Four Artemisinin-Based Treatments in African Pregnant Women with Malaria.

BACKGROUND: Information regarding the safety and efficacy of artemisinin combination treatments for malaria in pregnant women is limited, particularly among women who live in sub-Saharan Africa. METHODS: We conducted a multicenter, randomized, open-label trial of treatments for malaria in pregnant women in four African countries. A total of 3428 pregnant women in the second or third trimester who had falciparum malaria (at any parasite density and regardless of symptoms) were treated with artemether-lumefantrine, amodiaquine-artesunate, mefloquine-artesunate, or dihydroartemisinin-piperaquine. The primary end points were the polymerase-chain-reaction (PCR)-adjusted cure rates (i.e., cure of the original infection; new infections during follow-up were not considered to be treatment failures) at day 63 and safety outcomes. RESULTS: The PCR-adjusted cure rates in the per-protocol analysis were 94.8% in the artemether-lumefantrine group, 98.5% in the amodiaquine-artesunate group, 99.2% in the dihydroartemisinin-piperaquine group, and 96.8% in the mefloquine-artesunate group; the PCR-adjusted cure rates in the intention-to-treat analysis were 94.2%, 96.9%, 98.0%, and 95.5%, respectively. There was no significant difference among the amodiaquine-artesunate group, dihydroartemisinin-piperaquine group, and the mefloquine-artesunate group. The cure rate in the artemether-lumefantrine group was significantly lower than that in the other three groups, although the absolute difference was within the 5-percentage-point margin for equivalence. The unadjusted cure rates, used as a measure of the post-treatment prophylactic effect, were significantly lower in the artemether-lumefantrine group (52.5%) than in groups that received amodiaquine-artesunate (82.3%), dihydroartemisinin-piperaquine (86.9%), or mefloquine-artesunate (73.8%). No significant difference in the rate of serious adverse events and in birth outcomes was found among the treatment groups. Drug-related adverse events such as asthenia, poor appetite, dizziness, nausea, and vomiting occurred significantly more frequently in the mefloquine-artesunate group (50.6%) and the amodiaquine-artesunate group (48.5%) than in the dihydroartemisinin-piperaquine group (20.6%) and the artemether-lumefantrine group (11.5%) (P<0.001 for comparison among the four groups). CONCLUSIONS: Artemether-lumefantrine was associated with the fewest adverse effects and with acceptable cure rates but provided the shortest post-treatment prophylaxis, whereas dihydroartemisinin-piperaquine had the best efficacy and an acceptable safety profile. (Funded by the European and Developing Countries Clinical Trials Partnership and others; ClinicalTrials.gov number, NCT00852423.).

In vivo selection of Plasmodium falciparum Pfcrt and Pfmdr1 variants by artemether-lumefantrine and dihydroartemisinin-piperaquine in Burkina Faso.

Plasmodium falciparum Pfcrt-76 and Pfmdr1-86 gene polymorphisms were determined during a clinical trial in Burkina Faso comparing the efficacies of dihydroartemisinin-piperaquine (DHA-PPQ) and artemether-lumefantrine (AL). Significant selection of Pfcrt-K76 was observed after exposure to AL and DHA-PPQ, as well as selection of Pfmdr1-N86 after AL but not DHA-PPQ treatment, suggesting reverse selection on the Pfcrt gene by PPQ. These results support the rational use of DHA-PPQ in settings where chloroquine (CQ) resistance is high.

Ex vivo anti-malarial drug susceptibility of Plasmodium falciparum isolates from pregnant women in an area of highly seasonal transmission in Burkina Faso.

BACKGROUND: Ex vivo assays are usually carried out on parasite isolates collected from patients with uncomplicated Plasmodium falciparum malaria, from which pregnant women are usually excluded as they are often asymptomatic and with relatively low parasite densities. Nevertheless, P. falciparum parasites infecting pregnant women selectively sequester in the placenta and may have a different drug sensitivity profile compared to those infecting other patients. The drug sensitivity profile of P. falciparum isolates from infected pregnant women recruited in a treatment efficacy trial conducted in Burkina Faso was determined in an ex vivo study. METHODS: The study was conducted between October 2010 and December 2012. Plasmodium falciparum isolates were collected before treatment and at the time of any recurrent infection whose parasite density was at least 100/µl. A histidine-rich protein-2 assay was used to assess their susceptibility to a panel of seven anti-malarial drugs. The concentration of anti-malarial drug inhibiting 50% of the parasite maturation to schizonts (IC(50)) for each drug was determined with the IC Estimator version 1.2. RESULTS: The prevalence of resistant isolates was 23.5% for chloroquine, 9.2% for mefloquine, 8.0% for monodesethylamodiaquine, and 4.4% for quinine. Dihydroartemisinin, mefloquine, lumefantrine, and monodesethylamodiaquine had the lowest mean IC(50) ranging between 1.1 and 1.5 nM respectively. The geometric mean IC(50) of the tested drugs did not differ between chloroquine-sensitive and resistant parasites, with the exception of quinine, for which the IC(50) was higher for chloroquine-resistant isolates. The pairwise comparison between the IC(50) of the tested drugs showed a positive and significant correlation between dihydroartemisinin and both mefloquine and chloroquine, between chloroquine and lumefantrine and between monodesethylamodiaquine and mefloquine. CONCLUSION: These ex vivo results suggest that treatment with the currently available artemisinin-based combinations is efficacious for the treatment of malaria in pregnancy in Burkina Faso. TRIAL REGISTRATION: ClinicalTrials.gov ID: NCT00852423.

Challenges of non-commercial multicentre North-South collaborative clinical trials.

The last decade has witnessed a substantial increase of multi-centre, public health-oriented clinical trials in poor countries. However, non-commercial research groups have less staff and financial resources than traditional commercial sponsors, so the trial teams have to be creative to comply with Good Clinical Practices (GCP) requirements. According to the recent experience of a large multicentre trial on antimalarials, major challenges result from the complexity of multiple ethical review, the costs of in-depth monitoring at several sites, setting up an adequate Good Clinical Laboratory Practices (GCLP) framework, lack of insurers in host countries, and lack of adequate non-commercial data management software. Public research funding agencies need to consider these challenges in their funding policies. They also could support common spaces where North-South collaborative research groups may share critical information, such as on research insurance and open-source, GCP-compliant software. WHO should update its GCP guidelines, which date back to 1995, to incorporate the perspectives and needs of non-commercial clinical research.

Glucose-6-phosphate dehydrogenase deficiency, chlorproguanil-dapsone with artesunate and post-treatment haemolysis in African children treated for uncomplicated malaria.

BACKGROUND: Malaria is a leading cause of mortality, particularly in sub-Saharan African children. Prompt and efficacious treatment is important as patients may progress within a few hours to severe and possibly fatal disease. Chlorproguanil-dapsone-artesunate (CDA) was a promising artemisinin-based combination therapy (ACT), but its development was prematurely stopped because of safety concerns secondary to its associated risk of haemolytic anaemia in glucose-6-phosphate dehydrogenase (G6PD)-deficient individuals. The objective of the study was to assess whether CDA treatment and G6PD deficiency are risk factors for a post-treatment haemoglobin drop in African children<5 years of age with uncomplicated malaria. METHODS: This case-control study was performed in the context of a larger multicentre randomized clinical trial comparing safety and efficacy of four different ACT in children with uncomplicated malaria. Children, who after treatment experienced a haemoglobin drop≥2 g/dl (cases) within the first four days (days 0, 1, 2, and 3), were compared with those without an Hb drop (controls). Cases and controls were matched for study site, sex, age and baseline haemoglobin measurements. Data were analysed using a conditional logistic regression model. RESULTS: G6PD deficiency prevalence, homo- or hemizygous, was 8.5% (10/117) in cases and 6.8% (16/234) in controls (p=0.56). The risk of a Hb drop≥2 g/dl was not associated with either G6PD deficiency (adjusted odds ratio (AOR): 0.81; p=0.76) or CDA treatment (AOR: 1.28; p=0.37) alone. However, patients having both risk factors tended to have higher odds (AOR: 11.13; p=0.25) of experiencing a Hb drop≥2 g/dl within the first four days after treatment, however this finding was not statistically significant, mainly because G6PD deficient patients treated with CDA were very few. In non-G6PD deficient individuals, the proportion of cases was similar between treatment groups while in G6PD-deficient individuals, haemolytic anaemia occurred more frequently in children treated with CDA (56%) than in those treated with other ACT (29%), though the difference was not significant (p=0.49). CONCLUSION: The use of CDA for treating uncomplicated malaria may increase the risk of haemolytic anaemia in G6PD-deficient children.

Development, validation and evaluation of a rapid PCR-nucleic acid lateral flow immuno-assay for the detection of Plasmodium and the differentiation between Plasmodium falciparum and Plasmodium vivax.

BACKGROUND: Molecular tools are very sensitive and specific and could be an alternative for the diagnosis of malaria. The complexity and need for expensive equipment may hamper implementation and, therefore, simplifications to current protocols are warranted. METHODS: A PCR detecting the different Plasmodium species and differentiating between Plasmodium falciparum and Plasmodium vivax was developed and combined with a nucleic acid lateral flow immuno-assay (PCR-NALFIA) for amplicon detection. The assay was thoroughly evaluated for the analytical sensitivity and specificity in the laboratory, the robustness and reproducibility in a ring trial and accuracy and predictive value in a field trial. RESULTS: The analytical sensitivity and specificity were 0.978 (95% CI: 0.932-0.994) and 0.980 (95% CI: 0.924-0.997), respectively, and were slightly less sensitive for the detection of P. vivax than for P. falciparum. The reproducibility tested in three laboratories was very good (k = 0.83). This evaluation showed that the PCR machine used could influence the results. Accuracy was evaluated in Thailand and compared to expert microscopy and rapid diagnostic tests (RDTs). The overall and P. falciparum-specific sensitivity and specificity was good ranging from 0.86-1 and 0.95-0.98 respectively, compared to microscopy. Plasmodium vivax detection was better than the sensitivity of RDT, but slightly less than microscopy performed in this study. CONCLUSION: PCR-NALFIA is a sensitive, specific and robust assay able to identify Plasmodium species with good accuracy. Extensive testing including a ring trial can identify possible bottlenecks before implementation and is therefore essential to perform in additon to other evaluations.

Human Plasmodium knowlesi infections in young children in central Vietnam.

BACKGROUND: Considering increasing reports on human infections by Plasmodium knowlesi in Southeast Asian countries, blood samples collected during two large cross-sectional malariometric surveys carried out in a forested area of central Vietnam in 2004 and 2005 were screened for this parasite. METHODS: Blood samples collected at the 2004 survey and positive for Plasmodium malariae were randomly selected for PCR analysis detecting P. knowlesi. Blood samples collected in 2005 from the same individuals were screened again for P. knowlesi. Positive samples were confirmed by sequencing. Family members of positive cases who participated in both surveys were also screened. RESULTS: Ninety-five samples with P. malariae mono- or mixed infections identified by species-specific PCR were screened for P. knowlesi. Among the five (5.2%) positive samples by PCR, three were confirmed to be P. knowlesi infections by sequencing, two young children (<5 years old) and a young man, all asymptomatic at the time of the survey and for the next six months after the survey. One of the two children was still positive one year later. No infection was found among the family members. CONCLUSION: Plasmodium knowlesi infections in humans can be found in central Vietnam. A small child was positive for P. knowlesi in both surveys at one year interval, though it is unclear whether it was the same or a new infection.

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.

Varying efficacy of artesunate+amodiaquine and artesunate+sulphadoxine-pyrimethamine for the treatment of uncomplicated falciparum malaria in the Democratic Republic of Congo: a report of two in-vivo studies.

BACKGROUND: Very few data on anti-malarial efficacy are available from the Democratic Republic of Congo (DRC). DRC changed its anti-malarial treatment policy to amodiaquine (AQ) and artesunate (AS) in 2005. METHODS: The results of two in vivo efficacy studies, which tested AQ and sulphadoxine-pyrimethamine (SP) monotherapies and AS+SP and AS+AQ combinations in Boende (Equatorial province), and AS+SP, AS+AQ and SP in Kabalo (Katanga province), between 2003 and 2004 are presented. The methodology followed the WHO 2003 protocol for assessing the efficacy of anti-malarials in areas of high transmission. RESULTS: Out of 394 included patients in Boende, the failure rates on day 28 after PCR-genotyping adjustment of AS+SP and AS+AQ were estimated as 24.6% [95% CI: 16.6-35.5] and 15.1% [95% CI: 8.6-25.7], respectively. For the monotherapies, failure rates were 35.9% [95% CI: 27.0-46.7] for SP and 18.3% [95% CI: 11.6-28.1] for AQ. Out of 207 patients enrolled in Kabalo, the failure rate on day 28 after PCR-genotyping adjustment was 0 [1-sided 95% CI: 5.8] for AS+SP and AS+AQ [1-sided 95% CI: 6.2]. It was 19.6% [95% CI: 11.4-32.7] for SP monotherapy. CONCLUSION: The finding of varying efficacy of the same combinations at two sites in one country highlights one difficulty of implementing a uniform national treatment policy in a large country. The poor efficacy of AS+AQ in Boende should alert the national programme to foci of resistance and emphasizes the need for systems for the prospective monitoring of treatment efficacy at sentinel sites in the country.

Real-time PCR/MCA assay using fluorescence resonance energy transfer for the genotyping of resistance related DHPS-540 mutations in Plasmodium falciparum.

BACKGROUND: Sulphadoxine-pyrimethamine has been abandoned as first- or second-line treatment by most African malaria endemic countries in favour of artemisinin-based combination treatments, but the drug is still used as intermittent preventive treatment during pregnancy. However, resistance to sulphadoxine-pyrimethamine has been increasing in the past few years and, although the link between molecular markers and treatment failure has not been firmly established, at least for pregnant women, it is important to monitor such markers. METHODS: This paper reports a novel sensitive, semi-quantitative and specific real-time PCR and melting curve analysis (MCA) assay using fluorescence resonance energy transfer (FRET) for the detection of DHPS-540, an important predictor for SP resistance. FRET/MCA was evaluated using 78 clinical samples from malaria patients and compared to PCR-RFLP. RESULTS: Sixty-two samples were in perfect agreement between both assays. One sample showed a small wild type signal with FRET/MCA that indicates a polyclonal infection. Four samples were not able to generate enough material in both assays to distinguish mutant from wild-type infection, six samples gave no signal in PCR-RFLP and five samples gave no amplification in FRET/MCA. CONCLUSION: FRET/MCA is an effective tool for the identification of SNPs in drug studies and epidemiological surveys on resistance markers in general and DHPS-540 mutation in particular.

Sulfadoxine-pyrimethamine efficacy and selection of Plasmodium falciparum DHFR mutations in Burkina Faso before its introduction as intermittent preventive treatment for pregnant women.

Sulfadoxine-pyrimethamine efficacy was determined with a 28-day follow-up in 97 children between 6 months and 15 years of age. The polymerase chain reaction (PCR)-corrected treatment failure was 8.2% and the uncorrected was 21.6%. The presence of the dihydrofolate reductase (DHFR) and dihydropteroate synthetase (DHPS) mutations linked to sulfadoxine-pyrimethamine resistance before and after treatment was determined by PCR-restriction fragment length polymorphism (RFLP) and by a fluorogenic PCR assay. Before treatment, the prevalence of the triple DHFR mutations was higher among the patients having had a recurrent parasitemia (either recrudescence or new infection; 28.6% versus 9.3%), although the difference was not significant (P = 0.1). The double mutation Ala-436/Gly-437 was observed in 67% of samples, whereas no Glu-540 mutation was found. After treatment, the triple DHFR mutation was found in 76.2% of patients with recurrent parasitemia, recrudescence, and new infection alike. Such high prevalence of mutant parasites indicates that sulfadoxine-pyrimethamine should not be used as monotherapy.

Adding artesunate to sulphadoxine-pyrimethamine greatly improves the treatment efficacy in children with uncomplicated falciparum malaria on the coast of Benin, West Africa.

BACKGROUND: Benin has recently shifted its national antimalarial drug policy from monotherapies to combinations containing artemisinin derivatives. When this decision was taken, the available information on alternatives to chloroquine and sulphadoxine-pyrimethamine, the first- and second-line treatment, was sparse. METHODS: In 2003 - 2005, before the drug policy change, a randomized, open-label, clinical trial was carried out on the efficacy of chloroquine, and sulphadoxine-pyrimethamine alone or combined with artesunate, with the aim of providing policy makers with the information needed to formulate a new antimalarial drug policy. Children between six and 59 months of age, with uncomplicated malaria and living in the lagoon costal area in southern Benin, were randomly allocated to one of the three study arms and followed up for 28 days. RESULTS: Treatment failure (PCR corrected) was significantly lower in the artesunate + sulphadoxine-pyrimethamine group (4/77, 5.3%) than in chloroquine group(51/71, 71.8%) or the sulphadoxine-pyrimethamine alone group (30/70, 44.1%) (p < 0.001). Despite high sulphadoxine-pyrimethamine failure, its combination with artesunate greatly improved treatment efficacy. CONCLUSION: In Benin, artesunate + sulphadoxine-pyrimethamine is efficacious and could be used when the recommended artemisinin-based combinations (artemether-lumefantrine and amodiaquine-artesunate) are not available. However, because sulphadoxine-pyrimethamine is also used in pregnant women as intermittent preventive treatment, its combination with artesunate should not be widely employed in malaria patients as this may compromise the efficacy of intermittent preventive treatment.

A randomised trial to assess the safety and efficacy of artemether-lumefantrine (Coartem) for the treatment of uncomplicated Plasmodium falciparum malaria in Rwanda.

Coartem is a fixed-dose combination of artemether-lumefantrine that, given in six doses, provides effective treatment for children with uncomplicated Plasmodium falciparum infection in areas with highly endemic and multidrug-resistant malaria. In Rwanda since 2001, amodiaquine+sulfadoxine-pyrimethamine (AQ+SP) has been the first-line treatment, but resistance to this combination has rapidly emerged and spread. Coartem was considered as a possible alternative, and a randomised, open-label, clinical trial to test its safety, tolerability and efficacy was carried out in 2004-2005. Five hundred children aged 12-59 months with uncomplicated P. falciparum malaria were randomly allocated to AQ+SP or Coartem. Patients were followed up until day 28 after treatment. Adverse events and clinical and parasitological outcomes were recorded. Adequate clinical and parasitological response (ACPR) was significantly higher in children treated with Coartem than in those treated with AQ+SP: the PCR-adjusted 28-day ACPR was 96.68% for Coartem and 79.35% for AQ+SP. Both treatments rapidly cleared parasitaemia and fever, although parasite clearance was significantly faster in children treated with Coartem. Mean packed cell volume increased in all patients, with no significant differences between treatments. Coartem proved to be more efficacious than AQ+SP, with a good safety and tolerability profile.

Malaria transmission intensity and the rate of spread of chloroquine resistant Plasmodium falciparum: Why have theoretical models generated conflicting results?

The rate at which falciparum resistant malaria spreads in different transmission settings is still a controversial subject. We have assessed the spread of mutant Plasmodium falciparum parasites in six Ugandan populations with varying prevalence of chloroquine resistance (CQR), malaria transmission intensity, multiplicity of parasite clones and prevalence of CQ use. For each population, we have determined the wild and mutant allele frequency at codons 76 and 86 of the pfcrt and pfmdr1 genes, respectively. The highest frequency (median = 16.3%, range: 0.0-70.4%) of infections with two pure mutants (no wild genotype in either gene), adjusted for clone multiplicity, was observed at the extremes of malaria transmission intensity. The wild/mutant (W/M) allele ratio (an index for tracking the progression of CQR) was less than one in all sites (median = 0.51, range: 0.09-0.98) for the pfcrt-76 gene, while it was greater than one in two of six sites (median = 0.75, range: 0.4-1.6) for the pfmdr1-86 gene, suggesting that the pfcrt-76 mutants were the predominant parasites at all sites. Furthermore, the pfmdr1-86 W/M allele ratio was consistently higher than that of the pfcrt-76. The spread of mutations linked to CQR in P. falciparum commences with the pfcrt-76 gene mutations, followed later by the pfmdr1-86 gene mutations that modulate higher CQR. Such spread occurs faster at the extremes of the transmission spectrum and could explain why mathematical models have previously generated conflicting results with respect to malaria transmission intensity and spread of CQR.

Short report: molecular markers associated with Plasmodium falciparum resistance to sulfadoxine-pyrimethamine in the Democratic Republic of Congo.

Sulfadoxine-pyrimethamine (SP) is the first line antimalarial treatment in the Democratic Republic of Congo. Using polymerase chain reaction, we assessed the prevalence of mutations in the dihydrofolate reductase (dhfr) (codons 108, 51, 59) and dihydropteroate synthase (dhps) (codons 437, 540) genes of Plasmodium falciparum, which have been associated with resistance to pyrimethamine and sulfadoxine, respectively. Four hundred seventy-four patients were sampled in Kilwa (N = 138), Kisangani (N = 112), Boende (N = 106), and Basankusu (N = 118). The proportion of triple mutations dhfr varied between sites but was always > 50%. The proportion of dhps double mutations was < 20%, with some sites as low as 0.9%. A quintuple mutation was present in 12.8% (16/125) samples in Kilwa; 11.9% (13/109) in Kisangani, 2.9% (3/102) in Boende, and 0.9% (1/112) in Basankusu. These results suggest high resistance to pyrimethamine alone or combined with sulfadoxine. Adding artesunate to SP does not seem a valid alternative to the current monotherapy.

Safety and efficacy of lumefantrine-artemether (Coartem) for the treatment of uncomplicated Plasmodium falciparum malaria in Zambian adults.

BACKGROUND: In Zambia, unacceptably high resistance to commonly used antimalarial drugs prompted the choice of artemether-lumefantrine (AL) as first line treatment for uncomplicated Plasmodium falciparum malaria. Although the safety and efficacy of AL have been extensively documented, no clinical trials had been carried out in Zambia. METHODS: Nine hundred seventy one adult patients with uncomplicated malaria were randomized to either sulfadoxine-pyrimethamine (SP)(486) or AL (485) and followed up for 45 days. Outcome of treatment was defined according to the standard WHO classification. Recurrent parasitaemia were genotyped to distinguish between recrudescence and new infection. RESULTS: Fever at day 3 was significantly lower (AL: 0.9%; 4/455; SP: 3,5%; 15/433; p = 0.007) and the mean haemoglobin at day 45 significantly higher (AL: 134 g/l; SP 130 g/l; p = 0.02) in the AL group. Almost all clinical symptoms cleared faster with AL. Early treatment failure was significantly higher in the SP (25/464) than in the AL (2/463) (OR: 13.1 95% CI: 3.08-55.50; P < 0.001). The rate of new infections was similar in both groups (18 with SP and 19 with AL). Late clinical failure (OR: 2.55; 95% CI: 1.34-4.84; P = 0.004) and late parasitological failure (OR:3.18; 95% CI: 1.25-8.09; P = 0.02) were significantly higher in the SP group. Total treatment failure was significantly higher in the SP group (96/393; 19.3%) as compared to the AL (22/403; 5.4%) group (OR: 4.15; 95% CI: 2.52-6.83; P < 0.001). CONCLUSION: In Zambia, the new first line regimen AL is far more efficacious than SP in treating uncomplicated P. falciparum malaria in adults. Data on safety and efficacy of AL in pregnant women are urgently needed.

Safety and efficacy of dihydroartemisinin/piperaquine (Artekin) for the treatment of uncomplicated Plasmodium falciparum malaria in Rwandan children.

In Rwanda, amodiaquine+sulfadoxine/pyrimethamine (AQ+SP) is the current first-line treatment for malaria, introduced in 2001 as an interim strategy before the future deployment of an artemisinin-based combination treatment (ACT). Dihydroartemisinin/piperaquine (DHA-PQP) is a new co-formulated and well tolerated ACT increasingly used in Southeast Asia where it has proved to be highly effective against Plasmodium falciparum malaria. We tested the efficacy, safety and tolerability of DHA-PQP in children with uncomplicated P. falciparum malaria. A randomised, open trial was carried out in 2003-2004. Seven hundred and sixty-two children aged 12-59 months with uncomplicated P. falciparum malaria were randomly allocated to one of the following treatments: amodiaquine+artesunate; AQ+SP; or DHA-PQP. Patients were followed-up until Day 28 after treatment. Adverse events and clinical and parasitological outcomes were recorded. Children treated with DHA-PQP or AQ+AS had a significantly higher cure rate compared with those treated with amodiaquine+sulfadoxine/pyrimethamine (95.2% and 92.0% vs. 84.7%, respectively). Parasite clearance was significantly faster in children treated with DHA-PQP and AQ+AS compared with those treated with amodiaquine+sulfadoxine/pyrimethamine. The frequency of adverse events was significantly lower in patients treated with DHA-PQP than in those treated with combinations containing amodiaquine. A 3-day treatment with DHA-PQP proved to be efficacious with a good safety and tolerability profile and could be a good candidate for the next first-line treatment.

In-vitro susceptibility of Plasmodium falciparum to monodesethylamodiaquine, dihydroartemisinin and quinine in an area of high chloroquine resistance in Rwanda.

Plasmodium falciparum in-vitro susceptibility to chloroquine (CQ), monodesethylamodiaquine, quinine and dihydroartemisinin was investigated in Rwandan patients with a parasitaemia of at least >or=4000/microl. The study was carried out in November-December 2003. Dihydroartemisinin was the most potent (GM IC(50)=2.6nmol/l, 95% CI 2.2-3.2) among the drugs tested. Resistance to chloroquine was 45% (33/74) and that to monodesethylamodiaquine 7% (5/74). All the tested isolates were susceptible to quinine. The mean IC(50) of monodesethylamodiaquine, quinine and dihydroartemisinin was significantly higher for chloroquine-resistant than for chloroquine-sensitive strains (P<0.05). The IC(50) of each drug was significantly and positively correlated to that of the other three drugs (P<0.005), and this correlation was higher between CQ and monodesethylamodiaquine (r=0.8). In-vitro CQ resistance is linked to that of the other drugs tested. Most worrying is the positive correlation between the IC(50) of dihydroartemisinin and the other drugs, more particularly with CQ, suggesting an increased tolerance of the parasites to all drugs.

Four artemisinin-based treatments in African pregnant women with malaria.

BACKGROUND: Information regarding the safety and efficacy of artemisinin combination treatments for malaria in pregnant women is limited, particularly among women who live in sub-Saharan Africa. METHODS: We conducted a multicenter, randomized, open-label trial of treatments for malaria in pregnant women in four African countries. A total of 3428 pregnant women in the second or third trimester who had falciparum malaria (at any parasite density and regardless of symptoms) were treated with artemether-lumefantrine, amodiaquine-artesunate, mefloquine-artesunate, or dihydroartemisinin-piperaquine. The primary end points were the polymerase-chain-reaction (PCR)-adjusted cure rates (i.e., cure of the original infection; new infections during follow-up were not considered to be treatment failures) at day 63 and safety outcomes. RESULTS: The PCR-adjusted cure rates in the per-protocol analysis were 94.8% in the artemether-lumefantrine group, 98.5% in the amodiaquine-artesunate group, 99.2% in the dihydroartemisinin-piperaquine group, and 96.8% in the mefloquine-artesunate group; the PCR-adjusted cure rates in the intention-to-treat analysis were 94.2%, 96.9%, 98.0%, and 95.5%, respectively. There was no significant difference among the amodiaquine-artesunate group, dihydroartemisinin-piperaquine group, and the mefloquine-artesunate group. The cure rate in the artemether-lumefantrine group was significantly lower than that in the other three groups, although the absolute difference was within the 5-percentage-point margin for equivalence. The unadjusted cure rates, used as a measure of the post-treatment prophylactic effect, were significantly lower in the artemether-lumefantrine group (52.5%) than in groups that received amodiaquine-artesunate (82.3%), dihydroartemisinin-piperaquine (86.9%), or mefloquine-artesunate (73.8%). No significant difference in the rate of serious adverse events and in birth outcomes was found among the treatment groups. Drug-related adverse events such as asthenia, poor appetite, dizziness, nausea, and vomiting occurred significantly more frequently in the mefloquine-artesunate group (50.6%) and the amodiaquine-artesunate group (48.5%) than in the dihydroartemisinin-piperaquine group (20.6%) and the artemether-lumefantrine group (11.5%) (P<0.001 for comparison among the four groups). CONCLUSIONS: Artemether-lumefantrine was associated with the fewest adverse effects and with acceptable cure rates but provided the shortest posttreatment prophylaxis, whereas dihydroartemisinin-piperaquine had the best efficacy and an acceptable safety profile. (Funded by the European and Developing Countries Clinical Trials Partnership and others; ClinicalTrials.gov number, NCT00852423.).

Plasmodium falciparum genotyping by microsatellites as a method to distinguish between recrudescent and new infections.

In vivo tests for susceptibility to antimalarial drugs require molecular methods to distinguish recrudescence from new infection. The most commonly used DNA markers (merozoite surface proteins [MSPs]) are under immune selective pressure, which might lead to misclassification. We evaluated immunologically neutral microsatellite markers in blood samples collected during a drug efficacy trial in Rwanda. Fifty percent of the infections classified as recrudescent by MSP were classified as new by microsatellite markers. Reciprocally, 23.3% of infections classified as recrudescent by microsatellite markers were identified as new by MSP. In drug efficacy studies, microsatellite markers should complement MSP genotyping to distinguish a recrudescence from a new infection.