efgartigimod alfa: clinical use

Prescribing considerations

• Initiate and supervise treatment through a clinician experienced in neuromuscular disorders.
• Review active infection and vaccination status before and during treatment.
• The subcutaneous formulation may be suitable for trained patient or caregiver administration after required supervised initiation.
• Record the product name and batch number for biological-medicine traceability.
• Review concurrent immunoglobulin, Fc-containing biological therapies and plasma-removal procedures.
• Clinical evidence is very limited in moderate or severe renal impairment; paediatric safety and efficacy are not established.

Contraindications and cautions

• Hypersensitivity to efgartigimod alfa or any formulation excipient.
• Use caution with active or serious infection and previous hypersensitivity reactions.
• Efgartigimod alfa has not been studied as treatment for myasthenic crisis and must not delay established emergency management.

Monitoring

• Monitor for clinical evidence of infection and reconsider administration during active or serious infection.
• Observe for infusion, injection and hypersensitivity reactions according to the formulation-specific SmPC.
• Monitor disease control closely when reducing or stopping corticosteroids, non-steroidal immunosuppressants or anticholinesterase therapy.
• Assess whether concurrent Fc-containing therapies retain their intended clinical effect.
• Review suspected adverse reactions and report through the Yellow Card scheme.

Clinical pharmacology

Efgartigimod alfa binds FcRn with increased affinity, reducing recycling and increasing lysosomal clearance of circulating IgG, including pathogenic autoantibodies. It is expected to be broken down into small peptides and amino acids.

Formulation and product differences

• The intravenous product is a concentrate requiring dilution and healthcare-professional administration; it is licensed for AChR-antibody-positive generalised myasthenia gravis.
• The pre-filled syringe is a ready-to-use subcutaneous formulation licensed for eligible adults with generalised myasthenia gravis or CIDP and may support trained home administration.
• The subcutaneous formulation commonly causes local injection-site reactions; infusion-related headache is specific to intravenous administration.
• The formulations have different excipients and sodium content, which may matter for people with relevant allergies or sodium restrictions.

Solution for infusion

Route: Intravenous

Strengths: 20 mg/mL

Injection

Route: Parenteral

Strengths: 1000 mg