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Nair AS, Woodford J, Loughland J, Andrew D, Piera K, Amante F, William T, Grigg MJ, McCarthy JS, Anstey NM, Boyle MJ, Barber BE. Osteoprotegerin (OPG) and its ligands RANKL and TRAIL in falciparum, vivax and knowlesi malaria: correlations with disease severity, and B cell production of OPG. MEDRXIV : THE PREPRINT SERVER FOR HEALTH SCIENCES 2024:2024.07.22.24310838. [PMID: 39108527 PMCID: PMC11302609 DOI: 10.1101/2024.07.22.24310838] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 08/13/2024]
Abstract
Osteoprotegerin (OPG) is a soluble decoy receptor for receptor activator of NF-ƙB ligand (RANKL) and TNF-related apoptosis-inducing ligand (TRAIL), and is increasingly recognised as a marker of poor prognosis in a number of diseases. Here we demonstrate that in Malaysian adults with falciparum and vivax malaria, OPG is increased, and its ligands TRAIL and RANKL decreased, in proportion to disease severity. In volunteers experimentally infected with P. falciparum and P. vivax, RANKL was suppressed, while TRAIL was unexpectedly increased, suggesting binding of OPG to RANKL prior to TRAIL. We also demonstrate that P. falciparum stimulates B cells to produce OPG in vitro, and that B cell OPG production is increased ex vivo in patients with falciparum, vivax and knowlesi malaria. Our findings provide further evidence of the importance of the OPG/RANKL/TRAIL pathway in pathogenesis of diseases involving systemic inflammation, and may have implications for adjunctive therapies. Further evaluation of the role of B cell production of OPG in host responses to malaria and other inflammatory diseases is warranted.
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Affiliation(s)
| | - John Woodford
- QIMR Berghofer Medical Research Institute, Brisbane, Australia
- Laboratory of Malaria Immunology and Vaccinology, National Institute of Allergy and Infectious Diseases, Bethesda, United States
| | - Jessica Loughland
- QIMR Berghofer Medical Research Institute, Brisbane, Australia
- Burnet Institute, Melbourne, Australia
| | - Dean Andrew
- QIMR Berghofer Medical Research Institute, Brisbane, Australia
| | - Kim Piera
- Menzies School of Health Research, Darwin, Australia
| | - Fiona Amante
- QIMR Berghofer Medical Research Institute, Brisbane, Australia
| | | | | | - James S McCarthy
- QIMR Berghofer Medical Research Institute, Brisbane, Australia
- Peter Doherty Institute for Infection and Immunity, Melbourne, Australia
| | | | - Michelle J Boyle
- QIMR Berghofer Medical Research Institute, Brisbane, Australia
- Burnet Institute, Melbourne, Australia
| | - Bridget E Barber
- QIMR Berghofer Medical Research Institute, Brisbane, Australia
- Menzies School of Health Research, Darwin, Australia
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Nandal R, Kumar D, Aggarwal N, Kumar V, Narasimhan B, Marwaha RK, Sharma PC, Kumar S, Bansal N, Chopra H, Deep A. Recent advances, challenges and updates on the development of therapeutics for malaria. EXCLI JOURNAL 2024; 23:672-713. [PMID: 38887396 PMCID: PMC11180964 DOI: 10.17179/excli2023-6856] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Figures] [Subscribe] [Scholar Register] [Received: 12/02/2023] [Accepted: 04/03/2024] [Indexed: 06/20/2024]
Abstract
Malaria has developed as a serious worldwide health issue as a result of the introduction of resistant Plasmodium species strains. Because of the common chemo resistance to most of the existing drugs on the market, it poses a severe health problem and significant obstacles in drug research. Malaria treatment has evolved during the last two decades in response to Plasmodium falciparum drug sensitivity and a return of the disease in tropical areas. Plasmodium falciparum is now highly resistant to the majority of antimalarial drugs. The parasite resistance drew focus to developing novel antimalarials to combat parasite resistance. The requirement for many novel antimalarial drugs in the future year necessitates adopting various drug development methodologies. Different innovative strategies for discovering antimalarial drugs are now being examined here. This review is primarily concerned with the description of newly synthesized antimalarial compounds, i.e. Tafenoquine, Cipargamin, Ferroquine, Artefenomel, DSM265, MMV390048 designed to improve the activity of pure antimalarial enantiomers. In this review, we selected the representative malarial drugs in clinical trials, classified them with detailed targets according to their action, discussed the relationship within the human trials, and generated a summative discussion with prospective expectations.
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Affiliation(s)
- Rimmy Nandal
- Shri Baba MastNath Institute of Pharmaceutical Sciences and Research, Baba Mast Nath University, Asthal Bohar, Rohtak-124001, Haryana, India
| | - Davinder Kumar
- College of Pharmacy, PGIMS University of Health Sciences, Rohtak-124001, Haryana, India
| | - Navidha Aggarwal
- MM College of Pharmacy, Maharishi Markandeshwar (Deemed to be University), Mullana, Ambala 133207, India
| | - Virender Kumar
- College of Pharmacy, PGIMS University of Health Sciences, Rohtak-124001, Haryana, India
| | | | - Rakesh Kumar Marwaha
- Department of Pharmaceutical Sciences, Maharishi Dayanand University, Rohtak 124001 Haryana, India
| | - Prabodh Chander Sharma
- Department of Pharmaceutical Chemistry, School of Pharmaceutical Sciences, Delhi Pharmaceutical Sciences and Research University, New Delhi 110017, India
| | - Surender Kumar
- Department of Chemistry, Chaudhary Bansi Lal University, Bhiwani-127021, India
| | - Nitin Bansal
- Department of Pharmaceutical Sciences, Chaudhary Bansi Lal University, Bhiwani-127021, Haryana, India
| | - Hitesh Chopra
- Department of Biosciences, Saveetha School of Engineering, Saveetha Institute of Medical and Technical Sciences, Chennai - 602105, Tamil Nadu, India
| | - Aakash Deep
- Department of Pharmaceutical Sciences, Chaudhary Bansi Lal University, Bhiwani-127021, Haryana, India
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Schäfer TM, Pessanha de Carvalho L, Inoue J, Kreidenweiss A, Held J. The problem of antimalarial resistance and its implications for drug discovery. Expert Opin Drug Discov 2024; 19:209-224. [PMID: 38108082 DOI: 10.1080/17460441.2023.2284820] [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: 07/28/2023] [Accepted: 11/14/2023] [Indexed: 12/19/2023]
Abstract
INTRODUCTION Malaria remains a devastating infectious disease with hundreds of thousands of casualties each year. Antimalarial drug resistance has been a threat to malaria control and elimination for many decades and is still of concern today. Despite the continued effectiveness of current first-line treatments, namely artemisinin-based combination therapies, the emergence of drug-resistant parasites in Southeast Asia and even more alarmingly the occurrence of resistance mutations in Africa is of great concern and requires immediate attention. AREAS COVERED A comprehensive overview of the mechanisms underlying the acquisition of drug resistance in Plasmodium falciparum is given. Understanding these processes provides valuable insights that can be harnessed for the development and selection of novel antimalarials with reduced resistance potential. Additionally, strategies to mitigate resistance to antimalarial compounds on the short term by using approved drugs are discussed. EXPERT OPINION While employing strategies that utilize already approved drugs may offer a prompt and cost-effective approach to counter antimalarial drug resistance, it is crucial to recognize that only continuous efforts into the development of novel antimalarial drugs can ensure the successful treatment of malaria in the future. Incorporating resistance propensity assessment during this developmental process will increase the likelihood of effective and enduring malaria treatments.
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Affiliation(s)
| | | | - Juliana Inoue
- Institute of Tropical Medicine, University of Tübingen, Tübingen, Germany
| | - Andrea Kreidenweiss
- Institute of Tropical Medicine, University of Tübingen, Tübingen, Germany
- Centre de Recherches Médicales de Lambaréné, Lambaréné, Gabon
- German Center for Infection Research (DZIF), Tübingen, Germany
| | - Jana Held
- Institute of Tropical Medicine, University of Tübingen, Tübingen, Germany
- Centre de Recherches Médicales de Lambaréné, Lambaréné, Gabon
- German Center for Infection Research (DZIF), Tübingen, Germany
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Kratz JC, Banerjee S. Gene expression tradeoffs determine bacterial survival and adaptation to antibiotic stress. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.01.20.576495. [PMID: 38328084 PMCID: PMC10849509 DOI: 10.1101/2024.01.20.576495] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/09/2024]
Abstract
To optimize their fitness, cells face the crucial task of efficiently responding to various stresses. This necessitates striking a balance between conserving resources for survival and allocating resources for growth and division. The fundamental principles governing these tradeoffs is an outstanding challenge in the physics of living systems. In this study, we introduce a coarse-grained theoretical framework for bacterial physiology that establishes a connection between the physiological state of cells and their survival outcomes in dynamic environments, particularly in the context of antibiotic exposure. Predicting bacterial survival responses to varying antibiotic doses proves challenging due to the profound influence of the physiological state on critical parameters, such as the Minimum Inhibitory Concentration (MIC) and killing rates, even within an isogenic cell population. Our proposed theoretical model bridges the gap by linking extracellular antibiotic concentration and nutrient quality to intracellular damage accumulation and gene expression. This framework allows us to predict and explain the control of cellular growth rate, death rate, MIC and survival fraction in a wide range of time-varying environments. Surprisingly, our model reveals that cell death is rarely due to antibiotic levels being above the maximum physiological limit, but instead survival is limited by the inability to alter gene expression sufficiently quickly to transition to a less susceptible physiological state. Moreover, bacteria tend to overexpress stress response genes at the expense of reduced growth, conferring greater protection against further antibiotic exposure. This strategy is in contrast to those employed in different nutrient environments, in which bacteria allocate resources to maximize growth rate. This highlights an important tradeoff between the cellular capacity for growth and the ability to survive antibiotic exposure.
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Affiliation(s)
- Josiah C. Kratz
- Computational Biology Department, Carnegie Mellon University, Pittsburgh, PA 15213, USA
- Department of Biological Sciences, Carnegie Mellon University, Pittsburgh, PA 15213, USA
| | - Shiladitya Banerjee
- Department of Physics, Carnegie Mellon University, Pittsburgh, PA 15213, USA
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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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Pontikos MA, Leija C, Zhao Z, Wang X, Kilgore J, Tornesi B, Adenmatten N, Phillips MA, Williams NS. Development of a biomarker to monitor target engagement after treatment with dihydroorotate dehydrogenase inhibitors. Biochem Pharmacol 2022; 204:115237. [PMID: 36055381 PMCID: PMC9547971 DOI: 10.1016/j.bcp.2022.115237] [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: 07/01/2022] [Revised: 08/24/2022] [Accepted: 08/25/2022] [Indexed: 11/22/2022]
Abstract
Dihydroorotate dehydrogenase (DHODH) catalyzes a key step in pyrimidine biosynthesis and has recently been validated as a therapeutic target for malaria through clinical studies on the triazolopyrimidine-based Plasmodium DHODH inhibitor DSM265. Selective toxicity towards Plasmodium species could be achieved because malaria parasites lack pyrimidine salvage pathways, and DSM265 selectively inhibits Plasmodium DHODH over the human enzyme. However, while DSM265 does not inhibit human DHODH, it inhibits DHODH from several preclinical species, including mice, suggesting that toxicity could result from on-target DHODH inhibition in those species. We describe here the use of dihydroorotate (DHO) as a biomarker of DHODH inhibition. Treatment of mammalian cells with DSM265 or the mammalian DHODH inhibitor teriflunomide led to increases in DHO where the extent of biomarker buildup correlated with both dose and inhibitor potency on DHODH. Treatment of mice with leflunomide (teriflunomide prodrug) caused a large dose-dependent buildup of DHO in blood (up to 16-fold) and urine (up to 5,400-fold) that was not observed for mice treated with DSM265. Unbound plasma teriflunomide levels reached 20-85-fold above the mouse DHODH IC50, while free DSM265 levels were only 1.6-4.2-fold above, barely achieving ∼ IC90 concentrations, suggesting that unbound DSM265 plasma levels are not sufficient to block the pathway in vivo. Thus, any toxicity associated with DSM265 treatment in mice is likely caused by off-target mechanisms. The identification of a robust biomarker for mammalian DHODH inhibition represents an important advance to generally monitor for on-target effects in preclinical and clinical applications of DHODH inhibitors used to treat human disease.
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Affiliation(s)
- Michael A Pontikos
- Department of Biochemistry, University of Texas Southwestern Medical Center at Dallas, 5323 Harry Hines Blvd, Dallas, TX 75390-9135, United States
| | - Christopher Leija
- Department of Biochemistry, University of Texas Southwestern Medical Center at Dallas, 5323 Harry Hines Blvd, Dallas, TX 75390-9135, United States
| | - Zhiyu Zhao
- Children's Medical Center Research Institute, University of Texas Southwestern Medical Center at Dallas, 5323 Harry Hines Blvd, Dallas, TX 75390, United States
| | - Xiaoyu Wang
- Department of Biochemistry, University of Texas Southwestern Medical Center at Dallas, 5323 Harry Hines Blvd, Dallas, TX 75390-9135, United States
| | - Jessica Kilgore
- Department of Biochemistry, University of Texas Southwestern Medical Center at Dallas, 5323 Harry Hines Blvd, Dallas, TX 75390-9135, United States
| | - Belen Tornesi
- Medicines for Malaria Venture, 1215 Geneva, Switzerland
| | | | - Margaret A Phillips
- Department of Biochemistry, University of Texas Southwestern Medical Center at Dallas, 5323 Harry Hines Blvd, Dallas, TX 75390-9135, United States.
| | - Noelle S Williams
- Department of Biochemistry, University of Texas Southwestern Medical Center at Dallas, 5323 Harry Hines Blvd, Dallas, TX 75390-9135, United States.
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Janin YL. On drug discovery against infectious diseases and academic medicinal chemistry contributions. Beilstein J Org Chem 2022; 18:1355-1378. [PMID: 36247982 PMCID: PMC9531561 DOI: 10.3762/bjoc.18.141] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2022] [Accepted: 09/21/2022] [Indexed: 11/23/2022] Open
Abstract
This perspective is an attempt to document the problems that medicinal chemists are facing in drug discovery. It is also trying to identify relevant/possible, research areas in which academics can have an impact and should thus be the subject of grant calls. Accordingly, it describes how hit discovery happens, how compounds to be screened are selected from available chemicals and the possible reasons for the recurrent paucity of useful/exploitable results reported. This is followed by the successful hit to lead stories leading to recent and original antibacterials which are, or about to be, used in human medicine. Then, illustrated considerations and suggestions are made on the possible inputs of academic medicinal chemists. This starts with the observation that discovering a "good" hit in the course of a screening campaign still rely on a lot of luck - which is within the reach of academics -, that the hit to lead process requires a lot of chemistry and that if public-private partnerships can be important throughout these stages, they are absolute requirements for clinical trials. Concerning suggestions to improve the current hit success rate, one academic input in organic chemistry would be to identify new and pertinent chemical space, design synthetic accesses to reach these and prepare the corresponding chemical libraries. Concerning hit to lead programs on a given target, if no new hits are available, previously reported leads along with new structural data can be pertinent starting points to design, prepare and assay original analogues. In conclusion, this text is an actual plea illustrating that, in many countries, academic research in medicinal chemistry should be more funded, especially in the therapeutic area neglected by the industry. At the least, such funds would provide the intensive to secure series of hopefully relevant chemical entities which appears to often lack when considering the results of academic as well as industrial screening campaigns.
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Affiliation(s)
- Yves L Janin
- Structure et Instabilité des Génomes (StrInG), Muséum National d'Histoire Naturelle, INSERM, CNRS, Alliance Sorbonne Université, 75005 Paris, France
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8
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Marquart L, Webb L, O'Rourke P, Gatton ML, Hsiang MS, Kalnoky M, Jang IK, Ntuku H, Mumbengegwi DR, Domingo GJ, McCarthy JS, Britton S. The in-vivo dynamics of Plasmodium falciparum HRP2: implications for the use of rapid diagnostic tests in malaria elimination. Malar J 2022; 21:233. [PMID: 35922803 PMCID: PMC9351188 DOI: 10.1186/s12936-022-04245-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2021] [Accepted: 07/13/2022] [Indexed: 11/24/2022] Open
Abstract
Background Rapid diagnostic tests (RDTs) that rely on the detection of Plasmodium falciparum histidine-rich protein 2 (PfHRP2) have become key tools for diagnosing P. falciparum infection. The utility of RDTs can be limited by PfHRP2 persistence, however it can be a potential benefit in low transmission settings where detection of persistent PfHRP2 using newer ultra-sensitive PfHRP2 based RDTs can serve as a surveillance tool to identify recent exposure. Better understanding of the dynamics of PfHRP2 over the course of a malaria infection can inform optimal use of RDTs. Methods A previously published mathematical model was refined to mimic the production and decay of PfHRP2 during a malaria infection. Data from 15 individuals from volunteer infection studies were used to update the original model and estimate key model parameters. The refined model was applied to a cohort of patients from Namibia who received treatment for clinical malaria infection for whom longitudinal PfHRP2 concentrations were measured. Results The refinement of the PfHRP2 dynamic model indicated that in malaria naïve hosts, P. falciparum parasites of the 3D7 strain produce 33.6 × 10−15 g (95% CI 25.0–42.1 × 10−15 g) of PfHRP2 in vivo per parasite replication cycle, with an elimination half-life of 1.67 days (95% CI 1.11–3.40 days). The refined model included these updated parameters and incorporated individualized body fluid volume calculations, which improved predictive accuracy when compared to the original model. The performance of the model in predicting clearance of PfHRP2 post treatment in clinical samples from six adults with P. falciparum infection in Namibia improved when using a longer elimination half-life of 4.5 days, with 14% to 67% of observations for each individual within the predicted range. Conclusions The updated mathematical model can predict the growth and clearance of PfHRP2 during the production and decay of a mono-infection with P. falciparum, increasing the understanding of PfHRP2 antigen dynamics. This model can guide the optimal use of PfHRP2-based RDTs for reliable diagnosis of P. falciparum infection and re-infection in endemic settings, but also for malaria surveillance and elimination programmes in low transmission areas. Supplementary Information The online version contains supplementary material available at 10.1186/s12936-022-04245-z.
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Affiliation(s)
- Louise Marquart
- QIMR Berghofer Medical Research Institute, Brisbane, QLD, Australia. .,University of Queensland, Brisbane, QLD, Australia.
| | - Lachlan Webb
- QIMR Berghofer Medical Research Institute, Brisbane, QLD, Australia
| | - Peter O'Rourke
- QIMR Berghofer Medical Research Institute, Brisbane, QLD, Australia
| | | | - Michelle S Hsiang
- Department of Pediatrics, University of Texas, Southwestern, Dallas, TX, USA.,Malaria Elimination Initiative, Institute for Global Health Services, University of California, San Francisco, CA, USA.,Department of Pediatrics, University of California, San Francisco, CA, USA
| | | | | | - Henry Ntuku
- Malaria Elimination Initiative, Institute for Global Health Services, University of California, San Francisco, CA, USA
| | | | | | - James S McCarthy
- QIMR Berghofer Medical Research Institute, Brisbane, QLD, Australia.,University of Queensland, Brisbane, QLD, Australia
| | - Sumudu Britton
- QIMR Berghofer Medical Research Institute, Brisbane, QLD, Australia.,University of Queensland, Brisbane, QLD, Australia
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9
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Barber BE, Fernandez M, Patel HB, Barcelo C, Woolley SD, Patel H, Llewellyn S, Abd-Rahman AN, Sharma S, Jain M, Ghoghari A, Di Resta I, Fuchs A, Deni I, Yeo T, Mok S, Fidock DA, Chalon S, Möhrle JJ, Parmar D, McCarthy JS, Kansagra K. Safety, pharmacokinetics, and antimalarial activity of the novel triaminopyrimidine ZY-19489: a first-in-human, randomised, placebo-controlled, double-blind, single ascending dose study, pilot food-effect study, and volunteer infection study. THE LANCET INFECTIOUS DISEASES 2022; 22:879-890. [DOI: 10.1016/s1473-3099(21)00679-4] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/13/2021] [Revised: 08/30/2021] [Accepted: 10/13/2021] [Indexed: 01/04/2023]
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10
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Moehrle JJ. Development of New Strategies for Malaria Chemoprophylaxis: From Monoclonal Antibodies to Long-Acting Injectable Drugs. Trop Med Infect Dis 2022; 7:tropicalmed7040058. [PMID: 35448833 PMCID: PMC9024890 DOI: 10.3390/tropicalmed7040058] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2022] [Revised: 03/18/2022] [Accepted: 03/22/2022] [Indexed: 02/04/2023] Open
Abstract
Drug discovery for malaria has traditionally focused on orally available drugs that kill the abundant, parasitic blood stage. Recently, there has also been an interest in injectable medicines, in the form of monoclonal antibodies (mAbs) with long-lasting plasma half-lives or long-lasting depot formulations of small molecules. These could act as prophylactic drugs, targeting the sporozoites and other earlier parasitic stages in the liver, when the parasites are less numerous, or as another intervention strategy targeting the formation of infectious gametocytes. Generally speaking, the development of mAbs is less risky (costly) than small-molecule drugs, and they have an excellent safety profile with few or no off-target effects. Therefore, populations who are the most vulnerable to malaria, i.e., pregnant women and young children would have access to such new treatments much faster than is presently the case for new antimalarials. An analysis of mAbs that were successfully developed for oncology illustrates some of the feasibility aspects, and their potential as affordable drugs in low- and middle-income countries.
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Affiliation(s)
- Joerg J Moehrle
- Integrated Sciences, R&D, Medicines for Malaria Venture, Route de Pré Bois 20, CH-1215 Geneva 15, Switzerland
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11
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Engbers AGJ, Flint RB, Voeller S, Reiss I, Liem KD, Alffenaar JWC, Tibboel D, Simons S, Knibbe CAJ, Brüggemann RJ. Optimisation of fluconazole therapy for the treatment of invasive candidiasis in preterm infants. Arch Dis Child 2022; 107:400-406. [PMID: 35074829 DOI: 10.1136/archdischild-2021-322560] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/01/2021] [Accepted: 12/19/2021] [Indexed: 11/04/2022]
Abstract
INTRODUCTION Fluconazole is an important antifungal in the prevention and treatment of invasive Candida infections in neonates, even though its use in preterm infants is still off-label. Here, we performed a population pharmacokinetic study on fluconazole in preterm neonates in order to optimise dosing through the identified predictive patient characteristics. METHODS Fluconazole concentrations obtained from preterm infants from two studies were pooled and analysed using NONMEM V.7.3. The developed model was used to evaluate current dosing practice. A therapeutic dosing strategy aiming to reach a minimum target exposure of 400 and 200 mg×hour/L per 24 hours for fluconazole-susceptible C. albicans meningitis and other systemic infections, respectively, was developed. RESULTS In 41 preterm neonates with median (range) gestational age 25.3 (24.0-35.1) weeks and median postnatal age (PNA) at treatment initiation 1.4 (0.2-32.5) days, 146 plasma samples were collected. A one-compartment model described the data best, with an estimated clearance of 0.0147 L/hour for a typical infant of 0.87 kg with a serum creatinine concentration of 60 µmol/L and volume of distribution of 0.844 L. Clearance was found to increase with 16% per 100 g increase in actual body weight, and to decrease with 12% per 10 µmol/L increase in creatinine concentration once PNA was above 1 week. Dose adjustments based on serum creatinine and daily dosing are required for therapeutic target attainment. CONCLUSION In preterm neonates, fluconazole clearance is best predicted by actual body weight and serum creatinine concentration. Therefore, fluconazole dosing should not only be based on body weight but also on creatinine concentration to achieve optimal exposure in all infants. ETHICS STATEMENT The Erasmus MC ethics review board approved the protocol of the DINO Study (MEC-2014-067) and the Radboud UMC ethics review board waived the need for informed consent for cohort 2 (CMO-2021-8302). Written informed consent from parents/legal guardians was obtained prior to study initiation.
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Affiliation(s)
- Aline G J Engbers
- Division of Systems Biomedicine and Pharmacology, LACDR, Leiden, The Netherlands.,Department of Paediatrics, Division of Neonatology, Erasmus MC Sophia Children's Hospital, Rotterdam, The Netherlands
| | - Robert B Flint
- Department of Paediatrics, Division of Neonatology, Erasmus MC Sophia Children's Hospital, Rotterdam, The Netherlands.,Department of Hospital Pharmacy, Erasmus Medical Center, Rotterdam, The Netherlands
| | - Swantje Voeller
- Division of Systems Biomedicine and Pharmacology, LACDR, Leiden, The Netherlands.,Division of Biotherapeutics, LACDR, Leiden, The Netherlands
| | - Irwin Reiss
- Department of Paediatrics, Division of Neonatology, Erasmus MC Sophia Children's Hospital, Rotterdam, The Netherlands
| | - Kian D Liem
- Department of Neonatology, Radboudumc, Nijmegen, The Netherlands
| | - Jan-Willem C Alffenaar
- Department of Clinical Pharmacy and Pharmacology, University Medical Centre Groningen, Groningen, The Netherlands
| | - Dick Tibboel
- Department of Paediatrics, Division of Neonatology, Erasmus MC Sophia Children's Hospital, Rotterdam, The Netherlands
| | - Sinno Simons
- Department of Paediatrics, Division of Neonatology, Erasmus MC Sophia Children's Hospital, Rotterdam, The Netherlands
| | - Catherijne A J Knibbe
- Division of Systems Biomedicine and Pharmacology, LACDR, Leiden, The Netherlands .,Clinical Pharmacy, Saint Anthony Hospital, Nieuwegein, The Netherlands
| | - Roger J Brüggemann
- Department of Pharmacy, Radboudumc, Nijmegen, The Netherlands.,Radboudumc Center for Infectious Diseases and Center of Expertise in Mycology Radboudumc/CWZ, Radboud University Medical Center, Nijmegen, The Netherlands
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12
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Woolley SD, Marquart L, Woodford J, Chalon S, Moehrle JJ, McCarthy JS, Barber BE. Haematological response in experimental human Plasmodium falciparum and Plasmodium vivax malaria. Malar J 2021; 20:470. [PMID: 34930260 PMCID: PMC8685492 DOI: 10.1186/s12936-021-04003-7] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2021] [Accepted: 12/01/2021] [Indexed: 11/25/2022] Open
Abstract
Background Malaria-associated anaemia, arising from symptomatic, asymptomatic and submicroscopic infections, is a significant cause of morbidity worldwide. Induced blood stage malaria volunteer infection studies (IBSM-VIS) provide a unique opportunity to evaluate the haematological response to early Plasmodium falciparum and Plasmodium vivax infection. Methods This study was an analysis of the haemoglobin, red cell counts, and parasitaemia data from 315 participants enrolled in IBSM-VIS between 2012 and 2019, including 269 participants inoculated with the 3D7 strain of P. falciparum (Pf3D7), 15 with an artemisinin-resistant P. falciparum strain (PfK13) and 46 with P. vivax. Factors associated with the fractional fall in haemoglobin (Hb-FF) were evaluated, and the malaria-attributable erythrocyte loss after accounting for phlebotomy-related losses was estimated. The relative contribution of parasitized erythrocytes to the malaria-attributable erythrocyte loss was also estimated. Results The median peak parasitaemia prior to treatment was 10,277 parasites/ml (IQR 3566–27,815), 71,427 parasites/ml [IQR 33,236–180,213], and 34,840 parasites/ml (IQR 13,302–77,064) in participants inoculated with Pf3D7, PfK13, and P. vivax, respectively. The median Hb-FF was 10.3% (IQR 7.8–13.3), 14.8% (IQR 11.8–15.9) and 11.7% (IQR 8.9–14.5) in those inoculated with Pf3D7, PfK13 and P. vivax, respectively, with the haemoglobin nadir occurring a median 12 (IQR 5–21), 15 (IQR 7–22), and 8 (IQR 7–15) days following inoculation. In participants inoculated with P. falciparum, recrudescence was associated with a greater Hb-FF, while in those with P. vivax, the Hb-FF was associated with a higher pre-treatment parasitaemia and later day of anti-malarial treatment. After accounting for phlebotomy-related blood losses, the estimated Hb-FF was 4.1% (IQR 3.1–5.3), 7.2% (IQR 5.8–7.8), and 4.9% (IQR 3.7–6.1) in participants inoculated with Pf3D7, PfK13, and P. vivax, respectively. Parasitized erythrocytes were estimated to account for 0.015% (IQR 0.006–0.06), 0.128% (IQR 0.068–0.616) and 0.022% (IQR 0.008–0.082) of the malaria-attributable erythrocyte loss in participants inoculated with Pf3D7, PfK13, and P. vivax, respectively. Conclusion Early experimental P. falciparum and P. vivax infection resulted in a small but significant fall in haemoglobin despite parasitaemia only just at the level of microscopic detection. Loss of parasitized erythrocytes accounted for < 0.2% of the total malaria-attributable haemoglobin loss. Supplementary Information The online version contains supplementary material available at 10.1186/s12936-021-04003-7.
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13
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McCarthy JS, Yalkinoglu Ö, Odedra A, Webster R, Oeuvray C, Tappert A, Bezuidenhout D, Giddins MJ, Dhingra SK, Fidock DA, Marquart L, Webb L, Yin X, Khandelwal A, Bagchus WM. Safety, pharmacokinetics, and antimalarial activity of the novel plasmodium eukaryotic translation elongation factor 2 inhibitor M5717: a first-in-human, randomised, placebo-controlled, double-blind, single ascending dose study and volunteer infection study. THE LANCET. INFECTIOUS DISEASES 2021; 21:1713-1724. [PMID: 34715032 PMCID: PMC8612936 DOI: 10.1016/s1473-3099(21)00252-8] [Citation(s) in RCA: 35] [Impact Index Per Article: 11.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/24/2020] [Revised: 03/02/2021] [Accepted: 04/13/2021] [Indexed: 01/28/2023]
Abstract
BACKGROUND M5717 is the first plasmodium translation elongation factor 2 inhibitor to reach clinical development as an antimalarial. We aimed to characterise the safety, pharmacokinetics, and antimalarial activity of M5717 in healthy volunteers. METHODS This first-in-human study was a two-part, single-centre clinical trial done in Brisbane, QLD, Australia. Part one was a double-blind, randomised, placebo-controlled, single ascending dose study in which participants were enrolled into one of nine dose cohorts (50, 100, 200, 400, 600, 1000, 1250, 1800, or 2100 mg) and randomly assigned (3:1) to M5717 or placebo. A sentinel dosing strategy was used for each dose cohort whereby two participants (one assigned to M5717 and one assigned to placebo) were initially randomised and dosed. Randomisation schedules were generated electronically by independent, unblinded statisticians. Part two was an open-label, non-randomised volunteer infection study using the Plasmodium falciparum induced blood-stage malaria model in which participants were enrolled into three dose cohorts. Healthy men and women of non-childbearing potential aged 18-55 years were eligible for inclusion; individuals in the volunteer infection study were required to be malaria naive. Safety and tolerability (primary outcome of the single ascending dose study and secondary outcome of the volunteer infection study) were assessed by frequency and severity of adverse events. The pharmacokinetic profile of M5717 was also characterised (primary outcome of the volunteer infection study and secondary outcome of the single ascending dose study). Parasite clearance kinetics (primary outcome of the volunteer infection study) were assessed by the parasite reduction ratio and the corresponding parasite clearance half-life; the incidence of recrudescence up to day 28 was determined (secondary outcome of the volunteer infection study). Recrudescent parasites were tested for genetic mutations (exploratory outcome). The trial is registered with ClinicalTrials.gov (NCT03261401). FINDINGS Between Aug 28, 2017, and June 14, 2019, 221 individuals were assessed for eligibility, of whom 66 men were enrolled in the single ascending dose study (eight per cohort for 50-1800 mg cohorts, randomised three M5717 to one placebo, and two in the 2100 mg cohort, randomised one M5717 to one placebo) and 22 men were enrolled in the volunteer infection study (six in the 150 mg cohort and eight each in the 400 mg and 800 mg cohorts). No adverse event was serious; all M5717-related adverse events were mild or moderate in severity and transient, with increased frequency observed at doses above 1250 mg. In the single ascending dose study, treatment-related adverse events occurred in three of 17 individuals in the placebo group; no individual in the 50 mg, 100 mg, or 200 mg groups; one of six individuals in each of the 400 mg, 1000 mg, and 1250 mg groups; two of six individuals in the 600 mg group; and in all individuals in the 1800 mg and 2100 mg groups. In the volunteer infection study, M5717-related adverse events occurred in no participants in the 150 mg or 800 mg groups and in one of eight participants in the 400 mg group. Transient oral hypoesthesia (in three participants) and blurred vision (in four participants) were observed in the 1800 mg or 2100 mg groups and constituted an unknown risk; thus, further dosing was suspended after dosing of the two sentinel individuals in the 2100 mg cohort. Maximum blood concentrations occurred 1-7 h after dosing, and a long half-life was observed (146-193 h at doses ≥200 mg). Parasite clearance occurred in all participants and was biphasic, characterised by initial slow clearance lasting 35-55 h (half-life 231·1 h [95% CI 40·9 to not reached] for 150 mg, 60·4 h [38·6 to 138·6] for 400 mg, and 24·7 h [20·4 to 31·3] for 800 mg), followed by rapid clearance (half-life 3·5 h [3·1 to 4·0] for 150 mg, 3·9 h [3·3 to 4·8] for 400 mg, and 5·5 h [4·8 to 6·4] for 800 mg). Recrudescence occurred in three (50%) of six individuals dosed with 150 mg and two (25%) of eight individuals dosed with 400 mg. Genetic mutations associated with resistance were detected in four cases of parasite recrudescence (two individuals dosed with 150 mg and two dosed with 400 mg). INTERPRETATION The safety, pharmacokinetics, and antimalarial activity of M5717 support its development as a component of a single-dose antimalarial combination therapy or for malaria prophylaxis. FUNDING Wellcome Trust and the healthcare business of Merck KGaA, Darmstadt, Germany.
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Affiliation(s)
- James S McCarthy
- QIMR Berghofer Medical Research Institute, Brisbane, QLD, Australia; The Peter Doherty Institute for Infection and Immunity, The University of Melbourne and the Royal Melbourne Hospital, Melbourne, VIC, Australia
| | | | - Anand Odedra
- QIMR Berghofer Medical Research Institute, Brisbane, QLD, Australia; Liverpool School of Tropical Medicine, Liverpool, UK
| | - Rebecca Webster
- QIMR Berghofer Medical Research Institute, Brisbane, QLD, Australia
| | - Claude Oeuvray
- The Global Health Institute of Merck (an affiliate of Merck KGaA), Eysin, Switzerland
| | - Aliona Tappert
- the healthcare business of Merck KGaA, Darmstadt, Germany
| | | | - Marla J Giddins
- Department of Microbiology and Immunology, Columbia University Irving Medical Center, New York, NY, USA
| | - Satish K Dhingra
- Department of Microbiology and Immunology, Columbia University Irving Medical Center, New York, NY, USA
| | - David A Fidock
- Department of Microbiology and Immunology, Columbia University Irving Medical Center, New York, NY, USA; Division of Infectious Diseases, Department of Medicine, Columbia University Irving Medical Center, New York, NY, USA
| | - Louise Marquart
- QIMR Berghofer Medical Research Institute, Brisbane, QLD, Australia
| | - Lachlan Webb
- QIMR Berghofer Medical Research Institute, Brisbane, QLD, Australia
| | - Xiaoyan Yin
- Global Statistics for NDD, Immunology, Endocrinology, Fertility & Others, EMD Serono, Billerica, MA, USA
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14
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Antimalarial drug candidates in phase I and II drug development: a scoping review. Antimicrob Agents Chemother 2021; 66:e0165921. [PMID: 34843390 PMCID: PMC8846400 DOI: 10.1128/aac.01659-21] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The emergence and spread of parasite resistance to currently available antimalarials has highlighted the importance of developing novel antimalarials. This scoping review provides an overview of antimalarial drug candidates undergoing phase I and II studies between 1 January 2016 and 28 April 2021. PubMed, Web of Science, Embase, clinical trial registries, and reference lists were searched for relevant studies. Information regarding antimalarial compound details, clinical trial characteristics, study population, and drug pharmacokinetics and pharmacodynamics (PK-PD) were extracted. A total of 50 studies were included, of which 24 had published their results and 26 were unpublished. New antimalarial compounds were evaluated as monotherapy (28 studies, 14 drug candidates) and combination therapy (9 studies, 10 candidates). Fourteen active compounds were identified in the current antimalarial drug development pipeline together with 11 compounds that are inactive, 6 due to insufficient efficacy. PK-PD data were available from 24 studies published as open-access articles. Four unpublished studies have made their results publicly available on clinical trial registries. The terminal elimination half-life of new antimalarial compounds ranged from 14.7 to 483 h. The log10 parasite reduction ratio over 48 h and parasite clearance half-life for Plasmodium falciparum following a single-dose monotherapy were 1.55 to 4.1 and 3.4 to 9.4 h, respectively. The antimalarial drug development landscape has seen a number of novel compounds, with promising PK-PD properties, evaluated in phase I and II studies over the past 5 years. Timely public disclosure of PK-PD data is crucial for informative decision-making and drug development strategy.
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15
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Webster R, Sekuloski S, Odedra A, Woolley S, Jennings H, Amante F, Trenholme KR, Healer J, Cowman AF, Eriksson EM, Sathe P, Penington J, Blanch AJ, Dixon MWA, Tilley L, Duffy MF, Craig A, Storm J, Chan JA, Evans K, Papenfuss AT, Schofield L, Griffin P, Barber BE, Andrew D, Boyle MJ, de Labastida Rivera F, Engwerda C, McCarthy JS. Safety, infectivity and immunogenicity of a genetically attenuated blood-stage malaria vaccine. BMC Med 2021; 19:293. [PMID: 34802442 PMCID: PMC8606250 DOI: 10.1186/s12916-021-02150-x] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/06/2021] [Accepted: 09/30/2021] [Indexed: 01/24/2023] Open
Abstract
BACKGROUND There is a clear need for novel approaches to malaria vaccine development. We aimed to develop a genetically attenuated blood-stage vaccine and test its safety, infectivity, and immunogenicity in healthy volunteers. Our approach was to target the gene encoding the knob-associated histidine-rich protein (KAHRP), which is responsible for the assembly of knob structures at the infected erythrocyte surface. Knobs are required for correct display of the polymorphic adhesion ligand P. falciparum erythrocyte membrane protein 1 (PfEMP1), a key virulence determinant encoded by a repertoire of var genes. METHODS The gene encoding KAHRP was deleted from P. falciparum 3D7 and a master cell bank was produced in accordance with Good Manufacturing Practice. Eight malaria naïve males were intravenously inoculated (day 0) with 1800 (2 subjects), 1.8 × 105 (2 subjects), or 3 × 106 viable parasites (4 subjects). Parasitemia was measured using qPCR; immunogenicity was determined using standard assays. Parasites were rescued into culture for in vitro analyses (genome sequencing, cytoadhesion assays, scanning electron microscopy, var gene expression). RESULTS None of the subjects who were administered with 1800 or 1.8 × 105 parasites developed parasitemia; 3/4 subjects administered 3× 106 parasites developed significant parasitemia, first detected on days 13, 18, and 22. One of these three subjects developed symptoms of malaria simultaneously with influenza B (day 17; 14,022 parasites/mL); one subject developed mild symptoms on day 28 (19,956 parasites/mL); and one subject remained asymptomatic up to day 35 (5046 parasites/mL). Parasitemia rapidly cleared with artemether/lumefantrine. Parasitemia induced a parasite-specific antibody and cell-mediated immune response. Parasites cultured ex vivo exhibited genotypic and phenotypic properties similar to inoculated parasites, although the var gene expression profile changed during growth in vivo. CONCLUSIONS This study represents the first clinical investigation of a genetically attenuated blood-stage human malaria vaccine. A P. falciparum 3D7 kahrp- strain was tested in vivo and found to be immunogenic but can lead to patent parasitemia at high doses. TRIAL REGISTRATION Australian New Zealand Clinical Trials Registry (number: ACTRN12617000824369 ; date: 06 June 2017).
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Affiliation(s)
- Rebecca Webster
- QIMR Berghofer Medical Research Institute, Brisbane, Australia
| | - Silvana Sekuloski
- QIMR Berghofer Medical Research Institute, Brisbane, Australia.,Current address: PharmOut, 111 Eagle Street, Brisbane, Queensland, 4000, Australia
| | - Anand Odedra
- QIMR Berghofer Medical Research Institute, Brisbane, Australia.,Liverpool School of Tropical Medicine, Liverpool, UK
| | - Stephen Woolley
- QIMR Berghofer Medical Research Institute, Brisbane, Australia.,Liverpool School of Tropical Medicine, Liverpool, UK.,Centre of Defence Pathology, Royal Centre for Defence Medicine, Joint Hospital Group, Birmingham, UK
| | - Helen Jennings
- QIMR Berghofer Medical Research Institute, Brisbane, Australia
| | - Fiona Amante
- QIMR Berghofer Medical Research Institute, Brisbane, Australia
| | - Katharine R Trenholme
- QIMR Berghofer Medical Research Institute, Brisbane, Australia.,The University of Queensland, Brisbane, Australia
| | - Julie Healer
- The Walter and Eliza Hall Institute of Medical Research, Melbourne, Australia
| | - Alan F Cowman
- The Walter and Eliza Hall Institute of Medical Research, Melbourne, Australia.,Department of Microbiology and Immunology, University of Melbourne, Melbourne, Australia
| | - Emily M Eriksson
- The Walter and Eliza Hall Institute of Medical Research, Melbourne, Australia.,Department of Medical Biology, University of Melbourne, Melbourne, Australia
| | - Priyanka Sathe
- Current address: Medicines Development for Global Health Limited, 18 Kavanagh Street, Southbank, Victoria, 3006, Australia
| | - Jocelyn Penington
- The Walter and Eliza Hall Institute of Medical Research, Melbourne, Australia
| | - Adam J Blanch
- Bio21 Molecular Science and Biotechnology Institute, Melbourne, Australia.,Department of Biochemistry and Molecular Biology, University of Melbourne, Melbourne, Australia
| | - Matthew W A Dixon
- Bio21 Molecular Science and Biotechnology Institute, Melbourne, Australia.,Department of Biochemistry and Molecular Biology, University of Melbourne, Melbourne, Australia
| | - Leann Tilley
- Bio21 Molecular Science and Biotechnology Institute, Melbourne, Australia.,Department of Biochemistry and Molecular Biology, University of Melbourne, Melbourne, Australia
| | - Michael F Duffy
- Department of Microbiology and Immunology, University of Melbourne, Melbourne, Australia.,Bio21 Molecular Science and Biotechnology Institute, Melbourne, Australia.,The Peter Doherty Institute for Infection and Immunity, Melbourne, Australia.,Department of Medicine, Royal Melbourne Hospital, Melbourne, Australia
| | - Alister Craig
- Liverpool School of Tropical Medicine, Liverpool, UK
| | - Janet Storm
- Liverpool School of Tropical Medicine, Liverpool, UK
| | | | - Krystal Evans
- The Walter and Eliza Hall Institute of Medical Research, Melbourne, Australia.,Current address: GSK, 436 Johnston Street, Abbotsford, Victoria, 3067, Australia
| | - Anthony T Papenfuss
- The Walter and Eliza Hall Institute of Medical Research, Melbourne, Australia.,Department of Medical Biology, University of Melbourne, Melbourne, Australia
| | - Louis Schofield
- The Walter and Eliza Hall Institute of Medical Research, Melbourne, Australia.,Australian Institute of Tropical Health and Medicine, James Cook University, Cairns, Australia
| | - Paul Griffin
- QIMR Berghofer Medical Research Institute, Brisbane, Australia.,The University of Queensland, Brisbane, Australia.,Department of Medicine and Infectious Diseases, Mater Hospital and Mater Research, Brisbane, Australia
| | | | - Dean Andrew
- QIMR Berghofer Medical Research Institute, Brisbane, Australia
| | | | | | | | - James S McCarthy
- QIMR Berghofer Medical Research Institute, Brisbane, Australia. .,The Peter Doherty Institute for Infection and Immunity, Melbourne, Australia.
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16
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Erhunse N, Sahal D. Protecting future antimalarials from the trap of resistance: Lessons from artemisinin-based combination therapy (ACT) failures. J Pharm Anal 2021; 11:541-554. [PMID: 34765267 PMCID: PMC8572664 DOI: 10.1016/j.jpha.2020.07.005] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2020] [Revised: 07/19/2020] [Accepted: 07/19/2020] [Indexed: 11/01/2022] Open
Abstract
Having faced increased clinical treatment failures with dihydroartemisinin-piperaquine (DHA-PPQ), Cambodia swapped the first line artemisinin-based combination therapy (ACT) from DHA-PPQ to artesunate-mefloquine given that parasites resistant to piperaquine are susceptible to mefloquine. However, triple mutants have now emerged, suggesting that drug rotations may not be adequate to keep resistance at bay. There is, therefore, an urgent need for alternative treatment strategies to tackle resistance and prevent its spread. A proper understanding of all contributors to artemisinin resistance may help us identify novel strategies to keep artemisinins effective until new drugs become available for their replacement. This review highlights the role of the key players in artemisinin resistance, the current strategies to deal with it and suggests ways of protecting future antimalarial drugs from bowing to resistance as their predecessors did.
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Affiliation(s)
- Nekpen Erhunse
- Malaria Drug Discovery Research Group, International Centre for Genetic Engineering and Biotechnology, New Delhi, 110067, India
- Department of Biochemistry, Faculty of Life Sciences, University of Benin, Benin City, Edo-State, Nigeria
| | - Dinkar Sahal
- Malaria Drug Discovery Research Group, International Centre for Genetic Engineering and Biotechnology, New Delhi, 110067, India
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17
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Nordmann T, Borrmann S, Ramharter M. Drug-induced hypersensitivity to artemisinin-based therapies for malaria. Trends Parasitol 2021; 38:136-146. [PMID: 34561157 DOI: 10.1016/j.pt.2021.08.011] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2021] [Revised: 08/27/2021] [Accepted: 08/30/2021] [Indexed: 12/13/2022]
Abstract
In the early 2000s, artemisinin-based combination therapy (ACT) was introduced as first-line treatment for uncomplicated Plasmodium falciparum malaria in virtually all endemic countries. However, despite the well-known excellent tolerability of ACTs, hypersensitivity to artemisinin derivatives remains a repeatedly documented adverse drug reaction of still unknown frequency. The clinical features of an artemisinin-induced hypersensitivity reaction range from mild to life-threatening severity, and a significant number of cases may pass unnoticed. In this review, we discuss the medical importance of hypersensitivity to artemisinin derivatives and we review data on the presumed frequency and its potential underlying mechanisms. Furthermore, we advocate to make alternative non-artemisinin-based drugs available for patients who do not tolerate artemisinin derivatives and to continue investing in the development of novel non-artemisinin-based combination regimens.
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Affiliation(s)
- Tamara Nordmann
- Department of Tropical Medicine, Bernhard Nocht Institute for Tropical Medicine and I. Department of Medicine, University Medical Center Hamburg-Eppendorf, Hamburg, Germany; German Centre for Infection Research (DZIF), partner site Hamburg-Luebeck-Borstel, Hamburg, Germany
| | - Steffen Borrmann
- Institute for Tropical Medicine, Eberhard Karls University of Tübingen, Tübingen, Germany; Centre de Recherches Médicale de Lambaréné (CERMEL), Lambaréné, Gabon
| | - Michael Ramharter
- Department of Tropical Medicine, Bernhard Nocht Institute for Tropical Medicine and I. Department of Medicine, University Medical Center Hamburg-Eppendorf, Hamburg, Germany; German Centre for Infection Research (DZIF), partner site Hamburg-Luebeck-Borstel, Hamburg, Germany; Centre de Recherches Médicale de Lambaréné (CERMEL), Lambaréné, Gabon.
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18
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Tisnerat C, Dassonville-Klimpt A, Gosselet F, Sonnet P. Antimalarial drug discovery: from quinine to the most recent promising clinical drug candidates. Curr Med Chem 2021; 29:3326-3365. [PMID: 34344287 DOI: 10.2174/0929867328666210803152419] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2021] [Revised: 06/10/2021] [Accepted: 06/11/2021] [Indexed: 11/22/2022]
Abstract
Malaria is a tropical threatening disease caused by Plasmodium parasites, resulting in 409,000 deaths in 2019. The delay of mortality and morbidity has been compounded by the widespread of drug resistant parasites from Southeast Asia since two decades. The emergence of artemisinin-resistant Plasmodium in Africa, where most cases are accounted, highlights the urgent need for new medicines. In this effort, the World Health Organization and Medicines for Malaria Venture joined to define clear goals for novel therapies and characterized the target candidate profile. This ongoing search for new treatments is based on imperative labor in medicinal chemistry which is summarized here with particular attention to hit-to-lead optimizations, key properties, and modes of action of these novel antimalarial drugs. This review, after presenting the current antimalarial chemotherapy, from quinine to the latest marketed drugs, focuses in particular on recent advances of the most promising antimalarial candidates in clinical and preclinical phases.
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Affiliation(s)
- Camille Tisnerat
- AGIR UR4294, UFR de Pharmacie, Université de Picardie Jules Verne, Amiens. France
| | | | | | - Pascal Sonnet
- AGIR UR4294, UFR de Pharmacie, Université de Picardie Jules Verne, Amiens. France
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19
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Shackleford DM, Chiu FCK, Katneni K, Blundell S, McLaren J, Wang X, Zhou L, Sriraghavan K, Alker AM, Hunziker D, Scheurer C, Zhao Q, Dong Y, Möhrle JJ, Abla N, Matile H, Wittlin S, Vennerstrom JL, Charman SA. Cytochrome P450-Mediated Metabolism and CYP Inhibition for the Synthetic Peroxide Antimalarial OZ439. ACS Infect Dis 2021; 7:1885-1893. [PMID: 34101429 PMCID: PMC8802618 DOI: 10.1021/acsinfecdis.1c00225] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
OZ439 is a potent synthetic ozonide evaluated for the treatment of uncomplicated malaria. The metabolite profile of OZ439 was characterized in vitro using human liver microsomes combined with LC/MS-MS, chemical derivatization, and metabolite synthesis. The primary biotransformations were monohydroxylation at the three distal carbon atoms of the spiroadamantane substructure, with minor contributions from N-oxidation of the morpholine nitrogen and deethylation cleavage of the morpholine ring. Secondary transformations resulted in the formation of dihydroxylation metabolites and metabolites containing both monohydroxylation and morpholine N-oxidation. With the exception of two minor metabolites, none of the other metabolites had appreciable antimalarial activity. Reaction phenotyping indicated that CYP3A4 is the enzyme responsible for the metabolism of OZ439, and it was found to inhibit CYP3A via both direct and mechanism-based inhibition. Elucidation of the metabolic pathways and kinetics will assist with efforts to predict potential metabolic drug-drug interactions and support physiologically based pharmacokinetic (PBPK) modeling.
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Affiliation(s)
- David M Shackleford
- Centre for Drug Candidate Optimisation, Monash Institute of Pharmaceutical Sciences, Monash University (Parkville Campus), 381 Royal Parade, Parkville, Victoria 3052, Australia
| | - Francis C K Chiu
- Centre for Drug Candidate Optimisation, Monash Institute of Pharmaceutical Sciences, Monash University (Parkville Campus), 381 Royal Parade, Parkville, Victoria 3052, Australia
| | - Kasiram Katneni
- Centre for Drug Candidate Optimisation, Monash Institute of Pharmaceutical Sciences, Monash University (Parkville Campus), 381 Royal Parade, Parkville, Victoria 3052, Australia
| | - Scott Blundell
- Centre for Drug Candidate Optimisation, Monash Institute of Pharmaceutical Sciences, Monash University (Parkville Campus), 381 Royal Parade, Parkville, Victoria 3052, Australia
| | - Jenna McLaren
- Centre for Drug Candidate Optimisation, Monash Institute of Pharmaceutical Sciences, Monash University (Parkville Campus), 381 Royal Parade, Parkville, Victoria 3052, Australia
| | - Xiaofang Wang
- College of Pharmacy, University of Nebraska Medical Center, 986125 Nebraska Medical Center, Omaha, Nebraska 68198, United States
| | - Lin Zhou
- College of Pharmacy, University of Nebraska Medical Center, 986125 Nebraska Medical Center, Omaha, Nebraska 68198, United States
| | - Kamaraj Sriraghavan
- College of Pharmacy, University of Nebraska Medical Center, 986125 Nebraska Medical Center, Omaha, Nebraska 68198, United States
| | - André M Alker
- Roche Pharmaceutical Research and Early Development, Roche Innovation Center Basel, F. Hoffmann-La Roche Ltd, Grenzacherstrasse 124, CH-4070 Basel, Switzerland
| | - Daniel Hunziker
- Roche Pharmaceutical Research and Early Development, Roche Innovation Center Basel, F. Hoffmann-La Roche Ltd, Grenzacherstrasse 124, CH-4070 Basel, Switzerland
| | - Christian Scheurer
- Swiss Tropical and Public Health Institute, Socinstrasse 57, CH-4002 Basel, Switzerland
- University of Basel, CH-4003 Basel, Switzerland
| | - Qingjie Zhao
- College of Pharmacy, University of Nebraska Medical Center, 986125 Nebraska Medical Center, Omaha, Nebraska 68198, United States
| | - Yuxiang Dong
- College of Pharmacy, University of Nebraska Medical Center, 986125 Nebraska Medical Center, Omaha, Nebraska 68198, United States
| | - Jörg J Möhrle
- Medicines for Malaria Venture, 20 Route de Pré-Bois, CH-1215 Geneva 15, Switzerland
| | - Nada Abla
- Medicines for Malaria Venture, 20 Route de Pré-Bois, CH-1215 Geneva 15, Switzerland
| | - Hugues Matile
- Roche Pharmaceutical Research and Early Development, Roche Innovation Center Basel, F. Hoffmann-La Roche Ltd, Grenzacherstrasse 124, CH-4070 Basel, Switzerland
| | - Sergio Wittlin
- Swiss Tropical and Public Health Institute, Socinstrasse 57, CH-4002 Basel, Switzerland
- University of Basel, CH-4003 Basel, Switzerland
| | - Jonathan L Vennerstrom
- College of Pharmacy, University of Nebraska Medical Center, 986125 Nebraska Medical Center, Omaha, Nebraska 68198, United States
| | - Susan A Charman
- Centre for Drug Candidate Optimisation, Monash Institute of Pharmaceutical Sciences, Monash University (Parkville Campus), 381 Royal Parade, Parkville, Victoria 3052, Australia
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20
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Dini S, Zaloumis SG, Price DJ, Gobeau N, Kümmel A, Cherkaoui M, Moehrle JJ, McCarthy JS, Simpson JA. Seeking an optimal dosing regimen for OZ439/DSM265 combination therapy for treating uncomplicated falciparum malaria. J Antimicrob Chemother 2021; 76:2325-2334. [PMID: 34179977 DOI: 10.1093/jac/dkab181] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2021] [Accepted: 05/02/2021] [Indexed: 11/14/2022] Open
Abstract
BACKGROUND The efficacy of artemisinin-based combination therapies (ACTs), the first-line treatments for uncomplicated falciparum malaria, has been declining in malaria-endemic countries due to the emergence of malaria parasites resistant to these compounds. Novel alternative therapies are needed urgently to prevent the likely surge in morbidity and mortality due to failing ACTs. OBJECTIVES This study investigates the efficacy of the combination of two novel drugs, OZ439 and DSM265, using a biologically informed within-host mathematical model. METHODS A within-host model was developed, which accounts for the differential killing of these compounds against different stages of the parasite's life cycle and accommodates the pharmacodynamic interaction between the drugs. Data of healthy volunteers infected with falciparum malaria collected from four trials (three that administered OZ439 and DSM265 alone, and the fourth a combination of OZ439 and DSM265) were analysed. Model parameters were estimated in a hierarchical Bayesian framework. RESULTS The posterior predictive simulations of our model predicted that 800 mg of OZ439 combined with 450 mg of DSM265, which are within the safe and tolerable dose range, can provide above 90% cure rates 42 days after drug administration. CONCLUSIONS Our results show that the combination of OZ439 and DSM265 can be a promising alternative to replace ACTs. Our model can be used to inform future Phase 2 and 3 clinical trials of OZ439/DSM265, fast-tracking the deployment of this combination therapy in the regions where ACTs are failing. The dosing regimens that are shown to be efficacious and within safe and tolerable limits are suggested for future investigations.
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Affiliation(s)
- Saber Dini
- Centre for Epidemiology and Biostatistics, Melbourne School of Population and Global Health, University of Melbourne, Melbourne, Australia
| | - Sophie G Zaloumis
- Centre for Epidemiology and Biostatistics, Melbourne School of Population and Global Health, University of Melbourne, Melbourne, Australia
| | - David J Price
- Centre for Epidemiology and Biostatistics, Melbourne School of Population and Global Health, University of Melbourne, Melbourne, Australia.,Doherty Institute for Infection and Immunity, University of Melbourne and Royal Melbourne Hospital, Melbourne, Australia
| | | | | | | | | | - James S McCarthy
- Doherty Institute for Infection and Immunity, University of Melbourne and Royal Melbourne Hospital, Melbourne, Australia.,QIMR Berghofer Medical Research Institute, Brisbane, Australia
| | - Julie A Simpson
- Centre for Epidemiology and Biostatistics, Melbourne School of Population and Global Health, University of Melbourne, Melbourne, Australia
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21
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A randomized, double-blind, phase 2b study to investigate the efficacy, safety, tolerability and pharmacokinetics of a single-dose regimen of ferroquine with artefenomel in adults and children with uncomplicated Plasmodium falciparum malaria. Malar J 2021; 20:222. [PMID: 34011358 PMCID: PMC8135182 DOI: 10.1186/s12936-021-03749-4] [Citation(s) in RCA: 23] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2021] [Accepted: 04/28/2021] [Indexed: 12/17/2022] Open
Abstract
Background For uncomplicated Plasmodium falciparum malaria, highly efficacious single-dose treatments are expected to increase compliance and improve treatment outcomes, and thereby may slow the development of resistance. The efficacy and safety of a single-dose combination of artefenomel (800 mg) plus ferroquine (400/600/900/1200 mg doses) for the treatment of uncomplicated P. falciparum malaria were evaluated in Africa (focusing on children ≤ 5 years) and Asia. Methods The study was a randomized, double-blind, single-dose, multi-arm clinical trial in patients aged > 6 months to < 70 years, from six African countries and Vietnam. Patients were followed up for 63 days to assess treatment efficacy, safety and pharmacokinetics. The primary efficacy endpoint was the polymerase chain reaction (PCR)-adjusted adequate clinical and parasitological response (ACPR) at Day 28 in the Per-Protocol [PP] Set comprising only African patients ≤ 5 years. The exposure–response relationship for PCR-adjusted ACPR at Day 28 and prevalence of kelch-13 mutations were explored. Results A total of 373 patients were treated: 289 African patients ≤ 5 years (77.5%), 64 African patients > 5 years and 20 Asian patients. None of the treatment arms met the target efficacy criterion for PCR-adjusted ACPR at Day 28 (lower limit of 95% confidence interval [CI] > 90%). PCR-adjusted ACPR at Day 28 [95% CI] in the PP Set ranged from 78.4% [64.7; 88.7%] to 91.7% [81.6; 97.2%] for the 400 mg to 1200 mg ferroquine dose. Efficacy rates were low in Vietnamese patients, ranging from 20 to 40%. A clear relationship was found between drug exposure (artefenomel and ferroquine concentrations at Day 7) and efficacy (primary endpoint), with higher concentrations of both drugs resulting in higher efficacy. Six distinct kelch-13 mutations were detected in parasite isolates from 10/272 African patients (with 2 mutations known to be associated with artemisinin resistance) and 18/20 Asian patients (all C580Y mutation). Vomiting within 6 h of initial artefenomel administration was common (24.6%) and associated with lower drug exposures. Conclusion The efficacy of artefenomel/ferroquine combination was suboptimal in African children aged ≤ 5 years, the population of interest, and vomiting most likely had a negative impact on efficacy. Trial registration ClinicalTrials.gov, NCT02497612. Registered 14 Jul 2015, https://clinicaltrials.gov/ct2/show/NCT02497612?term=NCT02497612&draw=2&rank=1 Supplementary Information The online version contains supplementary material available at 10.1186/s12936-021-03749-4.
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22
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Wang CYT, Ballard EL, Pava Z, Marquart L, Gaydon J, Murphy SC, Whiley D, O'Rourke P, McCarthy JS. Analytical validation of a real-time hydrolysis probe PCR assay for quantifying Plasmodium falciparum parasites in experimentally infected human adults. Malar J 2021; 20:181. [PMID: 33838672 PMCID: PMC8035755 DOI: 10.1186/s12936-021-03717-y] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2020] [Accepted: 03/29/2021] [Indexed: 11/10/2022] Open
Abstract
Background Volunteer infection studies have become a standard model for evaluating drug efficacy against Plasmodium infections. Molecular techniques such as qPCR are used in these studies due to their ability to provide robust and accurate estimates of parasitaemia at increased sensitivity compared to microscopy. The validity and reliability of assays need to be ensured when used to evaluate the efficacy of candidate drugs in clinical trials. Methods A previously described 18S rRNA gene qPCR assay for quantifying Plasmodium falciparum in blood samples was evaluated. Assay performance characteristics including analytical sensitivity, reportable range, precision, accuracy and specificity were assessed using experimental data and data compiled from phase 1 volunteer infection studies conducted between 2013 and 2019. Guidelines for validation of laboratory-developed molecular assays were followed. Results The reportable range was 1.50 to 6.50 log10 parasites/mL with a limit of detection of 2.045 log10 parasites/mL of whole blood based on a parasite diluted standard series over this range. The assay was highly reproducible with minimal intra-assay (SD = 0.456 quantification cycle (Cq) units [0.137 log10 parasites/mL] over 21 replicates) and inter-assay (SD = 0.604 Cq units [0.182 log10 parasites/mL] over 786 qPCR runs) variability. Through an external quality assurance program, the QIMR assay was shown to generate accurate results (quantitative bias + 0.019 log10 parasites/mL against nominal values). Specificity was 100% after assessing 164 parasite-free human blood samples. Conclusions The 18S rRNA gene qPCR assay is specific and highly reproducible and can provide reliable and accurate parasite quantification. The assay is considered fit for use in evaluating drug efficacy in malaria clinical trials. Supplementary Information The online version contains supplementary material available at 10.1186/s12936-021-03717-y.
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Affiliation(s)
- Claire Y T Wang
- Centre for Children's Health Research, Children's Health Queensland, Brisbane, Australia. .,Child Health Research Centre, The University of Queensland, Brisbane, Australia.
| | - Emma L Ballard
- QIMR Berghofer Medical Research Institute, Brisbane, Australia
| | - Zuleima Pava
- QIMR Berghofer Medical Research Institute, Brisbane, Australia
| | - Louise Marquart
- QIMR Berghofer Medical Research Institute, Brisbane, Australia
| | - Jane Gaydon
- Centre for Children's Health Research, Children's Health Queensland, Brisbane, Australia.,Child Health Research Centre, The University of Queensland, Brisbane, Australia
| | - Sean C Murphy
- Departments of Laboratory Medicine and Microbiology, University of Washington, Seattle, WA, USA.,Center for Emerging and Re-Emerging Infectious Diseases, University of Washington, Seattle, WA, USA
| | - David Whiley
- Centre for Children's Health Research, Children's Health Queensland, Brisbane, Australia.,UQ Centre for Clinical Research, Faculty of Medicine, The University of Queensland, Brisbane, Australia
| | - Peter O'Rourke
- QIMR Berghofer Medical Research Institute, Brisbane, Australia
| | - James S McCarthy
- QIMR Berghofer Medical Research Institute, Brisbane, Australia.,School of Medicine, The University of Queensland, Brisbane, Australia
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23
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Parasite-Host Dynamics throughout Antimalarial Drug Development Stages Complicate the Translation of Parasite Clearance. Antimicrob Agents Chemother 2021; 65:AAC.01539-20. [PMID: 33526486 PMCID: PMC8097426 DOI: 10.1128/aac.01539-20] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2020] [Accepted: 01/20/2021] [Indexed: 11/21/2022] Open
Abstract
Ensuring continued success against malaria depends on a pipeline of new antimalarials. Antimalarial drug development utilizes preclinical murine and experimental human malaria infection studies to evaluate drug efficacy. Ensuring continued success against malaria depends on a pipeline of new antimalarials. Antimalarial drug development utilizes preclinical murine and experimental human malaria infection studies to evaluate drug efficacy. A sequential approach is typically adapted, with results from each stage informing the design of the next stage of development. The validity of this approach depends on confidence that results from murine malarial studies predict the outcome of clinical trials in humans. Parasite clearance rates following treatment are key parameters of drug efficacy. To investigate the validity of forward predictions, we developed a suite of mathematical models to capture parasite growth and drug clearance along the drug development pathway and estimated parasite clearance rates. When comparing the three infection experiments, we identified different relationships of parasite clearance with dose and different maximum parasite clearance rates. In Plasmodium berghei-NMRI mouse infections, we estimated a maximum parasite clearance rate of 0.2 (1/h); in Plasmodium falciparum-SCID mouse infections, 0.05 (1/h); and in human volunteer infection studies with P. falciparum, we found a maximum parasite clearance rate of 0.12 (1/h) and 0.18 (1/h) after treatment with OZ439 and MMV048, respectively. Sensitivity analysis revealed that host-parasite driven processes account for up to 25% of variance in parasite clearance for medium-high doses of antimalarials. Although there are limitations in translating parasite clearance rates across these experiments, they provide insight into characterizing key parameters of drug action and dose response and assist in decision-making regarding dosage for further drug development.
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24
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Chawla J, Oberstaller J, Adams JH. Targeting Gametocytes of the Malaria Parasite Plasmodium falciparum in a Functional Genomics Era: Next Steps. Pathogens 2021; 10:346. [PMID: 33809464 PMCID: PMC7999360 DOI: 10.3390/pathogens10030346] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2021] [Revised: 02/25/2021] [Accepted: 03/03/2021] [Indexed: 02/04/2023] Open
Abstract
Mosquito transmission of the deadly malaria parasite Plasmodium falciparum is mediated by mature sexual forms (gametocytes). Circulating in the vertebrate host, relatively few intraerythrocytic gametocytes are picked up during a bloodmeal to continue sexual development in the mosquito vector. Human-to-vector transmission thus represents an infection bottleneck in the parasite's life cycle for therapeutic interventions to prevent malaria. Even though recent progress has been made in the identification of genetic factors linked to gametocytogenesis, a plethora of genes essential for sexual-stage development are yet to be unraveled. In this review, we revisit P. falciparum transmission biology by discussing targetable features of gametocytes and provide a perspective on a forward-genetic approach for identification of novel transmission-blocking candidates in the future.
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Affiliation(s)
- Jyotsna Chawla
- Molecular Medicine, Morsani College of Medicine, University of South Florida, 12901 Bruce B Downs Blvd, MDC 7, Tampa, FL 33612, USA;
| | - Jenna Oberstaller
- Center for Global Health and Infectious Diseases Research and USF Genomics Program, College of Public Health, University of South Florida, 3720 Spectrum Blvd, Suite 404, Tampa, FL 33612, USA;
| | - John H. Adams
- Center for Global Health and Infectious Diseases Research and USF Genomics Program, College of Public Health, University of South Florida, 3720 Spectrum Blvd, Suite 404, Tampa, FL 33612, USA;
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25
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Defining the Antimalarial Activity of Cipargamin in Healthy Volunteers Experimentally Infected with Blood-Stage Plasmodium falciparum. Antimicrob Agents Chemother 2021; 65:AAC.01423-20. [PMID: 33199389 PMCID: PMC7849011 DOI: 10.1128/aac.01423-20] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2020] [Accepted: 11/08/2020] [Indexed: 12/11/2022] Open
Abstract
The spiroindolone cipargamin, a new antimalarial compound that inhibits Plasmodium ATP4, is currently in clinical development. This study aimed to characterize the antimalarial activity of cipargamin in healthy volunteers experimentally infected with blood-stage Plasmodium falciparum. The spiroindolone cipargamin, a new antimalarial compound that inhibits Plasmodium ATP4, is currently in clinical development. This study aimed to characterize the antimalarial activity of cipargamin in healthy volunteers experimentally infected with blood-stage Plasmodium falciparum. Eight subjects were intravenously inoculated with parasite-infected erythrocytes and received a single oral dose of 10 mg cipargamin 7 days later. Blood samples were collected to monitor the development and clearance of parasitemia and plasma cipargamin concentrations. Parasite regrowth was treated with piperaquine monotherapy to clear asexual parasites, while allowing gametocyte transmissibility to mosquitoes to be investigated. An initial rapid decrease in parasitemia occurred in all participants following cipargamin dosing, with a parasite clearance half-life of 3.99 h. As anticipated from the dose selected, parasite regrowth occurred in all 8 subjects 3 to 8 days after dosing and allowed the pharmacokinetic/pharmacodynamic relationship to be determined. Based on the limited data from the single subtherapeutic dose cohort, a MIC of 11.6 ng/ml and minimum parasiticidal concentration that achieves 90% of maximum effect of 23.5 ng/ml were estimated, and a single 95-mg dose (95% confidence interval [CI], 50 to 270) was predicted to clear 109 parasites/ml. Low gametocyte densities were detected in all subjects following piperaquine treatment, which did not transmit to mosquitoes. Serious adverse liver function changes were observed in three subjects, which led to premature study termination. The antimalarial activity characterized in this study supports the further clinical development of cipargamin as a new treatment for P. falciparum malaria, although the hepatic safety profile of the compound warrants further evaluation. (This study has been registered at ClinicalTrials.gov under identifier NCT02543086.)
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26
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Driving antimalarial design through understanding of target mechanism. Biochem Soc Trans 2020; 48:2067-2078. [PMID: 32869828 PMCID: PMC7609028 DOI: 10.1042/bst20200224] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2020] [Revised: 07/23/2020] [Accepted: 07/27/2020] [Indexed: 11/17/2022]
Abstract
Malaria continues to be a global health threat, affecting approximately 219 million people in 2018 alone. The recurrent development of resistance to existing antimalarials means that the design of new drug candidates must be carefully considered. Understanding of drug target mechanism can dramatically accelerate early-stage target-based development of novel antimalarials and allows for structural modifications even during late-stage preclinical development. Here, we have provided an overview of three promising antimalarial molecular targets, PfDHFR, PfDHODH and PfA-M1, and their associated inhibitors which demonstrate how mechanism can inform drug design and be effectively utilised to generate compounds with potent inhibitory activity.
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