Anti-IgE Monoclonal Antibody Pregnancy: Avoid unless clearly needed — insufficient data

Omalizumab

Brand names: Xolair

Adult dose

Dose: 75–600 mg SC every 2–4 weeks (dose and frequency based on serum IgE and body weight — use Xolair dosing table)

Route: Subcutaneous injection

Frequency: Every 2 or 4 weeks

Max: 600 mg per dose

For severe persistent allergic asthma inadequately controlled despite step 4 therapy. Check IgE levels (30–1500 IU/mL) and weight to determine dose. Administer by healthcare professional. 15–30 min observation post-injection for anaphylaxis.

Paediatric dose

Route: SC

Frequency: Every 2 or 4 weeks

Max: As per dosing table

Concentration: 150 mg/mL mg/ml

Licensed ≥6 years for severe allergic asthma. Same dosing table by weight and IgE.

Dose adjustments

Renal

No formal dose adjustment required

Hepatic

No formal dose adjustment required

Clinical pearls

Responders (≥20% reduction in severe exacerbations at 16 weeks) should continue; review annually
NICE TA278: recommended add-on for adults and children ≥6 with severe allergic asthma and inadequate control on step 4
Anaphylaxis can occur up to 4 days post-injection — prescribe adrenaline auto-injector for patients
Also approved for chronic spontaneous urticaria and nasal polyps

Contraindications

Total IgE <30 or >1500 IU/mL
Non-allergic asthma (IgE not elevated)
Active helminth infection

Side effects

Injection site reactions
Anaphylaxis (rare, 0.1%)
Headache
Sinusitis
Fever
Arthralgia

Interactions

Minimal systemic interactions — monoclonal antibody
Live vaccines — avoid concomitant use (theoretical)

Monitoring

IgE levels at baseline (for dosing)
Peak flow/spirometry
Exacerbation frequency
Anaphylaxis symptoms for 30 min post-injection

Reference: BNFc; BNF; NICE TA278; GINA 2024; Xolair SPC. Verify against your local formulary and the latest BNF before prescribing.

Curated clinical cross-links plus same-class fallbacks.

Calculators

Drugs

Pathways