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Kang DW, Kim JH, Kim KM, Cho SJ, Choi GW, Cho HY. Inter-Species Pharmacokinetic Modeling and Scaling for Drug Repurposing of Pyronaridine and Artesunate. Int J Mol Sci 2024; 25:6998. [PMID: 39000107 PMCID: PMC11241507 DOI: 10.3390/ijms25136998] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2024] [Revised: 06/23/2024] [Accepted: 06/25/2024] [Indexed: 07/16/2024] Open
Abstract
Even though several new targets (mostly viral infection) for drug repurposing of pyronaridine and artesunate have recently emerged in vitro and in vivo, inter-species pharmacokinetic (PK) data that can extend nonclinical efficacy to humans has not been reported over 30 years of usage. Since extrapolation of animal PK data to those of humans is essential to predict clinical outcomes for drug repurposing, this study aimed to investigate inter-species PK differences in three animal species (hamster, rat, and dog) and to support clinical translation of a fixed-dose combination of pyronaridine and artesunate. PK parameters (e.g., steady-state volume of distribution (Vss), clearance (CL), area under the concentration-time curve (AUC), mean residence time (MRT), etc.) of pyronaridine, artesunate, and dihydroartemisinin (an active metabolite of artesunate) were determined by non-compartmental analysis. In addition, one- or two-compartment PK modeling was performed to support inter-species scaling. The PK models appropriately described the blood concentrations of pyronaridine, artesunate, and dihydroartemisinin in all animal species, and the estimated PK parameters in three species were integrated for inter-species allometric scaling to predict human PKs. The simple allometric equation (Y = a × Wb) well explained the relationship between PK parameters and the actual body weight of animal species. The results from the study could be used as a basis for drug repurposing and support determining the effective dosage regimen for new indications based on in vitro/in vivo efficacy data and predicted human PKs in initial clinical trials.
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Affiliation(s)
| | | | | | | | | | - Hea-Young Cho
- College of Pharmacy, CHA University, 335 Pangyo-ro, Bundang-gu, Seongnam-si 13488, Gyeonggi-do, Republic of Korea; (D.W.K.); (J.H.K.); (K.M.K.); (S.-j.C.); (G.-W.C.)
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2
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Banda CG, Tarning J, Barnes KI. Use of population pharmacokinetic-pharmacodynamic modelling to inform antimalarial dose optimization in infants. Br J Clin Pharmacol 2024. [PMID: 38858224 DOI: 10.1111/bcp.16132] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2023] [Revised: 03/21/2024] [Accepted: 05/18/2024] [Indexed: 06/12/2024] Open
Abstract
Infants bear a significant malaria burden but are usually excluded from participating in early dose optimization studies that inform dosing regimens of antimalarial therapy. Unlike older children, infants' exclusion from early-phase trials has resulted in limited evidence to guide accurate dosing of antimalarial treatment for uncomplicated malaria or malaria-preventive treatment in this vulnerable population. Subsequently, doses used in infants are often extrapolated from older children or adults, with the potential for under- or overdosing. Population pharmacokinetic-pharmacodynamic (PK-PD) modelling, a quantitative methodology that applies mathematical and statistical techniques, can aid the design of clinical studies in infants that collect sparse pharmacokinetic data as well as support the analysis of such data to derive optimized antimalarial dosing in this complex and at-risk yet understudied subpopulation. In this review, we reflect on what PK-PD modelling can do in programmatic settings of most malaria-endemic areas and how it can be used to inform antimalarial dose optimization for preventive and curative treatment of uncomplicated malaria in infants. We outline key developmental physiological changes that affect drug exposure in early life, the challenges of conducting dose optimization studies in infants, and examples of how PK-PD modelling has previously informed antimalarial dose optimization in this subgroup. Additionally, we discuss the limitations and gaps of PK-PD modelling when used for dose optimization in infants. To utilize modelling well, there is a need to generate useful, sparse, PK and PD data in this subpopulation to inform antimalarial optimal dosing in infancy.
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Affiliation(s)
- Clifford G Banda
- Malawi-Liverpool-Wellcome Programme, Blantyre, Malawi
- Division of Clinical Pharmacology, Department of Medicine, University of Cape Town, Cape Town, South Africa
- Kamuzu University of Health Sciences (formerly College of Medicine and Kamuzu College of Nursing, University of Malawi), Blantyre, Malawi
| | - Joel Tarning
- Centre for Tropical Medicine and Global Health, Nuffield Department of Medicine, University of Oxford, Oxford, UK
- Mahidol Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand
| | - Karen I Barnes
- Division of Clinical Pharmacology, Department of Medicine, University of Cape Town, Cape Town, South Africa
- WorldWide Antimalarial Resistance Network (WWARN), Pharmacology Scientific Group, University of Cape Town, Cape Town, South Africa
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Watson JA, Peto TJ, White NJ. Rectal artesunate suppositories for the pre-referral treatment of suspected severe malaria. PLoS Med 2023; 20:e1004312. [PMID: 37943884 PMCID: PMC10681301 DOI: 10.1371/journal.pmed.1004312] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Revised: 11/27/2023] [Indexed: 11/12/2023] Open
Abstract
In this Policy Forum article, James A. Watson and colleagues discuss recent guidelines relating to pre-referral treatment of suspected severe malaria with rectal artesunate suppositories in remote areas.
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Affiliation(s)
- James A. Watson
- Oxford University Clinical Research Unit, Hospital for Tropical Diseases, Ho Chi Minh City, Vietnam
- Centre for Tropical Medicine and Global Health, Nuffield Department of Medicine, University of Oxford, New Richards Building, Old Road Campus, Roosevelt Drive, Oxford, United Kingdom
| | - Thomas J. Peto
- Centre for Tropical Medicine and Global Health, Nuffield Department of Medicine, University of Oxford, New Richards Building, Old Road Campus, Roosevelt Drive, Oxford, United Kingdom
- Mahidol Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand
| | - Nicholas J. White
- Centre for Tropical Medicine and Global Health, Nuffield Department of Medicine, University of Oxford, New Richards Building, Old Road Campus, Roosevelt Drive, Oxford, United Kingdom
- Mahidol Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand
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Watson JA, Peto TJ, White NJ. The CARAMAL study could not assess the effectiveness of rectal artesunate in treating suspected severe malaria. BMC Med 2023; 21:118. [PMID: 36991487 PMCID: PMC10060129 DOI: 10.1186/s12916-023-02776-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/07/2022] [Accepted: 02/09/2023] [Indexed: 03/31/2023] Open
Abstract
CARAMAL was a large observational study which recorded mortality in children with suspected severe malaria before and after the roll-out of rectal artesunate in Nigeria, Uganda and the Democratic Republic of the Congo. The results of CARAMAL have had a huge impact on public health policy leading to a World Health Organization moratorium on the roll-out of rectal artesunate. The conclusion reported in the abstract uses strong causal language, stating that "pre-referral RAS [rectal artesunate suppositories] had no beneficial effect on child survival". We argue that this causal interpretation of the study results is not justified. Data from the CARAMAL study inform chiefly on the strengths and weaknesses of referral systems in these three countries and do not inform reliably as to the beneficial effect of providing access to a known life-saving treatment.
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Affiliation(s)
- James A Watson
- Oxford University Clinical Research Unit, Hospital for Tropical Diseases, Ho Chi Minh City, Viet Nam.
- Centre for Tropical Medicine and Global Health, Nuffield Department of Medicine, University of Oxford, Oxford, UK.
| | - Thomas J Peto
- Centre for Tropical Medicine and Global Health, Nuffield Department of Medicine, University of Oxford, Oxford, UK
- Mahidol Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand
| | - Nicholas J White
- Centre for Tropical Medicine and Global Health, Nuffield Department of Medicine, University of Oxford, Oxford, UK
- Mahidol Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand
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5
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Brunner NC, Omoluabi E, Awor P, Okitawutshu J, Tshefu Kitoto A, Signorell A, Akano B, Ayodeji K, Okon C, Yusuf O, Athieno P, Kimera J, Tumukunde G, Angiro I, Kalenga JC, Delvento G, Lee TT, Lambiris MJ, Ross A, Cereghetti N, Visser T, Napier HG, Buj V, Burri C, Lengeler C, Hetzel MW. Prereferral rectal artesunate and referral completion among children with suspected severe malaria in the Democratic Republic of the Congo, Nigeria and Uganda. BMJ Glob Health 2022; 7:e008346. [PMID: 35580913 PMCID: PMC9114942 DOI: 10.1136/bmjgh-2021-008346] [Citation(s) in RCA: 13] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2021] [Accepted: 04/14/2022] [Indexed: 11/13/2022] Open
Abstract
INTRODUCTION Children who receive prereferral rectal artesunate (RAS) require urgent referral to a health facility where appropriate treatment for severe malaria can be provided. However, the rapid improvement of a child's condition after RAS administration may influence a caregiver's decision to follow this recommendation. Currently, the evidence on the effect of RAS on referral completion is limited. METHODS An observational study accompanied the roll-out of RAS in three malaria endemic settings in the Democratic Republic of the Congo (DRC), Nigeria and Uganda. Community health workers and primary health centres enrolled children under 5 years with suspected severe malaria before and after the roll-out of RAS. All children were followed up 28 days after enrolment to assess their treatment-seeking pathways. RESULTS Referral completion was 67% (1408/2104) in DRC, 48% (287/600) in Nigeria and 58% (2170/3745) in Uganda. In DRC and Uganda, RAS users were less likely to complete referral than RAS non-users in the pre-roll-out phase (adjusted OR (aOR)=0.48, 95% CI 0.30 to 0.77 and aOR=0.72, 95% CI 0.58 to 0.88, respectively). Among children seeking care from a primary health centre in Nigeria, RAS users were less likely to complete referral compared with RAS non-users in the post-roll-out phase (aOR=0.18, 95% CI 0.05 to 0.71). In Uganda, among children who completed referral, RAS users were significantly more likely to complete referral on time than RAS non-users enrolled in the pre-roll-out phase (aOR=1.81, 95% CI 1.17 to 2.79). CONCLUSIONS The findings of this study raise legitimate concerns that the roll-out of RAS may lead to lower referral completion in children who were administered prereferral RAS. To ensure that community-based programmes are effectively implemented, barriers to referral completion need to be addressed at all levels. Alternative effective treatment options should be provided to children unable to complete referral. TRIAL REGISTRSTION NUMBER NCT03568344; ClinicalTrials.gov.
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Affiliation(s)
- Nina C Brunner
- Swiss Tropical and Public Health Institute, Allschwil, Switzerland
- University of Basel, Basel, Switzerland
| | | | - Phyllis Awor
- Community Health and Behavioural Sciences, Makerere University School of Public Health, Kampala, Uganda
| | - Jean Okitawutshu
- Swiss Tropical and Public Health Institute, Allschwil, Switzerland
- Community Health, Kinshasa School of Public Health, Kinshasa, Democratic Republic of Congo
| | | | - Aita Signorell
- Swiss Tropical and Public Health Institute, Allschwil, Switzerland
- University of Basel, Basel, Switzerland
| | | | | | | | | | - Proscovia Athieno
- Community Health and Behavioural Sciences, Makerere University School of Public Health, Kampala, Uganda
| | - Joseph Kimera
- Community Health and Behavioural Sciences, Makerere University School of Public Health, Kampala, Uganda
| | - Gloria Tumukunde
- Community Health and Behavioural Sciences, Makerere University School of Public Health, Kampala, Uganda
| | - Irene Angiro
- Community Health and Behavioural Sciences, Makerere University School of Public Health, Kampala, Uganda
| | - Jean-Claude Kalenga
- Community Health, Kinshasa School of Public Health, Kinshasa, Democratic Republic of Congo
| | - Giulia Delvento
- Swiss Tropical and Public Health Institute, Allschwil, Switzerland
- University of Basel, Basel, Switzerland
| | - Tristan T Lee
- Swiss Tropical and Public Health Institute, Allschwil, Switzerland
- University of Basel, Basel, Switzerland
| | - Mark J Lambiris
- Swiss Tropical and Public Health Institute, Allschwil, Switzerland
- University of Basel, Basel, Switzerland
| | - Amanda Ross
- Swiss Tropical and Public Health Institute, Allschwil, Switzerland
- University of Basel, Basel, Switzerland
| | - Nadja Cereghetti
- Swiss Tropical and Public Health Institute, Allschwil, Switzerland
- University of Basel, Basel, Switzerland
| | - Theodoor Visser
- Global Malaria, Clinton Health Access Initiative, Boston, MA, USA
| | - Harriet G Napier
- Global Malaria, Clinton Health Access Initiative, Boston, MA, USA
| | - Valentina Buj
- Health/Child and Community Health Unit, UNICEF, New York, NY, USA
| | - Christian Burri
- Swiss Tropical and Public Health Institute, Allschwil, Switzerland
- University of Basel, Basel, Switzerland
| | - Christian Lengeler
- Swiss Tropical and Public Health Institute, Allschwil, Switzerland
- University of Basel, Basel, Switzerland
| | - Manuel W Hetzel
- Swiss Tropical and Public Health Institute, Allschwil, Switzerland
- University of Basel, Basel, Switzerland
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6
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Espíndola MR, Varotti FDP, Aguiar ACC, Andrade SN, Rocha EMMD. In vitro assessment for cytotoxicity screening of new antimalarial candidates. BRAZ J PHARM SCI 2022. [DOI: 10.1590/s2175-97902022e18308] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
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7
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Sugiarto SR, Page-Sharp M, Drinkwater JJ, Davis WA, Salman S, Davis TME. Pharmacokinetic properties of the antimalarial combination therapy artemether-lumefantrine in normal-weight, overweight and obese healthy male adults. Int J Antimicrob Agents 2021; 59:106482. [PMID: 34818520 DOI: 10.1016/j.ijantimicag.2021.106482] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2021] [Revised: 11/09/2021] [Accepted: 11/13/2021] [Indexed: 11/26/2022]
Abstract
The component drugs in the widely used antimalarial artemisinin combination therapy artemether-lumefantrine are lipophilic, with the possibility that recommended fixed doses in adults may lead to subtherapeutic concentrations and consequent treatment failure in overweight/obese individuals with malaria. The aim of this study was to investigate the pharmacokinetic properties of artemether, lumefantrine and their active metabolites dihydroartemisinin and desbutyl-lumefantrine in 16 normal-weight, overweight and obese healthy male volunteers [body mass index (BMI) categories ≤25 kg/m², >25-≤30 kg/m² and >30 kg/m², respectively; absolute range 19.3-37.2 kg/m²]. Participants received the conventional six doses of artemether-lumefantrine over 3 days, each dose comprising 80 mg artemether plus 480 mg lumefantrine administered with 6.7 g fat, and blood samples were collected at pre-specified time-points over 14 days. Plasma drug/metabolite concentrations were measured using liquid chromatography-mass spectrometry and included in multi-compartmental population pharmacokinetic models. There was a non-significant trend to a lower area under the plasma concentration-time curve with a higher body weight or BMI for dihydroartemisinin and especially artemether which was attenuated when normalized for mg/kg dose, but this relationship was not evident in the case of the more lipophilic lumefantrine and its metabolite desbutyl-lumefantrine. Simulated Day 7 plasma lumefantrine concentrations were >200 µg/L (the threshold at which Plasmodium falciparum recrudescences are minimized) in all participants. These results indicate that there is no need for artemether-lumefantrine dose modification in overweight and obese patients with malaria.
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Affiliation(s)
- Sri Riyati Sugiarto
- University of Western Australia, Medical School, Fremantle Hospital, Fremantle, Western Australia, Australia
| | - Madhu Page-Sharp
- Curtin University, School of Pharmacy and Biomedical Sciences, Bentley, Western Australia, Australia
| | - Jocelyn J Drinkwater
- University of Western Australia, Medical School, Fremantle Hospital, Fremantle, Western Australia, Australia
| | - Wendy A Davis
- University of Western Australia, Medical School, Fremantle Hospital, Fremantle, Western Australia, Australia
| | - Sam Salman
- University of Western Australia, Medical School, Fremantle Hospital, Fremantle, Western Australia, Australia; Clinical Pharmacology and Toxicology Unit, PathWest, Western Australia, Australia
| | - Timothy M E Davis
- University of Western Australia, Medical School, Fremantle Hospital, Fremantle, Western Australia, Australia.
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Pharmacokinetics and Toxicokinetics of Artemisinin-Hydroxychloroquine Sulfate Tablets in Rats and Dogs. EVIDENCE-BASED COMPLEMENTARY AND ALTERNATIVE MEDICINE 2021; 2021:6830459. [PMID: 34721641 PMCID: PMC8553450 DOI: 10.1155/2021/6830459] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/29/2021] [Revised: 08/12/2021] [Accepted: 09/22/2021] [Indexed: 11/18/2022]
Abstract
Artemisinin-hydroxychloroquine sulfate tablets (AH) are relatively inexpensive and a novel combination therapy for the treatment of all forms of malaria, especially aminoquinine drug-resistant strains of P. falciparum. Our aim was to assess the pharmacokinetics (PK) and toxicokinetics (TK) of AH following oral administration in Sprague Dawley rats and Beagle dogs by using the liquid chromatography tandem mass spectrometry methods (LC-MS/MS). The PK studies were carried out in eighteen rats at three doses and six dogs at three rounds of three doses after a single oral administration of AH. The TK studies in rats and dogs were accompanied by the 14-day repeated dosing studies. The PK results revealed that artemisinin was absorbed and cleared rapidly in rats with obvious gender difference and interindividual variability, and the systemic exposure with regard to AUC was positively correlated with the dosage in female rats. However, the kinetics parameters of artemisinin in dogs were not obtained because the plasma concentration was undetectable. The absorption and elimination of hydroxychloroquine in dogs and rats were relatively slow, and no gender difference was observed. The AUC of hydroxychloroquine showed a linear correlation with the dosage, but C max varied significantly among individuals. After 14-day repeated oral administration of AH, hydroxychloroquine shows an increase in systemic exposure and accumulation in rats and dogs, whereas the AUC and C max of artemisinin remarkably decreased in female rats due to its autoinduction metabolism. The TK results were basically consistent with the dose- and time-dependent toxic reaction in 14-day repeated dosing studies of AH in rats and dogs. The information from our studies could be helpful for further pharmacological and toxicological research and clinical application of AH.
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Fanello C, Hoglund RM, Lee SJ, Kayembe D, Ndjowo P, Kabedi C, Badjanga BB, Niamyim P, Tarning J, Woodrow C, Gomes M, Day NP, White NJ, Onyamboko MA. Pharmacokinetic Study of Rectal Artesunate in Children with Severe Malaria in Africa. Antimicrob Agents Chemother 2021; 65:e02223-20. [PMID: 33526485 PMCID: PMC8097454 DOI: 10.1128/aac.02223-20] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2020] [Accepted: 01/14/2021] [Indexed: 11/20/2022] Open
Abstract
When severe malaria is suspected in children, the WHO recommends pretreatment with a single rectal dose of artesunate before referral to an appropriate facility. This was an individually randomized, open-label, 2-arm, crossover clinical trial in 82 Congolese children with severe falciparum malaria to characterize the pharmacokinetics of rectal artesunate. At admission, children received a single dose of rectal artesunate (10 mg/kg of body weight) followed 12 h later by intravenous artesunate (2.4 mg/kg) or the reverse order. All children also received standard doses of intravenous quinine. Artesunate and dihydroartemisinin were measured at 11 fixed intervals, following 0- and 12-h drug administrations. Clinical, laboratory, and parasitological parameters were measured. After rectal artesunate, artesunate and dihydroartemisinin showed large interindividual variability (peak concentrations of dihydroartemisinin ranged from 5.63 to 8,090 nM). The majority of patients, however, reached previously suggested in vivo IC50 and IC90 values (98.7% and 92.5%, respectively) of combined concentrations of artesunate and dihydroartemisinin between 15 and 30 min after drug administration. The median (interquartile range [IQR]) time above IC50 and IC90 was 5.68 h (2.90 to 6.08) and 2.74 h (1.52 to 3.75), respectively. The absolute rectal bioavailability (IQR) was 25.6% (11.7 to 54.5) for artesunate and 19.8% (10.3 to 35.3) for dihydroartemisinin. The initial 12-h parasite reduction ratio was comparable between rectal and intravenous artesunate: median (IQR), 84.3% (50.0 to 95.4) versus 69.2% (45.7 to 93.6), respectively (P = 0.49). Despite large interindividual variability, rectal artesunate can initiate and sustain rapid parasiticidal activity in most children with severe falciparum malaria while they are transferred to a facility where parenteral artesunate is available. (This study has been registered at ClinicalTrials.gov under identifier NCT02492178.).
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Affiliation(s)
- Caterina Fanello
- Centre for Tropical Medicine and Global Health, Nuffield Department of Medicine, University of Oxford, Oxford, United Kingdom
- Mahidol-Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand
| | - Richard M Hoglund
- Centre for Tropical Medicine and Global Health, Nuffield Department of Medicine, University of Oxford, Oxford, United Kingdom
- Mahidol-Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand
| | - Sue J Lee
- Centre for Tropical Medicine and Global Health, Nuffield Department of Medicine, University of Oxford, Oxford, United Kingdom
- Mahidol-Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand
| | - Daddy Kayembe
- Kinshasa School of Public Health, University of Kinshasa, Kinshasa, Democratic Republic of Congo
| | - Pauline Ndjowo
- Kinshasa School of Public Health, University of Kinshasa, Kinshasa, Democratic Republic of Congo
| | - Charlie Kabedi
- Kinshasa School of Public Health, University of Kinshasa, Kinshasa, Democratic Republic of Congo
| | - Benjamin B Badjanga
- Kinshasa School of Public Health, University of Kinshasa, Kinshasa, Democratic Republic of Congo
| | - Phettree Niamyim
- Mahidol-Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand
| | - Joel Tarning
- Centre for Tropical Medicine and Global Health, Nuffield Department of Medicine, University of Oxford, Oxford, United Kingdom
- Mahidol-Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand
| | - Charles Woodrow
- Centre for Tropical Medicine and Global Health, Nuffield Department of Medicine, University of Oxford, Oxford, United Kingdom
- Mahidol-Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand
| | - Melba Gomes
- World Health Organization, Geneva, Switzerland
| | - Nick P Day
- Centre for Tropical Medicine and Global Health, Nuffield Department of Medicine, University of Oxford, Oxford, United Kingdom
- Mahidol-Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand
| | - Nicholas J White
- Centre for Tropical Medicine and Global Health, Nuffield Department of Medicine, University of Oxford, Oxford, United Kingdom
- Mahidol-Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand
| | - Marie A Onyamboko
- Kinshasa School of Public Health, University of Kinshasa, Kinshasa, Democratic Republic of Congo
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10
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Bai G, Gao Y, Liu S, Shui S, Liu G. pH-dependent rearrangement determines the iron-activation and antitumor activity of artemisinins. Free Radic Biol Med 2021; 163:234-242. [PMID: 33359684 DOI: 10.1016/j.freeradbiomed.2020.12.024] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/17/2020] [Revised: 12/02/2020] [Accepted: 12/07/2020] [Indexed: 02/03/2023]
Abstract
The action mechanisms of artemisinins remains elusive for decades, and one long-standing question is whether the indispensable peroxide group is activated by iron or heme. Although heme usually reacts faster with artemisinins than iron does, we have found that rearrangement of dihydroartemisinin (DHA) into monoketo-aldehyde-peroxyhemiacetal (MKA) under physiological conditions can significantly enhance its reaction towards iron. The rearrangement is pH-dependent and the derived MKA is identified by LC-MS in the cellular metabolites of DHA in cancer cells. MKA reacts quickly with ferrous irons to afford reactive carbon-centered radicals and can inhibit enzyme activities in vitro. Moreover, MKA oxidizes ferrous irons to ferric irons, which may explain the effect of DHA on decreasing cellular labile iron pool (LIP). Both addition of exogenous iron and increase in LIP via triggering ferroptosis can enhance the cytotoxicity of DHA against cancer cells. While artesunate (ATS) can also decompose to MKA after hydrolyzing into DHA, the other artemisinins of lower antitumor activity, e.g. artemisinin (ART), artemether (ATM) and arteether (ATE), exhibit negligible hydrolysis and rearrangement under the same conditions. Our study reveals the vital role of molecular rearrangement to the activation and activity of artemisinins and provides a new strategy for designing antitumor molecules containing endoperoxide group.
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Affiliation(s)
- Guangcan Bai
- State Key Laboratory of Natural and Biomimetic Drugs, School of Pharmaceutical Sciences, Peking University, Beijing, 100191, China
| | - Yibo Gao
- State Key Laboratory of Natural and Biomimetic Drugs, School of Pharmaceutical Sciences, Peking University, Beijing, 100191, China
| | - Sijin Liu
- State Key Laboratory of Natural and Biomimetic Drugs, School of Pharmaceutical Sciences, Peking University, Beijing, 100191, China
| | - Sufang Shui
- State Key Laboratory of Natural and Biomimetic Drugs, School of Pharmaceutical Sciences, Peking University, Beijing, 100191, China
| | - Guoquan Liu
- State Key Laboratory of Natural and Biomimetic Drugs, School of Pharmaceutical Sciences, Peking University, Beijing, 100191, China.
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11
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Microscopic and Submicroscopic Asymptomatic Plasmodium falciparum Infections in Ghanaian Children and Protection against Febrile Malaria. Infect Immun 2020; 88:IAI.00125-20. [PMID: 32719157 PMCID: PMC7504941 DOI: 10.1128/iai.00125-20] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2020] [Accepted: 07/20/2020] [Indexed: 11/20/2022] Open
Abstract
Naturally acquired immunity to Plasmodium falciparum malaria is thought to be nonsterile and sustained by persistence of low-level parasitemia. This study assessed the association between baseline microscopic and submicroscopic asymptomatic P. falciparum infections and antimalarial antibody levels and whether these parasitemia modify protective associations between antibody levels and malaria in Ghanaian children. Healthy children (N = 973, aged 0.5 to 12 years) were recruited into a 50-week longitudinal malaria cohort study from January 2016 to January 2017. Baseline asymptomatic parasitemia were determined by microscopy (microscopic parasitemia) and PCR (submicroscopic parasitemia), and antibody levels against crude schizont antigens were measured by enzyme-limited immunosorbent assay (ELISA). Antibody levels, parasite diversity, and risk of malaria in the ensuing transmission season were compared among children who had baseline asymptomatic microscopic or submicroscopic or no P. falciparum infections. Of the 99 asymptomatic baseline infections, 46 (46.5%) were microscopic and 53 (53.5%), submicroscopic. Cox regression analysis adjusting for age group, sex and community found a strong association between both baseline microscopic (hazard ratio [HR] = 0.36, 95% confidence interval [95% CI] = 0.21 to 0.63; P < 0.001) and submicroscopic (HR = 0.22, 95% CI = 0.11 to 0.44; P < 0.001) asymptomatic parasitemia and a reduced risk of febrile malaria compared to those who were uninfected at baseline. Baseline asymptomatic submicroscopic parasitemia had a significant effect on associations between antischizont antibodies and protection against febrile malaria (P < 0.001; likelihood ratio test). The study found both baseline P. falciparum asymptomatic microscopic and more strongly submicroscopic infections to be associated with protection against febrile malaria in the ensuing transmission season. This could have important implications for malaria seroepidemiological studies and vaccine trials.
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de Carvalho LP, Kreidenweiss A, Held J. The preclinical discovery and development of rectal artesunate for the treatment of malaria in young children: a review of the evidence. Expert Opin Drug Discov 2020; 16:13-22. [PMID: 32921162 DOI: 10.1080/17460441.2020.1804357] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
INTRODUCTION Plasmodium falciparum, the deadliest malaria parasite, kills hundreds of thousands of people per year, mainly young children in Sub-Saharan Africa. Artesunate suppositories are recommended as pre-referral malaria treatment in remote endemic areas for severely ill children to prevent progression of the disease and to provide extra time for patients until the definitive severe malaria treatment can be administered. AREAS COVERED The authors provide an overview of the discovery of artesunate and its different formulations focusing on rectal administration, summarizing key studies concerning the pharmacokinetic, pharmacodynamic, safety, tolerability and efficacy of rectal artesunate leading to WHO recommendation and market authorization in Africa. In addition, studies on acceptance and adherence to rectal artesunate administration and the post-launch status are also covered. EXPERT OPINION Efforts by ministries of health in malaria endemic countries together with international health organizations should establish and enforce guidelines to ensure the correct use of artesunate suppositories only as pre-referral medication in presumed severe malaria cases to minimize the risk of abuse as a monotherapy for treatment of uncomplicated malaria. The priority is to not jeopardize the efficacy of artesunate and to prevent resistance development against this valuable drug class in Africa.
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Affiliation(s)
| | - Andrea Kreidenweiss
- Institute of Tropical Medicine, University of Tübingen , Tübingen, Germany.,Centre De Recherches Médicales De Lambaréné , Lambaréné, Gabon
| | - Jana Held
- Institute of Tropical Medicine, University of Tübingen , Tübingen, Germany.,Centre De Recherches Médicales De Lambaréné , Lambaréné, Gabon
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Angus BJ. An evaluation of rectal artesunate for the pre-hospital management of severe malaria. Expert Opin Pharmacother 2020; 21:645-651. [PMID: 31990585 DOI: 10.1080/14656566.2020.1718108] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
Abstract
INTRODUCTION Severe falciparum malaria stills accounts for around half a million childhood deaths per year in sub-Saharan Africa. Prompt treatment of sick children close to home starting with artesunate given rectally by appropriately trained people can be lifesaving. AREAS COVERED Rectal artesunate (RAS) has been developed for use in the WHO approved strategy of pre-referral intervention. This review covers the formulation, pharmacokinetics, safety, efficacy, and implementation of this drug. There is little RCT evidence and the only RCT has been controversial. It is unlikely that there will be further randomized studies in the field. There is a concern that the administration of a single dose of artesunate without adequate follow up therapy may encourage the emergence of artemisinin resistance. EXPERT OPINION Artesunate is an essential drug and RAS is a very useful, potentially lifesaving formulation designed to be quickly administered in remote areas to severely unwell children by non-medical personnel. However, its use needs to be monitored and onward referral for definitive antimalarial treatment ensured.
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Affiliation(s)
- Brian John Angus
- Nuffield Department of Medicine, Oxford University, The John Radcliffe , Oxford, UK
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Karbwang J, Na‐Bangchang K. The Role of Clinical Pharmacology in Chemotherapy of Multidrug‐Resistant
Plasmodium falciparum. J Clin Pharmacol 2020; 60:830-847. [DOI: 10.1002/jcph.1589] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2019] [Accepted: 01/21/2020] [Indexed: 01/02/2023]
Affiliation(s)
- Juntra Karbwang
- Graduate Program in Bioclinical SciencesChulabhorn International College of MedicineThammasat University (Rangsit Campus) Pathumthani Thailand
- Center of Excellence in Pharmacology and Molecular Biology of Malaria and CholangiocarcinomaThammasat University (Rangsit Campus) Pathumthani Thailand
- Drug Discovery and Development Center, Office of Advanced Science and TechnologyThammasat University (Rangsit Campus) Pathumthani Thailand
- Department of Clinical Product developmentNagasaki Institute of Tropical MedicineNagasaki University Nagasaki Japan
| | - Kesara Na‐Bangchang
- Graduate Program in Bioclinical SciencesChulabhorn International College of MedicineThammasat University (Rangsit Campus) Pathumthani Thailand
- Center of Excellence in Pharmacology and Molecular Biology of Malaria and CholangiocarcinomaThammasat University (Rangsit Campus) Pathumthani Thailand
- Drug Discovery and Development Center, Office of Advanced Science and TechnologyThammasat University (Rangsit Campus) Pathumthani Thailand
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15
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Xie Y, Liu H, Sun Y, Xing J. The gender-related variability in the pharmacokinetics and antiplasmodial activity of naphthoquine in rodents. Malar J 2020; 19:71. [PMID: 32054478 PMCID: PMC7020547 DOI: 10.1186/s12936-020-3153-8] [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: 11/22/2019] [Accepted: 02/05/2020] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Naphthoquine (NQ) is a suitable partner anti-malarial for the artemisinin-based combination therapy (ACT), which is recommended to be taken orally as a single-dose regimen. The metabolism of NQ was mainly mediated by CYP2D6, which is well-known to show gender-specific differences in its expression. In spite of its clinical use, there is limited information on the pharmacokinetics of NQ, and no data are available for females. In this study, the effect of gender on the pharmacokinetics and antiplasmodial efficacy of NQ in rodents was evaluated. The underlying factors leading to the potential gender difference, i.e., plasma protein binding and metabolic clearance, were also evaluated. METHODS The pharmacokinetic profiles of NQ were investigated in healthy male or female rats after a single oral administration of NQ. The antiplasmodial efficacy of NQ was studied in male or female mice infected with Plasmodium yoelii. The recrudescence and survival time of infected mice were also recorded after drug treatment. Plasma protein binding of NQ was determined in pooled plasma collected from male or female mice, rat or human. In vitro metabolism experiments were performed in the liver microsomes of male or female mice, rat or human. RESULTS The results showed that the gender of rats did not affect NQ exposure (AUC0-t and Cmax) significantly (P > 0.05). However, a significant (P < 0.05) longer t1/2 was found for NQ in male rats (192.1 ± 47.7), compared with female rats (143.9 ± 27.1). Slightly higher but not significant (P > 0.05) antiplasmodial activity was found for NQ in male mice (ED90, 1.10 mg/kg) infected with P. yoelii, compared with female mice (ED90, 1.67 mg/kg). The binding rates of NQ to plasma protein were similar in males and females. There was no metabolic difference for NQ in male and female mice, rat or human liver microsomes. CONCLUSIONS These results indicated that the pharmacokinetic profiles of NQ were similar between male and female rats, except for a longer t1/2 in male rats. The difference was not associated with plasma protein binding or hepatic metabolic clearance. Equivalent antiplasmodial activity was found for NQ in male and female mice infected with P. yoelii. This study will be helpful for the rational design of clinical trials for NQ.
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Affiliation(s)
- Yuewu Xie
- School of Pharmaceutical Science, Shandong University, 44 West Wenhua Road, Jinan, 250012, People's Republic of China
| | - Huixiang Liu
- School of Pharmaceutical Science, Shandong University, 44 West Wenhua Road, Jinan, 250012, People's Republic of China
| | - Yanhong Sun
- School of Pharmaceutical Science, Shandong University, 44 West Wenhua Road, Jinan, 250012, People's Republic of China
| | - Jie Xing
- School of Pharmaceutical Science, Shandong University, 44 West Wenhua Road, Jinan, 250012, People's Republic of China.
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Plewes K, Leopold SJ, Kingston HWF, Dondorp AM. Malaria: What's New in the Management of Malaria? Infect Dis Clin North Am 2019; 33:39-60. [PMID: 30712767 DOI: 10.1016/j.idc.2018.10.002] [Citation(s) in RCA: 39] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
The global burden of malaria remains high, with 216 million cases causing 445,000 deaths in 2016 despite first-line treatment with artemisinin-based combination therapy. Decreasing transmission in Africa shifts the risk for severe malaria to older age groups as premunition wanes. Prompt diagnosis and treatment with intravenous artesunate in addition to appropriate supportive management are critical to reduce deaths from severe malaria. Effective individual management is challenging in settings with limited resources for higher-level care. Adjunctive therapies targeting the underlying pathophysiological pathways have the potential to reduce mortality. Resistance to artemisinin derivatives and their partner drugs threaten malaria management and control.
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Affiliation(s)
- Katherine Plewes
- Malaria Department, Mahidol Oxford Research Unit, Faculty of Tropical Medicine, Mahidol University, 3/F 60th, Anniversary Chalermprakiat Building, 420/6 Rajvithi Road, Bangkok 10400, Thailand; Department of Medicine, University of British Columbia, Vancouver General Hospital, 452D Heather Pavilion East, 2733 Heather Street, Vancouver, British Columbia V5Z 3J5, Canada
| | - Stije J Leopold
- Malaria Department, Mahidol Oxford Research Unit, Faculty of Tropical Medicine, Mahidol University, 3/F 60th, Anniversary Chalermprakiat Building, 420/6 Rajvithi Road, Bangkok 10400, Thailand
| | - Hugh W F Kingston
- Nuffield Department of Clinical Medicine, University of Oxford, Old Road Campus, Headington, Oxford OX3 7BN, UK; Malaria Department, Mahidol Oxford Research Unit, Faculty of Tropical Medicine, Mahidol University, 3/F 60th, Anniversary Chalermprakiat Building, 420/6 Rajvithi Road, Bangkok 10400, Thailand
| | - Arjen M Dondorp
- Nuffield Department of Clinical Medicine, University of Oxford, Old Road Campus, Headington, Oxford OX3 7BN, UK; Mahidol-Oxford Tropical Medicine Research Unit (MORU), Faculty of Tropical Medicine, Mahidol University, 3/F 60th, Anniversary Chalermprakiat Building, 420/6 Rajvithi Road, Bangkok 10400, Thailand.
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Systematic review of artesunate pharmacokinetics: Implication for treatment of resistant malaria. Int J Infect Dis 2019; 89:30-44. [PMID: 31491558 DOI: 10.1016/j.ijid.2019.08.030] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2019] [Revised: 08/23/2019] [Accepted: 08/28/2019] [Indexed: 11/21/2022] Open
Abstract
BACKGROUND Artesunate (ART) is an artemisinin derivative used as monotherapy for the treatment of severe malaria and in combination with a partner drug for non-severe malaria. Resistance of malaria parasites to artemisinins have emerged in Southeast Asia. Adjustment of drug regimen may be an option to prevent therapeutic failures considering the relative favourable safety profile of ART high doses. METHODS For that purpose, a systematic review was done using PubMed, Scopus and Web of Science databases. All studies on ART and DHA pharmacokinetic post-administration of artesunate in human patients or volunteers were included. The Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) checklist 2009 was used. FINDINGS Fifty studies exploring oral, intravenous, rectal, and intramuscular route (1470 persons, volunteers and patients) were included. Correlations between artesunate doses and Cmax or AUC0-∞ of dihydroartemisinin (DHA) and DHA+ART were evaluated. This correlation was good (R2>0.9) using intravenous (IV) route. DHA and ART+DHA average concentrations (Cav) were well above estimated in vivo half-maximal effective concentration (EC50) for intravenous route, but this was not the case for oral route. INTERPRETATION The favorable Cav/EC50 ratio for IV route provides evidence that IV ART will remain efficient even in the case of increased resistance level, whereas for the oral route, a two-fold increase in EC50 may lead to therapeutic failures, thus providing a rationale for oral dose escalation. Considering the inter-individual variability of ART pharmacokinetic, Therapeutic Drug Monitoring through antimalarial stewardship activities is needed to optimize drug exposure and avoid resistance development.
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18
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Influence Factors of the Pharmacokinetics of Herbal Resourced Compounds in Clinical Practice. EVIDENCE-BASED COMPLEMENTARY AND ALTERNATIVE MEDICINE 2019; 2019:1983780. [PMID: 30949215 PMCID: PMC6425497 DOI: 10.1155/2019/1983780] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Received: 11/14/2018] [Accepted: 01/15/2019] [Indexed: 12/12/2022]
Abstract
Herbal medicines have been used to prevent and cure diseases in eastern countries for thousands of years. In recent decades, these phytotherapies are becoming more and more popular in the West. As being nature-derived is the essential attribute of herbal medicines, people believe that taking them for diseases treatment is safe enough and has no side-effects. However, the efficacy of herbal resourced compounds (HRC) depends on the multiple constituents absorbed in the body and their pharmacokinetics. Thus, many factors will influence the clinical practice of HRC, i.e., their absorption, distribution, metabolism, and excretion (ADME). Among these factors, herb-drug interaction has been widely discussed, as these compounds may share the same drug-metabolizing enzymes and drug transporters. Meanwhile there are many other potential factors that can also change the ADME of HRC, including herb pretreatment, herb-herb interactions, pathological status, gender, age of patient, and chemical and physical modification of certain ingredients. With the aim of ensuring the efficacy of HRC and minimizing their clinical risks, this review provides and discusses the influence factors and artificial improvement of the pharmacokinetics of HRC.
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19
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Kajubi R, Huang L, Were M, Kiconco S, Li F, Marzan F, Gingrich D, Nyunt MM, Ssebuliba J, Mwebaza N, Aweeka FT, Parikh S. Parasite Clearance and Artemether Pharmacokinetics Parameters Over the Course of Artemether-Lumefantrine Treatment for Malaria in Human Immunodeficiency Virus (HIV)-Infected and HIV-Uninfected Ugandan Children. Open Forum Infect Dis 2016; 3:ofw217. [PMID: 28018925 PMCID: PMC5170492 DOI: 10.1093/ofid/ofw217] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2016] [Accepted: 10/11/2016] [Indexed: 11/13/2022] Open
Abstract
Background. Artemisinins are primarily responsible for initial parasite clearance. Antimalarial pharmacokinetics (PK), human immunodeficiency virus (HIV) infection, and antiretroviral therapy have been shown to impact treatment outcomes, although their impact on early parasite clearance in children has not been well characterized. Methods. Parasite clearance parameters were generated from twice-daily blood smears in HIV-infected and HIV-uninfected Ugandan children treated with artemether-lumefantrine (AL). Artemether and dihydroartemisinin (DHA) area-under-the-curve from 0–8 hours (AUC0-8hr) after the 1st AL dose was compared with AUC0-8hr after the last (6th) dose in a concurrently enrolled cohort. The association between post-1st dose artemisinin AUC0-8hr and parasite clearance was assessed. Results. Parasite clearance was longer in HIV-infected versus HIV-uninfected children (median, 3.5 vs 2.8 hours; P = .003). Artemether AUC0-8hr was 3- to 4-fold lower after the 6th dose versus the 1st dose of AL in HIV-infected children on nevirapine- or lopinavir/ritionavir-based regimens and in HIV-uninfected children (P ≤ .002, 1st vs 6th-dose comparisons). Children on efavirenz exhibited combined post-1st dose artemether/DHA exposure that was significantly lower than those on lopinavir/ritonavir and HIV-uninfected children. Multiple regression analysis supported that the effect of artemether/DHA exposure on parasite clearance was significantly moderated by HIV status. Conclusions. Parasite clearance rates remain rapid in Uganda and were not found to associate with PK exposure. However, significant decreases in artemisinin PK with repeated dosing in nearly all children, coupled with small, but significant increase in parasite clearance half-life in those with HIV, may have important implications for AL efficacy, particularly because reports of artemisinin resistance are increasing.
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Affiliation(s)
- Richard Kajubi
- Infectious Disease Research Collaboration, Kampala, Uganda
| | - Liusheng Huang
- University of California-San Francisco, San Francisco General Hospital
| | - Moses Were
- Infectious Disease Research Collaboration, Kampala, Uganda
| | - Sylvia Kiconco
- University of California-San Francisco, San Francisco General Hospital
| | - Fangyong Li
- Yale University School of Public Health and Medicine , New Haven, Connecticut
| | - Florence Marzan
- University of California-San Francisco, San Francisco General Hospital
| | - David Gingrich
- University of California-San Francisco, San Francisco General Hospital
| | - Myaing M Nyunt
- Institute for Global Health, University of Maryland Baltimore School of Medicine
| | | | - Norah Mwebaza
- Infectious Disease Research Collaboration, Kampala, Uganda
| | | | - Sunil Parikh
- Yale University School of Public Health and Medicine , New Haven, Connecticut
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20
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Kloprogge F, McGready R, Phyo AP, Rijken MJ, Hanpithakpon W, Than HH, Hlaing N, Zin NT, Day NPJ, White NJ, Nosten F, Tarning J. Opposite malaria and pregnancy effect on oral bioavailability of artesunate - a population pharmacokinetic evaluation. Br J Clin Pharmacol 2015; 80:642-53. [PMID: 25877779 PMCID: PMC4594700 DOI: 10.1111/bcp.12660] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2014] [Revised: 03/24/2015] [Accepted: 04/01/2015] [Indexed: 11/27/2022] Open
Abstract
Aim The aim was to compare the pharmacokinetic properties of artesunate and dihydroartemisinin in the same women: i) pregnant with acute uncomplicated malaria on day 1 and 2, ii) pregnant with convalescent malaria on day 7 and iii) in a healthy state 3 months post-partum on day 1, 2 and 7. Methods Non-linear mixed-effects modelling was used to compare plasma concentration–time profiles of artesunate and dihydroartemisinin over 7 days of treatment following oral and intravenous artesunate administration to pregnant women with uncomplicated Plasmodium falciparum malaria during their second or third trimesters of pregnancy. The same women were restudied 3 months after delivery when fully recovered. Non-compartmental results of the same study have been published previously. Results Twenty pregnant patients on the Thailand-Myanmar border were studied and 15 volunteered to be restudied 3 months post-partum. Malaria and pregnancy had no effect on the pharmacokinetic properties of artesunate or dihydroartemisinin after intravenous artesunate administration. However, malaria and pregnancy had opposite effects on the absorption of orally administered artesunate. Malaria increased the absolute oral bioavailability of artesunate by 87%, presumably by inhibiting first pass effect, whereas pregnancy decreased oral bioavailability by 23%. Conclusions The population pharmacokinetic analysis demonstrated opposite effects of malaria and pregnancy on the bioavailability of orally administered artesunate. Lower drug exposures during the second and third trimesters of pregnancy may contribute to lower cure rates and thus the development of drug resistance. Dose optimization studies are required for artesunate containing artemisinin-based combination therapies (ACTs) in later pregnancy.
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Affiliation(s)
- Frank Kloprogge
- Centre for Tropical Medicine and Global Health, Nuffield Department of Medicine, University of Oxford, United Kingdom.,Mahidol-Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Bangkok
| | - Rose McGready
- Centre for Tropical Medicine and Global Health, Nuffield Department of Medicine, University of Oxford, United Kingdom.,Mahidol-Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Bangkok.,Shoklo Malaria Research Unit, Mahidol-Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Mae Sot, Thailand
| | - Aung Pyae Phyo
- Shoklo Malaria Research Unit, Mahidol-Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Mae Sot, Thailand
| | - Marcus J Rijken
- Shoklo Malaria Research Unit, Mahidol-Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Mae Sot, Thailand
| | - Warunee Hanpithakpon
- Mahidol-Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Bangkok
| | - Hla Hla Than
- Shoklo Malaria Research Unit, Mahidol-Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Mae Sot, Thailand
| | - Nathar Hlaing
- Shoklo Malaria Research Unit, Mahidol-Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Mae Sot, Thailand
| | - Naw Thida Zin
- Shoklo Malaria Research Unit, Mahidol-Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Mae Sot, Thailand
| | - Nicholas P J Day
- Centre for Tropical Medicine and Global Health, Nuffield Department of Medicine, University of Oxford, United Kingdom.,Mahidol-Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Bangkok
| | - Nicholas J White
- Centre for Tropical Medicine and Global Health, Nuffield Department of Medicine, University of Oxford, United Kingdom.,Mahidol-Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Bangkok
| | - François Nosten
- Centre for Tropical Medicine and Global Health, Nuffield Department of Medicine, University of Oxford, United Kingdom.,Mahidol-Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Bangkok.,Shoklo Malaria Research Unit, Mahidol-Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Mae Sot, Thailand
| | - Joel Tarning
- Centre for Tropical Medicine and Global Health, Nuffield Department of Medicine, University of Oxford, United Kingdom.,Mahidol-Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Bangkok
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Zaloumis SG, Tarning J, Krishna S, Price RN, White NJ, Davis TME, McCaw JM, Olliaro P, Maude RJ, Kremsner P, Dondorp A, Gomes M, Barnes K, Simpson JA. Population pharmacokinetics of intravenous artesunate: a pooled analysis of individual data from patients with severe malaria. CPT-PHARMACOMETRICS & SYSTEMS PHARMACOLOGY 2014; 3:e145. [PMID: 25372510 PMCID: PMC4259998 DOI: 10.1038/psp.2014.43] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/03/2014] [Accepted: 08/28/2014] [Indexed: 11/09/2022]
Abstract
There are ~660,000 deaths from severe malaria each year. Intravenous artesunate (i.v. ARS) is the first-line treatment in adults and children. To optimize the dosing regimen of i.v. ARS, the largest pooled population pharmacokinetic study to date of the active metabolite dihydroartemisinin (DHA) was performed. The pooled dataset consisted of 71 adults and 195 children with severe malaria, with a mixture of sparse and rich sampling within the first 12 h after drug administration. A one-compartment model described the population pharmacokinetics of DHA adequately. Body weight had the greatest impact on DHA pharmacokinetics, resulting in lower DHA exposure for smaller children (6–10 kg) than adults. Post hoc estimates of DHA exposure were not significantly associated with parasitological outcomes. Comparable DHA exposure in smaller children and adults after i.v. ARS was achieved under a dose modification for intramuscular ARS proposed in a separate analysis of children.
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Affiliation(s)
- S G Zaloumis
- Centre for Epidemiology and Biostatistics, Melbourne School of Population and Global Health, University of Melbourne, Melbourne, Australia
| | - J Tarning
- Mahidol-Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand
| | - S Krishna
- Institute for Infection and Immunity, St. George's, University of London, London, UK
| | - R N Price
- Centre for Clinical Vaccinology and Tropical Medicine, Nuffield Department of Medicine, University of Oxford, Oxford, UK
| | - N J White
- 1] Mahidol-Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand [2] Centre for Tropical Medicine, Nuffield Department of Clinical Medicine, University of Oxford, Oxford, UK
| | - T M E Davis
- School of Medicine and Pharmacology, Fremantle Hospital, University of Western Australia, Fremantle, Australia
| | - J M McCaw
- Centre for Epidemiology and Biostatistics, Melbourne School of Population and Global Health, University of Melbourne, Melbourne, Australia
| | - P Olliaro
- 1] Centre for Tropical Medicine, Nuffield Department of Clinical Medicine, University of Oxford, Oxford, UK [2] World Health Organization, Genève, Switzerland
| | - R J Maude
- 1] Mahidol-Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand [2] Centre for Tropical Medicine, Nuffield Department of Medicine, University of Oxford, Oxford, UK
| | - P Kremsner
- 1] Medical Research Unit, Albert Schweitzer Hospital, Lambaréné, Gabon [2] Institute for Tropical Medicine, Department of Parasitology, University of Tübingen, Tübingen, Germany
| | - A Dondorp
- 1] Centre for Tropical Medicine, Nuffield Department of Clinical Medicine, University of Oxford, Oxford, UK [2] Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand
| | - M Gomes
- World Health Organization, Genève, Switzerland
| | - K Barnes
- Division of Clinical Pharmacology, Department of Medicine, University of Cape Town, Cape Town, South Africa
| | - J A Simpson
- Centre for Epidemiology and Biostatistics, Melbourne School of Population and Global Health, University of Melbourne, Melbourne, Australia
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23
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Matar KM, Awad AI, Elamin SB. Pharmacokinetics of artesunate alone and in combination with sulfadoxine/pyrimethamine in healthy Sudanese volunteers. Am J Trop Med Hyg 2014; 90:1087-93. [PMID: 24615137 DOI: 10.4269/ajtmh.13-0283] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
Abstract
Artesunate (AS) in combination with sulfadoxine/pyrimethamine (SP) is the first-line therapy for management of uncomplicated Plasmodium falciparum malaria in Sudan. The objective of this study was to assess the potential impact of SP on the pharmacokinetics of AS and its active metabolite, dihydroartemisinin (DHA), in healthy adults. A single-dose, randomized, open-label, crossover study design with a washout period of three weeks was performed with 16 volunteers. After oral administration of AS alone or in combination with SP, Tmax values of AS and DHA were significantly prolonged in the combination group (P < 0.05). However, there was no significant effect on the other pharmacokinetic parameters (P > 0.05). The t1/2 values of AS and DHA were significantly higher in females than in males (P < 0.05). The present findings suggest that co-administration of SP with AS has no clinically relevant impact on the pharmacokinetics of AS or DHA in healthy persons.
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Affiliation(s)
- Kamal M Matar
- Department of Pharmacology and Therapeutics, and Department of Pharmacy Practice, Faculty of Pharmacy, Kuwait University, Kuwait; National Medicines and Poisons Board, Khartoum, Sudan
| | - Abdelmoneim I Awad
- Department of Pharmacology and Therapeutics, and Department of Pharmacy Practice, Faculty of Pharmacy, Kuwait University, Kuwait; National Medicines and Poisons Board, Khartoum, Sudan
| | - Sakina B Elamin
- Department of Pharmacology and Therapeutics, and Department of Pharmacy Practice, Faculty of Pharmacy, Kuwait University, Kuwait; National Medicines and Poisons Board, Khartoum, Sudan
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Pharmacokinetic and pharmacodynamic considerations in antimalarial dose optimization. Antimicrob Agents Chemother 2013; 57:5792-807. [PMID: 24002099 PMCID: PMC3837842 DOI: 10.1128/aac.00287-13] [Citation(s) in RCA: 72] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023] Open
Abstract
Antimalarial drugs have usually been first deployed in areas of malaria endemicity at doses which were too low, particularly for high-risk groups such as young children and pregnant women. This may accelerate the emergence and spread of resistance, thereby shortening the useful life of the drug, but it is an inevitable consequence of the current imprecise method of dose finding. An alternative approach to dose finding is suggested in which phase 2 studies concentrate initially on pharmacokinetic-pharmacodynamic (PK-PD) characterization and in vivo calibration of in vitro susceptibility information. PD assessment is facilitated in malaria because serial parasite densities are readily assessed by microscopy, and at low densities by quantitative PCR, so that initial therapeutic responses can be quantitated accurately. If the in vivo MIC could be characterized early in phase 2 studies, it would provide a sound basis for the choice of dose in all target populations in subsequent combination treatments. Population PK assessments in phase 2b and phase 3 studies which characterize PK differences between different age groups, clinical disease states, and human populations can then be combined with the PK-PD observations to provide a sound evidence base for dose recommendations in different target groups.
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Population pharmacokinetics of intramuscular artesunate in African children with severe malaria: implications for a practical dosing regimen. Clin Pharmacol Ther 2013; 93:443-50. [PMID: 23511715 PMCID: PMC3630454 DOI: 10.1038/clpt.2013.26] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Parenteral artesunate (ARS) is the drug of choice for the treatment of severe malaria. Pharmacokinetics data on intramuscular ARS are limited with respect to the main treatment group that carries the highest mortality, namely, critically ill children with severe malaria. A population pharmacokinetic study of ARS and dihydroartemisinin (DHA) was conducted from sparse sampling in 70 Tanzanian children of ages 6 months to 11 years. All the children had been admitted with severe falciparum malaria and were treated with intramuscular ARS (2.4 mg/kg at 0, 12, and 24 h). Venous plasma concentration-time profiles were characterized using nonlinear mixed-effects modeling (NONMEM). A one-compartment disposition model accurately described first-dose population pharmacokinetics of ARS and DHA. Body weight significantly affected clearance and apparent volume of distribution (P < 0.001), resulting in lower ARS and DHA exposure levels in smaller children. An adapted dosing regimen including a practical dosing table per weight band is proposed for young children based on the pharmacokinetic model.
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Zhu F, Du F, Li X, Xing J. An investigation of the auto-induction of and gender-related variability in the pharmacokinetics of dihydroartemisinin in the rat. Malar J 2012; 11:379. [PMID: 23171067 PMCID: PMC3511063 DOI: 10.1186/1475-2875-11-379] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2012] [Accepted: 10/30/2012] [Indexed: 01/27/2023] Open
Abstract
Background Artemisinin (QHS) and its derivatives dihydroartemisinin (DHA), artemether and artesunate have become the first-line anti-malarials in areas of multidrug resistance. Declining plasma concentrations during the repeated dosing have been reported for QHS, artemether and less convincingly for artesunate (ARS). However, there is limited information on whether the concentrations of their active metabolite DHA and its subsequent metabolites increased after multiple drug administrations. This study was designed to evaluate the potential auto-induction metabolism of DHA in animal species. The sex-specific effect on the pharmacokinetic profiles of DHA and its metabolites was studied. The pharmacokinetics of ARS, the prodrug of DHA, and its phase I/II metabolites were also investigated. Methods Two groups of rats received a single oral dose of DHA or ARS, and another two groups of rats were given oral doses of DHA or ARS once daily for five consecutive days. Plasma samples were analyzed for DHA, ARS and their phase I/II metabolites, using a validated liquid chromatography tandem mass spectrometric (LC-MS) method. Results DHA, monohydroxylated DHA (M1) and the glucuronide of DHA (DHA-G) were detected in rat plasma after oral administration of DHA or ARS. Neither DHA nor its metabolites (M1 and DHA-G) changed significantly (P > 0.05) in AUC0-t after 5-day oral doses of DHA or ARS. Sex difference was observed for DHA and its metabolites (M1 and DHA-G), whereas its prodrug ARS did not show similar characteristics for the corresponding metabolites (DHA, M1 and DHA-G). Conclusions The results gave the direct evidence for the absence of auto-induction of phase I and phase II metabolism of DHA and ARS in rats. The sex effect existed for DHA but not for ARS, which could be caused by the sex-specific differences in absorption of DHA.
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Affiliation(s)
- Fanping Zhu
- School of Pharmaceutical Sciences, Shandong University, Jinan 250012, People's Republic of China
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27
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Abstract
Malaria chemotherapy is under constant threat from the emergence and spread of multidrug resistance of Plasmodium falciparum. Resistance has been observed to almost all currently used antimalarials. Some drugs are also limited by toxicity. A fundamental component of the strategy for malaria chemotherapy is based on prompt, effective and safe antimalarial drugs. To counter the threat of resistance of P. falciparum to existing monotherapeutic regimens, current malaria treatment is based principally on the artemisinin group of compounds, either as monotherapy or artemisinin-based combination therapies for treatment of both uncomplicated and severe falciparum malaria. Key advantages of artemisinins over the conventional antimalarials include their rapid and potent action, with good tolerability profiles. Their action also covers transmissible gametocytes, resulting in decreased disease transmission. Up to now there has been no prominent report of drug resistance to this group of compounds. Treatment of malaria in pregnant women requires special attention in light of limited treatment options caused by potential teratogenicity coupled with a paucity of safety data for the mother and fetus. Treatment of other malaria species is less problematic and chloroquine is still the drug of choice, although resistance of P. vivax to chloroquine has been reported. Multiple approaches to the identification of new antimalarial targets and promising antimalarial drugs are being pursued in order to cope with drug resistance.
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Affiliation(s)
- Kesara Na-Bangchang
- Faculty of Allied Health Sciences, Thammasat University (Rangsit Campus), Paholyothin Road, Klong Luang District, Pathumtanee 12121, Thailand.
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Kremsner PG, Taylor T, Issifou S, Kombila M, Chimalizeni Y, Kawaza K, Bouyou Akotet MK, Duscha M, Mordmüller B, Kösters K, Humberg A, Miller RS, Weina P, Duparc S, Möhrle J, Kun JFJ, Planche T, Teja-Isavadharm P, Simpson JA, Köhler C, Krishna S. A Simplified Intravenous Artesunate Regimen for Severe Malaria. J Infect Dis 2011; 205:312-9. [DOI: 10.1093/infdis/jir724] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
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Morris CA, Duparc S, Borghini-Fuhrer I, Jung D, Shin CS, Fleckenstein L. Review of the clinical pharmacokinetics of artesunate and its active metabolite dihydroartemisinin following intravenous, intramuscular, oral or rectal administration. Malar J 2011; 10:263. [PMID: 21914160 PMCID: PMC3180444 DOI: 10.1186/1475-2875-10-263] [Citation(s) in RCA: 140] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2011] [Accepted: 09/13/2011] [Indexed: 11/10/2022] Open
Abstract
Artesunate (AS) is a clinically versatile artemisinin derivative utilized for the treatment of mild to severe malaria infection. Given the therapeutic significance of AS and the necessity of appropriate AS dosing, substantial research has been performed investigating the pharmacokinetics of AS and its active metabolite dihydroartemisinin (DHA). In this article, a comprehensive review is presented of AS clinical pharmacokinetics following administration of AS by the intravenous (IV), intramuscular (IM), oral or rectal routes. Intravenous AS is associated with high initial AS concentrations which subsequently decline rapidly, with typical AS half-life estimates of less than 15 minutes. AS clearance and volume estimates average 2 - 3 L/kg/hr and 0.1 - 0.3 L/kg, respectively. DHA concentrations peak within 25 minutes post-dose, and DHA is eliminated with a half-life of 30 - 60 minutes. DHA clearance and volume average between 0.5 - 1.5 L/kg/hr and 0.5 - 1.0 L/kg, respectively. Compared to IV administration, IM administration produces lower peaks, longer half-life values, and higher volumes of distribution for AS, as well as delayed peaks for DHA; other parameters are generally similar due to the high bioavailability, assessed by exposure to DHA, associated with IM AS administration (> 86%). Similarly high bioavailability of DHA (> 80%) is associated with oral administration. Following oral AS, peak AS concentrations (Cmax) are achieved within one hour, and AS is eliminated with a half-life of 20 - 45 minutes. DHA Cmax values are observed within two hours post-dose; DHA half-life values average 0.5 - 1.5 hours. AUC values reported for AS are often substantially lower than those reported for DHA following oral AS administration. Rectal AS administration yields pharmacokinetic results similar to those obtained from oral administration, with the exceptions of delayed AS Cmax and longer AS half-life. Drug interaction studies conducted with oral AS suggest that AS does not appreciably alter the pharmacokinetics of atovaquone/proguanil, chlorproguanil/dapsone, or sulphadoxine/pyrimethamine, and mefloquine and pyronaridine do not alter the pharmacokinetics of DHA. Finally, there is evidence suggesting that the pharmacokinetics of AS and/or DHA following AS administration may be altered by pregnancy and by acute malaria infection, but further investigation would be required to define those alterations precisely.
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Affiliation(s)
- Carrie A Morris
- Pharmaceutical Sciences and Experimental Therapeutics, University of Iowa College of Pharmacy, 115 South Grand Avenue, Iowa City, IA 52242, USA
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Jamsen KM, Duffull SB, Tarning J, Lindegardh N, White NJ, Simpson JA. Optimal designs for population pharmacokinetic studies of oral artesunate in patients with uncomplicated falciparum malaria. Malar J 2011; 10:181. [PMID: 21722356 PMCID: PMC3155838 DOI: 10.1186/1475-2875-10-181] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2011] [Accepted: 07/01/2011] [Indexed: 01/18/2023] Open
Abstract
Background Currently, population pharmacokinetic (PK) studies of anti-malarial drugs are designed primarily by the logistical and ethical constraints of taking blood samples from patients, and the statistical models that are fitted to the data are not formally considered. This could lead to imprecise estimates of the target PK parameters, and/or designs insufficient to estimate all of the parameters. Optimal design methodology has been developed to determine blood sampling schedules that will yield precise parameter estimates within the practical constraints of sampling the study populations. In this work optimal design methods were used to determine sampling designs for typical future population PK studies of dihydroartemisinin, the principal biologically active metabolite of oral artesunate. Methods Optimal designs were derived using freely available software and were based on appropriate structural PK models from an analysis of data or the literature and key sampling constraints identified in a questionnaire sent to active malaria researchers (3-4 samples per patient, at least 15 minutes between samples). The derived optimal designs were then evaluated via simulation-estimation. Results The derived optimal sampling windows were 17 to 29 minutes, 30 to 57 minutes, 2.5 to 3.7 hours and 5.8 to 6.6 hours for non-pregnant adults; 16 to 29 minutes, 31 minutes to 1 hour, 2.0 to 3.4 hours and 5.5 to 6.6 hours for designs with non-pregnant adults and children and 35 to 59 minutes, 1.2 to 3.4 hours, 3.4 to 4.9 hours and 6.0 to 8.0 hours for pregnant women. The optimal designs resulted in acceptable precision of the PK parameters. Conclusions The proposed sampling designs in this paper are robust and efficient and should be considered in future PK studies of oral artesunate where only three or four blood samples can be collected.
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Affiliation(s)
- Kris M Jamsen
- Centre for Molecular, Environmental, Genetic and Analytic Epidemiology, School of Population Health, The University of Melbourne, Melbourne, Australia.
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Pharmacokinetic and pharmacodynamic characteristics of a new pediatric formulation of artemether-lumefantrine in African children with uncomplicated Plasmodium falciparum malaria. Antimicrob Agents Chemother 2011; 55:3994-9. [PMID: 21670177 DOI: 10.1128/aac.01115-10] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The pharmacokinetic and pharmacodynamic properties of a new pediatric formulation of artemether-lumefantrine, dispersible tablet, were determined within the context of a multicenter, randomized, parallel-group study. In an exploratory approach, we compared a new pediatric formulation with the tablet formulation administered crushed in the treatment of African children with uncomplicated Plasmodium falciparum malaria. Patients were randomized to 3 different dosing groups (weights of 5 to <15 kg, 15 and <25 kg, and 25 to <35 kg). Treatment was administered twice daily over 3 days. Plasma concentrations of artemether and its active metabolite, dihydroartemisinin (DHA), were determined at 1 and 2 h after the first dose of dispersible (n = 91) and crushed (n = 93) tablets. A full pharmacokinetic profile of lumefantrine was reconstituted on the basis of 310 (dispersible tablet) and 315 (crushed tablet) plasma samples, collected at 6 different time points (1 sample per patient). Dispersible and crushed tablets showed similar artemether and DHA maximum concentrations in plasma (C(max)) for the different body weight groups, with overall means of 175 ± 168 and 190 ± 168 ng/ml, respectively, for artemether and 64.7 ± 58.1 and 63.7 ± 65.0 ng/ml, respectively, for DHA. For lumefantrine, the population C(max) were 6.3 μg/ml (dispersible tablet) and 7.7 μg/ml (crushed tablet), whereas the areas under the concentration-time curves from time zero to the time of the last quantifiable plasma concentration measured were 574 and 636 μg · h/ml, respectively. For both formulations, descriptive quintile analyses showed no apparent association between artemether/DHA C(max) and parasite clearance time or between the lumefantrine C(max) and the occurrence of adverse events or corrected QT interval changes. The results suggest that the dispersible tablet provides adequate systemic exposure to artemether, DHA, and lumefantrine in African children with uncomplicated P. falciparum malaria.
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Development, evaluation, and application of an in silico model for antimalarial drug treatment and failure. Antimicrob Agents Chemother 2011; 55:3380-92. [PMID: 21537019 DOI: 10.1128/aac.01712-10] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
Pharmacological mechanism-based modeling was refined and used to develop an in silico model of antimalarial drug treatment validated against clinical and field data. We used this approach to investigate key features of antimalarial drug action and effectiveness, with emphasis on the current generation of artemisinin combination therapies. We made the following conclusions. (i) The development of artemisinin tolerance and resistance will, unless checked, have an immediate, large impact on the protection afforded to its partner drug and on the likely clinical efficacy of artemisinin combination therapies. (ii) Long follow-up periods are required in clinical trials to detect all drug failures; the follow-up periods of 28 days recommended by the World Health Organization are likely to miss at least 50% of drug failures, and we confirmed recent suggestions that 63 days would be a more appropriate follow-up period. (iii) Day 7 serum drug concentrations are a significant risk factor of failure, although, paradoxically, receiver operating characteristic curve analysis revealed that their predictive power is relatively poor. (iv) The pharmacokinetic properties of the partner drugs in artemisinin-containing combination therapies are the most important determinants of treatment outcome, particularly the maximum killing rate. We discuss the assumptions made in such modeling approaches and how similar approaches may be refined in future work.
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Mercer AE, Sarr Sallah M. The pharmacokinetic evaluation of artemisinin drugs for the treatment of malaria in paediatric populations. Expert Opin Drug Metab Toxicol 2011; 7:427-39. [PMID: 21320023 DOI: 10.1517/17425255.2011.557064] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023]
Abstract
INTRODUCTION The use of artemisinin combination therapies to treat uncomplicated malaria is growing and, therefore, so is the number of children exposed to these agents. As a result, there is a huge drive to develop paediatric formulations. However, relatively limited data exist regarding the pharmacokinetic properties of these drugs in this vulnerable population. AREAS COVERED The article reviews the pharmacokinetic data for artemisinin drugs used for the treatment of malaria in paediatric populations. The authors discuss how developmental and environmental factors can produce significant variation in the pharmacokinetic properties of artemisinin drugs. The authors also discuss how this variation may lead to suboptimal therapeutic drug concentrations with implications on efficacy, safety and the development of parasite resistance to these drugs. EXPERT OPINION There is currently a lack of published studies on the pharmacokinetics of artemisinin drugs in children and this subject is complicated by several interdependent variables. Therefore, the construction of a systems-based model of this subject should be a priority area in order to identify gaps in current knowledge to ensure their continued effective and safe use.
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Affiliation(s)
- Amy E Mercer
- MRC Centre for Drug Safety Science, Molecular and Clinical Pharmacology, The University of Liverpool, Sherrington Buildings, Ashton Street, L693GE Liverpool, UK.
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Li Q, Weina P. Artesunate: The Best Drug in the Treatment of Severe and Complicated Malaria. Pharmaceuticals (Basel) 2010; 3:2322-2332. [PMID: 27713355 PMCID: PMC4036668 DOI: 10.3390/ph3072322] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2010] [Revised: 07/14/2010] [Accepted: 07/20/2010] [Indexed: 11/24/2022] Open
Abstract
This review summarizes progress in treating severe and complicated malaria, which are global problems, claiming at least one million lives annually, and have been accompanied by advances in our understanding of the pathogenesis of severe malaria complications. New drugs such as intravenous artesunate (AS) and intramuscular artemether (AM) are improving outcomes and decreasing malaria deaths. Trials comparing AM to the traditional parenteral drug, quinine, have not demonstrated however convincing evidence of a mortality advantage for AM. The South East Asian Quinine Artesunate Malaria Trials (SEAQUAMAT), a multicenter, randomized, open-label study comparing AS with quinine showed that parenteral AS was shown to be associated with a 35% reduction in the risk of mortality compare to quinine, and is now the recommended treatment by the WHO for severe and complicated malaria in low-transmission areas and in the second and third trimesters of pregnancy, with almost all the benefit reported in those with high parasite counts. Artesunate is a semisynthetic derivative of artemisinin whose water solubility facilitates absorption and provides an advantage over other artemisinins because it can be formulated as oral, rectal, intramuscular, and intravenous preparations. Artesunate is rapidly hydrolyzed to dihydroartemisinin, which is the most active schizonticidal metabolite. Injectable AS results in a more rapid systemic availability of AS compared with intramuscular AM. This pharmacokinetic advantage may provide a clinical advantage in the treatments of severe and complicated malaria.
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Affiliation(s)
- Qigui Li
- Department of Drug Discovery, Division of Experimental Therapeutics, Walter Reed Army Institute of Research, 503 Robert Grant Avenue, Silver Spring, MD 20910-7500, USA.
| | - Peter Weina
- Department of Drug Discovery, Division of Experimental Therapeutics, Walter Reed Army Institute of Research, 503 Robert Grant Avenue, Silver Spring, MD 20910-7500, USA.
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The sensitivity of artesunate against Schistosoma japonicum decreased after 10 years of use in China. Parasitol Res 2010; 107:873-8. [DOI: 10.1007/s00436-010-1944-5] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2010] [Accepted: 06/01/2010] [Indexed: 10/19/2022]
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Efferth T, Kaina B. Toxicity of the antimalarial artemisinin and its dervatives. Crit Rev Toxicol 2010; 40:405-21. [DOI: 10.3109/10408441003610571] [Citation(s) in RCA: 154] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
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Tan B, Naik H, Jang IJ, Yu KS, Kirsch LE, Shin CS, Craft JC, Fleckenstein L. Population pharmacokinetics of artesunate and dihydroartemisinin following single- and multiple-dosing of oral artesunate in healthy subjects. Malar J 2009; 8:304. [PMID: 20021657 PMCID: PMC2806381 DOI: 10.1186/1475-2875-8-304] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2009] [Accepted: 12/18/2009] [Indexed: 11/24/2022] Open
Abstract
Background The population pharmacokinetics of artesunate (AS) and its active metabolite dihydroartemisinin (DHA) were studied in healthy subjects receiving single- or multiple-dosing of AS orally either in combination with pyronaridine (PYR) or as a monotherapy with or without food. Methods Data from 118 concentration-time profiles arising from 91 healthy Korean subjects were pooled from four Phase I clinical studies. Subjects received 2-5 mg/kg of single- and multiple-dosing of oral AS either in combination with PYR or as a monotherapy with or without food. Plasma AS and DHA were measured simultaneously using a validated liquid chromatography- mass spectrometric method with a lower limit of quantification of 1 ng/mL for both AS and DHA. Nonlinear mixed-effect modelling was used to obtain the pharmacokinetic and variability (inter-individual and residual variability) parameter estimates. Results A novel parent-metabolite pharmacokinetic model consisting of a dosing compartment, a central compartment for AS, a central compartment and a peripheral compartment for DHA was developed. AS and DHA data were modelled simultaneously assuming stoichiometric conversion to DHA. AS was rapidly absorbed with a population estimate of absorption rate constant (Ka) of 3.85 h-1. The population estimates of apparent clearance (CL/F) and volume of distribution (V2/F) for AS were 1190 L/h with 36.2% inter-individual variability (IIV) and 1210 L with 57.4% IIV, respectively. For DHA, the population estimates of apparent clearance (CLM/F) and central volume of distribution (V3/F) were 93.7 L/h with 28% IIV and 97.1 L with 30% IIV, respectively. The population estimates of apparent inter-compartmental clearance (Q/F) and peripheral volume of distribution (V4/F) for DHA were 5.74 L/h and 18.5 L, respectively. Intake of high-fat and high-caloric meal prior to the drug administration resulted in 84% reduction in Ka. Body weight impacted CLM/F, such that a unit change in weight resulted in 1.9-unit change in CLM/F in the same direction. Conclusions A novel simultaneous parent-metabolite pharmacokinetic model with good predictive power was developed to study the population pharmacokinetics of AS and DHA in healthy subjects following single- and multiple-dosing of AS with or without the presence of food. Food intake and weight were significant covariates for Ka and CLM/F, respectively.
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Affiliation(s)
- Beesan Tan
- College of Pharmacy, University of Iowa, Iowa City, IA, USA
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Pharmacogenetics of antimalarial drugs: effect on metabolism and transport. THE LANCET. INFECTIOUS DISEASES 2009; 9:760-74. [DOI: 10.1016/s1473-3099(09)70320-2] [Citation(s) in RCA: 108] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
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Pharmacokinetics of artemether-lumefantrine and artesunate-amodiaquine in children in Kampala, Uganda. Antimicrob Agents Chemother 2009; 54:52-9. [PMID: 19841149 DOI: 10.1128/aac.00679-09] [Citation(s) in RCA: 69] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The World Health Organization recommends the use of artemisinin-based combination therapies (ACTs) for the treatment of uncomplicated malaria. The two most widely adopted ACT regimens are artemether (AR)-lumefantrine (LR) (the combination is abbreviated AL) and amodiaquine (AQ)-artesunate (AS). Pharmacokinetic (PK) data informing the optimum dosing of these drug regimens is limited, especially in children. We evaluated PK parameters in Ugandan children aged 5 to 13 years with uncomplicated malaria treated with AL (n = 20) or AQ-AS (n = 21), with intensive venous sampling occurring at 0, 2, 4, 8, 24, and 120 h following administration of the last dose of 3-day regimens of AL (twice daily) or AQ-AS (once daily). AS achieved an estimated maximum concentration in plasma (C(max)) of 51 ng/ml and an area under the concentration-time curve from time zero to infinity (AUC(0-infinity)) of 113 ng.h/ml; and its active metabolite, dihydroartemisinin (DHA), achieved a geometric mean C(max) of 473 ng/ml and an AUC(0-infinity) of 1,404 ng.h/ml. AR-DHA exhibited a C(max) of 34/119 ng/ml and an AUC(0-infinity) of 168/382 ng.h/ml, respectively. For LR, C(max) and AUC(0-infinity) were 6,757 ng/ml and 210 microg.h/ml, respectively. For AQ and its active metabolite, desethylamodiaquine (DEAQ), the C(max)s were 5.2 ng/ml and 235 ng/ml, respectively, and the AUC(0-infinity)s were 39.3 ng.h/ml and 148 microg.h/ml, respectively. Comparison of the findings of the present study to previously published data for adults suggests that the level of exposure to LR is lower in children than in adults and that the level of AQ-DEAQ exposure is similar in children and adults. For the artemisinin derivatives, differences between children and adults were variable and drug specific. The PK results generated for children must be considered to optimize the dosing strategies for these widely utilized ACT regimens.
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Hughes KR, Biagini GA, Craig AG. Continued cytoadherence of Plasmodium falciparum infected red blood cells after antimalarial treatment. Mol Biochem Parasitol 2009; 169:71-8. [PMID: 19800372 PMCID: PMC2814047 DOI: 10.1016/j.molbiopara.2009.09.007] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2008] [Revised: 09/21/2009] [Accepted: 09/23/2009] [Indexed: 11/02/2022]
Abstract
Development of severe disease in Plasmodium falciparum malaria infection is thought to be, at least in part, due to the sequestration of trophozoite-stage infected red blood cells in the microvasculature. The process of cytoadherence is mediated by binding of the parasite protein PfEMP-1 on the surface of infected red blood cells to endothelial cell receptors. Although antimalarial treatments rapidly kill parasites, significant mortality is still seen in severe malaria, particularly within 24h of hospital admission. We find that cytoadherence of infected red blood cells continues for several hours after killing of the parasite by antimalarials; after 24h treatment using a range of antimalarials binding is approximately one-third the level of untreated parasite cultures. This is consistent with the maintained presence of PfEMP-1 on the surface of drug-treated infected red blood cells. A specific advantage of artesunate over other treatments tested is seen on addition of this drug to younger ring stage parasites, which do not mature to the cytoadherent trophozoite-stage. These findings show that cytoadherence, a potential pathogenic property of P. falciparum infected red blood cells, continues long after the parasite has been killed. These data support the development of adjunctive therapies to reverse the pathophysiological consequences of cytoadherence.
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Affiliation(s)
- Katie R Hughes
- Liverpool School of Tropical Medicine, Pembroke Place, Liverpool, L3 5QA, UK.
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Stepniewska K, Taylor W, Sirima SB, Ouedraogo EB, Ouedraogo A, Gansané A, Simpson JA, Morgan CC, White NJ, Kiechel JR. Population pharmacokinetics of artesunate and amodiaquine in African children. Malar J 2009; 8:200. [PMID: 19691851 PMCID: PMC3224946 DOI: 10.1186/1475-2875-8-200] [Citation(s) in RCA: 48] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2009] [Accepted: 08/20/2009] [Indexed: 11/21/2022] Open
Abstract
BACKGROUND Pharmacokinetic (PK) data on amodiaquine (AQ) and artesunate (AS) are limited in children, an important risk group for malaria. The aim of this study was to evaluate the PK properties of a newly developed and registered fixed dose combination (FDC) of artesunate and amodiaquine. METHODS A prospective population pharmacokinetic study of AS and AQ was conducted in children aged six months to five years. Participants were randomized to receive the new artesunate and amodiaquine FDC or the same drugs given in separate tablets. Children were divided into two groups of 70 (35 in each treatment arm) to evaluate the pharmacokinetic properties of AS and AQ, respectively. Population pharmacokinetic models for dihydroartemisinin (DHA) and desethylamodiaquine (DeAq), the principal pharmacologically active metabolites of AS and AQ, respectively, and total artemisinin anti-malarial activity, defined as the sum of the molar equivalent plasma concentrations of DHA and artesunate, were constructed using the non-linear mixed effects approach. Relative bioavailability between products was compared by estimating the ratios (and 95% CI) between the areas under the plasma concentration-time curves (AUC). RESULTS The two regimens had similar PK properties in young children with acute malaria. The ratio of loose formulation to fixed co-formulation AUCs, was estimated as 1.043 (95% CI: 0.956 to 1.138) for DeAq. For DHA and total anti-malarial activity AUCs were estimated to be the same. Artesunate was rapidly absorbed, hydrolysed to DHA, and eliminated. Plasma concentrations were significantly higher following the first dose, when patients were acutely ill, than after subsequent doses when patients were usually afebrile and clinically improved. Amodiaquine was converted rapidly to DeAq, which was then eliminated with an estimated median (range) elimination half-life of 9 (7 to 12) days. Efficacy was similar in the two treatments groups, with cure rates of 0.946 (95% CI: 0.840-0.982) in the AS+AQ group and 0.892 (95% CI: 0.787 - 0.947) in the AS/AQ group. Four out of five patients with PCR confirmed recrudescences received AQ doses < 10 mg/kg. Both regimens were well tolerated. No child developed severe, post treatment neutropaenia (<1,000/muL). There was no evidence of AQ dose related hepatotoxicity, but one patient developed an asymptomatic rise in liver enzymes that was resolving by Day-28. CONCLUSION The bioavailability of the co-formulated AS-AQ FDC was similar to that of the separate tablets for desethylamodiaquine, DHA and the total anti-malarial activity. These data support the use this new AS-AQ FDC in children with acute uncomplicated falciparum malaria.
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Affiliation(s)
- Kasia Stepniewska
- Mahidol-Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, 420/6 Rajvithi Road, Bangkok 10400, Thailand
- Centre for Clinical Vaccinology and Tropical Medicine, Churchill Hospital, Oxford, UK
| | - Walter Taylor
- Mahidol-Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, 420/6 Rajvithi Road, Bangkok 10400, Thailand
- Centre for Clinical Vaccinology and Tropical Medicine, Churchill Hospital, Oxford, UK
- Service de Médecine Internationale et Humanitaire, Hopitaux Universitaires de Genève, Switzerland
| | - Sodiomon B Sirima
- Centre National de Recherche et de Formation sur le Paludisme, Ouagadougou, Burkina Faso
- Groupe de Recherche Action en Santé (GRAS), Ouagadougou, Burkina Faso
| | - Esperance B Ouedraogo
- Centre National de Recherche et de Formation sur le Paludisme, Ouagadougou, Burkina Faso
| | - Alphonse Ouedraogo
- Centre National de Recherche et de Formation sur le Paludisme, Ouagadougou, Burkina Faso
| | - Adama Gansané
- Centre National de Recherche et de Formation sur le Paludisme, Ouagadougou, Burkina Faso
| | - Julie A Simpson
- Centre for Molecular, Environmental, Genetic and Analytic Epidemiology, The University of Melbourne, Melbourne, Australia
| | | | - Nicholas J White
- Mahidol-Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, 420/6 Rajvithi Road, Bangkok 10400, Thailand
- Centre for Clinical Vaccinology and Tropical Medicine, Churchill Hospital, Oxford, UK
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Simpson JA, Jamsen KM, Price RN, White NJ, Lindegardh N, Tarning J, Duffull SB. Towards optimal design of anti-malarial pharmacokinetic studies. Malar J 2009; 8:189. [PMID: 19656413 PMCID: PMC2732628 DOI: 10.1186/1475-2875-8-189] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2009] [Accepted: 08/06/2009] [Indexed: 12/02/2022] Open
Abstract
Background Characterization of anti-malarial drug concentration profiles is necessary to optimize dosing, and thereby optimize cure rates and reduce both toxicity and the emergence of resistance. Population pharmacokinetic studies determine the drug concentration time profiles in the target patient populations, including children who have limited sampling options. Currently, population pharmacokinetic studies of anti-malarial drugs are designed based on logistical, financial and ethical constraints, and prior knowledge of the drug concentration time profile. Although these factors are important, the proposed design may be unable to determine the desired pharmacokinetic profile because there was no formal consideration of the complex statistical models used to analyse the drug concentration data. Methods Optimal design methods incorporate prior knowledge of the pharmacokinetic profile of the drug, the statistical methods used to analyse data from population pharmacokinetic studies, and also the practical constraints of sampling the patient population. The methods determine the statistical efficiency of the design by evaluating the information of the candidate study design prior to the pharmacokinetic study being conducted. Results In a hypothetical population pharmacokinetic study of intravenous artesunate, where the number of patients and blood samples to be assayed was constrained to be 50 and 200 respectively, an evaluation of varying elementary designs using optimal design methods found that the designs with more patients and less samples per patient improved the precision of the pharmacokinetic parameters and inter-patient variability, and the overall statistical efficiency by at least 50%. Conclusion Optimal design methods ensure that the proposed study designs for population pharmacokinetic studies are robust and efficient. It is unethical to continue conducting population pharmacokinetic studies when the sampling schedule may be insufficient to estimate precisely the pharmacokinetic profile.
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Affiliation(s)
- Julie A Simpson
- Centre for Molecular, Environmental, Genetic and Analytic Epidemiology, School of Population Health, University of Melbourne, Melbourne, Victoria, Australia.
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Grobusch MP. Early rectal artesunate administration: a life-saver in remote areas? Future Microbiol 2009; 4:397-400. [DOI: 10.2217/fmb.09.16] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Evaluation of: Gomes MF, Faiz MA, Gyapong GO et al.: Pre-referral rectal artesunate to prevent death and disability in severe malaria: a placebo-controlled trial. Lancet 373, 557–566 (2009). Malaria remains a major cause of morbidity and mortality in endemic areas, particularly in children under 5 years of age in sub-Saharan Africa. Distance to healthcare facilities is a key determinant of outcome. Gomes and colleagues report that pre-referral rectal artesunate administration significantly reduced permanent disability or death in patients still not receiving inpatient treatment after more than 6 h. In contrast, no significant effect was noted if treatment was administered within less than 6 h. With some questions remaining, this strategy appears to be an important, probably highly cost-effective additional tool urgently needed to help reducing the burden of disease.
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Affiliation(s)
- Martin P Grobusch
- Infectious Diseases Unit, Division of Clinical Microbiology & Infectious Diseases, National Health Laboratory Service & School of Pathology, Faculty of Health Sciences, University of the Witwatersrand, 7 York Road, Parktown 2193, Johannesburg, South Africa and, Medical Research Unit, Albert Schweitzer Hospital, B.P. 118, Lambaréné, Gabon
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Gomes MF, Faiz MA, Gyapong JO, Warsame M, Agbenyega T, Babiker A, Baiden F, Yunus EB, Binka F, Clerk C, Folb P, Hassan R, Hossain MA, Kimbute O, Kitua A, Krishna S, Makasi C, Mensah N, Mrango Z, Olliaro P, Peto R, Peto TJ, Rahman MR, Ribeiro I, Samad R, White NJ. Pre-referral rectal artesunate to prevent death and disability in severe malaria: a placebo-controlled trial. Lancet 2009; 373:557-66. [PMID: 19059639 PMCID: PMC2646124 DOI: 10.1016/s0140-6736(08)61734-1] [Citation(s) in RCA: 150] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
BACKGROUND Most malaria deaths occur in rural areas. Rapid progression from illness to death can be interrupted by prompt, effective medication. Antimalarial treatment cannot rescue terminally ill patients but could be effective if given earlier. If patients who cannot be treated orally are several hours from facilities for injections, rectal artesunate can be given before referral and acts rapidly on parasites. We investigated whether this intervention reduced mortality and permanent disability. METHODS In Bangladesh, Ghana, and Tanzania, patients with suspected severe malaria who could not be treated orally were allocated randomly to a single artesunate (n=8954) or placebo (n=8872) suppository by taking the next numbered box, then referred to clinics at which injections could be given. Those with antimalarial injections or negative blood smears before randomisation were excluded, leaving 12 068 patients (6072 artesunate, 5996 placebo) for analysis. Primary endpoints were mortality, assessed 7-30 days later, and permanent disability, reassessed periodically. All investigators were masked to group assignment. Analysis was by intention to treat. This study is registered in all three countries, numbers ISRCTN83979018, 46343627, and 76987662. RESULTS Mortality was 154 of 6072 artesunate versus 177 of 5996 placebo (2.5%vs 3.0%, p=0.1). Two versus 13 (0.03%vs 0.22%, p=0.0020) were permanently disabled; total dead or disabled: 156 versus 190 (2.6%vs 3.2%, p=0.0484). There was no reduction in early mortality (56 vs 51 deaths within 6 h; median 2 h). In patients reaching clinic within 6 h (median 3 h), pre-referral artesunate had no significant effect on death after 6 h or permanent disability (71/4450 [1.6%] vs 82/4426 [1.9%], risk ratio 0.86 [95% CI 0.63-1.18], p=0.35). In patients still not in clinic after more than 6 h, however, half were still not there after more than 15 h, and pre-referral rectal artesunate significantly reduced death or permanent disability (29/1566 [1.9%] vs 57/1519 [3.8%], risk ratio 0.49 [95% CI 0.32-0.77], p=0.0013). INTERPRETATION If patients with severe malaria cannot be treated orally and access to injections will take several hours, a single inexpensive artesunate suppository at the time of referral substantially reduces the risk of death or permanent disability. FUNDING UNICEF/UNDP/World Bank Special Programme for Research and Training in Tropical Diseases (WHO/TDR); WHO Global Malaria Programme (WHO/GMP); Sall Family Foundation; the European Union (QLRT-2000-01430); the UK Medical Research Council; USAID; Irish Aid; the Karolinska Institute; and the University of Oxford Clinical Trial Service Unit (CTSU).
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Affiliation(s)
- M F Gomes
- UNICEF/UNDP/World Bank/WHO Special Programme for Research and Training in Tropical Diseases, Geneva, Switzerland.
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Hong X, Liu CH, Huang XT, Huang TL, Ye SM, Ou WP, Wang NS, Mi SQ. Pharmacokinetics of dihydroartemisinin in Artekin tablets for single and repeated dosing in Chinese healthy volunteers. Biopharm Drug Dispos 2008; 29:237-44. [PMID: 18350560 DOI: 10.1002/bdd.607] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
Aim. To study the pharmacokinetics of dihydroartemisinin (DHA) in Artekin (compound dihydroartemisinin) tablets in Chinese healthy volunteers. Methods. Eighteen healthy volunteers (9 males, 9 females) received Artekin tablets for oral administration. The plasma samples of DHA were analysed by liquid-liquid extraction and determined by HPLC/ESI/MS. Results. The plasma DHA concentration-time curves of single dose and repeated doses of DHA were fitted to a two-compartment open model. The mean pharmacokinetic parameters of DHA in a single dose were: t(1/2(beta))=1.245 +/- 0.495 h, C(max)=243.6 +/- 56.15 microg/l, AUC(0 --> infinity)=450 +/- 69 h x microg/l, V(d)=5.75 +/- 2.2 l/kg and Cl=3.245 +/- 0.38 l/h/kg, while in repeated doses they were: t(1/2(beta))=1.085 +/- 0.298 h, AUC(0 --> infinity)=444.35 +/- 80.43 h x ng/ml, V(d)=4.62 +/- 1.128 ml/kg, Cl=3.0125 +/- 0.875 ml/h/kg, respectively. Conclusion. The study showed that DHA in Artekin was rapidly absorbed, distributed and eliminated in the healthy subjects. The pharmacokinetic properties of DHA in Artekin were not affected by gender in a single dose. While in repeated doses accumulation of DHA did not appear after repeated doses.
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Affiliation(s)
- Xin Hong
- Institute of Clinical Pharmacology, Guangzhou University of Chinese Medicine, Guangzhou, Guangdong Province, PR China
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Sinou V, Taudon N, Mosnier J, Aglioni C, Bressolle FMM, Parzy D. Pharmacokinetics of artesunate in the domestic pig. J Antimicrob Chemother 2008; 62:566-74. [PMID: 18559353 DOI: 10.1093/jac/dkn231] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023] Open
Abstract
OBJECTIVES The aim was to study the pharmacokinetic profile of artesunate and its metabolite dihydroartemisinin (DHA) in a pig model. METHODS Thirteen pigs received either intravenous (iv) or intramuscular (im) artesunate (60 mg), with the alternative preparation given 24 h later in an open crossover design. Five of them also received an additional intra-arterial (ia) artesunate dose (60 mg). The plasma concentrations of artesunate and DHA were determined by high-performance liquid chromatography with electrochemical detection. Population modelling was performed with NONMEM, using a two-compartment model. RESULTS Plasma concentration-time profiles were comparable to those observed in humans, with a rapid and biphasic decline for both artesunate and DHA. Following an iv bolus, artesunate had a median maximum plasma concentration (C(max)) of 13.8 microM [interquartile range (IQR), 10.4-22.1 microM], elimination half-life (t(1/2)) = 18 min (IQR, 16-22 min), total plasma clearance (CL) = 5.58 L/h/kg (IQR, 3.31-5.91 L/h/kg) and volume of distribution (V(d)) = 1.85 L/kg (IQR, 1.27-3.20 L/kg). The median C(max) value for DHA was 3.30 microM (IQR, 2.08-5.95 microM), t(1/2) = 26 min (IQR, 23-31 min), CL/Fm = 4.37 L/h/kg (IQR, 3.29-6.87 L/h/kg) and V(d)/Fm = 2.56 L/kg (IQR, 1.93-4.49 L/kg). Artesunate and DHA pharmacokinetic parameters were similar after ia administration. Following im dosing, median artesunate C(max) was 4.81 microM (IQR, 3.74-5.40 microM), t(1/2) = 18 min (IQR, 16-28 min), CL = 4.37 L/h/kg (IQR, 4.13-4.68 L/h/kg) and V(d) = 2.07 L/kg (IQR, 1.83-2.79 L/kg); the bioavailability was 100%. For DHA, median C(max) was 1.43 microM (IQR, 1.00-1.92 microM), t(1/2) = 27 min (IQR, 25-37 min), CL/Fm = 4.68 L/h/kg (IQR, 3.35-6.73 L/h/kg) and V(d)/Fm = 3.31 L/kg (IQR, 2.89-4.27 L/kg). CONCLUSIONS The pharmacokinetic properties of artesunate and DHA in pigs were similar to those reported in humans, suggesting that the swine model is suitable for determining the preclinical pharmacokinetics of artemisinin derivatives.
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Affiliation(s)
- Véronique Sinou
- Physiopathology and Parasitical Pharmacology Research Unit, Institut de Médecine Tropicale du Service de Santé des Armées and UMR-MD3, Université de la Méditerranée, Marseille, France.
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Gomes M, Ribeiro I, Warsame M, Karunajeewa H, Petzold M. Rectal artemisinins for malaria: a review of efficacy and safety from individual patient data in clinical studies. BMC Infect Dis 2008; 8:39. [PMID: 18373841 PMCID: PMC2364627 DOI: 10.1186/1471-2334-8-39] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2007] [Accepted: 03/28/2008] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Rectal administration of artemisinin derivatives has potential for early treatment for severe malaria in remote settings where injectable antimalarial therapy may not be feasible. Preparations available include artesunate, artemisinin, artemether and dihydroartemisinin. However each may have different pharmacokinetic properties and more information is needed to determine optimal dose and comparative efficacy with each another and with conventional parenteral treatments for severe malaria. METHODS Individual patient data from 1167 patients in 15 clinical trials of rectal artemisinin derivative therapy (artesunate, artemisinin and artemether) were pooled in order to compare the rapidity of clearance of Plasmodium falciparum parasitaemia and the incidence of reported adverse events with each treatment. Data from patients who received comparator treatment (parenteral artemisinin derivative or quinine) were also included. Primary endpoints included percentage reductions in parasitaemia at 12 and 24 hours. A parasite reduction of >90% at 24 hours was defined as parasitological success. RESULTS Artemisinin and artesunate treatment cleared parasites more rapidly than parenteral quinine during the first 24 hours of treatment. A single higher dose of rectal artesunate treatment was five times more likely to achieve >90% parasite reductions at 24 hours than were multiple lower doses of rectal artesunate, or a single lower dose administration of rectal artemether. CONCLUSION Artemisinin and artesunate suppositories rapidly eliminate parasites and appear to be safe. There are less data on artemether and dihydroartemisinin suppositories. The more rapid parasite clearance of single high-dose regimens suggests that achieving immediate high drug concentrations may be the optimal strategy.
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Affiliation(s)
- Melba Gomes
- UNICEF/UNDP/World Bank/WHO Special Programme for Research and Training in Tropical Diseases, World Health Organization, 20 Avenue Appia, Geneva 27, Switzerland.
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Barnes KI, Watkins WM, White NJ. Antimalarial dosing regimens and drug resistance. Trends Parasitol 2008; 24:127-34. [DOI: 10.1016/j.pt.2007.11.008] [Citation(s) in RCA: 103] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2007] [Revised: 10/18/2007] [Accepted: 11/22/2007] [Indexed: 01/29/2023]
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Affiliation(s)
- Nicholas Day
- Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand, and the Centre for Tropical Medicine, Nuffield Department of Clinical Medicine, John Radcliffe Hospital, University of Oxford, Oxford, United Kingdom
| | - Arjen M. Dondorp
- Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand, and the Centre for Tropical Medicine, Nuffield Department of Clinical Medicine, John Radcliffe Hospital, University of Oxford, Oxford, United Kingdom
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Haynes RK, Chan HW, Lung CM, Ng NC, Wong HN, Shek LY, Williams ID, Cartwright A, Gomes MF. Artesunate and Dihydroartemisinin (DHA): Unusual Decomposition Products Formed under Mild Conditions and Comments on the Fitness of DHA as an Antimalarial Drug. ChemMedChem 2007; 2:1448-63. [PMID: 17694524 DOI: 10.1002/cmdc.200700064] [Citation(s) in RCA: 71] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
Artesunate drug substance, for which a rectal capsule formulation is under development for the treatment of severe malaria, when heated at 100 degrees C for 39 h gives beta-artesunate, artesunate dimers, 9,10-anhydrodihydroartemisinin (glycal), a DHA beta-formate ester, and smaller amounts of other products that arise via intermediate formation of dihydroartemisinin (DHA) and subsequent thermal degradation. Solid DHA at 100 degrees C provides an epimeric mixture of a known peroxyhemiacetal, arising via ring opening to a hydroperoxide and re-closure, smaller amounts of a 3:1 mixture of epimers of a known tricarbonyl compound, and a single epimer of a new dicarbonyl compound. The latter arises via homolysis of the peroxide and an ensuing cascade of alpha-cleavage reactions which leads to loss of formic acid incorporating the C10 carbonyl group of DHA exposed by this 'unzipping' cascade. The tricarbonyl compound that arises via peroxide homolysis and extrusion of formic acid from a penultimate hydroxyformate ester incorporating C12 of the original DHA, is epimeric at the exocyclic 1''-aldehyde, and not in the cyclohexanone moiety. It is converted into the dicarbonyl compound by peroxide-induced deformylation. The dicarbonyl compound is not formed during anhydrous ferrous bromide mediated decomposition of DHA at room temperature, which provides the 1''-R epimer of the tricarbonyl compound as the dominant product; this equilibrates at room temperature to the 3:1 mixture of epimers of the tricarbonyl compound obtained from thermolysis. Each of artesunate and DHA decomposes readily under aqueous acidic conditions to provide significant amounts of the peroxyhemiacetal, which, like DHA, decomposes to the inert end product 2-deoxyartemisinin under acidic or basic conditions. DHA and the peroxyhemiacetal are the principal degradants in aged rectal capsule formulations of artesunate. TGA analysis and thermal degradation of DHA reveals a thermal lability which would pose a problem not only in relation to ICH stability testing guidelines, but in the use of DHA in fixed formulations currently under development. This thermolability coupled with the poor physicochemical properties and relative oral bioavailability of DHA suggests that it is inferior to artesunate in application as an antimalarial drug.
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Affiliation(s)
- Richard K Haynes
- Department of Chemistry, Open Laboratory of Chemical Biology, Institute of Molecular Technology for Drug Discovery and Synthesis, Institute of The Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong, PR China.
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