In the case of BRD4 Long , removing a PEG unit from each of the VH032-JQ1 and thalidomide-VH032 (and therefore, thalidomide-JQ1) linkers from 26 to form AB3125 , results in an unfavourable 5.3-fold decrease in degradation, while leading to a much minor ~1.3-fold decrease for the degradation of the other BET proteins (Table ). The shorter linker of 30 however, showed a favourable 4.5-fold decrease in CRBN degradation vs 26, making it also an attractive compound, meeting the criteria for dialling out potential E3 ligase degradation.