Related Articles In vitro sensitivity of Plasmodium falciparum to conventional and novel antimalarial drugs in Papua New Guinea.

Trop Med Int Health. 2010 Jan 11;

Authors: Wong RP, Lautu D, Tavul L, Hackett SL, Siba P, Karunajeewa HA, Ilett KF, Mueller I, Davis TM


Summary Objective Recent clinical studies have shown high rates of malaria treatment failure in endemic areas of Papua New Guinea (PNG), necessitating a change of treatment from chloroquine (CQ) or amodiaquine (AQ) plus sulphadoxine-pyrimethamine to the artemisinin combination therapy (ACT) artemether plus lumefantrine (LM). To facilitate the monitoring of antimalarial drug resistance in this setting, we assessed the in vitro sensitivity of Plasmodium falciparum isolates from Madang Province. Methods A validated colorimetric lactate dehydrogenase assay was used to assess growth inhibition of 64 P. falciparum isolates in the presence of nine conventional or novel antimalarial drugs [CQ, AQ, monodesethyl-amodiaquine (DAQ), piperaquine (PQ), naphthoquine (NQ), mefloquine (MQ), LM, dihydroartemisinin and azithromycin (AZ)]. Results The geometric mean (95% confidence interval) concentration required to inhibit parasite growth by 50% (IC(50)) was 167 (141-197) nm for CQ, and 82% of strains were resistant (threshold 100 nm), consistent with near-fixation of the CQ resistance-associated pfcrt allele in PNG. Except for AZ [8.351 (5.418-12.871) nm], the geometric mean IC(50) for the other drugs was