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

How Effective is Natalizumab?

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 (CNS).

In clinical trials, this medication significantly reduced the rate of clinical relapses in patients with relapsing forms of multiple sclerosis (RMS) and increased the proportion of patients with no relapses.

Magnetic Resonance Imaging (MRI) assessments showed that Natalizumab effectively reduced the number of newly emerging or enlarging T2 hyperintense lesions and gadolinium-enhancing lesions.

Combined Treatment Characteristics

When Natalizumab is used in combination with interferon beta-1a, it still maintains its therapeutic efficacy. Although the drug clearance rate is slightly reduced, the profile of adverse events is similar to that of monotherapy.

Indicated Populations for Natalizumab

Main Target Population

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

Precautions for Special Populations

Pediatric patients under 18 years old: The efficacy of Natalizumab in children with multiple sclerosis has not been studied, and it is not recommended for pediatric use.

Elderly patients (over 65 years old): Data on the use of Natalizumab in this population are insufficient, so careful evaluation is required.

Pregnancy: Natalizumab is classified as a Category C medication for pregnancy. Animal studies have shown that high doses may cause changes such as fetal thrombocytopenia; human data are limited, and its use requires weighing the risks and benefits.

Lactating women: The efficacy of Natalizumab in lactating women is unknown. Consider discontinuing the medication or ceasing breastfeeding.

Medication Monitoring for Natalizumab

Key Laboratory Monitoring Points

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

This effect persists during treatment but typically returns to baseline levels within 16 weeks after discontinuing the medication.

Neutrophil counts are not affected. Routine laboratory monitoring should include complete blood count (CBC) and liver function tests.

Adverse Reaction Monitoring

Special vigilance is required for infusion reactions (incidence rate approximately 22%) and hypersensitivity reactions (including severe systemic reactions such as anaphylaxis, incidence rate < 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 medication should be discontinued immediately and must not be used again.

Enhanced monitoring is needed for patients with persistent positive anti-drug antibodies (accounting for approximately 6%). These patients are more prone to infusion-related reactions, and the drug’s efficacy is significantly reduced.

Antibody testing should be performed regularly during treatment (e.g., once every 12 weeks). For patients with persistent positive results, consideration should be given to adjusting the treatment regimen.