Ex vivo activity of the ACT new components pyronaridine and piperaquine in comparison with conventional ACT drugs against isolates of Plasmodium falciparum

Malaria Journal Ex vivo activity of the ACT new components pyronaridine and piperaquine in comparison with conventional ACT drugs against isolates of Plasmodium falciparum Aurlie Pascual 0 7 8 Philippe Parola 6 Franoise Benoit-Vical 13 Fabrice Simon 12 Denis Malvy 11 Stphane Picot 10 Pascal Delaunay 15 Didier Basset 14 Danile Maubon 9 Bernard Faugre 4 Guillaume Mnard 5 Nathalie Bourgeois 2 Claude Oeuvray 3 Eric Didillon 1 Christophe Rogier 0 8 Bruno Pradines 0 7 8 0 Unite de Recherche en Biologie et Epidemiologie Parasitaires Unite de Recherche pour les Maladies Infectieuses et Tropicales Emergentes UMR- 6236, Institut de Recherche Biomedicale des Armees , Allee du Medecin- colonel Jamot,-BP 60109, 13262 Marseille Cedex , France 1 Fulcrum Pharma (Europe) Ltd , Hemel Hempstead , UK 2 Service de Bacteriologie-Virologie-Parasitologie, Centre Hospitalier Universitaire Caremeau , Nimes , France 3 Medicines for Malaria Venture , Geneva , Switzerland 4 Laboratoire de Parasitologie-Mycologie, Centre Hospitalier Universitaire La Timone , Marseille , France 5 Federation des Laboratoires, Hopital d'Instruction des Armees Sainte Anne , Toulon , France 6 Institut Hospitalo-Universitaire en Maladies Infectieuses et Tropicales, Hopital Nord , Marseille , France 7 Centre National de Reference du Paludisme , Marseille , France 8 Unite de Recherche en Biologie et Epidemiologie Parasitaires Unite de Recherche pour les Maladies Infectieuses et Tropicales Emergentes UMR- 6236, Institut de Recherche Biomedicale des Armees , Allee du Medecin- colonel Jamot,-BP 60109, 13262 Marseille Cedex , France 9 Laboratoire de Parasitologie- Mycologie, Centre Hospitalier Universitaire et Universite de Grenoble 1 , Grenoble , France 10 Malaria Research Unit , UMR 5246, CNRS Lyon , France 11 Travel Clinics and Division of Tropical Medicine and Imported Diseases, Centre Hospitalier Universitaire , Bordeaux , France 12 Service de Pathologie Infectieuse et Tropicale, Hopital d'Instruction des Armees Laveran , Marseille, Frnace 13 Laboratoire de Parasitologie-Mycologie, Centre Hospitalier Universitaire de Rangueil , Toulouse , France 14 Laboratoire de Parasitologie-Mycologie, Centre Hospitalier Universitaire Lapeyronnie , Montpellier , France 15 Laboratoire de Parasitologie-Mycologie, Hopital de 1'Archet , Nice , France Background: The aim of the present work was to assess i) ex vivo activity of pyronaridine (PND) and piperaquine (PPQ), as new components of artemisinin-based combination therapy (ACT), to define susceptibility baseline, ii) their activities compared to other partner drugs, namely monodesethylamodiaquine (MDAQ), lumefantrine (LMF), mefloquine (MQ), artesunate (AS) and dihydroartemisinin (DHA) against 181 Plasmodium falciparum isolates from African countries, India and Thailand, and iii) in vitro cross-resistance with other quinoline drugs, chloroquine (CQ) or quinine (QN). Methods: The susceptibility of the 181 P. falciparum isolates to the nine anti-malarial drugs was assessed using the standard 42-hours 3H-hypoxanthine uptake inhibition method. Results: The IC50 values for PND ranged from 0.55 to 80.0 nM (geometric mean = 19.9 nM) and from 11.8 to 217.3 nM for PPQ (geometric mean = 66.8 nM). A significant positive correlation was shown between responses to PPQ and PND responses (rho = 0.46) and between PPQ and MDAQ (rho = 0.30). No significant correlation was shown between PPQ IC50 and responses to other anti-malarial drugs. A significant positive correlation was shown between responses to PND and MDAQ (rho = 0.37), PND and LMF (rho = 0.28), PND and QN (rho = 0.24), PND and AS (rho = 0.19), PND and DHA (rho = 0.18) and PND and CQ (rho = 0.16). All these coefficients of correlation are too low to suggest cross-resistance between PPQ or PND and the other drugs. Conclusions: In this study, the excellent anti-malarial activity of PPQ and PND was confirmed. The absence of cross-resistance with quinolines and artemisinin derivatives is consistent with the efficacy of the combinations of PPQ and DHA or PND and AS in areas where parasites are resistant to conventional anti-malarial drugs. Malaria; Plasmodium falciparum; Anti-malarial; In vitro; Resistance; Pyronaridine; Piperaquine - Background During the past 20 years, many strains of Plasmodium falciparum have become resistant to chloroquine and other anti-malarial drugs [1]. This has prompted a search for an effective alternative anti-malarial drug with minimal side effects. The emergence and spread of parasites resistant to anti-malarial drugs has caused an urgent need for novel compounds to be discovered and developed. One strategy for reducing the prevalence of malaria is the combinatorial use of drugs. The combination protects each drug from the development of resistance and reduces the overall transmission of malaria [2]. The official first-line anti-malarial policy is now artemisinin-based combination therapy (ACT) [3]. The artemisinin derivative causes rapid and effective reduction of the parasite biomass and gametocytes carriage, while the partner drug, which has a longer duration of action, achieves effective clinical and parasitological cure. Different formulations of ACT were evaluated: artesunate-sulphadoxine-pyrimethamine [4], artesunateamodiaquine [5], artemether-lumefantrine [6], artesunate-mefloquine [7], artesunate-chlorproguanil-dapsone [8], dihydroartemisinin-piperaquine [9] and artesunatepyronaridine [10]. However, suspected decreased susceptibility of ACT or, at least, longer parasite clearance times have been described in Cambodia [11-14]. In addition, prior therapy by amodiaquine-containing ACT selected reduced response to monodesethylamodiaquine, suggested that amodiaquine-containing regimens may rapidly lose efficacy in Africa [15]. This emergence of parasite resistance to ACT indicates that novel compounds and combinations need to be discovered and developed. The aim of the present work was to assess i) ex vivo activity of two recent ACT partner drugs, pyronaridine (PND) and piperaquine (PPQ) to define the susceptibility baseline, ii) comparison with standard components of ACT, such as monodesethylamodiaquine (the active metabolite of amodiaquine) (MDAQ), lumefantrine (LMF), mefloquine (MQ), artesunate (AS) or dihydroartemisinin (DHA), and iii) in vitro cross-resistance with other quinoline drugs, such as chloroquine (CQ) and quinine (QN). Methods Plasmodium falciparum isolates In total, 181 P. falciparum isolates were collected between April 2008 and April 2010 from patients hospitalized in France with imported malaria from a malariaendemic country (Angola, Benin, Burkina Faso, Cameroon, Comoros, Congo, Ivory Coast, Gabon, Gambia, Ghana, Guinea, India, Madagascar, Mali, Mozambique, Niger, Central African Republic, Senegal, Thailand, Togo, Zambia). Informed consent was not required for this study as the sampling procedures and testing are part of the French national recommendations for the care and surveillance o (...truncated)