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Lek D, Tsai YC, Hirano J, Sovannaroth S, Bunreth V, Vonn P, Vannthen O, Bunkea T, Samphornarann T, Sokomar N, Sarath M, Kheang ST, Wong E, Burbach MK, Hughes J, Rekol H. Radical cure for Plasmodium vivax malaria after G6PD qualitative testing in four provinces in Cambodia, results from Phase I implementation. Malar J 2024; 23:56. [PMID: 38395925 PMCID: PMC10893713 DOI: 10.1186/s12936-024-04884-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2023] [Accepted: 02/16/2024] [Indexed: 02/25/2024] Open
Abstract
BACKGROUND Cambodia aims to eliminate all forms of malaria by 2025. In 2020, 90% of all malaria cases were Plasmodium vivax. Thus, preventing P. vivax and relapse malaria is a top priority for elimination. 14-day primaquine, a World Health Organization-recommended radical cure treatment regimen, specifically targets dormant hypnozoites in the liver to prevent relapse. Cambodia introduced P. vivax radical cure with primaquine after glucose-6-phosphate dehydrogenase (G6PD) qualitative testing in 2019. This paper presents Cambodia's radical cure Phase I implementation results and assesses the safety, effectiveness, and feasibility of the programme prior to nationwide scale up. METHODS Phase I implementation was carried out in 88 select health facilities (HFs) across four provinces. Males over 20kgs with confirmed P. vivax or mixed (P. vivax and Plasmodium falciparum) infections were enrolled. A descriptive analysis evaluated the following: successful referral to health facilities, G6PD testing results, and self-reported 14-day treatment adherence. P. vivax incidence was compared before and after radical cure rollout and a controlled interrupted time series analysis compared the estimated relapse rate between implementation and non-implementation provinces before and after radical cure. RESULTS In the 4 provinces from November 2019 to December 2020, 3,239 P. vivax/mixed infections were reported, 1,282 patients underwent G6PD deficiency testing, and 959 patients received radical cure, achieving 29.6% radical cure coverage among all P. vivax/mixed cases and 98.8% coverage among G6PD normal patients. Among those who initiated radical cure, 747 patients (78%) completed treatment. Six patients reported side effects. In implementation provinces, an average 31.8 relapse cases per month were estimated signaling a 90% (286 cases) reduction in relapse compared to what would be expected if radical cure was not implemented. CONCLUSIONS Plasmodium vivax radical cure is a crucial tool for malaria elimination in Cambodia. The high coverage of radical cure initiation and adherence among G6PD normal patients demonstrated the high feasibility of providing radical cure at point of care in Cambodia. Incomplete referral from community to HFs and limited capacity of HF staff to conduct G6PD testing in high burden areas led to lower coverage of G6PD testing. Phase I implementation informed approaches to improve referral completion and patient adherence during the nationwide expansion of radical cure in 2021.
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Affiliation(s)
- Dysoley Lek
- National Center for Parasitology, Entomology, and Malaria Control, Phnom Penh, Cambodia
- School of Public Health, National Institute of Public Health, Phnom Penh, Cambodia
| | - Yu-Cheng Tsai
- Clinton Health Access Initiative, Phnom Penh, Cambodia
| | | | - Siv Sovannaroth
- National Center for Parasitology, Entomology, and Malaria Control, Phnom Penh, Cambodia
| | - Voeurng Bunreth
- Provincial Health Department, Ministry of Health, Phnom Penh, Cambodia
| | - Prak Vonn
- Provincial Health Department, Ministry of Health, Phnom Penh, Cambodia
| | - Or Vannthen
- Provincial Health Department, Ministry of Health, Phnom Penh, Cambodia
| | - Tol Bunkea
- National Center for Parasitology, Entomology, and Malaria Control, Phnom Penh, Cambodia
| | | | - Nguon Sokomar
- Cambodia Malaria Elimination Project, Phnom Penh, Cambodia
| | - Mak Sarath
- Population Services International, Phnom Penh, Cambodia
| | - Soy Ty Kheang
- Center for Health and Social Development, Phnom Penh, Cambodia
- School of Public Health, National Institute of Public Health, Phnom Penh, Cambodia
- Partnership for Vivax Elimination, Phnom Penh, Cambodia
| | - Evelyn Wong
- Clinton Health Access Initiative, Phnom Penh, Cambodia
| | | | - Jayme Hughes
- Clinton Health Access Initiative, Phnom Penh, Cambodia.
| | - Huy Rekol
- National Center for Parasitology, Entomology, and Malaria Control, Phnom Penh, Cambodia
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White NJ. The Antimalarial Activity of Tafenoquine in Falciparum Malaria. Clin Infect Dis 2023; 76:1928-1929. [PMID: 36794679 DOI: 10.1093/cid/ciad079] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2023] [Accepted: 02/15/2023] [Indexed: 02/17/2023] Open
Affiliation(s)
- Nicholas J White
- Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand
- Centre for Tropical Medicine and Global Health, Nuffield Department of Medicine, Oxford University, Oxford, United Kingdom
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Bachhav SS, Taylor M, Martin A, Green JA, Duparc S, Rolfe K, Sharma H, Tan LK, Goyal N. A pharmacometrics approach to assess the feasibility of capillary microsampling to replace venous sampling in clinical studies: Tafenoquine case study. Br J Clin Pharmacol 2023; 89:1187-1197. [PMID: 36199201 DOI: 10.1111/bcp.15554] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2022] [Revised: 08/26/2022] [Accepted: 09/22/2022] [Indexed: 11/28/2022] Open
Abstract
AIM Microsampling has the advantage of smaller blood sampling volume and suitability in vulnerable populations compared to venous sampling in clinical pharmacokinetics studies. Current regulatory guidance requires correlative studies to enable microsampling as a technique. A post hoc population pharmacokinetic (POPPK) approach was utilized to investigate blood capillary microsampling as an alternative to venous sampling. METHODS Pharmacokinetic data from microsampling and venous sampling techniques during a paediatric study evaluating tafenoquine, a single-dose antimalarial for P. vivax, were used. Separate POPPK models were developed and validated based on goodness of fit and visual predictive checks, with pharmacokinetic data obtained via each sampling technique. RESULTS Each POPPK model adequately described tafenoquine pharmacokinetics using a two-compartment model with body weight based on allometric scaling of clearance and volume of distribution. Tafenoquine pharmacokinetic parameter estimates including clearance (3.4 vs 3.7 L/h) were comparable across models with slightly higher interindividual variability (38.3% vs 27%) in capillary microsampling-based data. A bioavailability/bioequivalence comparison demonstrated that the point estimate (90% CI) of capillary microsample versus venous sample model-based individual post hoc estimates for area under the concentration-time curve from time zero to infinity (AUC0-inf ) (100.7%, 98.0-103.5%) and Cmax (79.7%, 76.9-82.5%) met the 80-125% and 70-143% criteria, respectively. Overall, both POPPK models led to the same dose regimen recommendations across weight bins based on achieving target AUC. CONCLUSIONS This analysis demonstrated that a POPPK approach can be employed to assess the performance of alternative pharmacokinetic sampling techniques. This approach provides a robust solution in scenarios where variability in pharmacokinetic data collected via venous sampling and microsampling may not result in a strong linear relationship. The findings also established that microsampling techniques may replace conventional venous sampling methods.
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Affiliation(s)
- Sagar S Bachhav
- Clinical Pharmacology Modeling and Simulation, GSK, Collegeville, PA, USA
| | - Maxine Taylor
- Drug Metabolism and Pharmacokinetics, In Vitro/In Vivo Translation, R&D GSK, Ware, Herts, UK
| | | | | | | | | | | | | | - Navin Goyal
- Clinical Pharmacology Modeling and Simulation, GSK, Collegeville, PA, USA
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Abstract
PURPOSE OF REVIEW This is a review of Plasmodium vivax epidemiology, pathogenesis, disease presentation, treatment and innovations in control and elimination. Here, we examine the recent literature and summarize new advances and ongoing challenges in the management of P. vivax . RECENT FINDINGS P. vivax has a complex life cycle in the human host which impacts disease severity and treatment regimens. There is increasing data for the presence of cryptic reservoirs in the spleen and bone marrow which may contribute to chronic vivax infections and possibly disease severity. Methods to map the geospatial epidemiology of P. vivax chloroquine resistance are advancing, and they will inform local treatment guidelines. P. vivax treatment requires an 8-aminoquinoline to eradicate the dormant liver stage. Evidence suggests that higher doses of 8-aminoquinolines may be needed for radical cure of tropical frequent-relapsing strains. SUMMARY P. vivax is a significant global health problem. There have been recent developments in understanding the complexity of P. vivax biology and optimization of antimalarial therapy. Studies toward the development of best practices for P. vivax control and elimination programs are ongoing.
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Affiliation(s)
- Nazia Khan
- Department of Medicine (Infectious Diseases), Albert Einstein College of Medicine, Bronx, New York
| | - Johanna P. Daily
- Department of Medicine (Infectious Diseases), Albert Einstein College of Medicine, Bronx, New York
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5
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Flaherty S, Strauch P, Maktabi M, Pybus BS, Reichard G, Walker LA, Rochford R. Mechanisms of 8-aminoquinoline induced haemolytic toxicity in a G6PDd humanized mouse model. J Cell Mol Med 2022; 26:3675-3686. [PMID: 35665597 PMCID: PMC9258708 DOI: 10.1111/jcmm.17362] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2022] [Revised: 03/29/2022] [Accepted: 04/05/2022] [Indexed: 11/29/2022] Open
Abstract
Primaquine (PQ) and Tafenoquine (TQ) are clinically important 8‐aminoquinolines (8‐AQ) used for radical cure treatment of P. vivax infection, known to target hepatic hypnozoites. 8‐AQs can trigger haemolytic anaemia in individuals with glucose‐6‐phosphate dehydrogenase deficiency (G6PDd), yet the mechanisms of haemolytic toxicity remain unknown. To address this issue, we used a humanized mouse model known to predict haemolytic toxicity responses in G6PDd human red blood cells (huRBCs). To evaluate the markers of eryptosis, huRBCs were isolated from mice 24–48 h post‐treatment and analysed for effects on phosphatidylserine (PS), intracellular reactive oxygen species (ROS) and autofluorescence. Urinalysis was performed to evaluate the occurrence of intravascular and extravascular haemolysis. Spleen and liver tissue harvested at 24 h and 5–7 days post‐treatment were stained for the presence of CD169+ macrophages, F4/80+ macrophages, Ter119+ mouse RBCs, glycophorin A+ huRBCs and murine reticulocytes (muRetics). G6PDd‐huRBCs from PQ/TQ treated mice showed increased markers for eryptosis as early as 24 h post‐treatment. This coincided with an early rise in levels of muRetics. Urinalysis revealed concurrent intravascular and extravascular haemolysis in response to PQ/TQ. Splenic CD169+ macrophages, present in all groups at day 1 post‐dosing were eliminated by days 5–7 in PQ/TQ treated mice only, while liver F4/80 macrophages and iron deposits increased. Collectively, our data suggest 8‐AQ treated G6PDd‐huRBCs have early physiological responses to treatment, including increased markers for eryptosis indicative of oxidative stress, resulting in extramedullary haematopoiesis and loss of splenic CD169+ macrophages, prompting the liver to act as the primary site of clearance.
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Affiliation(s)
- Siobhan Flaherty
- Department of Immunology and Microbiology, The University of Colorado School of Medicine, Aurora, Colorado, USA
| | - Pamela Strauch
- Department of Immunology and Microbiology, The University of Colorado School of Medicine, Aurora, Colorado, USA
| | - Mahdi Maktabi
- Department of Immunology and Microbiology, The University of Colorado School of Medicine, Aurora, Colorado, USA
| | - Brandon S Pybus
- Division of Experimental Therapeutics, Walter Reed Army Institute of Research, Silver Spring, Maryland, USA
| | - Gregory Reichard
- Department of Drug Discovery, Experimental Therapeutics Branch, Walter Reed Army Institute of Research, Silver Spring, Maryland, USA
| | - Larry A Walker
- National Center for Natural Products Research and Department of Biomolecular Sciences, School of Pharmacy, The University of Mississippi, University, Mississippi, USA
| | - Rosemary Rochford
- Department of Immunology and Microbiology, The University of Colorado School of Medicine, Aurora, Colorado, USA
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Abstract
Introduction: A century-long history in 8-aminoquinolines, the only anti-malaria drug class preventing malaria relapse, has resulted in the approval of tafenoquine by the U.S. Food and Drug Administration (FDA) and the Australian Therapeutic Goods Administration (TGA) and to date registration in Brazil and Thailand. Tafenoquine is an alternative anti-relapse treatment for vivax malaria and malaria prophylaxis. It should not be given in pregnancy, during lactation of infants with glucose-6-phosphate dehydrogenase (G6PD) unknown or deficient status, and in those with G6PD deficiency or psychiatric illness.Areas covered: This systematic review assesses tafenoquine associated adverse events in English-language, human clinical trials. Meta-analysis of commonly reported adverse events was conducted and grouped by comparison arms.Expert opinion: Tafenoquine, either for radical cure or prophylaxis, is generally well tolerated in adults. There is no convincing evidence for neurologic, ophthalmic, and cardiac toxicities. Psychotic disorder which has been attributed to higher doses is a contraindication for the chemoprophylaxis indication and psychiatric illness is a warning for the radical cure indication. Pregnancy assessment and quantitative G6PD testing are required. The optimal radical curative regimen including the tafenoquine dose along with its safety for parts of Southeast Asia, South America, and Oceania needs further assessment.
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Affiliation(s)
- Cindy S. Chu
- Shoklo Malaria Research Unit, Faculty of Tropical Medicine, Mahidol University, Mae Sot, Thailand
- Centre for Tropical Medicine and Global Health, Nuffield Department of Medicine, University of Oxford, UK
| | - Jimee Hwang
- U.S. President’s Malaria Initiative, Malaria Branch, Division of Parasitic Diseases and Malaria, Centers for Disease Control and Prevention, Atlanta, GA, USA
- Global Health Group, University of California San Francisco, San Francisco, CA, USA
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Oschmann M, Johansson Holm L, Pourghasemi-Lati M, Verho O. Synthesis of Elaborate Benzofuran-2-carboxamide Derivatives through a Combination of 8-Aminoquinoline Directed C-H Arylation and Transamidation Chemistry. Molecules 2020; 25:E361. [PMID: 31952313 PMCID: PMC7024369 DOI: 10.3390/molecules25020361] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2019] [Revised: 01/09/2020] [Accepted: 01/13/2020] [Indexed: 12/20/2022] Open
Abstract
Herein, we present a short and highly modular synthetic route that involves 8-aminoquinoline directed C-H arylation and transamidation chemistry, and which enables access to a wide range of elaborate benzofuran-2-carboxamides. For the directed C-H arylation reactions, Pd catalysis was used to install a wide range of aryl and heteroaryl substituents at the C3 position of the benzofuran scaffold in high efficiency. Directing group cleavage and further diversification of the C3-arylated benzofuran products were then achieved in a single synthetic operation through the utilization of a one-pot, two-step transamidation procedure, which proceeded via the intermediate N-acyl-Boc-carbamates. Given the high efficiency and modularity of this synthetic strategy, it constitutes a very attractive method for generating structurally diverse collections of benzofuran derivatives for small molecule screening campaigns.
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Affiliation(s)
| | | | | | - Oscar Verho
- Arrhenius Laboratory, Department of Organic Chemistry, Stockholm University, SE-106 91 Stockholm, Sweden; (M.O.); (L.J.H.); (M.P.-L.)
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8
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Sattar M, Kumar N, Yadav P, Mandhar Y, Kumar S. 8-Aminoquinoline-Assisted Synthesis and Crystal Structure Studies of Ferrocenyl Aryl Sulfones. Chem Asian J 2019; 14:4807-4813. [PMID: 31659838 DOI: 10.1002/asia.201901334] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2019] [Revised: 10/25/2019] [Indexed: 01/05/2023]
Abstract
A copper-catalyzed 8-aminoquinoline-directed oxidative cross-coupling of the C-H bond of ferrocene with sodium arylsulfinates has been achieved. The robust copper catalyst tolerates a range of methyl, tert-butyl, bromo, chloro, iodo and nitro functional groups in the phenyl ring, and set the stage for the synthesis of substituted ferrocene sulfones. Furthermore, X-ray crystal structure study on several ferrocenyl sulfones reveals the tetrahedral geometry around sulfur; interestingly, the O-S-O angle is larger than the electropositive substituent C-S-C angle which could be explained by Bent's rule. Further, unusual intramolecular O(S)⋅⋅⋅N(amide) short contacts (2.925-3) and O(S)⋅⋅⋅C=O were also noticed in ferrocenyl sulfones.
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Affiliation(s)
- Moh Sattar
- Department of Chemistry, Indian Institute of Science Education and Research, Bhopal, Bhopal Bypass Road, Bhauri, Bhopal, Madhya Pradesh, 462066, India
| | - Nitin Kumar
- Department of Chemistry, Indian Institute of Science Education and Research, Bhopal, Bhopal Bypass Road, Bhauri, Bhopal, Madhya Pradesh, 462066, India
| | - Prateek Yadav
- Department of Chemistry, Indian Institute of Science Education and Research, Bhopal, Bhopal Bypass Road, Bhauri, Bhopal, Madhya Pradesh, 462066, India
| | - Yogesh Mandhar
- Department of Chemistry, Indian Institute of Science Education and Research, Bhopal, Bhopal Bypass Road, Bhauri, Bhopal, Madhya Pradesh, 462066, India
| | - Sangit Kumar
- Department of Chemistry, Indian Institute of Science Education and Research, Bhopal, Bhopal Bypass Road, Bhauri, Bhopal, Madhya Pradesh, 462066, India
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9
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Hamerly T, Tweedell RE, Hritzo B, Nyasembe VO, Tekwani BL, Nanayakkara NPD, Walker LA, Dinglasan RR. NPC1161B, an 8-Aminoquinoline Analog, Is Metabolized in the Mosquito and Inhibits Plasmodium falciparum Oocyst Maturation. Front Pharmacol 2019; 10:1265. [PMID: 31708786 PMCID: PMC6823860 DOI: 10.3389/fphar.2019.01265] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2019] [Accepted: 09/30/2019] [Indexed: 11/26/2022] Open
Abstract
Malaria is a major global health threat, with nearly half the world’s population at risk of infection. Given the recently described delayed clearance of parasites by artemisinin-combined therapies, new antimalarials are needed to facilitate the global effort toward elimination and eradication. NPC1161 is an 8-aminoquinoline that is derived from primaquine with an improved therapeutic profile compared to the parent compound. The (R)-(−) enantiomer (NPC1161B) has a lower effective dose that results in decreased toxic side effects such as hemolysis compared to the (S)-(+)-enantiomer, making it a promising compound for consideration for clinical development. We explored the effect of NPC1161B on Plasmodium falciparum oocyst and sporozoite development to evaluate its potential transmission-blocking activity viz. its ability to cure mosquitoes of an ongoing infection. When mosquitoes were fed NPC1161B 4 days after P. falciparum infection, we observed that total oocyst numbers were not affected by NPC1161B treatment. However, the sporozoite production capacity of the oocysts was impaired, and salivary gland sporozoite infections were completely blocked, rendering the mosquitoes non-infectious. Importantly, NPC1161B did not require prior liver metabolism for its efficacy as is required in mammalian systems, suggesting that an alternative metabolite is produced in the mosquito that is active against the parasite. We performed liquid chromatography–mass spectrometry (LC-MS)/MS analysis of methanol extracts from the midguts of mosquitoes fed on an NPC1161B (434.15 m/z)-treated blood meal and identified a compound with a mass of 520.2 m/z, likely a conjugate of NPC1161B or an oxidized metabolite. These findings establish NPC1161B, and potentially its metabolites, as transmission-blocking candidates for the treatment of P. falciparum.
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Affiliation(s)
- Timothy Hamerly
- W. Harry Feinstone Department of Molecular Microbiology and Immunology, Johns Hopkins Bloomberg School of Public Health, Baltimore, MD, United States.,Department of Infectious Diseases & Immunology, Emerging Pathogens Institute, University of Florida, Gainesville, FL, United States
| | - Rebecca E Tweedell
- W. Harry Feinstone Department of Molecular Microbiology and Immunology, Johns Hopkins Bloomberg School of Public Health, Baltimore, MD, United States.,Department of Infectious Diseases & Immunology, Emerging Pathogens Institute, University of Florida, Gainesville, FL, United States
| | - Bernadette Hritzo
- W. Harry Feinstone Department of Molecular Microbiology and Immunology, Johns Hopkins Bloomberg School of Public Health, Baltimore, MD, United States
| | - Vincent O Nyasembe
- Department of Infectious Diseases & Immunology, Emerging Pathogens Institute, University of Florida, Gainesville, FL, United States
| | - Babu L Tekwani
- Division of Drug Discovery, Department of Infectious Diseases, Southern Research, Birmingham, AL, United States
| | - N P Dhammika Nanayakkara
- National Center for Natural Products Research, University of Mississippi School of Pharmacy, Oxford, MS, United States
| | - Larry A Walker
- Division of Drug Discovery, Department of Infectious Diseases, Southern Research, Birmingham, AL, United States
| | - Rhoel R Dinglasan
- W. Harry Feinstone Department of Molecular Microbiology and Immunology, Johns Hopkins Bloomberg School of Public Health, Baltimore, MD, United States.,Department of Infectious Diseases & Immunology, Emerging Pathogens Institute, University of Florida, Gainesville, FL, United States
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Hounkpatin AB, Kreidenweiss A, Held J. Clinical utility of tafenoquine in the prevention of relapse of Plasmodium vivax malaria: a review on the mode of action and emerging trial data. Infect Drug Resist 2019; 12:553-570. [PMID: 30881061 PMCID: PMC6411314 DOI: 10.2147/idr.s151031] [Citation(s) in RCA: 29] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023] Open
Abstract
Tafenoquine is an 8-aminoquinoline with activity against all human life cycle stages of Plasmodium vivax, including dormant liver stages – so called hypnozoites. Its long half-life of ~15 days is allowing for a single exposure regimen. It has been under development since 1980 and received approval by the US Food and Drug Administration in summer 2018 as an anti-relapse drug for P. vivax malaria in patients aged 16 years and older and for prophylaxis of malaria caused by any Plasmodium species in adults. Prior to tafenoquine administration, glucose-6-phosphate dehydrogenase (G6PD) deficiency needs to be excluded by testing. Individuals with a deficient G6PD activity are at risk of tafenoquine-induced hemolysis – as is the case for primaquine, the mainstay drug for P. vivax radical cure. A wealth of clinical studies have been conducted and are still ongoing to assess the safety, tolerability, and efficacy of tafenoquine. This review focuses on data emerging from the latest clinical trials on P. vivax radical cure with tafenoquine, the key studies for regulatory approval of tafenoquine, and elucidates the latest hypothesis on the mode of action.
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Affiliation(s)
- Aurore B Hounkpatin
- Institute of Tropical Medicine, Eberhard Karls University Tübingen, Tübingen, Germany, .,German Centre for Infection Research, Partner Site Tübingen, Tübingen, Germany, .,Centre de Recherches Médicales de Lambaréné (CERMEL), Lambaréné, Gabon,
| | - Andrea Kreidenweiss
- Institute of Tropical Medicine, Eberhard Karls University Tübingen, Tübingen, Germany, .,German Centre for Infection Research, Partner Site Tübingen, Tübingen, Germany,
| | - Jana Held
- Institute of Tropical Medicine, Eberhard Karls University Tübingen, Tübingen, Germany, .,German Centre for Infection Research, Partner Site Tübingen, Tübingen, Germany, .,Centre de Recherches Médicales de Lambaréné (CERMEL), Lambaréné, Gabon,
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11
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Berman J, Brown T, Dow G, Toovey S. Tafenoquine and primaquine do not exhibit clinical neurologic signs associated with central nervous system lesions in the same manner as earlier 8-aminoquinolines. Malar J 2018; 17:407. [PMID: 30400893 PMCID: PMC6219089 DOI: 10.1186/s12936-018-2555-3] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2018] [Accepted: 10/27/2018] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Tafenoquine was recently approved for Plasmodium vivax radical cure (KRINTAFEL™) and malaria prevention (ARAKODA™). METHODS A review of the non-clinical and clinical literature was conducted to assess whether tafenoquine (and primaquine) exhibit the same neurologic lesions and associated clinical signs as earlier 8-aminoquinolines, as has been alleged in recent opinion pieces. RESULTS Plasmocid, pamaquine and pentaquine damage specific neuro-anatomical structures in Rhesus monkeys and humans leading to corresponding deficits in neurologic function. Neurologic therapeutic indices for these 3 drugs calculated based on monkey data were well correlated with human data. Despite 60 years of use, there is no evidence that primaquine exhibits similar neurotoxicity in humans. DISCUSSION/CONCLUSIONS Extrapolation of data from Rhesus monkeys to humans, and the available clinical data, suggest that tafenoquine also does not exhibit pamaquine, pentaquine or plasmocid-like clinical neurologic signs in humans.
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Affiliation(s)
| | - Tracey Brown
- Clinical Network Services Pty Ltd, 88/4 Jephson Road, Toowong, 4066 Queensland Australia
| | - Geoffrey Dow
- 60°Pharmaceuticals LLC, 1025 Connecticut Ave NW, Suite 1000, Washington, DC 20036 USA
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12
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Thakkar N, Green JA, Koh GCKW, Duparc S, Tenero D, Goyal N. Population Pharmacokinetics of Tafenoquine, a Novel Antimalarial. Antimicrob Agents Chemother 2018; 62:e00711-18. [PMID: 30201820 DOI: 10.1128/AAC.00711-18] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2018] [Accepted: 09/02/2018] [Indexed: 12/18/2022] Open
Abstract
Tafenoquine is a novel 8-aminoquinoline antimalarial drug recently approved by the U.S. Food and Drug Administration (FDA) for the radical cure of acute Plasmodium vivax malaria, which is the first new treatment in almost 60 years. Tafenoquine is a novel 8-aminoquinoline antimalarial drug recently approved by the U.S. Food and Drug Administration (FDA) for the radical cure of acute Plasmodium vivax malaria, which is the first new treatment in almost 60 years. A population pharmacokinetic (POP PK) analysis was conducted with tafenoquine exposure data obtained following oral administration from 6 clinical studies in phase 1 through phase 3 with a nonlinear mixed effects modeling approach. The impacts of patient demographics, baseline characteristics, and extrinsic factors, such as formulation, were evaluated. Model performance was assessed using techniques such as bootstrapping, visual predictive checks, and external data validation from a phase 3 study not used in model fitting and parameter estimation. Based on the analysis, the systemic pharmacokinetics of tafenoquine were adequately described using a two-compartment model. The final POP PK model included body weight (allometric scaling) on apparent oral and intercompartmental clearance (CL/F and Q/F, respectively), apparent volume of distribution for central and peripheral compartments (V2/F and V3/F, respectively), formulation on systemic bioavailability (F1) and absorption rate constant (Ka), and health status on apparent volume of distribution. The key tafenoquine population parameter estimates were 2.96 liters/h for CL/F and 915 liters for V2/F in P. vivax-infected subjects. Additionally, the analyses demonstrated no clinically relevant difference in relative bioavailability across the capsule and tablet formulations administered in these clinical studies. In conclusion, a POP PK model for tafenoquine was developed. Clinical trial simulations based on this model supported bridging the exposures across two different formulations. This POP PK model can be applied to aid and perform clinical trial simulations in other scenarios and populations, such as pediatric populations.
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Avula B, Tekwani BL, Chaurasiya ND, Fasinu P, Dhammika Nanayakkara NP, Bhandara Herath HMT, Wang YH, Bae JY, Khan SI, Elsohly MA, McChesney JD, Zimmerman PA, Khan IA, Walker LA. Metabolism of primaquine in normal human volunteers: investigation of phase I and phase II metabolites from plasma and urine using ultra-high performance liquid chromatography-quadrupole time-of-flight mass spectrometry. Malar J 2018; 17:294. [PMID: 30103751 PMCID: PMC6090659 DOI: 10.1186/s12936-018-2433-z] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2018] [Accepted: 07/30/2018] [Indexed: 12/16/2022] Open
Abstract
BACKGROUND Primaquine (PQ), an 8-aminoquinoline, is the only drug approved by the United States Food and Drug Administration for radical cure and prevention of relapse in Plasmodium vivax infections. Knowledge of the metabolism of PQ is critical for understanding the therapeutic efficacy and hemolytic toxicity of this drug. Recent in vitro studies with primary human hepatocytes have been useful for developing the ultra high-performance liquid chromatography coupled with high-resolution mass spectrometric (UHPLC-QToF-MS) methods for simultaneous determination of PQ and its metabolites generated through phase I and phase II pathways for drug metabolism. METHODS These methods were further optimized and applied for phenotyping PQ metabolites from plasma and urine from healthy human volunteers treated with single 45 mg dose of PQ. Identity of the metabolites was predicted by MetaboLynx using LC-MS/MS fragmentation patterns. Selected metabolites were confirmed with appropriate standards. RESULTS Besides PQ and carboxy PQ (cPQ), the major plasma metabolite, thirty-four additional metabolites were identified in human plasma and urine. Based on these metabolites, PQ is viewed as metabolized in humans via three pathways. Pathway 1 involves direct glucuronide/glucose/carbamate/acetate conjugation of PQ. Pathway 2 involves hydroxylation (likely cytochrome P450-mediated) at different positions on the quinoline ring, with mono-, di-, or even tri-hydroxylations possible, and subsequent glucuronide conjugation of the hydroxylated metabolites. Pathway 3 involves the monoamine oxidase catalyzed oxidative deamination of PQ resulting in formation of PQ-aldehyde, PQ alcohol and cPQ, which are further metabolized through additional phase I hydroxylations and/or phase II glucuronide conjugations. CONCLUSION This approach and these findings augment our understanding and provide comprehensive view of pathways for PQ metabolism in humans. These will advance the clinical studies of PQ metabolism in different populations for different therapeutic regimens and an understanding of the role these play in PQ efficacy and safety outcomes, and their possible relation to metabolizing enzyme polymorphisms.
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Affiliation(s)
- Bharathi Avula
- National Center for Natural Products Research, School of Pharmacy, The University of Mississippi, University, MS, 38677, USA
| | - Babu L Tekwani
- National Center for Natural Products Research, School of Pharmacy, The University of Mississippi, University, MS, 38677, USA.
| | - Narayan D Chaurasiya
- National Center for Natural Products Research, School of Pharmacy, The University of Mississippi, University, MS, 38677, USA
| | - Pius Fasinu
- National Center for Natural Products Research, School of Pharmacy, The University of Mississippi, University, MS, 38677, USA
| | - N P Dhammika Nanayakkara
- National Center for Natural Products Research, School of Pharmacy, The University of Mississippi, University, MS, 38677, USA
| | - H M T Bhandara Herath
- National Center for Natural Products Research, School of Pharmacy, The University of Mississippi, University, MS, 38677, USA
| | - Yan-Hong Wang
- National Center for Natural Products Research, School of Pharmacy, The University of Mississippi, University, MS, 38677, USA
| | - Ji-Yeong Bae
- National Center for Natural Products Research, School of Pharmacy, The University of Mississippi, University, MS, 38677, USA
| | - Shabana I Khan
- National Center for Natural Products Research, School of Pharmacy, The University of Mississippi, University, MS, 38677, USA
| | - Mahmoud A Elsohly
- National Center for Natural Products Research, School of Pharmacy, The University of Mississippi, University, MS, 38677, USA
| | | | - Peter A Zimmerman
- Center for Global Health & Diseases, Case Western Reserve University Cleveland, Ohio, 44106, USA
| | - Ikhlas A Khan
- National Center for Natural Products Research, School of Pharmacy, The University of Mississippi, University, MS, 38677, USA
| | - Larry A Walker
- National Center for Natural Products Research, School of Pharmacy, The University of Mississippi, University, MS, 38677, USA
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Abstract
Oxidative agents can cause acute haemolytic anaemia in persons with G6PD deficiency. Understanding the relationship between G6PD genotype and the phenotypic expression of the enzyme deficiency is necessary so that severe haemolysis can be avoided. The patterns of oxidative haemolysis have been well described in G6PD deficient hemizygous males and homozygous females; and haemolysis in the proportionally more numerous heterozygous females has been documented mainly following consumption of fava beans and more recently dapsone. It has long been known that 8-aminoquinolines, notably primaquine and tafenoquine, cause acute haemolysis in G6PD deficiency. To support wider use of primaquine in Plasmodium vivax elimination, more data are needed on the haemolytic consequences of 8-aminoquinolines in G6PD heterozygous females. Two recent studies (in 2017) have provided precisely such data; and the need has emerged for the development of point of care quantitative testing of G6PD activity. Another priority is exploring alternative 8-aminoquinoline dosing regimens that are practical and improve safety in G6PD deficient individuals.
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Affiliation(s)
- Cindy S Chu
- Shoklo Malaria Research Unit, Faculty of Tropical Medicine, Mahidol-Oxford Tropical Medicine Research Unit, Mahidol University, Mae Sot, Thailand.
- Centre for Tropical Medicine and Global Health, Nuffield Department of Medicine, University of Oxford, Oxford, UK.
| | - Germana Bancone
- Shoklo Malaria Research Unit, Faculty of Tropical Medicine, Mahidol-Oxford Tropical Medicine Research Unit, Mahidol University, Mae Sot, Thailand
- Centre for Tropical Medicine and Global Health, Nuffield Department of Medicine, University of Oxford, Oxford, UK
| | - François Nosten
- Shoklo Malaria Research Unit, Faculty of Tropical Medicine, Mahidol-Oxford Tropical Medicine Research Unit, Mahidol University, Mae Sot, Thailand
- Centre for Tropical Medicine and Global Health, Nuffield Department of Medicine, University of Oxford, Oxford, UK
| | - Nicholas J White
- Mahidol-Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand
- Centre for Tropical Medicine and Global Health, Nuffield Department of Medicine, University of Oxford, Oxford, UK
| | - Lucio Luzzatto
- Department of Haematology, Muhimbili University of Health and Allied Sciences, Dar-es-Salaam, Tanzania
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Nqoro X, Tobeka N, Aderibigbe BA. Quinoline-Based Hybrid Compounds with Antimalarial Activity. Molecules 2017; 22:molecules22122268. [PMID: 29257067 PMCID: PMC6149725 DOI: 10.3390/molecules22122268] [Citation(s) in RCA: 92] [Impact Index Per Article: 13.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2017] [Revised: 12/11/2017] [Accepted: 12/11/2017] [Indexed: 01/05/2023] Open
Abstract
The application of quinoline-based compounds for the treatment of malaria infections is hampered by drug resistance. Drug resistance has led to the combination of quinolines with other classes of antimalarials resulting in enhanced therapeutic outcomes. However, the combination of antimalarials is limited by drug-drug interactions. In order to overcome the aforementioned factors, several researchers have reported hybrid compounds prepared by reacting quinoline-based compounds with other compounds via selected functionalities. This review will focus on the currently reported quinoline-based hybrid compounds and their preclinical studies.
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Affiliation(s)
- Xhamla Nqoro
- Department of Chemistry, University of Fort Hare, Alice Campus, Alice 5700, Eastern Cape, South Africa.
| | - Naki Tobeka
- Department of Chemistry, University of Fort Hare, Alice Campus, Alice 5700, Eastern Cape, South Africa.
| | - Blessing A Aderibigbe
- Department of Chemistry, University of Fort Hare, Alice Campus, Alice 5700, Eastern Cape, South Africa.
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16
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Novitt-Moreno A, Ransom J, Dow G, Smith B, Read LT, Toovey S. Tafenoquine for malaria prophylaxis in adults: An integrated safety analysis. Travel Med Infect Dis 2017; 17:19-27. [PMID: 28495354 DOI: 10.1016/j.tmaid.2017.05.008] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2017] [Revised: 05/05/2017] [Accepted: 05/06/2017] [Indexed: 11/24/2022]
Abstract
BACKGROUND Tafenoquine is a new prophylactic antimalarial drug. The current analysis presents an integrated safety assessment of the Tafenoquine Anticipated Clinical Regimen (Tafenoquine ACR) from 5 clinical trials, including 1 conducted in deployed military personnel and 4 in non-deployed residents, which also incorporated placebo and mefloquine comparator groups. METHODS Adverse events (AEs) were coded according to the Medical Dictionary for Regulatory Activities (MedDRA®, Version 15.0) and summarized. Among all subjects who had received the Tafenoquine ACR, safety findings were compared for subjects who were deployed military personnel from the Australian Defence Force (Deployed ADF) versus non-deployed residents (Resident Non-ADF). RESULTS The incidence of at least one AE was 80.6%, 64.1%, 67.6% and 94.9% in the mefloquine, placebo, tafenoquine Resident Non-ADF and tafenoquine Deployed ADF groups, respectively. The latter group had a higher incidence of AEs related to military deployment. AEs that occurred at ≥ 1% incidence in both tafenoquine sub-groups and at a higher frequency than placebo included diarrhea, nausea, vomiting, gastroenteritis, nasopharyngeal tract infections, and back/neck pain. CONCLUSIONS Weekly administration of tafenoquine for up to six months increased the incidence of gastrointestinal AEs, certain infections, and back/neck pain, but not the overall incidence of AEs versus placebo. CLINICAL TRIAL REGISTRATION NUMBERS/CLINICALTRIALS. GOV IDENTIFIERS NCT02491606; NCT02488980; NCT02488902.
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17
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Abstract
Introduction: Relapses are important contributors to illness and morbidity in Plasmodium vivax and P. ovale infections. Relapse prevention (radical cure) with primaquine is required for optimal management, control and ultimately elimination of Plasmodium vivax malaria. A review was conducted with publications in English, French, Portuguese and Spanish using the search terms ‘P. vivax’ and ‘relapse’. Areas covered: Hypnozoites causing relapses may be activated weeks or months after initial infection. Incidence and temporal patterns of relapse varies geographically. Relapses derive from parasites either genetically similar or different from the primary infection indicating that some derive from previous infections. Malaria illness itself may activate relapse. Primaquine is the only widely available treatment for radical cure. However, it is often not given because of uncertainty over the risks of primaquine induced haemolysis when G6PD deficiency testing is unavailable. Recommended dosing of primaquine for radical cure in East Asia and Oceania is 0.5 mg base/kg/day and elsewhere is 0.25 mg base/kg/day. Alternative treatments are under investigation. Expert commentary: Geographic heterogeneity in relapse patterns and chloroquine susceptibility of P. vivax, and G6PD deficiency epidemiology mean that radical treatment should be given much more than it is today. G6PD testing should be made widely available so primaquine can be given more safely.
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Affiliation(s)
- Cindy S Chu
- a Shoklo Malaria Research Unit, Mahidol-Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine , Mahidol University , Mae Sot , Thailand.,b Mahidol-Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine , Mahidol University , Bangkok , Thailand
| | - Nicholas J White
- b Mahidol-Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine , Mahidol University , Bangkok , Thailand.,c Centre for Tropical Medicine and Global Health, Nuffield Department of Medicine , University of Oxford , Oxford , UK
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18
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Segretti MCF, Vallerini GP, Brochier C, Langley B, Wang L, Hancock WW, Kozikowski AP. Thiol-Based Potent and Selective HDAC6 Inhibitors Promote Tubulin Acetylation and T-Regulatory Cell Suppressive Function. ACS Med Chem Lett 2015; 6:1156-61. [PMID: 26617971 DOI: 10.1021/acsmedchemlett.5b00303] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2015] [Accepted: 10/05/2015] [Indexed: 01/20/2023] Open
Abstract
Several new mercaptoacetamides were synthesized and studied as HDAC6 inhibitors. One compound, 2b, bearing an aminoquinoline cap group, was found to show 1.3 nM potency at HDAC6, with >3000-fold selectivity over HDAC1. 2b also showed excellent efficacy at increasing tubulin acetylation in rat primary cortical cultures, inducing a 10-fold increase in acetylated tubulin at 1 μM. To assess possible therapeutic effects, compounds were assayed for their ability to increase T-regulatory (Treg) suppressive function. Some but not all of the compounds increased Treg function, and thereby decreased conventional T cell activation and proliferation in vitro.
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Affiliation(s)
- Mariana C. F. Segretti
- Department of Medicinal Chemistry & Pharmacognosy, University of Illinois at Chicago, Chicago, Illinois 60612, United States
| | - Gian Paolo Vallerini
- Department of Medicinal Chemistry & Pharmacognosy, University of Illinois at Chicago, Chicago, Illinois 60612, United States
| | - Camille Brochier
- Burke-Cornell Medical Research Institute, White Plains, New York 10605, United States
- Department of Neurology and Neuroscience, Weill Medical College of Cornell University, New York, New York 10065, United States
| | - Brett Langley
- Burke-Cornell Medical Research Institute, White Plains, New York 10605, United States
- Department of Neurology and Neuroscience, Weill Medical College of Cornell University, New York, New York 10065, United States
| | - Liqing Wang
- Department
of Pathology and Laboratory Medicine, Division of Transplant Immunology, Children’s Hospital of Philadelphia and University of Pennsylvania, Philadelphia, Pennsylvania 19104, United States
| | - Wayne W. Hancock
- Department
of Pathology and Laboratory Medicine, Division of Transplant Immunology, Children’s Hospital of Philadelphia and University of Pennsylvania, Philadelphia, Pennsylvania 19104, United States
| | - Alan P. Kozikowski
- Department of Medicinal Chemistry & Pharmacognosy, University of Illinois at Chicago, Chicago, Illinois 60612, United States
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Chen I, Poirot E, Newman M, Kandula D, Shah R, Hwang J, Cohen JM, Gosling R, Rooney L. An assessment of the supply, programmatic use, and regulatory issues of single low-dose primaquine as a Plasmodium falciparum gametocytocide for sub-Saharan Africa. Malar J 2015; 14:204. [PMID: 25971688 PMCID: PMC4446184 DOI: 10.1186/s12936-015-0714-3] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2015] [Accepted: 04/23/2015] [Indexed: 12/02/2022] Open
Abstract
BACKGROUND Global ambitions to eliminate malaria are intensifying, underscoring a critical need for transmission blocking tools. In 2012, the WHO recommended the use of 0.25 mg/kg of single low-dose (SLD) primaquine to stop Plasmodium falciparum transmission. To ensure the availability of SLD primaquine to countries in need of this tool, more information on the supply, programmatic, and regulatory barriers to the rollout of SLD primaquine is required. METHODS Challenges to the rollout of SLD primaquine in sub-Saharan Africa were established through semi-structured qualitative interviews with three primaquine manufacturers, 43 key informants from Ethiopia, Senegal, Swaziland, Zambia, and Tanzania, and 16 malaria research experts. RESULTS Sanofi and Remedica are the only two sources of SRA-approved primaquine suitable for procurement by international donors. Neither manufacturer produces primaquine tablet strengths suitable for the transmission blocking indication. In-country key informants revealed that the WHO weight-based recommendation to use SLD primaquine is challenging to implement in actual field settings. Malaria programmes expressed safety concerns of SLD primaquine use in individuals with glucose-6-phosphate dehydrogenase (G6PD) deficiency, as well as potential interactions between primaquine and co-morbidities, and drug-drug interactions with HIV and/or tuberculosis treatments. Regulatory processes are a major barrier to the rollout of SLD primaquine, requiring multiple steps at both the country and global level. Despite these barriers, demand for SLD primaquine is growing, and malaria researchers are interested in primaquine deployment through mass screen and treat and/or mass drug administration campaigns. CONCLUSION Demand for primaquine as a transmission blocking agent is growing rapidly yet multiple barriers to SLD primaquine use exist. Research is needed to define the therapeutic dose range, which will guide dosing regimens in the field, inform the development of new, lower strength primaquine tablets and/or formulation(s), and allay programmatic safety concerns in individuals with G6PD deficiency. Potential interactions between primaquine and co-morbidities and treatments should be explored. To minimize regulatory delays, countries need to prepare for product registration at an early stage, WHO prequalification for suitable primaquine tablet strengths and/or new formulations should be sought, and in the meanwhile only Stringent Regulatory Authority (SRA)-approved primaquine should be used.
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Affiliation(s)
- Ingrid Chen
- Global Health Sciences, University of California, San Francisco, 550 16th Street, 3rd Floor, San Francisco, CA, 94158, USA.
| | - Eugenie Poirot
- Global Health Sciences, University of California, San Francisco, 550 16th Street, 3rd Floor, San Francisco, CA, 94158, USA.
| | - Mark Newman
- Clinton Health Access Initiative, Boston, MA, USA.
| | | | - Renee Shah
- Clinton Health Access Initiative, Boston, MA, USA.
| | - Jimee Hwang
- Global Health Sciences, University of California, San Francisco, 550 16th Street, 3rd Floor, San Francisco, CA, 94158, USA.
- Malaria Branch, Centers for Disease Control and Prevention, 1600 Clifton Rd, Atlanta, GA, USA.
| | | | - Roly Gosling
- Global Health Sciences, University of California, San Francisco, 550 16th Street, 3rd Floor, San Francisco, CA, 94158, USA.
| | - Luke Rooney
- Clinton Health Access Initiative, Boston, MA, USA.
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20
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Abstract
Malaria transmission is declining worldwide, leading to a growing interest in strategies to reach elimination and eradication. Insecticide and drug resistance threaten these efforts, driving an interest in the use of gametocytocidal drugs to curb the spread of artemisinin resistance and accelerate the path to malaria elimination. Primaquine is the only marketed drug that can kill mature Plasmodium falciparum gametocytes, which can otherwise contribute to ongoing transmission for long periods of time. While primaquine has been widely used in Asia and the Americas, African countries have little experience with this drug and are reluctant to use primaquine due to a fear of hemolytic side effects. We discuss the underlying knowledge base and motivation to use primaquine as a P. falciparum transmission blocker, revealing that while primaquine implementation can benefit from further study, there remains an overall need for improved transmission-blocking drugs.
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Affiliation(s)
- Ingrid T Chen
- Malaria Elimination Initiative, Global Health Group, University of California, San Francisco, 50 Beale Street, Suite 1200, Box 1224, San Francisco, CA 94105, USA
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21
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Herath HMTB, McChesney JD, Walker LA, Nanayakkara NPD. Synthesis of [13C6]primaquine. J Labelled Comp Radiopharm 2013; 56:341-3. [PMID: 24285435 DOI: 10.1002/jlcr.3039] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2013] [Accepted: 01/26/2013] [Indexed: 11/08/2022]
Abstract
In support of a program to identify toxic metabolites of the antimalarial, primaquine, its [(13)C6] analog was prepared from [(13)C6] anisole in seven steps.
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Affiliation(s)
- H M T Bandara Herath
- National Center for Natural Products Research, Research Institute of Pharmaceutical Sciences, School of Pharmacy, The University of Mississippi, MS, 38677, USA
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