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Acta Tropica 102 (2007) 176–181
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Efficacy of artesunate plus amodiaquine, artesunate plus sulfadoxine-pyrimethamine, and chloroquine plus sulfadoxine-pyrimethamine in patients with uncomplicated Plasmodium falciparum in the Comoros Union Adama Tall a,b , L´eon P. Rabarijaona b , Vincent Robert a,c , Said Ahmed Bedja d , Fr´ed´eric Ariey a,e , Milijaona Randrianarivelojosia a,∗ a
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Unit´e de recherche sur le paludisme, Institut Pasteur de Madagascar, B.P. 1274 Antananarivo (101), Madagascar b Institut Pasteur de Dakar, B.P. 220 Dakar, Senegal c IRD, MNHN, USM-504 biologie fonctionnelle des protozoaires, B.P. 52, 61 rue Buffon, 75231 Paris cedex 05, France d Direction g´ en´erale de la sant´e, Moroni, Comoros Unit´e d’´epid´emiologie mol´eculaire, Institut Pasteur du Cambodge, B.P. 983, 5 boulevard Monivong, Phnom Penh, Cambodia
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Received 25 March 2007; accepted 25 March 2007 Available online 3 May 2007
Abstract
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Health policy makers in Comoros Union have considered a policy change recommending combination treatment to control malaria. We evaluated the efficacy of three antimalarial drug combinations, taken orally, to enable the authorities to make an evidence-based choice. The study was carried out in patients of 2–70 years old in Moroni, Moheli and Anjouan in 2003. We enrolled 168 patients with uncomplicated malaria from 1097 outpatients screened at the health centres. One hundred and fifty-eight patients, of whom half were under five years old, (mean age = 11.1 ± 13.9 years), were followed up for 14 days. According to PCR adjusted outcome, the therapeutic efficacy of artesunate + amodiaquine (AS + AQ) (n = 54) and artesunate + sulfadoxine-pyrimethamine (AS + SP) (n = 53) was 100%, whereas that of chloroquine + sulfadoxine-pyrimethamine (CQ + SP) was 98% (50/51). The key difference between these treatments was the higher parasite clearance rate on Day 2 obtained with artesunate-containing combinations (P < 0.001). These results provide a baseline for monitoring changes in the susceptibility of Plasmodium falciparum to artesunate + amodiaquine and artesunate + sulfadoxine-pyrimethamine (ACTs) in the Comoros Union. Health policy changes involving the replacement of chloroquine in the Indian Ocean subregion are discussed. © 2007 Elsevier B.V. All rights reserved. Keywords: Malaria; Comoros Union; ACT; Artesunate; Amodiaquine; Drug policy
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1. Introduction
Malaria remains the leading cause of hospital admissions and deaths in the Comoros Union where malaria
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Corresponding author. Fax: +261 20 22 415 34. E-mail address:
[email protected] (M. Randrianarivelojosia).
0001-706X/$ – see front matter © 2007 Elsevier B.V. All rights reserved. doi:10.1016/j.actatropica.2007.03.004
is controlled mostly by the use of insecticide-treated bed nets and antimalarial drugs (Blanchy and Benthein, 1989; Ouledi, 1995; Randrianarivelojosia et al., 2004a). Malaria transmission is perennial and the Anopheles gambiae complex is present in the three islands of the Comoro Archipelago (Petrarca et al., 1990). In 2004, 55,577 clinical malaria cases were reported in Grande Comore, of which 17,734 were microscopically
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positive-RDT were randomised to treatment groups if they met most of the following criteria: resident in the Comoros Union, at least six months old, fever in the last 24 h or axillary temperature ≥37.5 ◦ C, no evidence of concomitant febrile illness, more than 10 kg (body weight), informed consent given, no history of treatment with antifolate or amodiaquine in the previous week, not pregnant, no danger signs or evidence of severe malaria. 2.2. Treatments
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We tested three combination treatments: artesunate + amodiaquine (AS + AQ), artesunate + sulfadoxinepyrimethamine (AS + SP) and chloroquine + sulfadoxine-pyrimethamine (CQ + SP). At each study site, the first patient enrolled following the diagnosis of malaria by RDT was treated with AS + AQ, the second was treated with AS + SP and the third with CQ + SP. This process was repeated until the end of the enrolment period. A clinician prescribed the drugs and supervised the administration of all doses. Febrile patients were given paracetamol at enrolment. Doses of antimalarial drugs and paracetamol were established according to WHO guidelines (WHO, 2001). All patients were given the full antimalarial treatment assigned, but we assessed the therapeutic efficacy of the antimalarial drugs studied exclusively in patients with monospecific P. falciparum infection, confirmed by microscopy, and a parasite density of 1000–200,000 l of blood.
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confirmed (Bedja, personal communication). The Comorian national policy has recommended chloroquine monotherapy as the first-line treatment for the last few decades with sulfadoxine-pyrimethamine as the second line treatment. Currently, the prevalence of chloroquine-resistant Plasmodium falciparum strains is high (Ariey et al., 2002; Randrianarivelojosia et al., 2004a). In 2001, a 14-day follow-up study demonstrated the failure of standard chloroquine treatment in 76.6% of children under the age of 10 years. Genotyping studies revealed the presence of the pfmdr1 N86Y mutation in all P. falciparum isolates examined, together with a mutation at position 76 in pfcrt (83.3%) (Randrianarivelojosia et al., 2004a). On the basis of the 14-day follow-up in 2005, accurate clinical and parasitological responses to sulfadoxine-pyrimethamine (SP) ranged between 90 and 100% in patients of all ages in Comoros (Silai, personal communication). However, mutant pfdhfr 108N P. falciparum isolates occurred at high frequency (Randrianarivelojosia et al., 2004a). Comorian health policy makers therefore planned to change the official policy concerning the management of uncomplicated malaria, recommending a change from chloroquine monotherapy to combination therapy. In 2003, prior to the policy change, we evaluated the therapeutic efficacy of artesunate + amodiaquine (AS + AQ), and artesunate + sulfadoxinepyrimethamine (AS + SP), and chloroquine + sulfadoxine-pyrimethamine (CQ + SP) to enable the authorities to make an evidence-based choice.
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2.3. Post-treatment follow-up
2.1. Study site and patients
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2. Patients and methods
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The Institut Pasteur de Madagascar medical team was mobilised within the framework of regional surveillance of drug resistant malaria initiated in 2001 (Ariey et al., 2002; Randrianarivelojosia et al., 2004a, 2004b; Tall et al., 2004). This study was carried out from March 22nd to May 9th 2003 on the three islands of the Comoros Union—Anjouan, Moheli and Grande Comore—according to the WHO protocol (WHO, 2002). Consecutive patients attending primary health care centres with symptoms suggestive of malaria were referred to the study physicians. Malaria was initially diagnosed by rapid diagnostic tests (RDT), using the dipstick available in the Comoros Union at the time of the study (Makromed® , Makro Medical Pty. Ltd., Johannesburg, South Africa), which detects the circulating parasite HRP2 antigen. Blood smears were prepared, stained and examined the following day. Patients with
We used a 14-day follow-up period for this study, as used to assess the efficacy of chloroquine monotherapy in the Comoros Union in 2001 (Randrianarivelojosia et al., 2004a) and the efficacy of artemether + lumefantrine in Mayotte in 2002 (Tall et al., 2004). The main endpoints were the clinical and parasitological (asexual form) responses. Patients who gave informed consent for participation were asked to return to the health centre on Days 1, 2, 3, 7 and 14 and on any other day on which they felt unwell. Clinical examinations were carried out at each visit. Signs and symptoms were recorded on a standard form. In cases of treatment failure, patients were treated with artemether + lumefantrine. All patients failing to attend the health centre were traced by field staff. 2.4. Laboratory procedures Blood smears were stained with 10% Giemsa stain for 15 min. Parasite densities were determined from thick blood smears, by counting the number of asexual para-
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out in Mayotte in 2002 (Tall et al., 2004). This protocol was also approved, in its entirety, by the Comoros Union Health Authorities. Informed consent for participation was obtained from patients or their guardians. Each of the included patients completed a standardised questionnaire and underwent a basic clinical examination.
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3. Data analysis
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Case report forms were reviewed daily and data were analysed with EpiInfo 6.04 (CDC, Atlanta, Georgia, USA). We carried out per-protocol analysis of efficacy data to optimise our estimation of treatment outcome. With the exception of patients violating the study protocol by taking other antimalarial drugs before D3, few patients did not complete the follow-up period. Therapeutic responses were categorised as early treatment failure, late clinical failure, late parasitological failure and adequate clinical and parasitological response (WHO, 2002). Pair-wise comparisons of treatment efficacy were made, using chi-squared or Fisher’s exact tests and continuous variables were compared by t-tests for independent samples. We considered p-values below 0.05 to be statistically significant.
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sites per 200 white blood cells (WBCs) or per 500 WBCs, if there were less than 10 parasites/200 WBCs, assuming a WBC count of 8000 l. Blood smears were prepared for parasite counts on Days 0, 1, 2, 3, 7 and 14. Stained thick blood smears were examined microscopically by an experienced microscopist. All thick blood film readings were standardised and quality control checks were carried out (Tall et al., 2004). Haemoglobinaemia and glycaemia were evaluated on Day 0 respectively, by use of HemoCue B-Hemoglobin photometer (HemoCue Ltd, Sheffield, UK) and of glucose meter One Touch Basic (LifeScan, Milpitas, CA, USA). Molecular genotyping techniques were used to distinguish recrudescence from new infections for all patients in whom treatment failed after D3. Blood samples were collected on filter paper on the day of enrolment and on the day on which treatment failure was recorded. Parasite DNA was extracted by methanol–chloroform method (Randrianarivelojosia et al., 2004a). Alleles of the polymorphic loci pfmsp1 and pfmsp2 were compared between pre- and post-treatment parasite isolates (Ranford-Cartwright et al., 1993). If the fragments amplified by PCR differed between preand post-treatment isolates, the patient was considered to have a new infection. If the bands obtained for the two isolates were identical, the patient was considered to present with a recrudescence.
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2.5. Ethical considerations
Preliminary analysis showed no significant difference between the three sites, so the results for all three sites were pooled for the analysis. The study is summarised in Fig. 1 and the patients’ characteristics are reported in Table 1. In total, 459 of the 1097 outpatients seen
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We used the protocol approved by the comit´e consultatif de protection des personnes dans la recherche biom´edicale de Bordeaux, France, for the study carried
4. Results
Fig. 1. Study profile. Therapeutic responses were adjusted on the basis of PCR results.
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Table 1 Baseline characteristics (Day 0) of patients completing the study Treatment group Chloroquine + sulfadoxinepyrimethamine (n = 51) (%)
29 (53.7) 24 (44.4) 5 37.7 (1.13) 6945 (26266) 10.6 (2.5) 1.04 (0.4) 2 (3.7)
22 (41.5) 24 (45.3) 6 37.6 (1.06) 4788 (22764) 10.8 (2.3) 1.06 (0.3) 0
23 (45.1) 21 (41.2) 6 37.6 (1.10) 6358 (23949) 10.5 (1.9) 1.01 (0.2) 1 (2)
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asitaemia of 3000 l. The day after admission, she presented with a febrile syndrome (temperature 38.5 ◦ C) and disorientation. No parasites were detected on any of the slides. The patient was admitted to Moheli reference hospital, where she was treated with antibiotics and intravenous quinine. Repeated thick blood films confirmed the absence of malaria. Additional tests revealed marked uraemia and careful questioning revealed that the patient had been in poor health for the last three months. Renal failure was diagnosed and the patient died during the night of March 31st. This death was probably not related to the administration of antimalarial drugs. However, particular attention will be paid to this case in the context of pharmacovigilance. No early treatment failure or late clinical failure was recorded for any patient on any treatment. Approximately half (51.3%) of the 158 patients completing the 14-day follow-up period were children under the age of five years. PCR adjusted outcome indicated a thera-
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at the health centres were screened for malaria. RDTs were positive in 326 (71%) patients. In microscopy, among the 326 RDT-positive patients, seven slides were negative; one case of P. falciparum + P. malaria and one case of P. falciparum + P. vivax were detected; and 317 were P. falciparum malaria (149 with parasitaemia
