Observational studyThe Lancet. Microbe2026
Parasite clearance in patients with Plasmodium vivax monoinfection treated with artesunate in Cambodia: an observational secondary analysis of trial data.
Observational study in The Lancet. Microbe, 2026. The graph could read no effect estimate from its abstract, so it casts no vote on the map. Cited by 2 papers.
What it found
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The abstract states no effect estimate the extractor could read, or names no intervention and outcome on the map, so this paper lights no cell and moves no belief. It is still indexed, cited and linked below.
The trial behind it
Trials whose registry record cites this paper, or whose number appears in the abstract. A trial that started after this paper was published is citing it as background, not reporting it.
Neither the registry nor the abstract names a trial number. If this is a trial report, that itself is worth knowing.
Who cites it
2 citing papers in PubMed.
- MaRNAV-1, an intracellular virus ofbioRxiv : the preprint server for biology · 2026Article
- Frequent and genetically diverseResearch square · 2026Article
Corrections and comments
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Authors and funding
16 authors.
Funding
Abstract
backgroundArtemisinin-based combination therapies are the frontline drugs for the treatment of malaria infections, but, for Plasmodium falciparum, the efficacy of artemisinin is threatened by the spread of resistance. Plasmodium vivax is the second most common cause of human malaria, but there is little information on its susceptibility to artemisinin due to the lack of an in-vitro culture system. This study aims to characterise the response of P vivax to artesunate using clinical, genomic, and transcriptomic data from infected individuals in Cambodia.
methodsWe analysed 161 P vivax infections from 87 patients (six female and 81 male; median age 20 years [IQR 17-26]) enrolled between Nov 10, 2021, and Nov 18, 2022, in a drug efficacy study in Cambodia and treated with 2 mg/kg/day of artesunate for 7 days. To determine clearance rates, we measured parasitaemia before, and 1 h, 2 h, 4 h, 8 h, and 16 h after the first dose of artesunate, and then at 24-h intervals during the 7 days of artesunate therapy. We also examined the parasites' genome sequences and used RNA sequencing of 31 infections to analyse changes in parasite gene expression upon treatment.
findingsAll infections were successfully cleared by day 3. However, 49 of the infections displayed a slow clearance after treatment, including nine (6%) infections with a parasite clearance slope half-life greater than 5 h. We observed no significant association between slow clearance and either patient or infection characteristics (including the infection's stage composition). Analyses of gene expression showed that, while fast-clearing parasites displayed significant changes in gene expression immediately upon treatment, slow-clearing parasites had a delayed gene expression response characterised notably by a downregulation of genes associated with haemoglobin endocytosis and digestion.
interpretationSome Cambodian P vivax parasites clear slowly after artesunate treatment, possibly due to a downregulation of haemoglobin metabolism that might reduce the efficiency of the artesunate. The slow clearance could allow parasites to outlast artesunate treatment and facilitate emergence of resistance to the artemisinin-combination therapy partner drug, threatening malaria elimination effort.
fundingUS National Institutes of Health.
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