Table 2.

Anti-HIV-1 and HIV-2 activity (EC₅₀) in human T-lymphocyte CEM cells.

Compd	Nucleoside	AA	R	EC50 (μM)		CC50 (μM)
				HIV-1	HIV-2
2	d4T	–	–	0.39 ± 0.29	0.58 ± 0.33	≥250
16	d4T	l-Ala	Bn	0.14 ± 0.028	0.096 ± 0.063	92 ± 0
17	d4T	l-Ala	cHex	0.15 ± 0.16	0.38 ± 0.42	73 ± 9
18	d4T	l-Ala	CH2tBu	0.090 ± 0.084	0.14 ± 0.042	96 ± 3
3	ddA	–	–	7.2 ± 2.5	2.8 ± 1.8	>250
19	ddA	l-Ala	CH2tBu	0.10 ± 0.069	0.049 ± 0.028	35 ± 5.0
4	AZT	–	–	0.012 ± 0.006	0.067 ± 0.018	>250
20	AZT	l-Ala	Bn	0.0092 ± 0.00035	0.030 ± 0.0092	30 ± 4
21	AZT	l-Ala	CH2tBu	0.0083 ± 0.00014	0.013 ± 0.0042	75 ± 40
5	3TC	–	–	0.099 ± 0.086	0.18 ± 0.13	>250
22a	3TC	l-Ala	Bn	16 ± 5.3	58 ± 44	>250
23b	3TC	l-Ala	Bn	0.28 ± 0.17	0.40 ± 0.33	214 ± 60
25	3TC	l-Ala	Bn	>50	>50	116 ± 9
11	ABC	–	–	23 ± 5.0	18 ± 8.9	>250
34	ABC	l-Ala	Bn	0.56 ± 0.23	1.1 ± 0.82	19 ± 0
35	ABC	l-Ala	CH2tBu	1.5 ± 0.47	1.2 ± 0.66	27 ± 2
10	ACV	–	–	>250c	–	>250c
32	ACV	l-Ala	Bn	2.01 ± 1.16c	–	34.93 ± 1.45c
33	ACV	l-Ala	CH2tBu	4.07 ± 1.06c	–	82.76 ± 4.54c

Data represent the mean ± SD of at least 2 to 3 independent experiments.

^aPhosphorotetraamidate.

^bN-Phosphorodiamidate.

^cMT-4 cell.