The objective of this study was to monitor the effectiveness of artesunate-amodiaquine fixed-dose combination tablets (ASAQ Winthrop®) in the treatment of uncomplicated
Artemisinin-based combination therapy (ACT) has become the standard for antimalarial therapy worldwide and is recommended by the World Health Organization (WHO) as first-line treatment for uncomplicated
Despite widespread use of ACT since 2001, emergence of ACT resistance in Africa has not been convincingly demonstrated [
Between 2004 and 2007, a fixed-dose combined formulation containing artesunate (AS) and amodiaquine (AQ) in a single tablet (ASAQ Winthrop) was developed by Sanofi in partnership with the Drugs for Neglected Disease initiative (DNDi) [
This was an open-label Phase IV hypothesis-testing study performed in a single health centre (HC) at Grand Morié in the Agboville district of Côte d’Ivoire. The study was conducted in two parts using an identical design over two distinct enrolment periods separated by an interval of three years, the first from November 2009 to May 2010 and the second from March to October 2013. These two periods corresponded to the beginning and end of a programme of systematic implementation of ACT with ASAQ Winthrop in the health district [
The study was conducted in collaboration with the NMCP of Côte d’Ivoire, the
The study included children (≥5 kg body weight) and adults presenting with proven monospecific infection to
All patients received ASAQ Winthrop using the recommended treatment regimen. ASAQ Winthrop was provided as oral tablets which were to be taken once a day for three days. Administration of the first dose of ASAQ Winthrop was supervised. Tablets could be dissolved in a small amount of water. The dose was adjusted according to the patient’s age using three homothetic dosage strengths (AS 25 mg/AQ 67.5 mg one tablet/day for 2–11 months; AS 50 mg/AQ 135 mg one tablet/day for 1–5 years; AS 100 mg/AQ 270 mg one tablet/day for 6–13 years and two tablets/day for ≥14 years). Compliance was evaluated by counting unused tablets in the packet returned on D3 and by asking the patient.
At the baseline visit, demographic features (age, gender, and weight), past medical history, concomitant medication, and clinical features presented were documented, and a fingerprick blood sample taken for smear tests using a vaccinostyle. At each follow-up visit, a physical examination was performed, clinical signs and symptoms documented, and a fingerprick blood sample taken. Blood samples were taken at Visits D7 and D28 (and at D14 in case of abnormal values on D7) for liver and renal function tests and blood cell count.
Thin and thick blood smears were prepared and stained with a May-Grünwald-Giemsa solution. All slides of blood smears were read by qualified personnel from the Institut Pasteur for Period 1 and from the CeDReS for Period 2 according to standard laboratory procedures. Slides were considered negative if no parasite was detected after reading 200 high-powered fields. The presence and density of gametocytes were also determined.
Blood spots on Whatman 3 M filter paper (four spots per card) were prepared for polymerase chain reaction (PCR) genotyping for all subjects at D0 and at the relevant follow-up visit in the case of treatment failure. Samples were frozen and stored at −20°C before genotyping. Two spots were reserved for molecular genotyping, which was performed centrally at the
Treatment outcomes were classified according to the WHO criteria as adequate clinical and parasitological response (ACPR), early or late clinical failure and early or late parasitological failure at Day 28 confirmed by PCR [
Safety was evaluated through documentation of adverse events (AEs). These were coded using the Medical Dictionary for Regulatory Activities (MedDRA). The investigator asked patients about the occurrence of any adverse event at each study visit. In addition, standard liver and renal function tests and blood cell counts were performed on blood samples taken at D0, D3 (haemoglobin only), D7, D14 (only if anomalies had been observed on D7), and D28. Additional laboratory tests could be performed if required at the investigator’s discretion.
Adverse events of special interest were neutropenia, hepatic dysfunction, and symptoms suggestive of extrapyramidal disorders or retinopathy. Neutropenia was defined as a neutrophil count <400/mm3 for children or <750/mm3 for adults. Hepatic dysfunction was defined as a level of serum alanine aminotransferase (ALAT) >8 × the upper limit or normal (ULN) or >3 × ULN together with total serum bilirubin >2 × ULN.
This study tested the null hypothesis that the ACPR observed during the second study period would be inferior to that observed during the first period. The target sample size was defined a priori in order to evaluate noninferiority with the desired precision. It was hypothesized that noninferiority could be concluded if the difference in ACPR rates between the two study periods did not exceed 5% (i.e., if the lower bound of the 95% confidence interval was superior to a prespecified noninferiority margin of −0.05). Assuming an ACPR rate of around 96%, as observed in previous studies of ASAQ Winthrop elsewhere in Africa [
Three study populations were determined. The safety population consisted of all study patients having received at least one treatment dose. The intent-to-treat (ITT) population consisted of all patients in the safety population who did not reject the first administered dose. The per protocol (PP) population consisted of all patients in the ITT population without major protocol deviations who completed the protocol as planned. The primary analysis was performed in the PP population. All other efficacy analyses were performed in the ITT population and the safety analysis was performed in the safety population.
The study protocol was submitted to the Ethics Committee
Patient disposition across the two periods of the study is illustrated in Figure
Trial profile. Percentages are calculated with respect to the previous line in the flow chart. FU: follow-up; ITT: intention to treat; PP: per protocol.
Patient characteristics at inclusion are presented in Table
Patient characteristics at inclusion.
Period 1 | Period 2 |
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Age (years) | |||
Mean ± SD | 5.35 ± 7.63 | 4.17 ± 4.03 | 0.483 |
Median [range] | 3 [0.4–62.2] | 3.1 [0.3–36.7] | |
Children under five years of age | 201 (69.8%) | 217 (75.9%) | 0.101 |
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Gender | 0.244 | ||
Female | 131 (45.5%) | 144 (50.3%) | |
Male | 157 (54.5%) | 142 (49.7%) | |
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Weight (kg) | 0.639 | ||
Mean ± SD | 16.2 ± 11.7 | 14.8 ± 8.6 | |
Median [range] | 12 [6–71] | 12 [5–63] | |
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Clinical signs and symptoms | |||
Fever1 | 288 (100%) | 286 (100%) | 0.163 |
Asthenia/weakness | 241 (83.7%) | 234 (81.8%) | 0.555 |
Chills | 63 (21.9%) | 122 (42.7%) | <0.001 |
Perspiration | 230 (79.9%) | 225 (78.7%) | 0.725 |
Headache2 | 61/77 (79.2%) | 39/48 (81.3%) | 0.783 |
Pain | 18 (6.3%) | 25 (8.7%) | 0.257 |
Dizziness2 | 5/73 (6.8%) | 7/48 (14.6%) | 0.164 |
Nausea2 | 17/77 (22.1%) | 12/48 (25.0%) | 0.707 |
Decreased appetite/anorexia | 241 (83.7%) | 233 (81.5%) | 0.485 |
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Parasitaemia | |||
Positive thick blood smears1 | 288 (100%) | 286 (100%) | NA |
Mean parasite density (/ |
41.6 ± 45.5 (×103) | 71.1 ± 85.5 (×103) | <0.001 |
Gametocyte carriers | 7 (2.4%) | 5 (1.7%) | 0.568 |
Mean gametocyte density (/ |
47.1 ± 70.9 | 967.8 ± 1290.9 | 0.051 |
Administration of the first treatment dose was supervised. Nonetheless, five patients rejected or vomited their medication at the first intake and a further 44 patients (6.3%; 18 during Period 1 and 26 during Period 2) were not compliant, failing to take all of the planned daily doses.
The primary effectiveness variable was the ACPR rate at D28 in the PP population after PCR correction (Table
Effectiveness: treatment response in the per protocol population.
Period 1 | Period 2 | |
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Adequate clinical and parasitological response (ACPR) | 244 (95.7%) | 231 (96.3%) |
Early clinical failure | None | None |
Early parasitological failure | None | None |
Late clinical failure | 3 (1.2%) | 2 (0.8%) |
Late parasitological failure | None | 1 (0.4%) |
Not assessable | 8 (3.1%) | 6 (2.6%) |
ACPR and parasitological failure were confirmed by PCR. The proportion of patients with ACPR was not significantly different between the two treatment periods (
Adequate clinical and parasitological response (ACPR) rates at Day 28 after PCR correction in the per protocol (PP) and intention-to-treat (ITT) populations. ACPR rates are presented with their 95% confidence limits.
The overall ACPR rate (both periods combined) was 96.0 [95% CI: 93.7–97.5%]. The ACPR rate was similar in children under five (95.0% in Period 1 and 96.1% in Period 2) and in older children and adults (97.3% in Period 1 and 96.7% in Period 2).
Secondary outcome variables in the ITT populations from the two study periods are presented in Table
Secondary effectiveness outcome variables in the ITT population.
Period 1 | Period 2 |
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ACPR rate at D28 after PCR correction | 267 (92.7%) | 259 (90.6%) | 0.385 |
Absence of fever at D3 | 271 (95.4%) | 274 (98.6%) | 0.046 |
Parasite clearance at D3 | 284/2841 (100.0%) | 276/2781 (99.3%) | 0.484 |
Mean time to parasite clearance (days) | 3.0 ± 0.1 | 3.0 ± 0.2 | 0.031 |
Gametocyte carriers at D28 | None | None | — |
Overall, 259 (44.7%) patients experienced at least one AE during the study (Table
Overview of adverse events.
Period 1 | Period 2 |
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Any adverse event | 145 (50.0%) | 114 (39.3%) | 0.010 |
Potentially ASAQ-related adverse events | 14 (4.8%) | 5 (1.7%) | <0.001 |
Serious adverse event | 3 (1.0%) | 2 (0.7%) | 1.000 |
Severe adverse events | 8 (2.8%) | 8 (2.8%) | 1.000 |
Deaths | None | None | — |
Adverse events leading to treatment discontinuation | None | None | — |
Data are presented as the number of patients presenting at least one adverse event.
Six serious AEs were reported in five patients; these were abnormal liver function tests in three patients, which was associated with dysentery in one patient, and anaemia and febrile convulsions, reported in one patient each. Only the cases of abnormal liver function tests were considered as possibly related to the study treatment by the investigator. No deaths and no adverse events leading to treatment discontinuation were reported.
Regarding laboratory safety, no cases of neutropenia (as defined above) were identified. During the first period, three patients were identified with ALAT values >3 × ULN associated with a total serum bilirubin >2 × ULN which were considered as potentially related to treatment. Two of these cases recovered and one was recovering at the end of the study.
The principal objective of the study was to compare the effectiveness of ASAQ Winthrop, as measured by the ACPR, at the beginning and end of a three-year period, over which an extensive programme of ASAQ Winthrop was implemented in the area [
Moreover, the overall ACPR rate (both periods combined) was 96%, which is consistent with those reported from randomised clinical trials [
With regard to safety, no unanticipated adverse events were observed and the incidence of serious adverse events was ≤1%. Three of the six reported serious adverse events related to abnormalities in liver function tests, which are characterised adverse events associated with amodiaquine. No cases of neutropenia, the other principal adverse events of interest, were observed. The incidence and nature of adverse events in this study was comparable to that reported in other randomised clinical trials of ASAQ [
The number of major protocol deviations (85 patients, 14.7% of all enrolments) was relatively high. These corresponded principally to inappropriate treatment administration or to lack of efficacy assessment at D28. The former type of violation probably reflects the fact that treatment administration after the first dose was unsupervised. The second type of violation was higher during the second period than the first and may be related to the frequent public holidays that occurred during the second period, leading to patients travelling away from home to visit friends or relatives.
This study has a number of strengths and limitations. The principal strength relates to the fact that an identical design was used for the two periods of the study, which were performed at the same centre HC by the same investigators. This should ensure comparability of the findings over the three-year period that separated the two study periods. The principal limitation relates to the absence of supervised drug administration; only the first treatment intake was supervised, which means that certain patients may not have respected the recommended dosage regimen, leading to suboptimal elimination of the parasite. Nonetheless, despite unsupervised administration on the second and third treatment days, estimated compliance with treatment was good with 93.8% of patients during the first study period and 90.9% during the second period being fully compliant. Finally, the observation period of the study (28 days) was shorter than that recommended in current WHO guidelines [
High levels of effectiveness and acceptable tolerability were achieved with ASAQ Winthrop fixed-dose combination used for the non-supervised treatment of uncomplicated
S. Duparc is an employee of the Medicines for Malaria Venture. V. Lameyre is employed by the study sponsor, Sanofi. The remaining authors declare that they have no conflicts of interest.