Pyrimethamine 25mg / Sulfadoxine 500mg tablets

BackgroundResistance of Plasmodium falciparum to sulfadoxine-pyrimethamine threatens the antimalarial effectiveness of intermittent preventive treatment during pregnancy (IPTp) in sub-Saharan Africa. We aimed to assess the associations between markers of sulfadoxine-pyrimethamine resistance in P falciparum and the effectiveness of sulfadoxine-pyrimethamine IPTp for malaria-associated outcomes.MethodsFor this systematic review and meta-analysis, we searched databases (from Jan 1, 1990 to March 1, 2018) for clinical studies (aggregated data) or surveys (individual participant data) that reported data on low birthweight (primary outcome) and malaria by sulfadoxine-pyrimethamine IPTp dose, and for studies that reported on molecular markers of sulfadoxine-pyrimethamine resistance. Studies that involved only HIV-infected women or combined interventions were excluded. We did a random-effects meta-analysis (clinical studies) or multivariate log-binomial regression (surveys) to obtain summarised dose-response data (relative risk reduction [RRR]) and multivariate meta-regression to explore the modifying effects of sulfadoxine-pyrimethamine resistance (as indicated by Ala437Gly, Lys540Glu, and Ala581Gly substitutions in the dhps gene). This study is registered with PROSPERO, number 42016035540.FindingsOf 1097 records screened, 57 studies were included in the aggregated-data meta-analysis (including 59 457 births). The RRR for low birthweight declined with increasing prevalence of dhps Lys540Glu (ptrend=0·0060) but not Ala437Gly (ptrend=0·35). The RRR was 7% (95% CI 0 to 13) in areas of high resistance to sulfadoxine-pyrimethamine (Lys540Glu ≥90% in east and southern Africa; n=11), 21% (14 to 29) in moderate-resistance areas (Ala437Gly ≥90% [central and west Africa], or Lys540Glu ≥30% to <90% [east and southern Africa]; n=16), and 27% (21 to 33) in low-resistance areas (Ala437Gly <90% [central and west Africa], or Lys540Glu <30% [east and southern Africa]; n=30; ptrend=0·0054 [univariate], I2=69·5%). The overall RRR in all resistance strata was 21% (17 to 25). In the analysis of individual participant data from 13 surveys (42 394 births), sulfadoxine-pyrimethamine IPTp was associated with reduced prevalence of low birthweight in areas with a Lys540Glu prevalence of more than 90% and Ala581Gly prevalence of less than 10% (RRR 10% [7 to 12]), but not in those with an Ala581Gly prevalence of 10% or higher (pooled Ala581Gly prevalence 37% [range 29 to 46]; RRR 0·5% [–16 to 14]; 2326 births).InterpretationThe effectiveness of sulfadoxine-pyrimethamine IPTp is reduced in areas with high resistance to sulfadoxine-pyrimethamine among P falciparum parasites, but remains associated with reductions in low birthweight even in areas where dhps Lys540Glu prevalence exceeds 90% but where the sextuple-mutant parasite (harbouring the additional dhps Ala581Gly mutation) is uncommon. Therapeutic alternatives to sulfadoxine-pyrimethamine IPTp are needed in areas where the prevalence of the sextuple-mutant parasite exceeds 37%.FundingUS Centers for Disease Control and Prevention, the Malaria in Pregnancy Consortium (funded through a grant from the Bill & Melinda Gates Foundation to the Liverpool School of Tropical Medicine), Worldwide Antimalarial Resistance Network, European and Developing Countries Clinical Trials Partnership.

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BACKGROUND: Intermittent preventive treatment in pregnancy (IPTp) with dihydroartemisinin-piperaquine is more effective than IPTp with sulfadoxine-pyrimethamine at reducing malaria infection during pregnancy in areas with high-grade resistance to sulfadoxine-pyrimethamine by Plasmodium falciparum in east Africa. We aimed to assess whether IPTp with dihydroartemisinin-piperaquine, alone or combined with azithromycin, can reduce adverse pregnancy outcomes compared with IPTp with sulfadoxine-pyrimethamine. METHODS: We did an individually randomised, double-blind, three-arm, partly placebo-controlled trial in areas of high sulfadoxine-pyrimethamine resistance in Kenya, Malawi, and Tanzania. HIV-negative women with a viable singleton pregnancy were randomly assigned (1:1:1) by computer-generated block randomisation, stratified by site and gravidity, to receive monthly IPTp with sulfadoxine-pyrimethamine (500 mg of sulfadoxine and 25 mg of pyrimethamine for 1 day), monthly IPTp with dihydroartemisinin-piperaquine (dosed by weight; three to five tablets containing 40 mg of dihydroartemisinin and 320 mg of piperaquine once daily for 3 consecutive days) plus a single treatment course of placebo, or monthly IPTp with dihydroartemisinin-piperaquine plus a single treatment course of azithromycin (two tablets containing 500 mg once daily for 2 consecutive days). Outcome assessors in the delivery units were masked to treatment group. The composite primary endpoint was adverse pregnancy outcome, defined as fetal loss, adverse newborn baby outcomes (small for gestational age, low birthweight, or preterm), or neonatal death. The primary analysis was by modified intention to treat, consisting of all randomised participants with primary endpoint data. Women who received at least one dose of study drug were included in the safety analyses. This trial is registered with ClinicalTrials.gov, NCT03208179. FINDINGS: From March-29, 2018, to July 5, 2019, 4680 women (mean age 25·0 years [SD 6·0]) were enrolled and randomly assigned: 1561 (33%; mean age 24·9 years [SD 6·1]) to the sulfadoxine-pyrimethamine group, 1561 (33%; mean age 25·1 years [6·1]) to the dihydroartemisinin-piperaquine group, and 1558 (33%; mean age 24·9 years [6.0]) to the dihydroartemisinin-piperaquine plus azithromycin group. Compared with 335 (23·3%) of 1435 women in the sulfadoxine-pyrimethamine group, the primary composite endpoint of adverse pregnancy outcomes was reported more frequently in the dihydroartemisinin-piperaquine group (403 [27·9%] of 1442; risk ratio 1·20, 95% CI 1·06-1·36; p=0·0040) and in the dihydroartemisinin-piperaquine plus azithromycin group (396 [27·6%] of 1433; 1·16, 1·03-1·32; p=0·017). The incidence of serious adverse events was similar in mothers (sulfadoxine-pyrimethamine group 17·7 per 100 person-years, dihydroartemisinin-piperaquine group 14·8 per 100 person-years, and dihydroartemisinin-piperaquine plus azithromycin group 16·9 per 100 person-years) and infants (sulfadoxine-pyrimethamine group 49·2 per 100 person-years, dihydroartemisinin-piperaquine group 42·4 per 100 person-years, and dihydroartemisinin-piperaquine plus azithromycin group 47·8 per 100 person-years) across treatment groups. 12 (0·2%) of 6685 sulfadoxine-pyrimethamine, 19 (0·3%) of 7014 dihydroartemisinin-piperaquine, and 23 (0·3%) of 6849 dihydroartemisinin-piperaquine plus azithromycin treatment courses were vomited within 30 min. INTERPRETATION: Monthly IPTp with dihydroartemisinin-piperaquine did not improve pregnancy outcomes, and the addition of a single course of azithromycin did not enhance the effect of monthly IPTp with dihydroartemisinin-piperaquine. Trials that combine sulfadoxine-pyrimethamine and dihydroartemisinin-piperaquine for IPTp should be considered. FUNDING: European & Developing Countries Clinical Trials Partnership 2, supported by the EU, and the UK Joint-Global-Health-Trials-Scheme of the Foreign, Commonwealth and Development Office, Medical Research Council, Department of Health and Social Care, Wellcome, and the Bill-&-Melinda-Gates-Foundation.

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BACKGROUND: To mitigate adverse consequences of malaria in pregnancy, the World Health Organization recommends intermittent preventive treatment of malaria in pregnancy (IPTp) with sulfadoxine-pyrimethamine. However, the effectiveness of IPTp with sulfadoxine-pyrimethamine has been threatened by widespread Plasmodium falciparum resistance, especially in East and Southern Africa. For IPTp, dihydroartemisinin-piperaquine has shown superior antimalarial effects compared to sulfadoxine-pyrimethamine, but sulfadoxine-pyrimethamine has been associated with improved birth outcomes compared to dihydroartemisinin-piperaquine. We hypothesized that a combination of both dihydroartemisinin-piperaquine and sulfadoxine-pyrimethamine would provide superior birth outcomes compared to either drug alone. METHODS AND FINDINGS: We conducted a double-blinded, randomized, controlled trial of 2,757 pregnant women in Uganda, where resistance of malaria parasites to sulfadoxine-pyrimethamine is widespread. Women were randomly assigned (1:1:1) to monthly IPTp with sulfadoxine-pyrimethamine, dihydroartemisinin-piperaquine, or dihydroartemisinin-piperaquine plus sulfadoxine-pyrimethamine. The primary outcome was the risk of a composite adverse birth outcome defined as any of the following: spontaneous abortion, stillbirth, low birthweight (LBW, < 2,500 g), preterm delivery (<37 weeks), small-for-gestational age, or neonatal death. Secondary outcomes included specific individual adverse birth outcomes, measures of malaria during pregnancy, and safety/tolerability. Combining dihydroartemisinin-piperaquine plus sulfadoxine-pyrimethamine did not reduce the risk of a composite adverse birth outcome compared to dihydroartemisinin-piperaquine (30.0% versus 30.9%, relative risk (RR) 0.97 [95% CI 0.84-1.12]; p = 0.70) or sulfadoxine-pyrimethamine (30.0% versus 26.4%, RR 1.14 [95% CI 0.98-1.33]; p = 0.10). The risk of a composite adverse birth outcome was higher with dihydroartemisinin-piperaquine compared to sulfadoxine-pyrimethamine (30.9% versus 26.4%, RR 1.17 [95% CI 1.01-1.36]; p = 0.04). Considering individual adverse birth outcomes, combining dihydroartemisinin-piperaquine plus sulfadoxine-pyrimethamine was associated with a higher risk of small-for-gestational age (23.4% versus 18.7%, RR 1.25 [95% CI 1.04-1.51]; p = 0.02) and low birthweight (8.6% versus 5.8%, RR 1.48 [95 CI 1.04-2.12]; p = 0.03) compared to sulfadoxine-pyrimethamine and a higher risk of preterm delivery (5.3% versus 3.1%, RR 1.73 [95% CI 1.07-2.79]; p = 0.03) compared to dihydroartemisinin-piperaquine. During pregnancy, compared to sulfadoxine-pyrimethamine, dihydroartemisinin-piperaquine was associated with a 94% reduction in the incidence of symptomatic malaria (0.46 versus 0.03 episodes per person-year, incidence rate ratio 0.06 [95% CI 0.03-0.12]; p < 0.001) and a 97% reduction in the risk of microscopic parasitemia (17.7% versus 0.6%, RR 0.03 [95% CI 0.02-0.05]; p < 0.001), but dihydroartemisinin-piperaquine plus sulfadoxine-pyrimethamine was not associated with improved malaria outcomes over dihydroartemisinin-piperaquine alone. There were no significant differences in the incidence of any grade 3-4 adverse events between the treatment arms. As this study was conducted in an area of high transmission intensity with widespread resistance to sulfadoxine-pyrimethamine, findings may not be generalizable to other settings. CONCLUSIONS: Despite the superior antimalarial activity of dihydroartemisinin-piperaquine, sulfadoxine-pyrimethamine alone was associated with improved birth outcomes. Combining dihydroartemisinin-piperaquine plus sulfadoxine-pyrimethamine for IPTp did not improve birth outcomes compared to either sulfadoxine-pyrimethamine or dihydroartemisinin-piperaquine alone. TRIAL REGISTRATION: ClinicalTrials.gov (NCT04336189; https://clinicaltrials.gov/study/NCT04336189).

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Summary Background Artemether-lumefantrine is widely used for uncomplicated Plasmodium falciparum malaria; sulfadoxine-pyrimethamine plus amodiaquine is used for seasonal malaria chemoprevention. We determined the efficacy of artemether-lumefantrine with and without primaquine and sulfadoxine-pyrimethamine plus amodiaquine with and without tafenoquine for reducing gametocyte carriage and transmission to mosquitoes. Methods In this phase 2, single-blind, randomised clinical trial conducted, asymptomatic individuals aged 10-50 years with P. falciparum gametocytaemia were randomised (1:1:1:1) to receive either artemether-lumefantrine, artemether-lumefantrine with a single dose of 0·25 mg/kg primaquine, sulfadoxine-pyrimethamine plus amodiaquine or sulfadoxine-pyrimethamine plus amodiaquine with a single dose of 1·66 mg/kg tafenoquine. All trial staff other than the pharmacist were blinded. The primary outcome was the median within person percent change in mosquito infection rate in infectious individuals from baseline to day 2 (artemether-lumefantrine groups) or 7 (sulfadoxine-pyrimethamine plus amodiaquine groups) post treatment, assessed by direct membrane feeding assay. This study is registered withClinicalTrials.gov, NCT05081089 . Findings Between 13 Oct and 16 Dec 2021, 1290 individuals were screened and 80 were enrolled and randomly assigned to one of the four treatment groups (20 per group). In individuals who were infectious before treatment, the median percentage reduction in mosquito infection rate 2 days after treatment was 100% (IQR 97·2-100; n=19, p=0·026) with artemether-lumefantrine and 100% (100-100; n=19, p=0·0001) with artemether-lumefantrine with primaquine. Only two individuals infected mosquitoes on day 2 after artemether-lumefantrine and none at day 5. In contrast, the median percentage reduction in mosquito infection rate 7 days after treatment was 63·60% (IQR 0·62 to 100, n=20, p=0·009) with sulfadoxine-pyrimethamine plus amodiaquine and 100% (100-100; n=19, p&lt;0·0001) with sulfadoxine-pyrimethamine plus amodiaquine with tafenoquine. Interpretation These data support the effectiveness of artemether-lumefantrine alone for preventing nearly all mosquito infections. In contrast, there was considerable post-treatment transmission after sulfadoxine-pyrimethamine plus amodiaquine where the addition of a transmission-blocking drug may be beneficial in maximizing its community impact. Funding Bill &amp; Melinda Gates Foundation Brief summary Sulfadoxine-pyrimethamine plus amodiaquine is commonly used for seasonal malaria chemoprevention. Artemether-lumefantrine is the most widely used treatment regimen for uncomplicated Plasmodium falciparum malaria, but studies to date have shown inconsistent activity of artemether-lumefantrine against P. falciparum gametocytes. This study shows considerable post-treatment transmission after sulfadoxine-pyrimethamine plus amodiaquine but near complete prevention of mosquito infection after artemether-lumefantrine, even without primaquine. The addition of 8-aminoquinolines reduced transmission with both combinations.

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Abstract Background Emergence of artemisinin partial resistance (ART-R) in Plasmodium falciparum is a growing threat to the efficacy of artemisinin combination therapies (ACT) and the efforts for malaria elimination. The emergence of Plasmodium falciparum Kelch13 (K13) R561H in Rwanda raised concern about the impact in neighboring Tanzania. In addition, regional concern over resistance affecting sulfadoxine-pyrimethamine (SP), which is used for chemoprevention strategies, is high. Methods To enhance longitudinal monitoring, the Molecular Surveillance of Malaria in Tanzania (MSMT) project was launched in 2020 with the goal of assessing and mapping antimalarial resistance. Community and clinic samples were assessed for resistance polymorphisms using a molecular inversion probe platform. Findings Genotyping of 6,278 samples collected countrywide in 2021 revealed a focus of K13 561H mutants in northwestern Tanzania (Kagera) with prevalence of 7.7% (50/649). A small number of 561H mutants (about 1%) were found as far as 800 km away in Tabora, Manyara, and Njombe. Genomic analysis suggests some of these parasites are highly related to isolates collected in Rwanda in 2015, supporting regional spread of 561H. However, a novel haplotype was also observed, likely indicating a second origin in the region. Other validated resistance polymorphisms (622I and 675V) were also identified. A focus of high sulfadoxine-pyrimethamine drug resistance was also identified in Kagera with a prevalence of dihydrofolate reductase 164L of 15% (80/526). Interpretation These findings demonstrate the K13 561H mutation is entrenched in the region and that multiple origins of ART-R, similar as to what was seen in Southeast Asia, have occurred. Mutations associated with high levels of SP resistance are increasing. These results raise concerns about the long-term efficacy of artemisinin and chemoprevention antimalarials in the region. Funding This study was funded by the Bill and Melinda Gates Foundation and the National Institutes of Health. Research in Context Evidence before this study We did a literature search via PubMed for research articles published from January 2014 to October 2023 using the search term “Africa” and “Artemisinin resistance” linked to “R561H” or “A675V” or “R622I”, returning 32 studies. The published literature shows the emergence and establishment of these three validated Plasmodium falciparum kelch13 (K13) mutations associated with artemisinin partial resistance (ART-R) in Africa. Large molecular studies of 675V in Uganda and 622I in Ethiopia have defined the regional spread of these mutations. However, limited data is available from recent studies about the spread and origins of the 561H mutation in the Great Lakes region of East Africa. In particular, detailed studies of the regions of Tanzania that border Rwanda have not been carried out since the mutation was detected in Rwanda. These data are needed for malaria control programs to define and implement strategies for controlling the spread of ART-R in Africa, a potential global public health disaster and the potential obstacle to the ongoing elimination strategies. Added value of this study This analysis reports the first large-scale analysis of antimalarial resistance in Tanzania, with a focus on the regions bordering Rwanda since the 561H mutation reached high frequency in the area. Using 6,278 P. falciparum positive samples sequenced using molecular inversion probes (MIPs), we show that the mutation has become frequent in the districts of Kagera bordering Rwanda. Importantly, we provide evidence for the separate emergence of a different extended haplotype around 561H in Tanzania. This is the first evidence that multiple independent emergences of the 561H ART-R have occurred in Africa, as was seen within the last two decades in Southeast Asia. Implications of all the available evidence These findings highlight that, similar to 622I and 675V in other parts of Africa, we can expect the 561H mutation to continue to spread in the region. In addition, it highlights that we need to be watchful for new origins of mutations beyond the spread of existing resistant parasite lineages. ART-R appears to now be well established in multiple areas in Eastern Africa. Intensive control in these regions to prevent spread and monitoring for partner drug resistance emergence in affected areas will be critical for preventing further reversal of malaria control efforts in the region and support progress to the elimination targets by 2023.

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Malaria is a great concern for global health and accounts for a large amount of morbidity and mortality, particularly in Africa, with sub-Saharan Africa carrying the greatest burden of the disease. Malaria control tools such as insecticide-treated bed nets, indoor residual spraying, and antimalarial drugs have been relatively successful in reducing the burden of malaria; however, sub-Saharan African countries encounter great challenges, the greatest being antimalarial drug resistance. Chloroquine (CQ) was the first-line drug in the 20th century until it was replaced by sulfadoxine-pyrimethamine (SP) as a consequence of resistance. The extensive use of these antimalarials intensified the spread of resistance throughout sub-Saharan Africa, thus resulting in a loss of efficacy for the treatment of malaria. SP was replaced by artemisinin-based combination therapy (ACT) after the emergence of resistance toward SP; however, the use of ACTs is now threatened by the emergence of resistant parasites. The decreased selective pressure on CQ and SP allowed for the reintroduction of sensitivity toward those antimalarials in regions of sub-Saharan Africa where they were not the primary drug for treatment. Therefore, the emergence and spread of antimalarial drug resistance should be tracked to prevent further spread of the resistant parasites, and the re-emergence of sensitivity should be monitored to detect the possible reappearance of sensitivity in sub-Saharan Africa.

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