LDN-212854 is also known as 5-[6-[4-(1-Piperazinyl)phenyl]pyrazolo[1,5-a]pyrimidin-3-yl]-quinoline. LDN-212854 prevents heterotopic ossification in an inducible mutant ALK2 (activin receptor-like kinase 2).
LDN-212854 is a selective and potent inhibitor of the bone morphogenetic protein (BMP) type I receptor kinases with over 5,000-fold selectivity for BMP versus the closely related TGF-β and activin type I receptors. LDN-212854 has some selectivity for ALK2 with an IC50 of 1.3 nM in preference to other BMP type I receptors, ALK1 (IC50=2.4 nM) and ALK3 (IC50=85.8 nM). LDN-212854 shows better selectivity than LDN193189 in cell-based assays of BMP signaling. LDN-212854 inhibited BMP6-induced osteogenic differentiation, which functions primarily via ALK2, more potently than BMP4, which functions primarily with ALK3 (IC50s of 10 nM versus 40.5 nM), whereas LDN-193189 inhibited both equally. The only off target effects found against a panel of 198 kinases were for RIPK2, ABL1, and PDGFR-β with IC50 values < 100 nM.