Amodiaquine combined with sulfadoxine/pyrimethamine versus artemisinin-based combinations for the treatment of uncomplicated falciparum malaria in Africa: a meta-analysis

Therapeutic efficacy of artemether-lumefantrine, artesunate-amodiaquine and dihydroartemisinin-piperaquine in the treatment of uncomplicated Plasmodium falciparum malaria in Sub-Saharan Africa: A systematic review and meta-analysis

Background

Sub-Saharan Africa has the highest burden of malaria in the world. Artemisinin-based combination therapies (ACTs) have been the cornerstone in the efforts to reduce the global burden of malaria. In the effort to facilitate early detection of resistance for artemisinin derivatives and partner drugs, WHO recommends monitoring of ACT’s efficacy in the malaria endemic countries. The present systematic meta-analysis study summarises the evidence of therapeutic efficacy of the commonly used artemisinin-based combinations for the treatment of uncomplicated P. falciparum malaria in Sub-Saharan Africa after more than a decade since the introduction of the drugs.

Methods

Fifty two studies carried out from 2010 to 2020 on the efficacy of artemether-lumefantrine or dihydro-artemisinin piperaquine or artesunate amodiaquine in patients with uncomplicated P. falciparum malaria in Sub-Saharan Africa were searched for using the Google Scholar, Cochrane Central Register of controlled trials (CENTRAL), PubMed, Medline, LILACS, and EMBASE online data bases. Data was extracted by two independent reviewers. Random analysis effect was performed in STATA 13. Heterogeneity was established using I² statistics.

Results

Based on per protocol analysis, unadjusted cure rates in malaria infected patients treated with artemether-lumefantrine (ALU), artesunate-amodiaquine (ASAQ) and dihydroartemisinin-piperaquine (DHP) were 89%, 94% and 91% respectively. However, the cure rates after PCR correction were 98% for ALU, 99% for ASAQ and 99% for DHP.

Conclusion

The present meta-analysis reports the overall high malaria treatment success for artemether-lumefantrine, artesunate-amodiaquine and dihydroartemisinin-piperaquine above the WHO threshold value in Sub-Saharan Africa.

Investigation of antimalarial drug pyrimethamine and its interaction with dsDNA by electrochemical and spectroscopic techniques

The electrochemical behavior of the antimalarial drug pyrimethamine (PMT) was examined at a screen printed carbon electrode (SPCE) in different aqueous supporting electrolytes using cyclic voltammetry (CV) and differential pulse voltammetry (DPV).

Effect of pyrimethamine treatment on male rat testicular cell population development

Pyrimethamine (PYR) is a drug used in the treatment of newborn with congenital Toxoplasmosis. Even when PYR is highly specific against parasites, it may provoke neutropenia in the patients apart from other affectations, conditions that usually justify its suspension. Moreover, medication against congenital toxoplasmosis coincides with the proliferation stage of Sertoli and germ cells. Although, there are several reports on the effect of this drug on mature testes, records of its effects on the testes of young individuals yet in the process of growth are still lacking. This work was aimed to study the effects of in vivo administration of PYR in the first 21 days of life of male rat pups by evaluating their testicular alterations and its long-term sequels on fertility. Through the determination of the levels of seminiferous epithelium maturity, apoptotic index and cell proliferation index at 7, 14, 35 and 90 days post-natal using immunocytochemical studies. The fertility of the treated rats was evaluated at 90 days. PYR-treated animals were found to undergo some kind of delays in seminiferous epithelium maturity, decreased cell proliferation index and an increase in apoptosis when compared with the control (p < 0.05). Epididymal sperm counts were also affected (p < 0.05). The application of folic acid (FA) in newborns treated with PYR decreased the severity of the problem (p < 0.05). This study provides strong evidence that the effect of PYR on testicular development is specific. It reinforces the importance of FA application in neonates treated with PYR to prevent the effect of the later on spermatogenesis.

Recent initiatives and strategies to developing new drugs for tropical parasitic diseases

BACKGROUND

Despite the toll of tropical parasitic diseases on human life in the developing world, present therapies still rely on drugs developed decades ago. In many cases, the clinical usefulness of these compounds is limited due to poor efficacy, toxicity and the constant attrition of drug resistance. The absence of a profit incentive regarding diseases afflicting the very poor has resulted in a lack of investment by the pharmaceutical industry in new chemotherapies.

OBJECTIVE

Given this background, this review addresses what alternative economic and scientific strategies have been implemented to procure novel drugs.

METHODS

The latest chemical, genetic and screening technologies to discover and develop drugs for tropical parasitic diseases are reviewed. In many cases these strategies are being implemented within the framework of public-private partnerships established to sustain dynamic drug development portfolios. Examples of public-private partnerships and their portfolios are discussed. Further, the contribution of dedicated academic screening centres to target discovery and preclinical prosecution of new small molecules is also highlighted. In every case, the latest scientific literature is cited, but also relevant press releases and website information to indicate the present vitality in the field.

CONCLUSION

The tools, institutions and consortia are now in place and evolving to deliver new pharmaceuticals. Short-term results have already been realised in the clinic, mainly through the provision of new formulations of existing drugs. Long-term and consistent investment will be required, however, to identify, develop and clinically validate new chemical entities.

Should malaria treatment be guided by a point of care rapid test? A threshold approach to malaria management in rural Burkina Faso

BACKGROUND

In Burkina Faso, rapid diagnostic tests for malaria have been made recently available. Previously, malaria was managed clinically. This study aims at assessing which is the best management option of a febrile patient in a hyperendemic setting. Three alternatives are: treating presumptively, testing, or refraining from both test and treatment. The test threshold is the tradeoff between refraining and testing, the test-treatment threshold is the tradeoff between testing and treating. Only if the disease probability lies between the two should the test be used.

METHODS AND FINDINGS

Data for this analysis was obtained from previous studies on malaria rapid tests, involving 5220 patients. The thresholds were calculated, based on disease risk, treatment risk and cost, test accuracy and cost. The thresholds were then matched against the disease probability. For a febrile child under 5 in the dry season, the pre-test probability of clinical malaria (3.2%), was just above the test/treatment threshold. In the rainy season, that probability was 63%, largely above the test/treatment threshold. For febrile children >5 years and adults in the dry season, the probability was 1.7%, below the test threshold, while in the rainy season it was higher (25.1%), and situated between the two thresholds (3% and 60.9%), only if costs were not considered. If they were, neither testing nor treating with artemisinin combination treatments (ACT) would be recommended.

CONCLUSIONS

A febrile child under 5 should be treated presumptively. In the dry season, the probability of clinical malaria in adults is so low, that neither testing nor treating with any regimen should be recommended. In the rainy season, if costs are considered, a febrile adult should not be tested, nor treated with ACT, but a possible alternative would be a presumptive treatment with amodiaquine plus sulfadoxine-pyrimethamine. If costs were not considered, testing would be recommended.

Efficacy and safety of dihydroartemisinin-piperaquine for treatment of uncomplicated Plasmodium falciparum malaria in endemic countries: meta-analysis of randomised controlled studies

The present review aimed to synthesise available evidence on the efficacy of dihydroartemisinin-piperaquine (DP) in treating uncomplicated Plasmodium falciparum malaria in people living in malaria-endemic countries by performing a meta-analysis of relevant studies. We searched relevant studies in electronic data bases up to December 2011. Published results from randomised controlled trials (RCTs) comparing efficacy of DP with other artemisinin-based combination therapies (ACTs), or non-ACTs, or placebo were selected. The primary endpoint was 28-day and 42-day treatment failure. We identified 26 RCTs. Many of the studies included in the present review were of high quality. Overall, DP, artesunate-mefloquine (MAS3) and artemether-lumefentrine (AL) were equally effective for reducing the risk of recurrent parasitaemia. The PCR confirmed efficacy of DP (99.5%) and MAS3 (97.7%) at day 28 exceeded 90%; both are efficacious. Comparable efficacy was also found for DP (95.6%) and AL (94.3%). The present review has documented that DP is comparable to other currently used ACTs such as MAS3 and AL in treating uncomplicated falciparum malaria. The better safety profile of DP and once-daily dosage improves adherence and its fixed co-formulation ensures that both drugs are taken together. Our conclusion is that DP has the potential to become a first-line antimalarial drug.

Alternative visual displays of metaanalysis of malaria treatment trials to facilitate translation of research into policy

Typically, metaanalyses show relative effects and heterogeneity, but not absolute effects-an essential element in policy decision. Data obtained through a systematic review of antimalarial treatment trials and virtual trials were used to generate a display that shows and quantifies absolute and relative effects as well as heterogeneity for comparative trials results. A plot of failure rates (with 95% confidence intervals) of the test drug on the y axis against the risk difference (RD) versus the comparator drug on the x axis is proposed; the area is divided into 4 quadrants by a vertical line (no RD) and a horizontal line (maximum tolerated failures, e.g., 10% for antimalarials). This allows identifying where a drug can be used (meeting efficacy requirements) and quantifying differences (versus another treatment option). The area of the polygon connecting the study points expresses heterogeneity. This graphic display is simple to prepare and interpret and combines in 1 graph both measures of absolute treatment effect and difference, as well as heterogeneity. It may complement current methods and provide useful information in policy decision making.

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:

Improving educational achievement and anaemia of school children: design of a cluster randomised trial of school-based malaria prevention and enhanced literacy instruction in Kenya

BACKGROUND

Improving the health of school-aged children can yield substantial benefits for cognitive development and educational achievement. However, there is limited experimental evidence on the benefits of school-based malaria prevention or how health interventions interact with other efforts to improve education quality. This study aims to evaluate the impact of school-based malaria prevention and enhanced literacy instruction on the health and educational achievement of school children in Kenya.

DESIGN

A factorial, cluster randomised trial is being implemented in 101 government primary schools on the coast of Kenya. The interventions are (i) intermittent screening and treatment of malaria in schools by public health workers and (ii) training workshops and support for teachers to promote explicit and systematic literacy instruction. Schools are randomised to one of four groups: receiving either (i) the malaria intervention alone; (ii) the literacy intervention alone; (iii) both interventions combined; or (iv) control group where neither intervention is implemented. Children from classes 1 and 5 are randomly selected and followed up for 24 months. The primary outcomes are educational achievement and anaemia, the hypothesised mediating variables through which education is affected. Secondary outcomes include malaria parasitaemia, school attendance and school performance. A nested process evaluation, using semi-structured interviews, focus group discussion and a stakeholder analysis will investigate the community acceptability, feasibility and cost-effectiveness of the interventions.

DISCUSSION

Across Africa, governments are committed to improve health and education of school-aged children, but seek clear policy and technical guidance as to the optimal approach to address malaria and improved literacy. This evaluation will be one of the first to simultaneously evaluate the impact of health and education interventions in the improvement of educational achievement. Reflection is made on the practical issues encountered in conducting research in schools in Africa.

TRIAL REGISTRATION

National Institutes of Health NCT00878007.

Efficacy of non-artemisinin- and artemisinin-based combination therapies for uncomplicated falciparum malaria in Cameroon

Background

The use of drug combinations, including non-artemisinin-based and artemisinin-based combination therapy (ACT), is a novel strategy that enhances therapeutic efficacy and delays the emergence of multidrug-resistant Plasmodium falciparum. Its use is strongly recommended in most sub-Saharan African countries, namely Cameroon, where resistance to chloroquine is widespread and antifolate resistance is emerging.

Methods

Studies were conducted in Cameroonian children with acute uncomplicated P. falciparum malaria according to the standard World Health Organization protocol at four sentinel sites between 2003 and 2007. A total of 1,401 children were enrolled, of whom 1,337 were assigned to randomized studies and 64 were included in a single non-randomized study. The proportions of adequate clinical and parasitological response (PCR-uncorrected on day 14 and PCR-corrected on day 28) were the primary endpoints to evaluate treatment efficacy on day 14 and day 28. The relative effectiveness of drug combinations was compared by a multi-treatment Bayesian random-effect meta-analysis.

Findings

The results based on the meta-analysis suggested that artesunate-amodiaquine (AS-AQ) is as effective as other drugs (artesunate-sulphadoxine-pyrimethamine [AS-SP], artesunate-chlorproguanil-dapsone [AS-CD], artesunate-mefloquine [AS-MQ], dihydroartemisinin-piperaquine [DH-PP], artemether-lumefantrine [AM-LM], amodiaquine, and amodiaquine-sulphadoxine-pyrimethamine [AQ-SP]). AM-LM appeared to be the most effective with no treatment failure due to recrudescence, closely followed by DH-PP.

Conclusion

Although AM-LM requires six doses, rather than three doses for other artemisinin-based combinations, it has potential advantages over other forms of ACT. Further studies are needed to evaluate the clinical efficacy and tolerance of these combinations in different epidemiological context.

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.

Existing antimalarial agents and malaria-treatment strategies

In the absence of prompt and efficacious treatment, malaria patients may progress within a few hours from having minor symptoms to severe disease and death. These last years have seen the development of several artemisinin-based combinations, new treatments for severe malaria patients, and new strategies such as intermittent preventive treatment or the home-based/near-home management of malaria. The health sector is now confronted with several treatment options and strategies, in contrast with the period when chloroquine monotherapy was the standard treatment. The major challenge remains the large-scale deployment, in the most efficient way, of the tools available today, including artemisinin-based combination treatments, within health systems that remain extremely weak in malaria endemic countries, particularly in sub-Saharan Africa. Health system research, exploring new potential approaches for the large-scale implementation of these interventions, should be promoted in parallel with that on new therapeutic agents to be used in the unlucky event of the emergence and spread of artemisinin resistance. The prospects of substantially decreasing the malaria burden are brighter today than 20 - 30 years ago, but the efforts and resources committed to this purpose should be maintained over a long period.

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.

Randomized trial of artesunate+amodiaquine, sulfadoxine-pyrimethamine+amodiaquine, chlorproguanal-dapsone and SP for malaria in pregnancy in Tanzania

Background

Malaria in pregnancy is serious, and drug resistance in Africa is spreading. Drugs have greater risks in pregnancy and determining the safety and efficacy of drugs in pregnancy is therefore a priority. This study set out to determine the efficacy and safety of several antimalarial drugs and combinations in pregnant women with uncomplicated malaria.

Methods

Pregnant women with non-severe, slide proven, falciparum malaria were randomised to one of 4 regimes: sulfadoxine-pyrimethamine [SP]; chlorproguanil-dapsone [CD]; SP+amodiaquine [SP+AQ] or amodiaquine+artesunate [AQ+AS]. Randomisation was on a 1∶2∶2∶2 ratio. Women were admitted for treatment, and followed at days 7, 14, 21, 28 after the start of treatment, at delivery and 6 weeks after delivery to determine adverse events, clinical and parasitological outcomes. Primary outcome was parasitological failure by day 28.

Results

1433 pregnant women were screened, of whom 272 met entry criteria and were randomised; 28 to SP, 81 to CD, 80 to SP+AQ and 83 to AQ+AS. Follow-up to day 28 post treatment was 251/272 (92%), and to 6 weeks following delivery 91%. By day 28 parasitological failure rates were 4/26 (15%, 95%CI 4–35) in the SP, 18/77 (23%, 95%CI 14–34) in the CD, 1/73 (1% 95%CI 7–0.001) in the SP+AQ and 7/75 (9% 95%CI 4–18) in the AQ+AS arms respectively. After correction by molecular markers for reinfection the parasitological failure rates at day 28 were 18% for CD, 1% for SP+AQ and 4.5% for AQ+AS. There were two maternal deaths during the trial. There was no apparent excess of stillbirths or adverse birth outcomes in any arm. Parasitological responses were strikingly better in pregnant women than in children treated with the same drugs at this site.

Conclusions

Failure rates with monotherapy were unacceptably high. The two combinations tested were efficacious and appeared safe. It should not be assumed that efficacy in pregnancy is the same as in children.

Trial Registration

ClinicalTrials.gov NCT00146731

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.

Artemisinin-based combinations versus amodiaquine plus sulphadoxine-pyrimethamine for the treatment of uncomplicated malaria in Faladje, Mali

BACKGROUND

Because of the emergence of chloroquine resistance in Mali, artemether-lumefantrine (AL) or artesunate-amodiaquine (AS+AQ) are recommended as first-line therapy for uncomplicated malaria, but have not been available in Mali until recently because of high costs.

METHODS

From July 2005 to January 2006, a randomized open-label trial of three oral antimalarial combinations, namely AS+AQ, artesunate plus sulphadoxine-pyrimethamine (AS+SP), and amodiaquine plus sulphadoxine-pyrimethamine (AQ+SP), was conducted in Faladje, Mali. Parasite genotyping by polymerase chain reaction (PCR) was used to distinguish new from recrudescent Plasmodium falciparum infections.

RESULTS

397 children 6 to 59 months of age with uncomplicated Plasmodium falciparum malaria were enrolled, and followed for 28 days to assess treatment efficacy. Baseline characteristics were similar in all three treatment groups. The uncorrected rates of adequate clinical and parasitologic response (ACPR) were 55.7%, 90.8%, and 97.7% in AS+AQ, AS+SP, and AQ+SP respectively (p < 0.001); after PCR correction ACPR rates were similar among treatment groups: 95.4%, 96.9%, and 99.2% respectively (p = 0.17). Mean haemoglobin concentration increased across all treatment groups from Day 0 (9.82 +/- 1.68 g/dL) to Day 28 (10.78 +/- 1.49 g/dL) (p < 0.001), with the greatest improvement occurring in children treated with AQ+SP. On Day 2, the prevalence of parasitaemia was significantly greater among children treated with AQ+SP (50.8%) than in children treated with AS+AQ (10.5%) or AS+SP (10.8%) (p < 0.001). No significant difference in gametocyte carriage was found between groups during the follow-up period.

CONCLUSION

The combination of AQ+SP provides a potentially low cost alternative for treatment of uncomplicated P. falciparum infection in Mali and appears to have the added value of longer protective effect against new infection.

Antimalarial drugs - what is in use and what is in the pipeline

Malaria continues to be a potentially fatal threat to almost half of the world's population. In light of this threat, the armory to fight this disease is rather limited. Resistance against the most common and affordable antimalarials is widespread. Only few new drugs are in clinical development, most of them belong to long used classes of antimalarial drugs. This review will concisely cover the drugs which are currently in use, and describe the drug candidates which are in clinical evaluation.

Sulfadoxine-pyrimethamine-based combinations for malaria: a randomised blinded trial to compare efficacy, safety and selection of resistance in Malawi

Background

In Malawi, there has been a return of Plasmodium falciparum sensitivity to chloroquine (CQ) since sulfadoxine-pyrimethamine (SP) replaced CQ as first line treatment for uncomplicated malaria. When used for prophylaxis, Amodiaquine (AQ) was associated with agranulocytosis but is considered safe for treatment and is increasingly being used in Africa. Here we compare the efficacy, safety and selection of resistance using SP or CQ+SP or artesunate (ART)+SP or AQ+SP for the treatment of uncomplicated falciparum malaria.

Methodology and Findings

455 children aged 1–5 years were recruited into a double-blinded randomised trial comparing SP to the three combination therapies. Using intention to treat analysis with missing outcomes treated as successes, and without adjustment to distinguish recrudescence from new infections, the day 28 adequate clinical and parasitological response (ACPR) rate for SP was 25%, inferior to each of the three combination therapies (p<0.001). AQ+SP had an ACPR rate of 97%, higher than CQ+SP (81%) and ART+SP (70%), p<0.001. Nineteen children developed a neutropenia of ≤0.5×10³ cells/µl by day 14, more commonly after AQ+SP (p = 0.03). The mutation pfcrt 76T, associated with CQ resistance, was detected in none of the pre-treatment or post-treatment parasites. The prevalence of the pfmdr1 86Y mutation was higher after treatment with AQ+SP than after SP, p = 0.002.

Conclusions

The combination AQ+SP was highly efficacious, despite the low efficacy of SP alone; however, we found evidence that AQ may exert selective pressure for resistance associated mutations many weeks after treatment. This study confirms the return of CQ sensitivity in Malawi and importantly, shows no evidence of the re-emergence of pfcrt 76T after treatment with CQ or AQ. Given the safety record of AQ when used as a prophylaxis, our observations of marked falls in neutrophil counts in the AQ+SP group requires further scrutiny.

Trial Registration

Controlled-Trials.com ISRCTN22075368

Pharmacodynamic interaction between 4-aminoquinolines and retinol in Plasmodium falciparum in vitro

The pharmacodynamic interaction between retinol and 4-aminoquinolines has been investigated in 29 fresh isolates of Plasmodium falciparum. Although the parasites were highly resistant against 4-aminoquinolines, significant synergism was observed between chloroquine and retinol as well as amodiaquine and retinol, the latter at physiological concentrations. Combination with retinol reduced the geometric mean concentrations effecting complete inhibition (GMCOC) by chloroquine from 14425 nM to 8943 nM in CHL-RET low, 7042 nM in CHL-RET medium, and 4920 nM in CHL-RET high. Synergism between amodiaquine and retinol was greater, with strong and highly significant reductions of the GMCOC, from 2520 nM for amodiaquine to 1092 nM for AMO-RET low, 800 nM for AMO-RET medium, and 745 nM for AMO-RET high. While it is obviously too late for making practical use of the activity enhancement for chloroquine, the situation is different for amodiaquine, where supplementation with retinol may extend the usefulness of the medicament.

Treating malaria in pregnancy in developing countries: priorities in clinical research and drug development

Reducing the burden of falciparum malaria in pregnancy is an urgent international public health priority but one that involves considerable challenges. The rapidly declining effectiveness of agents known to be safe in pregnancy, and the limited efficacy, safety and pharmacokinetic data available for many other antimalarial drugs, mean that current options for the treatment of both severe and uncomplicated falciparum malaria in pregnancy are limited. This report summarizes the literature on this subject and recommends drug combinations for evaluation in Phase II/III treatment trials in pregnancy.

Malaria Chemotherapeutics Part I: History of Antimalarial Drug Development, Currently Used Therapeutics, and Drugs in Clinical Development

Since ancient times, humankind has had to struggle against the persistent onslaught of pathogenic microorganisms. Nowadays, malaria is still the most important infectious disease worldwide. Considerable success in gaining control over malaria was achieved in the 1950s and 60s through landscaping measures, vector control with the insecticide DDT, and the widespread administration of chloroquine, the most important antimalarial agent ever. In the late 1960s, the final victory over malaria was believed to be within reach. However, the parasites could not be eradicated because they developed resistance against the most widely used and affordable drugs of that time. Today, cases of malaria infections are on the rise and have reached record numbers. This review gives a short description of the malaria disease, briefly addresses the history of antimalarial drug development, and focuses on drugs currently available for malaria therapy. The present knowledge regarding their mode of action and the mechanisms of resistance are explained, as are the attempts made by numerous research groups to overcome the resistance problem within classes of existing drugs and in some novel classes. Finally, this review covers all classes of antimalarials for which at least one drug candidate is in clinical development. Antimalarial agents that are solely in early development stages will be addressed in a separate review.

Randomized clinical trial of artemisinin versus non-artemisinin combination therapy for uncomplicated falciparum malaria in Madagascar

Background

Data concerning antimalarial combination treatment for uncomplicated malaria in Madagascar are largely lacking. Randomized clinical trial was designed to assess therapeutic efficacies of chloroquine (CQ), amodiaquine (AQ), sulphadoxine-pyrimethamine (SP), amodiaquine plus sulphadoxine-pyrimethamine combination (AQ+SP) and artesunate plus amodiaquine combination (AQ+AS).

Methods

287 children between 6 months and 15 years of age, with uncomplicated falciparum malaria, were enrolled in the study. Primary endpoints were the day-14 and day-28 risks of parasitological failure, either unadjusted or adjusted by genotyping.

Results

All treatment regimens, except for CQ treatment, gave clinical cure rates above 97% by day-14 and 92% by day-28 (PCR-corrected). AQ+SP was as effective as AQ+AS. The risk of new infection within the month after therapy was generally higher for AQ+AS than AQ+SP.

Conclusion

These findings show that the inexpensive and widely available combination AQ+SP may be valuable in for the treatment of uncomplicated malaria in Madagascar and could have an important role in this country, where much of the drugs administered go to patients who do not have malaria.

Treatment of childhood Plasmodium falciparum malaria: current challenges

Malaria continues to be a major cause of mortality and morbidity in tropical countries. Infection with Plasmodium falciparum may be asymptomatic, cause an uncomplicated febrile illness or give rise to severe disease complicated by coma, acidosis or severe anemia. Treatment of the febrile illness with two drugs--preferably in the form of an artemisinin-containing combination therapy--is now widely recommended, both for greater efficacy and in order to delay the evolution of drug resistance. The clinical picture of severe malaria differs according to the age and immune status of the individual; treatment requires a range of supportive measures, as well as an efficacious antimalarial drug. Insecticide-treated bednets and presumptive treatment programs are increasingly deployed in malaria control programs, while vaccines are showing promise.