Pharmacokinetics and pharmacodynamics of a new ACT formulation: Artesunate/Amodiaquine (TRIMALACT) following oral administration in African malaria patients

Abstract

A new fixed-dose combination of artesunate (AS) plus amodiaquine (AQ) (TRIMALACT) was recently developed for the treatment of uncomplicated falciparum malaria. The originality of this combination lies in its galenic formulation which consists of a three-layer tablet with two layers containing each of the active ingredients, i.e. AS and AQ, and these are separated by a middle layer containing an antioxidant compound. To evaluate the efficacy and tolerability of this combination, adults with uncomplicated malaria received three administrations of two tablets (100:300 mg AS/AQ) in a 24-h interval, in Democratic Republic of Congo. Parasitemia and fever were measured and the plasma levels of parent compounds and metabolites [dihydroartemisinin (DHA) and monodesethylamodiaquine (MdAQ)] were determined by high-performance liquid chromatography. In addition, we determined the prevalence of molecular markers of resistance to chloroquine (CQ) and sulfadoxine/pyrimethamine (SP). The AS/AQ combination TRIMALACT demonstrated a good efficacy resulting in an excellent clinical and parasitological response rate of 100% after correction for PCR results. Treatment regimen was well tolerated. The main disposition parameters to AS+AQ were: for DHA, AUC = 632 +/- 475 ng h/ml and Cmax = 432 +/- 325 ng/ml, and for MdAQ = 14268 +/- 4114 ng h/ml and Cmax = 336 +/- 225 ng/ml (mean +/- standard deviation). Parasite genotyping show high frequencies of molecular SP- and CQ-resistance markers with more 80% of the samples showing more than three mutations linked to SP resistance and 93.48% carrying parasite with the CQ-resistant haplotype. This study shows that the AS/AQ combination TRIMALACT is safe and effective in the treatment of highly drug-resistant falciparum malaria.