TABLE 3

Summary of IC₅₀ values for 17α-hydroxypregnenolone 17,20-lyase inhibition (targeted reaction), progesterone and pregnenolone hydroxylation (off-target reactions), and resulting selectivity ratios

The IC₅₀ values are the average of two independent experiments ± S.E. Within each experiment, each inhibitor concentration was evaluated in duplicate or triplicate.

Inhibitor	Lyase IC₅₀	Progesterone Hydroxylase IC₅₀	Progesterone Hydroxylase IC₅₀ Lyase IC₅₀	Pregnenolone Hydroxylase IC₅₀	Pregnenolone Hydroxylase IC₅₀ Lyase IC₅₀
	nM	nM		nM
Abiraterone	36 ± 2	76 ± 5	2.1 ± 0.2	121 ± 7	3.3 ± 0.3
Galeterone	100 ± 10	130 ± 10	1.3 ± 0.2	150 ± 20	1.5 ± 0.3
(S)-orteronel	210 ± 20	950 ± 70	4.5 ± 0.5	700 ± 100	3.3 ± 0.6
(R)-orteronel	460 ± 90	4000 ± 300	8 ± 2	5000 ± 1000	11 ± 3
(S)-seviteronel	430 ± 40	1170 ± 90	2.7 ± 0.3	700 ± 100	2.1 ± 0.4
(R)-seviteronel	5000 ± 1000	11,300 ± 900	2.3 ± 0.5	N/D	N/D

N/D, not determined.