045

ABSTRACT

IgE is central to the pathophysiology of allergic asthma. Omalizumab, a humanized anti-IgE mAb, specifically binds free IgE and interrupts the allergic cascade by preventing binding of IgE with its high-affinity FcεRI receptors on mast cells, antigen-presenting cells, and other inflammatory cells. The clinical efficacy of omalizumab has been well documented in a number of clinical trials that involve adults, adolescents, and children with moderate-to-severe and severe allergic asthma. In these studies, omalizumab reduced exacerbations, asthma symptoms, inhaled corticosteroid and rescue medication use, and improved quality of life relative to placebo or best standard of care. Similar benefits have been reported in observational studies in "real-world" populations of patients. Results from recent pooled data from randomized clinical trials and from a large prospective cohort study provide reassurance about the long-term safety of omalizumab. Omalizumab dosing is individualized according to body weight and serum-IgE level, and recent adjustments to the dosing algorithm in Europe have enabled more patients to be eligible for treatment. Ongoing and future research is investigating the optimal duration of therapy, accurate predictors of response to treatment, and efficacy in nonatopic asthma as well as other IgE-mediated conditions.


Subject(s)
Anti-Allergic Agents/therapeutic use , Anti-Asthmatic Agents/therapeutic use , Antibodies, Anti-Idiotypic/therapeutic use , Antibodies, Monoclonal, Humanized/therapeutic use , Asthma/drug therapy , Anti-Allergic Agents/adverse effects , Anti-Allergic Agents/pharmacology , Anti-Asthmatic Agents/adverse effects , Anti-Asthmatic Agents/pharmacology , Antibodies, Anti-Idiotypic/adverse effects , Antibodies, Anti-Idiotypic/pharmacology , Antibodies, Monoclonal, Humanized/adverse effects , Antibodies, Monoclonal, Humanized/pharmacology , Asthma/immunology , Humans , Immunoglobulin E/immunology , Omalizumab
10.
AAPS J ; 16(4): 810-42, 2014 Jul.
Article in English | MEDLINE | ID: mdl-24871341

ABSTRACT

Monoclonal antibodies (mAbs) exhibit biexponential profiles in plasma that are commonly described with a standard two-compartment model with elimination from the central compartment. These models adequately describe mAb plasma PK. However, these models ignore elimination from the peripheral compartment. This may lead to underestimation of the volume of distribution of the peripheral compartment and thus over-predicts concentration in the peripheral compartment. We developed a simple and physiologically relevant model that incorporates information on binding and dissociation rates between mAb and FcRn receptor, mAb uptake, reflection, and catabolic degradation. We employed a previously published PBPK model and, with assumptions regarding rates of processes controlling mAb disposition, reduced the complex PBPK model to a simpler circular model with central, peripheral, and lymph compartments specifying elimination from both central and peripheral. We successfully applied the model to describe the PK of an investigational mAb. Our model presents an improvement over standard two-compartmental models in predicting whole-body average tissue concentrations while adequately describing plasma PK with minimal complexity and physiologically more meaningful parameters.


Subject(s)
Antibodies, Monoclonal/pharmacokinetics , Algorithms , Blood Vessels/metabolism , Endosomes/metabolism , Humans , Liver/metabolism , Lung/metabolism , Models, Biological , Models, Statistical
11.
Reprod Biomed Online ; 29(1): 80-7, 2014 Jul.
Article in English | MEDLINE | ID: mdl-24813755

ABSTRACT

Thrombophilia and impaired placental vasculature are a major cause of adverse pregnancy outcome. In 2007, a new hereditary factor for obstetric complications and recurrent pregnancy loss (RPL) was identified as a sequence variation in the core promoter of the annexin A5 gene, ANXA5, called the M2 haplotype. M2 carriership has been demonstrated in couples with recurrent miscarriage and its origin is embryonic rather than specifically maternal, confirmed by subsequent papers. The M2 haplotype is the first report of a hereditary factor related to pregnancy pathology caused by embryonic-induced anticoagulation. It has been demonstrated that couples with RPL had equal and significantly increased M2 carriership and that maternal and paternal carriership confers equal risk. Given its importance for patients with RPL, and potentially implantation failure, this study assessed the incidence of carrier status for the M2 ANXA5 haplotype in both the male and female of couples attending five CARE IVF centres. In 314 patients (157 couples), 44% of couples (one or both partners), 24% of females, 26% of males and 37% of couples with unexplained infertility were M2 carriers. This high incidence has provoked further urgent studies on specific patient populations and on the value of post embryo-transfer therapy.


Subject(s)
Abortion, Habitual/genetics , Annexin A5/genetics , Heterozygote , Abortion, Habitual/epidemiology , Adult , Female , Fertilization in Vitro , Genetic Carrier Screening , Haplotypes , Humans , Male , Middle Aged , Promoter Regions, Genetic , Thrombophilia/epidemiology , Thrombophilia/genetics
12.
Clin Pharmacokinet ; 51(6): e1-18, 2012 Jun 01.
Article in English | MEDLINE | ID: mdl-22550964

ABSTRACT

Canakinumab is a high-affinity human monoclonal anti-interleukin-1ß (IL-1ß) antibody of the IgG1/κ isotype designed to bind and neutralize the activity of human IL-1ß, a pro-inflammatory cytokine. Canakinumab is currently being investigated on the premise that it would exert anti-inflammatory effects on a broad spectrum of diseases, driven by IL-1ß. This paper focuses on the analysis of the pharmacokinetic and pharmacodynamic data from the canakinumab clinical development programme, describing results from the recently approved indication for the treatment of cryopyrin-associated periodic syndromes (CAPS) under the trade name ILARIS®, as well as diseases such as rheumatoid arthritis, asthma and psoriasis. Canakinumab displays pharmacokinetic properties typical of an IgG1 antibody. In a CAPS patient weighing 70 kg, slow serum clearance (0.174 L/day) was observed with a low total volume of distribution at steady state (6.0 L), resulting in a long elimination half-life of 26 days. The subcutaneous absolute bioavailability was high (70%). Canakinumab displays linear pharmacokinetics, with a dose-proportional increase in exposure and no evidence of accelerated clearance or time-dependent changes in pharmacokinetics following repeated administration was observed. The pharmacokinetics of canakinumab in various diseases (e.g. CAPS, rheumatoid arthritis, psoriasis or asthma) are comparable to those in healthy individuals. No sex- or age-related pharmacokinetic differences were observed after correction for body weight. An increase in total IL-1ß was observed in both healthy subjects and all patient populations following canakinumab dosing, reflecting the ability of canakinumab to bind circulating IL-1ß. The kinetics of total IL-1ß along with the pharmacokinetics of canakinumab were characterized by a population-based pharmacokinetic-binding model, where the apparent in vivo dissociation constant, signifying binding affinity of canakinumab to circulating IL-1ß, was estimated at 1.07 ± 0.173 nmol/L in CAPS patients. During development of canakinumab a cell line change was introduced. Pharmacokinetic characterization was performed in both animals and humans to assure that this manufacturing change did not affect the pharmacokinetic/pharmacodynamic properties of canakinumab.


Subject(s)
Antibodies, Monoclonal/pharmacology , Antibodies, Monoclonal/pharmacokinetics , Cryopyrin-Associated Periodic Syndromes/drug therapy , Interleukin-1beta/antagonists & inhibitors , Interleukin-1beta/immunology , Animals , Antibodies, Monoclonal/adverse effects , Antibodies, Monoclonal/therapeutic use , Antibodies, Monoclonal, Humanized , Clinical Trials as Topic , Humans , Interleukin-1beta/blood
13.
J Clin Pharmacol ; 52(11): 1624-44, 2012 Nov.
Article in English | MEDLINE | ID: mdl-22162538

ABSTRACT

The aim of this study was to develop an integrated pharmacokinetic and pharmacodynamic (PK/PD) model and assess the comparability between epoetin alfa HEXAL/Binocrit (HX575) and a comparator epoetin alfa by a model-based approach. PK/PD data-including serum drug concentrations, reticulocyte counts, red blood cells, and hemoglobin levels-were obtained from 2 clinical studies. In sum, 149 healthy men received multiple intravenous or subcutaneous doses of HX575 (100 IU/kg) and the comparator 3 times a week for 4 weeks. A population model based on pharmacodynamics-mediated drug disposition and cell maturation processes was used to characterize the PK/PD data for the 2 drugs. Simulations showed that due to target amount changes, total clearance may increase up to 2.4-fold as compared with the baseline. Further simulations suggested that once-weekly and thrice-weekly subcutaneous dosing regimens would result in similar efficacy. The findings from the model-based analysis were consistent with previous results using the standard noncompartmental approach demonstrating PK/PD comparability between HX575 and comparator. However, due to complexity of the PK/PD model, control of random effects was not straightforward. Whereas population PK/PD model-based analyses are suited for studying complex biological systems, such models have their limitations (statistical), and their comparability results should be interpreted carefully.


Subject(s)
Erythropoietin/pharmacokinetics , Hematinics/pharmacokinetics , Models, Biological , Administration, Intravenous , Area Under Curve , Epoetin Alfa , Erythrocyte Count , Erythropoietin/administration & dosage , Erythropoietin/blood , Hematinics/administration & dosage , Hematinics/blood , Hemoglobins/analysis , Humans , Injections, Subcutaneous , Male , Monte Carlo Method , Recombinant Proteins/administration & dosage , Recombinant Proteins/blood , Recombinant Proteins/pharmacokinetics , Therapeutic Equivalency
14.
J Environ Manage ; 95(1): 56-65, 2012 Mar.
Article in English | MEDLINE | ID: mdl-22115511

ABSTRACT

It is commonly put forward that effective uptake of research in policy or practice must be built upon a foundation of active knowledge exchange and stakeholder engagement during the research. However, what is often lacking is a systematic appreciation of the specific practices of knowledge exchange and their relative merits. The paper reports on a 2009 survey of 21 research projects within the UK Research Councils' Rural Economy and Land Use Programme regarding the involvement and perceived impact of over a thousand stakeholders in the research. The survey reveals that most stakeholders were involved as research subjects or as event participants. Large numbers were also engaged in the research process itself, including involvement in shaping the direction of research. Stakeholder engagement is perceived as bringing significant benefits to the process of knowledge production. A close relationship is found between mechanisms and approaches to knowledge exchange and the spread of benefits for researchers and stakeholders. Mutual benefits are gained from exchange of staff or where stakeholders are members of research advisory groups. Different stakeholder sectors are also associated with different patterns of engagement, which lead to contrasting impact patterns. Any efforts to alter knowledge exchange processes and outcomes must overcome these differing engagement tendencies. Overall, much greater attention should be given to early processes of knowledge exchange and stakeholder engagement within the lifetime of research projects.


Subject(s)
Communication , Environment , Research , Rural Population , United Kingdom
15.
Philos Trans R Soc Lond B Biol Sci ; 366(1573): 1933-42, 2011 Jul 12.
Article in English | MEDLINE | ID: mdl-21624914

ABSTRACT

Animal and plant diseases pose a serious and continuing threat to food security, food safety, national economies, biodiversity and the rural environment. New challenges, including climate change, regulatory developments, changes in the geographical concentration and size of livestock holdings, and increasing trade make this an appropriate time to assess the state of knowledge about the impact that diseases have and the ways in which they are managed and controlled. In this paper, the case is explored for an interdisciplinary approach to studying the management of infectious animal and plant diseases. Reframing the key issues through incorporating both social and natural science research can provide a holistic understanding of disease and increase the policy relevance and impact of research. Finally, in setting out the papers in this Theme Issue, a picture of current and future animal and plant disease threats is presented.


Subject(s)
Communicable Disease Control/methods , Communicable Diseases/veterinary , Interdisciplinary Communication , Plant Diseases/prevention & control , Agriculture/economics , Animals , Climate Change , Food Safety , Food Supply , Global Health , Humans , Internationality
16.
Philos Trans R Soc Lond B Biol Sci ; 366(1573): 1955-65, 2011 Jul 12.
Article in English | MEDLINE | ID: mdl-21624916

ABSTRACT

This paper analyses how the changing governance of animal health has impacted upon veterinary expertise and its role in providing public health benefits. It argues that the social sciences can play an important role in understanding the nature of these changes, but also that their ideas and methods are, in part, responsible for them. The paper begins by examining how veterinary expertise came to be crucial to the regulation of the food chain in the twentieth century. The relationship between the veterinary profession and the state proved mutually beneficial, allowing the state to address the problems of animal health, and the veterinary profession to become identified as central to public health and food supply. However, this relationship has been gradually eroded by the application of neoliberal management techniques to the governance of animal health. This paper traces the impact of these techniques that have caused widespread unease within and beyond the veterinary profession about the consequences for its role in maintaining the public good of animal health. In conclusion, this paper suggests that the development of the social sciences in relation to animal health could contribute more helpfully to further changes in veterinary expertise.


Subject(s)
Animal Diseases/prevention & control , Veterinary Medicine/standards , Agriculture/economics , Animals , Food Supply , Legislation, Veterinary
17.
Br J Clin Pharmacol ; 72(2): 306-20, 2011 Aug.
Article in English | MEDLINE | ID: mdl-21392073

ABSTRACT

WHAT IS ALREADY KNOWN ABOUT THIS SUBJECT: Omalizumab is a humanized anti-IgE monoclonal antibody that binds and captures circulating IgE, preventing interaction with receptors on mast cells and basophils, thereby interrupting the allergic cascade. It has a well-characterized efficacy and safety profile in patients with asthma. While omalizumab is known to reduce serum free IgE concentrations, effects on total IgE and IgE production are less well characterized. WHAT THIS STUDY ADDS: (i) Confirmation of prior hypotheses that IgE production can decrease with time when patients are given anti-IgE therapy; (ii) guidance on a biomarker, total IgE, which can be used to ascertain whether individual patients experience a change in their IgE production; and (iii) a way to assess whether patients' IgE production has been sufficiently down-regulated such that they may consider stopping anti-IgE therapy. AIM: To determine whether excessive IgE production by patients with atopic allergic asthma decreases with omalizumab therapy. METHODS: Omalizumab, free and total IgE data were obtained from an epidemiological study and six randomized, double-blind, placebo-controlled trials in patients with allergic asthma. The binding between omalizumab and IgE together with the production and elimination of IgE were modelled as previously, except that, in order to explain why total IgE was decreasing over a period of 5 years, the expression of IgE was allowed to change. RESULTS: The prior constant IgE production model failed to converge on the data once long-term observations were included, whereas models allowing IgE production to decrease fitted. A feedback model indicated that, on average, IgE production decreased by 54% per year. This model was further developed with covariate searches indicating clinically small but statistically significant effects of age, gender, body mass index and race on some parameters. Model predictions were checked internally and externally against 3-5 year data from paediatric and adult atopic asthmatic patients and externally against extensive total IgE data from a long-duration (>1 year) phase 1 study which was not used in the model building. CONCLUSIONS: A pharmacokinetic-pharmacodynamic model incorporating omalizumab-IgE binding and feedback for control of IgE production indicates that omalizumab reduces production of IgE. This raises the possibility that indefinite treatment may not be required, only for perhaps a few years. After the initial accumulation, total IgE should provide a means to monitor IgE production and guide individual treatment decisions.


Subject(s)
Anti-Asthmatic Agents/pharmacokinetics , Antibodies, Monoclonal, Humanized/pharmacokinetics , Asthma/immunology , Biomarkers/blood , Immunoglobulin E/blood , Immunoglobulin E/metabolism , Adolescent , Adult , Aged , Anti-Asthmatic Agents/pharmacology , Antibodies, Anti-Idiotypic/pharmacology , Antibodies, Monoclonal, Humanized/pharmacology , Basophils , Child , Child, Preschool , Female , Humans , Male , Mast Cells , Middle Aged , Models, Theoretical , Omalizumab , Randomized Controlled Trials as Topic , Young Adult
18.
AAPS J ; 13(2): 169-78, 2011 Jun.
Article in English | MEDLINE | ID: mdl-21336535

ABSTRACT

In this paper, two applications of mechanism-based modeling are presented with their utility from candidate selection to first-in-human dosage selection. The first example is for a monoclonal antibody against a cytomegalovirus glycoprotein complex, which involves an antibody binding model and a viral load model. The model was used as part of a feasibility analysis prior to antibody generation, setting the specifications for the affinity needed to achieve a desired level of clinical efficacy. The second example is a pharmacokinetic-pharmacodynamic model based on a single-dose pharmacology study in cynomolgus monkey using data on pharmacokinetics, receptor occupancy, and the dynamics of target cell depletion and recovery. The model was used to estimate the MABEL, here defined as the minimum acceptable biological effect level against which a dose is selected for a first-in-human study. From these applications, we demonstrate that mechanism-based PK/PD binding models are useful for predicting human response to biologics compounds. Especially, such models have the ability to integrate preclinical and clinical, in vitro and in vivo information and facilitate rational decision making during various stages of drug discovery and translational research.


Subject(s)
Drug Design , Immunologic Factors/pharmacology , Models, Biological , Animals , Antibodies, Monoclonal/administration & dosage , Antibodies, Monoclonal/pharmacokinetics , Antibodies, Monoclonal/pharmacology , Cytomegalovirus/immunology , Dose-Response Relationship, Drug , Drug Delivery Systems , Feasibility Studies , Glycoproteins/immunology , Humans , Immunologic Factors/administration & dosage , Immunologic Factors/pharmacokinetics , Macaca fascicularis , Species Specificity , Translational Research, Biomedical/methods
19.
Public Adm ; 88(2): 287-95, 2010.
Article in English | MEDLINE | ID: mdl-20827849

ABSTRACT

In response to wide-ranging criticism of agricultural policy, especially within Western industrialized countries, new frameworks of justification are emerging and new hybrid policy fields have been established to tackle some of the 'externalities' of agricultural support. However, institutional frameworks are proving slower to change, partly because this would require coordinated action across different levels of governance. Nevertheless, previously marginalized environmental concerns have successfully gained entrance to agricultural policy networks, while the intersection of trade liberalization and rural diversification have undermined the dominance of the productivist mindset in government. This gives rise to a plurality of policy actors and actions which defy the conventional categories of analysis of agricultural policy, calling for changing frameworks on the polity of agriculture too.


Subject(s)
Agriculture , European Union , Public Health , Public Policy , Social Change , Agriculture/economics , Agriculture/education , Agriculture/history , Agriculture/legislation & jurisprudence , Commerce/economics , Commerce/education , Commerce/history , Commerce/legislation & jurisprudence , Conservation of Natural Resources/economics , Conservation of Natural Resources/history , Conservation of Natural Resources/legislation & jurisprudence , European Union/economics , European Union/history , Government Programs/economics , Government Programs/education , Government Programs/history , Government Programs/legislation & jurisprudence , History, 20th Century , History, 21st Century , Public Health/economics , Public Health/education , Public Health/history , Public Health/legislation & jurisprudence , Public Policy/economics , Public Policy/history , Public Policy/legislation & jurisprudence , Social Change/history , Social Welfare/economics , Social Welfare/ethnology , Social Welfare/history , Social Welfare/legislation & jurisprudence , Social Welfare/psychology
20.
Public Adm ; 88(2): 331-45, 2010.
Article in English | MEDLINE | ID: mdl-20726153

ABSTRACT

For the past decade, the policy community/issue network typology of pressure group interaction has been used to explain policy outcomes and the policy-making process. To re-examine the validity of this typology, the paper focuses on the UK government's response to the 2001 Foot and Mouth Disease (FMD) crisis, and in particular the decision to pursue contiguous culling rather than vaccination to overcome the epidemic. Rather than illustrating the emergence of an issue network in agricultural policy, the decision-making process of the FMD outbreak demonstrates continuity with prior crises. In addition, the politicization of scientific expertise is identified as an emerging trend in crisis management. Policy framing is used to explain the impetus behind the contiguous cull decision, concluding that the legacy of previous policy choices conditioned the crisis response to a far greater degree than contemporaneous pressure group action.


Subject(s)
Agriculture , Foot-and-Mouth Disease , Government Regulation , Preventive Health Services , Public Health , Agriculture/economics , Agriculture/education , Agriculture/history , Agriculture/legislation & jurisprudence , Animals , Disease Outbreaks/economics , Disease Outbreaks/history , Disease Outbreaks/legislation & jurisprudence , Food Supply/economics , Food Supply/history , Food Supply/legislation & jurisprudence , Foot-and-Mouth Disease/economics , Foot-and-Mouth Disease/history , Government Regulation/history , History, 21st Century , Humans , Population Groups/education , Population Groups/ethnology , Population Groups/history , Population Groups/legislation & jurisprudence , Population Groups/psychology , Preventive Health Services/economics , Preventive Health Services/history , Preventive Health Services/legislation & jurisprudence , Public Health/economics , Public Health/education , Public Health/history , Public Health/legislation & jurisprudence , Public Opinion/history , United Kingdom/ethnology
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