NIBR-0213

Biological Activity

NIBR-0213 is an orally active, potent and S1P1-selective sphingosine 1-phosphate (S1P) receptor antagonist that blocks S1P1-selective ligand AUY954-induced Ca²⁺ mobilization (IC50 = 2.5 nM using human S1P1-transfected HeLa cells; IC50 >10 μM with human S1P2, S1P3, or S1P4 transfectants) and S1P-induced GTPγS recruitment (IC50 = 2.0/2.3/8.5 nM using membrane from human/murine/rat S1P1-transfected CHO cells; IC50 >10 μM with membrane from human S1P5 transfectant). NIBR-0213 induces long-lasting peripheral blood lymphocyte reduction in rats (EDmax = 1 mg/kg, ED50 = 0.2 mg/kg; p.o.) and exhibits therapeutic efficacy (30 mg/kg p.o; BID) in experimental autoimmune encephalomyelitis (EAE), a murine model of multiple sclerosis (MS), with no adverse effects to the animals.

Conversion of different model animals based on BSA (Value based on data from FDA Draft Guidelines)

Species	Mouse	Rat	Rabbit	Guinea pig	Hamster	Dog
Weight (kg)	0.02	0.15	1.8	0.4	0.08	10
Body Surface Area (m2)	0.007	0.025	0.15	0.05	0.02	0.5
Km factor	3	6	12	8	5	20

Animal A (mg/kg) = Animal B (mg/kg) multiplied by	Animal B Km
	Animal A Km

For example, to modify the dose of Compound A used for a mouse (20 mg/kg) to a dose based on the BSA for a rat, multiply 20 mg/kg by the K_m factor for a mouse and then divide by the K_m factor for a rat. This calculation results in a rat equivalent dose for Compound A of 10 mg/kg.

Chemical Information