Biologic DMARD — IL-23 Inhibitor (Anti-p19) Pregnancy: Avoid — insufficient human data; animal studies showed no teratogenicity

Guselkumab

Brand names: Tremfya

Adult dose

Dose: 100 mg subcutaneous injection

Route: Subcutaneous

Frequency: Week 0, week 4, then every 8 weeks

Max: 100 mg every 8 weeks

No methotrexate co-administration required. Allow prefilled syringe to reach room temperature for 30 minutes before injection. Used for active psoriatic arthritis and plaque psoriasis.

Paediatric dose

Route:

Not licensed for paediatric use — seek specialist opinion

Dose adjustments

Renal

No dose adjustment required

Hepatic

No dose adjustment required

Clinical pearls

DISCOVER-1 and DISCOVER-2 trials: guselkumab demonstrated significant improvements in ACR20, ACR50, ACR70, and skin outcomes in psoriatic arthritis — DISCOVER-2 included biologic-naive patients only
IL-23 pathway selectivity: guselkumab targets the p19 subunit of IL-23 (shared with IL-39) — more specific than ustekinumab (which targets the p40 subunit shared by both IL-12 and IL-23)
Fungal infections: the IL-17/IL-23 axis is critical for mucocutaneous candidiasis and tinea defence — monitor for oral candidiasis and tinea; counsel patients
NICE TA596: approved for active psoriatic arthritis in adults after inadequate response to DMARDs
Once-every-8-weeks dosing (after initial loading) is an advantage for patient convenience versus biweekly biologics

Contraindications

Active serious infection including TB
Clinically significant hypersensitivity to guselkumab
Live vaccines

Side effects

Upper respiratory tract infections (most common)
Tinea infections — IL-23 pathway important for fungal immunity
Headache
Injection site reactions
Arthralgia
Diarrhoea

Interactions

Live vaccines — contraindicated
Other immunosuppressants — limited data; use with caution
CYP450 substrates: IL-23 inhibition may alter CYP activity; monitor warfarin and ciclosporin levels

Monitoring

Signs of infection
TB testing before initiation
Fungal infection surveillance
Clinical response at 24 weeks

Reference: BNFc; BNF 90; NICE TA596; DISCOVER-1 Trial (Ann Rheum Dis 2020); DISCOVER-2 Trial (Lancet 2020); SPC Tremfya. Verify against your local formulary and the latest BNF before prescribing.

Curated clinical cross-links plus same-class fallbacks.

Calculators

Drugs

Risankizumab (Rheumatology) · Biologic DMARD — IL-23 Inhibitor (Anti-p19)

Pathways