Prospective Clinical Trial Assessing Species-Specific Efficacy of Artemether-Lumefantrine for the Treatment of Plasmodium malariae, Plasmodium ovale, and Mixed Plasmodium Malaria in Gabon.
ABSTRACT: Treatment recommendations for Plasmodium malariae and Plasmodium ovale malaria are largely based on anecdotal evidence. The aim of this prospective study, conducted in Gabon, was to systematically assess the efficacy and safety of artemether-lumefantrine for the treatment of patients with uncomplicated P. malariae or P. ovale species monoinfections or mixed Plasmodium infections. Patients with microscopically confirmed P. malariae, P. ovale, or mixed-species malaria with at least one of these two Plasmodium species were treated with an oral, fixed-dose combination of artemether-lumefantrine for 3 consecutive days. The primary endpoints were per-protocol PCR-corrected adequate clinical and parasitological response (ACPR) on days 28 and 42. Tolerability and safety were recorded throughout the follow-up period. Seventy-two participants (42 male and 30 female) were enrolled; 62.5% of them had PCR-corrected mixed Plasmodium infections. Per protocol, PCR-corrected ACPR rates were 96.6% (95% confidence interval [CI], 91.9 to 100) on day 28 and 94.2% (95% CI, 87.7 to 100) on day 42. Considering Plasmodium species independently from their coinfecting species, day 42 ACPR rates were 95.5% (95% CI, 89.0 to 100) for P. falciparum, 100% (exact CI, 84.6 to 100) for P. malariae, 100% (exact CI, 76.8 to 100) for P. ovale curtisi, and 90.9% (95% CI, 70.7 to 100) for P. ovale wallikeri Study drug-related adverse events were generally mild or moderate. In conclusion, this clinical trial demonstrated satisfying antimalarial activity of artemether-lumefantrine against P. ovalewallikeri, P. ovale curtisi, P. malariae, and mixed Plasmodium infections, with per-protocol efficacies of 90% to 100% and without evident tolerability or safety concerns. (This trial was registered in the clinical study database ClinicalTrials.gov under the identifier NCT02528279.).
Project description:The recommendation of artemisinin combination therapy (ACT) as first-line treatment for uncomplicated falciparum malaria is supported by a plethora of high quality clinical trials. However, their recommendation for the treatment of mixed-species malaria and the large-scale use for the treatment of non-falciparum malaria in endemic regions is based on anecdotal rather than systematic clinical evidence.This study prospectively observed the efficacy of artemether-lumefantrine for the treatment of uncomplicated non-falciparum or mixed-species malaria in two routine district hospitals in the Central African country of Gabon.Forty patients suffering from uncomplicated Plasmodium malariae, Plasmodium ovale or mixed-species malaria (including Plasmodium falciparum) presenting at the hospital received artemether-lumefantrine treatment and were followed up. All evaluable patients (n=38) showed an adequate clinical and parasitological response on Day 28 after oral treatment with artemether-lumefantrine (95% confidence interval: 0.91,1). All adverse events were of mild to moderate intensity and completely resolved by the end of study.This first systematic assessment of artemether-lumefantrine treatment for P. malariae, P. ovale and mixed-species malaria demonstrated a high cure rate of 100% and a favourable tolerability profile, and thus lends support to the practice of treating non-falciparum or mixed-species malaria, or all cases of malaria without definite species differentiation, with artemether-lumefantrine in Gabon.ClinicalTrials.gov Identifier: NCT00725777.
Project description:<h4>Background</h4>Plasmodium ovale curtisi and wallikeri are perceived as relapsing malarial parasites. Contrary to Plasmodium vivax, direct evidence for this hypothesis is scarce. The aim of this prospective study was to characterize the reappearance patterns of ovale parasites.<h4>Methods</h4>P. ovale spp. infected patients were treated with artemether-lumefantrine and followed biweekly for up to 1 year for the detection of reappearing parasitemia. Molecular analysis of reappearing isolates was performed to identify homologous isolates by genotyping and to define cases of relapse following predefined criteria.<h4>Results</h4>At inclusion, 26 participants were positive for P. ovale curtisi and/or P. ovale wallikeri. The median duration of follow-up was 35 weeks. Reappearance of the same P. ovale species was observed in 46% of participants; 61% of P. ovale curtisi and 19% of P. ovale wallikeri infection-free intervals were estimated to end with reappearance by week 32. Based on the predefined criteria, 23% of participants were identified with 1 or 2 relapses, all induced by P. ovale curtisi.<h4>Conclusion</h4>These findings are in line with the currently accepted relapse theory inasmuch as the reappearance of P. ovale curtisi strains following initial blood clearance was conclusively demonstrated. Interestingly, no relapse of P. ovale wallikeri was observed.
Project description:Microsatellites can be utilized to explore genotypes, population structure, and other genomic features of eukaryotes. Systematic characterization of microsatellites has not been a focus for several species of Plasmodium, including P. malariae and P. ovale, as the majority of malaria elimination programs are focused on P. falciparum and to a lesser extent P. vivax. Here, five human malaria species (P. falciparum, P. vivax, P. malariae, P. ovale curtisi, and P. knowlesi) were investigated with the aim of conducting in-depth categorization of microsatellites for P. malariae and P. ovale curtisi. Investigation of reference genomes for microsatellites with unit motifs of 1-10 base pairs indicates high diversity among the five Plasmodium species. Plasmodium malariae, with the largest genome size, displays the second highest microsatellite density (1421 No./Mbp; 5% coverage) next to P. falciparum (3634 No./Mbp; 12% coverage). The lowest microsatellite density was observed in P. vivax (773 No./Mbp; 2% coverage). A, AT, and AAT are the most commonly repeated motifs in the Plasmodium species. For P. malariae and P. ovale curtisi, microsatellite-related sequences are observed in approximately 18-29% of coding sequences (CDS). Lysine, asparagine, and glutamic acids are most frequently coded by microsatellite-related CDS. The majority of these CDS could be related to the gene ontology terms "cell parts," "binding," "developmental processes," and "metabolic processes." The present study provides a comprehensive overview of microsatellite distribution and can assist in the planning and development of potentially useful genetic tools for further investigation of P. malariae and P. ovale curtisi epidemiology.
Project description:BACKGROUND: In Ethiopia Plasmodium falciparum and Plasmodium vivax are the dominant species accounting for roughly 60 and 40% of malaria cases, respectively. Recently a major shift from P. falciparum to P. vivax has been observed in various parts of the country but the epidemiology of the other human malaria species, Plasmodium ovale spp. and Plasmodium malariae remains poorly understood. The aim of this study was to assess P. ovale curtisi and wallikeri infection in north-west Ethiopia by using microscopy and nested PCR. METHODS: A health institution-based survey using non-probability sampling techniques was conducted at Maksegnet, Enfranze and Kola Diba health centres and Metema hospital in North Gondar. Three-hundred patients with signs and symptoms consistent with malaria were included in this study and capillary blood was collected for microscopic examination and molecular analysis of Plasmodium species. Samples were collected on Whatman 903 filter papers, stored in small plastic bags with desiccant and transported to Vienna (Austria) for molecular analysis. Data from study participants were entered and analysed by SPSS 20 software. RESULTS: Out of 300 study participants (167 males and 133 females), 184 samples were classified positive for malaria (133 P. falciparum and 51 P. vivax) by microscopy. By species-specific PCR 233 Plasmodium spp (95% CI: 72.6-82) were detected and the majority 155 (66.5%, 95% CI: 60.2-72.3) were P. falciparum followed by P. vivax 69 (29.6%, 95% CI; 24.1-35.8) and 9 (3.9%, 95% CI: 2-7.2) samples were positive for P. ovale. Seven of P. ovale parasites were confirmed as P. ovale wallikeri and two were confirmed as P. ovale curtisi. None of the samples tested positive for P. malariae. During microscopic examination there were high (16.3%) false negative reports and all mixed infections and P. ovale cases were missed or misclassified. CONCLUSION: This study indicates that P. ovale malaria is under-reported in Ethiopia and provides the first known evidence of the sympatric distribution of indigenous P. ovale wallikeri and P. ovale curtisi in Ethiopia. Therefore, further studies assessing the prevalence of the rare species P. ovale and P. malariae are urgently needed to better understand the species distribution and to adapt malaria control strategies.
Project description:Six Plasmodium species are known to naturally infect humans. Mixed species infections occur regularly but morphological discrimination by microscopy is difficult and multiplicity of infection (MOI) can only be evaluated by molecular methods. This study investigated the complexity of Plasmodium infections in patients treated for microscopically detected non-falciparum or mixed species malaria in Gabon.Ultra-deep sequencing of nucleus (18S rRNA), mitochondrion, and apicoplast encoded genes was used to evaluate Plasmodium species diversity and MOI in 46 symptomatic Gabonese patients with microscopically diagnosed non-falciparum or mixed species malaria.Deep sequencing revealed a large complexity of confections in patients with uncomplicated malaria, both on species and genotype levels. Mixed infections involved up to four parasite species (Plasmodium falciparum, Plasmodium malariae, Plasmodium ovale curtisi, and P. ovale wallikeri). Multiple genotypes from each species were determined from the asexual 18S rRNA gene. 17 of 46 samples (37%) harboured multiple genotypes of at least one Plasmodium species. The number of genotypes per sample (MOI) was highest in P. malariae (n = 4), followed by P. ovale curtisi (n = 3), P. ovale wallikeri (n = 3), and P. falciparum (n = 2). The highest combined genotype complexity in samples that contained mixed-species infections was seven.Ultra-deep sequencing showed an unexpected breadth of Plasmodium species and within species diversity in clinical samples. MOI of P. ovale curtisi, P. ovale wallikeri and P. malariae infections were higher than anticipated and contribute significantly to the burden of malaria in Gabon.
Project description:<h4>Background</h4>Artemisinin combination therapies (ACTs) with broad efficacy are needed where multiple Plasmodium species are transmitted, especially in children, who bear the brunt of infection in endemic areas. In Papua New Guinea (PNG), artemether-lumefantrine is the first-line treatment for uncomplicated malaria, but it has limited efficacy against P. vivax. Artemisinin-naphthoquine should have greater activity in vivax malaria because the elimination of naphthoquine is slower than that of lumefantrine. In this study, the efficacy, tolerability, and safety of these ACTs were assessed in PNG children aged 0.5-5 y.<h4>Methods and findings</h4>An open-label, randomized, parallel-group trial of artemether-lumefantrine (six doses over 3 d) and artemisinin-naphthoquine (three daily doses) was conducted between 28 March 2011 and 22 April 2013. Parasitologic outcomes were assessed without knowledge of treatment allocation. Primary endpoints were the 42-d P. falciparum PCR-corrected adequate clinical and parasitologic response (ACPR) and the P. vivax PCR-uncorrected 42-d ACPR. Non-inferiority and superiority designs were used for falciparum and vivax malaria, respectively. Because the artemisinin-naphthoquine regimen involved three doses rather than the manufacturer-specified single dose, the first 188 children underwent detailed safety monitoring. Of 2,542 febrile children screened, 267 were randomized, and 186 with falciparum and 47 with vivax malaria completed the 42-d follow-up. Both ACTs were safe and well tolerated. P. falciparum ACPRs were 97.8% and 100.0% in artemether-lumefantrine and artemisinin-naphthoquine-treated patients, respectively (difference 2.2% [95% CI -3.0% to 8.4%] versus -5.0% non-inferiority margin, p = 0.24), and P. vivax ACPRs were 30.0% and 100.0%, respectively (difference 70.0% [95% CI 40.9%-87.2%], p<0.001). Limitations included the exclusion of 11% of randomized patients with sub-threshold parasitemias on confirmatory microscopy and direct observation of only morning artemether-lumefantrine dosing.<h4>Conclusions</h4>Artemisinin-naphthoquine is non-inferior to artemether-lumefantrine in PNG children with falciparum malaria but has greater efficacy against vivax malaria, findings with implications in similar geo-epidemiologic settings within and beyond Oceania.<h4>Trial registration</h4>Australian New Zealand Clinical Trials Registry ACTRN12610000913077. Please see later in the article for the Editors' Summary.
Project description:BACKGROUND:Malaria caused by Plasmodium ovale spp. has been neglected by and large from research and has received only little scientific attention during the past decades. Ovale malaria is considered to feature relapses by liver hypnozoites although scientific evidence for this paradigm is scarce. CASE PRESENTATION:Here, the case of a 16-year-old male, who presented with fevers to the outpatient department in Vienna, Austria, after travelling to Uganda and Papua New Guinea is described. Infection with Plasmodium malariae was diagnosed by microscopy and the patient was treated accordingly with a full course of supervised artemether-lumefantrine. He was discharged in good clinical condition with a negative blood smear. One month after initial diagnosis, he returned complaining of fever. Thick blood smear was positive again for malaria parasites, which were confirmed as P. ovale wallikeri by PCR. Retrospective analysis revealed the identical Plasmodium spp. in the initial blood samples. Molecular analysis of various gene loci (nuclear porbp2, 18S rRNA and potra genes) gave identical results providing further evidence for relapse by an identical parasite genotype. Consecutively, the patient was retreated with artemether-lumefantrine and received a regimen of primaquine according to WHO guidelines. CONCLUSION:Conclusive evidence for relapses with P. ovale spp. is rare. The presented case provides convincing confirmation for the relapse paradigm based on re-appearing parasitaemia following supervised treatment in a non-endemic region with a parasite strain of identical genotype.
Project description:Background:We assessed the efficacy of artemisinin-based combination therapies for treatment of uncomplicated falciparum malaria, with or without co-infecting Plasmodium spp., in Sumatera, Indonesia. Methods:Febrile patients aged >6 months with uncomplicated P. falciparum were randomized to receive dihydroartemisinin-piperaquine or artemether-lumefantrine, plus single-dose primaquine, and were followed for 42 days. Mixed Plasmodium infections were included; P. vivax infections received 14 days of primaquine. We retrospectively restricted the analysis to cases with polymerase chain reaction (PCR)-confirmed parasitemia. Recurrent parasitemia in follow-up was identified by species-specific nested PCR. Results:Of the 3731 participants screened, 302 were enrolled and randomized. In the dihydroartemisinin-piperaquine arm, P. falciparum infections were confirmed by PCR in 59 participants, with mixed infections in 23 (39.0%). In the artemether-lumefantrine arm, P. falciparum infections were confirmed by PCR in 55 participants, with mixed infections in 16 (29.0%). Both regimens were well tolerated, and symptoms improved rapidly in all treated participants. In the dihydroartemisinin-piperaquine arm, 1 P. falciparum recurrence (on day 7) and 6 P. malariae recurrences (1 had a mixed infection with P. falciparum) were identified during days 3-42 of follow-up. In the artemether-lumefantrine arm, 1 P. falciparum/P. malariae/P. vivax recurrence occurred on day 35. Submicroscopic persistence occurred during follow-up in 21 (37%) of 57 receiving dihydroartemisinin-piperaquine and 20 (39%) of 51 receiving artemether-lumefantrine. Conclusions:In Sumatera, both regimens effectively cleared initial parasitemia, but P. falciparum and P. malariae persisted in some individuals. Molecular species detection should be deployed in antimalarial efficacy trials in Indonesia. Trial registration:NCT02325180.
Project description:Children are most vulnerable to malaria. A pyronaridine-artesunate pediatric granule formulation is being developed for the treatment of uncomplicated Plasmodium falciparum malaria.This phase III, multi-center, comparative, open-label, parallel-group, controlled clinical trial included patients aged ?12 years, bodyweight ?5 to <25 kg, with a reported history of fever at inclusion or in the previous 24 h and microscopically-confirmed uncomplicated P. falciparum malaria. Patients were randomized (2:1) to pyronaridine-artesunate granules (60/20 mg) once daily or artemether-lumefantrine crushed tablets (20/120 mg) twice daily, both dosed by bodyweight, orally (liquid suspension) for three days.Of 535 patients randomized, 355 received pyronaridine-artesunate and 180 received artemether-lumefantrine. Day-28 adequate clinical and parasitological response (ACPR), corrected for re-infection using polymerase chain reaction (PCR) genotyping (per-protocol population) was 97.1% (329/339; 95% CI 94.6, 98.6) for pyronaridine-artesunate; 98.8% (165/167; 95% CI 95.7, 99.9) for artemether-lumefantrine. The primary endpoint was achieved: pyronaridine-artesunate PCR-corrected day-28 ACPR was statistically significantly >90% (P < .0001). Pyronaridine-artesunate was non-inferior to artemether-lumefantrine: treatment difference -1.8% (95% CI -4.3 to 1.6). The incidence of drug-related adverse events was 37.2% (132/355) with pyronaridine-artesunate, 44.4% (80/180) with artemether-lumefantrine. Clinical biochemistry results showed similar mean changes versus baseline in the two treatment groups. From day 3 until study completion, one patient in each treatment group had peak alanine aminotransferase (ALT) >3 times the upper limit of normal (ULN) and peak total bilirubin >2xULN (i.e. within the Hy's law definition).The pyronaridine-artesunate pediatric granule formulation was efficacious and was non-inferior to artemether-lumefantrine. The adverse event profile was similar for the two comparators. Pyronaridine-artesunate should be considered for inclusion in paediatric malaria treatment programmes.ClinicalTrials.gov: identifier NCT00541385.
Project description:BACKGROUND:In 2009, the Papua New Guinea (PNG) Department of Health adopted artemether-lumefantrine (AL) and dihydroartemisinin-piperaquine (DHA-PPQ) as the first- and second-line treatments for uncomplicated malaria, respectively. This study was conducted to assess the efficacy of both drugs following adoption of the new policy. METHODS:Between June 2012 and September 2014, a therapeutic efficacy study was conducted in East Sepik and Milne Bay Provinces of PNG in accordance with the standard World Health Organization (WHO) protocol for surveillance of anti-malarial drug efficacy. Patients???6 months of age with microscopy confirmed Plasmodium falciparum or Plasmodium vivax mono-infections were enrolled, treated with AL or DHA-PPQ, and followed up for 42 days. Study endpoints were adequate clinical and parasitological response (ACPR) on days 28 and 42. The in vitro efficacy of anti-malarials and the prevalence of selected molecular markers of resistance were also determined. RESULTS:A total of 274 P. falciparum and 70 P. vivax cases were enrolled. The day-42 PCR-corrected ACPR for P. falciparum was 98.1% (104/106) for AL and 100% (135/135) for DHA-PPQ. The day-42 PCR-corrected ACPR for P. vivax was 79.0% (15/19) for AL and 92.3% (36/39) for DHA-PPQ. Day 3 parasite clearance of P. falciparum was 99.2% with AL and 100% with DHA-PPQ. In vitro testing of 96 samples revealed low susceptibility to chloroquine (34% of samples above IC50 threshold) but not to lumefantrine (0%). Molecular markers assessed in a sub-set of the study population indicated high rates of chloroquine resistance in P. falciparum (pfcrt SVMNT: 94.2%, n?=?104) and in P. vivax (pvmdr1 Y976F: 64.8%, n?=?54). CONCLUSIONS:AL and DHA-PPQ were efficacious as first- and second-line treatments for uncomplicated malaria in PNG. Continued in vivo efficacy monitoring is warranted considering the threat of resistance to artemisinin and partner drugs in the region and scale-up of artemisinin-based combination therapy in PNG.