Natalizumab (brand name: TYSABRI®) is a humanized monoclonal antibody primarily used in the treatment of specific neurological disorders. Based on the content of the FDA label, this article systematically organizes information from three dimensions: indications, pharmacological mechanisms, and patient management, providing a reference for clinical use.

I. What Diseases Does Natalizumab Treat?

1. Core Indications

Natalizumab is approved for the treatment of relapsing forms of multiple sclerosis (MS), which can significantly reduce the frequency of clinical relapses.

2. Usage Restrictions

(1) It is not suitable for chronic progressive multiple sclerosis.

(2) Data on the safety and efficacy in children and adolescents under 18 years of age are insufficient.

II. Pharmacological Mechanism of Action

1. Target Action

As an α4-integrin inhibitor, it specifically blocks the binding of α4β1 and α4β7 integrins to ligands such as VCAM-1 and MadCAM-1.

2. Pharmacodynamic Characteristics

(1) Increases the number of circulating lymphocytes, monocytes, and other (non-neutrophil) cells, which return to baseline levels 16 weeks after drug discontinuation.

(2) The steady-state plasma concentration is approximately 30 mcg/mL, with a half-life of 11 ± 4 days.

(3) Combined use with interferon beta-1a may reduce the clearance rate by 30%, but no dose adjustment is required.

III. Recommendations for Patient Health Management

1. Monitoring During Treatment

(1) Observe for 1 hour after infusion to be alert for hypersensitivity reactions (incidence < 1%).

(2) Monitor liver function and complete blood count every 3 months, and pay attention to changes in lymphocyte count.

(3) Antibody screening: 6% of patients develop persistent antibodies, leading to decreased efficacy.

2. Lifestyle Adjustments

(1) Infection prevention: Avoid contact with sources of infection, and seek medical attention promptly if fever or infection symptoms occur.

(2) Vaccination: It is recommended to complete routine immunization before treatment and avoid the use of live vaccines.

(3) Pregnancy management: Use reliable contraception during medication, and if pregnancy is detected, the necessity of discontinuing the drug should be evaluated.

3. Daily Precautions

(1) Record adverse reactions after infusion (such as headache, joint pain, etc.).

(2) Avoid concurrent use of other immunosuppressants.

(3) Female patients should pay attention to changes in the menstrual cycle (7% report menstrual disorders).