MS4078 is an inhibitor and PROTAC (degrader) of ALK. MS4078 reduces the NPM-ALK protein levels in SU-DHL-1 cells and the EML4-ALK protein levels in NCI-H2228 cells with DC50 of 11 nM and 59 nM, respectively. MS4078 induces ALK protein degradation via cereblon and proteasome dependent mechanism and potently inhibits proliferation of SU-DHL-1 cells with IC50 of 33 nM.