Plasmodium falciparum Plasmepsin 2 Duplications, West Africa

Dihydroartemisinin/piperaquine (DHA/PPQ) is increasingly deployed as antimalaria drug in Africa. We report the detection in Mali of Plasmodium falciparum infections carrying plasmepsin 2 duplications (associated with piperaquine resistance) in 7/65 recurrent infections within 2 months after DHA/PPQ treatment. These findings raise concerns about the long-term efficacy of DHA/PPQ treatment in Africa.This work was supported by a Swedish Research Council Grant (no. VR-2014-3134). The WANECAM study is funded by the European and Developing Countries Clinical Trial Partnership and by the Medicines for Malaria Venture (Geneva, Switzerland) and is co-funded by the United Kingdom Medical Research Councils, the Swedish International Development Cooperation Agency, the German Ministry for Education and Research, the University Claude Bernard (Lyon, France), the University of Science, Techniques, and Technologies of Bamako (Bamako, Mali), the Centre National de Recherche et de Formation sur le Paludisme (Burkina Faso), the Institut de Recherche en Sciences de la Sante (Bobo-Dioulasso, Burkina Faso), and the Centre National de Formation et de Recherche en Sante Rurale (Guinea).J.I. was supported by EuroInkaNet/Erasmus Mundus Program. Fundacao para a Ciencia e Tecnologia supports M.S. (grant no. SFRH/BD/129769/2017), M.I.V. (grant no. SFRH/BPD/76614/2011), and P.E.F. (grant no. IF/00143/2015)

Efficacy of chloroquine, amodiaquine and sulphadoxine-pyrimethamine for the treatment of uncomplicated falciparum malaria: revisiting molecular markers in an area of emerging AQ and SP resistance in Mali

<p>Abstract</p> <p>Background</p> <p>To update the National Malaria Control Programme of Mali on the efficacy of chloroquine, amodiaquine and sulphadoxine-pyrimethamine in the treatment of uncomplicated <it>falciparum </it>malaria.</p> <p>Methods</p> <p>During the malaria transmission seasons of 2002 and 2003, 455 children – between six and 59 months of age, with uncomplicated malaria in Kolle, Mali, were randomly assigned to one of three treatment arms. <it>In vivo </it>outcomes were assessed using WHO standard protocols. Genotyping of <it>msp1</it>, <it>msp2 </it>and CA1 polymorphisms were used to distinguish reinfection from recrudescent parasites (molecular correction).</p> <p>Results</p> <p>Day 28 adequate clinical and parasitological responses (ACPR) were 14.1%, 62.3% and 88.9% in 2002 and 18.2%, 60% and 85.2% in 2003 for chloroquine, amodiaquine and sulphadoxine-pyrimethamine, respectively. After molecular correction, ACPRs (cACPR) were 63.2%, 88.5% and 98.0% in 2002 and 75.5%, 85.2% and 96.6% in 2003 for CQ, AQ and SP, respectively. Amodiaquine was the most effective on fever. Amodiaquine therapy selected molecular markers for chloroquine resistance, while in the sulphadoxine-pyrimethamine arm the level of <it>dhfr </it>triple mutant and <it>dhfr</it>/<it>dhps </it>quadruple mutant increased from 31.5% and 3.8% in 2002 to 42.9% and 8.9% in 2003, respectively. No infection with <it>dhps </it>540E was found.</p> <p>Conclusion</p> <p>In this study, treatment with sulphadoxine-pyrimethamine emerged as the most efficacious on uncomplicated falciparum malaria followed by amodiaquine. The study demonstrated that sulphadoxine-pyrimethamine and amodiaquine were appropriate partner drugs that could be associated with artemisinin derivatives in an artemisinin-based combination therapy.</p

Differential infectivity of gametocytes after artemisinin-based combination therapy of uncomplicated falciparum malaria

Background: Most malaria-endemic countries use artemisinin-based combination therapy (ACT) as their first-line treatment. ACTs are known to be highly effective on asexual stages of the malaria parasite. Malaria transmission and the spread of resistant parasites depend on the infectivity of gametocytes. The effect of the current ACT regimens on gametocyte infectivity is unclear. Objectives: This study aimed to determine the infectivity of gametocytes to Anopheles gambiae following ACT treatment in the field. Methods: During a randomised controlled trial in Bougoula-Hameau, Mali, conducted from July 2005 to July 2007, volunteers with uncomplicated malaria were randomised to receive artemether-lumefantrine, artesunate-amodiaquine, or artesunate-sulfadoxine/pyrimethamine. Volunteers were followed for 28 days, and gametocyte carriage was assessed. Direct skin feeding assays were performed on gametocyte carriers before and after ACT administration. Results: Following artemether-lumefantrine treatment, gametocyte carriage decreased steadily from Day 0 to Day 21 post-treatment initiation. In contrast, for the artesunate-amodiaquine and artesunate-sulfadoxine/pyrimethamine arms, gametocyte carriage increased on Day 3 and remained constant until Day 7 before decreasing afterward. Mosquito feeding assays showed that artemether-lumefantrine and artesunate-amodiaquine significantly increased gametocyte infectivity to Anopheles gambiae sensu lato (s.l.) (p < 10−4), whereas artesunate-sulfadoxine/pyrimethamine decreased gametocyte infectivity in this setting (p = 0.03). Conclusion: Different ACT regimens could lead to gametocyte populations with different capacity to infect the Anopheles vector. Frequent assessment of the effect of antimalarials on gametocytogenesis and gametocyte infectivity may be required for the full assessment of treatment efficacy, the potential for spread of drug resistance and malaria transmission in the field

Population-specific variations in KCNH2 predispose patients to delayed ventricular repolarization upon dihydroartemisinin-piperaquine therapy

Funding Information: The study was supported by European and Developing Countries Clinical Trial Partnership (grant number RIA2017T-2018), Medicines for Malaria Venture (Geneva, Switzerland), UK Medical Research Council, Swedish International Development Cooperation Agency, German Ministry for Education and Research, University Claude Bernard (Lyon, France), Malaria Research and Training Centre (Bamako, Mali), Centre National de Recherche et de Formation sur le Paludisme (Burkina Faso), Institut de Recherche en Sciences de la Sant. (Bobo-Dioulasso, Burkina Faso), and Centre National de Formation et de Recherche en Sant. Rurale (Republic of Guinea). In addition, the authors received support from the Swedish Research Council (grant numbers 2019-01837, 2021-02801, 2021-05666, and 2021-06048), the Grants, Innovation and Product Development Unit of the South African Medical Research Council with funds received from Novartis and GSK R&D for Project Africa GRADIENT (grant numbers GSKNVS2/202101/004), the Robert Bosch Foundation, Stuttgart, Germany, and Conselho Nacional de Desenvolvimento Cient\u00EDfico e Tecnol\u00F3gico (CNPq), Brazil (grant number 200075/2022\u20135). T.N.S. is a CNPq Research Productivity Fellow. M.D.C. performed sequencing, analyzed the data, and conducted statistical analyses. Y.Z. conducted computational variant analyses. M.M.T. was involved in the acquisition of drug concentrations. A.D. and S.S. contributed to bioinformatics analyses. N.O. was the cardiologist responsible for cardiac toxicity assessment. A.H.T, M.L.A., B.F., and I.S. oversaw clinical patient recruitment and management. A.A.D. coordinated and oversaw the WANECAM study and critically reviewed the manuscript. P.J.G. and V.M.L designed and supervised the study. M.D.C. and V.M.L. wrote the manuscript. All authors read, reviewed, and approved of the final version of the manuscript. Funding Information: The study was supported by European and Developing Countries Clinical Trial Partnership (grant number RIA2017T-2018), Medicines for Malaria Venture (Geneva, Switzerland), UK Medical Research Council, Swedish International Development Cooperation Agency, German Ministry for Education and Research, University Claude Bernard (Lyon, France), Malaria Research and Training Centre (Bamako, Mali), Centre National de Recherche et de Formation sur le Paludisme (Burkina Faso), Institut de Recherche en Sciences de la Sant. (Bobo-Dioulasso, Burkina Faso), and Centre National de Formation et de Recherche en Sant. Rurale (Republic of Guinea). In addition, the authors received support from the Swedish Research Council (grant numbers 2019-01837, 2021-02801, 2021-05666, and 2021-06048), the Grants, Innovation and Product Development Unit of the South African Medical Research Council with funds received from Novartis and GSK R&D for Project Africa GRADIENT (grant numbers GSKNVS2/202101/004), the Robert Bosch Foundation, Stuttgart, Germany, and Conselho Nacional de Desenvolvimento e Tecnol\u00F3gico (CNPq), Brazil (grant number 200075/2022\u20135). T.N.S. is a CNPq Research Productivity Fellow. Publisher Copyright: Copyright © 2024 Camara et al.Dihydroartemisinin-piperaquine is efficacious for the treatment of uncomplicated malaria and its use is increasing globally. Despite the positive results in fighting malaria, inhibition of the Kv11.1 channel (hERG; encoded by the KCNH2 gene) by piperaquine has raised concerns about cardiac safety. Whether genetic factors could modulate the risk of piperaquine-mediated QT prolongations remained unclear. Here, we first profiled the genetic landscape of KCNH2 variability using data from 141,614 individuals. Overall, we found 1,007 exonic variants distributed over the entire gene body, 555 of which were missense. By optimizing the gene-specific parametrization of 16 partly orthogonal computational algorithms, we developed a KCNH2-specific ensemble classifier that identified a total of 116 putatively deleterious missense variations. To evaluate the clinical relevance of KCNH2 variability, we then sequenced 293 Malian patients with uncomplicated malaria and identified 13 variations within the voltage sensing and pore domains of Kv11.1 that directly interact with channel blockers. Cross-referencing of genetic and electrocardiographic data before and after piperaquine exposure revealed that carriers of two common variants, rs1805121 and rs41314375, experienced significantly higher QT prolongations (ΔQTc of 41.8 ms and 61 ms, respectively, vs 14.4 ms in controls) with more than 50% of carriers having increases in QTc >30 ms. Furthermore, we identified three carriers of rare population-specific variations who experienced clinically relevant delayed ventricular repolarization. Combined, our results map population-scale genetic variability of KCNH2 and identify genetic biomarkers for piperaquine-induced QT prolongation that could help to flag at-risk patients and optimize efficacy and adherence to antimalarial therapy.publishersversionpublishe

Different Plasmodium falciparum clearance times in two Malian villages following artesunate monotherapy.

BACKGROUND: Artemisinin resistance described as increased parasite clearance time (PCT) is rare in Africa. More sensitive methods such as qPCR might better characterize the clearance phenotype in sub-Saharan Africa. METHODS: PCT is explored in Mali using light microscopy and qPCR after artesunate for uncomplicated malaria. In two villages, patients were followed for 28 days. Blood smears and spots were collected respectively for microscopy and qPCR. Parasitemia slope half-life was calculated after microscopy. Patient residual parasitemia were measured by qPCR. RESULTS: Uncorrected adequate clinical and parasitological responses (ACPR) observed in Faladje and Bougoula-Hameau were 78% and 92%, respectively (p=0.01). This reached 100% for both after molecular correction. Proportions of 24H microscopy positive patients in Faladje and Bougoula-Hameau were 97.2% and 72%, respectively (p<0.0001). Slope half-life was 2.8h in Faladje vs 2H in Bougoula-Hameau (p<0.001) and Proportions of 72H patients with residual parasitemia were 68.5% and 40% in Faladje and Bougoula-Hameau, respectively (p=0.003). The mean residual parasitemia was 2.9 in Faladje vs. 0.008 in Bougoula-Hameau (p=0.002). Although artesunate is efficacious in Mali, the longer parasite clearance time with submicroscopic parasitemia observed may represent early signs of developing P. falciparum resistance to artemisinins

Declining Trends of Pneumococcal Meningitis in Gambian Children After the Introduction of Pneumococcal Conjugate Vaccines.

BACKGROUND: Acute bacterial meningitis remains a major cause of childhood mortality in sub-Saharan Africa. We document findings from hospital-based sentinel surveillance of bacterial meningitis among children <5 years of age in The Gambia, from 2010 to 2016. METHODS: Cerebrospinal fluid (CSF) was collected from children admitted to the Edward Francis Small Teaching Hospital with suspected meningitis. Identification of Streptococcus pneumoniae (pneumococcus), Neisseria meningitidis (meningococcus), and Haemophilus influenzae was performed by microbiological culture and/or polymerase chain reaction where possible. Whole genome sequencing was performed on pneumococcal isolates. RESULTS: A total of 438 children were admitted with suspected meningitis during the surveillance period. The median age of the patients was 13 (interquartile range, 3-30) months. Bacterial meningitis was confirmed in 21.4% (69/323) of all CSF samples analyzed. Pneumococcus, meningococcus, and H. influenzae accounted for 52.2%, 31.9%, and 16.0% of confirmed cases, respectively. There was a significant reduction of pneumococcal conjugate vaccine (PCV) serotypes, from 44.4% in 2011 to 0.0% in 2014, 5 years after PCV implementation. The majority of serotyped meningococcus and H. influenzae belonged to meningococcus serogroup W (45.5%) and H. influenzae type b (54.5%), respectively. Meningitis pathogens were more frequently isolated during the dry dusty season of the year. Reduced susceptibility to tetracycline, trimethoprim-sulfamethoxazole, and chloramphenicol was observed. No resistance to penicillin was found. CONCLUSIONS: The proportion of meningitis cases due to pneumococcus declined in the post-PCV era. However, the persistence of vaccine-preventable meningitis in children aged <5 years is a major concern and demonstrates the need for sustained high-quality surveillance

Micronutrient Deficiencies, Nutritional Status and the Determinants of Anemia in Children 0-59 Months of Age and Non-Pregnant Women of Reproductive Age in The Gambia.

Data on micronutrient deficiency prevalence, nutrition status, and risk factors of anemia in The Gambia is scanty. To fill this data gap, a nationally representative cross-sectional survey was conducted on 1354 children (0-59 months), 1703 non-pregnant women (NPW; 15-49 years), and 158 pregnant women (PW). The survey assessed the prevalence of under and overnutrition, anemia, iron deficiency (ID), iron deficiency anemia (IDA), vitamin A deficiency (VAD), and urinary iodine concentration (UIC). Multivariate analysis was used to assess risk factors of anemia. Among children, prevalence of anemia, ID, IDA, and VAD was 50.4%, 59.0%, 38.2%, and 18.3%, respectively. Nearly 40% of anemia was attributable to ID. Prevalence of stunting, underweight, wasting, and small head circumference was 15.7%, 10.6%, 5.8%, and 7.4%, respectively. Among NPW, prevalence of anemia, ID, IDA and VAD was 50.9%, 41.4%, 28.0% and 1.8%, respectively. Anemia was significantly associated with ID and vitamin A insufficiency. Median UIC in NPW and PW was 143.1 µg/L and 113.5 ug/L, respectively. Overall, 18.3% of NPW were overweight, 11.1% obese, and 15.4% underweight. Anemia is mainly caused by ID and poses a severe public health problem. To tackle both anemia and ID, programs such as fortification or supplementation should be intensified

Prevalence and co-existence of cardiometabolic risk factors and associations with nutrition-related and socioeconomic indicators in a national sample of Gambian women.

Cardiovascular diseases (CVD) are on the rise in Sub-Saharan Africa, and a large proportion of the adult population is thought to suffer from at least one cardiometabolic risk factor. This study assessed cardiometabolic risk factors and the contribution of nutrition-related indicators in Gambian women. The prevalence and co-existence of diabetes (elevated glycated hemoglobin (HbA1c ≥ 6.5%) or prediabetes (HbA1c ≥ 5.7% to  3 mg/L or alpha-1-acid glycoprotein (AGP) > 1 g/L) and the contribution of nutrition related and socioeconomic indicators were measured in non-pregnant women 15-49 years of age in the Gambia using data from a nationally representative cross-sectional stratified survey. Nationally, 54.5% (95% CI: 47.4, 61.4) of 1407 women had elevated HbA1c. Of these, 14.9% were diabetic and 85.1% were prediabetic. Moreover, 20.8% (95% CI 17.8, 20.0) of 1685 women had hypertension, 11.1% (95% CI 9.0, 13.7) of 1651 were obese and 17.2% (95% CI 5.1, 19.6) of 1401 had inflammation. At least one of the aforementioned cardiometabolic risk factor was present in 68.3% (95% CI 63.0, 73.1) of women. Obesity increased the risk of hypertension (aRR 1.84; 95% CI 1.40, 2.41), diabetes (aRR 1.91; 95% CI 1.29, 2.84), elevated HbA1c (aRR 1.31; 95% CI 1.14, 1.51) and inflammation (aRR 3.47; 95% CI 2.61, 4.61). Inflammation increased the risk of hypertension (aRR 1.42; 95% CI 1.14, 1.78). Aging increased the risk of hypertension, obesity and inflammation. Further, inadequate sanitation increased the risk for diabetes (aRR 1.65; 95% CI 1.17, 2.34) and iron deficiency increased the risk of elevated HbA1c (aRR 1.21; 95% CI 1.09, 1.33). The high prevalence of cardiometabolic risk factors and their co-existence in Gambian women is concerning. Although controlling obesity seems to be key, multifaceted strategies to tackle the risk factors separately are warranted to reduce the prevalence or minimize the risk of CVD

Hepatic safety and tolerability of cipargamin (KAE609), in adult patients with Plasmodium falciparum malaria: a randomized, phase II, controlled, dose-escalation trial in sub-Saharan Africa.

BACKGROUND: The novel anti-malarial cipargamin (KAE609) has potent, rapid activity against Plasmodium falciparum. Transient asymptomatic liver function test elevations were previously observed in cipargamin-treated subjects in two trials: one in malaria patients in Asia and one in volunteers with experimentally induced malaria. In this study, the hepatic safety of cipargamin given as single doses of 10 to 150 mg and 10 to 50 mg once daily for 3 days was assessed. Efficacy results, frequency of treatment-emerging mutations in the atp4 gene and pharmacokinetics have been published elsewhere. Further, the R561H mutation in the k13 gene, which confers artemisinin-resistance, was associated with delayed parasite clearance following treatment with artemether-lumefantrine in Rwanda in this study. This was also the first study with cipargamin to be conducted in patients in sub-Saharan Africa. METHODS: This was a Phase II, multicentre, randomized, open-label, dose-escalation trial in adults with uncomplicated falciparum malaria in five sub-Saharan countries, using artemether-lumefantrine as control. The primary endpoint was ≥ 2 Common Terminology Criteria for Adverse Events (CTCAE) Grade increase from baseline in alanine aminotransferase (ALT) or aspartate transaminase (AST) during the 4-week trial. RESULTS: Overall, 2/135 patients treated with cipargamin had ≥ 2 CTCAE Grade increases from baseline in ALT or AST compared to 2/51 artemether-lumefantrine patients, with no significant difference between any cipargamin treatment group and the control group. Cipargamin exposure was comparable to or higher than those in previous studies. Hepatic adverse events and general safety and tolerability were similar for all cipargamin doses and artemether-lumefantrine. Cipargamin was well tolerated with no safety concerns. CONCLUSIONS: This active-controlled, dose escalation study was a detailed assessment of the hepatic safety of cipargamin, across a wide range of doses, in patients with uncomplicated falciparum malaria. Comparison with previous cipargamin trials requires caution as no clear conclusion can be drawn as to whether hepatic safety and potential immunity to malaria would differ with ethnicity, patient age and or geography. Previous concerns regarding hepatic safety may have been confounded by factors including malaria itself, whether natural or experimental infection, and should not limit the further development of cipargamin. Trial registration ClinicalTrials.gov number: NCT03334747 (7 Nov 2017), other study ID CKAE609A2202

Efficacy of Cipargamin (KAE609) in a Randomized, Phase II Dose-Escalation Study in Adults in Sub-Saharan Africa With Uncomplicated Plasmodium falciparum Malaria.

BACKGROUND: Cipargamin (KAE609) is a potent antimalarial in a phase II trial. Here we report efficacy, pharmacokinetics, and resistance marker analysis across a range of cipargamin doses. These were secondary endpoints from a study primarily conducted to assess the hepatic safety of cipargamin (hepatic safety data are reported elsewhere). METHODS: This phase II, multicenter, randomized, open-label, dose-escalation trial was conducted in sub-Saharan Africa in adults with uncomplicated Plasmodium falciparum malaria. Cipargamin monotherapy was given as single doses up to 150 mg or up to 50 mg once daily for 3 days, with artemether-lumefantrine as control. Key efficacy endpoints were parasite clearance time (PCT), and polymerase chain reaction (PCR)-corrected and uncorrected adequate clinical and parasitological response (ACPR) at 14 and 28 days. Pharmacokinetics and molecular markers of drug resistance were also assessed. RESULTS: All single or multiple cipargamin doses ≥50 mg were associated with rapid parasite clearance, with median PCT of 8 hours versus 24 hours for artemether-lumefantrine. PCR-corrected ACPR at 14 and 28 days was >75% and 65%, respectively, for each cipargamin dose. A treatment-emerging mutation in the Pfatp4 gene, G358S, was detected in 65% of treatment failures. Pharmacokinetic parameters were consistent with previous data, and approximately dose proportional. CONCLUSIONS: Cipargamin, at single doses of 50 to 150 mg, was associated with very rapid parasite clearance, PCR-corrected ACPR at 28 days of >65% in adults with uncomplicated P. falciparum malaria, and recrudescent parasites frequently harbored a treatment-emerging mutation. Cipargamin will be further developed with a suitable combination partner. CLINICAL TRIALS REGISTRATION: ClinicalTrials.gov (NCT03334747)