Table 1.

IC50 values for inhibition of CYP17A1-mediated progesterone 17α-hydroxylation and CYP21A2-mediated progesterone 21-hydroxylation by abiraterone and its analogs

entry	Inhibitor	Modification	CYP17A1 IC50 ± S.E. (nM)	CYP21A2 IC50 ± S.E. (nM)	CYP21A2 IC50 CYP17A1 IC50
1	Abiraterone (1b)	–	4.94 ± 0.09	32.4 ± 2.5	6.6
2	Galeterone	–	28.1 ± 2.3	77.2 ± 8.9	2.7
3	3b	17-phenyl	>20,000	≥ 700	–
4	4	Δ4	6.13 ± 0.41	0.70 ± 0.03	0.11
5	6b	5α,6α-epoxide	7.83 ± 0.92	42.1 ± 8.5	5.4
6	7	Δ4, C-6 CN	15.5 ± 2.7	23.9 ± 3.8	1.5
7	8	Δ4, C-6 CONH2	22.8 ± 1.5	673 ± 90	29
8	10b	5α-H, 6α-OH	7.2 ± 0.32	234 ± 32	33
9	12b	5α-H, 6-oxo	12.4 ± 0.49	440 ± 60	35
10	13b	5α-H, 6-oxime	16.5 ± 2.5	1390 ± 120	84
11	14b	B-ring expanded lactam	230 ± 51	3605 ± 1740	16