Mcl-1 inhibitor 6 is a potent, orally active chemical compound that selectively inhibits the myeloid cell leukemia 1 (Mcl-1) protein, with a high affinity (K d = 0.23 nM) and binding activity (K i = 0.02 μM). This compound exhibits exceptional selectivity over other members of the Bcl-2 family, including Bcl-2, Bcl2A1, Bcl-xL, and Bcl-w (K d >10 μM). Notably, Mcl-1 inhibitor 6 demonstrates strong antitumor activity.

PROTAC Mcl1 degrader-1 induces the ubiquitination and proteasomal degradation of Mcl-1 by introducing the E3 ligase cereblon (CRBN)-binding ligand pomalidomide to Mcl-1 inhibitor S1-6 with μM-range affinity. PROTAC Mcl1 degrader-1, a proteolysis targeting chimera (PROTAC), is a potently and selectively Mcl-1 inhibitor with an IC50 of 0.78 μM.