Animal experiment:

Rats[1]Female Lewis rats are immunized by subcutaneous administration of the inducer at a volume of 0.1 mL into the footpad. Ceralifimod (ONO-4641: 0.01, 0.03 and 0.1 mg/kg), prednisolone (3 mg/kg) or 0.5% MC is administered orally once daily from immunization days 4-21. More specifically, the severity of paralysis is graded on a scoring scale to determine the clinical score. Mouse[1]NOD mice are immunized into the left footpad with the inducer at a volume of 0.05 mL. A second PTX injection is administered 48 h later. Animals that achieve remission after the initial onset are selected and grouped, and Ceralifimod (ONO-4641: 0.01, 0.03 or 0.1 mg/kg) or 0.5% MC is administered orally to each group once daily for 8 weeks. Neurological symptoms are graded according to the degree of paralysis. A clinical score of 5 is assigned to dead animals until the end of observation[1].

Ceralifimod (ONO-4641) is selective, high potent agonist for sphingosine 1-phosphate receptors 1 and 5, with EC50s of 27.3, 334 pM for human S1P receptor 1 and 5, respectively.

Ceralifimod (ONO-4641) has an agonistic action for S1P1 and S1P5, and there is no difference between human and rat in the agonistic action of Ceralifimod (ONO-4641) for S1P1. Ceralifimod (ONO-4641) also induces S1P1 down-regulation in a concentration-dependent manner and by approximately 90% at concentration of 25 nM[1].

The clinical scores of the Ceralifimod (ONO-4641) 0.03 and 0.1 mg/kg groups remain lower than that in the control group. The maximum clinical scores decrease dose-dependently in the Ceralifimod (ONO-4641) groups and those in the Ceralifimod (ONO-4641) 0.03 and 0.1 mg/kg groups are significantly lower than that in the control group. Specifically, paralysis is inhibited completely in seven of eight animals in the Ceralifimod (ONO-4641) 0.1 mg/kg group.In normal NOD mice, the number of peripheral blood lymphocytes is decreased by approximately 20, 60 and 80% at 24 h after a single oral dose of 0.01, 0.03 and 0.1 mg/kg of Ceralifimod (ONO-4641), respectively. In the control group of the NOD mouse model of relapsing-remitting EAE, the relapse rate is 90.0%, and two of the nine animals die. The cumulative clinical score in the control group is 65.4±18.50. In contrast, none of animals in the Ceralifimod (ONO-4641) 0.1 mg/kg group have a relapse; that is, Ceralifimod completely prevents relapse at a dose of 0.1 mg/kg. In the Ceralifimod (ONO-4641) groups, two of the nine animals in the 0.01 mg/kg die[1].

References:
[1]. Komiya T, et al. Efficacy and immunomodulatory actions of ONO-4641, a novel selective agonist for sphingosine 1-phosphate receptors 1 and 5, in preclinical models of multiple sclerosis. Clin Exp Immunol. 2013 Jan;171(1):54-62.