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Cavany S, Nanyonga S, Hauk C, Lim C, Tarning J, Sartorius B, Dolecek C, Caillet C, Newton PN, Cooper BS. The uncertain role of substandard and falsified medicines in the emergence and spread of antimicrobial resistance. Nat Commun 2023; 14:6153. [PMID: 37788991 PMCID: PMC10547756 DOI: 10.1038/s41467-023-41542-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: 03/16/2023] [Accepted: 09/07/2023] [Indexed: 10/05/2023] Open
Abstract
Approximately 10% of antimicrobials used by humans in low- and middle-income countries are estimated to be substandard or falsified. In addition to their negative impact on morbidity and mortality, they may also be important drivers of antimicrobial resistance. Despite such concerns, our understanding of this relationship remains rudimentary. Substandard and falsified medicines have the potential to either increase or decrease levels of resistance, and here we discuss a range of mechanisms that could drive these changes. Understanding these effects and their relative importance will require an improved understanding of how different drug exposures affect the emergence and spread of resistance and of how the percentage of active pharmaceutical ingredients in substandard and falsified medicines is temporally and spatially distributed.
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Affiliation(s)
- Sean Cavany
- NDM Centre for Global Health Research, Centre for Tropical Medicine and Global Health, Nuffield Department of Medicine, University of Oxford, Oxford, UK.
| | - Stella Nanyonga
- NDM Centre for Global Health Research, Centre for Tropical Medicine and Global Health, Nuffield Department of Medicine, University of Oxford, Oxford, UK
- Medicine Quality Research Group, Centre for Tropical Medicine and Global Health, Nuffield Department of Medicine, University of Oxford, Oxford, UK
- Infectious Diseases Data Observatory, Centre for Tropical Medicine and Global Health, Nuffield Department of Medicine, University of Oxford, Oxford, UK
- Mahidol Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand
| | - Cathrin Hauk
- NDM Centre for Global Health Research, Centre for Tropical Medicine and Global Health, Nuffield Department of Medicine, University of Oxford, Oxford, UK
- Medicine Quality Research Group, Centre for Tropical Medicine and Global Health, Nuffield Department of Medicine, University of Oxford, Oxford, UK
- Infectious Diseases Data Observatory, Centre for Tropical Medicine and Global Health, Nuffield Department of Medicine, University of Oxford, Oxford, UK
- Mahidol Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand
| | - Cherry Lim
- NDM Centre for Global Health Research, Centre for Tropical Medicine and Global Health, Nuffield Department of Medicine, University of Oxford, Oxford, UK
- Mahidol Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand
| | - Joel Tarning
- NDM Centre for Global Health Research, Centre for Tropical Medicine and Global Health, Nuffield Department of Medicine, University of Oxford, Oxford, UK
- Infectious Diseases Data Observatory, Centre for Tropical Medicine and Global Health, Nuffield Department of Medicine, University of Oxford, Oxford, UK
- Mahidol Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand
| | - Benn Sartorius
- NDM Centre for Global Health Research, Centre for Tropical Medicine and Global Health, Nuffield Department of Medicine, University of Oxford, Oxford, UK
- School of Public Health, Faculty of Medicine, The University of Queensland, St Lucia, Australia
| | - Christiane Dolecek
- NDM Centre for Global Health Research, Centre for Tropical Medicine and Global Health, Nuffield Department of Medicine, University of Oxford, Oxford, UK
- Mahidol Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand
| | - Céline Caillet
- NDM Centre for Global Health Research, Centre for Tropical Medicine and Global Health, Nuffield Department of Medicine, University of Oxford, Oxford, UK
- Medicine Quality Research Group, Centre for Tropical Medicine and Global Health, Nuffield Department of Medicine, University of Oxford, Oxford, UK
- Infectious Diseases Data Observatory, Centre for Tropical Medicine and Global Health, Nuffield Department of Medicine, University of Oxford, Oxford, UK
- Mahidol Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand
| | - Paul N Newton
- NDM Centre for Global Health Research, Centre for Tropical Medicine and Global Health, Nuffield Department of Medicine, University of Oxford, Oxford, UK
- Medicine Quality Research Group, Centre for Tropical Medicine and Global Health, Nuffield Department of Medicine, University of Oxford, Oxford, UK
- Infectious Diseases Data Observatory, Centre for Tropical Medicine and Global Health, Nuffield Department of Medicine, University of Oxford, Oxford, UK
- Mahidol Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand
| | - Ben S Cooper
- NDM Centre for Global Health Research, Centre for Tropical Medicine and Global Health, Nuffield Department of Medicine, University of Oxford, Oxford, UK.
- Mahidol Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand.
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2
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Sagna AB, Zéla L, Ouedraogo COW, Pooda SH, Porciani A, Furnival-Adams J, Lado P, Somé AF, Pennetier C, Chaccour CJ, Dabiré RK, Mouline K. Ivermectin as a novel malaria control tool: Getting ahead of the resistance curse. Acta Trop 2023; 245:106973. [PMID: 37352998 DOI: 10.1016/j.actatropica.2023.106973] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2023] [Revised: 06/14/2023] [Accepted: 06/16/2023] [Indexed: 06/25/2023]
Abstract
Reduction in malaria clinical cases is strongly dependent on the ability to prevent Anopheles infectious bites. Vector control strategies using long-lasting insecticidal nets and indoor residual spraying with insecticides have contributed to significantly reduce the incidence of malaria in many endemic countries, especially in the Sub-Saharan region. However, global progress in reducing malaria cases has plateaued since 2015 mostly due to the increased insecticide resistance and behavioral changes in Anopheles vectors. Additional control strategies are thus required to further reduce the burden of malaria and contain the spread of resistant and invasive Anopheles vectors. The use of endectocides such as ivermectin as an additional malaria control tool is now receiving increased attention, driven by its different mode of action compared to insecticides used so far and its excellent safety record for humans. In this opinion article, we discuss the advantages and disadvantages of using ivermectin for malaria control with a focus on the risk of selecting ivermectin resistance in malaria vectors. We also highlight the importance of understanding how ivermectin resistance could develop in mosquitoes and what its underlying mechanisms and associated molecular markers are, and propose a research agenda to manage this phenomenon.
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Affiliation(s)
- André B Sagna
- MIVEGEC, University of Montpellier, IRD, CNRS, Montpellier, France.
| | - Lamidi Zéla
- Centre International de Recherche-Développement sur l'Elevage en zone Subhumide, Bobo-Dioulasso, Burkina Faso
| | - Cheick Oumar W Ouedraogo
- Institut de Recherche en Sciences de la Santé, Direction Régionale de l'Ouest, Centre National de Recherche Scientifique et Technologique, Bobo-Dioulasso, Burkina Faso
| | - Sié H Pooda
- Centre International de Recherche-Développement sur l'Elevage en zone Subhumide, Bobo-Dioulasso, Burkina Faso; Université de Dédougou, Dédougou, Burkina Faso
| | | | | | - Paula Lado
- Center for Vector-borne Infectious Diseases, Colorado State University, Fort Collins, CO, USA
| | - Anyirékun F Somé
- Institut de Recherche en Sciences de la Santé, Direction Régionale de l'Ouest, Centre National de Recherche Scientifique et Technologique, Bobo-Dioulasso, Burkina Faso
| | - Cédric Pennetier
- MIVEGEC, University of Montpellier, IRD, CNRS, Montpellier, France
| | - Carlos J Chaccour
- ISGlobal, Barcelona Institute for Global Health, Barcelona, Spain; Centro de Investigación Biomédica en Red de Enfermedades Infecciosas, Madrid, Spain; Universidad de Navarra, Pamplona, Spain
| | - Roch K Dabiré
- Institut de Recherche en Sciences de la Santé, Direction Régionale de l'Ouest, Centre National de Recherche Scientifique et Technologique, Bobo-Dioulasso, Burkina Faso
| | - Karine Mouline
- MIVEGEC, University of Montpellier, IRD, CNRS, Montpellier, France
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Stadler E, Maiga M, Friedrich L, Thathy V, Demarta-Gatsi C, Dara A, Sogore F, Striepen J, Oeuvray C, Djimdé AA, Lee MCS, Dembélé L, Fidock DA, Khoury DS, Spangenberg T. Propensity of selecting mutant parasites for the antimalarial drug cabamiquine. Nat Commun 2023; 14:5205. [PMID: 37626093 PMCID: PMC10457284 DOI: 10.1038/s41467-023-40974-8] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2022] [Accepted: 08/17/2023] [Indexed: 08/27/2023] Open
Abstract
We report an analysis of the propensity of the antimalarial agent cabamiquine, a Plasmodium-specific eukaryotic elongation factor 2 inhibitor, to select for resistant Plasmodium falciparum parasites. Through in vitro studies of laboratory strains and clinical isolates, a humanized mouse model, and volunteer infection studies, we identified resistance-associated mutations at 11 amino acid positions. Of these, six (55%) were present in more than one infection model, indicating translatability across models. Mathematical modelling suggested that resistant mutants were likely pre-existent at the time of drug exposure across studies. Here, we estimated a wide range of frequencies of resistant mutants across the different infection models, much of which can be attributed to stochastic differences resulting from experimental design choices. Structural modelling implicates binding of cabamiquine to a shallow mRNA binding site adjacent to two of the most frequently identified resistance mutations.
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Affiliation(s)
- Eva Stadler
- The Kirby Institute, UNSW Sydney, Kensington, NSW, 2052, Australia
| | - Mohamed Maiga
- Université des Sciences, des Techniques et des Technologies de Bamako (USTTB), Faculté de Pharmacie, Malaria Research and Training Center (MRTC), Point G, PB1805, Bamako, Mali
| | - Lukas Friedrich
- Medicinal Chemistry & Drug Design Global Research & Development, Discovery Technologies, Merck Healthcare, 64293, Darmstadt, Germany
| | - Vandana Thathy
- Department of Microbiology and Immunology, Columbia University Irving Medical Center, New York, NY, 10032, USA
- Center for Malaria Therapeutics and Antimicrobial Resistance, Columbia University Irving Medical Center, New York, NY, 10032, USA
| | - Claudia Demarta-Gatsi
- Global Health Institute of Merck, Ares Trading S.A., (an affiliate of Merck KGaA, Darmstadt, Germany), 1262, Eysins, Switzerland
| | - Antoine Dara
- Université des Sciences, des Techniques et des Technologies de Bamako (USTTB), Faculté de Pharmacie, Malaria Research and Training Center (MRTC), Point G, PB1805, Bamako, Mali
| | - Fanta Sogore
- Université des Sciences, des Techniques et des Technologies de Bamako (USTTB), Faculté de Pharmacie, Malaria Research and Training Center (MRTC), Point G, PB1805, Bamako, Mali
| | - Josefine Striepen
- Department of Microbiology and Immunology, Columbia University Irving Medical Center, New York, NY, 10032, USA
- Weill Cornell Medical College, New York, NY, 10021, USA
| | - Claude Oeuvray
- Global Health Institute of Merck, Ares Trading S.A., (an affiliate of Merck KGaA, Darmstadt, Germany), 1262, Eysins, Switzerland
| | - Abdoulaye A Djimdé
- Université des Sciences, des Techniques et des Technologies de Bamako (USTTB), Faculté de Pharmacie, Malaria Research and Training Center (MRTC), Point G, PB1805, Bamako, Mali
| | - Marcus C S Lee
- Wellcome Sanger Institute, Wellcome Genome Campus, CB10 1SA, Hinxton, UK
- Biological Chemistry and Drug Discovery, School of Life Sciences, University of Dundee, DD1 4HN, Scotland, UK
| | - Laurent Dembélé
- Université des Sciences, des Techniques et des Technologies de Bamako (USTTB), Faculté de Pharmacie, Malaria Research and Training Center (MRTC), Point G, PB1805, Bamako, Mali.
| | - David A Fidock
- Department of Microbiology and Immunology, Columbia University Irving Medical Center, New York, NY, 10032, USA.
- Center for Malaria Therapeutics and Antimicrobial Resistance, Columbia University Irving Medical Center, New York, NY, 10032, USA.
- Division of Infectious Diseases, Department of Medicine, Columbia University Irving Medical Center, New York, NY, 10032, USA.
| | - David S Khoury
- The Kirby Institute, UNSW Sydney, Kensington, NSW, 2052, Australia.
| | - Thomas Spangenberg
- Global Health Institute of Merck, Ares Trading S.A., (an affiliate of Merck KGaA, Darmstadt, Germany), 1262, Eysins, Switzerland.
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Gachie B, Thiong'o K, Muriithi B, Chepngetich J, Onchieku N, Gathirwa J, Mwitari P, Magoma G, Kiboi D, Kimani F. Prevalence of mutations in the cysteine desulfurase IscS (Pfnfs1) gene in recurrent Plasmodium falciparum infections following artemether-lumefantrine (AL) and dihydroartemisinin-piperaquine (DP) treatment in Matayos, Western Kenya. Malar J 2023; 22:158. [PMID: 37202779 DOI: 10.1186/s12936-023-04587-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2023] [Accepted: 05/11/2023] [Indexed: 05/20/2023] Open
Abstract
BACKGROUND Malaria remains a public health concern globally. Resistance to anti-malarial drugs has consistently threatened the gains in controlling the malaria parasites. Currently, artemether-lumefantrine (AL) and dihydroartemisinin-piperaquine (DP) are the treatment regimens against Plasmodium falciparum infections in many African countries, including Kenya. Recurrent infections have been reported in patients treated with AL or DP, suggesting the possibility of reinfection or parasite recrudescence associated with the development of resistance against the two therapies. The Plasmodium falciparum cysteine desulfurase IscS (Pfnfs1) K65 selection marker has previously been associated with decreased lumefantrine susceptibility. This study evaluated the frequency of the Pfnfs1 K65 resistance marker and associated K65Q resistant allele in recurrent infections collected from P. falciparum-infected individuals living in Matayos, Busia County, in western Kenya. METHODS Archived dried blood spots (DBS) of patients with recurrent malaria infection on clinical follow-up days after treatment with either AL or DP were used in the study. After extraction of genomic DNA, PCR amplification and sequencing analysis were employed to determine the frequencies of the Pfnfs1 K65 resistance marker and K65Q mutant allele in the recurrent infections. Plasmodium falciparum msp1 and P. falciparum msp2 genetic markers were used to distinguish recrudescent infections from new infections. RESULTS The K65 wild-type allele was detected at a frequency of 41% while the K65Q mutant allele was detected at a frequency of 22% in the recurrent samples. 58% of the samples containing the K65 wild-type allele were AL treated samples and while 42% were DP treated samples. 79% of the samples with the K65Q mutation were AL treated samples and 21% were DP treated samples. The K65 wild-type allele was detected in three recrudescent infections (100%) identified from the AL treated samples. The K65 wild-type allele was detected in two recrudescent DP treated samples (67%) while the K65Q mutant allele was identified in one DP treated (33%) recrudescent sample. CONCLUSIONS The data demonstrate a higher frequency of the K65 resistance marker in patients with recurrent infection during the study period. The study underscores the need for consistent monitoring of molecular markers of resistance in regions of high malaria transmission.
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Affiliation(s)
- Beatrice Gachie
- Department of Molecular Biology and Biotechnology, Pan African University Institute for Basic Sciences, Technology and Innovation, P.O. Box 62000-00200, Nairobi, Kenya.
- Centre for Traditional Medicine and Drug Research (CTMDR), Kenya Medical Research Institute, Off Raila Odinga Way, P.O. Box 54840-00200, Nairobi, Kenya.
- Centre for Biotechnology Research and Development (CBRD), Kenya Medical Research Institute, Off Raila Odinga Way, P.O. Box 54840-00200, Nairobi, Kenya.
| | - Kelvin Thiong'o
- Centre for Biotechnology Research and Development (CBRD), Kenya Medical Research Institute, Off Raila Odinga Way, P.O. Box 54840-00200, Nairobi, Kenya
| | - Brenda Muriithi
- Centre for Traditional Medicine and Drug Research (CTMDR), Kenya Medical Research Institute, Off Raila Odinga Way, P.O. Box 54840-00200, Nairobi, Kenya
- Centre for Biotechnology Research and Development (CBRD), Kenya Medical Research Institute, Off Raila Odinga Way, P.O. Box 54840-00200, Nairobi, Kenya
| | - Jean Chepngetich
- Department of Molecular Biology and Biotechnology, Pan African University Institute for Basic Sciences, Technology and Innovation, P.O. Box 62000-00200, Nairobi, Kenya
- Centre for Traditional Medicine and Drug Research (CTMDR), Kenya Medical Research Institute, Off Raila Odinga Way, P.O. Box 54840-00200, Nairobi, Kenya
- Centre for Biotechnology Research and Development (CBRD), Kenya Medical Research Institute, Off Raila Odinga Way, P.O. Box 54840-00200, Nairobi, Kenya
| | - Noah Onchieku
- Centre for Biotechnology Research and Development (CBRD), Kenya Medical Research Institute, Off Raila Odinga Way, P.O. Box 54840-00200, Nairobi, Kenya
| | - Jeremiah Gathirwa
- Centre for Traditional Medicine and Drug Research (CTMDR), Kenya Medical Research Institute, Off Raila Odinga Way, P.O. Box 54840-00200, Nairobi, Kenya
| | - Peter Mwitari
- Centre for Traditional Medicine and Drug Research (CTMDR), Kenya Medical Research Institute, Off Raila Odinga Way, P.O. Box 54840-00200, Nairobi, Kenya
| | - Gabriel Magoma
- Department of Molecular Biology and Biotechnology, Pan African University Institute for Basic Sciences, Technology and Innovation, P.O. Box 62000-00200, Nairobi, Kenya
- Department of Biochemistry, Jomo Kenyatta University of Agriculture and Technology (JKUAT), P.O. Box 62000 -00200, Nairobi, Kenya
| | - Daniel Kiboi
- Department of Biochemistry, Jomo Kenyatta University of Agriculture and Technology (JKUAT), P.O. Box 62000 -00200, Nairobi, Kenya
| | - Francis Kimani
- Centre for Biotechnology Research and Development (CBRD), Kenya Medical Research Institute, Off Raila Odinga Way, P.O. Box 54840-00200, Nairobi, Kenya
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Plowe CV. Malaria chemoprevention and drug resistance: a review of the literature and policy implications. Malar J 2022; 21:104. [PMID: 35331231 PMCID: PMC8943514 DOI: 10.1186/s12936-022-04115-8] [Citation(s) in RCA: 52] [Impact Index Per Article: 26.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2022] [Accepted: 03/03/2022] [Indexed: 01/19/2023] Open
Abstract
Chemoprevention strategies reduce malaria disease and death, but the efficacy of anti-malarial drugs used for chemoprevention is perennially threatened by drug resistance. This review examines the current impact of chemoprevention on the emergence and spread of drug resistant malaria, and the impact of drug resistance on the efficacy of each of the chemoprevention strategies currently recommended by the World Health Organization, namely, intermittent preventive treatment in pregnancy (IPTp); intermittent preventive treatment in infants (IPTi); seasonal malaria chemoprevention (SMC); and mass drug administration (MDA) for the reduction of disease burden in emergency situations. While the use of drugs to prevent malaria often results in increased prevalence of genetic mutations associated with resistance, malaria chemoprevention interventions do not inevitably lead to meaningful increases in resistance, and even high rates of resistance do not necessarily impair chemoprevention efficacy. At the same time, it can reasonably be anticipated that, over time, as drugs are widely used, resistance will generally increase and efficacy will eventually be lost. Decisions about whether, where and when chemoprevention strategies should be deployed or changed will continue to need to be made on the basis of imperfect evidence, but practical considerations such as prevalence patterns of resistance markers can help guide policy recommendations.
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Temporal distribution of Plasmodium falciparum recrudescence following artemisinin-based combination therapy: an individual participant data meta-analysis. Malar J 2022; 21:106. [PMID: 35331243 PMCID: PMC8943927 DOI: 10.1186/s12936-021-03980-z] [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: 02/25/2021] [Accepted: 11/12/2021] [Indexed: 01/12/2023] Open
Abstract
BACKGROUND The duration of trial follow-up affects the ability to detect recrudescent infections following anti-malarial treatment. The aim of this study was to explore the proportions of recrudescent parasitaemia as ascribed by genotyping captured at various follow-up time-points in treatment efficacy trials for uncomplicated Plasmodium falciparum malaria. METHODS Individual patient data from 83 anti-malarial efficacy studies collated in the WorldWide Antimalarial Resistance Network (WWARN) repository with at least 28 days follow-up were available. The temporal and cumulative distributions of recrudescence were characterized using a Cox regression model with shared frailty on study-sites. Fractional polynomials were used to capture non-linear instantaneous hazard. The area under the density curve (AUC) of the constructed distribution was used to estimate the optimal follow-up period for capturing a P. falciparum malaria recrudescence. Simulation studies were conducted based on the constructed distributions to quantify the absolute overestimation in efficacy due to sub-optimal follow-up. RESULTS Overall, 3703 recurrent infections were detected in 60 studies conducted in Africa (15,512 children aged < 5 years) and 23 studies conducted in Asia and South America (5272 patients of all ages). Using molecular genotyping, 519 (14.0%) recurrences were ascribed as recrudescent infections. A 28 day artemether-lumefantrine (AL) efficacy trial would not have detected 58% [95% confidence interval (CI) 47-74%] of recrudescences in African children and 32% [95% CI 15-45%] in patients of all ages in Asia/South America. The corresponding estimate following a 42 day dihydroartemisinin-piperaquine (DP) efficacy trial in Africa was 47% [95% CI 19-90%] in children under 5 years old treated with > 48 mg/kg total piperaquine (PIP) dose and 9% [95% CI 0-22%] in those treated with ≤ 48 mg/kg PIP dose. In absolute terms, the simulation study found that trials limited to 28 days follow-up following AL underestimated the risk of recrudescence by a median of 2.8 percentage points compared to day 63 estimates and those limited to 42 days following DP underestimated the risk of recrudescence by a median of 2.0 percentage points compared to day 42 estimates. The analysis was limited by few clinical trials following patients for longer than 42 days (9 out of 83 trials) and the imprecision of PCR genotyping which overcalls recrudescence in areas of higher transmission biasing the later distribution. CONCLUSIONS Restricting follow-up of clinical efficacy trials to day 28 for AL and day 42 for DP will miss a proportion of late recrudescent treatment failures but will have a modest impact in derived efficacy. The results highlight that as genotyping methods improve consideration should be given for trials with longer duration of follow-up to detect early indications of emerging drug resistance.
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Wallender E, Ali AM, Hughes E, Kakuru A, Jagannathan P, Muhindo MK, Opira B, Whalen M, Huang L, Duvalsaint M, Legac J, Kamya MR, Dorsey G, Aweeka F, Rosenthal PJ, Savic RM. Identifying an optimal dihydroartemisinin-piperaquine dosing regimen for malaria prevention in young Ugandan children. Nat Commun 2021; 12:6714. [PMID: 34795281 PMCID: PMC8602248 DOI: 10.1038/s41467-021-27051-8] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2021] [Accepted: 10/29/2021] [Indexed: 12/01/2022] Open
Abstract
Intermittent preventive treatment (IPT) with dihydroartemisinin-piperaquine (DP) is highly protective against malaria in children, but is not standard in malaria-endemic countries. Optimal DP dosing regimens will maximize efficacy and reduce toxicity and resistance selection. We analyze piperaquine (PPQ) concentrations (n = 4573), malaria incidence data (n = 326), and P. falciparum drug resistance markers from a trial of children randomized to IPT with DP every 12 weeks (n = 184) or every 4 weeks (n = 96) from 2 to 24 months of age (NCT02163447). We use nonlinear mixed effects modeling to establish malaria protective PPQ levels and risk factors for suboptimal protection. Compared to DP every 12 weeks, DP every 4 weeks is associated with 95% protective efficacy (95% CI: 84-99%). A PPQ level of 15.4 ng/mL reduces the malaria hazard by 95%. Malnutrition reduces PPQ exposure. In simulations, we show that DP every 4 weeks is optimal across a range of transmission intensities, and age-based dosing improves malaria protection in young or malnourished children.
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Affiliation(s)
- Erika Wallender
- grid.266102.10000 0001 2297 6811Department of Clinical Pharmacy, University of California, San Francisco, San Francisco, CA USA
| | - Ali Mohamed Ali
- grid.266102.10000 0001 2297 6811Department of Bioengineering and Therapeutic Sciences, University of California, San Francisco, San Francisco, CA USA
| | - Emma Hughes
- grid.266102.10000 0001 2297 6811Department of Bioengineering and Therapeutic Sciences, University of California, San Francisco, San Francisco, CA USA
| | - Abel Kakuru
- grid.463352.5Infectious Diseases Research Collaboration, Kampala, Uganda
| | - Prasanna Jagannathan
- grid.168010.e0000000419368956Department of Medicine, Stanford University, Palo Alto, CA USA
| | | | - Bishop Opira
- grid.463352.5Infectious Diseases Research Collaboration, Kampala, Uganda
| | - Meghan Whalen
- grid.266102.10000 0001 2297 6811Department of Clinical Pharmacy, University of California, San Francisco, San Francisco, CA USA
| | - Liusheng Huang
- grid.266102.10000 0001 2297 6811Department of Clinical Pharmacy, University of California, San Francisco, San Francisco, CA USA
| | - Marvin Duvalsaint
- grid.266102.10000 0001 2297 6811Department of Medicine, University of California, San Francisco, San Francisco, CA USA
| | - Jenny Legac
- grid.266102.10000 0001 2297 6811Department of Medicine, University of California, San Francisco, San Francisco, CA USA
| | - Moses R. Kamya
- grid.463352.5Infectious Diseases Research Collaboration, Kampala, Uganda ,grid.11194.3c0000 0004 0620 0548Department of Medicine, Makerere University, Kampala, Uganda
| | - Grant Dorsey
- grid.266102.10000 0001 2297 6811Department of Medicine, University of California, San Francisco, San Francisco, CA USA
| | - Francesca Aweeka
- grid.266102.10000 0001 2297 6811Department of Clinical Pharmacy, University of California, San Francisco, San Francisco, CA USA
| | - Philip J. Rosenthal
- grid.266102.10000 0001 2297 6811Department of Medicine, University of California, San Francisco, San Francisco, CA USA
| | - Rada M. Savic
- grid.266102.10000 0001 2297 6811Department of Bioengineering and Therapeutic Sciences, University of California, San Francisco, San Francisco, CA USA
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Assefa DG, Yismaw G, Makonnen E. Efficacy of dihydroartemisinin-piperaquine versus artemether-lumefantrine for the treatment of uncomplicated Plasmodium falciparum malaria among children in Africa: a systematic review and meta-analysis of randomized control trials. Malar J 2021; 20:340. [PMID: 34384431 PMCID: PMC8359548 DOI: 10.1186/s12936-021-03873-1] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2021] [Accepted: 08/03/2021] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Emergence of Plasmodium falciparum resistance to artemisinin and its derivatives poses a threat to the global effort to control malaria. The emergence of anti-malarial resistance has become a great public health challenge and continues to be a leading threat to ongoing malaria control efforts. The aim of this review was to synthesize available evidence on the efficacy of dihydroartemisinin-piperaquine (DHA-PQ) compared to artemether-lumefantrine (AL) for the treatment of uncomplicated falciparum malaria among children in Africa. METHODS A systematic literature search was done to identify relevant articles from online databases PubMed/ MEDLINE, Embase, and Cochrane Central Register of Controlled Trials' database (CENTRAL) for retrieving randomized control trials comparing efficacy of DHA-PQ and AL for treatment of uncomplicated falciparum malaria in African children. The search was performed from August 2020 to April 2021. Using Rev-Man software (V5.4.1), R-studio and Comprehensive Meta-analysis software version 3, the extracted data from eligible studies were pooled as risk ratio (RR) with 95% confidence interval (CI). RESULTS In this review, 25 studies which involved a total of 13,198 participants were included. PCR-unadjusted treatment failure in children aged between 6 months and 15 years was significantly lower in the DHA-PQ treatment arm on day 28 than that of AL (RR 0.14, 95% CI 0.08-0.26; participants = 1302; studies = 4; I2 = 0%, high quality of evidence). Consistently, the PCR-adjusted treatment failure was significantly lower with DHA-PQ treatment group on day 28 (RR 0.45, 95% CI 0.29-0.68; participants = 8508; studies = 16; I2 = 51%, high quality of evidence) and on day 42 (RR 0.60, 95% CI 0.47-0.78; participants = 5959; studies = 17; I2 = 0%, high quality of evidence). However, the efficacy was ≥ 95% in both treatment groups on day 28. CONCLUSION From this review, it can be concluded that DHA-PQ reduces new infection and recrudescence on days 28 and 42 more than AL. This may trigger DHA-PQ to become a first-line treatment option.
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Affiliation(s)
- Dawit Getachew Assefa
- Center for Innovative Drug Development and Therapeutic Trials for Africa (CDT-Africa), College of Health Sciences, Addis Ababa University, Addis Ababa, Ethiopia. .,Department of Nursing, College of Health Science and Medicine, Dilla University, Dilla, Ethiopia.
| | - Gizachew Yismaw
- Center for Innovative Drug Development and Therapeutic Trials for Africa (CDT-Africa), College of Health Sciences, Addis Ababa University, Addis Ababa, Ethiopia
| | - Eyasu Makonnen
- Center for Innovative Drug Development and Therapeutic Trials for Africa (CDT-Africa), College of Health Sciences, Addis Ababa University, Addis Ababa, Ethiopia.,Department of Pharmacology and Clinical Pharmacy, College of Health Sciences, Addis Ababa University, Addis Ababa, Ethiopia
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Kaur R, Gorki V, Katare OP, Dhingra N, Chauhan M, Kaur R, Nirmalan N, Singh B. Improved biopharmaceutical attributes of lumefantrine using choline mimicking drug delivery system: preclinical investigation on NK-65 P.berghei murine model. Expert Opin Drug Deliv 2021; 18:1533-1552. [PMID: 34176411 DOI: 10.1080/17425247.2021.1946512] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
Abstract
BACKGROUND Lumefantrine (LMF) is first-line antimalarial drug, possesses activity against almost all human malarial parasites, but the in vivo activity of this molecule gets thwarted due to its low and inconsistent oral bioavailability (i.e. 4-12%) owing to poor biopharmaceutical attributes. METHODS Lumefantrine phospholipid complex (LMF-PC) was prepared by rota-evaporation method following job's plot technique for the selection of apt stoichiometric ratios. Docking studies were carried out to determine the possible interaction(s) of LMF with phosphatidylcholine analogue. Comparative in vitro physiochemical, solid-state characterization, MTT assay, dose-response on P. falciparum, in vivo efficacy studies including pharmacokinetic and chemosuppression on NK-65 P. berghei infected mice were carried out. RESULTS Aqueous solubility was distinctly improved (i.e. 345 times) with phospholipid complex of LMF. Cytotoxicity studies on Hela and fibroblast cell lines demonstrated safety of LMF-PC with selectivity indices of 4395 and 5139, respectively. IC50 value was reduced almost 2.5 folds. Significant enhancement in Cmax (3.3-folds) and AUC (2.7-folds) of rat plasma levels indicated notable pharmacokinetic superiority of LMF-PC over LMF suspension. Differential leukocytic count and cytokine assay delineated plausible immunoregulatory role of LMF-PC with nearly 98% chemosuppression and over 30 days of post-survival. CONCLUSION Superior antimalarial efficacy and survival time with full recovery of infected mice revealed through histopathological studies.
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Affiliation(s)
- Ripandeep Kaur
- UGC Centre of Advanced Studies, University Institute of Pharmaceutical Sciences, Panjab University, Chandigarh, India.,School of Science, Engineering & Environment, University of Salford, Manchester, UK.,UGC-Centre of Excellence in Nano Applications (Biomedical Sciences), Panjab University, Chandigarh, India
| | - Varun Gorki
- Parasitology Laboratory, Department of Zoology, Panjab University, Chandigarh, India
| | - O P Katare
- UGC Centre of Advanced Studies, University Institute of Pharmaceutical Sciences, Panjab University, Chandigarh, India
| | - Neelima Dhingra
- UGC Centre of Advanced Studies, University Institute of Pharmaceutical Sciences, Panjab University, Chandigarh, India
| | - Monika Chauhan
- UGC Centre of Advanced Studies, University Institute of Pharmaceutical Sciences, Panjab University, Chandigarh, India
| | - Ranjot Kaur
- UGC Centre of Advanced Studies, University Institute of Pharmaceutical Sciences, Panjab University, Chandigarh, India
| | - Niroshini Nirmalan
- School of Science, Engineering & Environment, University of Salford, Manchester, UK
| | - Bhupinder Singh
- UGC Centre of Advanced Studies, University Institute of Pharmaceutical Sciences, Panjab University, Chandigarh, India.,UGC-Centre of Excellence in Nano Applications (Biomedical Sciences), Panjab University, Chandigarh, India
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10
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Carvalho PM, Makowski M, Domingues MM, Martins IC, Santos NC. Lipid membrane-based therapeutics and diagnostics. Arch Biochem Biophys 2021; 704:108858. [PMID: 33798534 DOI: 10.1016/j.abb.2021.108858] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2020] [Revised: 03/20/2021] [Accepted: 03/22/2021] [Indexed: 12/29/2022]
Abstract
Success rates in drug discovery are extremely low, and the imbalance between new drugs entering clinical research and their approval is steadily widening. Among the causes of the failure of new therapeutic agents are the lack of safety and insufficient efficacy. On the other hand, timely disease diagnosis may enable an early management of the disease, generally leading to better and less costly outcomes. Several strategies have been explored to overcome the barriers for drug development and facilitate diagnosis. Using lipid membranes as platforms for drug delivery or as biosensors are promising strategies, due to their biocompatibility and unique physicochemical properties. We examine some of the lipid membrane-based strategies for drug delivery and diagnostics, including their advantages and shortcomings. Regarding synthetic lipid membrane-based strategies for drug delivery, liposomes are the archetypic example of a successful approach, already with a long period of well-succeeded clinical application. The use of lipid membrane-based structures from biological sources as drug carriers, currently under clinical evaluation, is also discussed. These biomimetic strategies can enhance the in vivo lifetime of drug and delivery system by avoiding fast clearance, consequently increasing their therapeutic window. The strategies under development using lipid membranes for diagnostic purposes are also reviewed.
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Affiliation(s)
- Patrícia M Carvalho
- Instituto de Medicina Molecular, Faculdade de Medicina, Universidade de Lisboa, Av. Prof. Egas Moniz, 1649-028, Lisbon, Portugal
| | - Marcin Makowski
- Instituto de Medicina Molecular, Faculdade de Medicina, Universidade de Lisboa, Av. Prof. Egas Moniz, 1649-028, Lisbon, Portugal
| | - Marco M Domingues
- Instituto de Medicina Molecular, Faculdade de Medicina, Universidade de Lisboa, Av. Prof. Egas Moniz, 1649-028, Lisbon, Portugal
| | - Ivo C Martins
- Instituto de Medicina Molecular, Faculdade de Medicina, Universidade de Lisboa, Av. Prof. Egas Moniz, 1649-028, Lisbon, Portugal
| | - Nuno C Santos
- Instituto de Medicina Molecular, Faculdade de Medicina, Universidade de Lisboa, Av. Prof. Egas Moniz, 1649-028, Lisbon, Portugal.
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11
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Natama HM, Toussaint R, Bazié DLC, Samadoulougou S, Coulibaly-Traoré M, Tinto H, Kirakoya-Samadoulougou F. Prevalence and factors associated with carriage of Pfmdr1 polymorphisms among pregnant women receiving intermittent preventive treatment with sulfadoxine-pyrimethamine (IPTp-SP) and artemether-lumefantrine for malaria treatment in Burkina Faso. Malar J 2020; 19:399. [PMID: 33172485 PMCID: PMC7653827 DOI: 10.1186/s12936-020-03473-5] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2020] [Accepted: 10/31/2020] [Indexed: 11/11/2022] Open
Abstract
Background Single nucleotide polymorphisms occurring in the Plasmodium falciparum multidrug resistant gene 1 (pfmdr1) are known to be associated with aminoquinoline resistance and, therefore, represent key P. falciparum markers for monitoring resistance both in susceptible groups (children under 5 years old and pregnant women) and in the general population. This study aimed to determine prevalence and factors associated with the carriage of pfmdr1 N86Y, Y184F and D1246Y polymorphisms among pregnant women in a setting of high malaria transmission in Burkina Faso. Methods Plasmodium falciparum isolates were collected at the first antenatal care visit (ANC-1) as well as at delivery from pregnant women participating in the COSMIC trial (NTC01941264), which assessed malaria preventive interventions during pregnancy in the Nanoro Health District. Here, pregnant women received intermittent preventive treatment with sulfadoxine-pyrimethamine (IPTp-SP) and malaria infections and/or diseases were treated using artemether-lumefantrine (AL) during the trial. Parasite DNA was extracted from dried blood spots and the presence of pfmdr1 mutations at positions 86, 184 and 1246 was determined using nested PCR, followed by restriction fragment length polymorphism (RFLP) analysis. Results A prevalence of 13.2% (20/151) and 12.1% (14/116) of the pfmdr1 86Y mutant allele was found at ANC-1 and at delivery, respectively, while no mutant allele was observed for Y184F and D1246Y codons at both ANC-1 and at delivery. There were no significant factors associated with pfmdr1 86Y mutant allele carriage at ANC-1. However, malaria infections at delivery with a parasite density above the median (2237.2 (IQR: 613.5–11,425.7) parasites/µl) was associated with an increase risk of pfmdr1 86Y mutant allele carriage (AOR = 5.5 (95% CI 1.07–28.0); P = 0.04). In contrast, both three or more IPTp-SP doses (AOR = 0.25 (95% CI 0.07–0.92); P = 0.04) and one or more AL treatment (AOR = 0.25 (95% CI 0.07–0.89); P = 0.03) during pregnancy were associated with a significant reduce risk of pfmdr1 86Y mutant allele carriage at delivery. Conclusion These findings suggest that both high coverage of IPTp-SP and the use of AL for the treatment of malaria infection/disease during pregnancy select for pfmdr1 N86 wild-type allele at delivery.
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Affiliation(s)
- Hamtandi Magloire Natama
- Unité de Recherche Clinique de Nanoro, Institut de Recherche en Sciences de la Santé, Nanoro, Burkina Faso.
| | - Rouamba Toussaint
- Unité de Recherche Clinique de Nanoro, Institut de Recherche en Sciences de la Santé, Nanoro, Burkina Faso.,Centre D'Epidémiologie, Biostatistique Et Recherche Clinique, Ecole de Santé Publique, Université Libre de Bruxelles (ULB), Bruxelles, Belgium
| | - Djamina Line Cerine Bazié
- Unité de Recherche Clinique de Nanoro, Institut de Recherche en Sciences de la Santé, Nanoro, Burkina Faso
| | - Sékou Samadoulougou
- Centre for Research On Planning and Development (CRAD), Laval University, Quebec, Canada.,Evaluation Platform On Obesity Prevention, Quebec Heart and Lung Institute, Quebec, Canada
| | - Maminata Coulibaly-Traoré
- Unité de Recherche Clinique de Nanoro, Institut de Recherche en Sciences de la Santé, Nanoro, Burkina Faso
| | - Halidou Tinto
- Unité de Recherche Clinique de Nanoro, Institut de Recherche en Sciences de la Santé, Nanoro, Burkina Faso
| | - Fati Kirakoya-Samadoulougou
- Centre D'Epidémiologie, Biostatistique Et Recherche Clinique, Ecole de Santé Publique, Université Libre de Bruxelles (ULB), Bruxelles, Belgium
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12
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Khoury DS, Cao P, Zaloumis SG, Davenport MP. Artemisinin Resistance and the Unique Selection Pressure of a Short-acting Antimalarial. Trends Parasitol 2020; 36:884-887. [DOI: 10.1016/j.pt.2020.07.004] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2020] [Revised: 07/03/2020] [Accepted: 07/08/2020] [Indexed: 01/05/2023]
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13
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Choi R, Michaels SA, Onu EC, Hulverson MA, Saha A, Coker ME, Weeks JC, Van Voorhis WC, Ojo KK. Taming the Boys for Global Good: Contraceptive Strategy to Stop Malaria Transmission. Molecules 2020; 25:molecules25122773. [PMID: 32560085 PMCID: PMC7356879 DOI: 10.3390/molecules25122773] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2020] [Revised: 06/10/2020] [Accepted: 06/14/2020] [Indexed: 12/21/2022] Open
Abstract
Transmission of human malaria parasites (Plasmodium spp.) by Anopheles mosquitoes is a continuous process that presents a formidable challenge for effective control of the disease. Infectious gametocytes continue to circulate in humans for up to four weeks after antimalarial drug treatment, permitting prolonged transmission to mosquitoes even after clinical cure. Almost all reported malaria cases are transmitted to humans by mosquitoes, and therefore decreasing the rate of Plasmodium transmission from humans to mosquitoes with novel transmission-blocking remedies would be an important complement to other interventions in reducing malaria incidence.
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Affiliation(s)
- Ryan Choi
- Center for Emerging and Re-Emerging Infectious Diseases (CERID), Division of Allergy and Infectious Diseases, Department of Medicine, University of Washington, Seattle, WA 98109, USA; (R.C.); (S.A.M.); (M.A.H.); (A.S.); (W.C.V.V.)
| | - Samantha A. Michaels
- Center for Emerging and Re-Emerging Infectious Diseases (CERID), Division of Allergy and Infectious Diseases, Department of Medicine, University of Washington, Seattle, WA 98109, USA; (R.C.); (S.A.M.); (M.A.H.); (A.S.); (W.C.V.V.)
| | - Emmanuel C. Onu
- Department of Pharmaceutical Microbiology, Faculty of Pharmacy, University of Ibadan, Ibadan, Nigeria; (E.C.O.); (M.E.C.)
| | - Matthew A. Hulverson
- Center for Emerging and Re-Emerging Infectious Diseases (CERID), Division of Allergy and Infectious Diseases, Department of Medicine, University of Washington, Seattle, WA 98109, USA; (R.C.); (S.A.M.); (M.A.H.); (A.S.); (W.C.V.V.)
| | - Aparajita Saha
- Center for Emerging and Re-Emerging Infectious Diseases (CERID), Division of Allergy and Infectious Diseases, Department of Medicine, University of Washington, Seattle, WA 98109, USA; (R.C.); (S.A.M.); (M.A.H.); (A.S.); (W.C.V.V.)
| | - Morenike E. Coker
- Department of Pharmaceutical Microbiology, Faculty of Pharmacy, University of Ibadan, Ibadan, Nigeria; (E.C.O.); (M.E.C.)
| | - Janis C. Weeks
- Department of Biology, University of Oregon, Eugene, OR 97403, USA;
| | - Wesley C. Van Voorhis
- Center for Emerging and Re-Emerging Infectious Diseases (CERID), Division of Allergy and Infectious Diseases, Department of Medicine, University of Washington, Seattle, WA 98109, USA; (R.C.); (S.A.M.); (M.A.H.); (A.S.); (W.C.V.V.)
| | - Kayode K. Ojo
- Center for Emerging and Re-Emerging Infectious Diseases (CERID), Division of Allergy and Infectious Diseases, Department of Medicine, University of Washington, Seattle, WA 98109, USA; (R.C.); (S.A.M.); (M.A.H.); (A.S.); (W.C.V.V.)
- Correspondence: ; Tel.: +1-206-543-0821
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14
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A Computer Modelling Approach To Evaluate the Accuracy of Microsatellite Markers for Classification of Recurrent Infections during Routine Monitoring of Antimalarial Drug Efficacy. Antimicrob Agents Chemother 2020; 64:AAC.01517-19. [PMID: 31932376 DOI: 10.1128/aac.01517-19] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2019] [Accepted: 01/06/2020] [Indexed: 12/23/2022] Open
Abstract
Antimalarial drugs have long half-lives, so clinical trials to monitor their efficacy require long periods of follow-up to capture drug failure that may become patent only weeks after treatment. Reinfections often occur during follow-up, so robust methods of distinguishing drug failures (recrudescence) from emerging new infections are needed to produce accurate failure rate estimates. Molecular correction aims to achieve this by comparing the genotype of a patient's pretreatment (initial) blood sample with that of any infection that occurs during follow-up, with matching genotypes indicating drug failure. We use an in silico approach to show that the widely used match-counting method of molecular correction with microsatellite markers is likely to be highly unreliable and may lead to gross under- or overestimates of the true failure rates, depending on the choice of matching criterion. A Bayesian algorithm for molecular correction was previously developed and utilized for analysis of in vivo efficacy trials. We validated this algorithm using in silico data and showed it had high specificity and generated accurate failure rate estimates. This conclusion was robust for multiple drugs, different levels of drug failure rates, different levels of transmission intensity in the study sites, and microsatellite genetic diversity. The Bayesian algorithm was inherently unable to accurately identify low-density recrudescence that occurred in a small number of patients, but this did not appear to compromise its utility as a highly effective molecular correction method for analyzing microsatellite genotypes. Strong consideration should be given to using Bayesian methodology to obtain accurate failure rate estimates during routine monitoring trials of antimalarial efficacy that use microsatellite markers.
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Conrad MD, Rosenthal PJ. Antimalarial drug resistance in Africa: the calm before the storm? THE LANCET. INFECTIOUS DISEASES 2019; 19:e338-e351. [DOI: 10.1016/s1473-3099(19)30261-0] [Citation(s) in RCA: 130] [Impact Index Per Article: 26.0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/09/2019] [Revised: 04/09/2019] [Accepted: 05/09/2019] [Indexed: 11/26/2022]
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16
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Improving Methods for Analyzing Antimalarial Drug Efficacy Trials: Molecular Correction Based on Length-Polymorphic Markers msp-1, msp-2, and glurp. Antimicrob Agents Chemother 2019; 63:AAC.00590-19. [PMID: 31307982 PMCID: PMC6709465 DOI: 10.1128/aac.00590-19] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2019] [Accepted: 07/02/2019] [Indexed: 01/14/2023] Open
Abstract
Drug efficacy trials monitor the continued efficacy of front-line drugs against falciparum malaria. Overestimating efficacy results in a country retaining a failing drug as first-line treatment with associated increases in morbidity and mortality, while underestimating drug effectiveness leads to removal of an effective treatment with substantial practical and economic implications. Drug efficacy trials monitor the continued efficacy of front-line drugs against falciparum malaria. Overestimating efficacy results in a country retaining a failing drug as first-line treatment with associated increases in morbidity and mortality, while underestimating drug effectiveness leads to removal of an effective treatment with substantial practical and economic implications. Trials are challenging: they require long durations of follow-up to detect drug failures, and patients are frequently reinfected during that period. Molecular correction based on parasite genotypes distinguishes reinfections from drug failures to ensure the accuracy of failure rate estimates. Several molecular correction “algorithms” have been proposed, but which is most accurate and/or robust remains unknown. We used pharmacological modeling to simulate parasite dynamics and genetic signals that occur in patients enrolled in malaria drug clinical trials. We compared estimates of treatment failure obtained from a selection of proposed molecular correction algorithms against the known “true” failure rate in the model. Our findings are as follows. (i) Molecular correction is essential to avoid substantial overestimates of drug failure rates. (ii) The current WHO-recommended algorithm consistently underestimates the true failure rate. (iii) Newly proposed algorithms produce more accurate failure rate estimates; the most accurate algorithm depends on the choice of drug, trial follow-up length, and transmission intensity. (iv) Long durations of patient follow-up may be counterproductive; large numbers of new infections accumulate and may be misclassified, overestimating drug failure rate. (v) Our model was highly consistent with existing in vivo data. The current WHO-recommended method for molecular correction and analysis of clinical trials should be reevaluated and updated.
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Burns AL, Dans MG, Balbin JM, de Koning-Ward TF, Gilson PR, Beeson JG, Boyle MJ, Wilson DW. Targeting malaria parasite invasion of red blood cells as an antimalarial strategy. FEMS Microbiol Rev 2019; 43:223-238. [PMID: 30753425 PMCID: PMC6524681 DOI: 10.1093/femsre/fuz005] [Citation(s) in RCA: 41] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2018] [Accepted: 02/11/2019] [Indexed: 12/20/2022] Open
Abstract
Plasmodium spp. parasites that cause malaria disease remain a significant global-health burden. With the spread of parasites resistant to artemisinin combination therapies in Southeast Asia, there is a growing need to develop new antimalarials with novel targets. Invasion of the red blood cell by Plasmodium merozoites is essential for parasite survival and proliferation, thus representing an attractive target for therapeutic development. Red blood cell invasion requires a co-ordinated series of protein/protein interactions, protease cleavage events, intracellular signals, organelle release and engagement of an actin-myosin motor, which provide many potential targets for drug development. As these steps occur in the bloodstream, they are directly susceptible and exposed to drugs. A number of invasion inhibitors against a diverse range of parasite proteins involved in these different processes of invasion have been identified, with several showing potential to be optimised for improved drug-like properties. In this review, we discuss red blood cell invasion as a drug target and highlight a number of approaches for developing antimalarials with invasion inhibitory activity to use in future combination therapies.
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Affiliation(s)
- Amy L Burns
- Research Centre for Infectious Diseases, School of Biological Sciences, University of Adelaide, Adelaide, Australia 5005
| | - Madeline G Dans
- Burnet Institute, Melbourne, Victoria, Australia 3004.,Deakin University, School of Medicine, Waurn Ponds, Victoria, Australia 3216
| | - Juan M Balbin
- Research Centre for Infectious Diseases, School of Biological Sciences, University of Adelaide, Adelaide, Australia 5005
| | | | - Paul R Gilson
- Burnet Institute, Melbourne, Victoria, Australia 3004
| | - James G Beeson
- Burnet Institute, Melbourne, Victoria, Australia 3004.,Central Clinical School and Department of Microbiology, Monash University 3004.,Department of Medicine, University of Melbourne, Australia 3052
| | - Michelle J Boyle
- Burnet Institute, Melbourne, Victoria, Australia 3004.,QIMR Berghofer Medical Research Institute, Herston, Queensland, Australia 4006
| | - Danny W Wilson
- Research Centre for Infectious Diseases, School of Biological Sciences, University of Adelaide, Adelaide, Australia 5005.,Burnet Institute, Melbourne, Victoria, Australia 3004
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Lee TE, Penny MA. Identifying key factors of the transmission dynamics of drug-resistant malaria. J Theor Biol 2019; 462:210-220. [DOI: 10.1016/j.jtbi.2018.10.050] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2018] [Revised: 10/15/2018] [Accepted: 10/25/2018] [Indexed: 11/30/2022]
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19
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Modeling Prevention of Malaria and Selection of Drug Resistance with Different Dosing Schedules of Dihydroartemisinin-Piperaquine Preventive Therapy during Pregnancy in Uganda. Antimicrob Agents Chemother 2019; 63:AAC.01393-18. [PMID: 30530597 DOI: 10.1128/aac.01393-18] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2018] [Accepted: 11/24/2018] [Indexed: 11/20/2022] Open
Abstract
Dihydroartemisinin-piperaquine (DHA-PQ) is under study for intermittent preventive treatment during pregnancy (IPTp), but it may accelerate selection for drug resistance. Understanding the relationships between piperaquine concentration, prevention of parasitemia, and selection for decreased drug sensitivity can inform control policies and optimization of DHA-PQ dosing. Piperaquine concentrations, measures of parasitemia, and Plasmodium falciparum genotypes associated with decreased aminoquinoline sensitivity in Africa (pfmdr1 86Y, pfcrt 76T) were obtained from pregnant Ugandan women randomized to IPTp with sulfadoxine-pyrimethamine (SP) or DHA-PQ. Joint pharmacokinetic/pharmacodynamic models described relationships between piperaquine concentration and the probability of genotypes of interest using nonlinear mixed effects modeling. An increase in the piperaquine plasma concentration was associated with a log-linear decrease in risk of parasitemia. Our models predicted that higher median piperaquine concentrations would be required to provide 99% protection against mutant infections than against wild-type infections (pfmdr1: N86, 9.6 ng/ml; 86Y, 19.6 ng/ml; pfcrt: K76, 6.5 ng/ml; 76T, 19.6 ng/ml). Comparing monthly, weekly, and daily dosing, daily low-dose DHA-PQ was predicted to result in the fewest infections and the fewest mutant infections per 1,000 pregnancies (predicted mutant infections for pfmdr1 86Y: SP monthly, 607; DHA-PQ monthly, 198; DHA-PQ daily, 1; for pfcrt 76T: SP monthly, 1,564; DHA-PQ monthly, 283; DHA-PQ daily, 1). Our models predict that higher piperaquine concentrations are needed to prevent infections with the pfmdr1/pfcrt mutant compared to those with wild-type parasites and that, despite selection for mutants by DHA-PQ, the overall burden of mutant infections is lower for IPTp with DHA-PQ than for IPTp with SP. (This study has been registered at ClinicalTrials.gov under identifier NCT02282293.).
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Zuber JA, Takala-Harrison S. Multidrug-resistant malaria and the impact of mass drug administration. Infect Drug Resist 2018. [PMID: 29535546 PMCID: PMC5840189 DOI: 10.2147/idr.s123887] [Citation(s) in RCA: 27] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022] Open
Abstract
Based on the emergence and spread throughout the Greater Mekong Subregion (GMS) of multiple artemisinin-resistant lineages, the prevalence of multidrug resistance leading to high rates of artemisinin-based combination treatment failure in parts of the GMS, and the declining malaria burden in the region, the World Health Organization has recommended complete elimination of falciparum malaria from the GMS. Mass drug administration (MDA) is being piloted as one elimination intervention to be employed as part of this effort. However, concerns remain as to whether MDA might exacerbate the already prevalent problem of multidrug resistance in the region. In this review, we briefly discuss challenges of MDA, the use of MDA in the context of multidrug-resistant malaria, and the potential of different drug combinations and drug-based elimination strategies for mitigating the emergence and spread of resistance.
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Affiliation(s)
- Janie Anne Zuber
- Division of Malaria Research, Institute for Global Health, University of Maryland School of Medicine, Baltimore, MD, USA
| | - Shannon Takala-Harrison
- Division of Malaria Research, Institute for Global Health, University of Maryland School of Medicine, Baltimore, MD, USA
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Fukuda MM, Krudsood S, Mohamed K, Green JA, Warrasak S, Noedl H, Euswas A, Ittiverakul M, Buathong N, Sriwichai S, Miller RS, Ohrt C. A randomized, double-blind, active-control trial to evaluate the efficacy and safety of a three day course of tafenoquine monotherapy for the treatment of Plasmodium vivax malaria. PLoS One 2017; 12:e0187376. [PMID: 29121061 PMCID: PMC5679603 DOI: 10.1371/journal.pone.0187376] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2017] [Accepted: 10/09/2017] [Indexed: 12/19/2022] Open
Abstract
Background Tafenoquine is an investigational 8-aminoquinoline for the prevention of Plasmodium vivax relapse. Tafenoquine has a long half-life and the potential for more convenient dosing, compared with the currently recommended 14-day primaquine regimen. Methods This randomized, active-control, double-blind trial was conducted in Bangkok, Thailand. Seventy patients with microscopically confirmed P. vivax were randomized (2:1) to tafenoquine 400 mg once daily for 3 days or 2500 mg total dose chloroquine phosphate (1500 mg chloroquine base) given over 3 days plus primaquine 15 mg daily for 14 days. Patients were followed to day 120. Results Day 28 adequate clinical response rate in the per-protocol population was 93% (40/43) (90%CI 83–98%) with tafenoquine, and 100% (22/22) (90%CI 87–100%) with chloroquine/primaquine. Day 120 relapse prevention was 100% (35/35) with tafenoquine (90%CI 92–100%), and 95% (19/20) (90%CI 78–100%) with chloroquine/primaquine. Mean (SD) parasite, gametocyte and fever clearance times with tafenoquine were 82.5 h (32.3), 49.1 h (33.0), and 41.1 h (31.4) versus 40.0 h (15.7), 22.7 h (16.4), and 24.7 h (17.7) with chloroquine/primaquine, respectively. Peak methemoglobin was 1.4–25.6% (median 7.4%, mean 9.1%) in the tafenoquine arm, and 0.5–5.9% (median 1.5%, mean 1.9%) in the chloroquine/primaquine arm. There were no clinical symptoms of methemoglobinemia in any patient. Discussion Although there was no difference in efficacy in this study, the slow rate of parasite, gametocyte and fever clearance indicates that tafenoquine should not be used as monotherapy for radical cure of P. vivax malaria. Also, monotherapy increases the potential risk of resistance developing to this long-acting agent. Clinical trials of single-dose tafenoquine 300 mg combined with standard 3-day chloroquine or artemisinin-based combination therapy are ongoing. Trial registration Clinicaltrials.gov NCT01290601
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Affiliation(s)
- Mark M. Fukuda
- Armed Forces Research Institute of Medical Science, Bangkok, Thailand
- * E-mail:
| | | | - Khadeeja Mohamed
- GlaxoSmithKline Research and Development, Uxbridge, Middlesex, United Kingdom
| | - Justin A. Green
- GlaxoSmithKline Research and Development, Uxbridge, Middlesex, United Kingdom
| | | | - Harald Noedl
- Armed Forces Research Institute of Medical Science, Bangkok, Thailand
| | - Ataya Euswas
- Ramathibodi Hospital, Mahidol University, Bangkok, Thailand
| | - Mali Ittiverakul
- Armed Forces Research Institute of Medical Science, Bangkok, Thailand
| | - Nillawan Buathong
- Armed Forces Research Institute of Medical Science, Bangkok, Thailand
| | | | - R. Scott Miller
- Armed Forces Research Institute of Medical Science, Bangkok, Thailand
| | - Colin Ohrt
- Walter Reed Army Institute of Research, Silver Spring, Maryland, United States of America
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22
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Gatton ML, Dunn J, Chaudhry A, Ciketic S, Cunningham J, Cheng Q. Implications of Parasites Lacking Plasmodium falciparum Histidine-Rich Protein 2 on Malaria Morbidity and Control When Rapid Diagnostic Tests Are Used for Diagnosis. J Infect Dis 2017; 215:1156-1166. [DOI: 10.1093/infdis/jix094] [Citation(s) in RCA: 42] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2016] [Accepted: 02/14/2017] [Indexed: 01/01/2023] Open
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Mwebaza N, Jerling M, Gustafsson LL, Silva AV, Pohanka A, Obua C, Waako P, Beck O, Homann MV, Färnert A, Hellgren U. Oil-Fortified Maize Porridge Increases Absorption of Lumefantrine in Children with Uncomplicated Falciparum Malaria. Basic Clin Pharmacol Toxicol 2017; 120:457-465. [PMID: 27883269 DOI: 10.1111/bcpt.12714] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2016] [Accepted: 10/10/2016] [Indexed: 11/27/2022]
Abstract
Artemether-lumefantrine (AL) is a first-line treatment for uncomplicated malaria. Absorption of lumefantrine (LUM) is fat dependent, and in children, intake is recommended with milk. We investigated whether oil-fortified maize porridge can be an alternative when milk is not available. In an open-label pharmacokinetic study, Ugandan children <5 years with uncomplicated Plasmodium falciparum malaria were randomized to receive standard six-dose AL treatment [one tablet (20 mgA/120 mg LUM) if <15 kg and two tablets if >15 kg] with milk (A) or maize porridge plus oil (B). Parametric two-sample t-test was used to compare relative oral LUM bioavailability. The primary end-point was LUM exposure till 8 hr after the first dose (AUC0-8 hr ). Secondary outcome included day 7 concentrations (d7LUM ), LUM exposure between days 7 and 28 (AUCd7-28 ) and day 28 PCR-adjusted parasitological response. Evaluable children (n = 33) included 16 in arm A and 17 in arm B. The AUC0-8 hr was comparable between A and B [geometric mean (95% CI): 6.01 (3.26-11.1) versus 6.26 (4.5-8.43) hr*μg/mL, p = 0.9]. Less interindividual variability in AUC0-8 hr was observed in B (p = 0.01), but d7LUM and AUCd7-28 were comparable. Children receiving two tablets had significantly higher exposure than those receiving one tablet [median d7LUM (505 versus 289 ng/mL, p = 0.02) and AUCd7-28 (108 versus 41 hr*μg/mL, p = 0.006)]. One parasitological failure (d28 recrudescence) was observed. Our findings suggest that oil-fortified maize porridge can be an alternative to milk in augmenting absorption of LUM. The lower LUM exposure observed in children dosed with one AL tablet needs further attention.
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Affiliation(s)
- Norah Mwebaza
- Division of Clinical Pharmacology, Department of Laboratory Medicine, Karolinska Institute Huddinge, Stockholm, Sweden.,Department of Pharmacology and Therapeutics, School of Biomedical Sciences, Makerere University College of Health Sciences, Kampala, Uganda
| | | | - Lars L Gustafsson
- Division of Clinical Pharmacology, Department of Laboratory Medicine, Karolinska Institute Huddinge, Stockholm, Sweden
| | - Antero V Silva
- Division of Clinical Pharmacology, Department of Laboratory Medicine, Karolinska Institute Huddinge, Stockholm, Sweden
| | - Anton Pohanka
- Division of Clinical Pharmacology, Department of Laboratory Medicine, Karolinska Institute Huddinge, Stockholm, Sweden
| | - Celestino Obua
- Department of Pharmacology and Therapeutics, School of Biomedical Sciences, Makerere University College of Health Sciences, Kampala, Uganda
| | - Paul Waako
- Department of Pharmacology and Therapeutics, School of Biomedical Sciences, Makerere University College of Health Sciences, Kampala, Uganda
| | - Olof Beck
- Division of Clinical Pharmacology, Department of Laboratory Medicine, Karolinska Institute Huddinge, Stockholm, Sweden
| | - Manijeh Vafa Homann
- Department of Infectious Diseases, Karolinska University Hospital, Stockholm, Sweden.,Unit of Infectious Diseases, Department of Medicine Solna, Karolinska Institute, Stockholm, Sweden
| | - Anna Färnert
- Department of Infectious Diseases, Karolinska University Hospital, Stockholm, Sweden.,Unit of Infectious Diseases, Department of Medicine Solna, Karolinska Institute, Stockholm, Sweden
| | - Urban Hellgren
- Department of Infectious Diseases, Karolinska University Hospital, Stockholm, Sweden.,Unit of Infectious Diseases, Department of Medicine Huddinge, Karolinska Institute, Stockholm, Sweden
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24
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Does antimalarial mass drug administration increase or decrease the risk of resistance? THE LANCET. INFECTIOUS DISEASES 2016; 17:e15-e20. [PMID: 27839929 DOI: 10.1016/s1473-3099(16)30269-9] [Citation(s) in RCA: 43] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/07/2016] [Revised: 06/28/2016] [Accepted: 07/14/2016] [Indexed: 11/20/2022]
Abstract
All antimalarial drugs developed so far have eventually succumbed to resistance. There is a general belief that the more people that are exposed to an antimalarial drug, the more likely it is that resistance will emerge. Mass drug administration (MDA) is therefore considered a potent cause of antimalarial drug resistance. In this Personal View, I discuss the circumstances under which antimalarial MDA increases or decreases the risk of resistance. It is the total number of parasites exposed and their individual probabilities of survival and spread that determine the risk, not the number of people that contain them. In malaria-endemic areas, a substantial proportion of the community carries malaria parasites in their blood without being ill. Although many more people have asymptomatic than symptomatic malaria at any time, their parasite burdens are several orders of magnitude lower, and their host defence mechanisms are substantially more effective. Symptomatic infections with high parasite numbers are the most likely source of resistance emergence, so effective mass treatment that reduces the number of symptomatic cases of malaria and its transmission can reduce the threat of antimalarial resistance emerging and spreading in treated populations.
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Hastings IM, Hodel EM, Kay K. Quantifying the pharmacology of antimalarial drug combination therapy. Sci Rep 2016; 6:32762. [PMID: 27604175 PMCID: PMC5036534 DOI: 10.1038/srep32762] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2016] [Accepted: 08/12/2016] [Indexed: 12/31/2022] Open
Abstract
Most current antimalarial drugs are combinations of an artemisinin plus a
‘partner’ drug from another class, and are known as
artemisinin-based combination therapies (ACTs). They are the frontline drugs in
treating human malaria infections. They also have a public-health role as an
essential component of recent, comprehensive scale-ups of malaria interventions and
containment efforts conceived as part of longer term malaria elimination efforts.
Recent reports that resistance has arisen to artemisinins has caused considerable
concern. We investigate the likely impact of artemisinin resistance by quantifying
the contribution artemisinins make to the overall therapeutic capacity of ACTs. We
achieve this using a simple, easily understood, algebraic approach and by more
sophisticated pharmacokinetic/pharmacodynamic analyses of drug action; the two
approaches gave consistent results. Surprisingly, the artemisinin component
typically makes a negligible contribution (≪0.0001%) to the therapeutic
capacity of the most widely used ACTs and only starts to make a significant
contribution to therapeutic outcome once resistance has started to evolve to the
partner drugs. The main threat to antimalarial drug effectiveness and control comes
from resistance evolving to the partner drugs. We therefore argue that public health
policies be re-focussed to maximise the likely long-term effectiveness of the
partner drugs.
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Affiliation(s)
- Ian M Hastings
- Liverpool School of Tropical Medicine, Liverpool L3 5QA, United Kingdom
| | - Eva Maria Hodel
- Liverpool School of Tropical Medicine, Liverpool L3 5QA, United Kingdom
| | - Katherine Kay
- Liverpool School of Tropical Medicine, Liverpool L3 5QA, United Kingdom
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26
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Incorporating Stage-Specific Drug Action into Pharmacological Modeling of Antimalarial Drug Treatment. Antimicrob Agents Chemother 2016; 60:2747-56. [PMID: 26902760 PMCID: PMC4862506 DOI: 10.1128/aac.01172-15] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2015] [Accepted: 02/06/2016] [Indexed: 01/02/2023] Open
Abstract
Pharmacological modeling of antiparasitic treatment based on a drug's pharmacokinetic and pharmacodynamic properties plays an increasingly important role in identifying optimal drug dosing regimens and predicting their potential impact on control and elimination programs. Conventional modeling of treatment relies on methods that do not distinguish between parasites at different developmental stages. This is problematic for malaria parasites, as their sensitivity to drugs varies substantially during their 48-h developmental cycle. We investigated four drug types (short or long half-lives with or without stage-specific killing) to quantify the accuracy of the standard methodology. The treatment dynamics of three drug types were well characterized with standard modeling. The exception were short-half-life drugs with stage-specific killing (i.e., artemisinins) because, depending on time of treatment, parasites might be in highly drug-sensitive stages or in much less sensitive stages. We describe how to bring such drugs into pharmacological modeling by including additional variation into the drug's maximal killing rate. Finally, we show that artemisinin kill rates may have been substantially overestimated in previous modeling studies because (i) the parasite reduction ratio (PRR) (generally estimated to be 10(4)) is based on observed changes in circulating parasite numbers, which generally overestimate the "true" PRR, which should include both circulating and sequestered parasites, and (ii) the third dose of artemisinin at 48 h targets exactly those stages initially hit at time zero, so it is incorrect to extrapolate the PRR measured over 48 h to predict the impact of doses at 48 h and later.
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Cairns ME, Walker PGT, Okell LC, Griffin JT, Garske T, Asante KP, Owusu-Agyei S, Diallo D, Dicko A, Cisse B, Greenwood BM, Chandramohan D, Ghani AC, Milligan PJ. Seasonality in malaria transmission: implications for case-management with long-acting artemisinin combination therapy in sub-Saharan Africa. Malar J 2015; 14:321. [PMID: 26283418 PMCID: PMC4539702 DOI: 10.1186/s12936-015-0839-4] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2015] [Accepted: 08/06/2015] [Indexed: 01/15/2023] Open
Abstract
Background Long-acting artemisinin-based combination therapy (LACT) offers the potential to prevent recurrent malaria attacks in highly exposed children. However, it is not clear where this advantage will be most important, and deployment of these drugs is not rationalized on this basis. Methods To understand where post-treatment prophylaxis would be most beneficial, the relationship between seasonality, transmission intensity and the interval between malaria episodes was explored using data from six cohort studies in West Africa and an individual-based malaria transmission model. The total number of recurrent malaria cases per 1000 child-years at risk, and the fraction of the total annual burden that this represents were estimated for sub-Saharan Africa. Results In settings where prevalence is less than 10 %, repeat malaria episodes constitute a small fraction of the total burden, and few repeat episodes occur within the window of protection provided by currently available drugs. However, in higher transmission settings, and particularly in high transmission settings with highly seasonal transmission, repeat malaria becomes increasingly important, with up to 20 % of the total clinical burden in children estimated to be due to repeat episodes within 4 weeks of a prior attack. Conclusion At a given level of transmission intensity and annual incidence, the concentration of repeat malaria episodes in time, and consequently the protection from LACT is highest in the most seasonal areas. As a result, the degree of seasonality, in addition to the overall intensity of transmission, should be considered by policy makers when deciding between ACT that differ in their duration of post-treatment prophylaxis. Electronic supplementary material The online version of this article (doi:10.1186/s12936-015-0839-4) contains supplementary material, which is available to authorized users.
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Affiliation(s)
| | - Patrick G T Walker
- MRC Centre for Outbreak Analysis and Modelling, Imperial College London, London, UK.
| | - Lucy C Okell
- MRC Centre for Outbreak Analysis and Modelling, Imperial College London, London, UK.
| | - Jamie T Griffin
- MRC Centre for Outbreak Analysis and Modelling, Imperial College London, London, UK.
| | - Tini Garske
- MRC Centre for Outbreak Analysis and Modelling, Imperial College London, London, UK.
| | | | | | - Diadier Diallo
- Faculty of Infectious and Tropical Diseases, LSHTM, London, UK. .,PATH-Malaria Vaccine Initiative, Dakar, Senegal.
| | | | - Badara Cisse
- Faculty of Infectious and Tropical Diseases, LSHTM, London, UK. .,Université Cheikh Anta Diop, Dakar, Sénégal.
| | | | | | - Azra C Ghani
- MRC Centre for Outbreak Analysis and Modelling, Imperial College London, London, UK.
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Mekonnen SK, Medhin G, Berhe N, Clouse RM, Aseffa A. Efficacy of artemether-lumefantrine therapy for the treatment of uncomplicated Plasmodium falciparum malaria in Southwestern Ethiopia. Malar J 2015; 14:317. [PMID: 26271736 PMCID: PMC4536736 DOI: 10.1186/s12936-015-0826-9] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2015] [Accepted: 07/29/2015] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND The development and spread of chloroquine-resistant Plasmodium falciparum threatens the health of millions of people and poses a major challenge to the control of malaria. Monitoring drug efficacy in 2-year intervals is an important tool for establishing rational anti-malarial drug policies. This study addresses the therapeutic efficacy of artemether-lumefantrine (AL) for the treatment of Plasmodium falciparum in southwestern Ethiopia. METHODS A 28-day in vivo therapeutic efficacy study was conducted from September to December, 2011, in southwestern Ethiopia. Participants were selected for the study if they were older than 6 months, weighed more than 5 kg, symptomatic, and had microscopically confirmed, uncomplicated P. falciparum. All 93 eligible patients were treated with AL and followed for 28 days. For each patient, recurrence of parasitaemia, the clinical condition, and the presence of gametoytes were assessed on each visit during the follow-up period. PCR was conducted to differentiate re-infection from recrudescence. RESULTS Seventy-four (83.1 %) of the study subjects cleared fever by day 1, but five (5.6 %) had fever at day 2. All study subjects cleared fever by day 3. Seventy-nine (88.8 %) of the study subjects cleared the parasite by day 1, seven (7.9 %) were blood-smear positive by day 1, and three (3.4 %) were positive by day 2. In five patients (5.6 %), parasitaemia reappeared during the 28-day follow-up period. From these five, one (1.1 %) was a late clinical failure, and four (4.5 %) were a late parasitological failure. On the day of recurrent parasitaemia, the level of chloroquine/desethylchloroquine (CQ-DCQ) was above the minimum effective concentration (>100 ng/ml) in one patient. There were 84 (94.4 %) adequate clinical and parasitological responses. The 28-day, PCR-uncorrected (unadjusted by genotyping) cure rate was 84 (94.4 %), whereas the 28-day, PCR-corrected cure rate was 87 (97.8 %). Of the three re-infections, two (2.2 %) were due to P. falciparum and one (1.1 %) was due to P. vivax. From 89 study subjects, 12 (13.5 %) carried P. falciparum gametocytes at day 0, whereas the 28-day gametocyte carriage rate was 2 (2.2 %). CONCLUSIONS Years after the introduction of AL in Ethiopia, the finding of this study is that AL has been highly effective in the treatment of uncomplicated P. falciparum malaria and reducing gametocyte carriage in southwestern Ethiopia.
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Affiliation(s)
- Seleshi Kebede Mekonnen
- College of Health Siences, Jimma University, Jimma, Ethiopia. .,Armauer Hansen Research Institute, Addis Ababa, Ethiopia.
| | - Girmay Medhin
- Aklilu Lemma Institute of Pathobiology, Addis Ababa University, Addis Ababa, Ethiopia.
| | - Nega Berhe
- Aklilu Lemma Institute of Pathobiology, Addis Ababa University, Addis Ababa, Ethiopia. .,Ethiopia and Centre for Imported and Tropical Diseases, Oslo University Hospital-Ulleval, Oslo, Norway.
| | - Ronald M Clouse
- Department of Bioinformatics and Genomics, University of North Carolina at Charlotte, Charlotte, NC, USA.
| | - Abraham Aseffa
- Armauer Hansen Research Institute, Addis Ababa, Ethiopia.
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Kay K, Hastings IM. Measuring windows of selection for anti-malarial drug treatments. Malar J 2015; 14:292. [PMID: 26228915 PMCID: PMC4521485 DOI: 10.1186/s12936-015-0810-4] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2015] [Accepted: 07/15/2015] [Indexed: 11/28/2022] Open
Abstract
BACKGROUND The long half-lives of malaria 'partner' drugs are a potent force selecting for drug resistance. Clinical trials can quantify this effect by estimating a window of selection (WoS), defined as the amount of time post-treatment when drug levels are sufficiently high that resistant parasites can re-establish an infection while preventing drug-sensitive parasites from establishing viable infections. METHODS The ability of clinical data to accurately estimate the true WoS was investigated using standard pharmacokinetic-pharmacodynamic models for three widely used malaria drugs: artemether-lumefantrine (AR-LF), artesunate-mefloquine (AS-MQ) and dihydroartemisinin-piperaquine (DHA-PPQ). Estimates of the clinical WoS either (1) ignored all new infections occurring after the 63-day follow-up period, as is currently done in clinical trials, or, (2) recognized that all individuals would eventually be re-infected and arbitrarily assigned them a new infection day. RESULTS The results suggest current methods of estimating the clinical WoS underestimate the true WoS by as much as 9 days for AR-LF, 33 days for AS-MQ and 7 days for DHA-PPQ. The new method of estimating clinical WoS (i.e., retaining all individuals in the analysis) was significantly better at estimating the true WoS for AR-LF and AS-MQ. CONCLUSIONS Previous studies, based on clinically observed WoS, have probably underestimated the 'true' WoS and hence the role of drugs with long half-lives in driving resistance. This has important policy implications: high levels of drug use are inevitable in mass drug administration programmes and intermittent preventative treatment programmes and the analysis herein suggests these policies will be far more potent drivers of resistance than previously thought.
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Affiliation(s)
- Katherine Kay
- Parasitology Group, Liverpool School of Tropical Medicine, Pembroke Place, Liverpool, L3 5QA, UK.
| | - Ian M Hastings
- Parasitology Group, Liverpool School of Tropical Medicine, Pembroke Place, Liverpool, L3 5QA, UK.
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30
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von Seidlein L, Dondorp A. Fighting fire with fire: mass antimalarial drug administrations in an era of antimalarial resistance. Expert Rev Anti Infect Ther 2015; 13:715-30. [PMID: 25831482 DOI: 10.1586/14787210.2015.1031744] [Citation(s) in RCA: 70] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
The emergence and spread of antimalarial resistance has been a major liability for malaria control. The spread of chloroquine-resistant Plasmodium falciparum strains had catastrophic consequences for people in malaria-endemic regions, particularly in sub-Saharan Africa. The recent emergence of artemisinin-resistant P. falciparum strains is of highest concern. Current efforts to contain artemisinin resistance have yet to show success. In the absence of more promising plans, it has been suggested to eliminate falciparum malaria from foci of artemisinin resistance using a multipronged approach, including mass drug administrations. The use of mass drug administrations is controversial as it increases drug pressure. Based on current knowledge it is difficult to conceptualize how targeted malaria elimination could contribute to artemisinin resistance, provided a full treatment course is ensured.
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Affiliation(s)
- Lorenz von Seidlein
- Mahidol-Oxford Tropical Medicine Research Unit (MORU) - Faculty of Tropical Medicine, 420/6 Rajvithi Road Bangkok 10400, Thailand
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31
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Laman M, Benjamin JM, Moore BR, Salib M, Tawat S, Davis WA, Siba PM, Robinson LJ, Davis TME. Artemether-lumefantrine versus artemisinin-naphthoquine in Papua New Guinean children with uncomplicated malaria: a six months post-treatment follow-up study. Malar J 2015; 14:121. [PMID: 25889150 PMCID: PMC4374335 DOI: 10.1186/s12936-015-0624-4] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2015] [Accepted: 02/20/2015] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND In a recent trial of artemisinin-naphthoquine (artemisinin-NQ) and artemether-lumefantrine (AM-LM) therapy in young children from Papua New Guinea (PNG), there were no treatment failures in artemisinin-NQ-treated children with Plasmodium falciparum or Plasmodium vivax compared with 2.2% and 30.0%, respectively, in AM-LM-treated children during 42 days of follow-up. To determine whether, consistent with the long elimination half-life of NQ, this difference in efficacy would be more durable, clinical episodes of malaria were assessed in a subset of trial patients followed for six months post-treatment. METHODS For children completing trial procedures and who were assessable at six months, all within-trial and subsequent clinical malaria episodes were ascertained, the latter by clinic attendances and/or review of hand-held health records. Presentations with non-malarial illness were also recorded. Differences between allocated treatments for pre-specified endpoints were determined using Kaplan-Meier survival analysis. RESULTS Of 247 children who were followed to Day 42, 176 (71.3%) were included in the present sub-study, 87 allocated to AM-LM and 89 to artemisinin-NQ. Twenty children in the AM-LM group (32.8%) had a first episode of clinical malaria within six months compared with 10 (16.4%) in the artemisinin-NQ group (P = 0.033, log rank test). The median (interquartile range) time to first episode of clinical malaria was 64 (50-146) vs 116 (77-130) days, respectively (P = 0.20). There were no between-group differences in the incidence of first presentation with non-malarial illness (P = 0.31). CONCLUSIONS The greater effectiveness of artemisinin-NQ over conventional AM-LM extends to at least six months post-treatment for clinical malaria but not non-malarial illness. TRIAL REGISTRATION Australian New Zealand Clinical Trials Registry ACTRN12610000913077 .
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Affiliation(s)
- Moses Laman
- School of Medicine and Pharmacology, University of Western Australia, Fremantle Hospital, PO Box 480, Fremantle, 6959, WA, Australia. .,Papua New Guinea Institute of Medical Research, Madang, Papua New Guinea.
| | - John M Benjamin
- Papua New Guinea Institute of Medical Research, Madang, Papua New Guinea.
| | - Brioni R Moore
- School of Medicine and Pharmacology, University of Western Australia, Fremantle Hospital, PO Box 480, Fremantle, 6959, WA, Australia. .,Papua New Guinea Institute of Medical Research, Madang, Papua New Guinea.
| | - Mary Salib
- Papua New Guinea Institute of Medical Research, Madang, Papua New Guinea.
| | - Somoyang Tawat
- Papua New Guinea Institute of Medical Research, Madang, Papua New Guinea.
| | - Wendy A Davis
- School of Medicine and Pharmacology, University of Western Australia, Fremantle Hospital, PO Box 480, Fremantle, 6959, WA, Australia.
| | - Peter M Siba
- Papua New Guinea Institute of Medical Research, Madang, Papua New Guinea.
| | - Leanne J Robinson
- Papua New Guinea Institute of Medical Research, Madang, Papua New Guinea. .,Infection and Immunity Division, Walter and Eliza Hall Institute, Parkville, VIC, Australia. .,Department of Medical Biology, University of Melbourne, Melbourne, VIC, Australia.
| | - Timothy M E Davis
- School of Medicine and Pharmacology, University of Western Australia, Fremantle Hospital, PO Box 480, Fremantle, 6959, WA, Australia.
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Design and Synthesis of Novel Hybrid Molecules against Malaria. INTERNATIONAL JOURNAL OF MEDICINAL CHEMISTRY 2015; 2015:458319. [PMID: 25734014 PMCID: PMC4334980 DOI: 10.1155/2015/458319] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/08/2014] [Revised: 12/05/2014] [Accepted: 12/10/2014] [Indexed: 01/26/2023]
Abstract
The effective treatment of malaria can be very complex: Plasmodium parasites develop in multiple stages within a complex life cycle between mosquitoes as vectors and vertebrates as hosts. For the full and effective elimination of parasites, an effective drug should be active against the earliest stages of the Plasmodium infection: liver stages (reduce the progress of the infection), blood stages (cure the clinical symptoms), and gametocytes (inhibit the transmission cycle). Towards this goal, here we report the design, the synthetic methodology, and the characterization of novel hybrid agents with combined activity against Plasmodium liver stages and blood stages and gametocytes. The divergent synthetic approach allows the access to differently linked primaquine-chloroquine hybrid templates in up to eight steps.
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Read AF, Huijben S. Evolutionary biology and the avoidance of antimicrobial resistance. Evol Appl 2015; 2:40-51. [PMID: 25567846 PMCID: PMC3352414 DOI: 10.1111/j.1752-4571.2008.00066.x] [Citation(s) in RCA: 51] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2008] [Accepted: 12/11/2008] [Indexed: 11/29/2022] Open
Abstract
Evolutionary biologists have largely left the search for solutions to the drug resistance crisis to biomedical scientists, physicians, veterinarians and public health specialists. We believe this is because the vast majority of professional evolutionary biologists consider the evolutionary science of drug resistance to be conceptually uninteresting. Using malaria as case study, we argue that it is not. We review examples of evolutionary thinking that challenge various fallacies dominating antimalarial therapy, and discuss open problems that need evolutionary insight. These problems are unlikely to be resolved by biomedical scientists ungrounded in evolutionary biology. Involvement by evolutionary biologists in the science of drug resistance requires no intellectual compromises: the problems are as conceptually challenging as they are important.
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Affiliation(s)
- Andrew F Read
- Center for Infectious Disease Dynamics, Departments of Biology and Entomology, Pennsylvania State University, University Park PA, USA
| | - Silvie Huijben
- Center for Infectious Disease Dynamics, Departments of Biology and Entomology, Pennsylvania State University, University Park PA, USA ; School of Biological Sciences, University of Edinburgh West Mains Road, Edinburgh, UK
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Teboh-Ewungkem MI, Mohammed-Awel J, Baliraine FN, Duke-Sylvester SM. The effect of intermittent preventive treatment on anti-malarial drug resistance spread in areas with population movement. Malar J 2014; 13:428. [PMID: 25398463 PMCID: PMC4289180 DOI: 10.1186/1475-2875-13-428] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2014] [Accepted: 10/25/2014] [Indexed: 11/30/2022] Open
Abstract
Background The use of intermittent preventive treatment in pregnant women (IPTp), children (IPTc) and infant (IPTi) is an increasingly popular preventive strategy aimed at reducing malaria risk in these vulnerable groups. Studies to understand how this preventive intervention can affect the spread of anti-malarial drug resistance are important especially when there is human movement between neighbouring low and high transmission areas. Because the same drug is sometimes utilized for IPTi and for symptomatic malaria treatment, distinguishing their individual roles on accelerating the spread of drug resistant malaria, with or without human movement, may be difficult to isolate experimentally or by analysing data. A theoretical framework, as presented here, is thus relevant as the role of IPTi on accelerating the spread of drug resistance can be isolated in individual populations and when the populations are interconnected and interact. Methods A previously published model is expanded to include human movement between neighbouring high and low transmission areas, with focus placed on the malaria parasites. Parasite fitness functions, determined by how many humans the parasites can infect, are used to investigate how fast resistance can spread within the neighbouring communities linked by movement, when the populations are at endemic equilibrium. Results Model simulations indicate that population movement results in resistance spreading fastest in high transmission areas, and the more complete the anti-malarial resistance the faster the resistant parasite will tend to spread through a population. Moreover, the demography of infection in low transmission areas tends to change to reflect the demography of high transmission areas. Additionally, when regions are strongly connected the rate of spread of partially resistant parasites (R1) relative to drug sensitive parasites (RS), and fully resistant parasites (R2) relative to partially resistant parasites (R1) tend to behave the same in both populations, as should be expected. Conclusions In fighting anti-malarial drug resistance, different drug resistance monitoring and management policies are needed when the area in question is an isolated high or low transmission area, or when it is close and interacting with a neighbouring high or low transmission area, with human movement between them. Electronic supplementary material The online version of this article (doi:10.1186/1475-2875-13-428) contains supplementary material, which is available to authorized users.
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Evaluation of the quality of artemisinin-based antimalarial medicines distributed in ghana and togo. Malar Res Treat 2014; 2014:806416. [PMID: 25400975 PMCID: PMC4225840 DOI: 10.1155/2014/806416] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2014] [Revised: 09/26/2014] [Accepted: 09/29/2014] [Indexed: 12/18/2022] Open
Abstract
This study, conducted as part of our overall goal of regular pharmacovigilance of antimalarial medicines, reports on the quality of 132 artemisinin-based antimalarial medicines distributed in Ghana and Togo. Three methods were employed in the quality evaluation—basic (colorimetric) tests for establishing the identity of the requisite active pharmaceutical ingredients (APIs), semi-quantitative TLC assay for the identification and estimation of API content, and HPLC assay for a more accurate quantification of API content. From the basic tests, only one sample totally lacked API. The HPLC assay, however, showed that 83.7% of the ACTs and 57.9% of the artemisinin-based monotherapies failed to comply with international pharmacopoeia requirements due to insufficient API content. In most of the ACTs, the artemisinin component was usually the insufficient API. Generally, there was a good correlation between the HPLC and SQ-TLC assays. The overall failure rates for both locally manufactured (77.3%) and imported medicines (77.5%) were comparable. Similarly the unregistered medicines recorded a slightly higher overall failure rate (84.7%) than registered medicines (70.8%). Only two instances of possible cross-border exchange of medicines were observed and there was little difference between the medicine quality of collections from border towns and those from inland parts of both countries.
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Absence of the human CYP2C8*3 allele in Ugandan children exposed to Plasmodium falciparum malaria. INFECTION GENETICS AND EVOLUTION 2014; 27:432-5. [DOI: 10.1016/j.meegid.2014.08.011] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/20/2014] [Revised: 08/05/2014] [Accepted: 08/16/2014] [Indexed: 11/20/2022]
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Maganda BA, Minzi OMS, Kamuhabwa AAR, Ngasala B, Sasi PG. Outcome of artemether-lumefantrine treatment for uncomplicated malaria in HIV-infected adult patients on anti-retroviral therapy. Malar J 2014; 13:205. [PMID: 24885714 PMCID: PMC4051371 DOI: 10.1186/1475-2875-13-205] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2013] [Accepted: 05/23/2014] [Indexed: 01/24/2023] Open
Abstract
BACKGROUND Malaria and HIV infections are both highly prevalent in sub-Saharan Africa, with HIV-infected patients being at higher risks of acquiring malaria. The majority of antiretroviral (ART) and anti-malarial drugs are metabolized by the CYP450 system, creating a chance of drug-drug interaction upon co-administration. Limited data are available on the effectiveness of the artemether-lumefantrine combination (AL) when co-administered with non-nucleoside reverse transcriptase inhibitors (NNRTIs). The aim of this study was to compare anti-malarial treatment responses between HIV-1 infected patients on either nevirapine- or efavirenz-based treatment and those not yet on ART (control-arm) with uncomplicated falciparum malaria, treated with AL. METHOD This was a prospective, non-randomized, open-label study conducted in Bagamoyo district, with three arms of HIV-infected adults: efavirenz-based treatment arm (EFV-arm) n = 66, nevirapine-based treatment arm (NVP-arm) n = 128, and control-arm n = 75, with uncomplicated malaria. All patients were treated with AL and followed up for 28 days. The primary outcome measure was an adequate clinical and parasitological response (ACPR) after treatment with AL by day 28. RESULTS Day 28 ACPR was 97.6%, 82.5% and 94.5% for the NVP-arm, EFV-arm and control-arm, respectively. No early treatment or late parasitological failure was reported. The cumulative risk of recurrent parasitaemia was >19-fold higher in the EFV-arm than in the control-arm (Hazard ratio [HR], 19.11 [95% confidence interval {CI}, 10.5-34.5]; P < 0.01). The cumulative risk of recurrent parasitaemia in the NVP-arm was not significantly higher than in the control-arm ([HR], 2.44 [95% {CI}, 0.79-7.6]; P = 0.53). The median (IQR) day 7 plasma concentrations of lumefantrine for the three arms were: 1,125 ng/m (638.8-1913), 300.4 ng/ml (220.8-343.1) and 970 ng/ml (562.1-1729) for the NVP-arm, the EFV-arm and the control-arm, respectively (P < 0.001). In all three arms, the reported adverse events were mostly mild. CONCLUSION After 28 days of follow-up, AL was statistically safe and effective in the treatment of uncomplicated malaria in the NVP-arm. The results of this study also provide an indication of the possible impact of EFV on the performance of AL and the likelihood of it affecting uncomplicated falciparum malaria treatment outcome.
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Affiliation(s)
| | - Omary M S Minzi
- Unit of Pharmacology and Therapeutics, School of Pharmacy, Muhimbili University of Health and Allied Sciences, P,O, BOX 65013, Dar es Salaam, Tanzania.
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Wanzira H, Kakuru A, Arinaitwe E, Bigira V, Muhindo MK, Conrad M, Rosenthal PJ, Kamya MR, Tappero JW, Dorsey G. Longitudinal outcomes in a cohort of Ugandan children randomized to artemether-lumefantrine versus dihydroartemisinin-piperaquine for the treatment of malaria. Clin Infect Dis 2014; 59:509-16. [PMID: 24825870 DOI: 10.1093/cid/ciu353] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
BACKGROUND Artemisinin-based combination therapy (ACT) has become the standard of care for the treatment of uncomplicated Plasmodium falciparum malaria. Although several ACT regimens are approved, data guiding optimal choices of ACTs are limited. We compared short- and long-term outcomes in a cohort of young Ugandan children randomized to 2 leading ACTs. METHODS Overall, 312 children were randomized to artemether-lumefantrine or dihydroartemisinin-piperaquine (DP) at the time of the first episode of uncomplicated malaria (median age, 10.5 months). The same treatment was given for all subsequent episodes of uncomplicated malaria and children were followed until they reached 5 years of age. The cohort included a subgroup that was human immunodeficiency virus (HIV) infected (n = 44) or HIV exposed (n = 175) and prescribed trimethoprim-sulfamethoxazole (TMP-SMX) prophylaxis. Outcomes included time to recurrent malaria following individual treatments and the overall incidences of treatments for malaria, complicated malaria, and hospitalizations. RESULTS Among children not prescribed TMP-SMX prophylaxis, 4443 treatments for malaria were given over 790 person-years following randomization. Treatment with DP was associated with a lower hazard of recurrent malaria over the 84 days after treatment (hazard ratio, 0.66; 95% confidence interval [CI], .61-.70; P < .001). Children randomized to DP had a lower incidence of all treatments for malaria (incidence rate ratio [IRR], 0.85; 95% CI, .75-.96; P = .01), complicated malaria (IRR, 0.12; 95% CI, .04-.39; P < .001), and hospitalizations (IRR, 0.31; 95% CI, .13-.77; P = .01). Among children prescribed TMP-SMX prophylaxis, there were no significant differences in longitudinal outcomes. CONCLUSIONS Compared to artemether-lumefantrine, the use of DP to treat uncomplicated malaria delayed the time to recurrent malaria and reduced the incidences of treatments for malaria, complicated malaria, and hospitalizations. CLINICAL TRIALS REGISTRATION NCT00527800.
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Affiliation(s)
| | - Abel Kakuru
- Infectious Diseases Research Collaboration, Kampala, Uganda
| | | | - Victor Bigira
- Infectious Diseases Research Collaboration, Kampala, Uganda
| | - Mary K Muhindo
- Infectious Diseases Research Collaboration, Kampala, Uganda
| | - Melissa Conrad
- Department of Medicine, University of California, San Francisco
| | | | - Moses R Kamya
- Department of Medicine, Makerere University College of Health Sciences, Kampala, Uganda
| | - Jordan W Tappero
- Center for Global Health, Centers for Disease Control and Prevention, Atlanta, Georgia
| | - Grant Dorsey
- Department of Medicine, University of California, San Francisco
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Pollitt LC, Huijben S, Sim DG, Salathé RM, Jones MJ, Read AF. Rapid response to selection, competitive release and increased transmission potential of artesunate-selected Plasmodium chabaudi malaria parasites. PLoS Pathog 2014; 10:e1004019. [PMID: 24763470 PMCID: PMC3999151 DOI: 10.1371/journal.ppat.1004019] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2013] [Accepted: 02/06/2014] [Indexed: 11/19/2022] Open
Abstract
The evolution of drug resistance, a key challenge for our ability to treat and control infections, depends on two processes: de-novo resistance mutations, and the selection for and spread of resistant mutants within a population. Understanding the factors influencing the rates of these two processes is essential for maximizing the useful lifespan of drugs and, therefore, effective disease control. For malaria parasites, artemisinin-based drugs are the frontline weapons in the fight against disease, but reports from the field of slower parasite clearance rates during drug treatment are generating concern that the useful lifespan of these drugs may be limited. Whether slower clearance rates represent true resistance, and how this provides a selective advantage for parasites is uncertain. Here, we show that Plasmodium chabaudi malaria parasites selected for resistance to artesunate (an artemisinin derivative) through a step-wise increase in drug dose evolved slower clearance rates extremely rapidly. In single infections, these slower clearance rates, similar to those seen in the field, provided fitness advantages to the parasite through increased overall density, recrudescence after treatment and increased transmission potential. In mixed infections, removal of susceptible parasites by drug treatment led to substantial increases in the densities and transmission potential of resistant parasites (competitive release). Our results demonstrate the double-edged sword for resistance management: in our initial selection experiments, no parasites survived aggressive chemotherapy, but after selection, the fitness advantage for resistant parasites was greatest at high drug doses. Aggressive treatment of mixed infections resulted in resistant parasites dominating the pool of gametocytes, without providing additional health benefits to hosts. Slower clearance rates can evolve rapidly and can provide a strong fitness advantage during drug treatment in both single and mixed strain infections.
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Affiliation(s)
- Laura C. Pollitt
- Center for Infectious Disease Dynamics, Department of Biology, Pennsylvania State University, University Park, Pennsylvania, United States of America
- Centre for Immunology, Infection and Evolution, The University of Edinburgh, Edinburgh, United Kingdom
- * E-mail:
| | - Silvie Huijben
- Center for Infectious Disease Dynamics, Department of Biology, Pennsylvania State University, University Park, Pennsylvania, United States of America
| | - Derek G. Sim
- Center for Infectious Disease Dynamics, Department of Biology, Pennsylvania State University, University Park, Pennsylvania, United States of America
| | - Rahel M. Salathé
- Center for Infectious Disease Dynamics, Department of Biology, Pennsylvania State University, University Park, Pennsylvania, United States of America
| | - Matthew J. Jones
- Center for Infectious Disease Dynamics, Department of Biology, Pennsylvania State University, University Park, Pennsylvania, United States of America
| | - Andrew F. Read
- Center for Infectious Disease Dynamics, Department of Biology, Pennsylvania State University, University Park, Pennsylvania, United States of America
- Department of Entomology, The Pennsylvania State University, University Park, Pennsylvania, United States of America
- Fogarty International Center, National Institutes of Health, Bethesda, Maryland, United States of America
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Pfeil J, Borrmann S, Tozan Y. Dihydroartemisinin-piperaquine vs. artemether-lumefantrine for first-line treatment of uncomplicated malaria in African children: a cost-effectiveness analysis. PLoS One 2014; 9:e95681. [PMID: 24748395 PMCID: PMC3991722 DOI: 10.1371/journal.pone.0095681] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2013] [Accepted: 03/31/2014] [Indexed: 12/31/2022] Open
Abstract
Background Recent multi-centre trials showed that dihydroartemisinin-piperaquine (DP) was as efficacious and safe as artemether-lumefantrine (AL) for treatment of young children with uncomplicated P. falciparum malaria across diverse transmission settings in Africa. Longitudinal follow-up of patients in these trials supported previous findings that DP had a longer post-treatment prophylactic effect than AL, reducing the risk of reinfection and conferring additional health benefits to patients, particularly in areas with moderate to high malaria transmission. Methods We developed a Markov model to assess the cost-effectiveness of DP versus AL for first-line treatment of uncomplicated malaria in young children from the provider perspective, taking into consideration the post-treatment prophylactic effects of the drugs as reported by a recent multi-centre trial in Africa and using the maximum manufacturer drug prices for artemisinin-based combination therapies set by the Global Fund in 2013. We estimated the price per course of treatment threshold above which DP would cease to be a cost-saving alternative to AL as a first-line antimalarial drug. Results First-line treatment with DP compared to AL averted 0.03 DALYs (95% CI: 0.006–0.07) and 0.001 deaths (95% CI: 0.00–0.002) and saved $0.96 (95% CI: 0.33–2.46) per child over one year. The results of the threshold analysis showed that DP remained cost-saving over AL for any DP cost below $1.23 per course of treatment. Conclusions DP is superior to AL from both the clinical and economic perspectives for treatment of uncomplicated P. falciparum malaria in young children. A paediatric dispersible formulation of DP is under development and should facilitate a targeted deployment of this antimalarial drug. The use of DP as first-line antimalarial drug in paediatric malaria patients in moderate to high transmission areas of Africa merits serious consideration by health policymakers.
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Affiliation(s)
- Johannes Pfeil
- Centre for Childhood and Adolescent Medicine and Department of Infectious Diseases, University Hospital, Heidelberg, Germany
- German Centre for Infection Research (DZIF), Heidelberg, Germany
| | - Steffen Borrmann
- Kenyan Medical Research Institute (KEMRI), Kilifi, Kenya
- Institute of Tropical Medicine, University of Tübingen, Tübingen, Germany
| | - Yeşim Tozan
- Steinhardt School of Culture, Education and Human Development, New York University, New York, New York, United States of America
- Institute of Public Health, Ruprecht-Karls-University, Heidelberg, Germany
- * E-mail:
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Pfeil J, Borrmann S, Tozan Y. Dihydroartemisinin-piperaquine vs. artemether-lumefantrine for first-line treatment of uncomplicated malaria in African children: a cost-effectiveness analysis. PLoS One 2014. [PMID: 24748395 DOI: 10.1371/journal.pone.0095681.ecollection] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022] Open
Abstract
BACKGROUND Recent multi-centre trials showed that dihydroartemisinin-piperaquine (DP) was as efficacious and safe as artemether-lumefantrine (AL) for treatment of young children with uncomplicated P. falciparum malaria across diverse transmission settings in Africa. Longitudinal follow-up of patients in these trials supported previous findings that DP had a longer post-treatment prophylactic effect than AL, reducing the risk of reinfection and conferring additional health benefits to patients, particularly in areas with moderate to high malaria transmission. METHODS We developed a Markov model to assess the cost-effectiveness of DP versus AL for first-line treatment of uncomplicated malaria in young children from the provider perspective, taking into consideration the post-treatment prophylactic effects of the drugs as reported by a recent multi-centre trial in Africa and using the maximum manufacturer drug prices for artemisinin-based combination therapies set by the Global Fund in 2013. We estimated the price per course of treatment threshold above which DP would cease to be a cost-saving alternative to AL as a first-line antimalarial drug. RESULTS First-line treatment with DP compared to AL averted 0.03 DALYs (95% CI: 0.006-0.07) and 0.001 deaths (95% CI: 0.00-0.002) and saved $0.96 (95% CI: 0.33-2.46) per child over one year. The results of the threshold analysis showed that DP remained cost-saving over AL for any DP cost below $1.23 per course of treatment. CONCLUSIONS DP is superior to AL from both the clinical and economic perspectives for treatment of uncomplicated P. falciparum malaria in young children. A paediatric dispersible formulation of DP is under development and should facilitate a targeted deployment of this antimalarial drug. The use of DP as first-line antimalarial drug in paediatric malaria patients in moderate to high transmission areas of Africa merits serious consideration by health policymakers.
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Affiliation(s)
- Johannes Pfeil
- Centre for Childhood and Adolescent Medicine and Department of Infectious Diseases, University Hospital, Heidelberg, Germany; German Centre for Infection Research (DZIF), Heidelberg, Germany
| | - Steffen Borrmann
- Kenyan Medical Research Institute (KEMRI), Kilifi, Kenya; Institute of Tropical Medicine, University of Tübingen, Tübingen, Germany
| | - Yeşim Tozan
- Steinhardt School of Culture, Education and Human Development, New York University, New York, New York, United States of America; Institute of Public Health, Ruprecht-Karls-University, Heidelberg, Germany
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Grobler L, Grobler A, Haynes R, Masimirembwa C, Thelingwani R, Steenkamp P, Steyn HS. The effect of the Pheroid delivery system on the in vitro metabolism and in vivo pharmacokinetics of artemisone. Expert Opin Drug Metab Toxicol 2014; 10:313-25. [PMID: 24511903 DOI: 10.1517/17425255.2014.885503] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
OBJECTIVES The objectives were to determine the pharmacokinetics (PK) of artemisone and artemisone formulated in the Pheroid® drug delivery system in primates and to establish whether the formulation affects the in vitro metabolism of artemisone in human and monkey liver and intestinal microsomes. METHODS For the PK study, a single oral dose of artemisone was administered to vervet monkeys using a crossover design. Plasma samples were analyzed by means of liquid chromatography-tandem mass spectrometry. For the in vitro metabolism study, clearance was determined using microsomes and recombinant CYP3A4 enzymes, and samples were analyzed by means of ultra-performance liquid chromatography quadrupole time-of-flight mass spectrometry. RESULTS Artemisone and M1 plasma levels were unexpectedly low compared to those previously recorded in rodents and humans. The in vitro intrinsic clearance (CLint) of the reference formulation with monkey liver microsomes was much higher (1359.33 ± 103.24 vs 178.86 ± 23.42) than that of human liver microsomes. The in vitro data suggest that microsomal metabolism of artemisone is inhibited by the Pheroid delivery system. CONCLUSIONS The in vivo results obtained in this study indicate that the Pheroid delivery system improves the PK profile of artemisone. The in vitro results indicate that microsomal metabolism of artemisone is inhibited by the Pheroid delivery system.
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Affiliation(s)
- Lizette Grobler
- North-West University, Faculty of Health Sciences, DST/NWU Preclinical Drug Development Platform , Potchefstroom , South Africa +27 18 299 2281, +27 18 299 4467 ; +27 18 285 2233 ; ;
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Gosling RD, Cairns ME, Chico RM, Chandramohan D. Intermittent preventive treatment against malaria: an update. Expert Rev Anti Infect Ther 2014; 8:589-606. [DOI: 10.1586/eri.10.36] [Citation(s) in RCA: 52] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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Plasmodium falciparum Polymorphisms associated with ex vivo drug susceptibility and clinical effectiveness of artemisinin-based combination therapies in Benin. Antimicrob Agents Chemother 2013; 58:1-10. [PMID: 24100489 DOI: 10.1128/aac.01790-12] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023] Open
Abstract
Artemisinin-based combination therapies (ACTs) are the main option to treat malaria, and their efficacy and susceptibility must be closely monitored to avoid resistance. We assessed the association of Plasmodium falciparum polymorphisms and ex vivo drug susceptibility with clinical effectiveness. Patients enrolled in an effectiveness trial comparing artemether-lumefantrine (n = 96), fixed-dose artesunate-amodiaquine (n = 96), and sulfadoxine-pyrimethamine (n = 48) for the treatment of uncomplicated malaria 2007 in Benin were assessed. pfcrt, pfmdr1, pfmrp1, pfdhfr, and pfdhps polymorphisms were analyzed pretreatment and in recurrent infections. Drug susceptibility was determined in fresh baseline isolates by Plasmodium lactate dehydrogenase enzyme-linked immunosorbent assay (ELISA). A majority had 50% inhibitory concentration (IC50) estimates (the concentration required for 50% growth inhibition) lower than those of the 3D7 reference clone for desethylamodiaquine, lumefantrine, mefloquine, and quinine and was considered to be susceptible, while dihydroartemisinin and pyrimethamine IC50s were higher. No association was found between susceptibility to the ACT compounds and treatment outcome. Selection was observed for the pfmdr1 N86 allele in artemether-lumefantrine recrudescences (recurring infections) (4/7 [57.1%] versus 36/195 [18.5%]), and of the opposite allele, 86Y, in artesunate-amodiaquine reinfections (new infections) (20/22 [90.9%] versus 137/195 [70.3%]) compared to baseline infections. The importance of pfmdr1 N86 in lumefantrine tolerance was emphasized by its association with elevated lumefantrine IC50s. Genetic linkage between N86 and Y184 was observed, which together with the low frequency of 1246Y may explain regional differences in selection of pfmdr1 loci. Selection of opposite alleles in artemether-lumefantrine and artesunate-amodiaquine recurrent infections supports the strategy of multiple first-line treatment. Surveillance based on clinical, ex vivo, molecular, and pharmacological data is warranted.
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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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Opinion: the pharmacometrics of infectious disease. CPT-PHARMACOMETRICS & SYSTEMS PHARMACOLOGY 2013; 2:e70. [PMID: 23985968 PMCID: PMC3828010 DOI: 10.1038/psp.2013.46] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Received: 03/29/2013] [Accepted: 07/08/2013] [Indexed: 12/28/2022]
Abstract
The application of pharmacometric principles to the treatment of infectious diseases must address important biological issues across the diversity of pathogenic organisms. Recent applications of pharmacometric tools in this therapeutic area have had important translational impact not only in drug development but on real-world clinical practice. The fruitful fusion of preclinical and population methodologies promises increasingly personalized and mechanistic approaches.CPT: Pharmacometrics & Systems Pharmacology (2013) 2, e70; doi:10.1038/psp.2013.46; published online 28 August 2013.
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Kay K, Hastings IM. Improving pharmacokinetic-pharmacodynamic modeling to investigate anti-infective chemotherapy with application to the current generation of antimalarial drugs. PLoS Comput Biol 2013; 9:e1003151. [PMID: 23874190 PMCID: PMC3715401 DOI: 10.1371/journal.pcbi.1003151] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2012] [Accepted: 06/07/2013] [Indexed: 01/13/2023] Open
Abstract
Mechanism-based pharmacokinetic-pharmacodynamic (PK/PD) modelling is the standard computational technique for simulating drug treatment of infectious diseases with the potential to enhance our understanding of drug treatment outcomes, drug deployment strategies, and dosing regimens. Standard methodologies assume only a single drug is used, it acts only in its unconverted form, and that oral drugs are instantaneously absorbed across the gut wall to their site of action. For drugs with short half-lives, this absorption period accounts for a significant period of their time in the body. Treatment of infectious diseases often uses combination therapies, so we refined and substantially extended the PK/PD methodologies to incorporate (i) time lags and drug concentration profiles resulting from absorption across the gut wall and, if required, conversion to another active form; (ii) multiple drugs within a treatment combination; (iii) differing modes of action of drugs in the combination: additive, synergistic, antagonistic; (iv) drugs converted to an active metabolite with a similar mode of action. This methodology was applied to a case study of two first-line malaria treatments based on artemisinin combination therapies (ACTs, artemether-lumefantrine and artesunate-mefloquine) where the likelihood of increased artemisinin tolerance/resistance has led to speculation on their continued long-term effectiveness. We note previous estimates of artemisinin kill rate were underestimated by a factor of seven, both the unconverted and converted form of the artemisinins kill parasites and the extended PK/PD methodology produced results consistent with field observations. The simulations predict that a potentially rapid decline in ACT effectiveness is likely to occur as artemisinin resistance spreads, emphasising the importance of containing the spread of artemisinin resistance before it results in widespread drug failure. We found that PK/PD data is generally very poorly reported in the malaria literature, severely reducing its value for subsequent re-application, and we make specific recommendations to improve this situation.
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Affiliation(s)
- Katherine Kay
- Parasitology Department, Liverpool School of Tropical Medicine, Pembroke Place, Liverpool, United Kingdom.
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Burrows JN, van Huijsduijnen RH, Möhrle JJ, Oeuvray C, Wells TNC. Designing the next generation of medicines for malaria control and eradication. Malar J 2013; 12:187. [PMID: 23742293 PMCID: PMC3685552 DOI: 10.1186/1475-2875-12-187] [Citation(s) in RCA: 207] [Impact Index Per Article: 18.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2013] [Accepted: 05/29/2013] [Indexed: 11/10/2022] Open
Abstract
In the fight against malaria new medicines are an essential weapon. For the parts of the world where the current gold standard artemisinin combination therapies are active, significant improvements can still be made: for example combination medicines which allow for single dose regimens, cheaper, safer and more effective medicines, or improved stability under field conditions. For those parts of the world where the existing combinations show less than optimal activity, the priority is to have activity against emerging resistant strains, and other criteria take a secondary role. For new medicines to be optimal in malaria control they must also be able to reduce transmission and prevent relapse of dormant forms: additional constraints on a combination medicine. In the absence of a highly effective vaccine, new medicines are also needed to protect patient populations. In this paper, an outline definition of the ideal and minimally acceptable characteristics of the types of clinical candidate molecule which are needed (target candidate profiles) is suggested. In addition, the optimal and minimally acceptable characteristics of combination medicines are outlined (target product profiles). MMV presents now a suggested framework for combining the new candidates to produce the new medicines. Sustained investment over the next decade in discovery and development of new molecules is essential to enable the long-term delivery of the medicines needed to combat malaria.
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Affiliation(s)
- Jeremy N Burrows
- Medicines for Malaria Venture-MMV, PO Box 1826, Route de Pré-Bois 20, Geneva 151215, Switzerland
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Mwebaza N, Jerling M, Gustafsson LL, Obua C, Waako P, Mahindi M, Ntale M, Beck O, Hellgren U. Comparable Lumefantrine Oral Bioavailability when Co-administered With Oil-Fortified Maize Porridge or Milk in Healthy Volunteers. Basic Clin Pharmacol Toxicol 2013; 113:66-72. [DOI: 10.1111/bcpt.12065] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2012] [Accepted: 02/13/2013] [Indexed: 11/29/2022]
Affiliation(s)
| | - Markus Jerling
- Department of Laboratory Medicine; Division of Clinical Pharmacology; Karolinska Institutet; Stockholm; Sweden
| | - Lars L. Gustafsson
- Department of Laboratory Medicine; Division of Clinical Pharmacology; Karolinska Institutet; Stockholm; Sweden
| | - Celestino Obua
- Department of Pharmacology and Therapeutics; School of Biomedical Sciences; Makerere University College of Health Sciences; Kampala; Uganda
| | - Paul Waako
- Department of Pharmacology and Therapeutics; School of Biomedical Sciences; Makerere University College of Health Sciences; Kampala; Uganda
| | - Margarita Mahindi
- Department of Laboratory Medicine; Division of Clinical Pharmacology; Karolinska Institutet; Stockholm; Sweden
| | - Muhammad Ntale
- Department of Chemistry; College of Natural Sciences; Makerere University; Kampala; Uganda
| | - Olof Beck
- Department of Laboratory Medicine; Division of Clinical Pharmacology; Karolinska Institutet; Stockholm; Sweden
| | - Urban Hellgren
- Department of Medicine; Division of Infectious Diseases; Karolinska Institutet; Stockholm; Sweden
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50
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Sawa P, Shekalaghe SA, Drakeley CJ, Sutherland CJ, Mweresa CK, Baidjoe AY, Manjurano A, Kavishe RA, Beshir KB, Yussuf RU, Omar SA, Hermsen CC, Okell L, Schallig HDFH, Sauerwein RW, Hallett RL, Bousema T. Malaria transmission after artemether-lumefantrine and dihydroartemisinin-piperaquine: a randomized trial. J Infect Dis 2013; 207:1637-45. [PMID: 23468056 DOI: 10.1093/infdis/jit077] [Citation(s) in RCA: 90] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023] Open
Abstract
BACKGROUND Artemisinin-based combination therapy (ACT) reduces the potential for malaria transmission, compared with non-ACTs. It is unclear whether this effect differs between ACTs. METHODS A total of 298 children (age, 6 months to 10 years) with uncomplicated falciparum malaria were randomized to artemether-lumefantrine (AL; n = 153) or dihydroartemisinin-piperaquine (DP; n = 145) in Mbita, a community in western Kenya. Gametocyte carriage was determined by molecular methods on days 0, 1, 2, 3, 7, 14, 28, and 42 after treatment initiation. The gametocyte infectiousness to mosquitoes was determined by mosquito-feeding assays on day 7 after beginning therapy. RESULTS The cumulative risk of recurrent parasitemia on day 42 after initiation of treatment, unadjusted by polymerase chain reaction findings, was 20.7% (95% confidence interval [CI], 14.4-28.2) for AL, compared with 3.7% (95% CI, 1.2-8.5) for DP (P < .001). The mean duration of gametocyte carriage was 5.5 days (95% CI, 3.6-8.5) for AL and 15.3 days (95% CI, 9.7-24.2) for DP (P = .001). The proportion of mosquitoes that became infected after feeding on blood from AL-treated children was 1.88% (43 of 2293), compared with 3.50% (83 of 2371) for those that fed on blood from DP-treated children (P = .06); the oocyst burden among mosquitoes was lower among those that fed on blood from AL-treated children (P = .005) CONCLUSIONS: While DP was associated with a longer prophylactic time after treatment, gametocyte carriage and malaria transmission to mosquitoes was lower after AL treatment. CLINICAL TRIALS REGISTRATION NCT00868465.
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Affiliation(s)
- Patrick Sawa
- Human Health Division, International Centre for Insect Physiology and Ecology, Mbita Point, Nairobi, Kenya
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