Section 04 · Monograph
Natalizumab-sztn
Reviewed Nov 2026FDA label
TyrukoAnti-α4 integrin mAb (biosimilar)
- Forms
- IV: 300mg/15mL vial
- Dose
- 300mg IV every 4 weeks (natalizumab biosimilar; REMS for PML risk)
- MOA
- Blocks lymphocyte migration across the blood-brain barrier
Black Box Warning
- Progressive multifocal leukoencephalopathy (PML): risk is higher with anti-JCV antibody positivity, prior immunosuppressant use and treatment longer than 2 years; available only through a restricted REMS program — monitor for any new neurologic signs or symptoms
Indications
- Relapsing forms of multiple sclerosis (monotherapy)FDA-labeled
- Moderately to severely active Crohn's disease in adults with inadequate response to conventional therapy and TNF inhibitorsFDA-labeled
Mechanism of Action
- Humanized monoclonal antibody against alpha-4 integrin that blocks leukocyte adhesion and migration across the blood-brain barrier
Full Dosing
Adult / usual
- 300mg IV infusion over about 1 hour every 4 weeks; observe for 1 hour after each infusion
- FDA-approved biosimilar to Tysabri (Tyruko; US launch November 2025); REMS enrollment required
- Discontinue if no therapeutic benefit in Crohn's disease by 12 weeks
Contraindications
- Current or history of PML
- Hypersensitivity to natalizumab products
Drug Interactions
- Avoid combination with immunosuppressants or TNF inhibitors (PML and infection risk)
- Avoid live vaccines
Adverse Effects
- PML
- Infusion reactions and hypersensitivity, including anaphylaxis
- Hepatotoxicity
- Infections including herpes encephalitis/meningitis
- Thrombocytopenia — discontinue if it occurs
- Headache, fatigue, urinary tract infection, arthralgia
Monitoring Parameters
- Anti-JCV antibody index and MRI surveillance per PML risk
- Liver tests and platelet counts
- Neurologic assessment before each infusion
Pregnancy & Lactation
- Limited human data; hematologic abnormalities reported in exposed infants
- Present in milk