Table 1. In vitro inhibitory effects of MY-24 and ribavirin against arenaviruses^a.

			MY-24c			Ribavirin c
Virus	Assay b	CC50 ± SD	EC50/90 ± SD	SI d	CC50 ± SD	EC50/90 ± SD	SI d
TCRV	CPER	28±8.2	0.9±0.2	31	1106±356	12±2.5	92
	VYR		0.9±0.2	31		8.2±2.0	135
JUNV	CPER	33±5.7	2.4±1.2	14	1188±356	11±5.7	108
	VYR		1.1±0.6	30		10±3.9	119
PICV	CPER	28±15	16±10	2	1024±217	16±8.2	64
	VYR		2.4±1.2	12		7.8±2.5	132

^aData are the mean and standard deviations from 3 separate experiments in Vero (JUNV and PICV) or Vero 76 (TCRV) cells.

^bCytopathic effect reduction (CPER) based on neutral red dye uptake by viable cells; virus yield reduction (VYR).

^cCC₅₀ and EC₅₀ values are inµM.

^dSelectivity index (SI)  =  CC₅₀/EC_50/90.