Natalizumab

TYSABRI

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Pronunciation: na-ta-LIZ-yoo-mab (tye-SA-bree)

Natalizumab ballicule: receptor binding, kinetics and half-life diagram — Mechanism of action: Natalizumab ballicule

What it isAlpha-4 integrin antibody blocking lymphocyte entry into the CNS; relapsing MS and Crohn disease.

Why this oneIt produces rapid, high-efficacy MS control by blocking immune-cell trafficking rather than broadly depleting lymphocytes.

What limits it⚑ Progressive multifocal leukoencephalopathy risk depends on JC virus antibody, prior immunosuppression, and duration; monitoring is mandatory.

Natalizumab molecular structure (skeletal formula) — Molecular structure: Natalizumab

FDA label

Read the full label on DailyMed ↗

BOXED WARNING Progressive multifocal leukoencephalopathy (PML): increased risk of PML, an opportunistic viral brain infection usually leading to death or severe disability; risk factors include anti-JCV antibodies, treatment duration, and prior immunosuppressant use; available only through the TOUCH Prescribing Program (REMS).

FDA dosing	Population	Start	Target	Max
Relapsing forms of multiple sclerosis (monotherapy)	Adults	300 mg IV over 1 hour q4wk	300 mg IV q4wk	300 mg IV q4wk
Moderately to severely active Crohn's disease (inadequate response/intolerance to conventional therapy and TNF-α inhibitors)	Adults	300 mg IV over 1 hour q4wk	300 mg IV q4wk	300 mg IV q4wk

Renal Undefined (pharmacokinetics not studied in renal insufficiency)

Hepatic Undefined (pharmacokinetics not studied in hepatic insufficiency)

Instructions

300 mg IV infusion over ~1 hour every 4 weeks; do not give as IV push or bolus
Dilute in 100 mL 0.9% Sodium Chloride only; administer within 8 hours of preparation (use within 48 h if refrigerated)
Observe during all infusions; observe 1 hour post-infusion for first 12 infusions
In Crohn's disease, do not use with immunosuppressants or TNF-α inhibitors; discontinue if no benefit by 12 weeks

Available strengths

inj 300 mg/15 mL

Contraindications

Patients who have or have had progressive multifocal leukoencephalopathy (PML)

Cautions

PML and JCV granule cell neuronopathy (see Boxed Warning)
Herpes encephalitis, meningitis, and acute retinal necrosis — can be fatal or cause blindness
Hepatotoxicity, including liver failure — discontinue if liver injury
Serious hypersensitivity reactions including anaphylaxis — permanently discontinue
Immunosuppression/increased infection risk
Thrombocytopenia (including ITP); neonatal thrombocytopenia and anemia — obtain CBC in exposed neonates
Immune reconstitution inflammatory syndrome (IRIS)

Adverse reactions

Headache
Fatigue
Arthralgia
Urinary tract infection
Lower respiratory tract infection
Gastroenteritis
Depression
Rash
Nausea (Crohn's)
Upper respiratory tract infection (Crohn's)

Pregnancy No adequate data; neonatal thrombocytopenia and anemia reported with 3rd-trimester exposure (obtain CBC in exposed neonates); animal studies show fetal hematologic/immunologic effects and increased abortions

Lactation Natalizumab detected in human milk; no data on effects on breastfed infant or milk production; weigh benefits vs. risk

Cost

Natalizumab (TYSABRI)

Strength		#/mo	generic $/unit	CostPlus
300 mg/15 mL	inj	per unit		not offered

NADAC is a voluntary CMS survey of what retail community pharmacies pay for the drugs they stock. Natalizumab is administered under clinical supervision and dispensed outside retail pharmacies, so it rarely appears on surveyed invoices.

⚠ BOXED WARNING

Progressive multifocal leukoencephalopathy

Classes and tags

Clinical profile

Therapeutic safety burden4 / 4

Overdose danger1 / 4

Weight-gain liability1 / 4

Sedation liability1 / 4

QT / Torsades0 / 4

Direct muscarinic antagonism0 / 4

Embryofetal risk3 / 4

Defining liabilityProgressive multifocal leukoencephalopathy with death or severe disability

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