LY2955303

Biochem/physiol Actions

LY2955303 is a potent and selective RARγ antagonist (Ki = 1.09 nM/RARγ, >1.70 µM/RARα, >2.98 µM/RARβ) that effectively inhibits RARγ-, but not RARα- or RARβ-, dependent reporter activity upon 15 nM all-trans retinoic acid stimulation in respective HEK293 transfectants (KB = 7.11 nM/RARγ, 1.51 µM/RARβ, 4.44 µM/RARα; 10 nM ATRA for RARβ transfectant). LY2955303 exhibits therapeutic efficacy in a rat model of osteoarthritis-like joint pain (ED50 = 0.72 mg/kg; single p.o. dosage 9 days post OA pain induction by MIA intra-articular injection) with good pharmacokinetic properties, aqueous solubility (>1.0 mg/mL in simulated intestinal fluid), oral availability (F = 26%; 10 mg/kg p.o. over 2 mg/kg i.v.), and no RARα antagonism-associated adverse effects (no testicular degeneration up to 10 mg/kg) seen with BMS-189453 treatment or in RARα-knockout mice.