ofatumumab: clinical use

Prescribing considerations

• Initiation and supervision should involve a clinician experienced in neurological disease.
• Assess immune status, active infection, vaccination requirements and previous immune-modifying treatment before initiation.
• Screen all patients for hepatitis B surface antigen and core antibody; involve a liver specialist when serology is positive.
• Record the product name and batch number for biological-medicine traceability.
• Consider potential fetal or neonatal B-cell depletion when planning pregnancy and infant vaccination.

Contraindications and cautions

• Hypersensitivity to ofatumumab or an excipient
• Severely immunocompromised state
• Severe active infection until resolved
• Known active malignancy

Monitoring

• Monitor clinically for infection and injection or hypersensitivity reactions.
• Remain vigilant for clinical or MRI features suggestive of progressive multifocal leukoencephalopathy; suspend treatment while this is investigated.
• Review immunoglobulins where clinically indicated, particularly with recurrent infection, because IgM may decrease.
• For positive hepatitis B serology, arrange specialist monitoring and preventive management.

Clinical pharmacology

A fully human IgG1 anti-CD20 antibody that depletes CD20-positive B cells primarily by complement-dependent cytotoxicity and, to a lesser extent, antibody-dependent cellular cytotoxicity. Following subcutaneous administration, it is absorbed mainly through the lymphatic system and degraded as a protein into peptides and amino acids.

Formulation and product differences

• The selected product is a clear to slightly opalescent solution in a single-use pre-filled auto-injector pen for subcutaneous administration.
• Keep refrigerated and protected from light; do not freeze. It may be kept outside refrigeration once for up to 7 days at no more than 30°C and, if unused, returned to refrigeration for up to a further 7 days.

Injection

Route: Parenteral

Strengths: 20 mg