MGL-3196 is a highly selective thyroid hormone receptor β (THR-β) agonist.
MGL-3196 is 28-fold selective for THR-β (EC50=0.21 μM) over THR-α (EC50=3.74 μM ) in a functional assay. MGL-3196 shows an IC20 of roughly 30 μM for blockage of the hERG channel. The IC50 for CYP3A4/5 and for CYP2C19 is >50 μM, and there is only weak inhibition (roughly 22 μM) of CYP2C9.
MGL-3196 exhibits good exposures and reasonable oral bioavailability in rats. The volume of distribution and clearance are both low. Dose proportional increases in exposure are observed for a suspension of MGL-3196 given orally to DIO mice.In animals treated with MGL-3196 there is a reduction in cholesterol and in liver size, which is secondary to reduction of liver TG. There is no effect on bone mineral density (BMD) or heart or kidney size in MGL-3196 treated animals.