Table 1.

Inhibition of P450 17A1 activities: steady-state IC₅₀ values

Inhibitor	IC50, nM (95% CI limits)a		Predicted Kib (nM)
	Progesterone 17α-hydroxylation	17α-OH pregnenolone lyase	Progesterone 17α-hydroxylation	17α-OH pregnenolone lyase
Abiraterone	3.2 (1.7, 6.2)	4.2 (2.6, 6.9)	1.3	3.4
Orteronel	417 (256, 680)	1060 (810, 1400)	160	870
Seviteronel	3500 (2870, 4250)	3430 (2450, 4810)	1370	2810
Ketoconazole	87 (63, 120)	227 (145, 354)	34	190
Clotrimazole	60 (37, 99)	99 (55, 176)	23	81

^aFrom Figure 3.

^bUsing the relationship IC₅₀ = K_i [1 + (S/K_m)] for competitive inhibition, with K_m values from Ref. (37).