Acute Uncomplicated Plasmodium Falciparum Malaria Research Articles

Factors affecting haemoglobin dynamics in African children with acute uncomplicated Plasmodium falciparum malaria treated with single low-dose primaquine or placebo

BackgroundSingle low-dose primaquine (SLDPQ) effectively blocks the transmission of Plasmodium falciparum malaria, but anxiety remains regarding its haemolytic potential in patients with glucose-6-phopshate dehydrogenase (G6PD) deficiency. We, therefore, examined the independent effects of several factors on haemoglobin (Hb) dynamics in falciparum-infected children with a particular interest in SLDPQ and G6PD status.MethodsThis randomised, double-blind, placebo-controlled, safety trial was conducted in Congolese and Ugandan children aged 6 months–11 years with acute uncomplicated P. falciparum and day (D) 0 Hbs ≥ 6 g/dL who were treated with age-dosed SLDPQ/placebo and weight-dosed artemether lumefantrine (AL) or dihydroartemisinin piperaquine (DHAPP). Genotyping defined G6PD (G6PD c.202T allele), haemoglobin S (HbS), and α-thalassaemia status.Multivariable linear and logistic regression assessed factor independence for continuous Hb parameters and Hb recovery (D42 Hb > D0 Hb), respectively.ResultsOne thousand one hundred thirty-seven children, whose median age was 5 years, were randomised to receive: AL + SLDPQ (n = 286), AL + placebo (286), DHAPP + SLDPQ (283), and DHAPP + placebo (282). By G6PD status, 284 were G6PD deficient (239 hemizygous males, 45 homozygous females), 119 were heterozygous females, 418 and 299 were normal males and females, respectively, and 17 were of unknown status.The mean D0 Hb was 10.6 (SD 1.6) g/dL and was lower in younger children with longer illnesses, lower mid-upper arm circumferences, splenomegaly, and α-thalassaemia trait, who were either G6PDd or heterozygous females. The initial fractional fall in Hb was greater in younger children with higher D0 Hbs and D0 parasitaemias and longer illnesses but less in sickle cell trait. Older G6PDd children with lower starting Hbs and greater factional falls were more likely to achieve Hb recovery, whilst lower D42 Hb concentrations were associated with younger G6PD normal children with lower fractional falls, sickle cell disease, α-thalassaemia silent carrier and trait, and late treatment failures. Ten blood transfusions were given in the first week (5 SLDPQ, 5 placebo).ConclusionsIn these falciparum-infected African children, posttreatment Hb changes were unaffected by SLDPQ, and G6PDd patients had favourable posttreatment Hb changes and a higher probability of Hb recovery. These reassuring findings support SLDPQ deployment without G6PD screening in Africa.Trial registrationThe trial is registered at ISRCTN 11594437.

Significant Efficacy of a Single Low Dose of Primaquine Compared to Stand-Alone Artemisinin Combination Therapy in Reducing Gametocyte Carriage in Cambodian Patients with Uncomplicated Multidrug-Resistant Plasmodium falciparum Malaria.

Since 2012, a single low dose of primaquine (SLDPQ; 0.25 mg/kg of body weight) with artemisinin-based combination therapies has been recommended as the first-line treatment of acute uncomplicated Plasmodium falciparum malaria to interrupt its transmission, especially in low-transmission settings of multidrug resistance, including artemisinin resistance. Policy makers in Cambodia have been reluctant to implement this recommendation due to primaquine safety concerns and a lack of data on its efficacy. In this randomized controlled trial, 109 Cambodians with acute uncomplicated P. falciparum malaria received dihydroartemisinin-piperaquine (DP) alone or combined with SLDPQ on the first treatment day. The transmission-blocking efficacy of SLDPQ was evaluated on days 0, 1, 2, 3, 7, 14, 21, and 28, and recrudescence by reverse transcriptase PCR (RT-PCR) (gametocyte prevalence) and membrane feeding assays with Anopheles minimus mosquitoes (gametocyte infectivity). Without the influence of recrudescent infections, DP-SLDPQ reduced gametocyte carriage 3-fold compared to that achieved with DP. Of 48 patients tested on day 0, only 3 patients were infectious to mosquitoes (∼6%). Posttreatment, three patients were infectious on day 14 (3.5%, 1/29) and on the 1st and 7th days of recrudescence (8.3%, 1/12 for each); this overall low infectivity precluded our ability to assess its transmission-blocking efficacy. Our study confirms the effective gametocyte clearance of SLDPQ when combined with DP in multidrug-resistant P. falciparum infections and the negative impact of recrudescent infections due to poor DP efficacy. Artesunate-mefloquine (ASMQ) has replaced DP, and ASMQ-SLDPQ has been deployed to treat all patients with symptomatic P. falciparum infections to further support the elimination of multidrug-resistant P. falciparum in Cambodia. (This study has been registered at ClinicalTrials.gov under identifier NCT02434952.).

Pharmacokinetics, Safety, Tolerability and Efficacy of a New Artemether-lumefantrine Dispersible Tablet in Infants and Neonates <5 kg Body Weight With Acute Uncomplicated Plasmodium Falciparum Malaria

Pharmacokinetics, Safety, Tolerability and Efficacy of a New Artemether-lumefantrine Dispersible Tablet in Infants and Neonates <5 kg Body Weight With Acute Uncomplicated Plasmodium Falciparum Malaria

Population pharmacokinetics of mefloquine given as a 3-day artesunate\u2013mefloquine in patients with acute uncomplicated Plasmodium falciparum malaria in a multidrug-resistant area along the Thai\u2013Myanmar border

BackgroundLow mefloquine exposure has been shown to contribute to treatment failure in patients with uncomplicated falciparum malaria following a 3-day artesunate–mefloquine combination. The present study aimed to develop a population pharmacokinetic model for mefloquine based on whole blood concentration–time profiles of this target population for further dose optimization.MethodsA total of 129 Burmese patients aged above 15 years who presented with typical symptoms of malaria and had a blood smear positive for Plasmodium falciparum were included in the study. All were treated with the standard 3-day combination regimen of artesunate and mefloquine consisting of mefloquine for 2 days and artesunate for 3 days. Blood samples were collected before and at different time points after drug administration from different sub-groups of patients. Mefloquine concentrations were quantified in whole blood using high-performance liquid chromatography. A non-linear mixed-effect modelling approach was applied for population pharmacokinetic analysis using the NONMEM v7.3 software. Covariates investigated (body weight, gender, admission parasitaemia, and molecular markers of mefloquine resistance) were investigated in a step-wise manner using the SCM functionality in Perl-Speaks-NONMEM.ResultsPopulation pharmacokinetic analysis of mefloquine was performed in all patients with a total of 653 samples. Whole blood mefloquine concentration–time profiles were described by a two-compartment disposition model. Of the covariates investigated, none was found to have a significant impact on the pharmacokinetics of mefloquine. Significant differences in maximum concentration (Cmax) and elimination half-life (t1/2) were found in patients who had treatment failure (36 cases) compared to patients with successful treatment (107 cases).ConclusionThe study successfully describes the pharmacokinetics of mefloquine following a 2-day treatment of mefloquine as a part of a 3-day artesunate–mefloquine in patients with uncomplicated falciparum malaria from Thailand. A model has been developed which adequately describes the pharmacokinetics of mefloquine. More extensive clinical studies including both adults and children are needed to fully characterize the pharmacokinetics of mefloquine.

In vitro sensitivity of antimalarial drugs and correlation with clinico-parasitological response following treatment with a 3-day artesunate-mefloquine combination in patients with falciparum malaria along the Thai-Myanmar border

A 3-day artesunate-mefloquine combination therapy has been using as first-line treatment for acute uncomplicated Plasmodium falciparum malaria in Thailand since 1995 on the background of mefloquine resistance. The aim of the present study was to assess sensitivity of P. falciparum isolates (n=44) in an area along the Thai-Myanmar border (year 2009) to artesunate, mefloquine, chloroquine and quinine, including their correlation with clinico-parasitological response. Twenty, 19, and 5 isolates were collected from patients with ‘Adequate Clinical and Parasitological Response (ACPR)’, ‘Late Parasitological Failure (LPF)’ and ‘re-infection’, respectively. The IC50 of artesunate and mefloquine were significantly higher in patients with LPF compared with ACPR and re-infection. The proportion of isolates with declined artesunate or mefloquine sensitivity in the LPF group (47.4%) was significantly higher than the ACPR group (5.0%). A weak but statistical significant correlation (r=0.384, p=0.01) was observed between IC50 values of artesunate and parasite clearance time (PCT). There was no significant relationship between in vitro sensitivity of parasite isolates to chloroquine or quinine and clinical response. In vitro susceptibility of P. falciparum isolates to artesunate and mefloquine may be used as a useful reliable tool to predict clinico-pathological response following a 3-day artesunate-mefloquine combination therapy.

Adding a single low-dose of primaquine (0.25mg/kg) to artemether-lumefantrine did not compromise treatment outcome of uncomplicated Plasmodium falciparum malaria in Tanzania: a randomized, single-blinded clinical trial.

BackgroundThe World Health Organization (WHO) recently recommended the addition of a single low-dose of the gametocytocidal drug primaquine (PQ) to artemisinin-based combination therapy (ACT) in low transmission settings as a component of pre-elimination or elimination programmes. However, it is unclear whether that influences the ACT cure rate. The study assessed treatment outcome of artemether-lumefantrine (AL) plus a single PQ dose (0.25 mg/kg) versus standard AL regimen for treatment of acute uncomplicated Plasmodium falciparum malaria in Tanzania.MethodsA randomized, single-blinded, clinical trial was conducted in Yombo, Bagamoyo district, Tanzania. Acute uncomplicated P. falciparum malaria patients aged ≥1 year, with the exception of pregnant and lactating women, were enrolled and treated with AL plus a single PQ dose (0.25 mg/kg) or AL alone under supervision. PQ was administered together with the first AL dose. Clinical and laboratory assessments were performed at 0, 8, 24, 36, 48, 60, and 72 h and on days 7, 14, 21, and 28. The primary end-point was a polymerase chain reaction (PCR)-adjusted adequate clinical and parasitological response (ACPR) on day 28. Secondary outcomes included: fever and asexual parasitaemia clearance, proportion of patients with PCR-determined parasitaemia on day 3, and proportion of patients with Pfmdr1 N86Y and Pfcrt K76T on days 0, 3 and day of recurrent infection.ResultsOverall 220 patients were enrolled, 110 were allocated AL + PQ and AL, respectively. Parasite clearance by microscopy was fast, but PCR detectable parasitaemia on day 3 was 31/109 (28.4 %) and 29/108 (26.9 %) in patients treated with AL + PQ and AL, respectively (p = 0.79). Day 28 PCR-adjusted ACPR and re-infection rate was 105/105 (100 %) and 101/102 (99 %) (p = 0.31), and 5/107 (4.7 %) and 5/8 (4.8 %) (p = 0.95), in AL + PQ and AL arm, respectively. There was neither any statistically significant difference in the proportion of Pfmdr1 N86Y or Pfcrt K76T between treatment arms on days 0, 3 and day of recurrent infection, nor within treatment arms between days 0 and 3 or day 0 and day of recurrent infection.ConclusionThe new WHO recommendation of adding a single low-dose of PQ to AL did not compromise treatment outcome of uncomplicated P. falciparum malaria in Tanzania.Trial registration number NCT02090036Electronic supplementary materialThe online version of this article (doi:10.1186/s12936-016-1430-3) contains supplementary material, which is available to authorized users.

Safety of a single low-dose of primaquine in addition to standard artemether-lumefantrine regimen for treatment of acute uncomplicated Plasmodium falciparum malaria in Tanzania.

BackgroundThis study assessed the safety of the new World Health Organization (WHO) recommendation of adding a single low-dose of primaquine (PQ) to standard artemisinin-based combination therapy (ACT), regardless of individual glucose-6-phosphate dehydrogenase (G6PD) status, for treatment of acute uncomplicated Plasmodium falciparum malaria in Tanzania.MethodsMen and non-pregnant, non-lactating women aged ≥1 year with uncomplicated P. falciparum malaria were enrolled and randomized to either standard artemether-lumefantrine (AL) regimen alone or with a 0.25 mg/kg single-dose of PQ. PQ was administered concomitantly with the first AL dose. All drug doses were supervised. Safety was evaluated between days 0 and 28. G6PD status was assessed using rapid test (CareStart™) and molecular genotyping. The primary endpoint was mean percentage relative reduction in haemoglobin (Hb) concentration (g/dL) between days 0 and 7 by genotypic G6PD status and treatment arm.ResultsOverall, 220 patients, 110 per treatment arm, were enrolled, of whom 33/217 (15.2 %) were phenotypically G6PD deficient, whereas 15/110 (13.6 %) were genotypically hemizygous males, 5/110 (4.5 %) homozygous females and 22/110 (20 %) heterozygous females. Compared to genotypically G6PD wild-type/normal [6.8, 95 % confidence interval (CI) 4.67–8.96], only heterozygous patients in AL arm had significant reduction in day-7 mean relative Hb concentration (14.3, 95 % CI 7.02-21.55, p=0.045), however, none fulfilled the pre-defined haemolytic threshold value of ≥25 % Hb reduction. After adjustment for baseline parasitaemia, Hb, age and sex the mean relative Hb reduction was not statistically significant in both heterozygous and hemizygous/homozygous patients in both arms. A majority of the adverse events (AEs) were mild and unrelated to the study drugs. However, six (4.4 %) episodes, three per treatment arm, of acute haemolytic anaemia occurred between days 0 and 7. Three occurred in phenotypically G6PD deficient patients, two in AL and one in AL + PQ arm, but none in genotypically hemizygous/homozygous patients. All patients with acute haemolytic anaemia recovered without medical intervention.ConclusionThe findings support that the WHO recommendation of adding a single low-dose of PQ to standard AL regimen is safe for the treatment of acute uncomplicated P. falciparum malaria regardless of G6PD status in Tanzania.Trial registration number NCT02090036Electronic supplementary materialThe online version of this article (doi:10.1186/s12936-016-1341-3) contains supplementary material, which is available to authorized users.

Transient lesion in the splenium of the corpus callosum in acute uncomplicated falciparum malaria.

Patients with acute uncomplicated Plasmodium falciparum malaria have no evident neurologic disorder, vital organ dysfunction, or other severe manifestations of infection. Nonetheless, parasitized erythrocytes cytoadhere to the endothelium throughout their microvasculature, especially within the brain. We aimed to determine if 3 Tesla magnetic resonance imaging studies could detect evidence of cerebral abnormalities in these patients. Within 24 hours of admission, initial magnetic resonance imaging examinations found a lesion with restricted water diffusion in the mid-portion of the splenium of the corpus callosum of 4 (40%) of 10 male patients. The four patients who had a splenial lesion initially had evidence of more severe hemolysis and thrombocytopenia than the six patients who had no apparent abnormality. Repeat studies four weeks later found no residua of the lesions and resolution of the hematologic differences. These observations provide evidence for acute cerebral injury in the absence of severe or cerebral malaria.

How Reliable Are Hematological Parameters in Predicting Uncomplicated Plasmodium falciparum Malaria in an Endemic Region?

BackgroundMalaria remains endemic in Sub-Saharan Africa. Hematological changes that occur have been suggested as potential predictors of malaria. This study was aimed at evaluating the diagnostic relevance of hematological parameters in predicting malaria.MethodsA cross-sectional study involving 370 patients with signs and symptoms of malaria was conducted at Mulago Hospital, Kampala, from May, 2012 to February, 2013. Thin and thick blood films were prepared for each patient and stained with Giemsa to aid the detection of malaria parasites. Patients’ hematological parameters were determined.ResultsOut of the 370 patients, 61 (16.5%) had malaria. Significant differences in the hematological parameters between P. falciparum malaria parasitemic patients and nonparasitemic patients were only observed in mean (±SD) of the differential monocyte count (10.89 ± 6.23% versus 8.98 ± 5.02%, p = 0.01) and the platelet count (172.43 (± 80.41) ×103 cells/μl versus 217.82 ± (95.96) ×103 cells/μl p = 0.00). The mean (±SD) values of the red blood cell indices (hemoglobin count, MCV, MCH, and MCHC), the differential neutrophil and lymphocyte counts, and the mean platelet volume (MPV) did not significantly differ between the two groups.ConclusionHematological changes are unreliable laboratory indicators of malaria in acute uncomplicated Plasmodium falciparum malaria.

Safety and efficacy of pyronaridine-artesunate in uncomplicated acute malaria: an integrated analysis of individual patient data from six randomized clinical trials

BackgroundPyronaridine-artesunate (PA) is indicated for the treatment of acute uncomplicated Plasmodium falciparum and Plasmodium vivax malaria.MethodsIndividual patient data on safety outcomes were integrated from six randomized clinical trials conducted in Africa and Asia in patients with microscopically confirmed P. falciparum (five studies) or P. vivax (one study) malaria. Efficacy against P. falciparum was evaluated across three Phase III clinical trials.ResultsThe safety population included 2,815 patients randomized to PA, 1,254 to comparators: mefloquine + artesunate (MQ + AS), artemether-lumefantrine (AL), or chloroquine. All treatments were generally well tolerated. Adverse events occurred in 57.2% (1,611/2,815) of patients with PA versus 51.5% (646/1,254) for comparators, most commonly (PA; comparators): headache (10.6%; 9.9%), cough (5.9%; 5.6%) and anaemia (4.5%; 2.9%). Serious averse events were uncommon for all treatments (0–0.7%). Transient increases in alanine aminotransferase and aspartate aminotransferase were observed with PA but did not lead to any clinical sequelae. For P. falciparum malaria, day-28 PCR-corrected adequate clinical and parasitological response with PA was 93.6% ([1,921/2,052] 95% CI 92.6, 94.7) in the intent-to-treat population and 98.5% ([1,852/1,880] 95% CI 98.0, 99.1) in the per-protocol population. Median parasite clearance time was 24.1 h with PA, 31.9 h with MQ + AS, and 24.0 h with AL. Median fever clearance time was 15.5 h with PA, 15.8 h with MQ + AS, and 14.0 h with AL. By day 42, P. falciparum gametocytes had declined to near zero for all treatments.ConclusionsPyronaridine-artesunate was well tolerated with no safety concerns with the exception of mostly mild transient rises in transaminases. Efficacy was high and met the requirements for use as first-line therapy. Pyronaridine-artesunate should be considered for inclusion in malaria treatment programmes.Trial registrationClinicaltrials.gov: NCT00331136; NCT00403260; NCT00422084; NCT00440999; NCT00541385; NCT01594931

Safety, efficacy and population pharmacokinetics of fixed-dose combination of artesunate-mefloquine in the treatment of acute uncomplicated Plasmodium falciparum malaria in India

Safety, efficacy and population pharmacokinetics of fixed-dose combination of artesunate-mefloquine in the treatment of acute uncomplicated Plasmodium falciparum malaria in India

Therapeutic Efficacy of Artesunate–Amodiaquine Combinations and the Plasma and Saliva Concentrations of Desethylamodiaquine in Children With Acute Uncomplicated Plasmodium falciparum Malaria

The treatment efficacy of artesunate-amodiaquine (AQ) coformulated or copackaged, and the plasma and saliva concentrations of desethylamodiaquine (DEAQ), the active metabolite of AQ, were evaluated in 120 and 7 children, respectively, with uncomplicated Plasmodium falciparum malaria treated with oral daily doses of the 2 formulations for 3 days. All children recovered clinically. Fever clearance (1.1 ± 0.2 vs 1.0 ± 0 days) and parasite clearance times (21.1 ± 10.2 vs 19.0 ± 7.0 hours) in artesunate-AQ coformulated and artesunate-AQ copackaged treated children, respectively, were similar. All children remained aparasitemic for at least 28 days. Blood and saliva samples were collected over 35 days and DEAQ in plasma and saliva was determined by high-performance liquid chromatography. DEAQ was detectable in plasma and saliva within 40 minutes of oral administration of artesunate-AQ. DEAQ concentrations 7 days after the start of therapy were 247.8 and 125.1 ng/mL in plasma and saliva, respectively. The concentration-time curves of plasma and saliva in declining phases were approximately parallel giving a similar half-life of 169.1 ± 16.4 and 142.8 ± 6.5 hours in plasma and saliva, respectively. Clearance from plasma and saliva was also similar (335.6 and 443.4 mL·h·kg, respectively). Area under concentration-time curves (AUC0-35d) for plasma and saliva were 94,744.9 and 74,004.2 ng·mL·h, respectively. In general, Saliva-plasma concentration ratio was 0.25-0.4. DEAQ concentrations in saliva may be useful for monitoring therapy and for the evaluation of the disposition of AQ in children with falciparum malaria treated with AQ-based combination.

Efficacy and tolerability of a new formulation of artesunate-mefloquine for the treatment of uncomplicated malaria in adult in Senegal: open randomized trial

BackgroundPrompt treatment of malaria attacks with arteminisin-based combination therapy (ACT) is an essential tool for malaria control. A new co-blister tablet of artesunate-mefloquine (AM) with 25 mg/kg mefloquine has been developed for the management of uncomplicated malaria attacks. This non-inferiority randomized trial, was conducted to evaluate the efficacy and safety of the new formulation of AM in comparison to artemether-lumefantrine (AL) for the treatment of acute uncomplicated Plasmodium falciparum malaria in adults in Senegal.MethodsThe study was carried out from September to December 2010 in two health centres in Senegal. The study end points included (i) PCR corrected adequate clinical and parasitological response (ACPR) at day 28, (ii) ACPR at days 42 and 63, (iii) parasites and fever clearance time, (iv) incidence of adverse events and patients biological profile at day 7 using the WHO 2003 protocol for anti-malarial drug evaluation.ResultsOverall, 310 patients were randomized to receive either AM (n = 157) or AL (n = 153). PCR corrected ACPR at day 28 was at 95.5% in the AM arm while that in the AL arm was at 96.7% (p = 0.83). Therapeutic efficacy was at 98.5% in the AM arm versus 98.2% in the AL group at day 42 (p = 1). At day 63, ACPR in the AM and AL arms was at 98.2% and 97.7%, respectively (p = 0.32). The two treatments were well tolerated with similar biological profile at day 7. However, dizziness was more frequent in the AM arm.ConclusionArtesunate-mefloquine (25 mg/Kg mefloquine) is efficacious and well-tolerated for the treatment of uncomplicated P. falciparum malaria in adult patients.

Therapeutic Efficacy of Artemether-Lumefantrine for the Treatment of Uncomplicated Plasmodium falciparum Malaria in Northern Ethiopia

Introduction. Multidrug resistance of Plasmodium falciparum is spreading throughout Africa. This has posed major challenges to malaria control in sub-Saharan Africa. Objective. The aim of the study was to evaluate the efficacy of artemether-lumefantrine for the treatment of uncomplicated Plasmodium falciparum malaria in North Ethiopia. Methods. This prospective study was undertaken during August–November 2009 on 71 malaria patients that fulfilled the inclusion criteria set by the WHO. Patients were followed up for 28 days. Thick and thin blood films were prepared by Giemsa stain for microscopy to determine parasite density. A standard six-dose regimen of artemether-lumefantrine was administered over three days and was followed up with clinical and parasitological evaluations over 28 days. Results. The cure rate (ACPR) was found to be high (97.2%) in this study. The parasite and fever clearance time was also rapid. Artemether-lumefantrine for the treatment of acute uncomplicated Plasmodium falciparum malaria in the study area showed 97.2% cure rate and only 2.8% failure rate. Conclusion. The result showed that the drug could continue as first line for the treatment of uncomplicated Plasmodium falciparum malaria in the study area. The efficacy of artemether-lumefantrine needs to be carefully monitored periodically in sentinel sites representing different areas of the country.

Hematologic Parameters in Pediatric Uncomplicated Plasmodium falciparum Malaria in Sub-Saharan Africa

Hematologic changes in acute and convalescent uncomplicated Plasmodium falciparum malaria have not been well studied, particularly in young children in Africa. Hematologic data were obtained for 3,044 children less than five years of age in seven randomized controlled trials at 14 sites. Using paired analysis between day 28 and baseline in patients without parasitologic failure as a proxy for malaria-induced effects, we found a statistically significant but clinically modest increase in leukocyte counts (5%) resulting from a larger increase in neutrophils (43%) than the decrease in lymphocytes counts (-16%); levels of hemoglobin and platelets decreased (-13% and -49%, respectively). Multivariate random effects analysis showed trends during follow-up (increased levels of hemoglobin, platelets and lymphocytes, and decreased levels of leukocytes and neutrophils) and identified explanatory variables. The risk of neutropenia increased with follow-up time independent of treatment outcome, and was lower with age, higher baseline parasitemia, and artemisinin combination treatment. These analyses provides information on hematologic variations caused by malaria.

Efficacy and Effectiveness of Artemether-Lumefantrine after Initial and Repeated Treatment in Children < 5 Years of Age with Acute Uncomplicated Plasmodium falciparum Malaria in Rural Tanzania: A Randomized Trial

We assessed the efficacy, effectiveness and safety of artemether-lumefantrine, which is the most widely used artemisinin-based combination therapy in Africa, against Plasmodium falciparum malaria during an extended follow-up period after initial and repeated treatment. We performed an open-label randomized trial of artemether-lumefantrine with supervised (n=180) and unsupervised intake (n=179) in children <5 years of age with uncomplicated falciparum malaria in rural Tanzania. Recurrent infections between day 14 and day 56 were retreated within the same study arm. Main end points were polymerase chain reaction (PCR)-corrected cure rates by day 56 and day 42 after initial and repeated treatment, respectively, as estimated by survival analysis. The PCR-corrected cure rate after initial treatment was 98.1% (95% confidence interval [CI], 94.2%-99.4%) after supervised and 95.1% (95% CI, 90.7%-98.1%) after unsupervised intake (P=.29). After retreatment of recurrent infections, the cure rates were 92.9% (95% CI, 81.8%-97.3%) and 97.6% (95% CI, 89.3%-98.8%), respectively (P=.58). Reinfections occurred in 46.9% (82 of 175) versus 50.9 % of the patients (relative risk [RR], 0.92 [95% CI, 0.74-1.14]; P=.46) after initial therapy and 32.4% (24 of 74) versus 39.0% (32 of 82) (RR, 0.83 [95% CI, 0.54-1.27]; P=.39) after retreatment. Median blood lumefantrine concentrations in supervised and unsupervised patients on day 7 were 304 versus 194 ng/mL (P<.001) after initial treatment and 253 versus 164 ng/mL (P=.001) after retreatment. Vomiting was the most commonly reported drug-related adverse event (in 1% of patients) after both initial and repeated treatment. Artemether-lumefantrine was highly efficacious even after unsupervised administration, despite significantly lower lumefantrine concentrations, compared with concentration achieved with supervised intake, and was well-tolerated and safe after initial and repeated treatment. ISRCTN69189899.

Declining in efficacy of a three-day combination regimen of mefloquine-artesunate in a multi-drug resistance area along the Thai-Myanmar border

BackgroundDeclining in clinical efficacy of artesunate-mefloquine combination has been documented in areas along the eastern border (Thai-Cambodian) of Thailand. In the present study, the clinical efficacy of the three-day combination regimen of artesunate-mefloquine as first-line treatment for acute uncomplicated falciparum malaria in Thailand was monitored in an area along the western border (Thai-Myanmar) of the country.MethodsA total of 150 Burmese patients (85 males and 65 females) aged between 16 and 50 years who were attending the Mae Tao clinic, Mae-Sot, Tak Province, and presenting with symptomatic acute uncomplicated Plasmodium falciparum malaria were included into the study. Patients were treated initially (day 0) with 4 mg/kg body weight artesunate and 15 mg/kg body weight mefloquine. The dose regimen on day 2 was 4 mg/kg body weight artesunate and 10 mg/kg body weight mefloquine. On day 3, artesunate at the dose of 4 mg/kg body weight was given with 0.6 mg/kg body weight primaquine. Whole blood mefloquine and plasma artesunate and dihydroartemisinin (active plasma metabolite of artesunate) concentrations following treatment were determined by high performance liquid chromatography (HPLC) and liquid chromatography-mass spectrometry (LCMS), respectively.ResultsThirty-four cases had recrudescence during days 7 and 42. Five and 5 cases, respectively had reinfection with P. falciparum and reappearance of Plasmodium vivax in their peripheral blood during follow-up. The Kaplan-Meier estimate of the 42-and 28-day efficacy rates of this combination regimen were 72.58% (95% CI: 63.20-79.07%) and 83.06 (95% CI 76.14-94.40%), respectively. Parasite clearance time (PCT) and fever clearance time (FCT) were significantly prolonged in patients with treatment failure compared with those with sensitive response [median (95% CI) values for PCT 32.0 (20.0-48.0) vs 24.0 (14.0-32.0) hr and FCT 30.0 (22.0-42.0) vs 26.0 (18.0-36.0) hr; p < 0.005]. Whole blood mefloquine concentrations on days 1, 7 and 14 in patients with sensitive and recrudescence response were comparable. Although plasma concentration of dihydroartemisinin at 1 hour of treatment was significantly lower in patients with recrudescence compared with sensitive response [mean (95% CI) 456 (215-875) vs 525 (452-599) ng/ml; p < 0.001], the proportion of patients with recrudescence who had relatively low (compared with the lower limit of 95% CI defined in the sensitive group) was significantly smaller than that of the sensitive group.ConclusionsAlthough pharmacokinetic (ethnic-related) factors including resistance of P. falciparum to mefloquine contribute to some treatment failure following treatment with a three-day combination regimen of artesunate-mefloquine, results suggest that artesunate resistance may be emerging at the Thai-Myanmar border.

Study on association between genetic polymorphisms of haem oxygenase-1, tumour necrosis factor, cadmium exposure and malaria pathogenicity and severity

BackgroundMalaria is the most important public health problems in tropical and sub-tropical countries. Haem oxygenase (HO) enzyme and the pro-inflammatory cytokine tumour necrosis factor (TNF) have been proposed as one of the factors that may play significant role in pathogenicity/severity of malaria infection. HO is the enzyme of the microsomal haem degradation pathway that yields biliverdin, carbon monoxide, and iron. In this study, the association between malaria disease pathogenicity/severity and (GT)n repeat polymorphism in the promoter region of the inducible HO-1 including the effect of cadmium exposure (potent inducer of HO-1 transcription) as well as polymorphism of TNF were investigated.MethodsBlood samples were collected from 329 cases non-severe malaria with acute uncomplicated Plasmodium falciparum malaria (UM) and 80 cases with Plasmodium vivax malaria (VM), and 77 cases with severe or cerebral malaria (SM) for analysis of genetic polymorphisms of HO-1 and TNF and cadmium levels. These patients consisted of 123 (25.3%) Thai, 243 (50.0%) Burmese and 120 (24.7%) Karen who were present at Mae Sot General Hospital, Mae Sot, Tak Province, Thailand.ResultsThe number of (GT)n repeats of the HO-1 gene in all patients varied between 16 and 39 and categorized to short (S), medium (M) and long (L) GTn repeats. The genotype of (GT)n repeat of HO-1 was found to be significantly different among the three ethnic groups of patients. Significantly higher frequency of S/L genotype was found in Burmese compared with Thai patients, while significantly lower frequencies of S/S and M/L but higher frequency of M/M genotype was observed in Burmese compared with Karen patients. No significant association between HO-1 and TNF polymorphisms including the inducing effect of cadmium and malaria pathogenicity/severity was observed.ConclusionsDifference in the expression of HO-1 genotype in different ethnic groups may contribute to different severity of malaria disease. With this limited sample size, the finding of the lack of association between malaria disease pathogenicity/severity genetic polymorphisms of HO-1 (GT)n repeat as well as TNF observed in this study may not entirely exclude their possible link with malaria disease pathogenicity/severity. Further study in larger sample size is required.

Effectiveness of five artemisinin combination regimens with or without primaquine in uncomplicated falciparum malaria: an open-label randomised trial

SummaryBackgroundArtemisinin-combination therapy (ACT) is recommended as first-line treatment of falciparum malaria throughout the world, and fixed-dose combinations are preferred by WHO; whether a single gametocytocidal dose of primaquine should be added is unknown. We aimed to compare effectiveness of four fixed-dose ACTs and a loose tablet combination of artesunate and mefloquine, and assess the addition of a single gametocytocidal dose of primaquine.MethodsIn an open-label randomised trial in clinics in Rakhine state, Kachin state, and Shan state in Myanmar (Burma) between Dec 30, 2008, and March 20, 2009, we compared the effectiveness of all four WHO-recommended fixed-dose ACTs (artesunate–mefloquine, artesunate–amodiaquine, dihydroartemisinin–piperaquine, artemether–lumefantrine) and loose artesunate–mefloquine in Burmese adults and children. Eligible patients were those who presented to the clinics with acute uncomplicated Plasmodium falciparum malaria or mixed infection, who were older than 6 months, and who weighed more than 5 kg. Treatments were randomised in equal numbers within blocks of 50 and allocation was in sealed envelopes. All patients were also randomly assigned to receive either a single dose of primaquine 0·75 mg base/kg or not. Patients were followed up for 63 days. Treatment groups were compared by analysis of variance and multiple logistic regression. The primary outcome was the 63 day recrudescence rate. This study is registered with clinicaltrials.gov, number NCT00902811.Findings155 patients received artesunate–amodiaquine, 162 artemether–lumefantrine, 169 artesunate–mefloquine, 161 loose artesunate–mefloquine, and 161 dihydroartemisinin–piperaquine. By day 63 of follow-up, 14 patients (9·4%; 95% CI 5·7–15·3%) on artesunate–amodiaquine had recrudescent P falciparum infections, a rate significantly higher than for artemether–lumefantrine (two patients; 1·4%; 0·3–5·3; p=0·0013), fixed-dose artesunate–mefloquine (0 patients; 0–2·3; p<0·0001), loose artesunate–mefloquine (two patients; 1·3%; 0·3–5·3; p=0·0018), and dihydroartemisinin–piperaquine (two patients 1·3%; 0·3–5·2%; p=0·0012). Hazard ratios for re-infection (95% CI) after artesunate–amodiaquine were 3·2 (1·3–8·0) compared with the two artesunate–mefloquine groups (p=0·01), 2·6 (1·0–6–0) compared with artemether–lumefantrine (p=0·04), and 2·3 (0·9–6·0) compared with dihydroartemisinin–piperaquine (p=0·08). Mixed falciparum and vivax infections were common: 129 (16%) had a mixed infection at presentation and 330 (41%) patients had one or more episodes of Plasmodium vivax infection during follow-up. The addition of a single dose of primaquine (0·75 mg/kg) reduced P falciparum gametocyte carriage substantially: rate ratio 11·9 (95% CI 7·4–20·5). All regimens were well tolerated. Adverse events were reported by 599 patients, most commonly vomiting and dizziness. Other side-effects were less common and were not related to a specific treatment.InterpretationArtesunate–amodiaquine should not be used in Myanmar, because the other ACTs are substantially more effective. Artesunate–mefloquine provided the greatest post-treatment suppression of malaria. Adding a single dose of primaquine would substantially reduce transmission potential. Vivax malaria, not recurrent falciparum malaria, is the main complication after treatment of P falciparum infections in this region.FundingMédecins sans Frontières (Holland) and the Wellcome Trust Mahidol University Oxford Tropical Medicine Research Programme.

Open comparative efficacy of some artemisinin-based combinations for treatment of acute uncomplicated plasmodium falciparum malaria in Ilorin Nigeria

Widespread resistance of Plasmodium falciparum to chloroquine and sulfadoxinepyrimethamine has prompted the federal government of Nigeria, in line with WHO recommendations to adopt artemisinin-based combinations as first-line treatment of acute uncomplicated Plasmodium falciparum malaria. We evaluated 3 artemisinin-based combinations available in the Nigerian market to determine their efficacy and tolerability. Adequate clinical and parasitological response (ACPR) was comparable between artemetherlumefantrine (A-L) and artesunate-amodiaquine (AS-AQ) groups (92.8% v 91.2%, p = 0.79), both combinations being significantly more efficacious than artesunate-sulfadoxinepyrimethamine (AS-SP) group (A-L v AS-SP 92.8% v 69%; p = 0.005); (AS-AQ v AS-SP 91.2% v 69%; p = 0.018). Drug-related adverse events were significantly higher among the AS-AQ group compared to other treatment combinations (p = 0.004). We conclude that A-L and ASAQ have high comparative cure rates among patients evaluated in ilorin, Nigeria. Tolerability concern should play an important consideration when prescribing AS-AQ especially among adult patients.