PROTAC IRAK4 Degrader-2 (Compound 9) is a PROTAC-based degrader that potently reduces IRAK4 levels, achieving a DC50 of 151 nM in peripheral blood mononuclear cells (PBMCs). It also notably decreases IRAK4 protein levels with a DC50 of 36 nM in the same cell type and inhibits several cytokines in PBMCs [1].