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Ozodiegwu ID, Ambrose M, Galatas B, Runge M, Nandi A, Okuneye K, Dhanoa NP, Maikore I, Uhomoibhi P, Bever C, Noor A, Gerardin J. Application of mathematical modelling to inform national malaria intervention planning in Nigeria. Malar J 2023; 22:137. [PMID: 37101146 PMCID: PMC10130303 DOI: 10.1186/s12936-023-04563-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2022] [Accepted: 04/15/2023] [Indexed: 04/28/2023] Open
Abstract
BACKGROUND For their 2021-2025 National Malaria Strategic Plan (NMSP), Nigeria's National Malaria Elimination Programme (NMEP), in partnership with the World Health Organization (WHO), developed a targeted approach to intervention deployment at the local government area (LGA) level as part of the High Burden to High Impact response. Mathematical models of malaria transmission were used to predict the impact of proposed intervention strategies on malaria burden. METHODS An agent-based model of Plasmodium falciparum transmission was used to simulate malaria morbidity and mortality in Nigeria's 774 LGAs under four possible intervention strategies from 2020 to 2030. The scenarios represented the previously implemented plan (business-as-usual), the NMSP at an 80% or higher coverage level and two prioritized plans according to the resources available to Nigeria. LGAs were clustered into 22 epidemiological archetypes using monthly rainfall, temperature suitability index, vector abundance, pre-2010 parasite prevalence, and pre-2010 vector control coverage. Routine incidence data were used to parameterize seasonality in each archetype. Each LGA's baseline malaria transmission intensity was calibrated to parasite prevalence in children under the age of five years measured in the 2010 Malaria Indicator Survey (MIS). Intervention coverage in the 2010-2019 period was obtained from the Demographic and Health Survey, MIS, the NMEP, and post-campaign surveys. RESULTS Pursuing a business-as-usual strategy was projected to result in a 5% and 9% increase in malaria incidence in 2025 and 2030 compared with 2020, while deaths were projected to remain unchanged by 2030. The greatest intervention impact was associated with the NMSP scenario with 80% or greater coverage of standard interventions coupled with intermittent preventive treatment in infants and extension of seasonal malaria chemoprevention (SMC) to 404 LGAs, compared to 80 LGAs in 2019. The budget-prioritized scenario with SMC expansion to 310 LGAs, high bed net coverage with new formulations, and increase in effective case management rate at the same pace as historical levels was adopted as an adequate alternative for the resources available. CONCLUSIONS Dynamical models can be applied for relative assessment of the impact of intervention scenarios but improved subnational data collection systems are required to allow increased confidence in predictions at sub-national level.
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Affiliation(s)
- Ifeoma D Ozodiegwu
- Department of Preventive Medicine and Institute for Global Health, Northwestern University, Chicago, IL, USA.
| | | | - Beatriz Galatas
- Global Malaria Programme, World Health Organization, Geneva, Switzerland
| | - Manuela Runge
- Department of Preventive Medicine and Institute for Global Health, Northwestern University, Chicago, IL, USA
| | - Aadrita Nandi
- Department of Preventive Medicine and Institute for Global Health, Northwestern University, Chicago, IL, USA
| | - Kamaldeen Okuneye
- Department of Preventive Medicine and Institute for Global Health, Northwestern University, Chicago, IL, USA
| | - Neena Parveen Dhanoa
- Weinberg College of Arts and Sciences, Northwestern University, Evanston, IL, USA
| | - Ibrahim Maikore
- Global Malaria Programme, World Health Organization, Geneva, Switzerland
| | | | | | - Abdisalan Noor
- Global Malaria Programme, World Health Organization, Geneva, Switzerland
| | - Jaline Gerardin
- Department of Preventive Medicine and Institute for Global Health, Northwestern University, Chicago, IL, USA
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White NJ. The assessment of antimalarial drug efficacy in vivo. Trends Parasitol 2022; 38:660-672. [PMID: 35680541 PMCID: PMC7613059 DOI: 10.1016/j.pt.2022.05.008] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2022] [Revised: 05/13/2022] [Accepted: 05/16/2022] [Indexed: 11/19/2022]
Abstract
Currently recommended methods of assessing uncomplicated falciparum malaria treatment work less well in high transmission than in low transmission settings. There is also uncertainty how to assess intermittent preventive therapies and seasonal malaria chemoprevention, and P. vivax radical cure. A “pharmacometric antimalarial resistance monitoring (PARM)” approach is proposed for slowly eliminated antimalarial drugs in areas of high transmission. In PARM antimalarial drug concentrations at recurrent parasitaemia are measured to identify outliers (i.e. recurrent parasitaemias in the presence of normally suppressive drug concentrations), and to characterise changes over time. PARM requires characterization of pharmacometric profiles but should be simpler and more sensitive than current methodologies. PARM does not require parasite genotyping, and can be applied to the assessment of both prevention and treatment.
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Affiliation(s)
- Nicholas J White
- Mahidol-Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand; Centre for Tropical Medicine and Global Health, Nuffield Department of Medicine, Oxford University, Oxford, UK.
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A Whole-Body Physiologically Based Pharmacokinetic Model Characterizing Interplay of OCTs and MATEs in Intestine, Liver and Kidney to Predict Drug-Drug Interactions of Metformin with Perpetrators. Pharmaceutics 2021; 13:pharmaceutics13050698. [PMID: 34064886 PMCID: PMC8151202 DOI: 10.3390/pharmaceutics13050698] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2021] [Revised: 04/30/2021] [Accepted: 05/07/2021] [Indexed: 12/27/2022] Open
Abstract
Transmembrane transport of metformin is highly controlled by transporters including organic cation transporters (OCTs), plasma membrane monoamine transporter (PMAT), and multidrug/toxin extrusions (MATEs). Hepatic OCT1, intestinal OCT3, renal OCT2 on tubule basolateral membrane, and MATE1/2-K on tubule apical membrane coordinately work to control metformin disposition. Drug–drug interactions (DDIs) of metformin occur when co-administrated with perpetrators via inhibiting OCTs or MATEs. We aimed to develop a whole-body physiologically based pharmacokinetic (PBPK) model characterizing interplay of OCTs and MATEs in the intestine, liver, and kidney to predict metformin DDIs with cimetidine, pyrimethamine, trimethoprim, ondansetron, rabeprazole, and verapamil. Simulations showed that co-administration of perpetrators increased plasma exposures to metformin, which were consistent with clinic observations. Sensitivity analysis demonstrated that contributions of the tested factors to metformin DDI with cimetidine are gastrointestinal transit rate > inhibition of renal OCT2 ≈ inhibition of renal MATEs > inhibition of intestinal OCT3 > intestinal pH > inhibition of hepatic OCT1. Individual contributions of transporters to metformin disposition are renal OCT2 ≈ renal MATEs > intestinal OCT3 > hepatic OCT1 > intestinal PMAT. In conclusion, DDIs of metformin with perpetrators are attributed to integrated effects of inhibitions of these transporters.
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Sjögren E, Tarning J, Barnes KI, Jonsson EN. A Physiologically-Based Pharmacokinetic Framework for Prediction of Drug Exposure in Malnourished Children. Pharmaceutics 2021; 13:pharmaceutics13020204. [PMID: 33540928 PMCID: PMC7913226 DOI: 10.3390/pharmaceutics13020204] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2020] [Revised: 01/21/2021] [Accepted: 01/28/2021] [Indexed: 02/06/2023] Open
Abstract
Malnutrition in children is a global health problem, particularly in developing countries. The effects of an insufficient supply of nutrients on body composition and physiological functions may have implications for drug disposition and ultimately affect the clinical outcome in this vulnerable population. Physiologically-based pharmacokinetic (PBPK) modeling can be used to predict the effect of malnutrition as it links physiological changes to pharmacokinetic (PK) consequences. However, the absence of detailed information on body composition and the limited availability of controlled clinical trials in malnourished children complicates the establishment and evaluation of a generic PBPK model in this population. In this manuscript we describe the creation of physiologically-based bridge to a malnourished pediatric population, by combining information on (a) the differences in body composition between healthy and malnourished adults and (b) the differences in physiology between healthy adults and children. Model performance was confirmed using clinical reference data. This study presents a physiologically-based translational framework for prediction of drug disposition in malnourished children. The model is readily applicable for dose recommendation strategies to address the urgent medicinal needs of this vulnerable population.
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Affiliation(s)
- Erik Sjögren
- Pharmetheus AB, 752 37 Uppsala, Sweden;
- Correspondence: ; Tel.: +46-737-750-545
| | - Joel Tarning
- Mahidol Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Bangkok 10400, Thailand;
- Centre for Tropical Medicine and Global Health, Nuffield Department of Medicine, University of Oxford, Oxford OX3 7LG, UK
| | - Karen I. Barnes
- Division of Clinical Pharmacology, Department of Medicine, University of Cape Town, Cape Town 7925, South Africa;
- WorldWide Antimalarial Resistance Network (WWARN) Pharmacology Scientific Working Group, University of Cape Town, Cape Town 7925, South Africa
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Karbwang J, Na‐Bangchang K. The Role of Clinical Pharmacology in Chemotherapy of Multidrug‐Resistant
Plasmodium falciparum. J Clin Pharmacol 2020; 60:830-847. [DOI: 10.1002/jcph.1589] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2019] [Accepted: 01/21/2020] [Indexed: 01/02/2023]
Affiliation(s)
- Juntra Karbwang
- Graduate Program in Bioclinical SciencesChulabhorn International College of MedicineThammasat University (Rangsit Campus) Pathumthani Thailand
- Center of Excellence in Pharmacology and Molecular Biology of Malaria and CholangiocarcinomaThammasat University (Rangsit Campus) Pathumthani Thailand
- Drug Discovery and Development Center, Office of Advanced Science and TechnologyThammasat University (Rangsit Campus) Pathumthani Thailand
- Department of Clinical Product developmentNagasaki Institute of Tropical MedicineNagasaki University Nagasaki Japan
| | - Kesara Na‐Bangchang
- Graduate Program in Bioclinical SciencesChulabhorn International College of MedicineThammasat University (Rangsit Campus) Pathumthani Thailand
- Center of Excellence in Pharmacology and Molecular Biology of Malaria and CholangiocarcinomaThammasat University (Rangsit Campus) Pathumthani Thailand
- Drug Discovery and Development Center, Office of Advanced Science and TechnologyThammasat University (Rangsit Campus) Pathumthani Thailand
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Ding J, Coldiron ME, Assao B, Guindo O, Blessborn D, Winterberg M, Grais RF, Koscalova A, Langendorf C, Tarning J. Adherence and Population Pharmacokinetic Properties of Amodiaquine When Used for Seasonal Malaria Chemoprevention in African Children. Clin Pharmacol Ther 2019; 107:1179-1188. [PMID: 31652336 PMCID: PMC7232861 DOI: 10.1002/cpt.1707] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2019] [Accepted: 08/29/2019] [Indexed: 01/23/2023]
Abstract
Poor adherence to seasonal malaria chemoprevention (SMC) might affect the protective effectiveness of SMC. Here, we evaluated the population pharmacokinetic properties of amodiaquine and its active metabolite, desethylamodiaquine, in children receiving SMC under directly observed ideal conditions (n = 136), and the adherence of SMC at an implementation phase in children participating in a case‐control study to evaluate SMC effectiveness (n = 869). Amodiaquine and desethylamodiaquine concentration‐time profiles were described simultaneously by two‐compartment and three‐compartment disposition models, respectively. The developed methodology to evaluate adherence showed a sensitivity of 65–71% when the first dose of SMC was directly observed and 71–73% when no doses were observed in a routine programmatic setting. Adherence simulations and measured desethylamodiaquine concentrations in the case‐control children showed complete adherence (all doses taken) in < 20% of children. This result suggests that more efforts are needed urgently to improve the adherence to SMC among children in this area.
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Affiliation(s)
- Junjie Ding
- Centre for Tropical Medicine and Global Health, Nuffield Department of Clinical Medicine, University of Oxford, Oxford, UK.,The WorldWide Antimalarial Resistance Network, Oxford, UK.,Children's Hospital of Fudan University, Shanghai, China
| | | | | | | | - Daniel Blessborn
- Centre for Tropical Medicine and Global Health, Nuffield Department of Clinical Medicine, University of Oxford, Oxford, UK.,Mahidol-Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand
| | - Markus Winterberg
- Centre for Tropical Medicine and Global Health, Nuffield Department of Clinical Medicine, University of Oxford, Oxford, UK.,Mahidol-Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand
| | | | | | | | - Joel Tarning
- Centre for Tropical Medicine and Global Health, Nuffield Department of Clinical Medicine, University of Oxford, Oxford, UK.,The WorldWide Antimalarial Resistance Network, Oxford, UK.,Mahidol-Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand
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Hecht M, Veigure R, Couchman L, S Barker CI, Standing JF, Takkis K, Evard H, Johnston A, Herodes K, Leito I, Kipper K. Utilization of data below the analytical limit of quantitation in pharmacokinetic analysis and modeling: promoting interdisciplinary debate. Bioanalysis 2018; 10:1229-1248. [PMID: 30033744 DOI: 10.4155/bio-2018-0078] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
Traditionally, bioanalytical laboratories do not report actual concentrations for samples with results below the LOQ (BLQ) in pharmacokinetic studies. BLQ values are outside the method calibration range established during validation and no data are available to support the reliability of these values. However, ignoring BLQ data can contribute to bias and imprecision in model-based pharmacokinetic analyses. From this perspective, routine use of BLQ data would be advantageous. We would like to initiate an interdisciplinary debate on this important topic by summarizing the current concepts and use of BLQ data by regulators, pharmacometricians and bioanalysts. Through introducing the limit of detection and evaluating its variability, BLQ data could be released and utilized appropriately for pharmacokinetic research.
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Affiliation(s)
- Max Hecht
- Chair of Analytical Chemistry, Institute of Chemistry, University of Tartu, 14a Ravila Street, 50411 Tartu, Estonia
- Analytical Services International, St George's University of London, Cranmer Terrace, London, SW17 0RE, UK
| | - Rūta Veigure
- Chair of Analytical Chemistry, Institute of Chemistry, University of Tartu, 14a Ravila Street, 50411 Tartu, Estonia
| | - Lewis Couchman
- Analytical Services International, St George's University of London, Cranmer Terrace, London, SW17 0RE, UK
| | - Charlotte I S Barker
- Paediatric Infectious Diseases Research Group, Institute for Infection & Immunity, St George's University of London, London, SW17 0RE, UK
- Inflammation, Infection & Rheumatology Section, UCL Great Ormond Street Institute of Child Health, London, WC1N 1EH, UK
- Paediatric Infectious Diseases Unit, St George's University Hospitals NHS Foundation Trust, London, SW17 0RE, UK
| | - Joseph F Standing
- Paediatric Infectious Diseases Research Group, Institute for Infection & Immunity, St George's University of London, London, SW17 0RE, UK
- Inflammation, Infection & Rheumatology Section, UCL Great Ormond Street Institute of Child Health, London, WC1N 1EH, UK
| | - Kalev Takkis
- Analytical Services International, St George's University of London, Cranmer Terrace, London, SW17 0RE, UK
| | - Hanno Evard
- Chair of Analytical Chemistry, Institute of Chemistry, University of Tartu, 14a Ravila Street, 50411 Tartu, Estonia
| | - Atholl Johnston
- Analytical Services International, St George's University of London, Cranmer Terrace, London, SW17 0RE, UK
- Clinical Pharmacology, Barts & The London School of Medicine & Dentistry, Queen Mary University of London, London, EC1M 6BQ, UK
| | - Koit Herodes
- Chair of Analytical Chemistry, Institute of Chemistry, University of Tartu, 14a Ravila Street, 50411 Tartu, Estonia
| | - Ivo Leito
- Chair of Analytical Chemistry, Institute of Chemistry, University of Tartu, 14a Ravila Street, 50411 Tartu, Estonia
| | - Karin Kipper
- Chair of Analytical Chemistry, Institute of Chemistry, University of Tartu, 14a Ravila Street, 50411 Tartu, Estonia
- Analytical Services International, St George's University of London, Cranmer Terrace, London, SW17 0RE, UK
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Population Pharmacokinetic Properties of Sulfadoxine and Pyrimethamine: a Pooled Analysis To Inform Optimal Dosing in African Children with Uncomplicated Malaria. Antimicrob Agents Chemother 2018; 62:AAC.01370-17. [PMID: 29463542 PMCID: PMC5923181 DOI: 10.1128/aac.01370-17] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2017] [Accepted: 02/09/2018] [Indexed: 02/07/2023] Open
Abstract
Sulfadoxine-pyrimethamine with amodiaquine is recommended by the World Health Organization as seasonal malaria chemoprevention for children aged 3 to 59 months in the sub-Sahel regions of Africa. Suboptimal dosing in children may lead to treatment failure and increased resistance. Pooled individual patient data from four previously published trials on the pharmacokinetics of sulfadoxine and pyrimethamine in 415 pediatric and 386 adult patients were analyzed using nonlinear mixed-effects modeling to evaluate the current dosing regimen and, if needed, to propose an optimized dosing regimen for children under 5 years of age. The population pharmacokinetics of sulfadoxine and pyrimethamine were both best described by a one-compartment disposition model with first-order absorption and elimination. Body weight, age, and nutritional status (measured as the weight-for-age Z-score) were found to be significant covariates. Allometric scaling with total body weight and the maturation of clearance in children by postgestational age improved the model fit. Underweight-for-age children were found to have 15.3% and 26.7% lower bioavailabilities of sulfadoxine and pyrimethamine, respectively, for each Z-score unit below -2. Under current dosing recommendations, simulation predicted that the median day 7 concentration was below the 25th percentile for a typical adult patient (50 kg) for sulfadoxine for patients in the weight bands of 8 to 9, 19 to 24, 46 to 49, and 74 to 79 kg and for pyrimethamine for patients in the weight bands of 8 to 9, 14 to 24, and 42 to 49 kg. An evidence-based dosing regimen was constructed that would achieve sulfadoxine and pyrimethamine exposures in young children and underweight-for-age young children that were similar to those currently seen in a typical adult.
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Sugiarto SR, Davis TME, Salman S. Pharmacokinetic considerations for use of artemisinin-based combination therapies against falciparum malaria in different ethnic populations. Expert Opin Drug Metab Toxicol 2017; 13:1115-1133. [PMID: 29027504 DOI: 10.1080/17425255.2017.1391212] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
INTRODUCTION Artemisinin-based combination therapy (ACT) is used extensively as first-line treatment for uncomplicated falciparum malaria. There has been no rigorous assessment of the potential for racial/ethnic differences in the pharmacokinetic properties of ACTs that might influence their efficacy. Areas covered: A comprehensive literature search was performed that identified 72 publications in which the geographical origin of the patients could be ascertained and the key pharmacokinetic parameters maximum drug concentration (Cmax), area under the plasma concentration-time curve (AUC) and elimination half-life (t½β) were available for one or more of the five WHO-recommended ACTs (artemether-lumefantrine, artesunate-amodiaquine, artesunate-mefloquine, dihydroartemisinin-piperaquine and artesunate-sulfadoxine-pyrimethamine). Comparisons of each of the three pharmacokinetic parameters of interest were made by drug (artemisinin derivative and long half-life partner), race/ethnicity (African, Asian, Caucasian, Melanesian, South American) and patient categories based on age and pregnancy status. Expert opinion: The review identified no evidence of a clinically significant influence of race/ethnicity on the pharmacokinetic properties of the nine component drugs in the five ACTs currently recommended by WHO for first-line treatment of uncomplicated falciparum malaria. This provides reassurance for health workers in malaria-endemic regions that ACTs can be given in recommended doses with the expectation of adequate blood concentrations regardless of race/ethnicity.
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Affiliation(s)
- Sri Riyati Sugiarto
- a Medical School , University of Western Australia, Fremantle Hospital , Fremantle , Australia
| | - Timothy M E Davis
- a Medical School , University of Western Australia, Fremantle Hospital , Fremantle , Australia
| | - Sam Salman
- a Medical School , University of Western Australia, Fremantle Hospital , Fremantle , Australia
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Patel K, Simpson JA, Batty KT, Zaloumis S, Kirkpatrick CM. Modelling the time course of antimalarial parasite killing: a tour of animal and human models, translation and challenges. Br J Clin Pharmacol 2015; 79:97-107. [PMID: 24251882 PMCID: PMC4294080 DOI: 10.1111/bcp.12288] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2013] [Accepted: 10/31/2013] [Indexed: 01/06/2023] Open
Abstract
Malaria remains a global public health concern and current treatment options are suboptimal in some clinical settings. For effective chemotherapy, antimalarial drug concentrations must be sufficient to remove completely all of the parasites in the infected host. Optimized dosing therefore requires a detailed understanding of the time course of antimalarial response, whilst simultaneously considering the parasite life cycle and host immune elimination. Recently, the World Health Organization (WHO) has recommended the development of mathematical models for understanding better antimalarial drug resistance and management. Other international groups have also suggested that mechanistic pharmacokinetic (PK) and pharmacodynamic (PD) models can support the rationalization of antimalarial dosing strategies. At present, artemisinin-based combination therapy (ACT) is recommended as first line treatment of falciparum malaria for all patient groups. This review summarizes the PK-PD characterization of artemisinin derivatives and other partner drugs from both preclinical studies and human clinical trials. We outline the continuous and discrete time models that have been proposed to describe antimalarial activity on specific stages of the parasite life cycle. The translation of PK-PD predictions from animals to humans is considered, because preclinical studies can provide rich data for detailed mechanism-based modelling. While similar sampling techniques are limited in clinical studies, PK-PD models can be used to optimize the design of experiments to improve estimation of the parameters of interest. Ultimately, we propose that fully developed mechanistic models can simulate and rationalize ACT or other treatment strategies in antimalarial chemotherapy.
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Affiliation(s)
- Kashyap Patel
- Centre for Medicine Use and Safety, Monash UniversityMelbourne, VIC, Australia
| | - Julie A Simpson
- Centre for Molecular, Environmental, Genetic & Analytic Epidemiology, Melbourne School of Population and Global Health, The University of MelbourneMelbourne, VIC, Australia
| | - Kevin T Batty
- School of Pharmacy, Curtin UniversityBentley, WA, Australia
- West Coast InstituteJoondalup, WA, Australia
| | - Sophie Zaloumis
- Centre for Molecular, Environmental, Genetic & Analytic Epidemiology, Melbourne School of Population and Global Health, The University of MelbourneMelbourne, VIC, Australia
| | - Carl M Kirkpatrick
- Centre for Medicine Use and Safety, Monash UniversityMelbourne, VIC, Australia
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Pharmacokinetic and pharmacodynamic considerations in antimalarial dose optimization. Antimicrob Agents Chemother 2013; 57:5792-807. [PMID: 24002099 PMCID: PMC3837842 DOI: 10.1128/aac.00287-13] [Citation(s) in RCA: 72] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023] Open
Abstract
Antimalarial drugs have usually been first deployed in areas of malaria endemicity at doses which were too low, particularly for high-risk groups such as young children and pregnant women. This may accelerate the emergence and spread of resistance, thereby shortening the useful life of the drug, but it is an inevitable consequence of the current imprecise method of dose finding. An alternative approach to dose finding is suggested in which phase 2 studies concentrate initially on pharmacokinetic-pharmacodynamic (PK-PD) characterization and in vivo calibration of in vitro susceptibility information. PD assessment is facilitated in malaria because serial parasite densities are readily assessed by microscopy, and at low densities by quantitative PCR, so that initial therapeutic responses can be quantitated accurately. If the in vivo MIC could be characterized early in phase 2 studies, it would provide a sound basis for the choice of dose in all target populations in subsequent combination treatments. Population PK assessments in phase 2b and phase 3 studies which characterize PK differences between different age groups, clinical disease states, and human populations can then be combined with the PK-PD observations to provide a sound evidence base for dose recommendations in different target groups.
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Pharmacokinetic Profile of Artemisinin Derivatives and Companion Drugs Used in Artemisinin-Based Combination Therapies for the Treatment of Plasmodium falciparum Malaria in Children. Clin Pharmacokinet 2013; 52:153-67. [DOI: 10.1007/s40262-012-0026-5] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023]
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Pharmacokinetic properties and bioequivalence of two sulfadoxine/pyrimethamine fixed-dose combination tablets: a parallel-design study in healthy Chinese male volunteers. Clin Ther 2012; 34:2212-20. [PMID: 23084093 DOI: 10.1016/j.clinthera.2012.10.001] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2012] [Revised: 09/26/2012] [Accepted: 10/01/2012] [Indexed: 11/20/2022]
Abstract
BACKGROUND Sulfadoxine/pyrimethamine fixed-dose combination (FDC) tablet is the long-acting portion of the antimalaria product Artecospe(®), coblister containing artesunate tablets plus sulfadoxine/pyrimethamine FDC tablets. This study was conducted to support the efficacy and tolerability of the sulfadoxine/pyrimethamine FDC tablet in the World Health Organization's (WHO) Prequalification of Medicines Programme, as well as to obtain marketing authorization in China. OBJECTIVE The aim of the present study was to compare the pharmacokinetic profiles between a new generic and the branded reference formulation of sulfadoxine/pyrimethamine FDC tablets, and to assess the bioequivalence of the 2 products in healthy Chinese volunteers. METHODS This single-dose, open-label, randomized, parallel-group study was conducted in healthy Chinese male volunteers who were randomly assigned (1:1) to receive a single 1500/75-mg dose (3 × 500/25-mg tablets) of either the test or reference formulation after a 12-hour overnight fast. Seventeen blood samples were obtained over a 168-hour interval, and plasma concentrations of sulfadoxine and pyrimethamine were determined by 2 separate validated liquid chromatography-isotopic dilution mass spectrometry methods. Pharmacokinetic properties (C(max), AUC(0-72), AUC(0-168), and T(max)) were calculated and analyzed statistically. The 2 formulations were to be considered bioequivalent if 90% CIs for the log-transformed ratios of C(max) and AUC(0-72) were within the predetermined bioequivalence range of 80% to 125%, in accordance with the guidelines of WHO and China's Food and Drug Administration (FDA). Tolerability was evaluated throughout the study by vital signs, physical examinations, clinical laboratory tests, 12-lead ECGs, and subject interviews on adverse events (AEs). RESULTS Forty-six healthy subjects completed the study. The mean values of sulfadoxine C(max) (183.07 and 165.15 mg/L), AUC(0-72) (11,036.52 and 10,536.78 mg/L/h), and AUC(0-168) (22,247.05 and 21,761.02 mg/L/h) were not significantly different between the test and reference formulations, respectively. The same was true for pyrimethamine (0.55 and 0.58 mg/L, 29.85 and 31.44 mg/L/h, and 56.18 and 59.27 mg/L/h, respectively). The 90% CIs for the log-transformed ratios of C(max), AUC(0-72), and AUC(0-168) of both sulfadoxine (105.4%-116.6%, 99.3%-110.6%, and 96.4%-108.1%) and pyrimethamine (88.8%-100.9%, 89.5%-101.0%, and 88.3%-101.6%) were within the acceptance limits for bioequivalence. A total of 7 mild AEs were reported in 7 subjects (15.2%). CONCLUSIONS The findings from this single-dose (1500/75-mg) study suggest that the test and reference formulations of sulfadoxine/pyrimethamine FDC 500/25-mg tablet have similar pharmacokinetic profiles both in terms of rate and extent of absorption. The formulations met WHO's and China's FDA regulatory criteria for bioequivalence in these healthy Chinese volunteers under fasting conditions. Both formulations were generally well-tolerated.
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Crawley J, Sismanidis C, Goodman T, Milligan P. Effect of intermittent preventive treatment for malaria during infancy on serological responses to measles and other vaccines used in the Expanded Programme on Immunization: results from five randomised controlled trials. Lancet 2012; 380:1001-10. [PMID: 22850358 DOI: 10.1016/s0140-6736(12)60775-2] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
BACKGROUND Intermittent preventive treatment for malaria during infancy (IPTi) is the administration of a full therapeutic course of antimalarial drugs to infants living in settings where malaria is endemic, at the time of routine vaccination in the first year of life. We investigated whether IPTi with sulfadoxine-pyrimethamine or other antimalarial drug combinations adversely affected serological responses to vaccines used in the Expanded Programme on Immunization (EPI). METHODS The study was done in a subset of children enrolled in five randomised controlled trials in Navrongo, Ghana; Kilimanjaro, Tanzania; Manhica, Mozambique; Kisumu, Kenya; and Bungoma, Kenya. All infants presenting for the second dose of the diphtheria-tetanus-pertussis vaccination (given at 8-10 weeks of age) were eligible, and analyses included all children who had received measles vaccination (at 9 months of age) and at least one dose of IPTi or placebo. Blood samples were collected before and after vaccination, and antibody titres were measured by plaque reduction neutralisation (measles, yellow fever), microneutralisation (polio serotypes 1 and 3), and ELISA (all other EPI antigens). Laboratory personnel were unaware of the randomisation groups. We compared the proportion of infants in the IPTi and placebo groups who did not attain protective antibody titres after vaccination, using a one-sided significance non-inferiority margin of 5% for measles (the primary endpoint) and 10% for other EPI antigens. FINDINGS Between September, 2000, and May, 2008, 8416 children were enrolled in the five studies. Paired samples from 2368 children from sites where sulfadoxine-pyrimethamine was compared with placebo were analysed for measles antibodies. 464 children with detectable measles antibody in their sample before vaccination were excluded, leaving 1904 individuals (934 placebo and 970 sulfadoxine-pyrimethamine) in the study. IPTi with sulfadoxine-pyrimethamine did not have a clinically significant effect on immune responses to measles vaccine; 61 of 970 (6·3%) children who received IPTi did not develop a protective antibody response after measles vaccination compared with 60 of 934 (6·4%) who received placebo, a difference of -0·14% (95% CI -2·3 to 2·1). When other antimalarial drugs were used for IPTi the results were much the same. Among 2396 children from whom serological response data for other EPI antigens were available, we identified no evidence of an adverse effect of IPTi with sulfadoxine-pyrimethamine or other antimalarial drugs on the proportion achieving protective antibody concentrations. INTERPRETATION IPTi with sulfadoxine-pyrimethamine does not affect serological responses to EPI vaccines. This analysis, therefore, supports the WHO recommendation for coadministration of IPTi with sulfadoxine-pyrimethamine to infants at the time of the second and third doses of DTP and measles vaccination, in areas of sub-Saharan Africa with moderate to high malaria transmission and where malaria parasites are sensitive to these drugs. It also suggests that treatment of clinical malaria at or around the time of vaccination does not compromise vaccine responsiveness. FUNDING Bill & Melinda Gates Foundation.
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Affiliation(s)
- Jane Crawley
- Nuffield Department of Clinical Medicine, University of Oxford, Oxford, UK
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Sibley CH, Price RN. Monitoring antimalarial drug resistance: Applying lessons learned from the past in a fast-moving present. INTERNATIONAL JOURNAL FOR PARASITOLOGY-DRUGS AND DRUG RESISTANCE 2012; 2:126-33. [PMID: 24533274 DOI: 10.1016/j.ijpddr.2012.03.004] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/16/2011] [Revised: 03/25/2012] [Accepted: 03/28/2012] [Indexed: 11/19/2022]
Abstract
The need for robust surveillance of antimalarial drugs is more urgent than it has ever been. In the western region of Cambodia, artemisinin resistance has emerged in Plasmodium falciparum and threatens to undermine the efficacy of highly effective artemisinin combination therapies. Although some manfestations of artemisinin tolerance are unique to this class of drug, many of its properties mirror previous experience in understanding and tracking resistance to other antimalarials. In this review we outline the spectrum of approaches that were developed to understand the evolution and spread of antifolate resistance, highlighting the importance of integrating information from different methodologies towards a better understanding of the underlying biologic processes. We consider how to apply our experience in investigating and attempting to contain antifolate resistance to inform our prospective assessment of novel antimalarial resistance patterns and their subsequent spread.
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Affiliation(s)
- Carol Hopkins Sibley
- WorldWide Antimalarial Resistance Network, Box 355065, University of Washington, Seattle, WA 98195 5065, USA
| | - Ric N Price
- Global Health Division, Menzies School of Health Research and Charles Darwin University, Darwin, Northern Territory, Australia ; Center for Tropical Medicine, Nuffield Department of Clinical Medicine, University of Oxford, United Kingdom
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Gbotosho GO, Happi CT, Lawal O, Sijuade A, Sowunmi A, Oduola A. A high performance liquid chromatographic assay of mefloquine in saliva after a single oral dose in healthy adult Africans. Malar J 2012; 11:59. [PMID: 22369125 PMCID: PMC3311565 DOI: 10.1186/1475-2875-11-59] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2011] [Accepted: 02/27/2012] [Indexed: 11/16/2022] Open
Abstract
Background Mefloquine-artesunate is a formulation of artemisinin based combination therapy (ACT) recommended by the World Health Organization and historically the first ACT used clinically. The use of ACT demands constant monitoring of therapeutic efficacies and drug levels, in order to ensure that optimum drug exposure is achieved and detect reduced susceptibility to these drugs. Quantification of anti-malarial drugs in biological fluids other than blood would provide a more readily applicable method of therapeutic drug monitoring in developing endemic countries. Efforts in this study were devoted to the development of a simple, field applicable, non-invasive method for assay of mefloquine in saliva. Methods A high performance liquid chromatographic method with UV detection at 220 nm for assaying mefloquine in saliva was developed and validated by comparing mefloquine concentrations in saliva and plasma samples from four healthy volunteers who received single oral dose of mefloquine. Verapamil was used as internal standard. Chromatographic separation was achieved using a Hypersil ODS column. Results Extraction recoveries of mefloquine in plasma or saliva were 76-86% or 83-93% respectively. Limit of quantification of mefloquine was 20 ng/ml. Agreement between salivary and plasma mefloquine concentrations was satisfactory (r = 0.88, p < 0.001). Saliva:plasma concentrations ratio was 0.42. Conclusion Disposition of mefloquine in saliva paralleled that in plasma, making salivary quantification of mefloquine potentially useful in therapeutic drug monitoring.
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Affiliation(s)
- Grace O Gbotosho
- Department of Pharmacology and Therapeutics, College of Medicine, University of Ibadan, Ibadan, Nigeria.
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Tekete MM, Toure S, Fredericks A, Beavogui AH, Sangare CPO, Evans A, Smith P, Maiga H, Traore ZI, Doumbo OK, Barnes KI, Djimde AA. Effects of amodiaquine and artesunate on sulphadoxine-pyrimethamine pharmacokinetic parameters in children under five in Mali. Malar J 2011; 10:275. [PMID: 21936885 PMCID: PMC3197573 DOI: 10.1186/1475-2875-10-275] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2011] [Accepted: 09/21/2011] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Sulphadoxine-pyrimethamine, in combination with artesunate or amodiaquine, is recommended for the treatment of uncomplicated malaria and is being evaluated for intermittent preventive treatment. Yet, limited data is available on pharmacokinetic interactions between these drugs. METHODS In a randomized controlled trial, children aged 6-59 months with uncomplicated falciparum malaria, received either one dose of sulphadoxine-pyrimethamine alone (SP), one dose of SP plus three daily doses of amodiaquine (SP+AQ) or one dose of SP plus 3 daily doses of artesunate (SP+AS). Exactly 100 μl of capillary blood was collected onto filter paper before drug administration at day 0 and at days 1, 3, 7, 14, 21 and 28 after drug administration for analysis of sulphadoxine and pyrimethamine pharmacokinetic parameters. RESULTS Fourty, 38 and 31 patients in the SP, SP+AQ and SP+AS arms, respectively were included in this study. The concentrations on day 7 (that are associated with therapeutic efficacy) were similar between the SP, SP+AQ and SP+AS treatment arms for sulphadoxine (median [IQR] 35.25 [27.38-41.70], 34.95 [28.60-40.85] and 33.40 [24.63-44.05] μg/mL) and for pyrimethamine (56.75 [46.40-92.95], 58.75 [43.60-98.60] and 59.60 [42.45-86.63] ng/mL). There were statistically significant differences between the pyrimethamine volumes of distribution (4.65 [3.93-6.40], 4.00 [3.03-5.43] and 5.60 [4.40-7.20] L/kg; p = 0.001) and thus elimination half-life (3.26 [2.74 -3.82], 2.78 [2.24-3.65] and 4.02 [3.05-4.85] days; p < 0.001). This study confirmed the lower SP concentrations previously reported for young children when compared with adult malaria patients. CONCLUSION Despite slight differences in pyrimethamine volumes of distribution and elimination half-life, these data show similar exposure to SP over the critical initial seven days of treatment and support the current use of SP in combination with either AQ or AS for uncomplicated falciparum malaria treatment in young Malian children.
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Affiliation(s)
- Mamadou M Tekete
- Molecular Epidemiology and Drug Resistance Unit, Malaria Research and Training Centre, Department of Epidemiology of Parasitic Diseases, Faculty of Medicine, Pharmacy and Dentistry, University of Bamako, P,O, Box: 1805, Bamako, Mali
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Population pharmacokinetics of artemether, lumefantrine, and their respective metabolites in Papua New Guinean children with uncomplicated malaria. Antimicrob Agents Chemother 2011; 55:5306-13. [PMID: 21876056 DOI: 10.1128/aac.05136-11] [Citation(s) in RCA: 48] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
There are sparse published data relating to the pharmacokinetic properties of artemether, lumefantrine, and their active metabolites in children, especially desbutyl-lumefantrine. We studied 13 Papua New Guinean children aged 5 to 10 years with uncomplicated malaria who received the six recommended doses of artemether (1.7 mg/kg of body weight) plus lumefantrine (10 mg/kg), given with fat over 3 days. Intensive blood sampling was carried out over 42 days. Plasma artemether, dihydroartemisinin, lumefantrine, and desbutyl-lumefantrine were assayed using liquid chromatography-mass spectrometry or high-performance liquid chromatography. Multicompartmental pharmacokinetic models for a drug plus its metabolite were developed using a population approach that included plasma artemether and dihydroartemisinin concentrations below the limit of quantitation. Although artemether bioavailability was variable and its clearance increased by 67.8% with each dose, the median areas under the plasma concentration-time curve from 0 h to infinity (AUC(0-∞)s) for artemether and dihydroartemisinin (3,063 and 2,839 μg · h/liter, respectively) were similar to those reported previously in adults with malaria. For lumefantrine, the median AUC(0-∞) (459,980 μg · h/liter) was also similar to that in adults with malaria. These data support the higher dose recommended for children weighing 15 to 35 kg (35% higher than that for a 50-kg adult) but question the recommendation for a lower dose in children weighing 12.5 to 15 kg. The median desbutyl-lumefantrine/lumefantrine ratio in the children in our study was 1.13%, within the range reported for adults and higher at later time points because of the longer desbutyl-lumefantrine terminal elimination half-life. A combined desbutyl-lumefantrine and lumefantrine AUC(0-∞) weighted on in vitro antimalarial activity was inversely associated with recurrent parasitemia, suggesting that both the parent drug and the metabolite contribute to the treatment outcome of artemether-lumefantrine.
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