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Talarico F, Chakravarty S, Liu YS, Greenshaw AJ, Passos IC, Cao B. Systematic Review of Psychiatric Adverse Effects Induced by Chloroquine and Hydroxychloroquine: Case Reports and Population Studies. Ann Pharmacother 2023; 57:463-479. [PMID: 35927939 DOI: 10.1177/10600280221113572] [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] [Indexed: 11/17/2022] Open
Abstract
OBJECTIVE To perform a systematic review on the psychiatric adverse effects of chloroquine (CQ) and hydroxychloroquine (HCQ); to summarize what is known about psychiatric adverse effects of these drugs; to compare clinical trials, populational studies, and case report studies; and to increase awareness of the potential psychiatric adverse effects of these drugs. DATA SOURCES A literature search of PubMed, Scopus, and Web of Science was performed to identify manuscripts published between December 1962 and June 2022. Search terms included CQ, HCQ, psychiatry, psychosis, depression, anxiety, bipolar disorder, delirium, and psychotic disorders. STUDY SELECTION AND DATA EXTRACTION Relevant studies included reports of adverse effects after CQ or HCQ ingestion. DATA SYNTHESIS The current literature presents evidence for a risk of short-term psychiatric adverse effects induced by either CQ or HCQ. However, the populational-level studies presented some limitations regarding the voluntary response in survey data, self-report adverse effects, and placebo group reporting similar symptoms to the case group. Thus, populational-level studies addressing the discussed limitations and the nature and extent of possible psychiatric adverse effects are needed. RELEVANCE TO PATIENT CARE AND CLINICAL PRACTICE Most of the patients who developed such adverse effects did not report a family history of psychiatric disease. The frequency of psychiatric adverse effects depends on the patient's biological sex, age, and body mass index, but not on the drug dosage. CONCLUSIONS Based on clinical trials and case reports, the current literature presents evidence for a risk of short-term psychiatric adverse effects induced by either drug.
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Affiliation(s)
- Fernanda Talarico
- Department of Psychiatry, University of Alberta, Edmonton, AB, Canada
| | | | - Yang S Liu
- Department of Psychiatry, University of Alberta, Edmonton, AB, Canada
| | | | - Ives Cavalcante Passos
- Programa de Pós-Graduação em Psiquiatria e Ciências do Comportamento, Laboratory of Molecular Psychiatry and Bipolar Disorder Program, Hospital de Clínicas de Porto Alegre, Universidade Federal do Rio Grande do Sul, Porto Alegre, RS, Brazil
| | - Bo Cao
- Department of Psychiatry, University of Alberta, Edmonton, AB, Canada
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Kalkman LC, Hanscheid T, Krishna S, Kremsner PG, Grobusch MP. Antimalarial treatment in infants. Expert Opin Pharmacother 2022; 23:1711-1726. [PMID: 36174125 DOI: 10.1080/14656566.2022.2130687] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022]
Abstract
INTRODUCTION Malaria in infants is common in high-transmission settings, especially in infants >6 months. Infants undergo physiological changes impacting pharmacokinetics and pharmacodynamics of anti-malarial drugs and, consequently, the safety and efficacy of malaria treatment. Yet, treatment guidelines and evidence on pharmacological interventions for malaria often fail to address this vulnerable age-group. This review aims to summarise the available data on anti-malarial treatment in infants. AREAS COVERED The standard recommended treatments for severe and uncomplicated malaria are generally safe and effective in infants. However, infants have an increased risk of drug-related vomiting and have distinct pharmacokinetic parameters of antimalarials compared with older patients. These include larger volumes of distribution, higher clearance rates and immature enzyme systems. Consequently, infants with malaria may be at increased risk of treatment failure and drug toxicity. EXPERT OPINION Knowledge expansion to optimize treatment can be achieved by including more infants in antimalarial drug trials and by reporting separately on treatment outcomes in infants. Additional evidence on the efficacy, safety, tolerability, acceptability and effectiveness of ACTs in infants is needed, as well as population pharmacokinetics studies on antimalarials in the infant population.
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Affiliation(s)
- Laura C Kalkman
- Center of Tropical Medicine and Travel Medicine, Department of Infectious Diseases, Amsterdam University Medical Centers, location Amsterdam, Amsterdam Infection & Immunity, Amsterdam Public Health, University of Amsterdam, Amsterdam, The Netherlands
| | - Thomas Hanscheid
- Instituto de Microbiologia, Faculdade de Medicina, Universidade de Lisboa, Lisbon, Portugal
| | - Sanjeev Krishna
- Institut für Tropenmedizin, Eberhard Karls Universität Tübingen, and German Center for Infection Research (DZIF), Tübingen, Germany.,Centre de Recherches Médicales de Lambaréné (CERMEL), Lambaréné, Gabon.,Clinical Academic Group, Institute for Infection and Immunity, and St. George's University Hospitals NHS Foundation Trust, St. George's University of London, London, UK
| | - Peter G Kremsner
- Institut für Tropenmedizin, Eberhard Karls Universität Tübingen, and German Center for Infection Research (DZIF), Tübingen, Germany.,Centre de Recherches Médicales de Lambaréné (CERMEL), Lambaréné, Gabon
| | - Martin P Grobusch
- Center of Tropical Medicine and Travel Medicine, Department of Infectious Diseases, Amsterdam University Medical Centers, location Amsterdam, Amsterdam Infection & Immunity, Amsterdam Public Health, University of Amsterdam, Amsterdam, The Netherlands.,Institut für Tropenmedizin, Eberhard Karls Universität Tübingen, and German Center for Infection Research (DZIF), Tübingen, Germany.,Centre de Recherches Médicales de Lambaréné (CERMEL), Lambaréné, Gabon.,Institute of Infectious Diseases and Molecular Medicine, University of Cape Town, Cape Town, South Africa.,Masanga Medical Research Unit (MMRU), Masanga, Sierra Leone
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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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Mansoor R, Commons RJ, Douglas NM, Abuaku B, Achan J, Adam I, Adjei GO, Adjuik M, Alemayehu BH, Allan R, Allen EN, Anvikar AR, Arinaitwe E, Ashley EA, Ashurst H, Asih PBS, Bakyaita N, Barennes H, Barnes KI, Basco L, Bassat Q, Baudin E, Bell DJ, Bethell D, Bjorkman A, Boulton C, Bousema T, Brasseur P, Bukirwa H, Burrow R, Carrara VI, Cot M, D’Alessandro U, Das D, Das S, Davis TME, Desai M, Djimde AA, Dondorp AM, Dorsey G, Drakeley CJ, Duparc S, Espié E, Etard JF, Falade C, Faucher JF, Filler S, Fogg C, Fukuda M, Gaye O, Genton B, Ghulam Rahim A, Gilayeneh J, Gonzalez R, Grais RF, Grandesso F, Greenwood B, Grivoyannis A, Hatz C, Hodel EM, Humphreys GS, Hwang J, Ishengoma D, Juma E, Kachur SP, Kager PA, Kamugisha E, Kamya MR, Karema C, Kayentao K, Kazienga A, Kiechel JR, Kofoed PE, Koram K, Kremsner PG, Lalloo DG, Laman M, Lee SJ, Lell B, Maiga AW, Mårtensson A, Mayxay M, Mbacham W, McGready R, Menan H, Ménard D, Mockenhaupt F, Moore BR, Müller O, Nahum A, Ndiaye JL, Newton PN, Ngasala BE, Nikiema F, Nji AM, Noedl H, Nosten F, Ogutu BR, Ojurongbe O, Osorio L, Ouédraogo JB, Owusu-Agyei S, Pareek A, Penali LK, Piola P, Plucinski M, Premji Z, Ramharter M, Richmond CL, Rombo L, Roper C, Rosenthal PJ, Salman S, Same-Ekobo A, Sibley C, Sirima SB, Smithuis FM, Somé FA, Staedke SG, Starzengruber P, Strub-Wourgaft N, Sutanto I, Swarthout TD, Syafruddin D, Talisuna AO, Taylor WR, Temu EA, Thwing JI, Tinto H, Tjitra E, Touré OA, Tran TH, Ursing J, Valea I, Valentini G, van Vugt M, von Seidlein L, Ward SA, Were V, White NJ, Woodrow CJ, Yavo W, Yeka A, Zongo I, Simpson JA, Guerin PJ, Stepniewska K, Price RN. Haematological consequences of acute uncomplicated falciparum malaria: a WorldWide Antimalarial Resistance Network pooled analysis of individual patient data. BMC Med 2022; 20:85. [PMID: 35249546 PMCID: PMC8900374 DOI: 10.1186/s12916-022-02265-9] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/01/2021] [Accepted: 01/18/2022] [Indexed: 01/13/2023] Open
Abstract
BACKGROUND Plasmodium falciparum malaria is associated with anaemia-related morbidity, attributable to host, parasite and drug factors. We quantified the haematological response following treatment of uncomplicated P. falciparum malaria to identify the factors associated with malarial anaemia. METHODS Individual patient data from eligible antimalarial efficacy studies of uncomplicated P. falciparum malaria, available through the WorldWide Antimalarial Resistance Network data repository prior to August 2015, were pooled using standardised methodology. The haematological response over time was quantified using a multivariable linear mixed effects model with nonlinear terms for time, and the model was then used to estimate the mean haemoglobin at day of nadir and day 7. Multivariable logistic regression quantified risk factors for moderately severe anaemia (haemoglobin < 7 g/dL) at day 0, day 3 and day 7 as well as a fractional fall ≥ 25% at day 3 and day 7. RESULTS A total of 70,226 patients, recruited into 200 studies between 1991 and 2013, were included in the analysis: 50,859 (72.4%) enrolled in Africa, 18,451 (26.3%) in Asia and 916 (1.3%) in South America. The median haemoglobin concentration at presentation was 9.9 g/dL (range 5.0-19.7 g/dL) in Africa, 11.6 g/dL (range 5.0-20.0 g/dL) in Asia and 12.3 g/dL (range 6.9-17.9 g/dL) in South America. Moderately severe anaemia (Hb < 7g/dl) was present in 8.4% (4284/50,859) of patients from Africa, 3.3% (606/18,451) from Asia and 0.1% (1/916) from South America. The nadir haemoglobin occurred on day 2 post treatment with a mean fall from baseline of 0.57 g/dL in Africa and 1.13 g/dL in Asia. Independent risk factors for moderately severe anaemia on day 7, in both Africa and Asia, included moderately severe anaemia at baseline (adjusted odds ratio (AOR) = 16.10 and AOR = 23.00, respectively), young age (age < 1 compared to ≥ 12 years AOR = 12.81 and AOR = 6.79, respectively), high parasitaemia (AOR = 1.78 and AOR = 1.58, respectively) and delayed parasite clearance (AOR = 2.44 and AOR = 2.59, respectively). In Asia, patients treated with an artemisinin-based regimen were at significantly greater risk of moderately severe anaemia on day 7 compared to those treated with a non-artemisinin-based regimen (AOR = 2.06 [95%CI 1.39-3.05], p < 0.001). CONCLUSIONS In patients with uncomplicated P. falciparum malaria, the nadir haemoglobin occurs 2 days after starting treatment. Although artemisinin-based treatments increase the rate of parasite clearance, in Asia they are associated with a greater risk of anaemia during recovery.
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Ursing J, Johns R, Aydin-Schmidt B, Calçada C, Kofoed PE, Ghanchi NK, Veiga MI, Rombo L. OUP accepted manuscript. J Antimicrob Chemother 2022; 77:1005-1011. [PMID: 35137072 PMCID: PMC8969533 DOI: 10.1093/jac/dkac008] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2021] [Accepted: 12/24/2021] [Indexed: 11/14/2022] Open
Abstract
Background Plasmodium falciparum strains that are resistant to standard-dose chloroquine can be treated by higher chloroquine concentrations maintained for a longer time in vivo. Objectives To determine the relative importance of chloroquine concentrations versus exposure time for elimination of chloroquine-susceptible and -resistant P. falciparum in vitro. Methods Chloroquine-susceptible (3D7) and -resistant (FCR3) strains were exposed in vitro to 1, 2, 4, 8, 16 or 32 times their respective 90% inhibitory chloroquine concentrations for 3, 5, 7 or 14 days and then followed until recrudescence, or not, by 42 days after the end of exposure. Results Exposure to chloroquine appeared to eliminate susceptible and resistant parasites, leaving small pyknotic apparently dead parasites. Chloroquine-susceptible and -resistant parasites recrudesced after 3 and 5 days of chloroquine exposure. Recrudescence occurred in one out of four 7 day exposure series but not after 14 days exposure. The median time to recrudescence was 13 to 28 days with a range of 8 to 41 days after the end of exposure. Time to recrudescence after the end of exposure increased with duration of exposure for susceptible and resistant strains (P < 0.001). Time to recrudescence did not correlate with concentrations greater than 1× IC90. Conclusions Chloroquine-susceptible and -resistant P. falciparum probably become dormant. Elimination of dormant parasites is primarily dependent upon the duration of chloroquine exposure. Exposure to effective drug concentrations for 7 days eliminates most parasites in vitro. The results support in vivo data indicating that elimination of chloroquine-resistant P. falciparum correlates with Day 7 chloroquine concentrations.
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Affiliation(s)
- Johan Ursing
- Projecto de Saúde de Bandim, Indepth Network, Bissau, Guinea-Bissau
- Department of Clinical Sciences, Karolinska Institutet, Stockholm, Sweden
- Department of Infectious Diseases, Danderyd Hospital, Stockholm, Sweden
- Corresponding author. E-mail:
| | - Rasmus Johns
- Department of Microbiology, Tumor and Cell biology, Karolinska Institutet, Stockholm, Sweden
| | - Berit Aydin-Schmidt
- Department of Microbiology, Tumor and Cell biology, Karolinska Institutet, Stockholm, Sweden
| | - Carla Calçada
- Life and Health Sciences Research Institute (ICVS), School of Medicine, University of Minho, Braga, Portugal
- ICVS/3B’s - PT Government Associate Laboratory, Braga/Guimarães, Portugal
| | - Poul-Erik Kofoed
- Projecto de Saúde de Bandim, Indepth Network, Bissau, Guinea-Bissau
- Department of Paediatrics and Adolescent Medicine, Lillebaelt Hospital, University Hospital of Southern Denmark, Kolding, Denmark
| | - Najia Karim Ghanchi
- Department of Pathology and Laboratory Medicine, Aga Khan University, Karachi, Pakistan
| | - Maria Isabel Veiga
- Life and Health Sciences Research Institute (ICVS), School of Medicine, University of Minho, Braga, Portugal
- ICVS/3B’s - PT Government Associate Laboratory, Braga/Guimarães, Portugal
| | - Lars Rombo
- Centre for Clinical Research, Region Sörmland, Eskilstuna, Sweden
- Unit of infectious Diseases, Uppsala University, Uppsala, Sweden
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Erhunse N, Sahal D. Protecting future antimalarials from the trap of resistance: Lessons from artemisinin-based combination therapy (ACT) failures. J Pharm Anal 2021; 11:541-554. [PMID: 34765267 PMCID: PMC8572664 DOI: 10.1016/j.jpha.2020.07.005] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2020] [Revised: 07/19/2020] [Accepted: 07/19/2020] [Indexed: 11/01/2022] Open
Abstract
Having faced increased clinical treatment failures with dihydroartemisinin-piperaquine (DHA-PPQ), Cambodia swapped the first line artemisinin-based combination therapy (ACT) from DHA-PPQ to artesunate-mefloquine given that parasites resistant to piperaquine are susceptible to mefloquine. However, triple mutants have now emerged, suggesting that drug rotations may not be adequate to keep resistance at bay. There is, therefore, an urgent need for alternative treatment strategies to tackle resistance and prevent its spread. A proper understanding of all contributors to artemisinin resistance may help us identify novel strategies to keep artemisinins effective until new drugs become available for their replacement. This review highlights the role of the key players in artemisinin resistance, the current strategies to deal with it and suggests ways of protecting future antimalarial drugs from bowing to resistance as their predecessors did.
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Affiliation(s)
- Nekpen Erhunse
- Malaria Drug Discovery Research Group, International Centre for Genetic Engineering and Biotechnology, New Delhi, 110067, India
- Department of Biochemistry, Faculty of Life Sciences, University of Benin, Benin City, Edo-State, Nigeria
| | - Dinkar Sahal
- Malaria Drug Discovery Research Group, International Centre for Genetic Engineering and Biotechnology, New Delhi, 110067, India
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Maiga H, Grivoyannis A, Sagara I, Traore K, Traore OB, Tolo Y, Traore A, Bamadio A, Traore ZI, Sanogo K, Doumbo OK, Plowe CV, Djimde AA. Selection of pfcrt K76 and pfmdr1 N86 Coding Alleles after Uncomplicated Malaria Treatment by Artemether-Lumefantrine in Mali. Int J Mol Sci 2021; 22:ijms22116057. [PMID: 34205228 PMCID: PMC8200001 DOI: 10.3390/ijms22116057] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2021] [Revised: 03/18/2021] [Accepted: 03/19/2021] [Indexed: 11/18/2022] Open
Abstract
Background: Artemether-lumefantrine is a highly effective artemisinin-based combination therapy that was adopted in Mali as first-line treatment for uncomplicated Plasmodium falciparum malaria. This study was designed to measure the efficacy of artemether-lumefantrine and to assess the selection of the P. falciparum chloroquine resistance transporter (pfcrt) and P. falciparum multi-drug resistance 1 (pfmdr1) genotypes that have been associated with drug resistance. Methods: A 28-day follow-up efficacy trial of artemether-lumefantrine was conducted in patients aged 6 months and older suffering from uncomplicated falciparum malaria in four different Malian areas during the 2009 malaria transmission season. The polymorphic genetic markers MSP2, MSP1, and Ca1 were used to distinguish between recrudescence and reinfection. Reinfection and recrudescence were then grouped as recurrent infections and analyzed together by PCR-restriction fragment length polymorphism (RFLP) to identify candidate markers for artemether-lumefantrine tolerance in the P. falciparum chloroquine resistance transporter (pfcrt) gene and the P. falciparum multi-drug resistance 1 (pfmdr1) gene. Results: Clinical outcomes in 326 patients (96.7%) were analyzed and the 28-day uncorrected adequate clinical and parasitological response (ACPR) rate was 73.9%. The total PCR-corrected 28-day ACPR was 97.2%. The pfcrt 76T and pfmdr1 86Y population prevalence decreased from 49.3% and 11.0% at baseline (n = 337) to 38.8% and 0% in patients with recurrent infection (n = 85); p = 0.001), respectively. Conclusion: Parasite populations exposed to artemether-lumefantrine in this study were selected toward chloroquine-sensitivity and showed a promising trend that may warrant future targeted reintroduction of chloroquine or/and amodiaquine.
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Affiliation(s)
- Hamma Maiga
- Institut National de Sante Publique, INSP, Bamako P.O. Box 1771, Mali;
- Malaria Research & Training Center, Department of Epidemiology of Parasitic Diseases, Faculty of Pharmacy, Faculty of Medicine and Dentistry, University of Sciences, Techniques and Technologies of Bamako, Bamako P.O. Box 1805, Mali; (I.S.); (K.T.); (O.B.T.); (Y.T.); (A.T.); (A.B.); (Z.I.T.); (K.S.); (O.K.D.)
| | | | - Issaka Sagara
- Malaria Research & Training Center, Department of Epidemiology of Parasitic Diseases, Faculty of Pharmacy, Faculty of Medicine and Dentistry, University of Sciences, Techniques and Technologies of Bamako, Bamako P.O. Box 1805, Mali; (I.S.); (K.T.); (O.B.T.); (Y.T.); (A.T.); (A.B.); (Z.I.T.); (K.S.); (O.K.D.)
| | - Karim Traore
- Malaria Research & Training Center, Department of Epidemiology of Parasitic Diseases, Faculty of Pharmacy, Faculty of Medicine and Dentistry, University of Sciences, Techniques and Technologies of Bamako, Bamako P.O. Box 1805, Mali; (I.S.); (K.T.); (O.B.T.); (Y.T.); (A.T.); (A.B.); (Z.I.T.); (K.S.); (O.K.D.)
| | - Oumar B. Traore
- Malaria Research & Training Center, Department of Epidemiology of Parasitic Diseases, Faculty of Pharmacy, Faculty of Medicine and Dentistry, University of Sciences, Techniques and Technologies of Bamako, Bamako P.O. Box 1805, Mali; (I.S.); (K.T.); (O.B.T.); (Y.T.); (A.T.); (A.B.); (Z.I.T.); (K.S.); (O.K.D.)
| | - Youssouf Tolo
- Malaria Research & Training Center, Department of Epidemiology of Parasitic Diseases, Faculty of Pharmacy, Faculty of Medicine and Dentistry, University of Sciences, Techniques and Technologies of Bamako, Bamako P.O. Box 1805, Mali; (I.S.); (K.T.); (O.B.T.); (Y.T.); (A.T.); (A.B.); (Z.I.T.); (K.S.); (O.K.D.)
| | - Aliou Traore
- Malaria Research & Training Center, Department of Epidemiology of Parasitic Diseases, Faculty of Pharmacy, Faculty of Medicine and Dentistry, University of Sciences, Techniques and Technologies of Bamako, Bamako P.O. Box 1805, Mali; (I.S.); (K.T.); (O.B.T.); (Y.T.); (A.T.); (A.B.); (Z.I.T.); (K.S.); (O.K.D.)
| | - Amadou Bamadio
- Malaria Research & Training Center, Department of Epidemiology of Parasitic Diseases, Faculty of Pharmacy, Faculty of Medicine and Dentistry, University of Sciences, Techniques and Technologies of Bamako, Bamako P.O. Box 1805, Mali; (I.S.); (K.T.); (O.B.T.); (Y.T.); (A.T.); (A.B.); (Z.I.T.); (K.S.); (O.K.D.)
| | - Zoumana I. Traore
- Malaria Research & Training Center, Department of Epidemiology of Parasitic Diseases, Faculty of Pharmacy, Faculty of Medicine and Dentistry, University of Sciences, Techniques and Technologies of Bamako, Bamako P.O. Box 1805, Mali; (I.S.); (K.T.); (O.B.T.); (Y.T.); (A.T.); (A.B.); (Z.I.T.); (K.S.); (O.K.D.)
| | - Kassim Sanogo
- Malaria Research & Training Center, Department of Epidemiology of Parasitic Diseases, Faculty of Pharmacy, Faculty of Medicine and Dentistry, University of Sciences, Techniques and Technologies of Bamako, Bamako P.O. Box 1805, Mali; (I.S.); (K.T.); (O.B.T.); (Y.T.); (A.T.); (A.B.); (Z.I.T.); (K.S.); (O.K.D.)
| | - Ogobara K. Doumbo
- Malaria Research & Training Center, Department of Epidemiology of Parasitic Diseases, Faculty of Pharmacy, Faculty of Medicine and Dentistry, University of Sciences, Techniques and Technologies of Bamako, Bamako P.O. Box 1805, Mali; (I.S.); (K.T.); (O.B.T.); (Y.T.); (A.T.); (A.B.); (Z.I.T.); (K.S.); (O.K.D.)
| | | | - Abdoulaye A. Djimde
- Malaria Research & Training Center, Department of Epidemiology of Parasitic Diseases, Faculty of Pharmacy, Faculty of Medicine and Dentistry, University of Sciences, Techniques and Technologies of Bamako, Bamako P.O. Box 1805, Mali; (I.S.); (K.T.); (O.B.T.); (Y.T.); (A.T.); (A.B.); (Z.I.T.); (K.S.); (O.K.D.)
- Correspondence: ; Tel.: +223-2022-8109
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Verscheijden LFM, van der Zanden TM, van Bussel LPM, de Hoop‐Sommen M, Russel FGM, Johnson TN, de Wildt SN. Chloroquine Dosing Recommendations for Pediatric COVID-19 Supported by Modeling and Simulation. Clin Pharmacol Ther 2020; 108:248-252. [PMID: 32320477 PMCID: PMC7264731 DOI: 10.1002/cpt.1864] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2020] [Accepted: 04/21/2020] [Indexed: 12/23/2022]
Abstract
As chloroquine (CHQ) is part of the Dutch Centre for Infectious Disease Control coronavirus disease 2019 (COVID-19) experimental treatment guideline, pediatric dosing guidelines are needed. Recent pediatric data suggest that existing World Health Organization (WHO) dosing guidelines for children with malaria are suboptimal. The aim of our study was to establish best-evidence to inform pediatric CHQ doses for children infected with COVID-19. A previously developed physiologically-based pharmacokinetic (PBPK) model for CHQ was used to simulate exposure in adults and children and verified against published pharmacokinetic data. The COVID-19 recommended adult dosage regimen of 44 mg/kg total was tested in adults and children to evaluate the extent of variation in exposure. Based on differences in area under the concentration-time curve from zero to 70 hours (AUC0-70h ) the optimal CHQ dose was determined in children of different ages compared with adults. Revised doses were re-introduced into the model to verify that overall CHQ exposure in each age band was within 5% of the predicted adult value. Simulations showed differences in drug exposure in children of different ages and adults when the same body-weight based dose is given. As such, we propose the following total cumulative doses: 35 mg/kg (CHQ base) for children 0-1 month, 47 mg/kg for 1-6 months, 55 mg/kg for 6 months-12 years, and 44 mg/kg for adolescents and adults, not to exceed 3,300 mg in any patient. Our study supports age-adjusted CHQ dosing in children with COVID-19 in order to avoid suboptimal or toxic doses. The knowledge-driven, model-informed dose selection paradigm can serve as a science-based alternative to recommend pediatric dosing when pediatric clinical trial data is absent.
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Affiliation(s)
- Laurens F. M. Verscheijden
- Department of Pharmacology and ToxicologyRadboud Institute for Molecular Life SciencesRadboud University Medical CenterNijmegenThe Netherlands
| | - Tjitske M. van der Zanden
- Department of Pharmacology and ToxicologyRadboud Institute for Molecular Life SciencesRadboud University Medical CenterNijmegenThe Netherlands
- Dutch Knowledge Center Pharmacotherapy for ChildrenThe HagueThe Netherlands
- Department of PaediatricsErasmus MCSophia Children's HospitalRotterdamThe Netherlands
| | - Lianne P. M. van Bussel
- Department of Pharmacology and ToxicologyRadboud Institute for Molecular Life SciencesRadboud University Medical CenterNijmegenThe Netherlands
| | - Marika de Hoop‐Sommen
- Dutch Knowledge Center Pharmacotherapy for ChildrenThe HagueThe Netherlands
- Royal Dutch Pharmacist AssociationThe HagueThe Netherlands
| | - Frans G. M. Russel
- Department of Pharmacology and ToxicologyRadboud Institute for Molecular Life SciencesRadboud University Medical CenterNijmegenThe Netherlands
| | | | - Saskia N. de Wildt
- Department of Pharmacology and ToxicologyRadboud Institute for Molecular Life SciencesRadboud University Medical CenterNijmegenThe Netherlands
- Dutch Knowledge Center Pharmacotherapy for ChildrenThe HagueThe Netherlands
- Intensive Care and Department of Paediatrics SurgeryErasmus MC‐Sophia Children's HospitalRotterdamThe Netherlands
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9
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Karbwang J, Na‐Bangchang K. The Role of Clinical Pharmacology in Chemotherapy of Multidrug‐Resistant
Plasmodium falciparum. J Clin Pharmacol 2020; 60:830-847. [DOI: 10.1002/jcph.1589] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2019] [Accepted: 01/21/2020] [Indexed: 01/02/2023]
Affiliation(s)
- Juntra Karbwang
- Graduate Program in Bioclinical SciencesChulabhorn International College of MedicineThammasat University (Rangsit Campus) Pathumthani Thailand
- Center of Excellence in Pharmacology and Molecular Biology of Malaria and CholangiocarcinomaThammasat University (Rangsit Campus) Pathumthani Thailand
- Drug Discovery and Development Center, Office of Advanced Science and TechnologyThammasat University (Rangsit Campus) Pathumthani Thailand
- Department of Clinical Product developmentNagasaki Institute of Tropical MedicineNagasaki University Nagasaki Japan
| | - Kesara Na‐Bangchang
- Graduate Program in Bioclinical SciencesChulabhorn International College of MedicineThammasat University (Rangsit Campus) Pathumthani Thailand
- Center of Excellence in Pharmacology and Molecular Biology of Malaria and CholangiocarcinomaThammasat University (Rangsit Campus) Pathumthani Thailand
- Drug Discovery and Development Center, Office of Advanced Science and TechnologyThammasat University (Rangsit Campus) Pathumthani Thailand
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10
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High-Dose Chloroquine for Uncomplicated Plasmodium falciparum Malaria Is Well Tolerated and Causes Similar QT Interval Prolongation as Standard-Dose Chloroquine in Children. Antimicrob Agents Chemother 2020; 64:AAC.01846-19. [PMID: 31907183 DOI: 10.1128/aac.01846-19] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2019] [Accepted: 12/20/2019] [Indexed: 01/08/2023] Open
Abstract
Higher chloroquine doses can effectively treat up to 93 to 96% of malaria infections caused by Plasmodium falciparum carrying the resistance-conferring chloroquine resistance transporter (pfcrt) 76T allele. The tolerability of 50 (double the standard dose) and 70 mg/kg total chloroquine doses were assessed in this study. Fifteen 4- to 8-year-old children with uncomplicated malaria were given 10 mg/kg of chloroquine twice daily for 2 days and 5 mg/kg twice daily on the third day. Fifteen additional children were given 5 mg/kg twice daily for 2 more days. Chloroquine concentrations, blood pressure, electrocardiograms (ECGs), parasite density, and adverse events were assessed until day 28. Both dosages were well tolerated, and symptoms resolved by day 3 in parallel with increasing chloroquine concentrations. The median corrected QT (QTc) interval was 12 to 26 ms higher at expected peak concentrations than at day 0 (P < 0.001). Pfcrt 76T was associated with delayed parasite clearance. Day 28 clinical and parasitological responses against P. falciparum with pfcrt 76T were 57% (4/7) and 67% (4/6) after treatment with 50 and 70 mg/kg, respectively. Dosages were well tolerated, and no severe cardiac adverse events occurred. The QTc interval increase was similar to that found in adults taking 25 mg/kg of chloroquine. (This study has been registered at ClinicalTrials.gov under identifier NCT01814423.).
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11
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Resistance to Artemisinin Combination Therapies (ACTs): Do Not Forget the Partner Drug! Trop Med Infect Dis 2019; 4:tropicalmed4010026. [PMID: 30717149 PMCID: PMC6473515 DOI: 10.3390/tropicalmed4010026] [Citation(s) in RCA: 60] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/27/2018] [Revised: 01/30/2019] [Accepted: 01/30/2019] [Indexed: 01/30/2023] Open
Abstract
Artemisinin-based combination therapies (ACTs) have become the mainstay for malaria treatment in almost all malaria endemic settings. Artemisinin derivatives are highly potent and fast acting antimalarials; but they have a short half-life and need to be combined with partner drugs with a longer half-life to clear the remaining parasites after a standard 3-day ACT regimen. When introduced, ACTs were highly efficacious and contributed to the steep decrease of malaria over the last decades. However, parasites with decreased susceptibility to artemisinins have emerged in the Greater Mekong Subregion (GMS), followed by ACTs’ failure, due to both decreased susceptibility to artemisinin and partner drug resistance. Therefore, there is an urgent need to strengthen and expand current resistance surveillance systems beyond the GMS to track the emergence or spread of artemisinin resistance. Great attention has been paid to the spread of artemisinin resistance over the last five years, since molecular markers of decreased susceptibility to artemisinin in the GMS have been discovered. However, resistance to partner drugs is critical, as ACTs can still be effective against parasites with decreased susceptibility to artemisinins, when the latter are combined with a highly efficacious partner drug. This review outlines the different mechanisms of resistance and molecular markers associated with resistance to partner drugs for the currently used ACTs. Strategies to improve surveillance and potential solutions to extend the useful therapeutic lifespan of the currently available malaria medicines are proposed.
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12
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Kloprogge F, Workman L, Borrmann S, Tékété M, Lefèvre G, Hamed K, Piola P, Ursing J, Kofoed PE, Mårtensson A, Ngasala B, Björkman A, Ashton M, Friberg Hietala S, Aweeka F, Parikh S, Mwai L, Davis TME, Karunajeewa H, Salman S, Checchi F, Fogg C, Newton PN, Mayxay M, Deloron P, Faucher JF, Nosten F, Ashley EA, McGready R, van Vugt M, Proux S, Price RN, Karbwang J, Ezzet F, Bakshi R, Stepniewska K, White NJ, Guerin PJ, Barnes KI, Tarning J. Artemether-lumefantrine dosing for malaria treatment in young children and pregnant women: A pharmacokinetic-pharmacodynamic meta-analysis. PLoS Med 2018; 15:e1002579. [PMID: 29894518 PMCID: PMC5997317 DOI: 10.1371/journal.pmed.1002579] [Citation(s) in RCA: 41] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/22/2017] [Accepted: 05/04/2018] [Indexed: 01/13/2023] Open
Abstract
BACKGROUND The fixed dose combination of artemether-lumefantrine (AL) is the most widely used treatment for uncomplicated Plasmodium falciparum malaria. Relatively lower cure rates and lumefantrine levels have been reported in young children and in pregnant women during their second and third trimester. The aim of this study was to investigate the pharmacokinetic and pharmacodynamic properties of lumefantrine and the pharmacokinetic properties of its metabolite, desbutyl-lumefantrine, in order to inform optimal dosing regimens in all patient populations. METHODS AND FINDINGS A search in PubMed, Embase, ClinicalTrials.gov, Google Scholar, conference proceedings, and the WorldWide Antimalarial Resistance Network (WWARN) pharmacology database identified 31 relevant clinical studies published between 1 January 1990 and 31 December 2012, with 4,546 patients in whom lumefantrine concentrations were measured. Under the auspices of WWARN, relevant individual concentration-time data, clinical covariates, and outcome data from 4,122 patients were made available and pooled for the meta-analysis. The developed lumefantrine population pharmacokinetic model was used for dose optimisation through in silico simulations. Venous plasma lumefantrine concentrations 7 days after starting standard AL treatment were 24.2% and 13.4% lower in children weighing <15 kg and 15-25 kg, respectively, and 20.2% lower in pregnant women compared with non-pregnant adults. Lumefantrine exposure decreased with increasing pre-treatment parasitaemia, and the dose limitation on absorption of lumefantrine was substantial. Simulations using the lumefantrine pharmacokinetic model suggest that, in young children and pregnant women beyond the first trimester, lengthening the dose regimen (twice daily for 5 days) and, to a lesser extent, intensifying the frequency of dosing (3 times daily for 3 days) would be more efficacious than using higher individual doses in the current standard treatment regimen (twice daily for 3 days). The model was developed using venous plasma data from patients receiving intact tablets with fat, and evaluations of alternative dosing regimens were consequently only representative for venous plasma after administration of intact tablets with fat. The absence of artemether-dihydroartemisinin data limited the prediction of parasite killing rates and recrudescent infections. Thus, the suggested optimised dosing schedule was based on the pharmacokinetic endpoint of lumefantrine plasma exposure at day 7. CONCLUSIONS Our findings suggest that revised AL dosing regimens for young children and pregnant women would improve drug exposure but would require longer or more complex schedules. These dosing regimens should be evaluated in prospective clinical studies to determine whether they would improve cure rates, demonstrate adequate safety, and thereby prolong the useful therapeutic life of this valuable antimalarial treatment.
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Affiliation(s)
- Frank Kloprogge
- WorldWide Antimalarial Resistance Network, Bangkok, Thailand
- Centre for Tropical Medicine and Global Health, University of Oxford, Oxford, United Kingdom
- Institute for Global Health, University College London, London, United Kingdom
| | - Lesley Workman
- WorldWide Antimalarial Resistance Network, Cape Town, South Africa
- Division of Clinical Pharmacology, Department of Medicine, University of Cape Town, Cape Town, South Africa
| | - Steffen Borrmann
- Kenya Medical Research Institute–Wellcome Trust Research Programme, Kilifi, Kenya
- Institute for Tropical Medicine, Eberhard Karls University of Tübingen, Tübingen, Germany
| | - Mamadou Tékété
- Institute for Tropical Medicine, Eberhard Karls University of Tübingen, Tübingen, Germany
- Malaria Research and Training Center, Department of Epidemiology of Parasitic Diseases, Faculty of Pharmacy, University of Science, Techniques and Technologies of Bamako, Bamako, Mali
| | | | - Kamal Hamed
- Novartis Pharmaceuticals, East Hanover, New Jersey, United States of America
| | | | - Johan Ursing
- Department of Microbiology, Tumor and Cell Biology, Karolinska Institutet, Stockholm, Sweden
- Department of Infectious Diseases, Danderyds Hospital, Stockholm, Sweden
- Bandim Health Project, Bissau, Guinea-Bissau
| | - Poul Erik Kofoed
- Bandim Health Project, Bissau, Guinea-Bissau
- Department of Paediatrics, Kolding Hospital, Kolding, Denmark
| | - Andreas Mårtensson
- Department of Women’s and Children’s Health, International Maternal and Child Health, Uppsala University, Uppsala, Sweden
| | - Billy Ngasala
- Muhimbili University of Health and Allied Sciences, Dar es Salaam, Tanzania
| | | | - Michael Ashton
- Department of Pharmacology, University of Gothenburg, Gothenburg, Sweden
| | - Sofia Friberg Hietala
- Department of Pharmacology, University of Gothenburg, Gothenburg, Sweden
- Pharmetheus, Uppsala, Sweden
| | - Francesca Aweeka
- UCSF School of Pharmacy, San Francisco, California, United States of America
| | - Sunil Parikh
- Yale School of Public Health, New Haven, Connecticut, United States of America
| | - Leah Mwai
- Kenya Medical Research Institute–Wellcome Trust Research Programme, Kilifi, Kenya
- Institute for Tropical Medicine and Joanna Briggs Institute Affiliate Centre for Evidence Based Health Care Evidence Synthesis and Translation Unit, Afya Research Africa, Nairobi, Kenya
- International Development Research Centre, Ottawa, Ontario, Canada
| | - Timothy M. E. Davis
- Medical School, Faculty of Health and Medical Sciences, The University of Western Australia, Perth, Western Australia, Australia
| | - Harin Karunajeewa
- Walter and Eliza Hall Institute of Medical Research, Melbourne, Victoria, Australia
| | - Sam Salman
- Medical School, Faculty of Health and Medical Sciences, The University of Western Australia, Perth, Western Australia, Australia
| | - Francesco Checchi
- Epicentre, Paris, France
- Department of Infectious Disease Epidemiology, London School of Hygiene & Tropical Medicine, London, United Kingdom
| | - Carole Fogg
- Epicentre, Paris, France
- Faculty of Science, University of Portsmouth, Portsmouth, United Kingdom
| | - Paul N. Newton
- Centre for Tropical Medicine and Global Health, University of Oxford, Oxford, United Kingdom
- Lao–Oxford–Mahosot Hospital–Wellcome Trust Research Unit, Vientiane, Laos
| | - Mayfong Mayxay
- Centre for Tropical Medicine and Global Health, University of Oxford, Oxford, United Kingdom
- Lao–Oxford–Mahosot Hospital–Wellcome Trust Research Unit, Vientiane, Laos
- Faculty of Postgraduate Studies, University of Health Sciences, Vientiane, Laos
| | - Philippe Deloron
- UMR216 Institut de Recherche pour le Développement, Faculté de Pharmacie, Université Paris Descartes, Paris, France
| | | | - François Nosten
- Centre for Tropical Medicine and Global Health, University of Oxford, Oxford, United Kingdom
- Shoklo Malaria Research Unit, Mae Sot, Thailand
| | - Elizabeth A. Ashley
- Centre for Tropical Medicine and Global Health, University of Oxford, Oxford, United Kingdom
- Myanmar Oxford Clinical Research Unit, Yangon, Myanmar
| | - Rose McGready
- Centre for Tropical Medicine and Global Health, University of Oxford, Oxford, United Kingdom
- Shoklo Malaria Research Unit, Mae Sot, Thailand
| | - Michele van Vugt
- Shoklo Malaria Research Unit, Mae Sot, Thailand
- Amsterdam Medical Centre, Amsterdam, The Netherlands
| | - Stephane Proux
- Centre for Tropical Medicine and Global Health, University of Oxford, Oxford, United Kingdom
- Shoklo Malaria Research Unit, Mae Sot, Thailand
| | - Ric N. Price
- Centre for Tropical Medicine and Global Health, University of Oxford, Oxford, United Kingdom
- WorldWide Antimalarial Resistance Network, Darwin, Northern Territory, Australia
- Global and Tropical Health Division, Menzies School of Health Research, Darwin, Northern Territory, Australia
- Charles Darwin University, Darwin, Northern Territory, Australia
| | - Juntra Karbwang
- Institute of Tropical Medicine, Nagasaki University, Nagasaki, Japan
| | - Farkad Ezzet
- Novartis Pharmaceuticals, East Hanover, New Jersey, United States of America
| | | | - Kasia Stepniewska
- Centre for Tropical Medicine and Global Health, University of Oxford, Oxford, United Kingdom
- WorldWide Antimalarial Resistance Network, Oxford, United Kingdom
| | - Nicholas J. White
- Centre for Tropical Medicine and Global Health, University of Oxford, Oxford, United Kingdom
- Mahidol–Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand
| | - Philippe J. Guerin
- Centre for Tropical Medicine and Global Health, University of Oxford, Oxford, United Kingdom
- WorldWide Antimalarial Resistance Network, Oxford, United Kingdom
| | - Karen I. Barnes
- WorldWide Antimalarial Resistance Network, Cape Town, South Africa
- Division of Clinical Pharmacology, Department of Medicine, University of Cape Town, Cape Town, South Africa
| | - Joel Tarning
- WorldWide Antimalarial Resistance Network, Bangkok, Thailand
- Centre for Tropical Medicine and Global Health, University of Oxford, Oxford, United Kingdom
- Mahidol–Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand
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13
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Ursing J, Rombo L, Rodrigues A, Kofoed PE. Artemether-Lumefantrine versus Dihydroartemisinin-Piperaquine for Treatment of Uncomplicated Plasmodium falciparum Malaria in Children Aged Less than 15 Years in Guinea-Bissau - An Open-Label Non-Inferiority Randomised Clinical Trial. PLoS One 2016; 11:e0161495. [PMID: 27649561 PMCID: PMC5030079 DOI: 10.1371/journal.pone.0161495] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2016] [Accepted: 08/01/2016] [Indexed: 12/28/2022] Open
Abstract
Background Artemether-lumefantrine (AL) was introduced for treatment of uncomplicated malaria in Guinea-Bissau in 2008. Malaria then resurged and recurrent malaria after treatment with AL and stock-outs of AL were common. This study therefore aimed to assess the efficacy of AL and identify an alternative second line antimalarial. Dihydroartemisinin-piperaquine (DP) was chosen as it has been shown to be safe and efficacious and to reduce the incidence of recurrent malaria. Methods and Findings In a multicentre randomised open-label non-inferiority clinical trial, AL or DP were given over 3 days to children aged 6 months-15 years with uncomplicated P. falciparum mono-infection. Intake was observed and AL was given with milk. Children were seen on days 0, 1, 2 and 3 and then weekly days 7–42. Recurring P. falciparum were classified as recrudescence or new infections by genotyping. Between November 2012 and July 2015, 312 children were randomised to AL (n = 155) or DP (n = 157). The day 42 PCR adjusted per protocol adequate clinical and parasitological responses were 95% and 100% in the AL and DP groups respectively, Mantel-Haenszel weighted odds ratio (OR) 0.22 (95% CI 0–0.68), p = 0.022. In a modified intention to treat analysis in which treatment failures day 0 and reinfections were also considered as treatment failures adequate clinical and parasitological responses were 94% and 97% (OR 0.42 [95% CI, 0.13–1.38], p = 0.15). Parasite clearance and symptom resolution were similar with both treatments. Conclusions Both treatments achieved the WHO recommended efficacy for antimalarials about to be adopted as policy. DP was not inferior to AL for treatment of uncomplicated P. falciparum malaria in Guinea-Bissau. Trial Registration ClinicalTrials.gov NTC01704508
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Affiliation(s)
- Johan Ursing
- Projecto de Saúde de Bandim, Indepth Network, Bissau, Guinea-Bissau
- Department of Microbiology, Tumor and Cell Biology, Karolinska Institutet Nobels väg 16, 171 65, Stockholm, Sweden
- Department of Infectious Diseases, Danderyds Hospital, Stockholm, Sweden
- * E-mail: (JU); (PEK)
| | - Lars Rombo
- Department of Microbiology, Tumor and Cell Biology, Karolinska Institutet Nobels väg 16, 171 65, Stockholm, Sweden
- Centre for Clinical Research, Sörmland county council, Eskilstuna, Sweden and Uppsala University, Uppsala, Sweden
| | | | - Poul-Erik Kofoed
- Projecto de Saúde de Bandim, Indepth Network, Bissau, Guinea-Bissau
- Department of Paediatrics, Kolding Hospital, Kolding, Denmark
- * E-mail: (JU); (PEK)
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14
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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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15
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Tchaparian E, Sambol NC, Arinaitwe E, McCormack SA, Bigira V, Wanzira H, Muhindo M, Creek DJ, Sukumar N, Blessborn D, Tappero JW, Kakuru A, Bergqvist Y, Aweeka FT, Parikh S. Population Pharmacokinetics and Pharmacodynamics of Lumefantrine in Young Ugandan Children Treated With Artemether-Lumefantrine for Uncomplicated Malaria. J Infect Dis 2016; 214:1243-51. [PMID: 27471317 PMCID: PMC5034953 DOI: 10.1093/infdis/jiw338] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2016] [Accepted: 07/23/2016] [Indexed: 12/21/2022] Open
Abstract
Background. The pharmacokinetics and pharmacodynamics of lumefantrine, a component of the most widely used treatment for malaria, artemether-lumefantrine, has not been adequately characterized in young children. Methods. Capillary whole-blood lumefantrine concentration and treatment outcomes were determined in 105 Ugandan children, ages 6 months to 2 years, who were treated for 249 episodes of Plasmodium falciparum malaria with artemether-lumefantrine. Results. Population pharmacokinetics for lumefantrine used a 2-compartment open model with first-order absorption. Age had a significant positive correlation with bioavailability in a model that included allometric scaling. Children not receiving trimethoprim-sulfamethoxazole with capillary whole blood concentrations <200 ng/mL had a 3-fold higher hazard of 28-day recurrent parasitemia, compared with those with concentrations >200 ng/mL (P = .0007). However, for children receiving trimethoprim-sulfamethoxazole, the risk of recurrent parasitemia did not differ significantly on the basis of this threshold. Day 3 concentrations were a stronger predictor of 28-day recurrence than day 7 concentrations. Conclusions. We demonstrate that age, in addition to weight, is a determinant of lumefantrine exposure, and in the absence of trimethoprim-sulfamethoxazole, lumefantrine exposure is a determinant of recurrent parasitemia. Exposure levels in children aged 6 months to 2 years was generally lower than levels published for older children and adults. Further refinement of artemether-lumefantrine dosing to improve exposure in infants and very young children may be warranted.
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Affiliation(s)
- Eskouhie Tchaparian
- Department of Bioengineering and Therapeutic Sciences, University of California San Francisco
| | - Nancy C Sambol
- Department of Bioengineering and Therapeutic Sciences, University of California San Francisco
| | | | - Shelley A McCormack
- Department of Bioengineering and Therapeutic Sciences, University of California San Francisco
| | - Victor Bigira
- Infectious Diseases Research Collaboration, Kampala, Uganda
| | | | - Mary Muhindo
- Infectious Diseases Research Collaboration, Kampala, Uganda
| | - Darren J Creek
- Monash Institute of Pharmaceutical Sciences, Monash University, Parkville, Australia
| | - Nitin Sukumar
- Yale School of Public Health, New Haven, Connecticut
| | | | - Jordan W Tappero
- Centers for Global Health, Centers for Disease Control and Prevention, Atlanta, Georgia
| | - Abel Kakuru
- Infectious Diseases Research Collaboration, Kampala, Uganda
| | | | | | - Sunil Parikh
- Yale School of Public Health, New Haven, Connecticut
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16
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Abstract
Maciej F. Boni and colleagues propose deploying multiple first-line combination therapies against malaria within a community to delay drug-resistance evolution.
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17
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Ursing J, Rombo L, Bergqvist Y, Rodrigues A, Kofoed PE. High-Dose Chloroquine for Treatment of Chloroquine-Resistant Plasmodium falciparum Malaria. J Infect Dis 2015; 213:1315-21. [PMID: 26656124 DOI: 10.1093/infdis/jiv590] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2015] [Accepted: 11/30/2015] [Indexed: 11/13/2022] Open
Abstract
BACKGROUND Due to development of multidrug-resistant Plasmodium falciparum new antimalarial therapies are needed. In Guinea-Bissau, routinely used triple standard-dose chloroquine remained effective for decades despite the existence of "chloroquine-resistant" P. falciparum. This study aimed to determine the in vivo efficacy of higher chloroquine concentrations against P. falciparum with resistance-conferring genotypes. METHODS Standard or double-dose chloroquine was given to 892 children aged <15 years with uncomplicated malaria during 3 clinical trials (2001-2008) with ≥ 35 days follow-up. The P. falciparum resistance-conferring genotype (pfcrt 76T) and day 7 chloroquine concentrations were determined. Data were divided into age groups (<5, 5-9, and 10-14 years) because concentrations increase with age when chloroquine is prescribed according to body weight. RESULTS Adequate clinical and parasitological responses were 14%, 38%, and 39% after standard-dose and 66%, 84%, and 91% after double-dose chloroquine in children aged <5, 5-9, and 10-14 years, respectively, and infected with P. falciparum genotypes conferring chloroquine resistance (n = 195, P < .001). In parallel, median chloroquine concentrations were 471, 688, and 809 nmol/L for standard-dose and 1040, 1494, and 1585 nmol/L for double-dose chloroquine. CONCLUSIONS Chloroquine resistance is dose dependent and can be overcome by higher, still well-tolerated doses.
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Affiliation(s)
- Johan Ursing
- Projecto de Saúde de Bandim, Indepth Network, Bissau, Guinea-Bissau Department of Microbiology, Tumor and Cell Biology, Karolinska Institutet Department of Infectious Diseases, Danderyds Hospital, Stockholm
| | - Lars Rombo
- Department of Microbiology, Tumor and Cell Biology, Karolinska Institutet Centre for Clinical Research, Sörmland County Council, Eskilstuna, and Uppsala University
| | | | | | - Poul-Erik Kofoed
- Projecto de Saúde de Bandim, Indepth Network, Bissau, Guinea-Bissau Department of Paediatrics, Kolding Hospital, Denmark
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18
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Artemether-lumefantrine treatment of uncomplicated Plasmodium falciparum malaria: a systematic review and meta-analysis of day 7 lumefantrine concentrations and therapeutic response using individual patient data. BMC Med 2015; 13:227. [PMID: 26381375 PMCID: PMC4574542 DOI: 10.1186/s12916-015-0456-7] [Citation(s) in RCA: 73] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/14/2015] [Accepted: 08/18/2015] [Indexed: 01/24/2023] Open
Abstract
BACKGROUND Achieving adequate antimalarial drug exposure is essential for curing malaria. Day 7 blood or plasma lumefantrine concentrations provide a simple measure of drug exposure that correlates well with artemether-lumefantrine efficacy. However, the 'therapeutic' day 7 lumefantrine concentration threshold needs to be defined better, particularly for important patient and parasite sub-populations. METHODS The WorldWide Antimalarial Resistance Network (WWARN) conducted a large pooled analysis of individual pharmacokinetic-pharmacodynamic data from patients treated with artemether-lumefantrine for uncomplicated Plasmodium falciparum malaria, to define therapeutic day 7 lumefantrine concentrations and identify patient factors that substantially alter these concentrations. A systematic review of PubMed, Embase, Google Scholar, ClinicalTrials.gov and conference proceedings identified all relevant studies. Risk of bias in individual studies was evaluated based on study design, methodology and missing data. RESULTS Of 31 studies identified through a systematic review, 26 studies were shared with WWARN and 21 studies with 2,787 patients were included. Recrudescence was associated with low day 7 lumefantrine concentrations (HR 1.59 (95% CI 1.36 to 1.85) per halving of day 7 concentrations) and high baseline parasitemia (HR 1.87 (95% CI 1.22 to 2.87) per 10-fold increase). Adjusted for mg/kg dose, day 7 concentrations were lowest in very young children (<3 years), among whom underweight-for-age children had 23% (95% CI -1 to 41%) lower concentrations than adequately nourished children of the same age and 53% (95% CI 37 to 65%) lower concentrations than adults. Day 7 lumefantrine concentrations were 44% (95% CI 38 to 49%) lower following unsupervised treatment. The highest risk of recrudescence was observed in areas of emerging artemisinin resistance and very low transmission intensity. For all other populations studied, day 7 concentrations ≥200 ng/ml were associated with >98% cure rates (if parasitemia <135,000/μL). CONCLUSIONS Current artemether-lumefantrine dosing recommendations achieve day 7 lumefantrine concentrations ≥200 ng/ml and high cure rates in most uncomplicated malaria patients. Three groups are at increased risk of treatment failure: very young children (particularly those underweight-for-age); patients with high parasitemias; and patients in very low transmission intensity areas with emerging parasite resistance. In these groups, adherence and treatment response should be monitored closely. Higher, more frequent, or prolonged dosage regimens should now be evaluated in very young children, particularly if malnourished, and in patients with hyperparasitemia.
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Djimde AA, Makanga M, Kuhen K, Hamed K. The emerging threat of artemisinin resistance in malaria: focus on artemether-lumefantrine. Expert Rev Anti Infect Ther 2015; 13:1031-45. [PMID: 26081265 DOI: 10.1586/14787210.2015.1052793] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
The development of artemisinin resistance in the Greater Mekong Subregion poses a significant threat to malaria elimination. Artemisinin-based combination therapies including artemether-lumefantrine (AL) are recommended by WHO as first-line treatment for uncomplicated Plasmodium falciparum malaria. This article provides a comprehensive review of the existing and latest data as a basis for interpretation of observed variability in parasite sensitivity to AL over the last 5 years. Clinical efficacy and preclinical data from a range of endemic countries are summarized, including potential molecular markers of resistance. Overall, AL remains effective in the treatment of uncomplicated P. falciparum malaria in most regions. Establishing validated molecular markers for resistance and strict efficacy monitoring will reinforce timely updates of treatment policies.
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Affiliation(s)
- Abdoulaye A Djimde
- Malaria Research and Training Center, University of Science, Techniques and Technologies of Bamako, Bamako, Mali
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20
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Temporal and seasonal changes of genetic polymorphisms associated with altered drug susceptibility to chloroquine, lumefantrine, and quinine in Guinea-Bissau between 2003 and 2012. Antimicrob Agents Chemother 2014; 59:872-9. [PMID: 25421474 DOI: 10.1128/aac.03554-14] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023] Open
Abstract
In 2008, artemether-lumefantrine was introduced in Guinea-Bissau, West Africa, but quinine has also been commonly prescribed for the treatment of uncomplicated Plasmodium falciparum malaria. An efficacious high-dose chloroquine treatment regimen was used previously. Temporal and seasonal changes of genetic polymorphisms associated with altered drug susceptibility to chloroquine, lumefantrine, and quinine have been described. P. falciparum chloroquine resistance transporter (pfcrt) K76T, pfmdr1 gene copy numbers, pfmdr1 polymorphisms N86Y and Y184F, and pfmdr1 sequences 1034 to 1246 were determined using PCR-based methods. Blood samples came from virtually all (n=1,806) children<15 years of age who had uncomplicated P. falciparum monoinfection and presented at a health center in suburban Bissau (from 2003 to 2012). The pfcrt K76T and pfmdr1 N86Y frequencies were stable, and seasonal changes were not seen from 2003 to 2007. Since 2007, the mean annual frequencies increased (P<0.001) for pfcrt 76T (24% to 57%), pfmdr1 N86 (72% to 83%), and pfcrt 76+pfmdr1 86 TN (10% to 27%), and pfcrt 76T accumulated during the high transmission season (P=0.001). The pfmdr1 86+184 NF frequency increased from 39% to 66% (from 2003 to 2011; P=0.004). One sample had two pfmdr1 gene copies. pfcrt 76T was associated with a lower parasite density (P<0.001). Following the discontinuation of an effective chloroquine regimen, probably highly artemether-lumefantrine-susceptible P. falciparum (with pfcrt 76T) accumulated, possibly due to suboptimal use of quinine and despite a fitness cost linked to pfcrt 76T. (The studies reported here were registered at ClinicalTrials.gov under registration no. NCT00137514 [PSB-2001-chl-amo], NCT00137566 [PSB-2004-paracetamol], NCT00426439 [PSB-2006-coartem], NCT01157689 [AL-eff 2010], and NCT01704508 [Eurartesim 2012].).
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21
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Bellanca S, Summers RL, Meyrath M, Dave A, Nash MN, Dittmer M, Sanchez CP, Stein WD, Martin RE, Lanzer M. Multiple drugs compete for transport via the Plasmodium falciparum chloroquine resistance transporter at distinct but interdependent sites. J Biol Chem 2014; 289:36336-51. [PMID: 25378409 PMCID: PMC4276893 DOI: 10.1074/jbc.m114.614206] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Mutations in the "chloroquine resistance transporter" (PfCRT) are a major determinant of drug resistance in the malaria parasite Plasmodium falciparum. We have previously shown that mutant PfCRT transports the antimalarial drug chloroquine away from its target, whereas the wild-type form of PfCRT does not. However, little is understood about the transport of other drugs via PfCRT or the mechanism by which PfCRT recognizes different substrates. Here we show that mutant PfCRT also transports quinine, quinidine, and verapamil, indicating that the protein behaves as a multidrug resistance carrier. Detailed kinetic analyses revealed that chloroquine and quinine compete for transport via PfCRT in a manner that is consistent with mixed-type inhibition. Moreover, our analyses suggest that PfCRT accepts chloroquine and quinine at distinct but antagonistically interacting sites. We also found verapamil to be a partial mixed-type inhibitor of chloroquine transport via PfCRT, further supporting the idea that PfCRT possesses multiple substrate-binding sites. Our findings provide new mechanistic insights into the workings of PfCRT, which could be exploited to design potent inhibitors of this key mediator of drug resistance.
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Affiliation(s)
- Sebastiano Bellanca
- From the Department of Infectious Diseases, Parasitology, Heidelberg University, Im Neuenheimer Feld 324, 69120 Heidelberg, Germany
| | - Robert L Summers
- the Research School of Biology, Australian National University, Canberra, Australian Capital Territory 0200, Australia, and
| | - Max Meyrath
- From the Department of Infectious Diseases, Parasitology, Heidelberg University, Im Neuenheimer Feld 324, 69120 Heidelberg, Germany
| | - Anurag Dave
- From the Department of Infectious Diseases, Parasitology, Heidelberg University, Im Neuenheimer Feld 324, 69120 Heidelberg, Germany
| | - Megan N Nash
- the Research School of Biology, Australian National University, Canberra, Australian Capital Territory 0200, Australia, and
| | - Martin Dittmer
- From the Department of Infectious Diseases, Parasitology, Heidelberg University, Im Neuenheimer Feld 324, 69120 Heidelberg, Germany
| | - Cecilia P Sanchez
- From the Department of Infectious Diseases, Parasitology, Heidelberg University, Im Neuenheimer Feld 324, 69120 Heidelberg, Germany
| | - Wilfred D Stein
- the Department of Biological Chemistry, Silberman Institute of Life Sciences, Hebrew University of Jerusalem, Jerusalem 91904, Israel
| | - Rowena E Martin
- the Research School of Biology, Australian National University, Canberra, Australian Capital Territory 0200, Australia, and
| | - Michael Lanzer
- From the Department of Infectious Diseases, Parasitology, Heidelberg University, Im Neuenheimer Feld 324, 69120 Heidelberg, Germany,
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Kay K, Hodel EM, Hastings IM. Improving the role and contribution of pharmacokinetic analyses in antimalarial drug clinical trials. Antimicrob Agents Chemother 2014; 58:5643-9. [PMID: 24982091 PMCID: PMC4187976 DOI: 10.1128/aac.02777-14] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023] Open
Abstract
It is now World Health Organization (WHO) policy that drug concentrations on day 7 be measured as part of routine assessment in antimalarial drug efficacy trials. The rationale is that this single pharmacological measure serves as a simple and practical predictor of treatment outcome for antimalarial drugs with long half-lives. Herein we review theoretical data and field studies and conclude that the day 7 drug concentration (d7c) actually appears to be a poor predictor of therapeutic outcome. This poor predictive capability combined with the fact that many routine antimalarial trials will have few or no failures means that there appears to be little justification for this WHO recommendation. Pharmacological studies have a huge potential to improve antimalarial dosing, and we propose study designs that use more-focused, sophisticated, and cost-effective ways of generating these data than the mass collection of single d7c concentrations.
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Affiliation(s)
- Katherine Kay
- Liverpool School of Tropical Medicine, Liverpool, United Kingdom
| | - Eva Maria Hodel
- Liverpool School of Tropical Medicine, Liverpool, United Kingdom
| | - Ian M Hastings
- Liverpool School of Tropical Medicine, Liverpool, United Kingdom
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23
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Interspecies allometric scaling of antimalarial drugs and potential application to pediatric dosing. Antimicrob Agents Chemother 2014; 58:6068-78. [PMID: 25092696 DOI: 10.1128/aac.02538-14] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Pharmacopeial recommendations for administration of antimalarial drugs are the same weight-based (mg/kg of body weight) doses for children and adults. However, linear calculations are known to underestimate pediatric doses; therefore, interspecies allometric scaling data may have a role in predicting doses in children. We investigated the allometric scaling relationships of antimalarial drugs using data from pharmacokinetic studies in mammalian species. Simple allometry (Y = a × W(b)) was utilized and compared to maximum life span potential (MLP) correction. All drugs showed a strong correlation with clearance (CL) in healthy controls. Insufficient data from malaria-infected species other than humans were available for allometric scaling. The allometric exponents (b) for CL of artesunate, dihydroartemisinin (from intravenous artesunate), artemether, artemisinin, clindamycin, piperaquine, mefloquine, and quinine were 0.71, 0.85, 0.66, 0.83, 0.62, 0.96, 0.52, and 0.40, respectively. Clearance was significantly lower in malaria infection than in healthy (adult) humans for quinine (0.07 versus 0.17 liter/h/kg; P = 0.0002) and dihydroartemisinin (0.81 versus 1.11 liters/h/kg; P = 0.04; power = 0.6). Interpolation of simple allometry provided better estimates of CL for children than MLP correction, which generally underestimated CL values. Pediatric dose calculations based on simple allometric exponents were 10 to 70% higher than pharmacopeial (mg/kg) recommendations. Interpolation of interspecies allometric scaling could provide better estimates than linear scaling of adult to pediatric doses of antimalarial drugs; however, the use of a fixed exponent for CL was not supported in the present study. The variability in allometric exponents for antimalarial drugs also has implications for scaling of fixed-dose combinations.
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Ursing J, Rombo L, Rodrigues A, Aaby P, Kofoed PE. Malaria transmission in Bissau, Guinea-Bissau between 1995 and 2012: malaria resurgence did not negatively affect mortality. PLoS One 2014; 9:e101167. [PMID: 24984039 PMCID: PMC4077730 DOI: 10.1371/journal.pone.0101167] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2014] [Accepted: 06/03/2014] [Indexed: 11/19/2022] Open
Abstract
Introduction As Plasmodium falciparum prevalence decreases in many parts of Sub-Saharan Africa, so does immunity resulting in larger at risk populations and increased risk of malaria resurgence. In Bissau, malaria prevalence decreased from ∼50% to 3% between 1995 and 2003. The epidemiological characteristics of P. falciparum malaria within Bandim health and demographic surveillance site (population ∼100000) between 1995 and 2012 are described. Methods and Findings The population was determined by census. 3603 children aged <15 years that were enrolled in clinical trials at the Bandim health centre (1995–2012) were considered incident cases. The mean annual malaria incidence per thousand children in 1995–1997, 1999–2003, 2007, 2011, 2012 were as follows; age <5 years 22→29→4→9→3, age 5–9 years 15→28→4→33→12, age 10–14 years 9→15→1→45→19. There were 4 campaigns (2003–2010) to increase use of insecticide treated bed nets (ITN) amongst children <5 years. An efficacious high-dose chloroquine treatment regime was routinely used until artemisinin based combination therapy (ACT) was introduced in 2008. Long lasting insecticide treated bed nets (LLIN) were distributed in 2011. By 2012 there was 1 net per 2 people and 97% usage. All-cause mortality decreased from post-war peaks in 1999 until 2012 in all age groups and was not negatively affected by malaria resurgence. Conclusion The cause of decreasing malaria incidence (1995–2007) was probably multifactorial and coincident with the use of an efficacious high-dose chloroquine treatment regime. Decreasing malaria prevalence created a susceptible group of older children in which malaria resurged, highlighting the need to include all age groups in malaria interventions. ACT did not hinder malaria resurgence. Mass distribution of LLINs probably curtailed malaria epidemics. All-cause mortality was not negatively affected by malaria resurgence.
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Affiliation(s)
- Johan Ursing
- Projecto de Saúde de Bandim, Indepth Network, Bissau, Guinea-Bissau
- Malaria Research Laboratory, Unit of Infectious Diseases, Department of Medicine, Karolinska University Hospital, Stockholm, Sweden
- Department of microbiology, Tumor and Cell Biology, Karolinska Institutet, Solna, Sweden
- * E-mail: (JU); (P-EK)
| | - Lars Rombo
- Malaria Research Laboratory, Unit of Infectious Diseases, Department of Medicine, Karolinska University Hospital, Stockholm, Sweden
- Department of Infectious Diseases Mälarsjukhuset, Eskilstuna, Sweden
- Centre for Clinical Research, Sörmland county council, Eskilstuna, Sweden
| | | | - Peter Aaby
- Projecto de Saúde de Bandim, Indepth Network, Bissau, Guinea-Bissau
| | - Poul-Erik Kofoed
- Projecto de Saúde de Bandim, Indepth Network, Bissau, Guinea-Bissau
- Department of Paediatrics, Kolding Hospital, Kolding, Denmark
- * E-mail: (JU); (P-EK)
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25
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Ch'ng JH, Lee YQ, Gun SY, Chia WN, Chang ZW, Wong LK, Batty KT, Russell B, Nosten F, Renia L, Tan KSW. Validation of a chloroquine-induced cell death mechanism for clinical use against malaria. Cell Death Dis 2014; 5:e1305. [PMID: 24967967 PMCID: PMC4611737 DOI: 10.1038/cddis.2014.265] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2013] [Revised: 04/04/2014] [Accepted: 05/20/2014] [Indexed: 01/09/2023]
Abstract
An alternative antimalarial pathway of an ‘outdated' drug, chloroquine (CQ), may facilitate its return to the shrinking list of effective antimalarials. Conventionally, CQ is believed to interfere with hemozoin formation at nanomolar concentrations, but resistant parasites are able to efflux this drug from the digestive vacuole (DV). However, we show that the DV membrane of both resistant and sensitive laboratory and field parasites is compromised after exposure to micromolar concentrations of CQ, leading to an extrusion of DV proteases. Furthermore, only a short period of exposure is required to compromise the viability of late-stage parasites. To study the feasibility of this strategy, mice malaria models were used to demonstrate that high doses of CQ also triggered DV permeabilization in vivo and reduced reinvasion efficiency. We suggest that a time-release oral formulation of CQ may sustain elevated blood CQ levels sufficiently to clear even CQ-resistant parasites.
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Affiliation(s)
- J-H Ch'ng
- 1] Department of Microbiology, National University of Singapore, 5 Science Drive 2, Singapore, Singapore [2] Department of Microbiology, Tumor and Cell Biology, Karolinska Institutet, Nobels väg 16, KI Solna Campus, Box 280, Stockholm, Sweden
| | - Y-Q Lee
- 1] Department of Microbiology, National University of Singapore, 5 Science Drive 2, Singapore, Singapore [2] NUS Graduate School for Integrative Sciences and Engineering, National University of Singapore, Centre for Life Sciences (CeLS), #05-01, 28 Medical Drive, Singapore, Singapore
| | - S Y Gun
- Singapore Immunology Network, Agency for Science Technology and Research (A*STAR), Biopolis, 8A Biomedical Grove, Immunos Building, Level 4, Singapore, Singapore
| | - W-N Chia
- Singapore Immunology Network, Agency for Science Technology and Research (A*STAR), Biopolis, 8A Biomedical Grove, Immunos Building, Level 4, Singapore, Singapore
| | - Z-W Chang
- Singapore Immunology Network, Agency for Science Technology and Research (A*STAR), Biopolis, 8A Biomedical Grove, Immunos Building, Level 4, Singapore, Singapore
| | - L-K Wong
- Department of Chemistry, National University of Singapore, Block S8, Level 3, 3 Science Drive 3, Singapore, Singapore
| | - K T Batty
- 1] School of Pharmacy, Curtin University, GPO Box U1987, Perth Western Australia 6845 Bentley, WA, Australia [2] West Coast Institute, 35 Kendrew Crescent, Joondalup, WA, Australia
| | - B Russell
- Department of Microbiology, National University of Singapore, 5 Science Drive 2, Singapore, Singapore
| | - F Nosten
- 1] Shoklo Malaria Research Unit, Mahidol-Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, 68/30 Bantung Road, PO.BOX 46, Maesot, TAK, Thailand [2] Centre for Tropical Medicine, Nuffield Department of Medicine, University of Oxford, Churchill Hospital, Old Road, Oxford, UK
| | - L Renia
- Singapore Immunology Network, Agency for Science Technology and Research (A*STAR), Biopolis, 8A Biomedical Grove, Immunos Building, Level 4, Singapore, Singapore
| | - K S-W Tan
- Department of Microbiology, National University of Singapore, 5 Science Drive 2, Singapore, Singapore
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26
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Antonia AL, Taylor SM, Janko M, Emch M, Tshefu AK, Meshnick SR. A cross-sectional survey of Plasmodium falciparum pfcrt mutant haplotypes in the Democratic Republic of Congo. Am J Trop Med Hyg 2014; 90:1094-7. [PMID: 24732459 DOI: 10.4269/ajtmh.13-0378] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
In the Democratic Republic of the Congo (DRC), artesunate-amodiaquine is first-line therapy for falciparum malaria; little is known about the prevalence of molecular markers of parasite drug resistance. Across the DRC, we genotyped 166 parasites in Plasmodium falciparum chloroquine resistance transporter (pfcrt) using polymerase chain reaction (PCR) and sequencing. Of these parasites, 73 (44%) parasites were pure wild-type CVMNK, 55 (31%) parasites were chloroquine-resistant CVIET: , 35 (21.1%) parasites were mixed CVMNK and CVIET: , and 3 parasites were other genotypes. Ninety-two infections (55.4%) harbored the pfcrt K76T: substitution that is highly correlated with chloroquine failure. The amodiaquine-resistant S: VMNT: haplotype was absent. Geographically, pfcrt haplotypes were not clearly clustered. Chloroquine accounted for 19.4% of antimalarial use, and amodiaquine accounted for 15.3% of antimalarial use; there were no associations between drug use and mutant haplotype prevalence. In the DRC, our molecular survey indicates that resistance to chloroquine is substantial but that resistance to amodiaquine is absent. These contrasting findings highlight the need for molecular surveillance of drug resistance to inform malaria control policies.
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Affiliation(s)
- Alejandro L Antonia
- Department of Epidemiology, Gillings School of Global Public Health, University of North Carolina, Chapel Hill, North Carolina; Division of Infectious Diseases and International Health, Duke University Medical Center, Durham, North Carolina; Department of Geography, University of North Carolina, Chapel Hill, North Carolina; Carolina Population Center, University of North Carolina, Chapel Hill, North Carolina; Ecole de Sante Publique, Faculte de Medicine, University of Kinshasa, Kinshasa, Democratic Republic of the Congo
| | - Steve M Taylor
- Department of Epidemiology, Gillings School of Global Public Health, University of North Carolina, Chapel Hill, North Carolina; Division of Infectious Diseases and International Health, Duke University Medical Center, Durham, North Carolina; Department of Geography, University of North Carolina, Chapel Hill, North Carolina; Carolina Population Center, University of North Carolina, Chapel Hill, North Carolina; Ecole de Sante Publique, Faculte de Medicine, University of Kinshasa, Kinshasa, Democratic Republic of the Congo
| | - Mark Janko
- Department of Epidemiology, Gillings School of Global Public Health, University of North Carolina, Chapel Hill, North Carolina; Division of Infectious Diseases and International Health, Duke University Medical Center, Durham, North Carolina; Department of Geography, University of North Carolina, Chapel Hill, North Carolina; Carolina Population Center, University of North Carolina, Chapel Hill, North Carolina; Ecole de Sante Publique, Faculte de Medicine, University of Kinshasa, Kinshasa, Democratic Republic of the Congo
| | - Michael Emch
- Department of Epidemiology, Gillings School of Global Public Health, University of North Carolina, Chapel Hill, North Carolina; Division of Infectious Diseases and International Health, Duke University Medical Center, Durham, North Carolina; Department of Geography, University of North Carolina, Chapel Hill, North Carolina; Carolina Population Center, University of North Carolina, Chapel Hill, North Carolina; Ecole de Sante Publique, Faculte de Medicine, University of Kinshasa, Kinshasa, Democratic Republic of the Congo
| | - Antoinette K Tshefu
- Department of Epidemiology, Gillings School of Global Public Health, University of North Carolina, Chapel Hill, North Carolina; Division of Infectious Diseases and International Health, Duke University Medical Center, Durham, North Carolina; Department of Geography, University of North Carolina, Chapel Hill, North Carolina; Carolina Population Center, University of North Carolina, Chapel Hill, North Carolina; Ecole de Sante Publique, Faculte de Medicine, University of Kinshasa, Kinshasa, Democratic Republic of the Congo
| | - Steven R Meshnick
- Department of Epidemiology, Gillings School of Global Public Health, University of North Carolina, Chapel Hill, North Carolina; Division of Infectious Diseases and International Health, Duke University Medical Center, Durham, North Carolina; Department of Geography, University of North Carolina, Chapel Hill, North Carolina; Carolina Population Center, University of North Carolina, Chapel Hill, North Carolina; Ecole de Sante Publique, Faculte de Medicine, University of Kinshasa, Kinshasa, Democratic Republic of the Congo
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Diverse mutational pathways converge on saturable chloroquine transport via the malaria parasite's chloroquine resistance transporter. Proc Natl Acad Sci U S A 2014; 111:E1759-67. [PMID: 24728833 DOI: 10.1073/pnas.1322965111] [Citation(s) in RCA: 53] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023] Open
Abstract
Mutations in the chloroquine resistance transporter (PfCRT) are the primary determinant of chloroquine (CQ) resistance in the malaria parasite Plasmodium falciparum. A number of distinct PfCRT haplotypes, containing between 4 and 10 mutations, have given rise to CQ resistance in different parts of the world. Here we present a detailed molecular analysis of the number of mutations (and the order of addition) required to confer CQ transport activity upon the PfCRT as well as a kinetic characterization of diverse forms of PfCRT. We measured the ability of more than 100 variants of PfCRT to transport CQ when expressed at the surface of Xenopus laevis oocytes. Multiple mutational pathways led to saturable CQ transport via PfCRT, but these could be separated into two main lineages. Moreover, the attainment of full activity followed a rigid process in which mutations had to be added in a specific order to avoid reductions in CQ transport activity. A minimum of two mutations sufficed for (low) CQ transport activity, and as few as four conferred full activity. The finding that diverse PfCRT variants are all limited in their capacity to transport CQ suggests that resistance could be overcome by reoptimizing the CQ dosage.
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28
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Hastings IM, Hodel EM. Pharmacological considerations in the design of anti-malarial drug combination therapies - is matching half-lives enough? Malar J 2014; 13:62. [PMID: 24552440 PMCID: PMC3975950 DOI: 10.1186/1475-2875-13-62] [Citation(s) in RCA: 21] [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: 12/13/2013] [Accepted: 02/15/2014] [Indexed: 11/20/2022] Open
Abstract
Anti-malarial drugs are now mainly deployed as combination therapy (CT), primarily as a mechanism to prevent or slow the spread of resistance. This strategy is justified by mathematical arguments that generally assume that drug 'resistance' is a binary all-or-nothing genetic trait. Herein, a pharmacological, rather than a purely genetic, approach is used to investigate resistance and it is argued that this provides additional insight into the design principles of anti-malarial CTs. It is usually suggested that half-lives of constituent drugs in a CT be matched: it appears more important that their post-treatment anti-malarial activity profiles be matched and strategies identified that may achieve this. In particular, the considerable variation in pharmacological parameters noted in both human and parasites populations may compromise this matching and it is, therefore, essential to accurately quantify the population pharmacokinetics of the drugs in the CTs. Increasing drug dosages will likely follow a law of diminishing returns in efficacy, i.e. a certain increase in dose will not necessarily lead to the same percent increase in efficacy. This may allow individual drug dosages to be lowered without proportional decrease in efficacy, reducing any potential toxicity, and allowing the other drug(s) in the CT to compensate for this reduced dosage; this is a dangerous strategy which is discussed further. Finally, pharmacokinetic and pharmacodynamic drug interactions and the role of resistance mechanisms are discussed. This approach generated an idealized target product profile (TPP) for anti-malarial CTs. There is a restricted pipeline of anti-malarial drugs but awareness of pharmacological design principles during the development stages could optimize CT design pre-deployment. This may help prevent changes in drug dosages and/or regimen that have previously occurred post-deployment in most current anti-malarial drugs.
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Affiliation(s)
- Ian M Hastings
- Liverpool School of Tropical Medicine, Pembroke Place, Liverpool L3 5QA, UK
| | - Eva Maria Hodel
- Liverpool School of Tropical Medicine, Pembroke Place, Liverpool L3 5QA, UK
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29
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Ursing J, Eksborg S, Rombo L, Bergqvist Y, Blessborn D, Rodrigues A, Kofoed PE. Chloroquine is grossly under dosed in young children with malaria: implications for drug resistance. PLoS One 2014; 9:e86801. [PMID: 24466245 PMCID: PMC3900653 DOI: 10.1371/journal.pone.0086801] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2013] [Accepted: 12/13/2013] [Indexed: 01/09/2023] Open
Abstract
Background Plasmodium falciparum malaria is treated with 25 mg/kg of chloroquine (CQ) irrespective of age. Theoretically, CQ should be dosed according to body surface area (BSA). The effect of dosing CQ according to BSA has not been determined but doubling the dose per kg doubled the efficacy of CQ in children aged <15 years infected with P. falciparum carrying CQ resistance causing genes typical for Africa. The study aim was to determine the effect of age on CQ concentrations. Methods and Findings Day 7 whole blood CQ concentrations were determined in 150 and 302 children treated with 25 and 50 mg/kg, respectively, in previously conducted clinical trials. CQ concentrations normalised for the dose taken in mg/kg of CQ decreased with decreasing age (p<0.001). CQ concentrations normalised for dose taken in mg/m2 were unaffected by age. The median CQ concentration in children aged <2 years taking 50 mg/kg and in children aged 10–14 years taking 25 mg/kg were 825 (95% confidence interval [CI] 662–988) and 758 (95% CI 640–876) nmol/l, respectively (p = 0.67). The median CQ concentration in children aged 10–14 taking 50 mg/kg and children aged 0–2 taking 25 mg/kg were 1521 and 549 nmol/l. Adverse events were not age/concentration dependent. Conclusions CQ is under-dosed in children and should ideally be dosed according to BSA. Children aged <2 years need approximately double the dose per kg to attain CQ concentrations found in children aged 10–14 years. Clinical trials assessing the efficacy of CQ in Africa are typically performed in children aged <5 years. Thus the efficacy of CQ is typically assessed in children in whom CQ is under dosed. Approximately 3 fold higher drug concentrations can probably be safely given to the youngest children. As CQ resistance is concentration dependent an alternative dosing of CQ may overcome resistance in Africa.
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Affiliation(s)
- Johan Ursing
- Projecto de Saúde de Bandim, Indepth Network, Bissau, Guinea-Bissau
- Malaria Research Laboratory, Department of Medicine, Karolinska University Hospital, Karolinska Institutet, Stockholm, Sweden
- * E-mail:
| | - Staffan Eksborg
- Department of Women’s and Children’s Health, Childhood Cancer Research Unit, Karolinska Institutet, Stockholm, Sweden
| | - Lars Rombo
- Malaria Research Laboratory, Department of Medicine, Karolinska University Hospital, Karolinska Institutet, Stockholm, Sweden
- Centre for Clinical Research, Sörmland, Uppsala University, Sweden
| | | | - Daniel Blessborn
- Mahidol Oxford Research Unit, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand
- Centre for Tropical Medicine, Nuffield Department of Clinical Medicine, University of Oxford, Oxford, United Kingdom
| | | | - Poul-Erik Kofoed
- Projecto de Saúde de Bandim, Indepth Network, Bissau, Guinea-Bissau
- Department of Paediatrics, Kolding Hospital, Kolding, Denmark
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PfCRT and its role in antimalarial drug resistance. Trends Parasitol 2012; 28:504-14. [PMID: 23020971 DOI: 10.1016/j.pt.2012.08.002] [Citation(s) in RCA: 185] [Impact Index Per Article: 15.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2012] [Revised: 08/09/2012] [Accepted: 08/13/2012] [Indexed: 12/15/2022]
Abstract
Plasmodium falciparum resistance to chloroquine, the former gold standard antimalarial drug, is mediated primarily by mutant forms of the chloroquine resistance transporter (PfCRT). These mutations impart upon PfCRT the ability to efflux chloroquine from the intracellular digestive vacuole, the site of drug action. Recent studies reveal that PfCRT variants can also affect parasite fitness, protect immature gametocytes against chloroquine action, and alter P. falciparum susceptibility to current first-line therapies. These results highlight the need to be vigilant in screening for the appearance of novel pfcrt alleles that could contribute to new multi-drug resistance phenotypes.
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Summers RL, Nash MN, Martin RE. Know your enemy: understanding the role of PfCRT in drug resistance could lead to new antimalarial tactics. Cell Mol Life Sci 2012; 69:1967-95. [PMID: 22286067 PMCID: PMC11115045 DOI: 10.1007/s00018-011-0906-0] [Citation(s) in RCA: 57] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2011] [Revised: 11/22/2011] [Accepted: 12/06/2011] [Indexed: 10/14/2022]
Abstract
The prevention and treatment of malaria is heavily dependent on antimalarial drugs. However, beginning with the emergence of chloroquine (CQ)-resistant Plasmodium falciparum parasites 50 years ago, efforts to control the disease have been thwarted by failed or failing drugs. Mutations in the parasite's 'chloroquine resistance transporter' (PfCRT) are the primary cause of CQ resistance. Furthermore, changes in PfCRT (and in several other transport proteins) are associated with decreases or increases in the parasite's susceptibility to a number of other antimalarial drugs. Here, we review recent advances in our understanding of CQ resistance and discuss these in the broader context of the parasite's susceptibilities to other quinolines and related drugs. We suggest that PfCRT can be viewed both as a 'multidrug-resistance carrier' and as a drug target, and that the quinoline-resistance mechanism is a potential 'Achilles' heel' of the parasite. We examine a number of the antimalarial strategies currently undergoing development that are designed to exploit the resistance mechanism, including relatively simple measures, such as alternative CQ dosages, as well as new drugs that either circumvent the resistance mechanism or target it directly.
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Affiliation(s)
- Robert L. Summers
- Research School of Biology, The Australian National University, Canberra, ACT 0200 Australia
| | - Megan N. Nash
- Research School of Biology, The Australian National University, Canberra, ACT 0200 Australia
| | - Rowena E. Martin
- Research School of Biology, The Australian National University, Canberra, ACT 0200 Australia
- School of Botany, University of Melbourne, Parkville, VIC 3010 Australia
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Stover KR, King ST, Robinson J. Artemether-lumefantrine: an option for malaria. Ann Pharmacother 2012; 46:567-77. [PMID: 22496476 DOI: 10.1345/aph.1q539] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022] Open
Abstract
OBJECTIVE To review the pharmacology, pharmacokinetics, safety, and efficacy of artemether-lumefantrine for the treatment of Plasmodium falciparum malaria. DATA SOURCES English-language articles indexed in PubMed (1947-November 2011) were identified, using the search terms artemether-lumefantrine, artemether-lumefantrine AND malaria, Coartem, and Coartem AND malaria. STUDY SELECTION AND DATA EXTRACTION Available English-language articles were reviewed. In addition, the malaria treatment regimens recommended by region as provided by the World Health Organization and the treatment guidelines from the Centers for Disease Control and Prevention were reviewed. DATA SYNTHESIS Artemether-lumefantrine is an artemisinin-derived combination antimalarial approved by the Food and Drug Administration in 2009 for the treatment of P. falciparum malaria. The dual mechanisms of action of artemether-lumefantrine provide rapid and sustained parasite clearance. In the reviewed studies, the polymerase chain reaction (PCR)-corrected 28-day cure rates of artemether-lumefantrine were noninferior to the most common comparators, including chloroquine, dapsone, and other artemisinin derivatives (86-100% vs 51-100%, respectively). PCR-corrected day-42 cure rates were 92-99.3% for artemether-lumefantrine versus 62-100% for the comparator groups. The major adverse effects (gastrointestinal and central nervous system) were mild to moderate in severity and did not require a change in therapy. Although adherence to artemether-lumefantrine has been described as a potential problem due to the complicated dosing schedule, studies have described clinical cure rates similar to those of other antimalarials. CONCLUSIONS Artemether-lumefantrine is a safe and effective treatment for children and adults with P. falciparum malaria.
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Affiliation(s)
- Kayla R Stover
- School of Pharmacy, University of Mississippi, Jackson, MS, USA.
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Saquinavir inhibits the malaria parasite's chloroquine resistance transporter. Antimicrob Agents Chemother 2012; 56:2283-9. [PMID: 22354298 DOI: 10.1128/aac.00166-12] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The antiretroviral protease inhibitors (APIs) ritonavir, saquinavir, and lopinavir, used to treat HIV infection, inhibit the growth of Plasmodium falciparum at clinically relevant concentrations. Moreover, it has been reported that these APIs potentiate the activity of chloroquine (CQ) against this parasite in vitro. The mechanism underlying this effect is not understood, but the degree of chemosensitization varies between the different APIs and, with the exception of ritonavir, appears to be dependent on the parasite exhibiting a CQ-resistant phenotype. Here we report a study of the role of the P. falciparum chloroquine resistance transporter (PfCRT) in the interaction between CQ and APIs, using transgenic parasites expressing different PfCRT alleles and using the Xenopus laevis oocyte system for the heterologous expression of PfCRT. Our data demonstrate that saquinavir behaves as a CQ resistance reverser and that this explains, at least in part, its ability to enhance the effects of CQ in CQ-resistant P. falciparum parasites.
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Sutherland CJ, Babiker H, Mackinnon MJ, Ranford-Cartwright L, El Sayed BB. Rational deployment of antimalarial drugs in Africa: should first-line combination drugs be reserved for paediatric malaria cases? Parasitology 2011; 138:1459-68. [PMID: 21810298 PMCID: PMC3575203 DOI: 10.1017/s0031182011001144] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
Artemisinin-based combination therapy is exerting novel selective pressure upon populations of Plasmodium falciparum across Africa. Levels of resistance to non-artemisinin partner drugs differ among parasite populations, and so the artemisinins are not uniformly protected from developing resistance, already present in South East Asia. Here, we consider strategies for prolonging the period of high level efficacy of combination therapy for two particular endemicities common in Africa. Under high intensity transmission, two alternating first-line combinations, ideally with antagonistic selective effects on the parasite genome, are advocated for paediatric malaria cases. This leaves second-line and other therapies for adult cases, and for intermittent preventive therapy. The drug portfolio would be selected to protect the 'premier' combination regimen from selection for resistance, while maximising impact on severe disease and mortality in children. In endemic areas subject to low, seasonal transmission of Plasmodium falciparum, such a strategy may deliver little benefit, as children represent a minority of cases. Nevertheless, the deployment of other drug-based interventions in low transmission and highly seasonal areas, such as mass drug administration aimed to interrupt malaria transmission, or intermittent preventive therapy, does provide an opportunity to diversify drug pressure. We thus propose an integrated approach to drug deployment, which minimises direct selective pressure on parasite populations from any one drug component. This approach is suitable for qualitatively and quantitatively different burdens of malaria, and should be supported by a programme of routine surveillance for emerging resistance.
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Affiliation(s)
- Colin J Sutherland
- Department of Immunology & Infection, Faculty of Infectious & Tropical Diseases, London School of Hygiene & Tropical Medicine, London, WC1E 7HT, UK.
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Chico RM, Chandramohan D. Azithromycin plus chloroquine: combination therapy for protection against malaria and sexually transmitted infections in pregnancy. Expert Opin Drug Metab Toxicol 2011; 7:1153-67. [PMID: 21736423 PMCID: PMC3170143 DOI: 10.1517/17425255.2011.598506] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
Introduction: The first-line therapy for the intermittent preventive treatment of malaria in pregnancy (IPTp) is sulphadoxine-pyrimethamine (SP). There is an urgent need to identify safe, well-tolerated and efficacious alternatives to SP due to widespread Plasmodium falciparum resistance. Combination therapy using azithromycin and chloroquine is one possibility that has demonstrated adequate parasitological response > 95% in clinical trials of non-pregnant adults in sub-Saharan Africa and where IPTp is a government policy in 33 countries. Areas covered: Key safety, tolerability and efficacy data are presented for azithromycin and chloroquine, alone and/or in combination, when used to prevent and/or treat P. falciparum, P. vivax, and several curable sexually transmitted and reproductive tract infections (STI/RTI). Pharmacokinetic evidence from pregnant women is also summarized for both compounds. Expert opinion: The azithromycin-chloroquine regimen that has demonstrated consistent efficacy in non-pregnant adults has been a 3-day course containing daily doses of 1 g of azithromycin and 600 mg base of chloroquine. The pharmacokinetic evidence of these compounds individually suggests that dose adjustments may not be necessary when used in combination for treatment efficacy against P. falciparum, P. vivax, as well as several curable STI/ RTI among pregnant women, although clinical confirmation will be necessary. Mass trachoma-treatment campaigns have shown that azithromycin selects for macrolide resistance in the pneumococcus, which reverses following the completion of therapy. Most importantly, no evidence to date suggests that azithromycin induces pneumococcal resistance to penicillin.
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Affiliation(s)
- R Matthew Chico
- London School of Hygiene and Tropical Medicine, Faculty of Infectious and Tropical Diseases, Disease Control Department, UK.
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Pharmacokinetics, pharmacodynamics, and allometric scaling of chloroquine in a murine malaria model. Antimicrob Agents Chemother 2011; 55:3899-907. [PMID: 21646487 DOI: 10.1128/aac.00067-11] [Citation(s) in RCA: 54] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Chloroquine (CQ) is an important antimalarial drug for the treatment of special patient groups and as a comparator for preclinical testing of new drugs. Pharmacokinetic data for CQ in animal models are limited; thus, we conducted a three-part investigation, comprising (i) pharmacodynamic studies of CQ and CQ plus dihydroartemisinin (DHA) in Plasmodium berghei-infected mice, (ii) pharmacokinetic studies of CQ in healthy and malaria-infected mice, and (iii) interspecies allometric scaling for CQ from 6 animal and 12 human studies. The single-dose pharmacodynamic study (10 to 50 mg CQ/kg of body weight) showed dose-related reduction in parasitemia (5- to >500-fold) and a nadir 2 days after the dose. Multiple-dose regimens (total dose, 50 mg/kg CQ) demonstrated a lower nadir and longer survival time than did the same single dose. The CQ-DHA combination provided an additive effect compared to each drug alone. The elimination half-life (t(1/2)), clearance (CL), and volume of distribution (V) of CQ were 46.6 h, 9.9 liters/h/kg, and 667 liters/kg, respectively, in healthy mice and 99.3 h, 7.9 liters/h/kg, and 1,122 liters/kg, respectively, in malaria-infected mice. The allometric equations for CQ in healthy mammals (CL = 3.86 × W(0.56), V = 230 × W(0.94), and t(1/2) = 123 × W(0.2)) were similar to those for malaria-infected groups. CQ showed a delayed dose-response relationship in the murine malaria model and additive efficacy when combined with DHA. The biphasic pharmacokinetic profiles of CQ are similar across mammalian species, and scaling of specific parameters is plausible for preclinical investigations.
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