Biologic DMARD — Dual IL-17A and IL-17F Inhibitor Pregnancy: Women of childbearing potential should use an effective method of contraception during treatment and for at least 17 weeks after treatment. There is a limited amount of data on use in pregnant women; animal studies do not indicate harmful effects, but as a precautionary measure it is preferable to avoid use during pregnancy. Breast-feeding: it is unknown whether bimekizumab is excreted in human milk and a risk to the newborn/infant cannot be excluded — decide whether to discontinue breast-feeding or the medicine, taking account of the benefit of each.

Bimekizumab

Brand names: Bimzelx

Bimekizumab is a humanised monoclonal antibody biologic used for moderate-to-severe plaque psoriasis, psoriatic arthritis, axial spondyloarthritis and hidradenitis suppurativa.

Auto-extracted from the source labelling — not yet independently clinician-verified. These values were distilled from the UK SPC (or the US label where noted) but have not had a clinician sign-off. Confirm against the current SmPC before prescribing.

Adult dose

Dose: 320 mg (given as 2 subcutaneous injections of 160 mg, or 1 subcutaneous injection of 320 mg)

Route: Subcutaneous injection — suitable sites are the thigh, abdomen and upper arm; rotate injection sites and do not inject into psoriasis plaques or skin that is tender, bruised, erythematous or indurated. Administration in the upper arm may only be performed by a healthcare professional or caregiver. The pre-filled pen must not be shaken.

Frequency: Plaque psoriasis: at week 0, 4, 8, 12, 16 and every 8 weeks thereafter

For use under the guidance and supervision of a physician experienced in the diagnosis and treatment of the licensed conditions. After proper training in subcutaneous injection technique, patients may self-inject with the pre-filled pen if the physician determines it is appropriate, with medical follow-up as necessary. OTHER LICENSED INDICATIONS (adults): PSORIATIC ARTHRITIS — 160 mg (1 subcutaneous injection) every 4 weeks; for psoriatic arthritis patients with coexistent moderate to severe plaque psoriasis the dose is the same as for plaque psoriasis (320 mg at week 0, 4, 8, 12, 16 and every 8 weeks thereafter), and after 16 weeks regular assessment of efficacy is recommended — if a sufficient clinical response in joints cannot be maintained, a switch to 160 mg every 4 weeks can be considered. AXIAL SPONDYLOARTHRITIS (nr-axSpA and AS) — 160 mg (1 subcutaneous injection) every 4 weeks. HIDRADENITIS SUPPURATIVA — 320 mg every 2 weeks up to week 16, then every 4 weeks thereafter. For all the above indications, consideration should be given to discontinuing treatment in patients who have shown no improvement by 16 weeks. OVERWEIGHT PATIENTS WITH PLAQUE PSORIASIS: for some patients with plaque psoriasis (including psoriatic arthritis with coexistent moderate to severe psoriasis) and a body weight of 120 kg or more who did not achieve complete skin clearance at week 16, 320 mg every 4 weeks after week 16 may further improve treatment response. ELDERLY (65 years and over): no dose adjustment required. PAEDIATRIC: safety and efficacy in children and adolescents below the age of 18 years have not yet been established and no data are available — no paediatric dose is stated in the source. PRE-TREATMENT: evaluate patients for tuberculosis before initiating; do not give in active TB; consider anti-TB therapy before initiating in patients with a past history of latent or active TB in whom an adequate course of treatment cannot be confirmed. Bimekizumab is not recommended in patients with inflammatory bowel disease. SOURCE: UK SPC (eMC), Bimzelx 160 mg solution for injection in pre-filled pen, §4.2 — https://www.medicines.org.uk/emc/product/12834/smpc

Dose adjustments

Renal

Bimekizumab has not been studied in patients with renal or hepatic impairment; dose adjustments are not considered necessary based on pharmacokinetics.

Dose auto-extracted from UK Summary of Product Characteristics (SPC) via the eMC; US FDA prescribing information (openFDA / DailyMed) — cross-check; US labelling may differ from UK — not yet clinician-verified. Always confirm against the product SmPC and your local formulary before prescribing.

Contraindications

Hypersensitivity to the active substance or to any of the excipients
Clinically important active infections (e.g. active tuberculosis)

Side effects

Upper respiratory tract infections (very common — 14.5%, 14.6%, 16.3% and 8.8% in plaque psoriasis, psoriatic arthritis, axial spondyloarthritis and hidradenitis suppurativa respectively)
Oral candidiasis (common — 7.3%, 2.3%, 3.7% and 5.6% across the four indications); also oropharyngeal candidiasis, tinea infections, herpes simplex, ear infections, gastroenteritis, folliculitis and vulvovaginal mycotic infection
Headache (common)
Rash, dermatitis and eczema, acne (common)
Injection site reactions (erythema, reaction, oedema, pain, swelling, haematoma) and fatigue (common)
Uncommon: neutropenia, inflammatory bowel disease (new or exacerbations), mucosal and cutaneous candidiasis including oesophageal candidiasis, conjunctivitis. Serious hypersensitivity reactions including anaphylaxis have been observed with IL-17 inhibitors

Interactions

Live vaccines — must not be given to patients treated with bimekizumab; inactivated or non-live vaccinations may be given, and completion of all age-appropriate immunisations should be considered before starting therapy (UK SPC §4.4)
CYP450 substrates with a narrow therapeutic index (e.g. warfarin, ciclosporin) — cytokine modulation during treatment may alter CYP450 enzyme formation; on initiation or discontinuation of bimekizumab consider monitoring effect or drug concentration and consider dosage modification of the substrate (US PI §7; UK SPC §4.5 was not retrieved in this bundle)
Conventional DMARDs including methotrexate — population pharmacokinetic analyses indicated bimekizumab clearance was not affected by concomitant cDMARDs or by prior exposure to biologics (US PI §7)

Clinical monograph

How it works

It selectively inhibits both interleukin-17A and interleukin-17F, cytokines that drive inflammation in psoriatic and spondyloarthritic disease.

Prescribing in practice

It increases susceptibility to infection, including oral candidiasis, and active serious infection (such as tuberculosis) must be excluded and treated before starting.
It is given by subcutaneous injection under specialist rheumatology or dermatology supervision.
It is associated with new onset or exacerbation of inflammatory bowel disease, so caution is needed in those with a history of IBD; live vaccines should be avoided during treatment.

Monitoring

Screen for tuberculosis and active infection before treatment and monitor for signs of infection, candidiasis and inflammatory bowel symptoms during therapy.

Counselling the patient

Report signs of infection, including persistent mouth or throat soreness suggestive of thrush.
Tell the team about any change in bowel habit such as diarrhoea or abdominal pain.
Avoid live vaccines and keep other immunisations up to date before starting where possible.

Evidence & guidelines

Efficacy is demonstrated in phase 3 trials across its indications and supported by NICE technology appraisal guidance.

Reference: BE OPTIMAL Trial (NEJM 2023); BE ACTIVE Trial (Ann Rheum Dis 2023); MHRA Approval Bimzelx 2023; SPC Bimzelx; Drug verified in RxNorm (NLM); confirm dosing against the manufacturer SPC (eMC). Verify against your local formulary and current prescribing references before prescribing. The structured dose values shown have been reviewed by a clinician. Monograph status: clinician-reviewed (2026-07-04).

Curated clinical cross-links plus same-class fallbacks.

Calculators

Pathways