Table 3.

BTK Binding and Target Engagement of BTK and CRBN in HEK293 Cells

Compound	DC50 (nM) Ramos cellsa	BTK Kd (nM)b	BTK IC50 (nM)c	CRBN IC50 (nM)c	Ternary Complex Formationd
GDC-0853		0.35	12.1 ± 1 (1.1)	NDe
Pomalidomide		NDe	NDe	83 ± 10 (0.8)
PTD10	0.5 ± 0.2	2.28	97 ± 11 (1.9)	107 ± 19 (1.0)	100%
PTD13	>3,000	0.86	320 ± 30 (1.4)	7000 ± 700 (1.0)	0
PTD15	113 ± 20	107	3212 ± 208 (1.3)	5000 ± 300 (0.5)	~75%

^aDC₅₀ values are taken from Tables 1 and 2.

^bDetermined by TR-FRET at 37 °C.

^cTarget engagement in cells at 37 °C. Numbers in parentheses are the Hill slopes.

^dMaximum ternary complex formation setting the BRET ratio for PTD10 at 100%.

^eND, not determined.