Box plots of mean IC50s (in nM) ± standard errors of the means of CQ alone or in combination with VER, PRM, BG920, BG932, BG958, and BG996 at two subinhibitory concentrations without detectable antiplasmodial activity, corresponding to 1/5 and 1/20 of their intrinsic IC50, against CQS and CQR isolates of P. falciparum.