Malaria parasite clearance from patients following artemisinin-based combination therapy in Côte d’Ivoire

Offianan Andre Toure,1 Tiacoh N’Guessan Landry,1 Serge Brice Assi,2,3 Antoinette Amany Kone,1 Eric Adji Gbessi,1 Berenger Aristide Ako,1 Baba Coulibaly,1 Bouakary Kone,4 Oumar Ouattara,4 Sylvain Beourou,1 Alphonsine Koffi,2 Franck Remoue,2,5 Christophe Rogier6 1Malariology Unit, Pasteur Institute of Côte d’Ivoire, Abidjan, Côte d’Ivoire; 2Malaria and Anopheles Research and Management Unit, Pierre Richet Institute, Bouake, Côte d’Ivoire; 3National Malaria Control Program, Bouake, Côte d’Ivoire; 4Department of Medicine, Health Care Center of Dar-Es-Salam, Bouake, Côte d’Ivoire; 5UMR 224-MIVEGEC, Research Development Institute, Montpellier, France; 6Army Health Department, Paris, France Introduction: Parasite clearance is useful to detect artemisinin resistance. The aim of this study was to investigate parasite clearance in patients treated with artesunate + amodiaquine (AS + AQ) and artemether + lumefantrine (AL): the two artemisinin-based combination therapies (ACTs) recommended in the first-line treatment of uncomplicated malaria in Côte d’Ivoire.Methods: This study was conducted in Bouaké, Côte d’Ivoire, from April to June 2016. Patients aged at least 6 months with uncomplicated malaria and treated with AS + AQ or AL were hospitalized for 3 days, and follow-up assessments were performed on days 3, 7, 14, 21, 28, 35, and 42. Blood smears were collected at the time of screening, pre-dose, and 6-hour intervals following the first dose of administration until two consecutive negative smears were recorded, thereafter at day 3 and follow-up visits. Parasite clearance was determined using the Worldwide Antimalarial Resistance Network’s parasite clearance estimator. The primary end points were parasite clearance rate and time.Results: A total of 120 patients (57 in the AS + AQ group and 63 in the AL group) were randomized among 298 patients screened. The median parasite clearance time was 30 hours (IQR, 24–36 hours), for each ACT. The median parasite clearance rate had a slope half-life of 2.36 hours (IQR, 1.85–2.88 hours) and 2.23 hours (IQR, 1.74–2.63 hours) for AS + AQ and AL, respectively. The polymerase chain reaction-corrected adequate clinical and parasitological response was 100% and 98.07% at day 42 for AS + AQ and AL, respectively.Conclusion: Patients treated with AS + AQ and AL had cleared parasites rapidly. ACTs are still efficacious in Bouaké, Côte d’Ivoire, but continued efficacy monitoring of ACTs is needed. Keywords: Plasmodium falciparum, ACTs, parasite clearance, Côte d’Ivoire