Etrasimod

How it works

It selectively modulates S1P receptor subtypes, causing retention of lymphocytes in lymphoid tissue and so reducing the circulating lymphocytes available to infiltrate the inflamed colon.

Prescribing in practice

• Before starting, assess cardiac status, ophthalmic and infection risk because S1P modulators can cause bradycardia and atrioventricular conduction delay at initiation, macular oedema, and increased risk of infection.
• Check full blood count, liver function and varicella zoster immunity, and ensure vaccinations are up to date before treatment, avoiding live vaccines during and for a period after therapy.
• It is contraindicated in pregnancy and effective contraception is required, as S1P modulators are associated with a risk of fetal harm.

Monitoring

Monitor for signs of infection, perform liver function tests, and arrange ophthalmic assessment in patients at higher risk of macular oedema, with cardiac monitoring as advised at initiation.

Counselling the patient

• Use reliable contraception throughout treatment and tell your doctor if you might be pregnant.
• Report any visual disturbance, signs of infection or breathlessness.
• Keep your vaccinations up to date and avoid live vaccines.

Evidence & guidelines

Its efficacy in ulcerative colitis is supported by randomised placebo-controlled trials and it has been appraised for NHS use by NICE.