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Study groups

WWARN facilitates a number of collaborative Study Groups to undertake individual patient data meta-analyses to answer specific research questions about malaria drug resistance. Gathering data sets from multiple studies increases sample sizes, so that trends or sub-population effects can be identified with greater certainty. Working together and combining data from different regions and populations is improving our understanding of drug resistance and strengthening global efforts to control and eventually eliminate malaria.

Piperaquine Pharmacokinetics in Pregnancy Study Group

Determining the effects of pregnancy on piperaquine pharmacokinetics. The analysis aims to contribute evidence needed to inform recommendations on the use and optimal dosing of piperaquine in pregnant women.
Determining the effects of pregnancy on piperaquine pharmacokinetics. The analysis aims to contribute evidence needed to inform recommendations on the use and optimal dosing of piperaquine in pregnant women.
 

Correlation between K13 mutations and clinical phenotype Study Group

A pooled analysis on the relationship between K13 molecular marker and parasite clearance data. The Study Group closed to new participants in December 2015 . The Study Group closed to new participants in December 2015. Data analysis and manuscript drafting have been completed and awaiting approval by Study Group members. Publication is planned for the end of 2018.

Vivax After Falciparum Study Group

The aim of this study group is to explore the link between P. vivax recurrence and prior P. falciparum treatment, including increased risk of vivax parasitaemia due to acute malaria infection.

Antimalarial–Antiretroviral Study Groups

Individual patient data (IPD) meta-analyses to determine the effect of antiretroviral (ARV) drug-drug interactions and HIV disease on antimalarial drug pharmacokinetics (PK) and/or pharmacodynamics (PD).

ACT-ARV Safety Study Group

This is an extension of a planned dihydroartemisinin-piperaquine (DP) Safety Study Group, which aims to consider the effect of HIV disease and co-administration of widely-used antiretroviral (ARVs) on the safety of DP. Due to a lack of available DP studies, the individual patient data (IPD) meta-analysis will have greater public health value when these results were compared to other ACTs.

Artemether-Lumefantrine / ARV PK Study Group

A meta-analysis of individual patient data (IPD) to determine the effect of antiretroviral (ARV) drug-drug interactions and HIV disease on artemether and lumefantrine pharmacokinetics (PK). The analysis aims to contribute evidence needed to inform recommendations on the use and optimal dosing of artemether-lumefantrine (AL) in HIV-infected patients.

Molecular Markers of Resistance in West Africa Study Group

This Study Group aims to bring together and explore the latest evidence on the prevalence of molecular markers associated with antimalarial drug resistance in West African Countries.

Ivermectin Exposure in Small Children Study Group

The Ivermectin Exposure in Small Children Study Group aims to assess safety profile of ivermectin exposure in children less than 15 kilograms

Subpatent Malaria and Pregnancy Outcome Study Group

The Subpatent Malaria and Pregnancy Outcome Study Group aims to explore the relationship between subpatent Plasmodium falciparum malaria infection and pregnancy outcome

Malaria in Pregnancy Treatment Efficacy Study Group

Assessing the efficacy of a range of antimalarials used for the treatment of P. falciparum malaria in all trimesters of pregnancy in Africa and Asia
The MiP Treatment Efficacy Study Group was formed in July 2016, with a call to interested researchers with relevant data sets.

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Antimalarial – Lumefantrine POP/PK Study Group

Determining the optimal Artemether-lumefantrine antimalarial dosing for young children and pregnant women: A pharmacokinetic-pharmacodynamic meta-analysis.

ACT Malaria and Malnutrition Study Group

A pooled analysis that assessed the effect of various nutritional indicators in treatment outcome in children aged 6-59 months treated with artemisinin based combination therapies for uncomplicated P. falciparum malaria.
This group has published: Complex interactions between malaria and malnutrition: a systematic literature review. Das D et al. BMC Medicine. 2018 Oct 29;16(1):186. A news articles summarises the results.

Amodiaquine PK/PD Study Group

Analysing PK/PD data to identify inadequate drug exposure and inform antimalarial dosage
A pooled pharmacokinetic/pharmacodynamics (PK/PD) analysis of amodiaquine (AQ) is complete. The analysis focused on a population pharmacokinetic/pharmacodynamic model of amodiaquine and its active metabolite desethyl-amodiaquine in patients who received either amodiaquine as a monotherapy regimen or in combination with artesunate. The full covariate analysis explored the effects of fixed versus loose dose formulations, age, nutrition status, baseline parasitemia and sample matrix.
Publication: WWARN Amodiaquine PK Study Group. Population Pharmacokinetics of the Antimalarial Amodiaquine: a Pooled Analysis to Optimise Dosing. Denti et al. Antimicrobial Agents and Chemotherapy. 2018, Sept 24:62(10)

Vivax Recurrence Study Group

Analysis of risk factors of Plasmodium vivax early and late recurrence. 
Published in July 2018.

Piperaquine PK/PD Study Group

Analysing PK/PD data to identify inadequate drug exposure and inform dosage
A pooled piperaquine pharmacokinetic analysed the exposure to piperaquine in different populations in order to identify patient groups at particular risk of treatment failure, such as young children and pregnant women. The model can be used to optimise the dose in these vulnerable populations in order to give all patients an equal chance of cure.
The pharmacokinetic analysis has been finalised and published.

Gametocyte Carriage Study Group

A pooled analysis of Plasmodium falciparum gametocyte carriage
The purpose of this Study Group is to assess the risk factors for treatment failure associated with gametocyte carriage and clearance across a range of endemic settings and antimalarial drug treatments. To achieve this requires a standardised database and a set of metrics which are derived in a systemic manner. Data within the WWARN Data Centre provide an excellent opportunity. 
Study published on 24 July 2016:
WWARN Gametocyte Study Group. Gametocyte carriage in uncomplicatedPlasmodium falciparum malaria following treatment with artemisinin combination therapy: a systematic review and meta-analysis of individual patient data. BMC Medicine 2016 14:79 DOI: 10.1186/s12916-016-0621-7

Lumefantrine PK/PD Study Group

Analysing PK/PD data to identify inadequate drug exposure and inform dosage
A pooled lumefantrine pharmacokinetic-pharmacodynamic (PK/PD) analysis is being conducted to evaluate the exposure to lumefantrine in different populations to identify patient groups (such as young children and pregnant women) at particular risk of treatment failure. Further, to identify the pharmacokinetic-pharmacodynamic relationship of lumefantrine in the treatment of uncomplicated falciparum malaria. The group will use the the population PK-PD analysis and model developed to conduct in-silico dose optimisations.
Publication details:
WWARN Lumefantrine PK/PD Study Group. 'Artemether-lumefantrine treatment of uncomplicated Plasmodium falciparum malaria: a systematic review and meta-analysis of day 7 lumefantrine concentrations and therapeutic response using individual patient data'. Published in BMC Medicine 2015. 13:227  doi:10.1186/s12916-015-0456-7.
Follow-on analysis:
Artemether-lumefantrine dosing for malaria treatment in young children and pregnant women: A pharmacokinetic-pharmacodynamic meta-analysis. Published in PLOS Medicine June 2018. 15 (6): 1-27. Doi: 10.1371/journal.pmed.1002579  PMID: 29894518

ACT Africa Baseline Study Group

Baseline information on parasitological response to ACTs in Africa
A pooled analysis to assess the baseline early parasitological response after artemisinin combination therapy (ACT) treatments in sub-Saharan Africa. The analysis compiles the day 3 parasite positivity rates (PPR) in patients with uncomplicated Plasmodium falciparum malaria enrolled in ACT clinical efficacy trials.
The Study Group closed in March 2013. A draft manuscript has been finalised and shared with the Study Group members in February 2015. The study was published in BMC Medicine in September 2015.
Publication details: 
WWARN Artemisinin based Combination Therapy (ACT) Africa Baseline Study Group, Clinical determinants of early parasitological response to ACTs in African patients with uncomplicated falciparum malaria: a literature review and meta-analysis of individual patient data. BMC Medicine 2015, 13:212 doi:10.1186/s12916-015-0445-x

DP Dose Impact Study Group

Effect of DP mg/kg dosing strategies on the risk of treatment failure
A pooled analysis to assess the impact of weight adjusted (mg/kg) dose variations of dihydroartemisinin-piperaquine (DP) on the therapeutic efficacy of both drugs combined. The Study Group assessed if the dose of piperaquine administered to patients was a risk factor for recrudescence, (recurrence of symptoms).
The Study Group closed in March 2013. A paper was published in Plos Medicine in December 2013. Results from this study group provided evidence for the revised recommendations for optimal use of artemisinin combination therapies included in the updated WHO ‘Guidelines for the Treatment of Malaria in June 2015.
Related publications:
The WorldWide Antimalarial Resistance Network (WWARN) DP Study Group (2013) The Effect of Dosing Regimens on the Antimalarial Efficacy of Dihydroartemisinin-Piperaquine: A Pooled Analysis of Individual Patient Data. PLOS Med 10(12): e1001564. doi:10.1371/journal.pmed.1001564

AL Dose Impact Study Group

Effect of AL mg/kg dosing strategies on the risk of treatment failure
A pooled analysis to assess the impact of weight adjusted (mg/kg) dose variations of artemether-lumefantrine (AL) on the therapeutic efficacy of both drugs combined. The Study Group assessed if the dose of lumefantrine administered to the patients was a risk factor for recrudescence (recurrence of symptoms).
The study group closed in March 2013. A manuscript was submitted to Lancet Infectious Diseases in June 2014 and accepted for publication in February 2015.  The manuscript for Artemether-Lumefantrine (AL) Dose Impact Study Group was published by the Lancet Infectious Diseases in March 2015.
Publication details:
Worldwide Antimalarial Resistance Network (WWARN) AL Does Impact Study Group. The effect of dose on the antimalarial efficacy of artemether-lumefantrine: a systematic review and pooled analysis of individual patient data. The Lancet Infectious Diseases 2015; D-14-00566R1; DOI 10.1016 S1473-3099 (15)70024-1

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