Amodiaquine-Artesunate versus Artemether-Lumefantrine against Uncomplicated Malaria in Children Less Than 14 Years in Ngaoundere, North Cameroon: Efficacy, Safety, and Baseline Drug Resistant Mutations in pfcrt, pfmdr1, and pfdhfr Genes

Abstract

Background. In Cameroon, both Artesunate-amodiaquine (AS/AQ) and artemether-lumefantrine (AL) are used as first-line treatment against uncomplicated malaria in line with the WHO recommendations. We compared the efficacy and safety of both therapeutic combinations and determined the prevalence of drug resistance conferring mutations in three parasite genes. Methods. One hundred and fifty acute malaria patients between six months and 14 years of age were randomized to receive standard doses of either AS/AQ (73) or AL (77) and followedup for 28 days. Outcome of treatment was according to the standard WHO classification. DNA samples from pretreatment parasite isolates were used to determine the prevalence of resistant mutations in the pfcrt, pfmdr1, and dhfr genes. Results. Both drug combinations induced rapid clearance of parasites and malaria symptoms. PCR-corrected cure rates were 100% and 96.4% for AL. The combinations were well tolerated. Major haplotypes included CVIET (71%), CVMNT (25%) for the pfcrt; SND (100%) for the pfmdr1; IRN (79, 8%), NCS (8.8%), and mixed haplotype (11, 8%) for the dhfr. Conclusion. Both AS/AQ and AL were highly effective and well tolerated for the treatment of uncomplicated falciparum malaria in Ngaoundere, Cameroon. High prevalence of mutant pfcrt alleles confirms earlier observations. Long-term monitoring of safety and efficacy and molecular markers is highly solicited.

Figure 1

Kaplan Meier curve of the PCR adjusted efficacy outcome of treatment with either AS/AQ or AL during 28 days of followup. Assessment was per protocol and protocol violations were censored from the survival analysis.

Figure 2

Evolution of febrile patients following ingestion of AS/AQ and AL during 28 days of followup. During the trial period, fever, measured by adjusted axillary temperatures >37.5°C, was estimated daily during the first three days and subsequently during the trial protocol days and any other day the child felt unwell. There was no significant difference in fever clearance between trial groups (P > 0.05).

Figure 3

Evolution of parasite clearance in patients on treatment with AS/AQ or AL during 28 days of followup. Parasite clearance was measured daily for the first three days, and then on every other day including during regular appointments. Parasite load was estimated by microscopy in Giemsa stained thick blood smears. Within the first three days of ingestion of medication, parasite clearance was not different between treatments but was observed to be significantly lower in children on AS/AQ after day 7 (P < 0.001).

Figure 4

(a) and (b) show the prevalence of haplotypes of the dhfr and pfcrt genes in Ngaoundere, a savannah region in the north of Cameroon. IRN represents the fansidar resistance conferring mutant in the dhfr gene, NCS represent the wild type haplotype, and mixed haplotype is also represented. These haplotypes were built based on the presence of absence of mutation in codon 76 of the pfcrt gene (a) or cumulative mutations at codons 51, 59, and 108 of the dhfr gene (b).