natalizumab at a glance
Medicine class
Humanised anti-α4-integrin monoclonal antibody.
Main use
Highly active relapsing-remitting multiple sclerosis in adults.
Administration
Given by intravenous infusion or subcutaneous injection, depending on the selected product.
Key safety issue
Progressive multifocal leukoencephalopathy (PML), a rare but potentially fatal brain infection associated with JC virus.
What is natalizumab used for?
The selected products are licensed as single disease-modifying therapy for adults with highly active relapsing-remitting multiple sclerosis.
Highly active disease despite an adequate course of at least one other disease-modifying therapy.
Rapidly evolving severe relapsing-remitting multiple sclerosis meeting the clinical and MRI criteria in the product licence.
How does natalizumab work?
Natalizumab binds α4-integrins on most white blood cells. This blocks adhesion signals needed for these cells to cross blood-vessel walls into inflamed nervous tissue, reducing immune-cell recruitment and inflammatory lesion activity in multiple sclerosis.
natalizumab preparations and strengths
Solution for infusion
Route: Intravenous
Strengths: 300 mg
Injection
Route: Parenteral
Strengths: 150 mg
How to take natalizumab
Treatment is started and supervised by a specialist multiple-sclerosis team with access to MRI. Intravenous treatment is diluted and given by infusion; the pre-filled syringe product is injected under the skin. Suitable established patients may use subcutaneous treatment outside a clinic or self-inject after specialist approval, supervised training and review of the safety checklist. Food does not affect either route.
Carry and read the Patient Card supplied by the treatment team.
For subcutaneous treatment, use only the injection sites and technique taught by the healthcare professional.
Do not inject if the pre-administration checklist identifies possible PML, infection or allergy symptoms; contact the specialist team.
Do not stop or change formulation without discussing it with the specialist team.
natalizumab side effects
Common or expected effects
- Headache or dizziness
- Tiredness
- Nausea
- Joint pain
- Cold-like nose and throat symptoms
- Urinary tract infection
- Injection- or infusion-related reactions such as chills, flushing, itching or rash
Get urgent medical advice
- PML or other JC-virus neurological disease
- Severe allergic reaction or anaphylaxis
- Herpes infection affecting the brain, meninges or retina
- Serious opportunistic infection
- Liver injury
- Low platelets, including immune thrombocytopenia, causing bleeding or bruising
natalizumab in pregnancy
Natalizumab may be used during pregnancy when recommended by a specialist after balancing control of multiple sclerosis against treatment risks. Available evidence has not shown a specific pattern of birth defects, but information remains limited. Later-pregnancy exposure may affect the baby's blood cells or immune system, so neonatal blood tests and the timing of live vaccines require specialist planning. Do not stop treatment without discussing the risk of renewed disease activity.
natalizumab while breastfeeding
Natalizumab passes into human milk, and its effect on a breastfed infant is uncertain. The selected product information advises discontinuing breastfeeding during treatment; discuss feeding and multiple-sclerosis management with the neurology, maternity and paediatric teams before birth or before restarting treatment.
natalizumab interactions
Give the specialist team a complete list of medicines, biological treatments and planned vaccines.
Other multiple-sclerosis disease-modifying therapies
Concurrent use is contraindicated because combined immune effects may increase serious infection risk.
Immunosuppressive or antineoplastic medicines
Current or previous treatment may increase opportunistic-infection and PML risk; immune status and treatment timing require specialist assessment.
Common questions about natalizumab
Answers are fully visible for fast scanning and source review.
Can natalizumab cure multiple sclerosis?
No. It reduces inflammatory disease activity and future nerve damage risk but does not cure multiple sclerosis or reverse all established damage.
What does a positive JCV antibody test mean during natalizumab treatment?
It means previous exposure to JC virus and a higher PML risk than a negative result. It does not mean that PML is present; the antibody index and other risk factors guide monitoring and treatment discussions.
Sources
These sources were used to prepare and review this medicine page.
Prepared and reviewed by the iatroX editorial team.