Ozanimod (Zeposia) is not a biologic, it is a conventional “small molecule” drug that belongs to the class of medicines called sphingosine 1-phosphate (S1P) receptor modulators. Ozanimod does modify the immune system but in a different way to biologics which are drugs that have been derived from living organisms and contain components that control the action of other proteins, cellular processes, genes, or modify the immune system.

Ozanimod is an oral prescription medicine that is approved to treat adults with moderately to severely active ulcerative colitis or relapsing forms of multiple sclerosis (MS) such as:

• clinically isolated syndrome,
• relapsing-remitting disease, and
• active secondary progressive disease.

Research has shown that people taking ozanimod for:

• UC reported decreases in rectal bleeding and stool frequency, and were significantly more likely to experience clinical remission, clinical response, and endoscopic improvement compared to placebo
• MS experienced significantly less disease progression, fewer relapses, and less brain atrophy than those who received standard care, with very few side effects.

How does ozanimod work?

Ozanimod binds tightly and specifically to S1P receptors 1 and 5. S1P is a signaling lipid that helps to control many cellular processes including inflammation, the permeability of the blood vessels, cancer growth, and also adaptive immunity (also called acquired immunity), through the modulation of T-cell trafficking, and innate immunity, which is our first line of defense against infectious diseases. Compounds that target S1P receptors have long been of interest by researchers for the treatment of autoimmune diseases.

The first compound of this class discovered, fingolimod, which was approved in 2010 for relapsing forms of MS, is not as specific as ozanimod, and binds to 4 out of 5 of the S1P receptors, and has a high risk of side effects, such as cardiac toxicity, macular edema, and pulmonary toxicity. Ozanimod is a derivative of fingolimod that is more selective to S1P receptors.

By binding to these receptors, ozanimod is thought to block the ability of lymphocytes to escape from lymph nodes, which traps them in the lymph nodes and reduces their numbers in the blood, central nervous system, and in inflamed tissues. Exactly how ozanimod works in UC and MS is not known but is thought to be by a reduction in the migration of lymphocytes into the gut or central nervous system respectively.

How does ozanimod affect the immune system?

Ozanimod affects the immune system by preventing the migration of lymphocytes from the lymph nodes into blood, the gut, the CNS, and inflamed tissues.

• Because ozanimod modulates the function of lymphocytes it can increase the risk of infection. Ozanimod reduces the numbers of lymphocytes in the blood circulation to around 45% of baseline values. Although rare, life-threatening and fatal infections have occurred in patients receiving ozanimod.
• Use of ozanimod with antineoplastic, non-corticosteroid immunosuppressive, or immune-modulating therapies is also expected to increase the risk of immunosuppression, and these treatments may be contraindicated.
• The use of live attenuated vaccines should also be avoided during and for 3 months after treatment with ozanimod. A full course of vaccination for antibody-negative patients with varicella vaccine is recommended before commencing treatment with ozanimod, This should be undertaken at least 4 weeks before ozanimod is initiated.