Natalizumab is a humanized monoclonal antibody targeting α4-integrin, indicated for the treatment of relapsing forms of multiple sclerosis (MS).

How to Use Natalizumab

Standard Administration Regimen

Dose and Frequency: The recommended dose is 300mg, administered as an intravenous infusion once every 4 weeks, with the infusion duration lasting approximately 1 hour.

Dosage Form and Specification: It is supplied as a 15mL sterile concentrate (300mg/vial), which needs to be diluted with 0.9% Sodium Chloride Injection to a volume of 100mL before use.

Infusion Operation Specifications

Dilution Requirement: Withdraw 15mL of the drug solution and add it to 100mL of 0.9% Sodium Chloride Injection. Gently invert to mix; shaking or freezing is avoided.

Stability: The diluted solution can be stored at room temperature for ≤8 hours, or refrigerated (2-8°C) for ≤24 hours. It must be brought to room temperature before use.

Infusion Monitoring: During the infusion and within 1 hour after the end of the infusion, closely monitor for allergic reactions (such as urticaria, hypotension).

Management of Missed Infusions

If a scheduled infusion day is missed, the infusion should be administered as soon as possible, and the original once-every-4-week schedule should be resumed. No dose adjustment is required.

Dose Adjustment of Natalizumab

Dose Adjustment for Immune-Related Adverse Reactions

Allergic Reactions: In case of systemic allergies (such as dyspnea, hypotension), permanent discontinuation of the drug is required.

Infection Risk: Discontinue administration during the period of severe infection (such as pneumonia); after the infection is controlled, evaluate the necessity of restarting treatment.

Abnormal Liver Enzymes: If Grade 3 liver enzyme elevation persists, discontinue administration temporarily; after liver enzymes return to ≤Grade 1, consider dose reduction or permanent discontinuation.

Natalizumab Administration Regimens for Special Populations

Pregnancy and Lactation

Pregnancy: Animal studies have shown risks of fetal thrombocytopenia and anemia (at 7 times the clinical dose). Data in humans are limited. Contraception is required during drug use, and the drug should be used during pregnancy only when the benefits are significant.

Lactation: Whether the drug is excreted into breast milk is unknown. It is recommended to either discontinue the drug or stop breastfeeding.

Pediatric and Geriatric Patients

Pediatric Patients: Efficacy in patients under 18 years of age has not been established, and its use is not recommended.

Geriatric Patients: Clinical study data are insufficient, and individualized evaluation is required.

Hepatic and Renal Impairment

No dose adjustment is required for patients with mild to moderate hepatic or renal impairment; data on patients with severe impairment are lacking.

Immunocompromised Patients

Concomitant use with immunosuppressants (such as azathioprine) is prohibited, as it may increase the risk of progressive multifocal leukoencephalopathy (PML).