Malaria Parasite Clearance from Patients Following Artemisinin-based Combination Therapy in Côte D'Ivoire

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.