Next, we sought to use the same live cell kinetic degradation assay set up as described above to evaluate degradation potency (Dmax 50) and degradation rate (Rate Constant λ, hr -1 ) of compounds 23 -32 in HiBiT-BRD2, HiBiT-BRD3, and HiBiT-BRD4 HEK293 cell lines. This provides an orthogonal degradation assay to western blot, enables quantification of degradation rate, and allows for comparison with the initial compounds 1 and 2 (Figure , kinetic traces provided in Supplementary Figure ). Reassuringly, the Dmax 50 values ( ). This directly correlates with 27 also having the greatest degradation rate of BRD3 and BRD4, with a λmax of 2.68 h -1 for BRD4, 3.31 h -1 for BRD3 (which was the highest degradation rate of any compound in the series) and 2.37 h 1 for BRD2 (Table & Supplementary Table ).