Abstract Details

Title In Vitro Assessment of the Binding and Functional Reponses of Ozanimod and Its Circulating Metabolites Across Human Sphingosine 1-Phosphate Receptors

Topic Multiple Sclerosis

Presentation(s) P6 - Poster Session 6 (12:00 PM-1:00 PM)

Poster/Presentation
Number 9-016

Background Ozanimod is an S1P receptor modulator, which binds with high affinity selectively to S1P receptor subtypes 1 (S1P₁) and 5 (S1P₅), in clinical development for the treatment of relapsing multiple sclerosis. Ozanimod is extensively metabolized in humans to form a number of circulating active metabolites, including 2 major active metabolites CC112273 and CC1084037.

Objective To characterize the binding affinity, functional potency, and relative intrinsic activity of ozanimod and its clinically circulating metabolites across the human sphingosine 1-phosphate (S1P) receptors.

Design/Methods Competitive radioligand binding was performed using tritium-labeled ozanimod to determine if its metabolites compete for the same binding site within S1P₁ and S1P₅. The in vitro pharmacology and selectivity profile of ozanimod and its metabolites was also investigated using GTPγS binding assays in Chinese hamster ovary cell membranes expressing recombinant human S1P_1-5, as well as assessing agonist-mediated S1P₁ and S1P₅ internalization in over-expressing cell lines and intracellular signaling in primary cultures of human astrocytes.

Results Ozanimod and its functionally active metabolites bind to the same orthosteric binding site within S1P₁ and S1P₅. The active metabolites display the same selectivity profile to ozanimod and are agonists for S1P₁ and S1P₅ but inactive at S1P₂, S1P₃, and S1P₄ at clinically relevant concentrations. Agonism at S1P₁ induces receptor internalization whereas S1P₅ does not appear to internalize. Ozanimod and the most predominant metabolite, CC112273, elicit functional intracellular signaling in human astrocytes, and pharmacological characterization performed using more readily available mouse astrocytes determined this to be S1P₁, and not S1P₅ mediated.

Conclusions Ozanimod and its functionally active metabolites bind to the same orthosteric binding site within S1P₁ and S1P₅ and are pharmacologically identical. As such, all circulating metabolites will likely contribute to the observed clinical efficacy in patients with relapsing multiple sclerosis.

Authors/Disclosures
PRESENTER	No disclosure on file
	No disclosure on file
	No disclosure on file
	No disclosure on file
	No disclosure on file
Richard Hargreaves, PhD	No disclosure on file