Natalizumab is a recombinant humanized IgG4κ monoclonal antibody. As a crucial drug in the field of multiple sclerosis (MS) treatment, its unique α4-integrin inhibitory effect provides patients with a new treatment option.

How Effective is Natalizumab in Treatment?

Clinical Efficacy Performance

Natalizumab specifically binds to α4β1 and α4β7 integrins, blocking the adhesion of leukocytes to vascular endothelial cells, thereby inhibiting the migration of inflammatory cells to the central nervous system.

In clinical trials, this drug significantly reduced the clinical relapse rate in patients with relapsing multiple sclerosis and increased the proportion of patients without relapses.

Magnetic Resonance Imaging (MRI) assessments showed that the drug effectively reduced the number of new or enlarged T2 hyperintense lesions and gadolinium-enhancing lesions.

Combined Therapy Characteristics

When natalizumab is used in combination with interferon beta-1a, it can still maintain its therapeutic effect. Although the drug clearance rate is somewhat reduced, the profile of adverse events is similar to that of monotherapy.

Indicated Populations for Natalizumab

Main Indicated Population

Natalizumab is indicated for the treatment of patients with relapsing multiple sclerosis to reduce the frequency of clinical deterioration.

Precautions for Special Populations

The efficacy of natalizumab in pediatric patients with multiple sclerosis under 18 years of age has not been studied, and it is not recommended for use in pediatric patients.

There is insufficient data on the use of natalizumab in elderly patients (over 65 years of age), so careful evaluation should be conducted.

Natalizumab is classified as a Category C drug for use during pregnancy. Animal studies have shown that high doses may cause changes such as fetal thrombocytopenia, and human data are limited. Its use during pregnancy requires a careful weighing of the benefits and risks.

The efficacy of natalizumab in lactating women is unknown, and consideration should be given to discontinuing the drug or stopping breastfeeding.

Medication Monitoring for Natalizumab

Key Points of Laboratory Monitoring

Treatment with natalizumab leads to an increase in the number of circulating lymphocytes, monocytes, eosinophils, basophils, and nucleated red blood cells.

This effect persists during the medication period but usually returns to baseline levels within 16 weeks after drug discontinuation.

The number of neutrophils is not affected. Routine laboratory monitoring should include a complete blood count and liver function tests.

Adverse Reaction Monitoring

Special vigilance should be paid to infusion reactions (incidence rate of approximately 22%) and hypersensitivity reactions (including severe systemic reactions such as anaphylaxis, with an incidence rate of <1%). These reactions mostly occur within 2 hours after the start of infusion.

Other adverse events requiring monitoring include infections (especially pneumonia), depression (including suicidal ideation), and cholelithiasis.

In case of severe hypersensitivity reactions, the drug should be discontinued immediately and must not be used again.

Enhanced monitoring is required for patients with persistent positive anti-drug antibodies (accounting for approximately 6%). Such patients are more likely to experience infusion-related reactions, and the therapeutic effect of the drug is significantly reduced.

Antibody testing should be performed regularly during treatment (e.g., once every 12 weeks), and patients with persistent positive antibodies should be considered for adjustment of the treatment regimen.