Publications by authors named "Pukrittayakamee S"

Background: Parenteral artesunate is the first-line therapy for severe malaria. Artesunate, in its current formulation, must be prepared immediately before administration by first dissolving in sodium bicarbonate solution and then diluting in saline. A novel solvent for rapid and stable single step reconstitution of artesunate was recently developed showing improved solubility and stability.

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Background: Hydroxychloroquine (HCQ) has proved ineffective in treating patients hospitalised with Coronavirus Disease 2019 (COVID-19), but uncertainty remains over its safety and efficacy in chemoprevention. Previous chemoprevention randomised controlled trials (RCTs) did not individually show benefit of HCQ against COVID-19 and, although meta-analysis did suggest clinical benefit, guidelines recommend against its use.

Methods And Findings: Healthy adult participants from the healthcare setting, and later from the community, were enrolled in 26 centres in 11 countries to a double-blind, placebo-controlled, randomised trial of COVID-19 chemoprevention.

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In preparation for mass vaccinations with R21/Matrix-M™ combined with mass administrations of dihydroartemisinin, piperaquine, and a single low dose primaquine we assessed the tolerability, safety, and potential interactions of this combination affecting immunogenicity or pharmacokinetics. 120 healthy Thai volunteers were randomised to receive either antimalarials combined with vaccinations (n = 50), vaccinations alone (n = 50), or antimalarials only (n = 20). Three rounds of vaccines and antimalarials were administered one month apart.

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Article Synopsis
  • Antiviral drugs are crucial in preventing severe outcomes from COVID-19, and measuring the clearance of SARS-CoV-2 in patients helps assess their effectiveness.
  • A meta-analysis of data from the PLATCOV trial focused on how viral clearance rates change over time in patients to improve the design of future antiviral drug evaluations.
  • The study found that effective antiviral interventions speed up the initial phase of viral clearance, with the best results observed within the first five days after treatment begins.
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Background: Primaquine is an 8-aminoquinoline antimalarial. It is the only widely available treatment to prevent relapses of malaria. The 8-aminoquinolines cause dose-dependent haemolysis in glucose-6-phosphate dehydrogenase deficiency (G6PDd).

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Unlabelled: In early symptomatic COVID-19 treatment, high dose oral favipiravir did not accelerate viral clearance.

Background: Favipiravir, an anti-influenza drug, has in vitro antiviral activity against SARS-CoV-2. Clinical trial evidence to date is inconclusive.

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Background: The optimal dosing of primaquine to prevent relapsing malaria in South Asia remains unclear. We investigated the efficacy and safety of different primaquine regimens to prevent relapse.

Methods: A systematic review identified efficacy studies from South Asia published between 1 January 2000 and 23 August 2021.

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Article Synopsis
  • - The ongoing PLATCOV trial compares the antiviral effects of molnupiravir and ritonavir-boosted nirmatrelvir in treating early symptomatic COVID-19 patients across various countries including Thailand and Brazil, using viral clearance as the main measure of effectiveness.
  • - In this phase 2, open-label trial, low-risk adults aged 18-50 with COVID-19 symptoms were randomly assigned to one of seven treatment groups, including both antiviral drugs and a no-drug control group, ensuring at least 20% of participants received no medication.
  • - The study assesses the rate of viral clearance and treatment safety over one week using a Bayesian model to evaluate the effectiveness of the antiviral treatments, aiming to establish if either
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Article Synopsis
  • The study investigates the safety of primaquine, a medication used to eliminate dormant liver-stage parasites of Plasmodium vivax, focusing on its impact on hemolysis risk.
  • Researchers conducted a systematic review and meta-analysis of clinical studies published from 2000 to 2023, including data on patients treated with different primaquine regimens.
  • The main outcome measured was the significant reduction in hemoglobin levels (more than 25% to below 7 g/dL) by day 14 post-treatment, with analysis based on the G6PD enzyme activity levels in patients.
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Background: Primaquine is used to eliminate Plasmodium vivax hypnozoites, but its optimal dosing regimen remains unclear. We undertook a systematic review and individual patient data meta-analysis to investigate the efficacy and tolerability of different primaquine dosing regimens to prevent P vivax recurrence.

Methods: For this systematic review and individual patient data meta-analysis, we searched MEDLINE, Web of Science, Embase, and Cochrane Central for prospective clinical studies of uncomplicated P vivax from endemic countries published between Jan 1, 2000, and June 8, 2023.

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Background: Uncertainty over the therapeutic benefit of parenteral remdesivir in coronavirus disease 2019 (COVID-19) has resulted in varying treatment guidelines.

Methods: In a multicenter open-label, controlled, adaptive, pharmacometric platform trial, low-risk adult patients with early symptomatic COVID-19 were randomized to 1 of 8 treatment arms including intravenous remdesivir (200 mg followed by 100 mg daily for 5 days) or no study drug. The primary outcome was the rate of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) clearance (estimated under a linear model fit to the daily log10 viral densities, days 0-7) in standardized duplicate oropharyngeal swab eluates, in a modified intention-to-treat population.

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We describe the MalariaGEN Pf7 data resource, the seventh release of genome variation data from the MalariaGEN network.  It comprises over 20,000 samples from 82 partner studies in 33 countries, including several malaria endemic regions that were previously underrepresented.  For the first time we include dried blood spot samples that were sequenced after selective whole genome amplification, necessitating new methods to genotype copy number variations.

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Background: There is no generally accepted methodology for in vivo assessment of antiviral activity in SARS-CoV-2 infections. Ivermectin has been recommended widely as a treatment of COVID-19, but whether it has clinically significant antiviral activity in vivo is uncertain.

Methods: In a multicentre open label, randomized, controlled adaptive platform trial, adult patients with early symptomatic COVID-19 were randomized to one of six treatment arms including high-dose oral ivermectin (600 µg/kg daily for 7 days), the monoclonal antibodies casirivimab and imdevimab (600 mg/600 mg), and no study drug.

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The emergence of artemisinin resistance is a major obstacle to the global malaria eradication/elimination programs. Artemisinin is a very fast-acting antimalarial drug and is the most important drug in the treatment of severe and uncomplicated malaria. For the treatment of acute uncomplicated falciparum malaria, artemisinin derivatives are combined with long half-life partner drugs and widely used as artemisinin-based combination therapies (ACTs).

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Background: Understanding the effect of immunity on Plasmodium falciparum clearance is essential for interpreting therapeutic efficacy studies designed to monitor emergence of artemisinin drug resistance. In low-transmission areas of Southeast Asia, where resistance has emerged, P. falciparum antibodies confound parasite clearance measures.

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This report describes the MalariaGEN Pv4 dataset, a new release of curated genome variation data on 1,895 samples of collected at 88 worldwide locations between 2001 and 2017. It includes 1,370 new samples contributed by MalariaGEN and VivaxGEN partner studies in addition to previously published samples from these and other sources. We provide genotype calls at over 4.

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Rickettsial infections are among the leading etiologies of acute febrile illness in Southeast Asia. However, recent data from Malaysia are limited. This prospective study was conducted in Teluk Intan, Peninsular Malaysia, during January to December 2016.

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Introduction: Understanding the human immune response to gametocytes and its association with gametocytemia is essential for understanding the transmission of malaria as well as progressing transmission blocking vaccine candidates.

Methods: In a multi-national clinical efficacy trial of artemisinin therapies (13 sites of varying transmission over South-East Asia and Africa), we measured Immunoglobulin G (IgG) responses to recombinant gametocyte antigens expressed on the gametocyte plasma membrane and leading transmission blocking vaccine candidates s230 (s230c and s230D1M) and s48/45 at enrolment in 1,114 participants with clinical falciparum malaria. Mixed effects linear and logistic regression were used to determine the association between gametocyte measures (gametocytemia and gametocyte density) and antibody outcomes at enrolment.

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The emergence and spread of artemisinin-resistant Plasmodium falciparum, first in the Greater Mekong Subregion (GMS), and now in East Africa, is a major threat to global malaria elimination ambitions. To investigate the artemisinin resistance mechanism, transcriptome analysis was conducted of 577 P. falciparum isolates collected in the GMS between 2016-2018.

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Artemisinin resistance in Plasmodium falciparum has emerged and spread widely in the Greater Mekong Subregion, threatening current first-line artemisinin combination treatments. New antimalarial drugs are needed urgently. Cipargamin (KAE609) and ganaplacide (KAF156) are promising novel antimalarial compounds in advanced stages of development.

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Background: National Malaria Control Programmes (NMCPs) currently make limited use of parasite genetic data. We have developed GenRe-Mekong, a platform for genetic surveillance of malaria in the Greater Mekong Subregion (GMS) that enables NMCPs to implement large-scale surveillance projects by integrating simple sample collection procedures in routine public health procedures.

Methods: Samples from symptomatic patients are processed by SpotMalaria, a high-throughput system that produces a comprehensive set of genotypes comprising several drug resistance markers, species markers and a genomic barcode.

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Article Synopsis
  • MalariaGEN is a global data-sharing network focused on studying the genomic epidemiology of malaria, releasing new genome variation data from 7,000 samples across 28 malaria-endemic countries.
  • The project generated high-quality genotype data on 3 million single nucleotide polymorphisms (SNPs) and identified drug resistance factors, revealing that nearly all samples showed some genetic resistance to antimalarial drugs.
  • The ongoing expansion of this open data resource aims to enhance research on malaria's evolution and improve tools necessary for malaria surveillance and elimination efforts.
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Background: Mass drug administration (MDA) has received growing interest to accelerate the elimination of multi-drug resistant malaria in the Greater Mekong Subregion. Targeted MDA, sometimes referred to as focal MDA, is the practice of delivering MDA to high incidence subpopulations only, rather than the entire population. The potential effectiveness of delivering targeted MDA was demonstrated in a recent intervention in Kayin State, Myanmar.

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Resistance to artemisinin-based combination therapy (ACT) in the parasite is threatening to reverse recent gains in reducing global deaths from malaria. While resistance manifests as delayed parasite clearance in patients, the phenotype can only spread geographically via the sexual stages and mosquito transmission. In addition to their asexual killing properties, artemisinin and its derivatives sterilize sexual male gametocytes.

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