natalizumab
Tysabri · ATC code L04AG03
- Key facts
- Active substance
- natalizumab
- Drug class
- Immunosuppressive drug
- ATC code
- L04AG03
- Authorisation
- centrally authorised across the EU (EMA)
- Dosage forms
- Tysabri 300 mg concentrate for solution for infusion · Tysabri 150 mg solution for injection in pre-filled syringe
- Marketing authorisation holder
- Biogen Netherlands B.V.
- Information as of
- 2026-10-27
Key facts
Natalizumab (Tysabri) is a monoclonal antibody. It is used as single disease-modifying therapy in adults with highly active relapsing remitting multiple sclerosis.
What it is used for
- Highly active RRMS despite a full and adequate course of at least one disease-modifying therapy
- Rapidly evolving severe RRMS (2 or more disabling relapses in one year with gadolinium-enhancing lesions or a significant increase in T2 lesion load)
Dosing
- Tysabri 300 mg concentrate: 300 mg intravenous infusion every 4 weeks over approximately 1 hour, then 1 hour of observation
- Tysabri 150 mg pre-filled syringe: 300 mg subcutaneously every 4 weeks (two syringes)
- Reconsider if no benefit beyond 6 months; reassess benefit and risk after 2 years
- Switch of administration route 4 weeks after the previous dose
- Not recommended over 65 years; not established in children and adolescents
Contraindications
- Hypersensitivity to the active substance or any excipient
- Progressive multifocal leukoencephalopathy (PML)
- Increased risk for opportunistic infections, including immunocompromised patients
- Combination with other disease-modifying therapies
- Known active malignancies, except cutaneous basal cell carcinoma
Important warnings
- Increased risk of PML (caused by JC virus), which may be fatal or cause severe disability
- PML risk factors: anti-JCV antibodies, treatment duration especially beyond 2 years, prior immunosuppressant use
- JCV granule cell neuronopathy has been reported
- Hypersensitivity reactions; provide the Patient Card and re-inform patients about risks
Side effects
- Most frequent: headache (32%), nasopharyngitis (27%), fatigue (23%), urinary tract infection (16%), nausea (15%), arthralgia (14%), dizziness (11%)
- Subcutaneous use: also injection site pain (4%)
- Serious: PML, opportunistic infections, hypersensitivity reactions
Interactions
- Contraindicated with other disease-modifying therapies
- Live vaccines have not been studied
Pregnancy and breastfeeding
- If pregnancy occurs, consider discontinuation, weighing the possible return of disease activity
- Data from trials and a pregnancy registry do not suggest an effect on pregnancy outcomes
Summary of the official product information, written with AI (Claude, Anthropic) on 2026-10-28. Every number was checked automatically against the original text. Not reviewed by a physician – the full official text is authoritative.
Common questions – ask Medelix
For patients
Package leaflet, verbatim
Authorisation and brand names by country
Medicines with exactly this active-substance composition, as listed in the national registers – alphabetical and without ranking. Whether a product is currently available is not shown here.
EU – centrally authorised (all member states)
Source: European Medicines Agency (EMA), product information
Turkey
- TysabriGEN İLAÇ VE SAĞLIK ÜRÜNLERİ SAN. VE TİC. A.Ş., BIOGEN TURKEY İLAÇ TİCARET LİMİTED ŞİRKETİ · 2 register entries
Source: TİTCK – Ruhsatlı Beşeri Tıbbi Ürünler Listesi, as of 2026-10-16
Brand names in 3 more European countries
- Iceland
- Tyruko, Tysabri
- Liechtenstein
- Tyruko, Tysabri
- Norway
- Tyruko, Tysabri
EMA – Article 57 product data (EU/EEA), 2026-10-28
Medelix receives no money from pharmaceutical companies. Brand names are listed alphabetically and without ranking.
Other substances in the same group
Another question about this substance?
Medelix answers clinical questions from guidelines, studies and product information – every claim with its source.
Sources
- European Medicines Agency. Tysabri – EPAR, Product Information (OF THE TEXT Detailed information on this medicinal product i). 2026-10-27. https://www.ema.europa.eu/en/documents/product-information/tysabri-epar-product-information_en.pdf
- TİTCK – Ruhsatlı Beşeri Tıbbi Ürünler Listesi, 2026-10-16. https://www.titck.gov.tr/dinamikmodul/85
- Wikidata (CC0): ATC L04AG.
Editorial: Medelix editorial team · last updated 2026-10-27 · How these pages are made · Report an error
Source: European Medicines Agency (EMA), product information. Not advertising, not a treatment recommendation. For questions about your own treatment, ask your doctor or pharmacist.