Efficacy of sulphadoxine-pyrimethamine alone or combined with amodiaquine or chloroquine for the treatment of uncomplicated falciparum malaria in Ugandan children

Adherence to prescribed artemisinin-based combination therapy in Garissa and Bunyala districts, Kenya

Background

Following the development of resistance to anti-malarial mono-therapies, malaria endemic countries in Africa now use artemisinin-based combination therapy (ACT) as recommended first-line treatment for uncomplicated malaria. Patients' adherence to ACT is an important factor to ensure treatment efficacy, as well as to reduce the likelihood of parasite resistance to these drugs. This study reports adherence to a specific ACT, artemether-lumefantrine (AL), under conditions of routine clinical practice in Kenya.

Method

The study was undertaken in Garissa and Bunyala districts among outpatients of five government health facilities. Patients treated with AL were visited at home four days after having been prescribed the drug. Respondents (patients ≥ 15 years and caregivers of patients < 15 years) were interviewed using a standardized questionnaire, AL blister packs were physically inspected and the adherence status of patients was then recorded. Multivariate logistic regression modelling was used to determine predictors of adherence.

Results

Of the 918 patients included in the study, 588 (64.1%) were 'probably adherent', 291 (31.7%) were 'definitely non-adherent' and 39 (4.2%) were 'probably non-adherent'. Six factors were found to be significant predictors of adherence: patient knowledge of the ACT dosing regimen (odds ratio (OR) = 1.76; 95% CI = 1.32-2.35), patient age (OR = 1.65; 95% CI = 1.02-1.85), respondent age (OR = 1.37; 95% CI = 1.10-2.48), whether a respondent had seen AL before (OR = 1.46; 95% CI = 1.08-1.98), whether a patient had reported dislikes to AL (OR = 0.62 95% CI = 0.47-0.82) and whether a respondent had waited more than 24 hours to seek treatment (OR = 0.73; 95% CI = 0.54-0.99).

Conclusion

Overall, adherence to AL was found to be low in both Garissa and Bunyala districts, with patient knowledge of the AL dosing regimen found to be the strongest predictor of adherence. Interventions aimed at increasing community awareness of the AL dosing regimen, use of child friendly formulations and improving health workers' prescribing practices are likely to ensure higher adherence to AL and eventual treatment success.

Malaria treatment policy change and implementation: the case of Uganda

Malaria due to P. falciparum is the number one cause of morbidity and mortality in Uganda where it is highly endemic in 95% of the country. The use of efficacious and effective antimalarial medicines is one of the key strategies for malaria control. Until 2000, Chloroquine (CQ) was the first-line drug for treatment of uncomplicated malaria in Uganda. Due to progressive resistance to CQ and to a combination of CQ with Sulfadoxine-Pyrimethamine, Uganda in 2004 adopted the use of ACTs as first-line drug for treating uncomplicated malaria. A review of the drug policy change process and postimplementation reports highlight the importance of managing the policy change process, generating evidence for policy decisions and availability of adequate and predictable funding for effective policy roll-out. These and other lessons learnt can be used to guide countries that are considering anti-malarial drug change in future.

Efficacy of chloroquine and sulphadoxine-pyrimethamine either alone or in combination before introduction of ACT as first-line therapy in uncomplicated Plasmodium falciparum malaria in Jalpaiguri District, West Bengal, India

OBJECTIVE

In India, till recently, Chloroquine was used as first-line therapy in areas with Chloroquine sensitive Plasmodium falciparum malaria cases. The National Vector Borne Disease Control Programme (NVBDCP) has introduced artemisinin combination therapy (ACT) as first-line option to treat all P. falciparum cases in the country. This study was carried out to ascertain the efficacy of Chloroquine and Sulphadoxine-Pyrimethamine, either alone or in combination, before the launch of ACT by NVBDCP.

METHODS

A total of 300 P. falciparum malaria cases were enrolled randomly in three study arms, Chloroquine (CQ), Sulphadoxine-Pyrimethamine (SP) and Chloroquine plus Sulphadoxine-Pyrimethamine (CQ + SP). All patients were followed up for 28 days as per WHO (Assessment and Monitoring of Antimalarial Drug Efficacy for the Treatment of Uncomplicated Falciparum Malaria, Geneva, 2003) Protocol. Paired blood samples of treatment failure cases were collected and subjected to MSP 1, MSP 2 and GLURP genotyping for differentiation between re-infection and recrudescence. The data were analysed by Kaplan-Meier survival curve according to WHO standard procedures.

RESULTS

The overall failure rate including both early treatment failure (ETF) and late treatment failure (LTF) of CQ, SP and CQ + SP were 61%, 14% and 8%, respectively, in the study area. Of 60 recurrent malaria cases, genotyping was successful in 49 cases, revealing that most of the (46/49; 94%) cases of recurrent malaria were due to recrudescence.

CONCLUSION

In Jalpaiguri District the overall failure rate of CQ was 61% and of SP 14%, which was well above the WHO recommended cut-off threshold level (10%) for change of drug policy.

A study of toxicity and differential gene expression in murine liver following exposure to anti-malarial drugs: amodiaquine and sulphadoxine-pyrimethamine

Background

Amodiaquine (AQ) along with sulphadoxine-pyrimethamine (SP) offers effective and cheaper treatment against chloroquine-resistant falciparum malaria in many parts of sub-Saharan Africa. Considering the previous history of hepatitis, agranulocytosis and neutrocytopenia associated with AQ monotherapy, it becomes imperative to study the toxicity of co-administration of AQ and SP. In this study, toxicity and resulting global differential gene expression was analyzed following exposure to these drugs in experimental Swiss mice.

Methods

The conventional markers of toxicity in serum, oxidative stress parameters in tissue homogenates, histology of liver and alterations in global transcriptomic expression were evaluated to study the toxic effects of AQ and SP in isolation and in combination.

Results

The combination therapy of AQ and SP results in more pronounced hepatotoxicity as revealed by elevated level of serum ALT, AST with respect to their individual drug exposure regimen. Furthermore, alterations in the activity of major antioxidant enzymes (glutathione peroxidase, superoxide dismutase, catalase, glutathione reductase), indicating the development of oxidative stress, was more significant in AQ+SP combination therapy. cDNA microarray results too showed considerably more perturbed gene expression following combination therapy of AQ and SP as compared to their individual drug treatment. Moreover, a set of genes were identified whose expression pattern can be further investigated for identifying a good biomarker for potential anti-malarial hepatotoxicity.

Conclusion

These observations clearly indicate AQ+SP combination therapy is hepatotoxic in experimental Swiss mice. Microarray results provide a considerable number of potential biomarkers of anti-malarial drug toxicity. These findings hence will be useful for future drug toxicity studies, albeit implications of this study in clinical conditions need to be monitored with cautions.

Increasing malaria hospital admissions in Uganda between 1999 and 2009

BACKGROUND

Some areas of Africa are witnessing a malaria transition, in part due to escalated international donor support and intervention coverage. Areas where declining malaria rates have been observed are largely characterized by relatively low baseline transmission intensity and rapid scaling of interventions. Less well described are changing patterns of malaria burden in areas of high parasite transmission and slower increases in control and treatment access.

METHODS

Uganda is a country predominantly characterized by intense, perennial malaria transmission. Monthly pediatric admission data from five Ugandan hospitals and their catchments have been assembled retrospectively across 11 years from January 1999 to December 2009. Malaria admission rates adjusted for changes in population density within defined catchment areas were computed across three time periods that correspond to periods where intervention coverage data exist and different treatment and prevention policies were operational. Time series models were developed adjusting for variations in rainfall and hospital use to examine changes in malaria hospitalization over 132 months. The temporal changes in factors that might explain changes in disease incidence were qualitatively examined sequentially for each hospital setting and compared between hospital settings

RESULTS

In four out of five sites there was a significant increase in malaria admission rates. Results from time series models indicate a significant month-to-month increase in the mean malaria admission rates at four hospitals (trend P < 0.001). At all hospitals malaria admissions had increased from 1999 by 47% to 350%. Observed changes in intervention coverage within the catchments of each hospital showed a change in insecticide-treated net coverage from <1% in 2000 to 33% by 2009 but accompanied by increases in access to nationally recommended drugs at only two of the five hospital areas studied.

CONCLUSIONS

The declining malaria disease burden in some parts of Africa is not a universal phenomena across the continent. Despite moderate increases in the coverage of measures to reduce infection and disease without significant coincidental increasing access to effective medicines to treat disease may not lead to severe disease burden reductions in high transmission areas of Africa. More data is needed from a wider range of malaria settings to provide an honest tracking progress of the impact of scaled intervention coverage in Africa.

Molecular assessment of Plasmodium falciparum resistance to antimalarial drugs in Papua New Guinea using an extended ligase detection reaction fluorescent microsphere assay

Surveillance for Plasmodium falciparum drug resistance mutations is becoming an established tool for assessing antimalarial treatment effectiveness. We used an extended version of a high-throughput post-PCR multiplexed ligase detection reaction fluorescent microsphere assay (LDR-FMA) to detect single-nucleotide P. falciparum drug resistance polymorphisms in 402 isolates from children in Papua New Guinea (PNG) participating in an antimalarial treatment trial. There was a fixation of P. falciparum crt (pfcrt) K76T, pfdhfr C59R and S108N, and pfmdr1 mutations (92%, 93%, 95%, and 91%, respectively). Multiple mutations were frequent. Eighty-eight percent of isolates possessed a quintuple mutation (underlined), SVMNT, NRNI, KAA, and YYSND, in codons 72 to 76 for pfcrt; 51, 59, 108, and 164 for pfdhfr; 540, 581, and 613 for pfdhps; and 86, 184, 1034, 1042, and 1246 for pfmdr1, and four of these carried the K540E pfdhps allele. The pfmdr1 D1246Y mutation was associated with PCR-corrected day 42 in vivo treatment failure in children allocated piperaquine-dihydroartemisinin (P = 0.004). Although the pfmdr1 NFSDD haplotype was found in only four isolates, it has been associated with artemether-lumefantrine treatment failure in Africa. LDR-FMA allows the large-scale assessment of resistance-associated single-nucleotide polymorphisms (SNPs). Our findings reflect previous heavy 4-aminoquinoline/sulfadoxine-pyrimethamine use in PNG. Since artemether-lumefantrine and piperaquine-dihydroartemisinin will become first- and second-line treatments, respectively, the monitoring of pfmdr1 SNPs appears to be a high priority.

Active case detection, treatment of falciparum malaria with combined chloroquine and sulphadoxine/pyrimethamine and vivax malaria with chloroquine and molecular markers of anti-malarial resistance in the Republic of Vanuatu

Background

Chloroquine-resistant Plasmodium falciparum was first described in the Republic of Vanuatu in the early 1980s. In 1991, the Vanuatu Ministry of Health instituted new treatment guidelines for uncomplicated P. falciparum infection consisting of chloroquine/sulphadoxine-pyrimethamine combination therapy. Chloroquine remains the recommended treatment for Plasmodium vivax.

Methods

In 2005, cross-sectional blood surveys at 45 sites on Malo Island were conducted and 4,060 adults and children screened for malaria. Of those screened, 203 volunteer study subjects without malaria at the time of screening were followed for 13 weeks to observe peak seasonal incidence of infection. Another 54 subjects with malaria were followed over a 28-day period to determine efficacy of anti-malarial therapy; chloroquine alone for P. vivax and chloroquine/sulphadoxine-pyrimethamine for P. falciparum infections.

Results

The overall prevalence of parasitaemia by mass blood screening was 6%, equally divided between P. falciparum and P. vivax. Twenty percent and 23% of participants with patent P. vivax and P. falciparum parasitaemia, respectively, were febrile at the time of screening. In the incidence study cohort, after 2,303 person-weeks of follow-up, the incidence density of malaria was 1.3 cases per person-year with P. vivax predominating. Among individuals participating in the clinical trial, the 28-day chloroquine P. vivax cure rate was 100%. The 28-day chloroquine/sulphadoxine-pyrimethamine P. falciparum cure rate was 97%. The single treatment failure, confirmed by merozoite surface protein-2 genotyping, was classified as a day 28 late parasitological treatment failure. All P. falciparum isolates carried the Thr-76 pfcrt mutant allele and the double Asn-108 + Arg-59 dhfr mutant alleles. Dhps mutant alleles were not detected in the study sample.

Conclusion

Peak seasonal malaria prevalence on Malo Island reached hypoendemic levels during the study observation period. The only in vivo malaria drug efficacy trial thus far published from the Republic of Vanuatu showed chloroquine/sulphadoxine-pyrimethamine combination therapy for P. falciparum and chloroquine alone for P. vivax to be highly efficacious. Although the chloroquine-resistant pfcrt allele was present in all P. falciparum isolates, mutant alleles in the dhfr and dhps genes do not yet occur to the extent required to confer sulphadoxine-pyrimethamine resistance in this population.

[Assessing the application of Rwanda's national protocol for uncomplicated malaria treatment in healthcare institutions in Kigali City, Rwanda]

In November 2001, the National Health Ministry of Rwanda advocated a new therapeutic protocol replacing chloroquine by an amodiaquine+sulfadoxine-pyrimethamine combination for the treatment of uncomplicated malaria.

OBJECTIVES

This study had for aim to assess the application of this new protocol in Kigali healthcare institutions.

POPULATION AND METHODS

A knowledge, attitudes and practices study (KAP) was carried out between June and August 2003. A questionnaire was answered by 120 care providers working in 15 healthcare institutions selected randomly in health facilities treating uncomplicated malaria. Antimalarial treatments prescribed to 150 patients were also reviewed from consultation files and analyzed.

RESULTS

After analysis, 63.3% prescriptions were in line with the national protocol. Factors associated to the nonobservance of the national protocol were: the carer's ignorance of any recommended treatment, his doubt of efficacy of recommended drugs, and his fear of adverse effects.

CONCLUSIONS

The authors recommend informing the care providers about the national protocol. Findings also demonstrate the need to include care providers in any modifications of the national policy in terms of drug efficacy and potential adverse effects of the new strategy.

Effect of artesunate plus sulfadoxine-pyrimethamine on haematological recovery and anaemia, in Kenyan children with uncomplicated, Plasmodium falciparum malaria

Malaria-associated anaemia is a major public-health problem. Although the treatment of uncomplicated, Plasmodium falciparum malaria aims to clear the parasites, relieve the symptoms and permit haematological recovery, data on the impact of antimalarial treatment on haematological recovery are few. Haematological recovery and the prevalence of anaemia were therefore evaluated in 600 Kenyan children with uncomplicated malaria who were randomly assigned to one of three treatment groups. The children were given sulfadoxine-pyrimethamine (SP) on day 0, SP plus artesunate on day 0 (AS1), or SP on day 0 and artesunate on each of days 0-2 (AS3). Haemoglobin (Hb) concentrations were measured on days 0, 7, 14, 21 and 28, with haematological recovery defined as a day-28 Hb concentration of at least 11 g/dl. Only 96 (18%) of the 543 children who were anaemic (i.e. with <11.0 g Hb/dl) at enrolment achieved haematological recovery. The prevalence of anaemia fell from 91% on day 0 to 74% (252/340) by day 28 (P=0.065). Compared with SP alone, neither artesunate regimen resulted in higher Hb concentrations on day 28 (with means of 10.2, 9.9 and 10.2 g/dl for AS3, AS1 and SP, respectively; P=0.254), a higher frequency of haematological recovery (19%, 14% and 20% for AS3, AS1 and SP, respectively; P=0.301) or a greater reduction in the prevalence of anaemia (prevalences in the AS3, AS1 and SP arms falling from 90%, 89% and 93%, respectively, on day 0, to corresponding values of 71%, 82% and 69% on day 28; P=0.40). In fact, between days 0 and 7, the children in the AS3 arm showed a larger drop in mean Hb than the children in the other two treatment arms. In general, haematological recovery was most likely in older children who had mild anaemia at presentation and were parasitologically cured. Overall, the frequencies of haematological recovery were modest and not influenced by the artesunate treatments. Other factors contributing to anaemia need to be explored more fully.

Efficacy and tolerability of four antimalarial combinations in the treatment of uncomplicated Plasmodium falciparum malaria in Senegal

BACKGROUND

In view of the high level of chloroquine resistance in many countries, WHO has recommended the use of combination therapy with artemisinin derivatives in the treatment of uncomplicated malaria due to Plasmodium falciparum. Four antimalarial drug combinations, artesunate plus amodiaquine (Arsucam), artesunate plus mefloquine (Artequin), artemether plus lumefantrine (Coartem; four doses and six doses), and amodiaquine plus sulphadoxine-pyrimethamine, were studied in five health districts in Senegal.

METHODS

This is a descriptive, analytical, open, randomized study to evaluate the efficacy and tolerability of these four antimalarial combinations in the treatment of uncomplicated falciparum malaria using the 2002 WHO protocol.

RESULTS

All drug combinations demonstrated good efficacy. On day 28, all combinations resulted in an excellent clinical and parasitological response rate of 100% after correction for PCR results, except for the four-dose artemether-lumefantrine regimen (96.4%). Follow-up of approximately 10% of each treatment group on day 42 demonstrated an efficacy of 100%.The combinations were well tolerated clinically and biologically. No unexpected side-effect was observed and all side-effects disappeared at the end of treatment. No serious side-effect requiring premature termination of treatment was observed.

CONCLUSION

The four combinations are effective and well-tolerated.

Caregivers' perceived treatment failure in home-based management of fever among Ugandan children aged less than five years

Background

Home-based management of fever (HBMF) could improve prompt access to antimalarial medicines for African children. However, the perception of treatment failure by caregivers has not been assessed.

Methods

Caregiver's perceived treatment outcome in HBMF and in alternative sources of fever treatment was assessed in a rural Ugandan setting using nine hundred and seventy eight (978) caregivers of children between two and 59 months of age, who had reported fever within two weeks prior to the study.

Results

Lower caregivers' perceived treatment failure (15% and 23%) was observed in the formal health facilities and in HBMF, compared to private clinics (38%), drug shops (55%) or among those who used herbs (56%). Under HBMF, starting treatment within 24 hours of symptoms onset and taking treatment for the recommended three days duration was associated with a lower perceived treatment failure. Conversely, vomiting, convulsions and any illness in the month prior to the fever episode was associated with a higher perceived treatment failure.

Conclusion

In this medium malaria transmission setting, caregiver's perceived treatment outcome was better in HBMF compared to alternative informal sources of treatment.

Combined chloroquine, sulfadoxine/pyrimethamine and primaquine against Plasmodium falciparum in Central Java, Indonesia

BACKGROUND

Chloroquine (CQ) or sulfadoxine-pyrimethamine (SP) monotherapy for Plasmodium falciparum often leads to therapeutic failure in Indonesia. Combining CQ with other drugs, like SP, may provide an affordable, available and effective option where artemisinin-combined therapies (ACT) are not licensed or are unavailable.

METHODS

This study compared CQ (n = 29 subjects) versus CQ + SP (with or without primaquine; n = 88) for clinical and parasitological cure of uncomplicated falciparum malaria in the Menoreh Hills region of southern Central Java, Indonesia. Gametocyte clearance rates were measured with (n = 56 subjects) and without (n = 61) a single 45 mg dose of primaquine (PQ).

RESULTS

After 28 days, 58% of subjects receiving CQ had cleared parasitaemia and remained aparasitaemic, compared to 94% receiving CQ combined with SP (p < 0.001). Msp-2 genotyping permitted reinfection-adjusted cure rates for CQ and CQ combined with SP, 70% and 99%, respectively (p = 0.0006).

CONCLUSION

Primaquine exerted no apparent affect on cure of asexual stage parasitaemia, but clearly accelerated clearance of gametocytes. CQ combined with SP was safe and well-tolerated with superior efficacy over CQ for P. falciparum parasitaemia in this study.

Improved efficacy with amodiaquine instead of chloroquine in sulfadoxine/pyrimethamine combination treatment of falciparum malaria in Uganda: experience with fixed-dose formulation

Amodiaquine (AQ) is an affordable compound, chemically related to chloroquine (CQ) but often effective against CQ resistant Plasmodium falciparum. In Uganda, a pre-packed fixed-dose combination of CQ plus sulfadoxine/pyrimethamine (CQ+SP) called Homapak is used in the home based management of fever program (HBM). We performed a single blind randomized trial to determine the efficacy of AQ+SP in comparison with the fixed-dose CQ+SP (Homapak) in the treatment of uncomplicated falciparum malaria in Ugandan children aged 6 months to 5 years. The study was done in 2004 at Walkuba Health Center, a sub-urban area in Jinja district, Uganda. Primary outcome was the day 14 per protocol clinical and parasitological response according to the WHO. A total of 183 children were included (mean age 28 months) and 90% completed 28 days of follow up. The day 14 adequate clinical and parasitological response was 70.9% for CQ+SP and 97.4% for AQ+SP (p<0.001). In those given CQ+SP, treatment failure rates for the 6 months to 2 years age group were much higher (48.2%) than in the older children (18.2%, p=0.004). The day 28 PCR adjusted parasitological failure rates were also higher in the CQ+SP (31.3%) than in the AQ+SP group (13.1%) (p=0.003), with a higher gametocyte carriage among the CQ+SP group. We conclude that the efficacy of AQ+SP was significantly superior to the fixed-dose CQ+SP (Homapak), particularly among the youngest children. Thus, AQ could be used instead of CQ in combination with SP to improve the effectiveness against falciparum malaria in Uganda.

Chloroquine or amodiaquine combined with sulfadoxine-pyrimethamine for uncomplicated malaria: a systematic review

OBJECTIVE

To compare the efficacies against uncomplicated falciparum malaria of chloroquine (CQ), amodiaquine (AQ), sulfadoxine-pyrimethamine (SP) and combinations of these inexpensive drugs.

METHODS

We searched Medline, Embase, Cochrane CENTRAL Register of Controlled Trials, BIOSIS, Web of Science, African Index Medicus, DARE, Digital Dissertations and Current Controlled Trials for randomised or quasi-randomised controlled trials conducted between 1991 and June 2004 regardless of language and geography. We also contacted malaria experts, searched reference lists, and contacted individual authors for unreported study characteristics and additional data. Unpublished data were sought and included in the analyses.

RESULTS

Thirteen randomised trials (n = 4248) were identified and the summary relative risks of treatment failure at 28 days were calculated. There was marginal benefit in adding CQ to SP, compared with SP monotherapy (RR = 0.74, 95% CI 0.54-1.02). Combining AQ with SP was associated with a significantly lower risk of treatment failure than SP monotherapy (RR = 0.35, 95% CI 0.15-0.82) and AQ monotherapy (RR = 0.59, 95% CI 0.42-0.83). AQ plus SP was associated with a significantly lower risk of treatment failure than CQ plus SP (RR = 0.42, 95% CI 0.25-0.72). Serious adverse events were rare and did not increase with combination therapy.

CONCLUSION

Amodiaquine plus SP remains an efficacious, affordable and safe option for treating malaria in certain settings.

Rapid selection of dhfr mutant allele in Plasmodium falciparum isolates after the introduction of sulfadoxine/pyrimethamine in combination with 4-aminoquinolines in Papua New Guinea

To overcome the declining efficacy of the 4-aminoquinolines in Papua New Guinea, sulfadoxine/pyrimethamine (SP) was combined with the 4-aminoquinolines as the first line treatment for falciparum malaria since 2000. To assess how this change had affected SP resistant gene polymorphisms, we determined allele frequencies of dhfr and dhps in 113 Plasmodium falciparum isolates from Wewak, East Sepik of Papua New Guinea in 2002 and 2003. In dhfr, double mutant (ACNRNVI) was the predominant allele with a prevalence of 91%. We found a significant decrease of wild dhfr allele prevalence (7%) compared with that reported in the adjacent area of East Sepik called the Wosera region (57%), before the drug policy changed in 1990-1993. Between 2002 and 2003, the prevalence of this allele decreased from 15% to 3% (P=0.02). Two distinct microsatellite haplotypes flanking dhfr were found in isolates with dhfr double mutant, suggesting the selection of preexisting SP resistant parasites rather than a frequent occurrence of dhfr mutations. The dhfr/dhps quartet mutations (ACNRNVI in dhfr and SGEAA in dhps) were identified in six of the isolates (8%) from 2003. This genotype, which is associated with in vivo resistance to SP, has not been reported before in Papua New Guinea. These findings suggest that isolates resistant to SP were rapidly selected despite the use of the SP combination therapy, probably because of their preexisting high level of resistance to the 4-aminoquinoline partner drug.

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

BACKGROUND

Artemisinin-based combination treatments are strongly advocated, but supplies are limited. Sulfadoxine combined with amodiaquine is an alternative non-artemisinin combination.

OBJECTIVES

To compare sulfadoxine-pyrimethamine plus amodiaquine (SP plus AQ) with sulfadoxine-pyrimethamine plus artesunate (SP plus AS) for treating uncomplicated Plasmodium falciparum malaria.

SEARCH STRATEGY

We searched the Cochrane Infectious Diseases Group Specialized Register (October 2005), CENTRAL (The Cochrane Library 2005, Issue 4), MEDLINE (1966 to October 2005), EMBASE (1988 to October 2005), LILACS (October 2005), and reference lists. We also contacted researchers and organizations working in this field.

SELECTION CRITERIA

Randomized controlled trials comparing SP plus AS with SP plus AQ for treating uncomplicated P. falciparum malaria.

DATA COLLECTION AND ANALYSIS

Two authors independently applied the inclusion criteria, extracted data, and assessed methodological quality. The primary outcome measure was treatment failure (parasitological or clinical evidence of treatment failure between start of treatment and day 28). We calculated the relative risk (RR) with 95% confidence intervals (CI) for dichotomous data.

MAIN RESULTS

Four trials (775 participants) met the inclusion criteria. All were from areas of high and seasonal malaria transmission in Africa. Fewer participants using SP plus AQ failed treatment by day 28 (RR 0.59, 95% CI 0.42 to 0.83; 652 participants, 3 trials). Even excluding new infections, SP plus AQ performed better (RR 0.62, 95% CI 0.40 to 0.96; 649 participants, 3 trials). There was no statistically significant difference between the two treatments for treatment failure at day 14 (RR 1.14, 95% CI 0.47 to 2.78; 775 participants, 4 trials). SP plus AS was more effective at reducing gametocyte carriage at day seven (RR 2.31, 95% CI 1.36 to 3.92; 220 participants, 1 trial). One trial reported that one person - in the SP plus AQ group - developed severe malaria. Adverse events were poorly reported, but did not seem to differ in type and number between the two treatment combinations.

AUTHORS' CONCLUSIONS

SP plus AQ performed better at controlling treatment failure at day 28, but was not as good as SP plus AS at reducing gametocyte carriage at day seven. Careful consideration of local resistance patterns is required because resistance to sulfadoxine-pyrimethamine and amodiaquine are high in many areas. In order to delay development of resistance to artesunate, the combination with sulfadoxine-pyrimethamine should only be considered where both drugs are known to be effective. Data on adverse events are still lacking.

Mutations in Plasmodium falciparum dihydrofolate reductase and dihydropteroate synthase genes in Senegal

Senegal recently (2004) switched to sulfadoxine-pyrimethamine (SP) with amodiaquine as first line therapy for malaria in response to increasing chloroquine resistance. In anticipation of emerging resistance to SP as a result of this change in drug pressure, we set out to define the baseline prevalence of SP-associated mutations in the dhfr and dhps genes in Plasmodium falciparum using geographically diverse and longitudinally collected samples. A total of 153 blood samples were analysed from patients (5 years or older) with mild malaria after informed consent was obtained. Longitudinal samples were collected between 2000 and 2003 in Pikine, a suburb of Dakar. Geographically diverse site sampling was carried out in 2003. The mutation prevalence in DHFR codons 51, 59 and 108 is 65%, 61% and 78% in Pikine, 2003. The overall prevalence of the triple mutation that is associated with high-level pyrimethamine resistance is 61%. The mutation prevalence rate in DHPS codons 436 and 437 is 21% and 40%, respectively. There is significant geographic variation in genotypic resistance, as samples from Pikine in 2003 had higher mutation prevalence in the pfdhfr and pfdhps genes compared to samples from Tambacounda (P < 0.015). In summary, this study demonstrates a high background prevalence of SP resistance mutations already present in P. falciparum in Senegal.

Open randomized study of artesunate-amodiaquine vs. chloroquine-pyrimethamine-sulfadoxine for the treatment of uncomplicated Plasmodium falciparum malaria in Nigerian children

BACKGROUND

Artemisinin-based combination antimalarials are currently considered effective alternatives for the treatment of malaria in Africa, but there are few studies of such combinations in Nigerian children. We assessed the safety, treatment efficacy and effects on gametocyte carriage of the combination of artesunate plus amodiaquine and chloroquine plus pyrimethamine-sulfadoxine in children.

METHODS

We evaluated 153 children who were aged 12 years or younger who had uncomplicated Plasmodium falciparum malaria. Patients were randomly assigned a combination of artesunate (4 mg/kg of body weight daily for 3 days) plus amodiaquine (30 mg/kg over 3 days), or chloroquine (25 mg/kg over 3 days) plus pyrimethamine-sulfadoxine (25 mg/kg of the sulfadoxine component at presentation). The primary endpoints were the proportions of children with adequate clinical and parasitological response, late parasitological failure, late clinical failure and early treatment failure. The parasitological cure rates on days 14-28 were also used as the primary endpoints.

RESULTS

Both regimens were well tolerated; no child was withdrawn because of drug intolerance. All children treated with artesunate plus amodiaquine had adequate clinical and parasitological response (ACPR), while all but five children treated with chloroquine plus pyrimethamine-sulfadoxine had similar response. Fever clearance times were similar in the two treatment groups. However, the proportion of patients whose parasitaemia cleared by day 2 was significantly higher (100 vs. 50%, P = 0.00001) and parasite clearance was significantly faster (1.7 +/- 0.4 vs. 2.5 +/- 0.8 days, P = 0.0001) in children treated with artesunate plus amodiaquine. The cure rates on days 21 (100%vs. 94%, P = 0.03) and 28 (100%vs. 90%, P = 0.003) were also significantly higher in children treated with artesunate plus amodiaquine than in those treated with chloroquine plus pyrimethamine-sulfadoxine. Overall, a significantly higher proportion of children treated with chloroquine plus pyrimethamine-sulfadoxine carried gametocytes at least once during follow-up compared with those treated with artesunate plus amodiaquine [5 of 50 (10%) vs. 1 of 103 (0.97%), P = 0.01].

CONCLUSION

The combination of artesunate plus amodiaquine is therapeutically superior to a combination of chloroquine plus pyrimethamine-sulfadoxine, and significantly reduced gametocyte carriage following treatment.

Chloroquine or amodiaquine combined with sulfadoxine-pyrimethamine for treating uncomplicated malaria

BACKGROUND

Chloroquine (CQ), amodiaquine (AQ), and sulfadoxine-pyrimethamine (SP) are inexpensive drugs, but treatment failure is a problem. Combination therapy may reduce treatment failure. CQ or AQ plus SP are affordable options of combination treatment, but there is debate about their effectiveness.

OBJECTIVES

To assess the combination of CQ or AQ plus SP compared with SP alone for first-line treatment of uncomplicated falciparum malaria.

SEARCH STRATEGY

We searched the Cochrane Infectious Diseases Group Specialized Register (April 2005), CENTRAL (The Cochrane Library Issue 2, 2005), MEDLINE (1966 to April 2005), EMBASE (1974 to April 2005), LILACS (1982 to April 2005), Science Citation Index (1981 to April 2005), African Index Medicus (1993 to 1998), and reference lists. We also contacted researchers at relevant organizations and a pharmaceutical company.

SELECTION CRITERIA

Randomized controlled trials in adults or children with uncomplicated Plasmodium falciparum malaria were eligible for inclusion. The main outcomes of interest were total and clinical failure at day 28 follow up and serious adverse events.

DATA COLLECTION AND ANALYSIS

Two people independently applied the inclusion criteria. One author extracted data and another checked them independently. We used relative risk (RR) and 95% confidence intervals (CI).

MAIN RESULTS

Twelve trials (2107 participants) met the inclusion criteria. A meta-analysis of five AQ trials (461 participants) showed a statistically significant reduction in total failure at day 28 with the combination therapy (RR 0.64, 95% CI 0.46 to 0.91), and meta-analysis of three trials (384 participants) showed a significant reduction in clinical failure at day 28 (RR 0.23, 95% CI 0.11 to 0.49). The statistical significance in the total failure analysis was sensitive to losses to follow up. Data from two CQ trials showed no advantage for total failure with combination therapy at day 28. There was no evidence from the included trials of serious adverse events.

AUTHORS' CONCLUSIONS

The evidence base is not strong enough to support firm conclusions. The available evidence suggests that AQ plus SP can achieve less treatment failure than SP, but this might depend on existing levels of parasite resistance to the individual drugs.

Rapid increase in resistance of Plasmodium falciparum to chloroquine-Fansidar in Uganda and the potential of amodiaquine-Fansidar as a better alternative

Combinations of chloroquine (CQ) and sulfadoxine-pyrimethamine (SP) [CQSP] as the first line agents in Uganda have replaced CQ monotherapy. The idea of the combination is to delay the development of malaria resistance to either drug when used alone. We compared the clinical, parasitological and molecular findings of two studies with treatment arms of CQSP, amodiaquine (AQ) plus SP (AQSP) both done in 2003 with a study done 1 year earlier (2002) using SP alone. There was a notable decrease in adequate clinical response (ACR) by day 14 from 92.7% with SP to 80% with the combination CQSP, a year later. AQSP combination was found to have the best effect (94.3% ACR). There were no early treatment failures in the AQSP group. However, treatment failures were recorded at 20% on day 14 and 43% on day 28 for CQSP treatment and 5.7% by day 14 and 28.8% by day 28 in the AQSP group. The number of mutations that are associated with SP resistance increased from 2002 to 2003 at all loci monitored, from 83.8 to 100% at codon 108, 58.7 to 76% at codon 59 in the DHFR gene, and from 58.8 to 86% at codon 437 and 33 to 43% at codon 540 in the DHPS gene. We conclude that there has been a rapid development of resistance since the introduction of the new policy guidelines. AQSP was found to be a superior drug combination compared to CQSP and could be used as a low cost alternative at the moment.

Supervised versus unsupervised intake of six-dose artemether-lumefantrine for treatment of acute, uncomplicated Plasmodium falciparum malaria in Mbarara, Uganda: a randomised trial

BACKGROUND

The six-dose regimen of artemether-lumefantrine is effective and is among combination therapies prioritised to replace antimalarials that no longer work in Africa. However, its effectiveness has not been assessed in the field, and could be compromised by poor adherence, incorrect timing of doses, and insufficient intake of fatty foods with every dose. Our aim, therefore, was to assess the effectiveness of artemether-lumefantrine prescribed under routine outpatient conditions, compared with its efficacy when given under supervision to inpatients with acute uncomplicated falciparum malaria.

METHODS

We did a randomised trial to compare the efficacy, safety, and pharmacokinetics of artemether-lumefantrine when given in a supervised (all doses observed with fatty-food intake; n=313) or unsupervised (first dose supervised followed by outpatient treatment with nutritional advice; n=644) setting to patients of all ages (weight >10 kg) with acute, uncomplicated falciparum malaria in Mbarara, Uganda. Our primary endpoint was 28 day, PCR-adjusted, parasitological cure rate. Analysis was by intention to treat and evaluability analysis.

FINDINGS

38 patients were lost to follow-up and one withdrew consent. Day-28 cure rates were 97.7% (296 of 303) and 98.0% (603 of 615) in the supervised and unsupervised groups, respectively. We recorded 15 non-severe, drug-related adverse events, all of which resolved.

INTERPRETATION

Artemether-lumefantrine has a high cure rate irrespective of whether given under supervision with food or under conditions of routine clinic practice. If used as first-line treatment, artemether-lumefantrine could make a substantial contribution to malaria control in Africa, though cost is an issue.

Two mutations in dihydrofolate reductase combined with one in the dihydropteroate synthase gene predict sulphadoxine–pyrimethamine parasitological failure in Ugandan children with uncomplicated falciparum malaria

The point mutations in the Plasmodium falciparum dihydrofolate reductase (dhfr) and the dihydropteroate synthase (dhps) genes that are linked to sulphadoxine-pyrimethamine (SP) resistance in vitro have been well characterised. To determine whether a few of these mutations could predict SP treatment failure in vivo, two mutations (Asn-108 and Arg-59) in the dhfr gene and one (Glu-540) in the dhps gene were analysed according to the risk of SP parasitological failure (RI-RIII) at day 28 in pre-treatment isolates in 79 Ugandan children aged 6-59 (mean = 18.4, S.D. = 8.8) months with uncomplicated falciparum malaria. Neither the dhfr-108 (P = 0.3) nor the dhps-540 (P = 0.6) or dhfr-108 + dhps-540 (P = 0.04) mutations were significantly associated with SP parasitological failure. However, the dhfr-108 + dhfr-59 (P = 0.04), the dhfr-59 + dhps-540 (P = 0.04) and the dhfr-108 + dhfr-59 + dhps-540 (P = 0.02) mutations significantly increased the risk for SP parasitological failure. Our findings confirm an earlier report that the dhfr-59 and the dhps-540 mutations could be useful genetic markers for rapid screening of populations at high risk of SP resistance.