Sulfadoxine-pyrimethamine plus artesunate versus sulfadoxine-pyrimethamine plus amodiaquine for treating uncomplicated malaria

Efficacy and safety of artemisinin-based combination therapy for uncomplicated Plasmodium falciparum malaria in Sudan: a systematic review and meta-analysis

Background

Malaria is a major public health problem in endemic countries including Sudan, where about 75% of populations are at risk. Due to widespread of chloroquine-resistant strains of Plasmodium falciparum, artemisinin-based combination therapy (ACT) is currently treatment of choice for malaria in the vast majority of malaria-endemic countries. This systematic review and meta-analysis is performed to obtain an overall stronger evidence of the outcomes of ACT in the treatment of uncomplicated falciparum malaria from the existing literature in Sudan.

Methods

The preferred reporting items for systematic review and meta-analysis statement were used to select studies to be included in this review. A computerized systematic strategy was adopted to search articles from PubMed, Google Scholar and Science Direct databases. Unpublished materials were also included. Open Meta-Analyst software was used to perform the meta-analysis. Random effects model was used to combine the included studies and the heterogeneity of studies was assessed using Cochrane Q and I² (χ² = 73.05, df (19), P < 0.001 and I² = 73.99).

Results

Twenty studies fulfilled the inclusion criteria (ACT in the treatment of uncomplicated falciparum malaria) and were included in the final analysis with a total number of 4070 participants. Malaria treatment outcome was assessed using World Health Organization guidelines. Adequate clinical and parasitological response was used to assess treatment success at the 28th day. Treatment success of all combined studies was 98% [(95% CI 97.2–98.8%), P < 0.001]. Treatment success was higher in malaria patients treated with artemether + lumefantrine (AL) than patients treated with artesunate + sulfadoxine–pyrimethamine (AS + SP) (98.9% (95% CI 98.4–99.4%) vs 97.1% (95% CI 95.5–98.6%), P < 0.001). Eleven studies reported adverse drug reactions (ADRs) to ACT (184 participants out of 3957 (4.65%). The ADRs were mild and resolved spontaneously. There was no severe ADRs or deaths.

Conclusion

Based on this review, the overall malaria treatment success was high (98%). AL regimen showed higher efficacy compared to AS + SP. The overall regimens were associated with mild low rates ADRs.

Electronic supplementary material

The online version of this article (10.1186/s12936-018-2265-x) contains supplementary material, which is available to authorized users.

The effect of dosing strategies on the therapeutic efficacy of artesunate-amodiaquine for uncomplicated malaria: a meta-analysis of individual patient data

BACKGROUND

Artesunate-amodiaquine (AS-AQ) is one of the most widely used artemisinin-based combination therapies (ACTs) to treat uncomplicated Plasmodium falciparum malaria in Africa. We investigated the impact of different dosing strategies on the efficacy of this combination for the treatment of falciparum malaria.

METHODS

Individual patient data from AS-AQ clinical trials were pooled using the WorldWide Antimalarial Resistance Network (WWARN) standardised methodology. Risk factors for treatment failure were identified using a Cox regression model with shared frailty across study sites.

RESULTS

Forty-three studies representing 9,106 treatments from 1999-2012 were included in the analysis; 4,138 (45.4%) treatments were with a fixed dose combination with an AQ target dose of 30 mg/kg (FDC), 1,293 (14.2%) with a non-fixed dose combination with an AQ target dose of 25 mg/kg (loose NFDC-25), 2,418 (26.6%) with a non-fixed dose combination with an AQ target dose of 30 mg/kg (loose NFDC-30), and the remaining 1,257 (13.8%) with a co-blistered non-fixed dose combination with an AQ target dose of 30 mg/kg (co-blistered NFDC). The median dose of AQ administered was 32.1 mg/kg [IQR: 25.9-38.2], the highest dose being administered to patients treated with co-blistered NFDC (median = 35.3 mg/kg [IQR: 30.6-43.7]) and the lowest to those treated with loose NFDC-25 (median = 25.0 mg/kg [IQR: 22.7-25.0]). Patients treated with FDC received a median dose of 32.4 mg/kg [IQR: 27-39.0]. After adjusting for reinfections, the corrected antimalarial efficacy on day 28 after treatment was similar for co-blistered NFDC (97.9% [95% confidence interval (CI): 97.0-98.8%]) and FDC (98.1% [95% CI: 97.6%-98.5%]; P = 0.799), but significantly lower for the loose NFDC-25 (93.4% [95% CI: 91.9%-94.9%]), and loose NFDC-30 (95.0% [95% CI: 94.1%-95.9%]) (P < 0.001 for all comparisons). After controlling for age, AQ dose, baseline parasitemia and region; treatment with loose NFDC-25 was associated with a 3.5-fold greater risk of recrudescence by day 28 (adjusted hazard ratio, AHR = 3.51 [95% CI: 2.02-6.12], P < 0.001) compared to FDC, and treatment with loose NFDC-30 was associated with a higher risk of recrudescence at only three sites.

CONCLUSIONS

There was substantial variation in the total dose of amodiaquine administered in different AS-AQ combination regimens. Fixed dose AS-AQ combinations ensure optimal dosing and provide higher antimalarial treatment efficacy than the loose individual tablets in all age categories.

Efficacy of different primaquine-based antimalarial regimens against Plasmodium falciparum gametocytemia

This study compared the efficacy against Plasmodium falciparum gametocytes of four regimens: amodiaquine-sulfadoxine/pyrimethamine (AQ-SP) and mefloquine-artesunate (MQ-AS), with and without primaquine (PQ) administered with the second dose of the schizonticide (AQ-SP; AQ-SP-PQ; MQ-AS; MQ-AS-PQ). Efficacy was determined by thick smear on days 1, 4 and 8 after the beginning of treatment. A total of 82 patients (19-23/group) were recruited. After AQ-SP administration, gametocytemia steadily increased until day 8. With AQ-SP-PQ, a marked decline in gametocytemia was detected on days 4 and 8. MQ-AS treatment resulted in reduced gametocytemia on days 4 and 8, and with MQ-AS-PQ it was reduced even further. None of the treatments cleared gametocytemia by day 8. Currently, artemisinin-based combination therapies plus PQ are the recommended treatment option against falciparum malaria; however, further studies are required to optimize the use of PQ. Issues to be addressed include the optimal time of administration, treatment duration, optimal daily and total dose, and day of evaluation of the gametocytocidal effect. In falciparum malaria, the WHO recommends a maximum of 4days of treatment; consequently, an effective regimen must clear asexual parasites and symptoms within this time frame. The same criteria should be taken into account when evaluating the anti-gametocyte activity.

Primaquina, gametocitemia de Plasmodium falciparum y bloqueo de transmisión: ineficacia del actual régimen de dosificación

Antecedentes: Los esquizonticidas anti-Plasmodium falciparum reducen la gametocitemia, sin erradicarla; por ello, se adiciona primaquina (PQ). Esta se administra al terminar el esquizonticida: día 4; 0,75 mg/kg; dosis única (régimen estándar). Las artemisininas actúan sobre gametocitos inmaduros I-IV de P. falciparum; la PQ actúa sobre gametocitos maduros (estadio V). ¿Cuál es la eficacia antigametocitos de la combinación esquizonticida-PQ? Objetivo:Analizar la eficacia de PQ-régimen estándar contra gametocitos de P. falciparum, asociada al esquizonticida. Metodología: Revisión sistemática de los artículos hallados en Pubmed y Lilacs. Resultados y conclusiones: Ningún esquizonticida elimina totalmente los gametocitos en 6-7 días iniciales de tratamiento. La adición de PQ-régimen estándar tiene potente acción antigametocitos. Ninguna combinación esquizonticida-PQ tiene eficacia total en ese plazo. No conocemos cómo varía la eficacia antigametocitos de PQ dada los días 1 a 3, ni en dosis diferentes a la estándar, ni en múltiples dosis. [Carmona-Fonseca J, ,Arango EM. Primaquina,gametocitemia de Plasmodium falciparum y bloqueo de transmisión: ineficacia del actual régimen de dosificación. MedUNAB 2012;15:14-21].

Effects of amodiaquine and artesunate on sulphadoxine-pyrimethamine pharmacokinetic parameters in children under five in Mali

BACKGROUND

Sulphadoxine-pyrimethamine, in combination with artesunate or amodiaquine, is recommended for the treatment of uncomplicated malaria and is being evaluated for intermittent preventive treatment. Yet, limited data is available on pharmacokinetic interactions between these drugs.

METHODS

In a randomized controlled trial, children aged 6-59 months with uncomplicated falciparum malaria, received either one dose of sulphadoxine-pyrimethamine alone (SP), one dose of SP plus three daily doses of amodiaquine (SP+AQ) or one dose of SP plus 3 daily doses of artesunate (SP+AS). Exactly 100 μl of capillary blood was collected onto filter paper before drug administration at day 0 and at days 1, 3, 7, 14, 21 and 28 after drug administration for analysis of sulphadoxine and pyrimethamine pharmacokinetic parameters.

RESULTS

Fourty, 38 and 31 patients in the SP, SP+AQ and SP+AS arms, respectively were included in this study. The concentrations on day 7 (that are associated with therapeutic efficacy) were similar between the SP, SP+AQ and SP+AS treatment arms for sulphadoxine (median [IQR] 35.25 [27.38-41.70], 34.95 [28.60-40.85] and 33.40 [24.63-44.05] μg/mL) and for pyrimethamine (56.75 [46.40-92.95], 58.75 [43.60-98.60] and 59.60 [42.45-86.63] ng/mL). There were statistically significant differences between the pyrimethamine volumes of distribution (4.65 [3.93-6.40], 4.00 [3.03-5.43] and 5.60 [4.40-7.20] L/kg; p = 0.001) and thus elimination half-life (3.26 [2.74 -3.82], 2.78 [2.24-3.65] and 4.02 [3.05-4.85] days; p < 0.001). This study confirmed the lower SP concentrations previously reported for young children when compared with adult malaria patients.

CONCLUSION

Despite slight differences in pyrimethamine volumes of distribution and elimination half-life, these data show similar exposure to SP over the critical initial seven days of treatment and support the current use of SP in combination with either AQ or AS for uncomplicated falciparum malaria treatment in young Malian children.

Drug-Resistant Malaria: The Era of ACT

As drug-resistant falciparum malaria has continued to evolve and spread worldwide, artemisinin-based combination therapies (ACT) have become the centerpiece of global malaria control over the past decade. This review discusses how advances in antimalarial drug resistance monitoring and rational use of the array of ACTs now available can maximize the impact of this highly efficacious therapy, even as resistance to artemisinins is emerging in Southeast Asia.

New emerging drug-resistant malaria

Clinical question

What is the best treatment for artemisinin-resistant malaria?

Results

There is still no better treatment than the presently used artemisinin-based combination therapies. A new antimalarial drug for this problem needs to be found.

Implementation

Pitfalls to avoid when treating drug-resistant malaria:

Evidence for perinatal and child health care guidelines in crisis settings: can Cochrane help?

BACKGROUND

It is important that healthcare provided in crisis settings is based on the best available research evidence. We reviewed guidelines for child and perinatal health care in crisis situations to determine whether they were based on research evidence, whether Cochrane systematic reviews were available in the clinical areas addressed by these guidelines and whether summaries of these reviews were provided in Evidence Aid.

METHODS

Broad internet searches were undertaken to identify relevant guidelines. Guidelines were appraised using AGREE and the clinical areas that were relevant to perinatal or child health were extracted. We searched The Cochrane Database of Systematic Reviews to identify potentially relevant reviews. For each review we determined how many trials were included, and how many were conducted in resource-limited settings.

RESULTS

Six guidelines met selection criteria. None of the included guidelines were clearly based on research evidence. 198 Cochrane reviews were potentially relevant to the guidelines. These reviews predominantly addressed nutrient supplementation, breastfeeding, malaria, maternal hypertension, premature labour and prevention of HIV transmission. Most reviews included studies from developing settings. However for large portions of the guidelines, particularly health services delivery, there were no relevant reviews. Only 18 (9.1%) reviews have summaries in Evidence Aid.

CONCLUSIONS

We did not identify any evidence-based guidelines for perinatal and child health care in disaster settings. We found many Cochrane reviews that could contribute to the evidence-base supporting future guidelines. However there are important issues to be addressed in terms of the relevance of the available reviews and increasing the number of reviews addressing health care delivery.

Amodiaquine dosage and tolerability for intermittent preventive treatment to prevent malaria in children

Sulfadoxine-pyrimethamine with amodiaquine (SP-AQ) is a highly efficacious regimen for intermittent preventive treatment to prevent malaria in children (IPTc), but the amodiaquine component is not always well tolerated. We determined the association between amodiaquine dosage by body weight and mild adverse events (AEs) and investigated whether alternative age-based regimens could improve dosing accuracy and tolerability, using data from two trials of IPTc in Senegal, one in which AQ dose was determined by age and the other in which it was determined by weight category. Both dosage strategies resulted in some children receiving AQ doses above the recommended therapeutic range. The odds of vomiting increased with increasing amodiaquine dosage. In one study, incidence of fever also increased with increasing dosage. Anthropometric data from 1,956 children were used to predict the dosing accuracy of existing and optimal alternative regimens. Logistic regression models describing the probability of AEs by dosage were used to predict the potential reductions in mild AEs for each regimen. Simple amendments to current AQ dosing schedules based on the child's age could substantially increase dosing accuracy and thus improve the tolerability of IPTc using SP-amodiaquine in situations where weighing the child is impractical.

Artemisinin-based combination therapies: a vital tool in efforts to eliminate malaria

Plasmodium falciparum resistance to chloroquine and sulphadoxine-pyrimethamine has led to the recent adoption of artemisinin-based combination therapies (ACTs) as the first line of treatment against malaria. ACTs comprise semisynthetic artemisinin derivatives paired with distinct chemical classes of longer acting drugs. These artemisinins are exceptionally potent against the pathogenic asexual blood stages of Plasmodium parasites and also act on the transmissible sexual stages. These combinations increase the rates of clinical and parasitological cures and decrease the selection pressure for the emergence of antimalarial resistance. This Review article discusses our current knowledge about the mode of action of ACTs, their pharmacological properties and the proposed mechanisms of drug resistance.

Artemisinin-based combination therapy for treating uncomplicated malaria

BACKGROUND

The World Health Organization recommends uncomplicated P. falciparum malaria is treated using Artemisinin-based Combination Therapy (ACT). This review aims to assist the decision making of malaria control programmes by providing an overview of the relative benefits and harms of the available options.

OBJECTIVES

To compare the effects of ACTs with other available ACT and non-ACT combinations for treating uncomplicated P. falciparum malaria.

SEARCH STRATEGY

We searched the Cochrane Infectious Diseases Group Specialized Register; the Cochrane Central Register of Controlled Trials (CENTRAL); MEDLINE; EMBASE; LILACS, and the metaRegister of Controlled Trials (mRCT) to March 2009.

SELECTION CRITERIA

Randomized head to head trials of ACTs in uncomplicated P. falciparum malaria.This review is limited to: dihydroartemisinin-piperaquine; artesunate plus mefloquine; artemether-lumefantrine (six doses); artesunate plus amodiaquine; artesunate plus sulfadoxine-pyrimethamine and amodiaquine plus sulfadoxine-pyrimethamine.

DATA COLLECTION AND ANALYSIS

Two authors independently assessed trials for eligibility and risk of bias, and extracted data. We analysed primary outcomes in line with the WHO 'Protocol for assessing and monitoring antimalarial drug efficacy' and compared drugs using risk ratios (RR) and 95% confidence intervals (CI). Secondary outcomes were effects on P. vivax, gametocytes, haemoglobin, and adverse events.

MAIN RESULTS

Fifty studies met the inclusion criteria. All five ACTs achieved PCR adjusted failure rates of < 10%, in line with WHO recommendations, at most study sites.Dihydroartemisinin-piperaquine performed well compared to the ACTs in current use (PCR adjusted treatment failure versus artesunate plus mefloquine in Asia; RR 0.39, 95% CI 0.19 to 0.79; three trials, 1062 participants; versus artemether-lumefantrine in Africa; RR 0.39, 95% CI 0.24 to 0.64; three trials, 1136 participants).ACTs were superior to amodiaquine plus sulfadoxine-pyrimethamine in East Africa (PCR adjusted treatment failure versus artemether-lumefantrine; RR 0.12, 95% CI 0.06 to 0.24; two trials, 618 participants; versus AS+AQ; RR 0.44, 95% CI 0.22 to 0.89; three trials, 1515 participants).Dihydroartemisinin-piperaquine (RR 0.32, 95% CI 0.24 to 0.43; four trials, 1442 participants) and artesunate plus mefloquine (RR 0.30, 95% CI 0.21 to 0.41; four trials, 1003 participants) were more effective than artemether-lumefantrine at reducing the incidence of P.vivax over 42 days follow up.

AUTHORS' CONCLUSIONS

Dihydroartemisinin-piperaquine is another effective first-line treatment for P. falciparum malaria.The performance of the non-ACT (amodiaquine plus sulfadoxine-pyrimethamine) falls below WHO recommendations for first-line therapy in parts of Africa.In areas where primaquine is not being used for radical cure of P. vivax, ACTs with long half-lives may provide some benefit.

Extended high efficacy of the combination sulphadoxine-pyrimethamine with artesunate in children with uncomplicated falciparum malaria on the Benin coast, West Africa

BACKGROUND

A study carried out in 2003-2005 in Southern Benin showed a day-28 sulphadoxine-pyrimethamine (SP) monotherapy failure rate greater than 40%, while for SP combined with artesunate (SP-AS) the failure rate was 5.3%. Such a large difference could be explained by the relatively short 28-day follow-up period, with a substantial number of recurrent infections possibly occurring after day 28. This paper reports the treatment outcome observed in the same study cohort beyond the initial 28-day follow-up.

METHODS

After the 28-day follow-up, children treated with either chloroquine alone (CQ), SP or SP-AS, were visited at home twice a week until day 90 after treatment. A blood sample was collected if the child had fever (axillary temperature > or =37.5 degrees C). Total clinical failure for each treatment group was estimated by combining all the early treatment failures and late clinical failures that occurred over the whole follow-up period, i.e. from day 0 up to day 90. Pre-treatment randomly selected blood samples were genotyped for the dhfr gene (59) and the dhps gene (437 and 540) point mutations related to SP resistance.

RESULTS

The PCR-corrected clinical failure at day 90 was significantly lower in the SP-AS group (SP-AS: 2.7%, SP alone: 38.2%; CQ: 41.1%) (Log-Rank p < 0,001). The most prevalent haplotype was dhfr Arg-59 with the dhps Gly-437 mutant and the dhps 540 wild type (85.5%). The dhps 540 mutation could be found in only three (8.3%) samples.

CONCLUSION

Combining artesunate to SP dramatically increased the treatment efficacy, even when extending the follow-up to day 90 post-treatment, and despite the high percentage of failures following treatment with SP alone. Such a good performance may be explained by the low prevalence of the dhps 540 mutation, by the rapid parasite clearance with artesunate and by the level of acquired immunity.

Modelling the impact of artemisinin combination therapy and long-acting treatments on malaria transmission intensity

BACKGROUND

Artemisinin derivatives used in recently introduced combination therapies (ACTs) for Plasmodium falciparum malaria significantly lower patient infectiousness and have the potential to reduce population-level transmission of the parasite. With the increased interest in malaria elimination, understanding the impact on transmission of ACT and other antimalarial drugs with different pharmacodynamics becomes a key issue. This study estimates the reduction in transmission that may be achieved by introducing different types of treatment for symptomatic P. falciparum malaria in endemic areas.

METHODS AND FINDINGS

We developed a mathematical model to predict the potential impact on transmission outcomes of introducing ACT as first-line treatment for uncomplicated malaria in six areas of varying transmission intensity in Tanzania. We also estimated the impact that could be achieved by antimalarials with different efficacy, prophylactic time, and gametocytocidal effects. Rates of treatment, asymptomatic infection, and symptomatic infection in the six study areas were estimated using the model together with data from a cross-sectional survey of 5,667 individuals conducted prior to policy change from sulfadoxine-pyrimethamine to ACT. The effects of ACT and other drug types on gametocytaemia and infectiousness to mosquitoes were independently estimated from clinical trial data. Predicted percentage reductions in prevalence of infection and incidence of clinical episodes achieved by ACT were highest in the areas with low initial transmission. A 53% reduction in prevalence of infection was seen if 100% of current treatment was switched to ACT in the area where baseline slide-prevalence of parasitaemia was lowest (3.7%), compared to an 11% reduction in the highest-transmission setting (baseline slide prevalence = 57.1%). Estimated percentage reductions in incidence of clinical episodes were similar. The absolute size of the public health impact, however, was greater in the highest-transmission area, with 54 clinical episodes per 100 persons per year averted compared to five per 100 persons per year in the lowest-transmission area. High coverage was important. Reducing presumptive treatment through improved diagnosis substantially reduced the number of treatment courses required per clinical episode averted in the lower-transmission settings although there was some loss of overall impact on transmission. An efficacious antimalarial regimen with no specific gametocytocidal properties but a long prophylactic time was estimated to be more effective at reducing transmission than a short-acting ACT in the highest-transmission setting.

CONCLUSIONS

Our results suggest that ACTs have the potential for transmission reductions approaching those achieved by insecticide-treated nets in lower-transmission settings. ACT partner drugs and nonartemisinin regimens with longer prophylactic times could result in a larger impact in higher-transmission settings, although their long term benefit must be evaluated in relation to the risk of development of parasite resistance.

Effects of Plasmodium falciparum parasite population size and patient age on early and late parasitological outcomes of antimalarial treatment in children

The design and interpretation of trials assessing the chemotherapeutic effects of antimalarial drugs depend on our understanding of how different selection criteria affect treatment outcomes. In this study, we analyzed the effects of baseline parameters on the initial parasite elimination rate and the risk of subsequent recrudescence as a marker for incompletely eliminated asexual blood-stage parasites in pediatric patients with uncomplicated Plasmodium falciparum infection treated with amodiaquine in a high-transmission area. We found that (i) parasite population size and patient age independently determine early and late parasitological treatment outcome measurements; (ii) the rate of recrudescence is higher in patients 1 to 3 years of age than in patients aged <1 or >3 years; (iii) patients aged >5 years with parasite densities between 2,000 and 10,000/microl have a lower recrudescence rate (13%; 95% confidence interval [CI], 8% to 21%) than patients aged <5 years with parasite densities of >10,000/microl (40%; 95% CI, 30% to 50%); and (iv) the sensitivity of detecting recrudescences outside this high-risk group, i.e., in patients of >5 years of age or with parasite densities of <10,000/microl, is as low as 27% or 22%, respectively. In conclusion, these findings highlight the need to use adequate selection criteria and to report parasitological outcome results adjusted for the readily available determinants of chemotherapeutic failure, i.e., patient age and baseline parasitemia. The thresholds may vary by transmission intensity and drug regimen. A better understanding of the limitations of antimalarial regimens in high-risk subgroups of patients has important implications for setting policy recommendations.