Table 4.

Effect of combinations of 3TC and NNRTIs on HIV-1 breakthrough in CEM cell cultures

Compound	Concentration, μg/ml	Mean day of HIV-1 breakthrough (50% cytopathicity)
		3TC concentration, μg/ml
		0	0.02	0.05	0.1
BHAP U-90152	0.02	6	27	34	47
	0.04	8	29	64	>52*
TSAO-m3T	0.1	6	19	34	>52†
	0.4	13	23	>52†	>52*
MKC-442	0.02	15	33	>52*	>52*
	0.04	15	50	>52*	>52*
UC-10	0.05	6	33	>52†	>52*
	0.2	21	42	>52*	>52*
None		3	4	6	13

^*The cell culture remained p24 negative, even after removal of the drugs at day 52 post infection, and continued cultivation of the cells in the absence of the test compounds for an additional 12 subcultivations. 

^†When the drugs were washed out at day 52 post infection and the cell cultures were further passaged in the absence of the test compounds, virus breakthrough (50% cytopathicity) occurred on day 57 (for TSAO-m³T) and day 66 (for UC-10).