TABLE 2.

In vitro susceptibility to standard antimalarial drugs of the initial P. falciparum isolate from 2014 versus P. falciparum W2 clone tested with the same plate batch

Drug	IC50a		Resistance cutoff
	2014 Isolate	W2 clone (SD)
Piperaquine (nM)	174	53.8 (9.0)	135
Dihydroartemisinin (nM)	6.3	2.6 (0.6)	10.5
Artesunate (nM)	2.7	1.5 (0.3)	10.5
Chloroquine (nM)	126	483 (30)	100
Quinine (nM)	434	388 (30)	800
Monodesethylamodiaquine (nM)	38.4	92 (16)	80
Lumefantrine (nM)	18.6	0.93 (0.39)	150
Pyronaridine (nM)	24.8	21.0 (2.8)	60
Mefloquine (nM)	90.9	25.5 (3.2)	30
Doxycycline (μM)	37.0	11.3 (2.1)	35

^aIC₅₀s of W2 are means of 7 independent experiments. Threshold values for reduced in vitro susceptibility or resistance were estimated previously (5, 20).