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Pottenger AE, Roy D, Srinivasan S, Chavas TEJ, Vlaskin V, Ho DK, Livingston VC, Maktabi M, Lin H, Zhang J, Pybus B, Kudyba K, Roth A, Senter P, Tyson G, Huber HE, Wesche D, Rochford R, Burke PA, Stayton PS. Liver-targeted polymeric prodrugs delivered subcutaneously improve tafenoquine therapeutic window for malaria radical cure. Sci Adv 2024; 10:eadk4492. [PMID: 38640243 PMCID: PMC11029812 DOI: 10.1126/sciadv.adk4492] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/05/2023] [Accepted: 03/19/2024] [Indexed: 04/21/2024]
Abstract
Approximately 3.3 billion people live with the threat of Plasmodium vivax malaria. Infection can result in liver-localized hypnozoites, which when reactivated cause relapsing malaria. This work demonstrates that an enzyme-cleavable polymeric prodrug of tafenoquine addresses key requirements for a mass administration, eradication campaign: excellent subcutaneous bioavailability, complete parasite control after a single dose, improved therapeutic window compared to the parent oral drug, and low cost of goods sold (COGS) at less than $1.50 per dose. Liver targeting and subcutaneous dosing resulted in improved liver:plasma exposure profiles, with increased efficacy and reduced glucose 6-phosphate dehydrogenase-dependent hemotoxicity in validated preclinical models. A COGS and manufacturability analysis demonstrated global scalability, affordability, and the ability to redesign this fully synthetic polymeric prodrug specifically to increase global equity and access. Together, this polymer prodrug platform is a candidate for evaluation in human patients and shows potential for P. vivax eradication campaigns.
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Affiliation(s)
- Ayumi E. Pottenger
- Department of Bioengineering, University of Washington, Seattle, WA 98195, USA
| | - Debashish Roy
- Department of Bioengineering, University of Washington, Seattle, WA 98195, USA
| | - Selvi Srinivasan
- Department of Bioengineering, University of Washington, Seattle, WA 98195, USA
| | - Thomas E. J. Chavas
- Department of Bioengineering, University of Washington, Seattle, WA 98195, USA
| | - Vladmir Vlaskin
- Department of Bioengineering, University of Washington, Seattle, WA 98195, USA
| | - Duy-Khiet Ho
- Department of Bioengineering, University of Washington, Seattle, WA 98195, USA
| | | | - Mahdi Maktabi
- Department of Immunology and Microbiology, University of Colorado Anschutz School of Medicine, Aurora, CO 80045, USA
| | - Hsiuling Lin
- Department of Drug Discovery, Experimental Therapeutics Branch, Walter Reed Army Institute of Research, Silver Spring, MD 20910, USA
| | - Jing Zhang
- Department of Drug Discovery, Experimental Therapeutics Branch, Walter Reed Army Institute of Research, Silver Spring, MD 20910, USA
| | - Brandon Pybus
- Department of Drug Discovery, Experimental Therapeutics Branch, Walter Reed Army Institute of Research, Silver Spring, MD 20910, USA
| | - Karl Kudyba
- Department of Drug Discovery, Experimental Therapeutics Branch, Walter Reed Army Institute of Research, Silver Spring, MD 20910, USA
| | - Alison Roth
- Department of Drug Discovery, Experimental Therapeutics Branch, Walter Reed Army Institute of Research, Silver Spring, MD 20910, USA
| | | | - George Tyson
- George Tyson Consulting, Los Altos Hills, CA 94022, USA
- Department of Chemical and Biomolecular Engineering, University of California, Berkeley, Berkeley, CA 94720, USA
| | - Hans E. Huber
- BioTD Strategies LLC, 213 Abbey Ln., Lansdale, PA 19446, USA
| | | | - Rosemary Rochford
- Department of Immunology and Microbiology, University of Colorado Anschutz School of Medicine, Aurora, CO 80045, USA
| | - Paul A. Burke
- Department of Bioengineering, University of Washington, Seattle, WA 98195, USA
- Burke Bioventures LLC, 1 Broadway 14th Floor, Cambridge, MA 02142, USA
| | - Patrick S. Stayton
- Department of Bioengineering, University of Washington, Seattle, WA 98195, USA
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Moyo P, Invernizzi L, Mianda SM, Rudolph W, Andayi AW, Wang M, Crouch NR, Maharaj VJ. Prioritised identification of structural classes of natural products from higher plants in the expedition of antimalarial drug discovery. Nat Prod Bioprospect 2023; 13:37. [PMID: 37821775 PMCID: PMC10567616 DOI: 10.1007/s13659-023-00402-2] [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] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/03/2023] [Accepted: 10/01/2023] [Indexed: 10/13/2023]
Abstract
The emergence and spread of drug-recalcitrant Plasmodium falciparum parasites threaten to reverse the gains made in the fight against malaria. Urgent measures need to be taken to curb this impending challenge. The higher plant-derived sesquiterpene, quinoline alkaloids, and naphthoquinone natural product classes of compounds have previously served as phenomenal chemical scaffolds from which integral antimalarial drugs were developed. Historical successes serve as an inspiration for the continued investigation of plant-derived natural products compounds in search of novel molecular templates from which new antimalarial drugs could be developed. The aim of this study was to identify potential chemical scaffolds for malaria drug discovery following analysis of historical data on phytochemicals screened in vitro against P. falciparum. To identify these novel scaffolds, we queried an in-house manually curated database of plant-derived natural product compounds and their in vitro biological data. Natural products were assigned to different structural classes using NPClassifier. To identify the most promising chemical scaffolds, we then correlated natural compound class with bioactivity and other data, namely (i) potency, (ii) resistance index, (iii) selectivity index and (iv) physicochemical properties. We used an unbiased scoring system to rank the different natural product classes based on the assessment of their bioactivity data. From this analysis we identified the top-ranked natural product pathway as the alkaloids. The top three ranked super classes identified were (i) pseudoalkaloids, (ii) naphthalenes and (iii) tyrosine alkaloids and the top five ranked classes (i) quassinoids (of super class triterpenoids), (ii) steroidal alkaloids (of super class pseudoalkaloids) (iii) cycloeudesmane sesquiterpenoids (of super class triterpenoids) (iv) isoquinoline alkaloids (of super class tyrosine alkaloids) and (v) naphthoquinones (of super class naphthalenes). Launched chemical space of these identified classes of compounds was, by and large, distinct from that of 'legacy' antimalarial drugs. Our study was able to identify chemical scaffolds with acceptable biological properties that are structurally different from current and previously used antimalarial drugs. These molecules have the potential to be developed into new antimalarial drugs.
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Affiliation(s)
- Phanankosi Moyo
- Department of Chemistry, Faculty of Natural and Agricultural Sciences, Biodiscovery Center, University of Pretoria, Private Bag X 20, Hatfield, Pretoria, 0028, South Africa
| | - Luke Invernizzi
- Department of Chemistry, Faculty of Natural and Agricultural Sciences, Biodiscovery Center, University of Pretoria, Private Bag X 20, Hatfield, Pretoria, 0028, South Africa
| | - Sephora M Mianda
- Department of Chemistry, Faculty of Natural and Agricultural Sciences, Biodiscovery Center, University of Pretoria, Private Bag X 20, Hatfield, Pretoria, 0028, South Africa
| | - Wiehan Rudolph
- Department of Chemistry, Faculty of Natural and Agricultural Sciences, Biodiscovery Center, University of Pretoria, Private Bag X 20, Hatfield, Pretoria, 0028, South Africa
| | - Andrew W Andayi
- Department of Physical and Biological Sciences, Murang'a University of Technology Murang'a, Murang'a, Kenya
| | - Mingxun Wang
- Computer Science and Engineering, University of California Riverside, 900 University Ave, Riverside, CA, 92521, USA
| | - Neil R Crouch
- Biodiversity Research and Monitoring Directorate, South African National Biodiversity Institute, Berea Road, P.O. Box 52099, Durban, 4007, South Africa
- School of Chemistry and Physics, University of KwaZulu-Natal, Durban, 4041, South Africa
| | - Vinesh J Maharaj
- Department of Chemistry, Faculty of Natural and Agricultural Sciences, Biodiscovery Center, University of Pretoria, Private Bag X 20, Hatfield, Pretoria, 0028, South Africa.
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Sutanto I, Soebandrio A, Ekawati LL, Chand K, Noviyanti R, Satyagraha AW, Subekti D, Santy YW, Crenna-Darusallam C, Instiaty I, Budiman W, Prasetya CB, Lardo S, Elyazar I, Duparc S, Cedar E, Rolfe K, Fernando D, Berni A, Jones S, Kleim JP, Fletcher K, Sharma H, Martin A, Taylor M, Goyal N, Green JA, Tan LK, Baird JK. Tafenoquine co-administered with dihydroartemisinin-piperaquine for the radical cure of Plasmodium vivax malaria (INSPECTOR): a randomised, placebo-controlled, efficacy and safety study. Lancet Infect Dis 2023; 23:1153-1163. [PMID: 37236221 PMCID: PMC10533414 DOI: 10.1016/s1473-3099(23)00213-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/31/2022] [Revised: 03/07/2023] [Accepted: 03/21/2023] [Indexed: 05/28/2023]
Abstract
BACKGROUND Tafenoquine, co-administered with chloroquine, is approved for the radical cure (prevention of relapse) of Plasmodium vivax malaria. In areas of chloroquine resistance, artemisinin-based combination therapies are used to treat malaria. This study aimed to evaluate tafenoquine plus the artemisinin-based combination therapy dihydroartemisinin-piperaquine for the radical cure of P vivax malaria. METHODS In this double-blind, double-dummy, parallel group study, glucose-6-phosphate dehydrogenase-normal Indonesian soldiers with microscopically confirmed P vivax malaria were randomly assigned by means of a computer-generated randomisation schedule (1:1:1) to dihydroartemisinin-piperaquine alone, dihydroartemisinin-piperaquine plus a masked single 300-mg dose of tafenoquine, or dihydroartemisinin-piperaquine plus 14 days of primaquine (15 mg). The primary endpoint was 6-month relapse-free efficacy following tafenoquine plus dihydroartemisinin-piperaquine versus dihydroartemisinin-piperaquine alone in all randomly assigned patients who received at least one dose of masked treatment and had microscopically confirmed P vivax at baseline (microbiological intention-to-treat population). Safety was a secondary outcome and the safety population comprised all patients who received at least one dose of masked medication. This study is registered with ClinicalTrials.gov, NCT02802501 and is completed. FINDINGS Between April 8, 2018, and Feb 4, 2019, of 164 patients screened for eligibility, 150 were randomly assigned (50 per treatment group). 6-month Kaplan-Meier relapse-free efficacy (microbiological intention to treat) was 11% (95% CI 4-22) in patients treated with dihydroartemisinin-piperaquine alone versus 21% (11-34) in patients treated with tafenoquine plus dihydroartemisinin-piperaquine (hazard ratio 0·44; 95% CI [0·29-0·69]) and 52% (37-65) in the primaquine plus dihydroartemisinin-piperaquine group. Adverse events over the first 28 days were reported in 27 (54%) of 50 patients treated with dihydroartemisinin-piperaquine alone, 29 (58%) of 50 patients treated with tafenoquine plus dihydroartemisinin-piperaquine, and 22 (44%) of 50 patients treated with primaquine plus dihydroartemisinin-piperaquine. Serious adverse events were reported in one (2%) of 50, two (4%) of 50, and two (4%) of 50 of patients, respectively. INTERPRETATION Although tafenoquine plus dihydroartemisinin-piperaquine was statistically superior to dihydroartemisinin-piperaquine alone for the radical cure of P vivax malaria, the benefit was not clinically meaningful. This contrasts with previous studies in which tafenoquine plus chloroquine was clinically superior to chloroquine alone for radical cure of P vivax malaria. FUNDING ExxonMobil, Bill & Melinda Gates Foundation, Newcrest Mining, UK Government all through Medicines for Malaria Venture; and GSK. TRANSLATION For the Indonesian translation of the abstract see Supplementary Materials section.
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Affiliation(s)
- Inge Sutanto
- Faculty of Medicine, University of Indonesia, Jakarta, Indonesia
| | | | - Lenny L Ekawati
- Faculty of Medicine, University of Indonesia, Jakarta, Indonesia; University of Oxford Clinical Research Unit-Indonesia, Jakarta, Indonesia
| | - Krisin Chand
- Faculty of Medicine, University of Indonesia, Jakarta, Indonesia; University of Oxford Clinical Research Unit-Indonesia, Jakarta, Indonesia
| | | | | | - Decy Subekti
- Faculty of Medicine, University of Indonesia, Jakarta, Indonesia; University of Oxford Clinical Research Unit-Indonesia, Jakarta, Indonesia
| | - Yulia Widya Santy
- Faculty of Medicine, University of Indonesia, Jakarta, Indonesia; University of Oxford Clinical Research Unit-Indonesia, Jakarta, Indonesia
| | - Chelzie Crenna-Darusallam
- Eijkman Institute for Molecular Biology, Jakarta, Indonesia; Mochtar Riady Institute for Nanotechnology, Banten, Indonesia
| | | | - Waras Budiman
- Health Service, Army of the Republic of Indonesia, Jakarta, Indonesia
| | | | - Soroy Lardo
- Health Service, Army of the Republic of Indonesia, Jakarta, Indonesia
| | - Iqbal Elyazar
- University of Oxford Clinical Research Unit-Indonesia, Jakarta, Indonesia
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | - J Kevin Baird
- Faculty of Medicine, University of Indonesia, Jakarta, Indonesia; University of Oxford Clinical Research Unit-Indonesia, Jakarta, Indonesia; Centre for Tropical Medicine and Global Health, Nuffield Department of Medicine, University of Oxford, Oxford, UK
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Yahiya S, Saunders CN, Hassan S, Straschil U, Fischer OJ, Rueda-Zubiaurre A, Haase S, Vizcay-Barrena G, Famodimu MT, Jordan S, Delves MJ, Tate EW, Barnard A, Fuchter MJ, Baum J. A novel class of sulphonamides potently block malaria transmission by targeting a Plasmodium vacuole membrane protein. Dis Model Mech 2023; 16:dmm049950. [PMID: 36715290 PMCID: PMC9934914 DOI: 10.1242/dmm.049950] [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] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2022] [Accepted: 12/13/2022] [Indexed: 01/31/2023] Open
Abstract
Phenotypic cell-based screens are critical tools for discovering candidate drugs for development, yet identification of the cellular target and mode of action of a candidate drug is often lacking. Using an imaging-based screen, we recently discovered an N-[(4-hydroxychroman-4-yl)methyl]-sulphonamide (N-4HCS) compound, DDD01035881, that blocks male gamete formation in the malaria parasite life cycle and subsequent transmission of the parasite to the mosquito with nanomolar activity. To identify the target(s) of DDD01035881, and of the N-4HCS class of compounds more broadly, we synthesised a photoactivatable derivative, probe 2. Photoaffinity labelling of probe 2 coupled with mass spectrometry identified the 16 kDa Plasmodium falciparum parasitophorous vacuole membrane protein Pfs16 as a potential parasite target. Complementary methods including cellular thermal shift assays confirmed that the parent molecule DDD01035881 stabilised Pfs16 in lysates from activated mature gametocytes. Combined with high-resolution, fluorescence and electron microscopy data, which demonstrated that parasites inhibited with N-4HCS compounds phenocopy the targeted deletion of Pfs16 in gametocytes, these data implicate Pfs16 as a likely target of DDD01035881. This finding establishes N-4HCS compounds as being flexible and effective starting candidates from which transmission-blocking antimalarials can be developed in the future.
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Affiliation(s)
- Sabrina Yahiya
- Department of Life Sciences, Imperial College London, Sir Alexander Fleming Building, Exhibition Road, South Kensington, London SW7 2AZ, UK
| | - Charlie N. Saunders
- Department of Life Sciences, Imperial College London, Sir Alexander Fleming Building, Exhibition Road, South Kensington, London SW7 2AZ, UK
- Department of Chemistry, Imperial College London, Molecular Sciences Research Hub, White City Campus, Wood Lane, London W12 OBZ, UK
| | - Sarah Hassan
- Department of Chemistry, Imperial College London, Molecular Sciences Research Hub, White City Campus, Wood Lane, London W12 OBZ, UK
| | - Ursula Straschil
- Department of Life Sciences, Imperial College London, Sir Alexander Fleming Building, Exhibition Road, South Kensington, London SW7 2AZ, UK
| | - Oliver J. Fischer
- Department of Chemistry, Imperial College London, Molecular Sciences Research Hub, White City Campus, Wood Lane, London W12 OBZ, UK
| | - Ainoa Rueda-Zubiaurre
- Department of Chemistry, Imperial College London, Molecular Sciences Research Hub, White City Campus, Wood Lane, London W12 OBZ, UK
| | - Silvia Haase
- Department of Life Sciences, Imperial College London, Sir Alexander Fleming Building, Exhibition Road, South Kensington, London SW7 2AZ, UK
| | - Gema Vizcay-Barrena
- Centre for Ultrastructural Imaging, New Hunt's House, Guy's Campus, King's College London, London SE1 1UL, UK
| | - Mufuliat Toyin Famodimu
- Department of Life Sciences, Imperial College London, Sir Alexander Fleming Building, Exhibition Road, South Kensington, London SW7 2AZ, UK
| | - Sarah Jordan
- Department of Life Sciences, Imperial College London, Sir Alexander Fleming Building, Exhibition Road, South Kensington, London SW7 2AZ, UK
| | - Michael J. Delves
- Department of Life Sciences, Imperial College London, Sir Alexander Fleming Building, Exhibition Road, South Kensington, London SW7 2AZ, UK
| | - Edward W. Tate
- Department of Chemistry, Imperial College London, Molecular Sciences Research Hub, White City Campus, Wood Lane, London W12 OBZ, UK
| | - Anna Barnard
- Department of Chemistry, Imperial College London, Molecular Sciences Research Hub, White City Campus, Wood Lane, London W12 OBZ, UK
| | - Matthew J. Fuchter
- Department of Chemistry, Imperial College London, Molecular Sciences Research Hub, White City Campus, Wood Lane, London W12 OBZ, UK
| | - Jake Baum
- Department of Life Sciences, Imperial College London, Sir Alexander Fleming Building, Exhibition Road, South Kensington, London SW7 2AZ, UK
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Ji S, Galon EM, Amer MM, Zafar I, Yanagawa M, Asada M, Zhou J, Liu M, Xuan X. Phosphatidylinositol 4-kinase is a viable target for the radical cure of Babesia microti infection in immunocompromised hosts. Front Cell Infect Microbiol 2022; 12:1048962. [DOI: 10.3389/fcimb.2022.1048962] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2022] [Accepted: 10/25/2022] [Indexed: 11/15/2022] Open
Abstract
Human babesiosis is a global emerging tick-borne disease caused by infection with intra-erythrocytic parasites of the genus Babesia. With the rise in human babesiosis cases, the discovery and development of new anti-Babesia drugs are essential. Phosphatidylinositol 4-kinase (PI4K) is a widely present eukaryotic enzyme that phosphorylates lipids to regulate intracellular signaling and trafficking. Previously, we have shown that MMV390048, an inhibitor of PI4K, showed potent inhibition against Babesia species, revealing PI4K as a druggable target for babesiosis. However, twice-administered, 7-day regimens failed to clear Babesia microti parasites from the immunocompromised host. Hence, in this study, we wanted to clarify whether targeting PI4K has the potential for the radical cure of babesiosis. In a B. microti-infected SCID mouse model, a 64-day-consecutive treatment with MMV390048 resulted in the clearance of parasites. Meanwhile, an atovaquone (ATO) resistant parasite line was isolated from the group treated with ATO plus azithromycin. A nonsynonymous variant in the Y272C of the cytochrome b gene was confirmed by sequencing. Likewise, MMV390048 showed potent inhibition against ATO-resistant parasites. These results provide evidence of PI4K as a viable drug target for the radical cure of babesiosis, which will contribute to designing new compounds that can eradicate parasites.
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Schneider KA, Salas CJ. Evolutionary genetics of malaria. Front Genet 2022; 13:1030463. [DOI: 10.3389/fgene.2022.1030463] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2022] [Accepted: 09/26/2022] [Indexed: 11/06/2022] Open
Abstract
Many standard-textbook population-genetic results apply to a wide range of species. Sometimes, however, population-genetic models and principles need to be tailored to a particular species. This is particularly true for malaria, which next to tuberculosis and HIV/AIDS ranks among the economically most relevant infectious diseases. Importantly, malaria is not one disease—five human-pathogenic species of Plasmodium exist. P. falciparum is not only the most severe form of human malaria, but it also causes the majority of infections. The second most relevant species, P. vivax, is already considered a neglected disease in several endemic areas. All human-pathogenic species have distinct characteristics that are not only crucial for control and eradication efforts, but also for the population-genetics of the disease. This is particularly true in the context of selection. Namely, fitness is determined by so-called fitness components, which are determined by the parasites live-history, which differs between malaria species. The presence of hypnozoites, i.e., dormant liver-stage parasites, which can cause disease relapses, is a distinct feature of P. vivax and P. ovale sp. In P. malariae inactivated blood-stage parasites can cause a recrudescence years after the infection was clinically cured. To properly describe population-genetic processes, such as the spread of anti-malarial drug resistance, these features must be accounted for appropriately. Here, we introduce and extend a population-genetic framework for the evolutionary dynamics of malaria, which applies to all human-pathogenic malaria species. The model focuses on, but is not limited to, the spread of drug resistance. The framework elucidates how the presence of dormant liver stage or inactivated blood stage parasites that act like seed banks delay evolutionary processes. It is shown that, contrary to standard population-genetic theory, the process of selection and recombination cannot be decoupled in malaria. Furthermore, we discuss the connection between haplotype frequencies, haplotype prevalence, transmission dynamics, and relapses or recrudescence in malaria.
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Noviyanti R, Carey-Ewend K, Trianty L, Parobek C, Puspitasari AM, Balasubramanian S, Park Z, Hathaway N, Utami RAS, Soebianto S, Jeny J, Yudhaputri F, Perkasa A, Coutrier FN, Tirta YK, Ekawati L, Tjahyono B, Sutanto I, Nelwan EJ, Sudoyo H, Baird JK, Lin JT. Hypnozoite depletion in successive Plasmodium vivax relapses. PLoS Negl Trop Dis 2022; 16:e0010648. [PMID: 35867730 PMCID: PMC9348653 DOI: 10.1371/journal.pntd.0010648] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2022] [Revised: 08/03/2022] [Accepted: 07/09/2022] [Indexed: 11/17/2022] Open
Abstract
Genotyping Plasmodium vivax relapses can provide insights into hypnozoite biology. We performed targeted amplicon sequencing of 127 relapses occurring in Indonesian soldiers returning to malaria-free Java after yearlong deployment in malarious Eastern Indonesia. Hepatic carriage of multiple hypnozoite clones was evident in three-quarters of soldiers with two successive relapses, yet the majority of relapse episodes only displayed one clonal population. The number of clones detected in relapse episodes decreased over time and through successive relapses, especially in individuals who received hypnozoiticidal therapy. Interrogating the multiplicity of infection in this P. vivax relapse cohort reveals evidence of independent activation and slow depletion of hypnozoites over many months by multiple possible mechanisms, including parasite senescence and host immunity. Investigating relapse patterns in infections of Plasmodium vivax, a parasite that causes malaria, is challenging due to concurrent reinfection events alongside true relapses in most clinical cohorts. We performed sequencing on P. vivax samples from a cohort of Indonesian soldiers who were exposed to the parasite while deployed in a malaria-endemic region and then experienced relapses after their return to a region with no current malaria transmission. From these true relapses, we show that most infected individuals harbor multiple lineages of hypnozoites (latent liver stage parasites that reactivate to cause relapse) but individual relapses are largely driven by a single hypnozoite lineage or clone. Additionally, the average number of parasite clones detected in each relapse decreases over time. These findings suggest that P. vivax hypnozoites activate independently from each other and that their population in the liver decreases over time after the initial infection, possibly due to immune clearance or loss of parasite viability.
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Affiliation(s)
| | - Kelly Carey-Ewend
- Gillings School of Global Public Health, University of North Carolina, Chapel Hill, North Carolina, United States of America
- University of North Carolina School of Medicine, Chapel Hill, North Carolina, United States of America
- * E-mail: (KCE); (JTL)
| | - Leily Trianty
- Eijkman Institute for Molecular Biology, Jakarta, Indonesia
| | - Christian Parobek
- University of North Carolina School of Medicine, Chapel Hill, North Carolina, United States of America
| | | | - Sujata Balasubramanian
- University of North Carolina School of Medicine, Chapel Hill, North Carolina, United States of America
| | - Zackary Park
- University of North Carolina School of Medicine, Chapel Hill, North Carolina, United States of America
| | - Nicholas Hathaway
- University of Massachusetts Chan Medical School of Medicine, Worcester, Massachusetts, United States of America
| | | | | | - Jeny Jeny
- Eijkman-Oxford Clinical Research Unit, Jakarta, Indonesia
| | | | - Aditya Perkasa
- Eijkman Institute for Molecular Biology, Jakarta, Indonesia
| | | | | | - Lenny Ekawati
- Eijkman-Oxford Clinical Research Unit, Jakarta, Indonesia
| | - Bagus Tjahyono
- Health Services, Army of the Republic of Indonesia, Jakarta, Indonesia
| | - Inge Sutanto
- Faculty of Medicine, University of Indonesia, Jakarta, Indonesia
| | - Erni J. Nelwan
- Faculty of Medicine, University of Indonesia, Jakarta, Indonesia
| | | | - J. Kevin Baird
- Eijkman Institute for Molecular Biology, Jakarta, Indonesia
- Faculty of Medicine, University of Indonesia, Jakarta, Indonesia
| | - Jessica T. Lin
- University of North Carolina School of Medicine, Chapel Hill, North Carolina, United States of America
- * E-mail: (KCE); (JTL)
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Lim W, Verbon A, van de Sande W. Identifying novel drugs with new modes of action for neglected tropical fungal skin diseases (fungal skinNTDs) using an Open Source Drug discovery approach. Expert Opin Drug Discov 2022; 17:641-659. [PMID: 35612364 DOI: 10.1080/17460441.2022.2080195] [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] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
INTRODUCTION The three fungal skin neglected tropical diseases (NTD) mycetoma, chromoblastomycosis and sporotrichosis currently lack prioritization and support to establish drug discovery programs in search for novel treatment options. This has made the efforts to identify novel drugs for these skinNTDs fragmented. AREAS COVERED To help escalate the discovery of novel drugs to treat these fungal skinNTDs, the authors have prepared an overview of the compounds with activity against fungal skinNTDs by analyzing data from individual drug discovery studies including those performed on the Medicines for Malaria Venture (MMV) open access boxes. EXPERT OPINION The authors were unable to identify studies in which causative agents of all three skinNTDs were included, indicating that an integrated approach is currently lacking. From the currently available data, the azoles and iodoquinol were the only compounds with activity against causative agents from the three different fungal skinNTDs. Fungal melanin inhibition enhanced the activity of antifungal agents. For mycetoma, the fenarimols, aminothiazoles and benzimidazole carbamates are currently being investigated in the MycetOS initiative. To come to a more integrated approach to identify drugs active against all three fungal skinNTDs, compounds made in the MycetOS initiative could also be explored for chromoblastomycosis and sporotrichosis.
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Affiliation(s)
- Wilson Lim
- Department of Microbiology and Infectious Diseases, Erasmus MC, University Medical Center Rotterdam, Rotterdam, The Netherlands
| | - Annelies Verbon
- Department of Microbiology and Infectious Diseases, Erasmus MC, University Medical Center Rotterdam, Rotterdam, The Netherlands
| | - Wendy van de Sande
- Department of Microbiology and Infectious Diseases, Erasmus MC, University Medical Center Rotterdam, Rotterdam, The Netherlands
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Abstract
INTRODUCTION Plasmodium vivax malaria causes significant disease burden worldwide, especially in Latin America, Southeast Asia, and Oceania. P. vivax is characterized by the production of liver hypnozoites that cause clinical relapses upon periodic activation. Primaquine, an 8-aminoquinoline drug, has been the standard of care for decades to treat liver-stage P. vivax malaria; however, it requires long treatment regimens (one to two weeks) that lead to poor adherence and thus clinical relapses. Tafenoquine (TFQ), a newly available and efficacious single-dose 8-aminoquinoline, aims to address this challenge. Safe administration is possible when paired with the use of glucose-6-phosphate dehydrogenase (G6PD) diagnostics to prevent 8-aminoquinoline-induced hemolysis in patients with underlying G6PD deficiency (G6PDd). AREAS COVERED In this review, the authors present the recent literature regarding the pharmacology, efficacy, safety, and tolerability of TFQ and highlight regional differences in these areas. The authors also discuss the potential for TFQ, complemented with primaquine PQ and effective screening for G6PDd, to improve P. vivax clinical management and facilitate targeted mass drug administration in communities to decrease transmission. EXPERT OPINION Clinical studies show therapeutic efficacy of TFQ as well as a good performance in terms of safety and tolerability. Additional research regarding the effectiveness and safety TFQ in malaria elimination strategies such as targeted or mass drug administration are needed.
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Affiliation(s)
| | - Paulo Manrrique
- Department of Immunology and Infectious Diseases, Harvard T.H. Chan School of Public Health, Boston, PA, USA
| | - Angel Rosas-Aguirre
- Public Health and Administration, Universidad Peruana Cayetano Heredia, Lima, Peru
| | - Sonia Herrera
- Department of Epidemiology, Division of Infectious Diseases and Global Health, Department of Pediatrics, Division of Pediatric Infectious Diseases, University of California San Francisco, San Francisco, CA, United States
| | - Michelle S Hsiang
- Department of Epidemiology, Division of Infectious Diseases and Global Health, Department of Pediatrics, Division of Pediatric Infectious Diseases, University of California San Francisco, San Francisco, CA, United States.,Department of Epidemiology and Biostatistics, University of California San Francisco (UCSF), San Francisco, CA, USA.,Department of PediatricsUniversity of California San Francisco (UCSF), San Francisco, CA, USA
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10
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Watson JA, Commons RJ, Tarning J, Simpson JA, Llanos Cuentas A, Lacerda MVG, Green JA, Koh GCKW, Chu CS, Nosten FH, Price RN, Day NPJ, White NJ. The clinical pharmacology of tafenoquine in the radical cure of Plasmodium vivax malaria: An individual patient data meta-analysis. eLife 2022; 11:83433. [PMID: 36472067 PMCID: PMC9725750 DOI: 10.7554/elife.83433] [Citation(s) in RCA: 14] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2022] [Accepted: 11/21/2022] [Indexed: 12/12/2022] Open
Abstract
Tafenoquine is a newly licensed antimalarial drug for the radical cure of Plasmodium vivax malaria. The mechanism of action and optimal dosing are uncertain. We pooled individual data from 1102 patients and 72 healthy volunteers studied in the pre-registration trials. We show that tafenoquine dose is the primary determinant of efficacy. Under an Emax model, we estimate the currently recommended 300 mg dose in a 60 kg adult (5 mg/kg) results in 70% of the maximal obtainable hypnozoiticidal effect. Increasing the dose to 7.5 mg/kg (i.e. 450 mg) would result in 90% reduction in the risk of P. vivax recurrence. After adjustment for dose, the tafenoquine terminal elimination half-life, and day 7 methaemoglobin concentration, but not the parent compound exposure, were also associated with recurrence. These results suggest that the production of oxidative metabolites is central to tafenoquine's hypnozoiticidal efficacy. Clinical trials of higher tafenoquine doses are needed to characterise their efficacy, safety and tolerability.
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Affiliation(s)
- James A Watson
- Oxford University Clinical Research Unit, Hospital for Tropical DiseasesHo Chi Minh CityViet Nam,Centre for Tropical Medicine and Global Health, Nuffield Department of Medicine, University of OxfordOxfordUnited Kingdom,WorldWide Antimalarial Resistance NetworkOxfordUnited Kingdom
| | - Robert J Commons
- WorldWide Antimalarial Resistance NetworkOxfordUnited Kingdom,Global Health Division, Menzies School of Health Research, Charles Darwin UniversityDarwinAustralia
| | - Joel Tarning
- Centre for Tropical Medicine and Global Health, Nuffield Department of Medicine, University of OxfordOxfordUnited Kingdom,Mahidol Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol UniversityBangkokThailand
| | - Julie A Simpson
- Centre for Epidemiology and Biostatistics, Melbourne School of Population and Global Health, University of MelbourneMelbourneAustralia
| | - Alejandro Llanos Cuentas
- Unit of Leishmaniasis and Malaria, Instituto de Medicina Tropical “Alexander von Humboldt”, Universidad Peruana Cayetano HerediaLimaPeru
| | | | - Justin A Green
- Formerly Senior Director, Global Health, GlaxoSmithKlineBrentfordUnited Kingdom
| | - Gavin CKW Koh
- Department of Infectious Diseases, Northwick Park HospitalHarrowUnited Kingdom
| | - Cindy S Chu
- Centre for Tropical Medicine and Global Health, Nuffield Department of Medicine, University of OxfordOxfordUnited Kingdom,Shoklo Malaria Research Unit, Mahidol–Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol UniversityMae SotThailand
| | - François H Nosten
- Centre for Tropical Medicine and Global Health, Nuffield Department of Medicine, University of OxfordOxfordUnited Kingdom,Shoklo Malaria Research Unit, Mahidol–Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol UniversityMae SotThailand
| | - Richard N Price
- Centre for Tropical Medicine and Global Health, Nuffield Department of Medicine, University of OxfordOxfordUnited Kingdom,WorldWide Antimalarial Resistance NetworkOxfordUnited Kingdom,Global Health Division, Menzies School of Health Research, Charles Darwin UniversityDarwinAustralia
| | - Nicholas PJ Day
- Centre for Tropical Medicine and Global Health, Nuffield Department of Medicine, University of OxfordOxfordUnited Kingdom,Mahidol Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol UniversityBangkokThailand
| | - Nicholas J White
- Centre for Tropical Medicine and Global Health, Nuffield Department of Medicine, University of OxfordOxfordUnited Kingdom,Mahidol Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol UniversityBangkokThailand
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11
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Markus MB. Safety and Efficacy of Tafenoquine for Plasmodium vivax Malaria Prophylaxis and Radical Cure: Overview and Perspectives. Ther Clin Risk Manag 2021; 17:989-999. [PMID: 34526770 PMCID: PMC8435617 DOI: 10.2147/tcrm.s269336] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2021] [Accepted: 08/20/2021] [Indexed: 11/23/2022] Open
Abstract
This article is inter alia a brief, first-stop guide to possible adverse events (AEs) associated with tafenoquine (TQ) intake. Safety and efficacy findings for TQ in Plasmodium vivax malaria prophylaxis and radical cure are summarized and some of the latest TQ-related studies (published in 2020 and 2021) are highlighted. In addition, little-known biological and other matters concerning malaria parasites and 8-aminoquinoline (8-AQ) drug action are discussed and some correct terminology pertinent to malaria is explained.
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Affiliation(s)
- Miles B Markus
- School of Animal, Plant and Environmental Sciences, Faculty of Science, University of the Witwatersrand, Johannesburg, South Africa
- Wits Research Institute for Malaria, School of Pathology, Faculty of Health Sciences, University of the Witwatersrand, Johannesburg, South Africa
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