Determinants of dihydro- #artemisinin-piperaquine #treatment #failure in #Plasmodium falciparum #malaria in #Cambodia, #Thailand, and #Vietnam: a prospective clinical, pharmacological, and genetic study (Lancet Infect Dis., abstract)

[Source: The Lancet Infectious Diseases, full page: (LINK). Abstract, edited.]

Determinants of dihydroartemisinin-piperaquine treatment failure in Plasmodium falciparum malaria in Cambodia, Thailand, and Vietnam: a prospective clinical, pharmacological, and genetic study

Rob W van der Pluijm, MD, Prof Mallika Imwong, PhD, Nguyen Hoang Chau, MD, Nhu Thi Hoa, MD, Nguyen Thanh Thuy-Nhien, PhD, Ngo Viet Thanh, MD, et al.

Open Access / Published: July 22, 2019 / DOI: https://doi.org/10.1016/S1473-3099(19)30391-3

 

Summary

Background

The emergence and spread of resistance in Plasmodium falciparum malaria to artemisinin combination therapies in the Greater Mekong subregion poses a major threat to malaria control and elimination. The current study is part of a multi-country, open-label, randomised clinical trial (TRACII, 2015–18) evaluating the efficacy, safety, and tolerability of triple artemisinin combination therapies. A very high rate of treatment failure after treatment with dihydroartemisinin-piperaquine was observed in Thailand, Cambodia, and Vietnam. The immediate public health importance of our findings prompted us to report the efficacy data on dihydroartemisinin-piperaquine and its determinants ahead of the results of the overall trial, which will be published later this year.

Methods

Patients aged between 2 and 65 years presenting with uncomplicated P falciparum or mixed species malaria at seven sites in Thailand, Cambodia, and Vietnam were randomly assigned to receive dihydroartemisinin-piperaquine with or without mefloquine, as part of the TRACII trial. The primary outcome was the PCR-corrected efficacy at day 42. Next-generation sequencing was used to assess the prevalence of molecular markers associated with artemisinin resistance (kelch13 mutations, in particular Cys580Tyr) and piperaquine resistance (plasmepsin-2 and plasmepsin-3amplifications and crt mutations). This study is registered with ClinicalTrials.gov, number NCT02453308.

Findings

Between Sept 28, 2015, and Jan 18, 2018, 539 patients with acute P falciparum malaria were screened for eligibility, 292 were enrolled, and 140 received dihydroartemisinin-piperaquine. The overall Kaplan-Meier estimate of PCR-corrected efficacy of dihydroartemisinin-piperaquine at day 42 was 50·0% (95% CI 41·1–58·3). PCR-corrected efficacies for individual sites were 12·7% (2·2–33·0) in northeastern Thailand, 38·2% (15·9–60·5) in western Cambodia, 73·4% (57·0–84·3) in Ratanakiri (northeastern Cambodia), and 47·1% (33·5–59·6) in Binh Phuoc (southwestern Vietnam). Treatment failure was associated independently with plasmepsin2/3amplification status and four mutations in the crt gene (Thr93Ser, His97Tyr, Phe145Ile, and Ile218Phe). Compared with the results of our previous TRACI trial in 2011–13, the prevalence of molecular markers of artemisinin resistance (kelch13 Cys580Tyr mutations) and piperaquine resistance (plasmepsin2/3 amplifications and crtmutations) has increased substantially in the Greater Mekong subregion in the past decade.

Interpretation

Dihydroartemisinin-piperaquine is not treating malaria effectively across the eastern Greater Mekong subregion. A highly drug-resistant P falciparum co-lineage is evolving, acquiring new resistance mechanisms, and spreading. Accelerated elimination of P falciparum malaria in this region is needed urgently, to prevent further spread and avoid a potential global health emergency.

Funding

UK Department for International Development, Wellcome Trust, Bill & Melinda Gates Foundation, Medical Research Council, and National Institutes of Health.

Keywords: Malaria; Plasmodium falciparum; Artemisin; Drugs resistance; Thailand; Cambodia; Laos; Vietnam.

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Efficacy and safety of #primaquine and methylene blue for #prevention of #Plasmodium falciparum #transmission in #Mali: a phase 2, single-blind, randomised controlled trial (Lancet Infect Dis., abstract)

[Source: The Lancet Infectious Diseases, full page: (LINK). Abstract, edited.]

Efficacy and safety of primaquine and methylene blue for prevention of Plasmodium falciparum transmission in Mali: a phase 2, single-blind, randomised controlled trial

Prof Alassane Dicko, MD*, Michelle E Roh, MPH*, , Halimatou Diawara, MD, Almahamoudou Mahamar, PharmD, Harouna M Soumare, PharmD, Kjerstin Lanke, BSc, John Bradley, PhD, Koualy Sanogo, MD, Daouda T Kone, MD, Kalifa Diarra, PharmD, Sekouba Keita, MS, Djibrilla Issiaka, MD, Prof Sekou F Traore, PhD, Prof Charles McCulloch, PhD, Will J R Stone, MSc, Jimee Hwang, MD, Prof Olaf Müller, PhD, Joelle M Brown, PhD, Vinay Srinivasan, BA, Prof Chris Drakeley, PhD, Prof Roly Gosling, MD†, Ingrid Chen, PhD†, Teun Bousema, PhD†

*Contributed equally

†Contributed equally

Published: 05 February 2018 / Open Access / DOI: https://doi.org/10.1016/S1473-3099(18)30044-6

© 2018 The Author(s). Published by Elsevier Ltd.

 

Summary

Background

Primaquine and methylene blue are gametocytocidal compounds that could prevent Plasmodium falciparum transmission to mosquitoes. We aimed to assess the efficacy and safety of primaquine and methylene blue in preventing human to mosquito transmission of P falciparum among glucose-6-phosphate dehydrogenase (G6PD)-normal, gametocytaemic male participants.

Methods

This was a phase 2, single-blind, randomised controlled trial done at the Clinical Research Centre of the Malaria Research and Training Centre (MRTC) of the University of Bamako (Bamako, Mali). We enrolled male participants aged 5–50 years with asymptomatic P falciparum malaria. G6PD-normal participants with gametocytes detected by blood smear were randomised 1:1:1:1 in block sizes of eight, using a sealed-envelope design, to receive either sulfadoxine-pyrimethamine and amodiaquine, sulfadoxine-pyrimethamine and amodiaquine plus a single dose of 0·25 mg/kg primaquine, dihydroartemisinin-piperaquine, or dihydroartemisinin-piperaquine plus 15 mg/kg per day methylene blue for 3 days. Laboratory staff, investigators, and insectary technicians were masked to the treatment group and gametocyte density of study participants. The study pharmacist and treating physician were not masked. Participants could request unmasking. The primary efficacy endpoint, analysed in all infected patients with at least one infectivity measure before and after treatment, was median within-person percentage change in mosquito infectivity 2 and 7 days after treatment, assessed by membrane feeding. This study is registered with ClinicalTrials.gov, number NCT02831023.

Findings

Between June 27, 2016, and Nov 1, 2016, 80 participants were enrolled and assigned to the sulfadoxine-pyrimethamine and amodiaquine (n=20), sulfadoxine-pyrimethamine and amodiaquine plus primaquine (n=20), dihydroartemisinin-piperaquine (n=20), or dihydroartemisinin-piperaquine plus methylene blue (n=20) groups. Among participants infectious at baseline (54 [68%] of 80), those in the sulfadoxine-pyrimethamine and amodiaquine plus primaquine group (n=19) had a median 100% (IQR 100 to 100) within-person reduction in mosquito infectivity on day 2, a larger reduction than was noted with sulfadoxine-pyrimethamine and amodiaquine alone (n=12; −10·2%, IQR −143·9 to 56·6; p<0·0001). The dihydroartemisinin-piperaquine plus methylene blue (n=11) group had a median 100% (IQR 100 to 100) within-person reduction in mosquito infectivity on day 2, a larger reduction than was noted with dihydroartemisinin-piperaquine alone (n=12; −6·0%, IQR −126·1 to 86·9; p<0·0001). Haemoglobin changes were similar between gametocytocidal arms and their respective controls. After exclusion of blue urine, adverse events were similar across all groups (59 [74%] of 80 participants had 162 adverse events overall, 145 [90%] of which were mild).

Interpretation

Adding a single dose of 0·25 mg/kg primaquine to sulfadoxine-pyrimethamine and amodiaquine or 3 days of 15 mg/kg per day methylene blue to dihydroartemisinin-piperaquine was highly efficacious for preventing P falciparum transmission. Both primaquine and methylene blue were well tolerated.

Funding

Bill & Melinda Gates Foundation, European Research Council.

Keywords: Malaria; Mali; Piperaquine; Methylene Blue; Primaquine.

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#Origins of the current #outbreak of #MDR #malaria in southeast #Asia: a retrospective genetic study (Lancet Infect Dis., abstract)

[Source: The Lancet Infectious Diseases, full page: (LINK). Abstract, edited.]

Origins of the current outbreak of multidrug-resistant malaria in southeast Asia: a retrospective genetic study

Roberto Amato, PhD, Richard D Pearson, PhD, Jacob Almagro-Garcia, PhD, Chanaki Amaratunga, PhD, Pharath Lim, MD, Seila Suon, MD, Sokunthea Sreng, Eleanor Drury, Sc, Jim Stalker, MA, Olivo Miotto, PhD, Rick M Fairhurst, MD, Prof Dominic P Kwiatkowski, FRCP

Published: 01 February 2018 / Open Access / DOI: https://doi.org/10.1016/S1473-3099(18)30068-9

© 2018 The Author(s). Published by Elsevier Ltd.

 

Summary

Background

Antimalarial resistance is rapidly spreading across parts of southeast Asia where dihydroartemisinin–piperaquine is used as first-line treatment for Plasmodium falciparum malaria. The first published reports about resistance to antimalarial drugs came from western Cambodia in 2013. Here, we analyse genetic changes in the P falciparum population of western Cambodia in the 6 years before those reports.

Methods

We analysed genome sequence data on 1492 P falciparum samples from 11 locations across southeast Asia, including 464 samples collected in western Cambodia between 2007 and 2013. Different epidemiological origins of resistance were identified by haplotypic analysis of the kelch13artemisinin resistance locus and the plasmepsin 2–3 piperaquine resistance locus.

Findings

We identified more than 30 independent origins of artemisinin resistance, of which the KEL1 lineage accounted for 140 (91%) of 154 parasites resistant to dihydroartemisinin–piperaquine. In 2008, KEL1 combined with PLA1, the major lineage associated with piperaquine resistance. By 2013, the KEL1/PLA1 co-lineage had reached a frequency of 63% (24/38) in western Cambodia and had spread to northern Cambodia.

Interpretation

The KEL1/PLA1 co-lineage emerged in the same year that dihydroartemisinin–piperaquine became the first-line antimalarial drug in western Cambodia and spread rapidly thereafter, displacing other artemisinin-resistant parasite lineages. These findings have important implications for management of the global health risk associated with the current outbreak of multidrug-resistant malaria in southeast Asia.

Funding

Wellcome Trust, Bill & Melinda Gates Foundation, Medical Research Council, UK Department for International Development, and the Intramural Research Program of the National Institute of Allergy and Infectious Diseases.

Keywords: Malaria; Asia Region; Antibiotics; Drugs Resistance; Artemisin; Piperaquine.

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