Table 1.

Best CDKi’s identified in this study for selective target engagement in live cells.

CDK	Compound	On target potencya	Collateral CDK (potency)
CDK2	NU6102	290 nM	STb
CDK3	RO-3306	200 nM	CDK7 (690 nM)
CDK4/6	Palbociclib	10 nM/2 nM	STb
CDK4/6	Ribociclib	29 nM/31 nM	STb
CDK7	THZ1	90 nM	CDK11a (300 nM)
CDK7	BS-181	470 nM	STb
CDK9	BAY-1251152	9 nM	STb
CDK9	Atuveciclib	150 nM	STb
CDK8/19	CCT251545	6 nM/6 nM	STb
CDK8/19	CCT251545 analog	6 nM/10 nM	STb
CDK8/19	BMS-265246	0.7 nM/1.5 nM	CDK3 (10 nM)
CDK8/19	K08361	3 nM/1.4 nM	CDK7 (63 nM)
CDK12	THZ531	770 nM	STb

^aPotency represents the mean of 3 independent experiments. For S.E.M., see Supplementary Data 2 or 3.

^bSub Threshold: no collateral CDKs were detected with potency below the cutoff of 1 µM.