Filgotinib

How it works

It preferentially inhibits JAK1, modulating the JAK-STAT signalling of multiple pro-inflammatory cytokines involved in immune-mediated inflammation.

Prescribing in practice

• As a JAK inhibitor it carries class risks of serious infection, venous thromboembolism, major cardiovascular events and malignancy, so MHRA advice restricts use in those over a certain age, smokers and patients with cardiovascular or cancer risk factors.
• Screen for tuberculosis, hepatitis and other infections before starting, and avoid live vaccines during treatment.
• Use under specialist supervision with dose adjustment in renal impairment, and caution given a potential effect on fertility under evaluation.

Monitoring

Monitor full blood count, lipids, liver function and for signs of infection or thromboembolism during treatment.

Counselling the patient

• Report signs of infection, chest pain, breathlessness or a swollen, painful leg promptly.
• Do not have live vaccines without discussing them with your team.
• Attend monitoring blood tests and report any new lumps or unexplained symptoms.

Evidence & guidelines

MHRA safety advice on JAK inhibitors and NICE technology appraisal guidance inform the cautious use of filgotinib in inflammatory arthritis and ulcerative colitis.