PLX647 dihydrochloride is a potent and selective dual inhibitor of FMS and KIT kinases, with IC50 values of 28 nM and 16 nM, respectively. At a concentration of 1 μM, PLX647 dihydrochloride demonstrates superior selectivity against a wide range of 400 kinases, except FLT3 and KDR, where IC50 values are 91 nM and 130 nM, respectively. This orally active compound holds great potential for targeted kinase inhibition.

In vitro, PLX647 dihydrochloride potently inhibits proliferation of BCR-FMS cells, with an IC 50 of 92 nM. A corresponding Ba/F3 cell line expressing BCR-KIT is also quite sensitive to PLX647 dihydrochloride, with an IC 50 of 180 nM. PLX647 dihydrochloride also inhibits endogenous FMS and KIT, as demonstrated by inhibition of the ligand-dependent cell lines M-NFS-60 (IC 50 =380 nM) and M-07e (IC 50 =230 nM), which express FMS and KIT, respectively[1]. PLX647 dihydrochloride potently inhibits the growth of FLT3-ITD-expressing MV4-11 cells (IC 50 =110 nM). PLX647 dihydrochloride displays minimal inhibition of the proliferation of Ba/F3 cells expressing BCR-KDR (IC 50 =5 μM). PLX647 dihydrochloride inhibits osteoclast differentiation with an IC 50 of 0.17 μM[1].

PLX647 dihydrochloride (40 mg/kg; p.o.; twice daily for 7 days) reduces macrophage accumulation in UUO kidney and blood monocytes[1]. PLX647 dihydrochloride (40 mg/kg; p.o.; male Swiss Webster mice) reduces LPS-induced TNF-α and IL-6 release[1]. PLX647 dihydrochloride (20-80 mg/kg; p.o.; daily or twice daily from 27-41 days) shows effects on collagen-induced arthritis[1]. PLX647 dihydrochloride (30 mg/kg) results in significant inhibition of TRAP5b immunostaining and bone osteolysis. PLX647 dihydrochloride (30 mg/kg BID) is able to prevent bone damage by the tumor cells[1]. Animal Model: Male C57BL/6 mice (mouse unilateral ureter obstruction model)[1]Dosage: 40 mg/kg Administration: P.o.; twice daily for 7 days Result: Resulted in reduction in the levels of F4/80+ macrophages by 77%. Animal Model: 7-9 wk old Male DBA/1J mice (Mouse collagen-induced arthritis model)[1]Dosage: 20 mg/kg, 80 mg/kg Administration: P.o.; daily (20 mg/kg) from 27-41 days, twice daily (80 mg/kg) from 27-41 days Result: 20 mg/kg PLX647 had no initial effect on the development of severe arthritis. However, starting on day 33, no further development of disease severity was recorded, and a 30% inhibition of the macroscopic signs of arthritis was evident in clinical score on day 41. Mice treated with 80 mg/kg BID PLX647 initially shows delayed development of severe arthritic signs. Starting on day 33, the signs of arthritis began to decrease in this treatment group, reaching a maximum reversal of 76% on day 41.