Coartem

The analyses of both prevalence of infection and incidence of clinical episodes were based on a generalised estimating equation (GEE) approach that allowed accurate modelling of both the variation in the outcomes and the correlations between repeated measurements in individual children.
The prevalence of infection at the 8 or 9 weekly bleed time points were analysed using logistic GEE models via the XTLOGIT procedure in STATA 8.0. Preliminary analyses showed that the correlations between measurements in individual children were best modelled using an exchangeable correlation structure. A semi-robust Huber/White/sandwich estimator of variance was used to assure valid standard errors. Best fitting models were determined by backward elimination using Wald's Chi-square tests for individual variables. The analyses of age and spatial trend and predictors of infection were based exclusively on data from double bleed time points (i.e. weeks 9–60) using the combined diagnostic results from both samples (see above). As only one sample was collected at baseline and final bleeds (i.e. weeks 0 and 69), only prevalence data from the first sample collected at double bleed time points was used for the analyses of time trends across the entire time of follow-up. Difference in log-transformed parasite densities among age groups were analysed using a normal GEE model with exchangeable correlation structure and semi-robust variance estimator.
For estimation of incidence of clinical episodes in each 8 or 9 week follow-up interval, clinical malaria episodes were defined as a fever (i.e. axillary temperature >37.5°C) or history of fever during the last 48 hrs in the presence of a light microscopically detectable parasitaemia observed in either passive or active follow-up. Febrile episodes with only LDR-FMA detectable parasitaemia were not considered to be malarial episodes. A density cut-off value for clinical disease was set based on a pyrogenic threshold of 2500 parasites/µl for P. falciparum and 500 parasites/µl for all other species [32] . Moderate and high density episodes were defined as febrile episodes with parasitaemias exceeding the pyrogenic threshold 4 and 20-fold, respectively. For each interval, children were considered at risk from the 1^st day after the 2^nd or only blood sample was taken. Cross-sectional bleed days were thus considered part of the preceding interval and clinical episodes detected during the cross-sectional bleeds were included in that interval. Children were not considered at risk for 2 weeks after treatment with Coartem® and 4 weeks after treatment with AQ plus SP.
As preliminary analyses showed significant overdispersion in the number of episodes per child, a negative binomial model GEE model (based on XTNBREG procedure) was used for the analyses of incidence rates. As in the other GEE models, an exchangeable correlation structure and semi-robust variance estimator were used and best fitting models determined by backward elimination using Wald's Chi-square tests for individual variables. Differences in participant characteristics at enrolment were assessed using Chi-square and Fisher's exact tests. All analyses were done using the STATA 8 statistical software package (College Station, TX).

After obtaining community support and written parental consent, 190 children aged 1–3 yrs from Ilaita 1–7 and Sunuhu 1 and 2 were enrolled in March 2006. Demographic information was collected from all participating children and the location of each child's home was recorded using a hand-held GPS receiver (Garmin 12XL). Each child was clinically examined: axillary temperature was measured using digital thermometers, spleen palpated and a standard questionnaire of common signs and symptoms of malarial illness was administered. Hemoglobin (Hb) was measured using a portable device (HemoCue®, Ångholm, Sweden). A 5 ml venous blood sample was collected using Heparin-Vacutainer® tubes (Becton Dickinson, NJ, USA) and 2 blood slides (thick and thin films) made for determination of malarial infection. Bed net usage of both mother and child was queried. All children with parasitologically confirmed malaria (see below) were treated with Coartem® (arthemeter-lumefantrine); those with moderate to severe anaemia (i.e. Hb <7.5 g/dl) received an antimalarial treatment (Coartem®) plus 4 weeks of iron and folate supplementation according to national treatment guidelines.
As the initial enrolment did not yield the required sample size, the study area was extended to include Kamanokor and Ingamblis villages and 74 further children were enrolled into the study from the 1^st to the 3^rd regular bleed time points (May to September 2006).Enrolment procedures were identical with the exception of the 5 ml venous blood sample, which was not collected from these later enrolments. A 250 µl finger prick blood sample was collected instead.

During the multiple dose stage, participants received the standard dose of ivermectin 200 μg/kg once daily for one, two, or three days, respectively. In the randomized-controlled trial stage, participants received either ivermectin 300 μg/kg once daily for three days or placebo once daily for three days, based on dosage in a previous trial administering ivermectin to Plasmodium-infected participants.²³ (link) The number of tablets for placebo-treated participants equalled the number of tablets for ivermectin-treated participants with identical body weight. Ivermectin and placebo were administered orally with water after intake of butter croissant. Tablets were concealed in neutral plastic bags so that participants were not able to distinguish ivermectin from placebo. Drug administration was done in a separate room by a pharmacy team member to maintain double blinding. The first dose was administered directly after successful eligibility assessment. Subsequent doses were given at the same time point ±30 min on the following two days, when applicable.
Placebo tablets were Winthrop's P-Tabletten Weiss 7 mm Lichtenstein, which do not contain any active ingredient. They were purchased at the University Pharmacy Tübingen, Germany. Ivermectin tablets were MSD's Stromectol 3 mg, purchased in Gabon. No quality analysis was performed on the drug batches used.
At enrolment, participants underwent physical examination with demographic data and medical history recorded. Blood samples were taken for haematology (red blood cell count, haemoglobin, haematocrit, leukocyte count with differential and platelet count), clinical chemistry (AST, ALT, urea, creatinine, CRP, and electrolytes), urinalysis, thick and thin blood smears, and for quantitative polymerase chain reaction (qPCR). Blood pregnancy tests were performed at baseline for female participants. Participants were hospitalized for 72 h. Following discharge from the research centre, participants returned for outpatient visits at days 4, 5, 6, and 7. Participants received rescue medication with artemether-lumefantrine (Novartis Coartem® 80/480) in case of fever (axillary temperature >38.5 °C) in conjunction with any Plasmodium parasitaemia or upon development of danger signs, or severe malaria, or parasitaemia ≥20,000 parasites/μl. All other participants were treated for malaria on day 7. Safety assessments were performed from first drug administration until end of study. These included daily physical examination, vital signs, and inquiry about adverse events (AEs), as well as clinical laboratory tests (haematology, clinical chemistry, urinalysis) upon screening and days 3, 5, and 7. AEs were followed up until resolution.

We enrolled children if they were ≥6 months and <12 years and presented with acute (≤72 h), uncomplicated falciparum malaria and either a positive malaria slide for P. falciparum (mono or mixed infection) of any parasitaemia or a positive rapid diagnostic test (SD-Bioline Malaria-Ag-Pf/Pan™, SD Bioline, S. Korea), and their legal guardian gave signed informed consent to the main study and the pharmacokinetic substudy.
Using tablet strengths of 2.5, 5, 7.5 mg tablets (Centurion Laboratories, Vadodara, India)], the age-based regimen was dosed as: (i) 6 m–<1 y: 1.25 mg, (ii) 1–5 y: 2.5 mg, (iii) 6–9 y: 5 mg, and 10–11 y: 7.5 mg. AL (Coartem®, Novartis, Switzerland) and DHAPP (D-ARTEPP®, Guilin, China) were dosed by weight, according to WHO recommendations, crushed, dissolved in water and given with milk. Children aged ≥5 years in Mbale were given whole primaquine tablets to swallow. Full and half doses of all study drugs were given again, if vomiting occurred within 30 and 60 min, respectively.
There was no formal sample size calculation for this PK component of the main study; rather this depended on the capacity at each site and we aimed for a PK population of at least 200.