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The Lancet. Global Health Mar 2024Seasonal malaria chemoprevention (SMC) is recommended for disease control in settings with moderate to high Plasmodium falciparum transmission and currently depends on...
BACKGROUND
Seasonal malaria chemoprevention (SMC) is recommended for disease control in settings with moderate to high Plasmodium falciparum transmission and currently depends on the administration of sulfadoxine-pyrimethamine plus amodiaquine. However, poor regimen adherence and the increased frequency of parasite mutations conferring sulfadoxine-pyrimethamine resistance might threaten the effectiveness of SMC. Guidance is needed to de-risk the development of drug compounds for malaria prevention. We aimed to provide guidance for the early prioritisation of new and alternative SMC drugs and their target product profiles.
METHODS
In this modelling study, we combined an individual-based malaria transmission model that has explicit parasite growth with drug pharmacokinetic and pharmacodynamic models. We modelled SMC drug attributes for several possible modes of action, linked to their potential public health impact. Global sensitivity analyses identified trade-offs between drug elimination half-life, maximum parasite killing effect, and SMC coverage, and optimisation identified minimum requirements to maximise malaria burden reductions.
FINDINGS
Model predictions show that preventing infection for the entire period between SMC cycles is more important than drug curative efficacy for clinical disease effectiveness outcomes, but similarly important for impact on prevalence. When children younger than 5 years receive four SMC cycles with high levels of coverage (ie, 69% of children receiving all cycles), drug candidates require a duration of protection half-life higher than 23 days (elimination half-life >10 days) to achieve reductions higher than 75% in clinical incidence and severe disease (measured over the intervention period in the target population, compared with no intervention across a range of modelled scenarios). High coverage is crucial to achieve these targets, requiring more than 60% of children to receive all SMC cycles and more than 90% of children to receive at least one cycle regardless of the protection duration of the drug.
INTERPRETATION
Although efficacy is crucial for malaria prevalence reductions, chemoprevention development should select drug candidates for their duration of protection to maximise burden reductions, with the duration half-life determining cycle timing. Explicitly designing or selecting drug properties to increase community uptake is paramount.
FUNDING
Bill & Melinda Gates Foundation and the Swiss National Science Foundation.
Topics: Child; Humans; Infant; Antimalarials; Pharmaceutical Preparations; Public Health; Seasons; Malaria; Drug Combinations; Chemoprevention
PubMed: 38365418
DOI: 10.1016/S2214-109X(23)00550-8 -
MedRxiv : the Preprint Server For... Feb 2024Artemisinin-based combination therapies (ACTs) are the recommended antimalarial drugs for the treatment of uncomplicated malaria. The recent emergence of artemisinin...
BACKGROUND
Artemisinin-based combination therapies (ACTs) are the recommended antimalarial drugs for the treatment of uncomplicated malaria. The recent emergence of artemisinin partial resistance (ART-R) in Rwanda, Uganda and Eritrea is of great concern. In Tanzania, a nationwide molecular malaria surveillance in 2021 showed a high prevalence of the Kelch13 (K13) 561H mutation in from the north-western region, close to the border with Rwanda and Uganda. This study was conducted in 2022 to evaluate the efficacy of artemether-lumefantrine (AL) and artesunate-amodiaquine (ASAQ) for the treatment of uncomplicated falciparum malaria and to confirm the presence of ART-R in Tanzania.
METHODS
This single-arm study evaluated the efficacy of AL and ASAQ in eligible children aged six months to 10 years at Bukangara Dispensary in Karagwe District, Kagera Region. Clinical and parasitological responses were monitored for 28 days according to standard WHO protocol. Mutations in K13 gene and extended haplotypes with these mutations were analysed using Sanger and whole genome sequencing data, respectively.
FINDINGS
176 children (88 in each AL and ASAQ group) were enrolled and all achieved the defined outcomes. PCR-corrected adequate clinical and parasitological response (ACPR) was 98.3% (95% CI: 90.8-100) and 100.0% (95% CI: 95.8-100) for AL and ASAQ, respectively. Parasitaemia on day 3 was observed in 11/88 (12.5%) and 17/88 (19.3%) in the AL and ASAQ groups, respectively. The half-life of parasitaemia was significantly higher (>6.5 hrs) in patients with parasitaemia on day 3 and/or mutations in K13 gene at enrolment. Most patients with parasitaemia on day 3 (8/11 = 72.7% in the AL group and 10/17 = 58.8% in the ASAQ group) had 561H mutation at enrolment. The parasites with K13 mutations were not similar to those from south-east Asia and Rwanda, but had the same core haplotype of a new 561H haplotype reported in Kagera in 2021.
INTERPRETATION
These findings confirm the presence of ART-R in Tanzania. A context-specific strategy to respond to artemisinin partial resistance is urgently needed. Although both AL and ASAQ showed high efficacy, increased vigilance for reduced efficacy of these ACTs and detection of ART-R in other parts of the country is critical.
PubMed: 38352311
DOI: 10.1101/2024.01.31.24301954 -
BMC Complementary Medicine and Therapies Feb 2024Chemotherapies target the PfEMP-1 and PfPKG proteins in Plasmodium falciparum, the parasite that causes malaria, in an effort to prevent the disease's high...
BACKGROUND
Chemotherapies target the PfEMP-1 and PfPKG proteins in Plasmodium falciparum, the parasite that causes malaria, in an effort to prevent the disease's high fatality rate. This work identified the phytochemical components of Nauclea latifolia roots and docked the chemical compounds against target proteins, and examined the in vivo antiplasmodial effect of the roots on Plasmodium berghei-infected mice.
METHODS
Standard protocols were followed for the collection of the plant's roots, cleaning, and drying of the roots, extraction and fraction preparation, assessment of the in vivo antiplasmodial activity, retrieval of the PfEMP-1 and PfPKG proteins, GCMS, ADME, and docking studies, chromatographic techniques were employed to separate the residual fraction's components, and the Swis-ADME program made it possible to estimate the drug's likeness and pharmacokinetic properties. The Auto Dock Vina 4.2 tool was utilized for molecular docking analysis.
RESULTS
The residual fraction showed the best therapeutic response when compared favorably to amodiaquine (80.5%) and artesunate (85.1%). It also considerably reduced the number of parasites, with the % growth inhibition of the parasite at 42.8% (D2) and 83.4% (D5). Following purification, 25 compounds were isolated and characterized with GCMS. Based on their low molecular weights, non-permeation of the blood-brain barrier, non-inhibition of metabolizing enzymes, and non-violation of Lipinski's criteria, betulinic and ursolic acids were superior to chloroquine as the best phytochemicals. Hence, they are lead compounds.
CONCLUSION
In addition to identifying the bioactive compounds, ADME, and docking data of the lead compounds as candidates for rational drug design processes as observed against Plasmodium falciparum target proteins (PfEMP-1 and PfPKG), which are implicated in the pathogenesis of malaria, the study has validated that the residual fraction of N. latifolia roots has the best antiplasmodial therapeutic index.
Topics: Mice; Animals; Antimalarials; Ursolic Acid; Molecular Docking Simulation; Plant Extracts; Malaria; Triterpenes; Plasmodium falciparum; Rubiaceae
PubMed: 38326823
DOI: 10.1186/s12906-023-04324-x -
Organic Process Research & Development Jan 2024A robust process for the manufacture of the active pharmaceutical ingredient (API) amodiaquine dihydrochloride dihydrate (ADQ, ), an important antimalarial, is reported....
A robust process for the manufacture of the active pharmaceutical ingredient (API) amodiaquine dihydrochloride dihydrate (ADQ, ), an important antimalarial, is reported. The process consists of a three-step synthetic route that involves a Mannich reaction, substitution with 4,7-dichloroquinoline (4,7-DCQ, ), and rehydration. Additionally, a cost-competitive process for the production of 4,7-DCQ () is also reported wherein 4,7-DCQ () was prepared in four steps from -chloroaniline (). 4-Acetamido-2-(diethylaminomethyl)phenol (), 4,7-DCQ (), and ADQ () were obtained in yields of 92, 89, and 90%, respectively. Costing and process mass intensities of 4,7-DCQ and ADQ are also reported.
PubMed: 38268771
DOI: 10.1021/acs.oprd.3c00205 -
Malaria Journal Jan 2024Seasonal malaria chemoprevention (SMC) is an effective intervention to prevent malaria in children in locations where the burden of malaria is high and transmission is...
BACKGROUND
Seasonal malaria chemoprevention (SMC) is an effective intervention to prevent malaria in children in locations where the burden of malaria is high and transmission is seasonal. There is growing evidence suggesting that SMC with sulfadoxine-pyrimethamine and amodiaquine can retain its high level of effectiveness in East and Southern Africa despite resistance concerns. This study aims to generate evidence on the effectiveness of SMC when delivered under programmatic conditions in an area with an unknown anti-malarial drug resistance profile in the Northern Bahr el-Ghazal region of South Sudan.
METHODS
A non-randomized quasi experimental study was conducted to compare an intervention county with a control county. Five monthly SMC cycles were delivered between July and November 2022, targeting about 19,000 children 3-59 months old. Data were obtained from repeated cross-sectional household surveys of caregivers of children aged 3-59 months using cluster sampling. Wave 1 survey took place in both counties before SMC implementation; Waves 2 and 3 took place after the second and fourth monthly SMC cycles. Difference-in-differences analyses were performed by fitting logistic regression models with interactions between county and wave.
RESULTS
A total of 2760 children were sampled in the study across the three survey waves in both study counties. Children in the intervention arm had 70% lower odds of caregiver-reported fever relative to those in the control arm during the one-month period prior to Wave 2 (OR: 0.30, 95% CI 0.12-0.70, p = 0.003), and 37% lower odds in Wave 3 (OR: 0.63, 95% CI 0.22-1.59, p = 0.306) after controlling for baseline difference between counties in Wave 1. Odds of caregiver-reported RDT-confirmed malaria were 82% lower in the previous 1-month period prior to Wave 2 (OR: 0.18, 95% CI 0.07-0.49, p = 0.001) and Wave 3 (OR: 0.18, 95% CI 0.06-0.54, p = 0.003).
CONCLUSION
These results show high effectiveness of SMC using SPAQ in terms of reducing malaria disease during the high transmission season in children 3-59 month. Despite the promising results, additional evidence and insights from chemoprevention efficacy cohort studies, and analyses of relevant resistance markers, are required to assess the suitability of SMC for this specific context.
Topics: Child; Humans; Infant, Newborn; Chemoprevention; Cross-Sectional Studies; Malaria; Seasons; South Sudan
PubMed: 38267985
DOI: 10.1186/s12936-024-04853-x -
JMIR Research Protocols Jan 2024Seasonal malaria chemoprevention (SMC) is recommended by the World Health Organization for the sub-Sahel region in sub-Saharan Africa for preventing malaria in children...
BACKGROUND
Seasonal malaria chemoprevention (SMC) is recommended by the World Health Organization for the sub-Sahel region in sub-Saharan Africa for preventing malaria in children 3 months old to younger than 5 years. Since 2016, the Malian National Malaria Control Program has deployed SMC countrywide during its high malaria transmission season at a rate of 4 monthly cycles annually. The standard SMC regimen includes sulfadoxine-pyrimethamine (SP) plus amodiaquine (AQ). Resistance against SP is suspected to be rising across West Africa; therefore, assessing the effectiveness of an alternative antimalarial drug for SMC is needed to provide a second-line regimen when it is ultimately needed. It is not well understood whether SMC effectively prevents malaria in children aged 5 years or older.
OBJECTIVE
The primary goal of the study is to compare 2 SMC regimens (SP-AQ and dihydroartemisinin-piperaquine [DHA-PQ]) in preventing uncomplicated Plasmodium falciparum malaria in children 3 months to 9 years old. Secondly, we will assess the possible use of DHA-PQ as an alternative SMC drug in areas where resistance to SP or AQ may increase following intensive use.
METHODS
The study design is a 3-arm cluster-randomized design comparing the SP-AQ and DHA-PQ arms in 2 age groups (younger than 5 years and 5-9 years) and a control group for children aged 5-9 years. Standard SMC (SP-AQ) for children younger than 5 years was provided to the control arm, while SMC with SP-AQ was delivered to children aged 3 months to 9 years (arm 2), and SMC with DHA-PQ will be implemented in study arm 3 for children up to 9 years of age. The study was performed in Mali's Koulikoro District, a rural area in southwest Mali with historically high malaria transmission rates. The study's primary outcome is P falciparum incidence for 2 SMC regimens in children up to 9 years of age. Should DHA-PQ provide an acceptable alternative to SP-AQ, a plausible second-line prevention option would be available in the event of SP resistance or drug supply shortages. A significant byproduct of this effort included bolstering district health information systems for rapid identification of severe malaria cases.
RESULTS
The study began on July 1, 2019. Through November 2022, a total of 4556 children 3 months old to younger than 5 years were enrolled. Data collection ended in spring 2023, and the findings are expected to be published later in early 2024.
CONCLUSIONS
Routine evaluation of antimalarial drugs is needed to establish appropriate SMC age targets. The study goals here may impact public health policy and provide alternative therapies in the event of drug shortages or resistance.
TRIAL REGISTRATION
ClinicalTrials.gov NCT04149106, https://clinicaltrials.gov/ct2/show/NCT04149106.
INTERNATIONAL REGISTERED REPORT IDENTIFIER (IRRID)
DERR1-10.2196/51660.
PubMed: 38252481
DOI: 10.2196/51660 -
Tropical Medicine and Infectious Disease Dec 2023The combinations of artemether-lumefantrine (AL) and artesunate-amodiaquine (ASAQ) are used as first-line treatments for uncomplicated malaria in the Ivory Coast....
Meta-Analysis of Data from Four Clinical Trials in the Ivory Coast Assessing the Efficacy of Two Artemisinin-Based Combination Therapies (Artesunate-Amodiaquine and Artemether-Lumefantrine) between 2009 and 2016.
The combinations of artemether-lumefantrine (AL) and artesunate-amodiaquine (ASAQ) are used as first-line treatments for uncomplicated malaria in the Ivory Coast. Different studies document the efficacy of two artemisinin-based combination therapies (ACTs) (AL and ASAQ) in the Ivory Coast. However, there is no meta-analysis examining the data set of these studies. The purpose of this work was to determine the prevalence of malaria treatment failure cases in randomized control trials with two artemisinin-based combination therapies (AL versus ASAQ) in the Ivory Coast between 2009 to 2016. This study is a meta-analysis of data from the results of four previous multicenter, open-label, randomized clinical trial studies evaluating the clinical and parasitological efficacy of artemether-lumefantrine and artesunate-amodiaquine conducted between 2009 and 2016 following World Health Organization (WHO) protocol at sentinel sites in the Ivory Coast. These drug efficacy data collected between 2009 and 2016 were analyzed. During these studies, to distinguish between recrudescence and new infection, molecular genotyping of genes encoding merozoite surface protein 1 and 2 was carried out using nested polymerase chain reaction (PCR). A total of 1575 patients enrolled in the four studies, including 768 in the AL arm and 762 in the ASAQ arm, which were fully followed either for 28 days or 42 days according to WHO protocol. The adequate clinical and parasitological response (ACPR) was higher than 95% in the two groups (intention to treat (ITT): AL = 96.59% and ASAQ = 96.81; Per Protocol (PP): AL = 99.48% and ASAQ = 99.61%) after PCR correction at day 28. Aggregate data analysis (2009-2016) showed that at day 28, the proportions of patients with recurrent infection was higher in the AL group (ITT: 3.79%, PP: 3.9%) than in the ASAQ group (ITT: 2.17%, PP: 2.23%). After PCR correction, most treatment failures were classified as new infections (AL group (ITT: 0.13%, PP: 0.13%); ASAQ group (ITT: 0.39%, PP: 0.39%). The recrudescent infections rate was high, at 0.39% compared to 0.13% for ASAQ and AL, respectively, for both ITT and PP, no significant difference. However, the Kaplan-Meier curve of cumulative treatment success showed a significant difference between the two groups after PCR from 2012-2013 ( = 0.032). Overall, ASAQ and AL have been shown to be effective drugs for the treatment of uncomplicated malaria in the study areas, 14 years after deployment of these drugs.
PubMed: 38251206
DOI: 10.3390/tropicalmed9010010 -
Toxicological Sciences : An Official... Mar 2024Idiosyncratic drug reactions are rare but serious adverse drug reactions unrelated to the known therapeutic properties of the drug and manifest in only a small...
Idiosyncratic drug reactions are rare but serious adverse drug reactions unrelated to the known therapeutic properties of the drug and manifest in only a small percentage of the treated population. Animal models play an important role in advancing mechanistic studies examining idiosyncratic drug reactions. However, to be useful, they must possess similarities to those seen clinically. Although mice currently represent the dominant mammalian genetic model, rats are advantageous in many areas of pharmacologic study where their physiology can be examined in greater detail and is more akin to that seen in humans. In the area of immunology, this includes autoimmune responses and susceptibility to diabetes, in which rats more accurately mimic disease states in humans compared with mice. For example, oral nevirapine treatment can induce an immune-mediated skin rash in humans and rats, but not in mice due to the absence of the sulfotransferase required to form reactive metabolites of nevirapine within the skin. Using CRISPR-mediated gene editing, we developed a modified line of transgenic rats in which a segment of IgG-like ectodomain containing the core PD-1 interaction motif containing the native ligand and therapeutic antibody domain in exon 2 was deleted. Removal of this region critical for mediating PD-1/PD-L1 interactions resulted in animals with an increased immune response resulting in liver injury when treated with amodiaquine.
Topics: Humans; Rats; Mice; Animals; Nevirapine; Programmed Cell Death 1 Receptor; CRISPR-Cas Systems; Models, Animal; Liver; Drug-Related Side Effects and Adverse Reactions; Mammals
PubMed: 38230816
DOI: 10.1093/toxsci/kfae003 -
Journal of Pharmaceutical Policy and... 2024To guarantee uninterrupted service delivery, quality-assured products must be affordable and continuously available across all sectors, including the private sector,...
BACKGROUND
To guarantee uninterrupted service delivery, quality-assured products must be affordable and continuously available across all sectors, including the private sector, which provides more than 60% of healthcare services in Nigeria. We investigated the private sector availability and affordability of under 5 malaria commodities to establish the level of access in this sector.
METHODS
We surveyed patent medicine and pharmacy stores across seven states in Nigeria and the Federal Capital Territory to establish the availability and affordability of selected malaria commodities for children under 5 years. Availability was measured as the percentage of visited outlets with the product of interest on the day of visit, while affordability was assessed by establishing if it cost more than a day's wage for the least-paid government worker to purchase a full course of malaria diagnostic test and/or medication.
RESULTS
Artemisinin-based antimalarials for uncomplicated and severe malaria were the most available commodities. SPAQ1 and SPAQ2 used for seasonal malaria chemoprevention campaign were surprisingly also available in some outlets. However, only about half (48.3% and 53.3%) of the surveyed outlets had stock of artemether/lumefantrine (AL1) and artesunate injection, respectively. The median price of surveyed products ranged from USD (United States Dollars) 0.38 to USD 2.17 per treatment/test. Except for amodiaquine tablet and artemether injection, which cost less, all other originator brands cost the same or more than the lowest-priced generic. Antimalarial products were affordable as their median prices were not more than a day's wage for the least-paid government worker. However, when the cost of testing and treatment with artemisinin-based combination therapies (ACTs) was assessed, testing and treatment with dihydroartemisinin/piperaquine were unaffordable as the they cost more than 1.5 times the daily wage of the least-paid government worker.
CONCLUSION
The overall private sector availability of under-five malaria commodities in surveyed locations was suboptimal. Also, testing and treatment with recommended ACTs were not affordable for all surveyed products. These findings suggest the need for interventions to improve access to affordable under-five malaria commodities.
PubMed: 38223355
DOI: 10.1080/20523211.2023.2294024 -
Gates Open Research 2023The World Health Organization (WHO) recommends seasonal malaria chemoprevention (SMC) with sulfadoxine-pyrimethamine and amodiaquine (SPAQ) for children aged 3 to 59...
A hybrid effectiveness-implementation study protocol to assess the effectiveness and chemoprevention efficacy of implementing seasonal malaria chemoprevention in five districts in Karamoja region, Uganda.
BACKGROUND
The World Health Organization (WHO) recommends seasonal malaria chemoprevention (SMC) with sulfadoxine-pyrimethamine and amodiaquine (SPAQ) for children aged 3 to 59 months, living in areas where malaria transmission is highly seasonal. However, due to widespread prevalence of resistance markers, SMC has not been implemented at scale in East and Southern Africa. An initial study in Uganda showed that SMC with SPAQ was feasible, acceptable, and protective against malaria in eligible children in Karamoja region. Nonetheless, exploration of alternative regimens is warranted since parasite resistance threats persist.
OBJECTIVE
The study aims to test the effectiveness of SMC with Dihydroartemisinin-piperaquine (DP) or SPAQ (DP-SMC & SPAQ-SMC), chemoprevention efficacy as well as the safety and tolerability of DP compared to that of SPAQ among 3-59 months old children in Karamoja region, an area of Uganda where malaria transmission is highly seasonal.
METHODS
A Type II hybrid effectiveness-implementation study design consisting of four components: 1) a cluster randomized controlled trial (cRCT) using passive surveillance to establish confirmed malaria cases in children using both SPAQ and DP; 2a) a prospective cohort study to determine the chemoprevention efficacy of SPAQ and DP (if SPAQ or DP clears sub-patent infection and provides 28 days of protection from new infection) and whether drug concentrations and/or resistance influence the ability to clear and prevent infection; 2b) a sub study examining pharmacokinetics of DP in children between 3 to <6 months; 3) a resistance markers study in children 3-59 months in the research districts plus the standard intervention districts to measure changes in resistance marker prevalence over time and finally; 4) a process evaluation.
DISCUSSION
This study evaluates the effects of SPAQ-SMC versus DP-SMC on clinical malaria in vulnerable children in the context of high parasite SP resistance, whilst informing on the best implementation strategies.
CONCLUSION
This study will inform malaria policy in high-burden countries, specifically on utility of SMC outside the sahel, and contribute to progress in malaria control.
Topics: Child, Preschool; Humans; Infant; Amodiaquine; Chemoprevention; Malaria; Prospective Studies; Randomized Controlled Trials as Topic; Seasons; Uganda
PubMed: 38196920
DOI: 10.12688/gatesopenres.14287.2