Table 2.

Evaluation of 1a, b, e, 2b, e, 3, and melphalan against a panel of human tumor cell lines^a

Compound	All cell lines		Leukemic cell lines, IC50 (μM)b					SId
	Average GI50 (μM)b	SIc	CCRF-CEM	K562	RPMI-8226	SR	Average
1a	7.94	67.6	0.40	2.19	1.91	0.55	1.26	6.3
1b	>20.4	>30.2	3.31	3.47	—	3.98	3.59	>5.7
1e	>10.2	>269	0.37	1.05	21.4	14.5	9.33	>1.1
2b	4.68	251	0.32	0.33	—	0.63	0.43	10.9
2e	4.57	2512	—	0.49	20.0	—	10.3	0.4
3	>97.7	>2.63	>100	>100	38.0	>100	>84.5	~1.2
Melphalan	26.9	118	6.17	43.7	66.1	1.86	29.5	0.9

^aThe compounds were evaluated against several groups of human tumors including leukemia.

^bThe GI₅₀ and IC₅₀ values refer to the quantities of compounds required to inhibit 50% of the growth of the cells as explained in the text.

^cThe selectivity index (SI) figures are the differences between the highest and lowest GI₅₀ values.

^dThe selectivity index (SI) figures refer to the quotients of the average GI₅₀ value of all the cell lines and the average IC₅₀ figure for leukemic cells.