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Christensen P, Cinzah R, Suwanarusk R, Chua ACY, Kaneko O, Kyle DE, Aung HL, Matheson J, Bifani P, Rénia L, Cook GM, Snounou G, Russell B. Extended blood stage sensitivity profiles of Plasmodium cynomolgi to doxycycline and tafenoquine, as a model for Plasmodium vivax. Antimicrob Agents Chemother 2024; 68:e0028024. [PMID: 38587391 PMCID: PMC11064600 DOI: 10.1128/aac.00280-24] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2024] [Accepted: 03/15/2024] [Indexed: 04/09/2024] Open
Abstract
Testing Plasmodium vivax antimicrobial sensitivity is limited to ex vivo schizont maturation assays, which preclude determining the IC50s of delayed action antimalarials such as doxycycline. Using Plasmodium cynomolgi as a model for P. vivax, we determined the physiologically significant delayed death effect induced by doxycycline [IC50(96 h), 1,401 ± 607 nM]. As expected, IC50(96 h) to chloroquine (20.4 nM), piperaquine (12.6 µM), and tafenoquine (1,424 nM) were not affected by extended exposure.
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Affiliation(s)
- Peter Christensen
- Department of Microbiology and Immunology, University of Otago, Dunedin, New Zealand
- Maurice Wilkins Centre for Molecular Biodiscovery, University of Auckland, Auckland, New Zealand
| | - Rosy Cinzah
- Department of Microbiology and Immunology, University of Otago, Dunedin, New Zealand
| | - Rossarin Suwanarusk
- Department of Microbiology and Immunology, University of Otago, Dunedin, New Zealand
| | - Adeline Chiew Yen Chua
- A*STAR Infectious Diseases Labs, Agency for Science, Technology and Research (A*STAR), , Singapore
| | - Osamu Kaneko
- Department of Protozoology, Institute of Tropical Medicine (NEKKEN), Nagasaki University, Sakamoto, Nagasaki, Japan
| | - Dennis E. Kyle
- Center for Tropical and Emerging Global Diseases, University of Georgia, Athens, Georgia, USA
| | - Htin Lin Aung
- Department of Microbiology and Immunology, University of Otago, Dunedin, New Zealand
- Maurice Wilkins Centre for Molecular Biodiscovery, University of Auckland, Auckland, New Zealand
| | - Jessica Matheson
- Department of Microbiology and Immunology, University of Otago, Dunedin, New Zealand
| | - Pablo Bifani
- Lee Kong Chian School of Medicine, Nanyang Technological University, Singapore
| | - Laurent Rénia
- A*STAR Infectious Diseases Labs, Agency for Science, Technology and Research (A*STAR), , Singapore
- Lee Kong Chian School of Medicine, Nanyang Technological University, Singapore
| | - Gregory M. Cook
- Department of Microbiology and Immunology, University of Otago, Dunedin, New Zealand
- Maurice Wilkins Centre for Molecular Biodiscovery, University of Auckland, Auckland, New Zealand
| | - Georges Snounou
- 11-Université Paris-Saclay, Inserm, CEA, Immunologie des maladies virales, auto-immunes, hématologiques et bactériennes (IMVA-HB/IDMIT/UMR1184), Fontenay-aux-Roses & Kremlin- Bicêtre, Le Kremlin-Bicêtre, France
| | - Bruce Russell
- Department of Microbiology and Immunology, University of Otago, Dunedin, New Zealand
- Department of Protozoology, Institute of Tropical Medicine (NEKKEN), Nagasaki University, Sakamoto, Nagasaki, Japan
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2
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Umumararungu T, Nkuranga JB, Habarurema G, Nyandwi JB, Mukazayire MJ, Mukiza J, Muganga R, Hahirwa I, Mpenda M, Katembezi AN, Olawode EO, Kayitare E, Kayumba PC. Recent developments in antimalarial drug discovery. Bioorg Med Chem 2023; 88-89:117339. [PMID: 37236020 DOI: 10.1016/j.bmc.2023.117339] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2023] [Revised: 05/12/2023] [Accepted: 05/16/2023] [Indexed: 05/28/2023]
Abstract
Although malaria remains a big burden to many countries that it threatens their socio-economic stability, particularly in the countries where malaria is endemic, there have been great efforts to eradicate this disease with both successes and failures. For example, there has been a great improvement in malaria prevention and treatment methods with a net reduction in infection and mortality rates. However, the disease remains a global threat in terms of the number of people affected because it is one of the infectious diseases that has the highest prevalence rate, especially in Africa where the deadly Plasmodium falciparum is still widely spread. Methods to fight malaria are being diversified, including the use of mosquito nets, the target candidate profiles (TCPs) and target product profiles (TPPs) of medicine for malarial venture (MMV) strategy, the search for newer and potent drugs that could reverse chloroquine resistance, and the use of adjuvants such as rosiglitazone and sevuparin. Although these adjuvants have no antiplasmodial activity, they can help to alleviate the effects which result from plasmodium invasion such as cytoadherence. The list of new antimalarial drugs under development is long, including the out of ordinary new drugs MMV048, CDRI-97/78 and INE963 from South Africa, India and Novartis, respectively.
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Affiliation(s)
- Théoneste Umumararungu
- Department of Pharmacy, School of Medicine and Pharmacy, College of Medicine and Health Sciences, University of Rwanda, Rwanda.
| | - Jean Bosco Nkuranga
- Department of Chemistry, School of Science, College of Science and Technology, University of Rwanda, Rwanda
| | - Gratien Habarurema
- Department of Chemistry, School of Science, College of Science and Technology, University of Rwanda, Rwanda
| | - Jean Baptiste Nyandwi
- Department of Pharmacy, School of Medicine and Pharmacy, College of Medicine and Health Sciences, University of Rwanda, Rwanda
| | - Marie Jeanne Mukazayire
- Department of Pharmacy, School of Medicine and Pharmacy, College of Medicine and Health Sciences, University of Rwanda, Rwanda
| | - Janvier Mukiza
- Department of Mathematical Science and Physical Education, School of Education, College of Education, University of Rwanda, Rwanda; Rwanda Food and Drugs Authority, Nyarutarama Plaza, KG 9 Avenue, Kigali, Rwanda
| | - Raymond Muganga
- Department of Pharmacy, School of Medicine and Pharmacy, College of Medicine and Health Sciences, University of Rwanda, Rwanda; Rwanda Food and Drugs Authority, Nyarutarama Plaza, KG 9 Avenue, Kigali, Rwanda
| | - Innocent Hahirwa
- Department of Pharmacy, School of Medicine and Pharmacy, College of Medicine and Health Sciences, University of Rwanda, Rwanda
| | - Matabishi Mpenda
- Department of Pharmacy, School of Medicine and Pharmacy, College of Medicine and Health Sciences, University of Rwanda, Rwanda
| | - Alain Nyirimigabo Katembezi
- Department of Pharmacy, School of Medicine and Pharmacy, College of Medicine and Health Sciences, University of Rwanda, Rwanda; Rwanda Food and Drugs Authority, Nyarutarama Plaza, KG 9 Avenue, Kigali, Rwanda
| | - Emmanuel Oladayo Olawode
- Department of Pharmaceutical Sciences, College of Pharmacy, Larkin University, 18301 N Miami Ave #1, Miami, FL 33169, USA
| | - Egide Kayitare
- Department of Pharmacy, School of Medicine and Pharmacy, College of Medicine and Health Sciences, University of Rwanda, Rwanda
| | - Pierre Claver Kayumba
- Department of Pharmacy, School of Medicine and Pharmacy, College of Medicine and Health Sciences, University of Rwanda, Rwanda
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3
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Markus MB. Putative Contribution of 8-Aminoquinolines to Preventing Recrudescence of Malaria. Trop Med Infect Dis 2023; 8:278. [PMID: 37235326 PMCID: PMC10223033 DOI: 10.3390/tropicalmed8050278] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2023] [Revised: 05/07/2023] [Accepted: 05/12/2023] [Indexed: 05/28/2023] Open
Abstract
Enhanced therapeutic efficacy achieved in treating Plasmodium vivax malaria with an 8-aminoquinoline (8-AQ) drug such as primaquine (PQ) together with a partner drug such as chloroquine (CQ) is usually explained as CQ inhibiting asexual parasites in the bloodstream and PQ acting against liver stages. However, PQ's contribution, if any, to inactivating non-circulating, extra-hepatic asexual forms, which make up the bulk of the parasite biomass in chronic P. vivax infections, remains unclear. In this opinion article, I suggest that, considering its newly described mode of action, PQ might be doing something of which we are currently unaware.
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Affiliation(s)
- Miles B. Markus
- Wits Research Institute for Malaria, School of Pathology, Faculty of Health Sciences, University of Witwatersrand, Johannesburg 2193, South Africa;
- School of Animal, Plant and Environmental Sciences, Faculty of Science, University of Witwatersrand, Johannesburg 2001, South Africa
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4
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Van de Walle T, Cools L, Mangelinckx S, D'hooghe M. Recent contributions of quinolines to antimalarial and anticancer drug discovery research. Eur J Med Chem 2021; 226:113865. [PMID: 34655985 DOI: 10.1016/j.ejmech.2021.113865] [Citation(s) in RCA: 24] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2021] [Revised: 09/01/2021] [Accepted: 09/20/2021] [Indexed: 12/28/2022]
Abstract
Quinoline, a privileged scaffold in medicinal chemistry, has always been associated with a multitude of biological activities. Especially in antimalarial and anticancer research, quinoline played (and still plays) a central role, giving rise to the development of an array of quinoline-containing pharmaceuticals in these therapeutic areas. However, both diseases still affect millions of people every year, pointing to the necessity of new therapies. Quinolines have a long-standing history as antimalarial agents, but established quinoline-containing antimalarial drugs are now facing widespread resistance of the Plasmodium parasite. Nevertheless, as evidenced by a massive number of recent literature contributions, they are still of great value for future developments in this field. On the other hand, the number of currently approved anticancer drugs containing a quinoline scaffold are limited, but a strong increase and interest in quinoline compounds as potential anticancer agents can be seen in the last few years. In this review, a literature overview of recent contributions made by quinoline-containing compounds as potent antimalarial or anticancer agents is provided, covering publications between 2018 and 2020.
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Affiliation(s)
- Tim Van de Walle
- SynBioC Research Group, Department of Green Chemistry and Technology, Faculty of Bioscience Engineering, Ghent University, Coupure Links 653, B-9000, Ghent, Belgium
| | - Lore Cools
- SynBioC Research Group, Department of Green Chemistry and Technology, Faculty of Bioscience Engineering, Ghent University, Coupure Links 653, B-9000, Ghent, Belgium
| | - Sven Mangelinckx
- SynBioC Research Group, Department of Green Chemistry and Technology, Faculty of Bioscience Engineering, Ghent University, Coupure Links 653, B-9000, Ghent, Belgium
| | - Matthias D'hooghe
- SynBioC Research Group, Department of Green Chemistry and Technology, Faculty of Bioscience Engineering, Ghent University, Coupure Links 653, B-9000, Ghent, Belgium.
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5
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Val F, Costa FT, King L, Brito-Sousa JD, Bassat Q, Monteiro WM, Siqueira AM, Luzzatto L, Lacerda MV. Tafenoquine for the prophylaxis, treatment and elimination of malaria: eagerness must meet prudence. Future Microbiol 2019; 14:1261-1279. [PMID: 31596137 DOI: 10.2217/fmb-2019-0202] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022] Open
Abstract
Malaria puts more than 3 billion people at risk of infection and causes high morbidity and mortality. Plasmodium vivax forms hypnozoites, which may initiate recurrences, even in the absence of reinfection or superinfection. Until recently, the only drug available for eliminating hypnozoites was primaquine (PQ), which, given its short half-life, requires a relatively long course of treatment. Tafenoquine (TQ) is a PQ analog with a longer half-life. This enables radical cure of malaria with a single dose and overcomes adherence issues associated with PQ, thereby increasing effectiveness in real-life settings. Clinical studies have provided sound evidence for TQ's safety and efficacy against malaria, which recently led to its approval by the US FDA. Here, we review aspects of TQ, including how to avoid hemolytic anemia in G6PD deficient patients. We believe that TQ promises to be a major advance toward malaria elimination.
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Affiliation(s)
- Fernando Val
- Fundação de Medicina Tropical Doutor Heitor Vieira Dourado, Manaus, Amazonas, 69040-000, Brazil
| | - Fabio Tm Costa
- Universidade Estadual de Campinas (UNICAMP), Campinas, São Paulo, 13083-970, Brazil
| | - Liam King
- The Scripps Research Institute, La Jolla, CA 92037, USA
| | - Jose D Brito-Sousa
- Fundação de Medicina Tropical Doutor Heitor Vieira Dourado, Manaus, Amazonas, 69040-000, Brazil.,Escola Superior de Ciências da Saúde,Universidade do Estado do Amazonas, Manaus, Amazonas, 69065-001, Brazil
| | - Quique Bassat
- ISGlobal, Hospital Clínic - Universitat de Barcelona, Barcelona, 08036, Spain.,Centro de Investigação em Saúde de Manhiça (CISM), Distrito da Manhiça, CP 1929, Maputo, Mozambique.,ICREA, Pg. Lluís Companys 23, Barcelona, 08010, Spain.,Pediatric Infectious Diseases Unit, Pediatrics Department, Hospital Sant Joan de Déu (University of Barcelona), Barcelona, 08950, Spain
| | - Wuelton M Monteiro
- Fundação de Medicina Tropical Doutor Heitor Vieira Dourado, Manaus, Amazonas, 69040-000, Brazil.,Escola Superior de Ciências da Saúde,Universidade do Estado do Amazonas, Manaus, Amazonas, 69065-001, Brazil
| | - André M Siqueira
- Instituto Nacional de Infectologia Evandro Chagas, Fundação Oswaldo Cruz, Rio de Janeiro, Rio de Janeiro, 21040-360, Brazil
| | - Lucio Luzzatto
- Department of Hematology & Blood Transfusion, Muhimbili University of Health & Allied Sciences, Dar-es-Salaam, Tanzania
| | - Marcus Vg Lacerda
- Fundação de Medicina Tropical Doutor Heitor Vieira Dourado, Manaus, Amazonas, 69040-000, Brazil.,Instituto Leônidas e Maria Deane, FIOCRUZ-AM, Manaus, Amazonas, 69057-070, Brazil
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6
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von Seidlein L, Peto TJ, Tripura R, Pell C, Yeung S, Kindermans JM, Dondorp A, Maude R. Novel Approaches to Control Malaria in Forested Areas of Southeast Asia. Trends Parasitol 2019; 35:388-398. [PMID: 31076353 DOI: 10.1016/j.pt.2019.03.011] [Citation(s) in RCA: 27] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2019] [Revised: 03/24/2019] [Accepted: 03/27/2019] [Indexed: 12/27/2022]
Abstract
The emergence and spread of drug resistance in the Greater Mekong Subregion (GMS) have added urgency to accelerate malaria elimination while reducing the treatment options. The remaining foci of malaria transmission are often in forests, where vectors tend to bite during daytime and outdoors, thus reducing the effectiveness of insecticide-treated bed nets. Limited periods of exposure suggest that chemoprophylaxis could be a promising strategy to protect forest workers against malaria. Here we discuss three major questions in optimizing malaria chemoprophylaxis for forest workers: which antimalarial drug regimens are most appropriate, how frequently the chemoprophylaxis should be delivered, and how to motivate forest workers to use, and adhere to, malaria prophylaxis.
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Affiliation(s)
- Lorenz von Seidlein
- Mahidol Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand; Centre for Tropical Medicine and Global Health, Nuffield Department of Medicine, University of Oxford, Oxford, UK.
| | - Thomas J Peto
- Mahidol Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand; Centre for Tropical Medicine and Global Health, Nuffield Department of Medicine, University of Oxford, Oxford, UK
| | - Rupam Tripura
- Mahidol Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand; Centre for Tropical Medicine and Global Health, Nuffield Department of Medicine, University of Oxford, Oxford, UK
| | - Christopher Pell
- Centre for Social Sciences and Global Health, University of Amsterdam, Amsterdam, The Netherlands; Amsterdam Institute for Global Health and Development, Amsterdam, The Netherlands
| | - Shunmay Yeung
- London School of Hygiene and Tropical Medicine, London, UK
| | | | - Arjen Dondorp
- Mahidol Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand; Centre for Tropical Medicine and Global Health, Nuffield Department of Medicine, University of Oxford, Oxford, UK
| | - Richard Maude
- Mahidol Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand; Centre for Tropical Medicine and Global Health, Nuffield Department of Medicine, University of Oxford, Oxford, UK; Harvard T.H. Chan School of Public Health, Harvard University, Boston, MA, USA
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7
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Leven M, Held J, Duffy S, Alves Avelar LA, Meister S, Delves M, Plouffe D, Kuna K, Tschan S, Avery VM, Winzeler EA, Mordmüller B, Kurz T. 8-Aminoquinolines with an Aminoxyalkyl Side Chain Exert in vitro Dual-Stage Antiplasmodial Activity. ChemMedChem 2019; 14:501-511. [PMID: 30605243 DOI: 10.1002/cmdc.201800691] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2018] [Revised: 12/13/2018] [Indexed: 12/29/2022]
Abstract
A series of novel 8-aminoquinolines (8-AQs) with an aminoxyalkyl side chain were synthesized and evaluated for in vitro antiplasmodial properties against asexual blood stages, liver stages, and sexual stages of Plasmodium falciparum. 8-AQs bearing 2-alkoxy and 5-phenoxy substituents on the quinoline ring system were found to be the most promising compounds under study, exhibiting potent blood schizontocidal and moderate tissue schizontocidal in vitro activity.
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Affiliation(s)
- Michael Leven
- Institut für Pharmazeutische und Medizinische Chemie, Heinrich-Heine-Universität Düsseldorf, Universitätsstrasse 1, 40225, Düsseldorf, Germany
| | - Jana Held
- Institut für Tropenmedizin, Eberhard Karls Universität Tübingen, Wilhelmstrasse 27, 72074, Tübingen, Germany
| | - Sandra Duffy
- Eskitis Institute for Drug Discovery, Griffith University, Brisbane Innovation Park Campus, Nathan, QLD, 4111, Australia
| | - Leandro A Alves Avelar
- Institut für Pharmazeutische und Medizinische Chemie, Heinrich-Heine-Universität Düsseldorf, Universitätsstrasse 1, 40225, Düsseldorf, Germany
| | - Stephan Meister
- Department of Pediatrics, University of California San Diego, 9500 Gilman Drive, La Jolla, CA, 92037, USA
| | - Michael Delves
- Department of Life Sciences, Imperial College London, London, SW7 2AZ, UK
| | - David Plouffe
- Genomics Institute of the Novartis Research Foundation Department, Novartis, 10675 John Jay Hopkins Drive, San Diego, CA, 92121, USA
| | - Krystina Kuna
- Institut für Pharmazeutische und Medizinische Chemie, Heinrich-Heine-Universität Düsseldorf, Universitätsstrasse 1, 40225, Düsseldorf, Germany
| | - Serena Tschan
- Institut für Tropenmedizin, Eberhard Karls Universität Tübingen, Wilhelmstrasse 27, 72074, Tübingen, Germany
| | - Vicky M Avery
- Eskitis Institute for Drug Discovery, Griffith University, Brisbane Innovation Park Campus, Nathan, QLD, 4111, Australia
| | - Elizabeth A Winzeler
- Department of Pediatrics, University of California San Diego, 9500 Gilman Drive, La Jolla, CA, 92037, USA
| | - Benjamin Mordmüller
- Institut für Tropenmedizin, Eberhard Karls Universität Tübingen, Wilhelmstrasse 27, 72074, Tübingen, Germany
| | - Thomas Kurz
- Institut für Pharmazeutische und Medizinische Chemie, Heinrich-Heine-Universität Düsseldorf, Universitätsstrasse 1, 40225, Düsseldorf, Germany
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8
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Dow G, Smith B. The blood schizonticidal activity of tafenoquine makes an essential contribution to its prophylactic efficacy in nonimmune subjects at the intended dose (200 mg). Malar J 2017; 16:209. [PMID: 28526056 PMCID: PMC5438551 DOI: 10.1186/s12936-017-1862-4] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/26/2016] [Accepted: 05/13/2017] [Indexed: 11/10/2022] Open
Abstract
Tafenoquine (TQ) is an 8-aminoquinoline anti-malarial being developed for malaria prophylaxis. It has been generally assumed that TQ, administered prophylactically, acts primarily on the developing exoerythrocytic stages of malaria parasites (causal prophylaxis), and that polymorphisms in metabolic enzymes thought to impact the activity of other 8-aminoquinolines also inhibit this property of TQ. Furthermore, it has been suggested that a diagnostic test for CYP2D6 metabolizer status might be required. In field studies in which metabolic status was not an exclusion criteria, TQ has been shown to exhibit similar prophylactic efficacy as blood schizonticidal drugs (mefloquine). Also, its blood schizonticidal and anti-relapse efficacy is independent of 2D6 metabolizer status. The most reasonable explanation for the field study results, supported by other clinical and non-clinical data, is that TQ is not completely causal and exhibits substantial blood schizonticidal activity at the intended dose. Pharmacokinetic simulations demonstrate that trough concentrations of TQ exceed the proposed MIC of 80 ng/ml in >95% of individuals. Based on these data a companion diagnostic for CP450 enzyme status is not required.
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Affiliation(s)
- Geoffrey Dow
- 60 Degrees Pharmaceuticals LLC, 1025 Connecticut Ave NW Suite 1000, Washington, DC, 20036, USA.
| | - Bryan Smith
- 60 Degrees Pharmaceuticals LLC, 1025 Connecticut Ave NW Suite 1000, Washington, DC, 20036, USA
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9
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[Role of primaquine in malaria control and elimination in French-speaking Africa]. BULLETIN DE LA SOCIETE DE PATHOLOGIE EXOTIQUE (1990) 2017; 110:198-206. [PMID: 28417346 DOI: 10.1007/s13149-017-0556-z] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/07/2015] [Accepted: 12/05/2016] [Indexed: 12/20/2022]
Abstract
Primaquine, an 8-aminoquinoline, is a relatively unknown and underutilized drug in French-speaking African countries. It acts against the liver stage parasites of all human malaria species, asexual blood stages of Plasmodium vivax and, to a lesser degree, Plasmodium falciparum; P. falciparum mature gametocytes, and P. vivax and Plasmodium ovale hypnozoites. Gastrointestinal disturbances are its most common side effects. The clinical utility of primaquine is limited due to its hematological side effects in individuals with glucose-6-phosphate dehydrogenase (G6PD) deficiency and other contraindications (pregnant woman, breastfeeding woman, infants less than 6 months old). In the light of the recent recommendations of the World Health Organization (WHO), we propose to examine how primaquine can be used in French-speaking Africa to improve malaria control and move towards malaria elimination. Two indications supported by the WHO are of relevance in Africa. First, artemisinin-based combination therapies and primaquine given as a single low dose (0.25 mg base/kg) are effective to kill asexual and sexual parasites of P. falciparum, are well-tolerated, and have very little risk even in mild to moderate G6PD-deficient patients. This strategy may be helpful to contain transmission in an area in Africa where P. falciparum malaria incidence has decreased considerably. There is an ethical concern in administering primaquine as a gametocytocide as it does not confer any direct benefit to the treated patient. However, the single low-dose primaquine is most likely associated with very low risk for adverse hematological effects, and WHO recommends its use even without prior G6PD testing. In our opinion, clinical studies including G6PD test should be conducted to assess the safety of low-dose primaquine in African patients. Second, primaquine is effective and necessary for radical treatment of P. vivax and P. ovale, but the standard 14-day treatment (0.25-0.5 mg base/kg/day) is not recommended in patients with G6PD deficiency. Prior G6PD testing is required before prescribing primaquine for radical treatment. The use of primaquine for radical treatment in patients without contraindications does not raise any major ethical problem since the probability of relapse in patients who do not receive anti-hypnozoite treatment can be relatively high and each relapse can cause or aggravate anemia, especially in children. In our opinion, patients with mild or moderate G6PD deficiency should not be treated with primaquine at present. Further clinical studies are necessary to define the role of this drug for radical treatment in G6PD-deficient African patients. Without primaquine, the eventual elimination of P. vivax and P. ovale malaria appears to be very difficult. Updated epidemiological data on G6PD, Duffy antigen, and the current distribution of and burden due to P. vivax and P. ovale are required for a rational use of primaquine in the African continent. Moreover, clinical studies on primaquine are required in Africa.
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10
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Ebstie YA, Abay SM, Tadesse WT, Ejigu DA. Tafenoquine and its potential in the treatment and relapse prevention of Plasmodium vivax malaria: the evidence to date. Drug Des Devel Ther 2016; 10:2387-99. [PMID: 27528800 PMCID: PMC4970641 DOI: 10.2147/dddt.s61443] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
Despite declining global malaria incidence, the disease continues to be a threat to people living in endemic regions. In 2015, an estimated 214 million new malaria cases and 438,000 deaths due to malaria were recorded. Plasmodium vivax is the second most common cause of malaria next to Plasmodium falciparum. Vivax malaria is prevalent especially in Southeast Asia and the Horn of Africa, with enormous challenges in controlling the disease. Some of the challenges faced by vivax malaria-endemic countries include limited access to effective drugs treating liver stages of the parasite (schizonts and hypnozoites), emergence/spread of drug resistance, and misperception of vivax malaria as nonlethal. Primaquine, the only 8-aminoquinoline derivative approved by the US Food and Drug Administration, is intended to clear intrahepatic hypnozoites of P. vivax (radical cure). However, poor adherence to a prolonged treatment course, drug-induced hemolysis in patients with glucose-6-phosphate dehydrogenase deficiency, and the emergence of resistance make it imperative to look for alternative drugs. Therefore, this review focuses on data accrued to date on tafenoquine and gives insight on the potential role of the drug in preventing relapse and radical cure of patients with vivax malaria.
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Affiliation(s)
| | | | - Wondmagegn T Tadesse
- Department of Pharmacology and Clinical Pharmacy, School of Medicine, College of Health Sciences, Addis Ababa University
| | - Dawit A Ejigu
- Department of Pharmacology, St Paul’s Hospital Millennium Medical College, Addis Ababa, Ethiopia
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11
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Melariri P, Kalombo L, Nkuna P, Dube A, Hayeshi R, Ogutu B, Gibhard L, deKock C, Smith P, Wiesner L, Swai H. Oral lipid-based nanoformulation of tafenoquine enhanced bioavailability and blood stage antimalarial efficacy and led to a reduction in human red blood cell loss in mice. Int J Nanomedicine 2015; 10:1493-503. [PMID: 25759576 PMCID: PMC4346002 DOI: 10.2147/ijn.s76317] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
Tafenoquine (TQ), a new synthetic analog of primaquine, has relatively poor bioavailability and associated toxicity in glucose-6-phosphate dehydrogenase (G6PD)-deficient individuals. A microemulsion formulation of TQ (MTQ) with sizes <20 nm improved the solubility of TQ and enhanced the oral bioavailability from 55% to 99% in healthy mice (area under the curve 0 to infinity: 11,368±1,232 and 23,842±872 min·μmol/L) for reference TQ and MTQ, respectively. Average parasitemia in Plasmodium berghei-infected mice was four- to tenfold lower in the MTQ-treated group. In vitro antiplasmodial activities against chloroquine-sensitive and chloroquine-resistant strains of Plasmodium falciparum indicated no change in half maximal inhibitory concentration, suggesting that the microemulsion did not affect the inherent activity of TQ. In a humanized mouse model of G6PD deficiency, we observed reduction in toxicity of TQ as delivered by MTQ at low but efficacious concentrations of TQ. We hereby report an enhancement in the solubility, bioavailibility, and efficacy of TQ against blood stages of Plasmodium parasites without a corresponding increase in toxicity.
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Affiliation(s)
- Paula Melariri
- Polymers and Composites, Material Science and Manufacturing, Council for Scientific and Industrial Research, Port Elizabeth, South Africa
| | - Lonji Kalombo
- Polymer and Composites, Material Science and Manufacturing, Council for Scientific and Industrial Research, Pretoria, South Africa
| | - Patric Nkuna
- Polymer and Composites, Material Science and Manufacturing, Council for Scientific and Industrial Research, Pretoria, South Africa
| | - Admire Dube
- Polymer and Composites, Material Science and Manufacturing, Council for Scientific and Industrial Research, Pretoria, South Africa ; School of Pharmacy, University of the Western Cape, Bellville, South Africa
| | - Rose Hayeshi
- Polymer and Composites, Material Science and Manufacturing, Council for Scientific and Industrial Research, Pretoria, South Africa
| | - Benhards Ogutu
- Centre for Research in Therapeutic Sciences, Strathmore University, Nairobi, Kenya ; Centre for Clinical Research, Kenya Medical Research Institute, Nairobi, Kenya
| | - Liezl Gibhard
- Division of Pharmacology, University of Cape Town Medical School, Groote Schuur Hospital, Cape Town, South Africa
| | - Carmen deKock
- Division of Pharmacology, University of Cape Town Medical School, Groote Schuur Hospital, Cape Town, South Africa
| | - Peter Smith
- Division of Pharmacology, University of Cape Town Medical School, Groote Schuur Hospital, Cape Town, South Africa
| | - Lubbe Wiesner
- Division of Pharmacology, University of Cape Town Medical School, Groote Schuur Hospital, Cape Town, South Africa
| | - Hulda Swai
- Polymer and Composites, Material Science and Manufacturing, Council for Scientific and Industrial Research, Pretoria, South Africa
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Fall B, Camara C, Fall M, Nakoulima A, Dionne P, Diatta B, Diemé Y, Wade B, Pradines B. Plasmodium falciparum susceptibility to standard and potential anti-malarial drugs in Dakar, Senegal, during the 2013-2014 malaria season. Malar J 2015; 14:60. [PMID: 25849097 PMCID: PMC4334420 DOI: 10.1186/s12936-015-0589-3] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2014] [Accepted: 01/27/2015] [Indexed: 11/28/2022] Open
Abstract
Background In 2006, the Senegalese National Malaria Control Programme recommended artemisinin-based combination therapy (ACT) as the first-line treatment for uncomplicated malaria. Since the introduction of ACT, there have been very few reports on the level of Plasmodium falciparum resistance to anti-malarial drugs. An ex vivo susceptibility study was conducted on local isolates obtained from the Hôpital Principal de Dakar (Dakar, Senegal) from November 2013 to January 2014. Methods Eighteen P. falciparum isolates were sussessfully assessed for ex vivo susceptibility to chloroquine (CQ), quinine (QN), monodesethylamodiaquine (MDAQ), the active metabolite of amodiaquine, mefloquine (MQ), lumefantrine (LMF), artesunate (AS), dihydroartemisinin (DHA), the active metabolite of artemisinin derivatives, pyronaridine (PND), piperaquine (PPQ), and, Proveblue (PVB), a methylene blue preparation, using the HRP2-based ELISA test. Results The prevalence of isolates with reduced susceptibility was 55.6% for MQ, 50% for CQ, 5.6% for QN and MDAQ, and 0% for DHA, AS and LMF. The mean IC50 for PND, PPQ and PVB were 5.8 nM, 32.2 nM and 5.3 nM, respectively. Conclusions The prevalence of isolates with a reduced susceptibility to MQ remains high and stable in Dakar. Since 2004, the prevalence of CQ resistance decreased, but rebounded in 2013 in Dakar. PND, PPQ and PVB showed high in vitro activity in P. falciparum parasites from Dakar.
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Miller AK, Harrell E, Ye L, Baptiste-Brown S, Kleim JP, Ohrt C, Duparc S, Möhrle JJ, Webster A, Stinnett S, Hughes A, Griffith S, Beelen AP. Pharmacokinetic interactions and safety evaluations of coadministered tafenoquine and chloroquine in healthy subjects. Br J Clin Pharmacol 2014; 76:858-67. [PMID: 23701202 DOI: 10.1111/bcp.12160] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2012] [Accepted: 05/09/2013] [Indexed: 11/28/2022] Open
Abstract
AIMS The long-acting 8-aminoquinoline tafenoquine (TQ) coadministered with chloroquine (CQ) may radically cure Plasmodium vivax malaria. Coadministration therapy was evaluated for a pharmacokinetic interaction and for pharmacodynamic, safety and tolerability characteristics. METHODS Healthy subjects, 18-55 years old, without documented glucose-6-phosphate dehydrogenase deficiency, received CQ alone (days 1-2, 600 mg; and day 3, 300 mg), TQ alone (days 2 and 3, 450 mg) or coadministration therapy (day 1, CQ 600 mg; day 2, CQ 600 mg + TQ 450 mg; and day 3, CQ 300 mg + TQ 450 mg) in a randomized, double-blind, parallel-group study. Blood samples for pharmacokinetic and pharmacodynamic analyses and safety data, including electrocardiograms, were collected for 56 days. RESULTS The coadministration of CQ + TQ had no effect on TQ AUC0-t , AUC0-∞ , Tmax or t1/2 . The 90% confidence intervals of CQ + TQ vs. TQ for AUC0-t , AUC0-∞ and t1/2 indicated no drug interaction. On day 2 of CQ + TQ coadministration, TQ Cmax and AUC0-24 increased by 38% (90% confidence interval 1.27, 1.64) and 24% (90% confidence interval 1.04, 1.46), respectively. The pharmacokinetics of CQ and its primary metabolite desethylchloroquine were not affected by TQ. Coadministration had no clinically significant effect on QT intervals and was well tolerated. CONCLUSIONS No clinically significant safety or pharmacokinetic/pharmacodynamic interactions were observed with coadministered CQ and TQ in healthy subjects.
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Migliani R, Pradines B, Michel R, Aoun O, Dia A, Deparis X, Rapp C. Malaria control strategies in French armed forces. Travel Med Infect Dis 2014; 12:307-17. [PMID: 25069406 DOI: 10.1016/j.tmaid.2014.05.008] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/26/2013] [Revised: 05/11/2014] [Accepted: 05/13/2014] [Indexed: 10/25/2022]
Abstract
Each year, 40,000 French soldiers deploy or travel through malaria-endemic areas. Despite the effective control measures that were successively implemented, malaria remains a public health concern in French armed forces with several important outbreaks and one lethal case every two years. This article describes the malaria control strategy in French armed forces which is based on three combined strategies: i) Anopheles vector control to prevent infection with the implementation of personal protection against vectors (PPAV) adapted to the field living conditions of the troops. ii) Chemoprophylaxis (CP) to prevent the disease based on prescription of effective and well tolerated doxycycline. iii) Management of cases through early diagnosis and appropriate treatment to prevent death. In isolated conditions in endemic areas, rapid diagnosis tests (RDT) are used as first-line tests by military doctors. Treatment of uncomplicated Plasmodium falciparum (P. falciparum) malaria is based either on the piperaquine tetraphosphate-dihydroartemisinin association since 2013, or on the atovaquone-proguanil association. First-line treatment of severe P. falciparum malaria is based on IV artesunate. These measures are associated with constant education of the military, epidemiological surveillance of malaria cases and monitoring of parasite chemosensitivity.
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Affiliation(s)
| | - B Pradines
- Institut de recherche biomédicale des armées, Brétigny-sur-Orge, France; Aix Marseille Université, Unité de Recherche sur les Maladies Infectieuses et Tropicales Emergentes, UM 63, CNRS 7278, IRD 198, Inserm 1095, Marseille, France
| | - R Michel
- Centre d'épidémiologie et de santé publique des armées, Marseille, France
| | - O Aoun
- Service des maladies infectieuses et tropicales, Hôpital d'instruction des armées Bégin, Saint-Mandé, France
| | - A Dia
- Centre d'épidémiologie et de santé publique des armées, Marseille, France
| | - X Deparis
- Ecole du Val de Grâce, Paris, France; Centre d'épidémiologie et de santé publique des armées, Marseille, France
| | - C Rapp
- Ecole du Val de Grâce, Paris, France; Service des maladies infectieuses et tropicales, Hôpital d'instruction des armées Bégin, Saint-Mandé, France
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15
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Green JA, Patel AK, Patel BR, Hussaini A, Harrell EJ, McDonald MJ, Carter N, Mohamed K, Duparc S, Miller AK. Tafenoquine at therapeutic concentrations does not prolong Fridericia-corrected QT interval in healthy subjects. J Clin Pharmacol 2014; 54:995-1005. [PMID: 24700490 PMCID: PMC4283056 DOI: 10.1002/jcph.302] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2014] [Accepted: 04/01/2014] [Indexed: 11/10/2022]
Abstract
Tafenoquine is being developed for relapse prevention in Plasmodium vivax malaria. This Phase I, single-blind, randomized, placebo- and active-controlled parallel group study investigated whether tafenoquine at supratherapeutic and therapeutic concentrations prolonged cardiac repolarization in healthy volunteers. Subjects aged 18-65 years were randomized to one of five treatment groups (n = 52 per group) to receive placebo, tafenoquine 300, 600, or 1200 mg, or moxifloxacin 400 mg (positive control). Lack of effect was demonstrated if the upper 90% CI of the change from baseline in QTcF following supratherapeutic tafenoquine 1200 mg versus placebo (ΔΔQTcF) was <10 milliseconds for all pre-defined time points. The maximum ΔΔQTcF with tafenoquine 1200 mg (n = 50) was 6.39 milliseconds (90% CI 2.85, 9.94) at 72 hours post-final dose; that is, lack of effect for prolongation of cardiac depolarization was demonstrated. Tafenoquine 300 mg (n = 48) or 600 mg (n = 52) had no effect on ΔΔQTcF. Pharmacokinetic/pharmacodynamic modeling of the tafenoquine-QTcF concentration-effect relationship demonstrated a shallow slope (0.5 ms/μg mL(-1) ) over a wide concentration range. For moxifloxacin (n = 51), maximum ΔΔQTcF was 8.52 milliseconds (90% CI 5.00, 12.04), demonstrating assay sensitivity. In this thorough QT/QTc study, tafenoquine did not have a clinically meaningful effect on cardiac repolarization.
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Affiliation(s)
- Justin A Green
- Diseases of the Developing World Group, GlaxoSmithKline Research and Development, Stockley Park West, Uxbridge, Middlesex, UK
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16
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Marcsisin SR, Sousa JC, Reichard GA, Caridha D, Zeng Q, Roncal N, McNulty R, Careagabarja J, Sciotti RJ, Bennett JW, Zottig VE, Deye G, Li Q, Read L, Hickman M, Dhammika Nanayakkara NP, Walker LA, Smith B, Melendez V, Pybus BS. Tafenoquine and NPC-1161B require CYP 2D metabolism for anti-malarial activity: implications for the 8-aminoquinoline class of anti-malarial compounds. Malar J 2014; 13:2. [PMID: 24386891 PMCID: PMC3893421 DOI: 10.1186/1475-2875-13-2] [Citation(s) in RCA: 60] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2013] [Accepted: 12/22/2013] [Indexed: 12/03/2022] Open
Abstract
Background Tafenoquine (TQ) is an 8-aminoquinoline (8AQ) that has been tested in several Phase II and Phase III clinical studies and is currently in late stage development as an anti-malarial prophylactic agent. NPC-1161B is a promising 8AQ in late preclinical development. It has recently been reported that the 8AQ drug primaquine requires metabolic activation by CYP 2D6 for efficacy in humans and in mice, highlighting the importance of pharmacogenomics in the target population when administering primaquine. A logical follow-up study was to determine whether CYP 2D activation is required for other compounds in the 8AQ structural class. Methods In the present study, the anti-malarial activities of NPC-1161B and TQ were assessed against luciferase expressing Plasmodium berghei in CYP 2D knock-out mice in comparison with normal C57BL/6 mice (WT) and with humanized/CYP 2D6 knock-in mice by monitoring luminescence with an in vivo imaging system. These experiments were designed to determine the direct effects of CYP 2D metabolic activation on the anti-malarial efficacy of NPC-1161B and TQ. Results NPC-1161B and TQ exhibited no anti-malarial activity in CYP 2D knock-out mice when dosed at their ED100 values (1 mg/kg and 3 mg/kg, respectively) established in WT mice. TQ anti-malarial activity was partially restored in humanized/CYP 2D6 knock-in mice when tested at two times its ED100. Conclusions The results reported here strongly suggest that metabolism of NPC-1161B and TQ by the CYP 2D enzyme class is essential for their anti-malarial activity. Furthermore, these results may provide a possible explanation for therapeutic failures for patients who do not respond to 8AQ treatment for relapsing malaria. Because CYP 2D6 is highly polymorphic, variable expression of this enzyme in humans represents a significant pharmacogenomic liability for 8AQs which require CYP 2D metabolic activation for efficacy, particularly for large-scale prophylaxis and eradication campaigns.
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Affiliation(s)
- Sean R Marcsisin
- Division of Experimental Therapeutics, Military Malaria Research Program, Walter Reed Army Institute of Research, 503 Robert Grant Ave, Silver Spring, MD 20910, USA.
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Quashie NB, Duah NO, Abuaku B, Quaye L, Ayanful-Torgby R, Akwoviah GA, Kweku M, Johnson JD, Lucchi NW, Udhayakumar V, Duplessis C, Kronmann KC, Koram KA. A SYBR Green 1-based in vitro test of susceptibility of Ghanaian Plasmodium falciparum clinical isolates to a panel of anti-malarial drugs. Malar J 2013; 12:450. [PMID: 24341604 PMCID: PMC3878558 DOI: 10.1186/1475-2875-12-450] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2013] [Accepted: 12/10/2013] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Based on report of declining efficacy of chloroquine, Ghana shifted to the use of artemisinin-based combination therapy (ACT) in 2005 as the first-line anti-malarial drug. Since then, there has not been any major evaluation of the efficacy of anti-malarial drugs in Ghana in vitro. The sensitivity of Ghanaian Plasmodium falciparum isolates to anti-malarial drugs was, therefore, assessed and the data compared with that obtained prior to the change in the malaria treatment policy. METHODS A SYBR Green 1 fluorescent-based in vitro drug sensitivity assay was used to assess the susceptibility of clinical isolates of P. falciparum to a panel of 12 anti-malarial drugs in three distinct eco-epidemiological zones in Ghana. The isolates were obtained from children visiting health facilities in sentinel sites located in Hohoe, Navrongo and Cape Coast municipalities. The concentration of anti-malarial drug inhibiting parasite growth by 50% (IC50) for each drug was estimated using the online program, ICEstimator. RESULTS Pooled results from all the sentinel sites indicated geometric mean IC50 values of 1.60, 3.80, 4.00, 4.56, 5.20, 6.11, 10.12, 28.32, 31.56, 93.60, 107.20, and 8952.50 nM for atovaquone, artesunate, dihydroartemisin, artemether, lumefantrine, amodiaquine, mefloquine, piperaquine, chloroquine, tafenoquine, quinine, and doxycycline, respectively. With reference to the literature threshold value indicative of resistance, the parasites showed resistance to all the test drugs except the artemisinin derivatives, atovaquone and to a lesser extent, lumefantrine. There was nearly a two-fold decrease in the IC50 value determined for chloroquine in this study compared to that determined in 2004 (57.56 nM). This observation is important, since it suggests a significant improvement in the efficacy of chloroquine, probably as a direct consequence of reduced drug pressure after cessation of its use. Compared to that measured prior to the change in treatment policy, significant elevation of artesunate IC50 value was observed. The results also suggest the existence of possible cross-resistance among some of the test drugs. CONCLUSION Ghanaian P. falciparum isolates, to some extent, have become susceptible to chloroquine in vitro, however the increasing trend in artesunate IC50 value observed should be of concern. Continuous monitoring of ACT in Ghana is recommended.
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Affiliation(s)
- Neils B Quashie
- Centre for Tropical Clinical Pharmacology and Therapeutics, University of Ghana Medical School, Accra, Ghana.
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18
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Gorka AP, Jacobs LM, Roepe PD. Cytostatic versus cytocidal profiling of quinoline drug combinations via modified fixed-ratio isobologram analysis. Malar J 2013; 12:332. [PMID: 24044530 PMCID: PMC3874740 DOI: 10.1186/1475-2875-12-332] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2013] [Accepted: 08/18/2013] [Indexed: 01/13/2023] Open
Abstract
Background Drug combination therapy is the frontline of malaria treatment. There is an ever-accelerating need for new, efficacious combination therapies active against drug resistant malaria. Proven drugs already in the treatment pipeline, such as the quinolines, are important components of current combination therapy and also present an attractive test bank for rapid development of new concepts. Methods The efficacy of several drug combinations versus chloroquine-sensitive and chloroquine-resistant strains was measured using both cytostatic and cytocidal potency assays. Conclusions These screens identify quinoline and non-quinoline pairs that exhibit synergy, additivity, or antagonism using the fixed-ratio isobologram method and find tafenoquine – methylene blue combination to be the most synergistic. Also, interestingly, for selected pairs, additivity, synergy, or antagonism defined by quantifying IC50 (cytostatic potency) does not necessarily predict similar behaviour when potency is defined by LD50 (cytocidal potency). These data further support an evolving new model for quinoline anti-malarials, wherein haem and haemozoin are the principle target for cytostatic activity, but may not be the only target relevant for cytocidal activity.
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Affiliation(s)
- Alexander P Gorka
- Department of Chemistry, Department of Biochemistry, Cellular, & Molecular Biology, and Center for Infectious Disease, Georgetown University, 37th and 'O' Sts, NW, Washington, DC, 20057, USA.
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Abstract
Drugs that kill or inhibit the sexual stages of Plasmodium in order to prevent transmission are important components of malaria control programmes. Reducing gametocyte carriage is central to the control of Plasmodium falciparum transmission as infection can result in extended periods of gametocytaemia. Unfortunately the number of drugs with activity against gametocytes is limited. Primaquine is currently the only licensed drug with activity against the sexual stages of malaria parasites and its use is hampered by safety concerns. This shortcoming is likely the result of the technical challenges associated with gametocyte studies together with the focus of previous drug discovery campaigns on asexual parasite stages. However recent emphasis on malaria eradication has resulted in an upsurge of interest in identifying compounds with activity against gametocytes. This review examines the gametocytocidal properties of currently available drugs as well as those in the development pipeline and examines the prospects for discovery of new anti-gametocyte compounds.
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Fall B, Pascual A, Sarr FD, Wurtz N, Richard V, Baret E, Diémé Y, Briolant S, Bercion R, Wade B, Tall A, Pradines B. Plasmodium falciparum susceptibility to anti-malarial drugs in Dakar, Senegal, in 2010: an ex vivo and drug resistance molecular markers study. Malar J 2013; 12:107. [PMID: 23510258 PMCID: PMC3606842 DOI: 10.1186/1475-2875-12-107] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2012] [Accepted: 03/10/2013] [Indexed: 11/18/2022] Open
Abstract
Background In 2006, the Senegalese National Malaria Control Programme recommended artemisinin-based combination therapy (ACT) as the first-line treatment for uncomplicated malaria. Since the introduction of ACT, there have been very few reports on the level of resistance of P. falciparum to anti-malarial drugs. To determine whether parasite susceptibility has been affected by the new anti-malarial policies, an ex vivo susceptibility and drug resistance molecular marker study was conducted on local isolates obtained from the Centre de santé Elizabeth Diouf (Médina, Dakar, Senegal). Methods The prevalence of genetic polymorphisms in genes associated with anti-malarial drug resistance, i.e., pfcrt, pfdhfr, pfdhps and pfmdr1, were evaluated for a panel of 165 isolates collected from patients recruited from 17 August 2010 to 6 January 2011. The malaria isolates were assessed for susceptibility to chloroquine (CQ); quinine (QN); monodesethylamodiaquine (MDAQ), the active metabolite of amodiaquine; mefloquine (MQ); lumefantrine (LMF); dihydroartemisinin (DHA), the active metabolite of artemisinin derivatives; and doxycycline (DOX) using the Plasmodium lactate dehydrogenase (pLDH) ELISA. Results The prevalence of the in vitro resistant isolates, or isolates with reduced susceptibility, was 62.1% for MQ, 24.2% for CQ, 10.3% for DOX, 11.8% MDAQ, 9.7% for QN, 2.9% for LMF and 0% for DHA. The Pfcrt 76T mutation was identified in 43.6% of the samples. The pfmdr1 86Y, 184F and 1246Y mutations were found in 16.2%, 50.0% and 1.6% of the samples, respectively. The pfdhfr 108N, 51I and 59R mutations were identified in 81.9%, 77.4% and 79.4% of the samples, respectively. The double mutant (108N and 51I) was detected in 75.5% of the isolates, and the triple mutant (108N, 51I and 59R) was detected in 73.6% of the isolates. The pfdhps 437G, 436A and 613S mutations were found in 54.4%, 38.6% and 1.2% of the samples, respectively. There was only one double mutant, 437G and 540E, and one quintuple mutant, pfdhfr 108N, 51I and 59R and pfdhps 437G and 540E. The prevalence of the quadruple mutant (pfdhfr 108N, 51I and 59R and pfdhps 437G) was 36.7%. Conclusions The results of this study indicate that an intensive surveillance of the in vitro P. falciparum susceptibility to anti-malarial drugs must be conducted in Senegal.
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Affiliation(s)
- Bécaye Fall
- Laboratoire d'étude de la chimiosensibilité du paludisme, Fédération des laboratoires, Hôpital Principal de Dakar, Dakar, Sénégal
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Dechy-Cabaret O, Benoit-Vical F. Effects of Antimalarial Molecules on the Gametocyte Stage of Plasmodium falciparum: The Debate. J Med Chem 2012; 55:10328-44. [DOI: 10.1021/jm3005898] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Affiliation(s)
- Odile Dechy-Cabaret
- CNRS, LCC (Laboratoire de Chimie de Coordination), 205 Route de Narbonne, BP
44099, F-31077 Toulouse Cedex 4, France
- Université de Toulouse, UPS, INPT, F-31077 Toulouse Cedex 4, France
| | - Françoise Benoit-Vical
- CNRS, LCC (Laboratoire de Chimie de Coordination), 205 Route de Narbonne, BP
44099, F-31077 Toulouse Cedex 4, France
- Université de Toulouse, UPS, INPT, F-31077 Toulouse Cedex 4, France
- Service de Parasitologie-Mycologie
and Faculté de Médecine de Rangueil, Centre Hospitalier Universitaire de Toulouse, Toulouse, France
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Wurtz N, Fall B, Pascual A, Diawara S, Sow K, Baret E, Diatta B, Fall KB, Mbaye PS, Fall F, Diémé Y, Rogier C, Bercion R, Briolant S, Wade B, Pradines B. Prevalence of molecular markers of Plasmodium falciparum drug resistance in Dakar, Senegal. Malar J 2012; 11:197. [PMID: 22694921 PMCID: PMC3470961 DOI: 10.1186/1475-2875-11-197] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2012] [Accepted: 06/02/2012] [Indexed: 12/03/2022] Open
Abstract
Background As a result of the widespread resistance to chloroquine and sulphadoxine-pyrimethamine, artemisinin-based combination therapy (ACT) (including artemether-lumefantrine and artesunate-amodiaquine) has been recommended as a first-line anti-malarial regimen in Senegal since 2006. Intermittent preventive treatments with anti-malarial drugs based on sulphadoxine-pyrimethamine are also given to children or pregnant women once per month during the transmission season. Since 2006, there have been very few reports on the susceptibility of Plasmodium falciparum to anti-malarial drugs. To estimate the prevalence of resistance to several anti-malarial drugs since the introduction of the widespread use of ACT, the presence of molecular markers associated with resistance to chloroquine and sulphadoxine-pyrimethamine was assessed in local isolates at the military hospital of Dakar. Methods The prevalence of genetic polymorphisms in genes associated with anti-malarial drug resistance, i.e., Pfcrt, Pfdhfr, Pfdhps and Pfmdr1, and the copy number of Pfmdr1 were evaluated for a panel of 174 isolates collected from patients recruited at the military hospital of Dakar from 14 October 2009 to 19 January 2010. Results The Pfcrt 76T mutation was identified in 37.2% of the samples. The Pfmdr1 86Y and 184F mutations were found in 16.6% and 67.6% of the tested samples, respectively. Twenty-eight of the 29 isolates with the 86Y mutation were also mutated at codon 184. Only one isolate (0.6%) had two copies of Pfmdr1. The Pfdhfr 108N/T, 51I and 59R mutations were identified in 82.4%, 83.5% and 74.1% of the samples, respectively. The double mutant (108N and 51I) was detected in 83.5% of the isolates, and the triple mutant (108N, 51I and 59R) was detected in 75.3%. The Pfdhps 437G, 436F/A and 613S mutations were found in 40.2%, 35.1% and 1.8% of the samples, respectively. There was no double mutant (437G and 540E) or no quintuple mutant (Pfdhfr 108N, 51I and 59R and Pfdhps 437G and 540E). The prevalence of the quadruple mutant (Pfdhfr 108N, 51I and 59R and Pfdhps 437G) was 36.5%. Conclusions Since 2004, the prevalence of chloroquine resistance had decreased. The prevalence of isolates with high-level pyrimethamine resistance is 83.5%. The prevalence of isolates resistant to sulphadoxine is 40.2%. However, no quintuple mutant (Pfdhfr 108N, 51I and 59R and Pfdhps 437G and 540E), which is associated with a high level of sulphadoxine-pyrimethamine resistance, has been identified to date. The resistance to amodiaquine remains moderate.
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Affiliation(s)
- Nathalie Wurtz
- Unité de parasitologie, UMR 6236, Institut de recherche biomédicale des armées, Marseille, France
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Antimalarial activity of the anticancer histone deacetylase inhibitor SB939. Antimicrob Agents Chemother 2012; 56:3849-56. [PMID: 22508312 DOI: 10.1128/aac.00030-12] [Citation(s) in RCA: 59] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Histone deacetylase (HDAC) enzymes posttranslationally modify lysines on histone and nonhistone proteins and play crucial roles in epigenetic regulation and other important cellular processes. HDAC inhibitors (e.g., suberoylanilide hydroxamic acid [SAHA; also known as vorinostat]) are used clinically to treat some cancers and are under investigation for use against many other diseases. Development of new HDAC inhibitors for noncancer indications has the potential to be accelerated by piggybacking onto cancer studies, as several HDAC inhibitors have undergone or are undergoing clinical trials. One such compound, SB939, is a new orally active hydroxamate-based HDAC inhibitor with an improved pharmacokinetic profile compared to that of SAHA. In this study, the in vitro and in vivo antiplasmodial activities of SB939 were investigated. SB939 was found to be a potent inhibitor of the growth of Plasmodium falciparum asexual-stage parasites in vitro (50% inhibitory concentration [IC(50)], 100 to 200 nM), causing hyperacetylation of parasite histone and nonhistone proteins. In combination with the aspartic protease inhibitor lopinavir, SB939 displayed additive activity. SB939 also potently inhibited the in vitro growth of exoerythrocytic-stage Plasmodium parasites in liver cells (IC(50), ~150 nM), suggesting that inhibitor targeting to multiple malaria parasite life cycle stages may be possible. In an experimental in vivo murine model of cerebral malaria, orally administered SB939 significantly inhibited P. berghei ANKA parasite growth, preventing development of cerebral malaria-like symptoms. These results identify SB939 as a potent new antimalarial HDAC inhibitor and underscore the potential of investigating next-generation anticancer HDAC inhibitors as prospective new drug leads for treatment of malaria.
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Meister S, Plouffe DM, Kuhen KL, Bonamy GMC, Wu T, Barnes SW, Bopp SE, Borboa R, Bright AT, Che J, Cohen S, Dharia NV, Gagaring K, Gettayacamin M, Gordon P, Groessl T, Kato N, Lee MCS, McNamara CW, Fidock DA, Nagle A, Nam TG, Richmond W, Roland J, Rottmann M, Zhou B, Froissard P, Glynne RJ, Mazier D, Sattabongkot J, Schultz PG, Tuntland T, Walker JR, Zhou Y, Chatterjee A, Diagana TT, Winzeler EA. Imaging of Plasmodium liver stages to drive next-generation antimalarial drug discovery. Science 2011; 334:1372-7. [PMID: 22096101 PMCID: PMC3473092 DOI: 10.1126/science.1211936] [Citation(s) in RCA: 252] [Impact Index Per Article: 19.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
Abstract
Most malaria drug development focuses on parasite stages detected in red blood cells, even though, to achieve eradication, next-generation drugs active against both erythrocytic and exo-erythrocytic forms would be preferable. We applied a multifactorial approach to a set of >4000 commercially available compounds with previously demonstrated blood-stage activity (median inhibitory concentration < 1 micromolar) and identified chemical scaffolds with potent activity against both forms. From this screen, we identified an imidazolopiperazine scaffold series that was highly enriched among compounds active against Plasmodium liver stages. The orally bioavailable lead imidazolopiperazine confers complete causal prophylactic protection (15 milligrams/kilogram) in rodent models of malaria and shows potent in vivo blood-stage therapeutic activity. The open-source chemical tools resulting from our effort provide starting points for future drug discovery programs, as well as opportunities for researchers to investigate the biology of exo-erythrocytic forms.
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Affiliation(s)
- Stephan Meister
- Department of Genetics, The Scripps Research Institute, La Jolla, CA 92037, USA
| | - David M Plouffe
- Genomics Institute of the Novartis Research Foundation, San Diego, CA 92121, USA
| | - Kelli L Kuhen
- Genomics Institute of the Novartis Research Foundation, San Diego, CA 92121, USA
| | - Ghislain MC Bonamy
- Genomics Institute of the Novartis Research Foundation, San Diego, CA 92121, USA
| | - Tao Wu
- Genomics Institute of the Novartis Research Foundation, San Diego, CA 92121, USA
| | - S Whitney Barnes
- Genomics Institute of the Novartis Research Foundation, San Diego, CA 92121, USA
| | - Selina E Bopp
- Department of Genetics, The Scripps Research Institute, La Jolla, CA 92037, USA
| | - Rachel Borboa
- Genomics Institute of the Novartis Research Foundation, San Diego, CA 92121, USA
| | - A Taylor Bright
- Department of Genetics, The Scripps Research Institute, La Jolla, CA 92037, USA
- Biomedical Sciences Graduate Program, UC San Diego, La Jolla, CA 92093, USA
| | - Jianwei Che
- Genomics Institute of the Novartis Research Foundation, San Diego, CA 92121, USA
| | - Steve Cohen
- Genomics Institute of the Novartis Research Foundation, San Diego, CA 92121, USA
| | - Neekesh V Dharia
- Department of Genetics, The Scripps Research Institute, La Jolla, CA 92037, USA
| | - Kerstin Gagaring
- Genomics Institute of the Novartis Research Foundation, San Diego, CA 92121, USA
| | | | - Perry Gordon
- Genomics Institute of the Novartis Research Foundation, San Diego, CA 92121, USA
| | - Todd Groessl
- Genomics Institute of the Novartis Research Foundation, San Diego, CA 92121, USA
| | - Nobutaka Kato
- Genomics Institute of the Novartis Research Foundation, San Diego, CA 92121, USA
| | - Marcus CS Lee
- Department of Microbiology & Immunology, Columbia University Medical Center, New York, NY 10032, USA
| | - Case W McNamara
- Genomics Institute of the Novartis Research Foundation, San Diego, CA 92121, USA
| | - David A Fidock
- Department of Microbiology & Immunology, Columbia University Medical Center, New York, NY 10032, USA
- Department of Medicine (Division of Infectious Diseases), Columbia University Medical Center, New York, NY 10032, USA
| | - Advait Nagle
- Genomics Institute of the Novartis Research Foundation, San Diego, CA 92121, USA
| | - Tae-gyu Nam
- Department of Chemistry, The Scripps Research Institute, La Jolla, CA 92037, USA
| | - Wendy Richmond
- Genomics Institute of the Novartis Research Foundation, San Diego, CA 92121, USA
| | - Jason Roland
- Genomics Institute of the Novartis Research Foundation, San Diego, CA 92121, USA
| | - Matthias Rottmann
- Swiss Tropical and Public Health Institute, Parasite Chemotherapy, CH-4002 Basel, Switzerland
- University of Basel, CH-4003 Basel, Switzerland
| | - Bin Zhou
- Genomics Institute of the Novartis Research Foundation, San Diego, CA 92121, USA
| | - Patrick Froissard
- INSERM, U945, Paris, France
- Université Pierre et Marie Curie-Paris, UMR S511 Paris, France
| | - Richard J Glynne
- Genomics Institute of the Novartis Research Foundation, San Diego, CA 92121, USA
| | - Dominique Mazier
- INSERM, U945, Paris, France
- Université Pierre et Marie Curie-Paris, UMR S511 Paris, France
- AP-HP, Groupe hospitalier Pitié-Salpêtrière, Service Parasitologie-Mycologie, Paris, France
| | | | - Peter G Schultz
- Department of Chemistry, The Scripps Research Institute, La Jolla, CA 92037, USA
| | - Tove Tuntland
- Genomics Institute of the Novartis Research Foundation, San Diego, CA 92121, USA
| | - John R Walker
- Genomics Institute of the Novartis Research Foundation, San Diego, CA 92121, USA
| | - Yingyao Zhou
- Genomics Institute of the Novartis Research Foundation, San Diego, CA 92121, USA
| | - Arnab Chatterjee
- Genomics Institute of the Novartis Research Foundation, San Diego, CA 92121, USA
| | | | - Elizabeth A Winzeler
- Department of Genetics, The Scripps Research Institute, La Jolla, CA 92037, USA
- Genomics Institute of the Novartis Research Foundation, San Diego, CA 92121, USA
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Ollivier L, Nevin RL, Darar HY, Bougère J, Saleh M, Gidenne S, Maslin J, Anders D, Decam C, Todesco A, Khaireh BA, Ahmed AA. Malaria in the Republic of Djibouti, 1998-2009. Am J Trop Med Hyg 2011; 85:554-9. [PMID: 21896822 DOI: 10.4269/ajtmh.2011.11-0122] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Abstract
Historically, native populations in the Republic of Djibouti have experienced only low and unstable malaria transmission and intermittent epidemics. In recent years, efforts at malaria control have been aggressively pursued. This study was performed to inform revised malaria prevention recommendations for military service members and international travelers to the country. Laboratory-confirmed cases of malaria documented at large medical facilities and within military and civilian health care systems in the Republic of Djibouti from 1998 to 2009 were reviewed. In recent years, fewer than 5% of febrile cases among the three largest passive surveillance systems were laboratory-confirmed as malaria, and incidence of confirmed malaria was well below 1/1,000 persons/year. As efforts in the Republic of Djibouti progress toward elimination, and in conjunction with continued efforts at surveillance, emphasizing mosquito-avoidance measures and standby emergency treatment will become reasonable recommendations for malaria prevention.
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Affiliation(s)
- Lénaïck Ollivier
- Direction Centrale du Service de Santé des Armées, Paris, France.
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Fall B, Diawara S, Sow K, Baret E, Diatta B, Fall KB, Mbaye PS, Fall F, Diémé Y, Rogier C, Wade B, Bercion R, Pradines B. Ex vivo susceptibility of Plasmodium falciparum isolates from Dakar, Senegal, to seven standard anti-malarial drugs. Malar J 2011; 10:310. [PMID: 22014157 PMCID: PMC3210113 DOI: 10.1186/1475-2875-10-310] [Citation(s) in RCA: 41] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2011] [Accepted: 10/20/2011] [Indexed: 11/15/2022] Open
Abstract
Background As a result of widespread chloroquine and sulphadoxine-pyrimethamine resistance, artemisinin-based combination therapy (ACT) (which includes artemether-lumefantrine and artesunate-amodiaquine) has been recommended as a first-line anti-malarial regimen in Senegal since 2006. Since then, there have been very few reports on the ex vivo susceptibility of Plasmodium falciparum to anti-malarial drugs. To examine whether parasite susceptibility has been affected by the widespread use of ACT, the ex vivo susceptibility of local isolates was assessed at the military hospital of Dakar. Methods The ex vivo susceptibility of 93 P. falciparum isolates from Dakar was successfully determined using the Plasmodium lactate dehydrogenase (pLDH) ELISA for the following drugs: chloroquine (CQ), quinine (QN), mefloquine (MQ), monodesethylamodiaquine (MDAQ), lumefantrine (LMF), dihydroartemisinin (DHA) and doxycycline (DOX). Results After transformation of the isolate IC50 in ratio of IC50 according to the susceptibility of the 3D7 reference strain (isolate IC50/3D7 IC50), the prevalence of the in vitro resistant isolates with reduced susceptibility was 50% for MQ, 22% for CQ, 12% for DOX, 6% for both QN and MDAQ and 1% for the drugs LMF and DHA. The highest significant positive correlations were shown between responses to CQ and MDAQ (r = 0.569; P < 0.0001), LMF and QN (r = 0.511; P < 0.0001), LMF and DHA (r = 0.428; P = 0.0001), LMF and MQ (r = 0.413; P = 0.0002), QN and DHA (r = 0.402; P = 0.0003) and QN and MQ (r = 0.421; P = 0.0001). Conclusions The introduction of ACT in 2002 has not induced a decrease in P. falciparum susceptibility to the drugs DHA, MDAQ and LMF, which are common ACT components. However, the prevalence of P. falciparum isolates with reduced susceptibility has increased for both MQ and DOX. Taken together, these data suggest that intensive surveillance of the P. falciparum in vitro susceptibility to anti-malarial drugs in Senegal is required.
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Affiliation(s)
- Bécaye Fall
- 1Laboratoire d’étude de la chimiosensibilité du paludisme, Fédération deslaboratoires, Hôpital Principal de Dakar, Dakar, Sénégal
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27
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Antiprotozoal compounds: state of the art and new developments. Int J Antimicrob Agents 2011; 38:118-24. [DOI: 10.1016/j.ijantimicag.2011.03.004] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2011] [Accepted: 03/08/2011] [Indexed: 11/20/2022]
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28
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Liu H, Walker LA, Dhammika Nanayakara NP, Doerksen RJ. Methemoglobinemia caused by 8-aminoquinoline drugs: DFT calculations suggest an analogy to H4B's role in nitric oxide synthase. J Am Chem Soc 2011; 133:1172-5. [PMID: 21244096 PMCID: PMC3070186 DOI: 10.1021/ja107472c] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
We suggest a possible mechanism of how 8-aminoquinolines (8-AQ's) cause hemotoxicity by oxidizing hemoglobin to methemoglobin. In our DFT calculations, we found that 5-hydroxyprimaquine is able to donate an electron to O(2) to facilitate its conversion to H(2)O(2). Meanwhile, Fe(II) is oxidized to Fe(III) and methemoglobin is formed. In this mechanism, the 8-AQ drug plays a similar role as that of H(4)B in nitric oxide synthase. Furthermore, our study offers an approach to inform the design of less toxic antimalarial drugs.
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Affiliation(s)
- Haining Liu
- Department of Medicinal Chemistry, University of Mississippi, University, MS 38677
| | - Larry A. Walker
- Department of Pharmacology, University of Mississippi, University, MS 38677
- National Center for Natural Products Research School of Pharmacy, University of Mississippi, University, MS 38677
| | - N. P. Dhammika Nanayakara
- National Center for Natural Products Research School of Pharmacy, University of Mississippi, University, MS 38677
| | - Robert J. Doerksen
- Department of Medicinal Chemistry, University of Mississippi, University, MS 38677
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29
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Schlitzer M. Antimalarial drugs - what is in use and what is in the pipeline. Arch Pharm (Weinheim) 2008; 341:149-63. [PMID: 18297679 DOI: 10.1002/ardp.200700184] [Citation(s) in RCA: 99] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Malaria continues to be a potentially fatal threat to almost half of the world's population. In light of this threat, the armory to fight this disease is rather limited. Resistance against the most common and affordable antimalarials is widespread. Only few new drugs are in clinical development, most of them belong to long used classes of antimalarial drugs. This review will concisely cover the drugs which are currently in use, and describe the drug candidates which are in clinical evaluation.
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Affiliation(s)
- Martin Schlitzer
- Philipps-Universität, Institut für Pharmazeutische Chemie, Marburg, Germany.
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30
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Schlitzer M. Malaria Chemotherapeutics Part I: History of Antimalarial Drug Development, Currently Used Therapeutics, and Drugs in Clinical Development. ChemMedChem 2007; 2:944-86. [PMID: 17530725 DOI: 10.1002/cmdc.200600240] [Citation(s) in RCA: 179] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
Since ancient times, humankind has had to struggle against the persistent onslaught of pathogenic microorganisms. Nowadays, malaria is still the most important infectious disease worldwide. Considerable success in gaining control over malaria was achieved in the 1950s and 60s through landscaping measures, vector control with the insecticide DDT, and the widespread administration of chloroquine, the most important antimalarial agent ever. In the late 1960s, the final victory over malaria was believed to be within reach. However, the parasites could not be eradicated because they developed resistance against the most widely used and affordable drugs of that time. Today, cases of malaria infections are on the rise and have reached record numbers. This review gives a short description of the malaria disease, briefly addresses the history of antimalarial drug development, and focuses on drugs currently available for malaria therapy. The present knowledge regarding their mode of action and the mechanisms of resistance are explained, as are the attempts made by numerous research groups to overcome the resistance problem within classes of existing drugs and in some novel classes. Finally, this review covers all classes of antimalarials for which at least one drug candidate is in clinical development. Antimalarial agents that are solely in early development stages will be addressed in a separate review.
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Affiliation(s)
- Martin Schlitzer
- Institut für Pharmazeutische Chemie, Philipps-Universität Marburg, Marbacher Weg 6, 35032 Marburg, Germany.
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31
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Abstract
Malaria remains an important cause of global morbidity and mortality. As antimalarial drug resistance escalates, new safe and effective medications are necessary to prevent and treat malarial infection. Tafenoquine is an 8-aminoquinoline antimalarial that is presently under development. It has a long half-life of approximately 14 days and is generally safe and well tolerated, although it cannot be used in pregnant women and individuals who are deficient in the enzyme glucose-6-phosphate dehydrogenase. In well-designed studies, tafenoquine was highly effective in both the radical cure of relapsing malaria and causal prophylaxis of Plasmodium vivax and P. falciparum infections with protective efficacies of > or = 90%. Given its causal activity and safety profile, tafenoquine represents a potentially exciting alternative to standard agents for the prevention and radical cure of malaria.
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Affiliation(s)
- Maryanne Crockett
- The Hospital for Sick Children, Division of Infectious Diseases, 555 University Avenue, Toronto, M5G 1X8, Canada.
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