Table 2.

Inhibition Data (IC₅₀ values) for Cell-based Assays of Diaryl Hydroxylamines with Ring Substitution^a

Compound no.	Structurea	IDO1 (μM)b	IDO2 (μM)	TDO (μM)
Epacadostat (INCB24360)		0.07	18.9	25.2
PF-06840003		0.21	327	378
1	3 -bromo	0.590	11.8	7.15
2	3,5-dichloro	0.870	8.66	5.70
3	3,4-dichloro	1.91	19.5	8.11
4	4,4’-dichloro	1.09	12.5	4.53
5		1.43	36.1	123
6	2,4-dichloro	1.99	7.68	4.82
7	3,5-difluoro	0.357	8.75	3.48
8	4-chloro	7.15	27.8	23.7
9	3-fluoro	0.939	9.99	6.21
10	2-fluoro-3 -trifluoromethyl	0.933	16.8	5.62
11		6.74	20.5	58.7
12	2,4-difluoro	1.21	18.9	6.37
13	2 -fluoro-5 -trifluoromethyl	1.09	8.94	9.02
14	2,3-dichloro	1.87	8.95	4.54
15	4,4’-difluoro	1.68	12.1	5.15
16	2-fluoro	1.26	30.5	3.92
17		14.7	19.3	49.7
18	2-bromo	1.46	12.3	22.5
19	2-chloro	2.48	10.7	21.8
20	2-methoxy	1.11	16.5	48.8
21		3.36	49.9	4.41
22		21.0	40.2	2770
23	2 -methoxy −4 -methyl −4’chloro	1.76	8.77	19.1
24	3,5-bis(trifuoromethyl)	3.35	14.5	77.4
25	4-hydroxy	2.89	12.6	29.8
26	3 -trifluoromethyl	1.73	24.7	13.6

^aIn all structures,n=0 unless otherwise shown.

^bThe IDO1 assay used HeLa cells, the IDO2 assay used mouse Trex cells and the TDO assay used Trex cells. Data is from a single data point except for the most potent compounds, which were done in triplicate and the results averaged.