Tysabri®

Overview

Tysabri® is the brand name for natalizumab, a monoclonal antibody therapy used in the treatment of multiple sclerosis (MS). It is a disease-modifying therapy designed to reduce inflammatory disease activity in relapsing forms of MS. Biologically, natalizumab acts by interfering with immune-cell trafficking, thereby limiting the migration of leukocytes into the central nervous system and helping to reduce relapse-related inflammatory damage.

Clinically, Tysabri® is used in settings where high-efficacy treatment is needed, and it is commonly discussed alongside other advanced MS therapies such as ocrelizumab. Recent research has also examined alternative formulations and delivery routes, including transition from intravenous to subcutaneous natalizumab, as well as biosimilar use, reflecting ongoing interest in treatment convenience, pharmacokinetics, safety, and real-world effectiveness.

Recent Publications Focus

Below is a summary of the newest research publications targeting Tysabri® (sorted by publication date).

• 2026-06-22 — Serum biomarkers remain stable after transitioning from intravenous to subcutaneous natalizumab in multiple sclerosis.
  This study examined whether switching from intravenous to subcutaneous natalizumab affects serum biomarker stability in people with MS. The authors noted that subcutaneous natalizumab may offer greater convenience than intravenous administration, but that pharmacokinetic differences had raised concerns about possible subclinical disease activity. The reported focus was on serum biomarkers, and the study concluded that these biomarkers remained stable after the route transition, supporting the idea that the subcutaneous formulation preserves biological stability in the setting of ongoing natalizumab treatment.

• 2026-06-21 — Natalizumab is associated with improved relapse outcomes and lower healthcare utilization versus ocrelizumab in treatment-naïve people with multiple sclerosis.
  This real-world comparative study evaluated natalizumab against ocrelizumab in treatment-naïve people with MS. The publication framed both therapies as well-established options commonly considered first-line in newly diagnosed patients in the United States. The reported findings indicated that natalizumab was associated with improved relapse outcomes and lower healthcare utilization relative to ocrelizumab in this cohort, highlighting its effectiveness in routine clinical practice.

• 2026-06-11 — Brain Immune Cell Composition in Multiple Sclerosis and Progressive Multifocal Leukoencephalopathy After Natalizumab: An Immunohistochemical Cohort Study.
  This immunohistochemical cohort study investigated brain immune-cell composition in MS and in PML after natalizumab exposure. The publication explicitly linked natalizumab therapy with increased PML risk and with potential changes in lymphocyte distribution within the CNS. The study context suggests an emphasis on tissue-level immune profiling, including immune-cell populations such as T helper cell and human cytotoxic t cell subsets, to better understand how natalizumab may reshape CNS immune architecture in both MS and PML.

• 2026-06-01 — Real-world transition from uncontrolled disease to stability: Three-year Pre-post natalizumab comparison in relapsing multiple sclerosis.
  This real-world pre-post study compared disease activity before and after natalizumab initiation in the same patients with relapsing MS over three years. The authors described natalizumab as a highly effective therapy for relapsing MS and noted that relatively few real-world studies had directly assessed within-patient changes after treatment start. The study’s central conclusion was that patients transitioned from uncontrolled disease to stability after natalizumab treatment, supporting its role in reducing relapse activity in routine practice.

• 2026-06-01 — Validation of a new diagnostic ELISA to detect anti-JCV antibodies in serum of patients with multiple sclerosis considering or receiving treatment with natalizumab.
  This diagnostic validation study focused on a new ELISA-based assay for detecting anti-JCV antibodies in serum from patients with MS who were considering or receiving natalizumab. The assay used the ImmunoWELL JCV enzyme-linked immunosorbent assay and was aimed at improving JCV serologic assessment in the natalizumab-treated population. The work is directly relevant to natalizumab safety monitoring because JCV antibody status is central to PML risk stratification.

• 2026-05-01 — Safety and patient experiences with the natalizumab biosimilar in multiple sclerosis treatment.
  This real-world study assessed patient experiences and natalizumab serum concentrations after switching from the originator, Tysabri®, to a natalizumab biosimilar. The publication focused on safety and treatment experience in routine MS care, indicating that the biosimilar switch was evaluated in terms of tolerability and drug exposure. The study contributes to the growing evidence base on biosimilar use in natalizumab-treated patients and suggests that serum concentration monitoring can be informative during such transitions.

• 2026-04-30 — Differential safety profiles of disease-modifying therapies in MS: Age- and sex-based analysis from a real-world cohort.
  This real-world cohort study compared adverse event patterns across several MS disease-modifying therapies, including dimethyl fumarate, fingolimod, natalizumab, and ocrelizumab. The analysis specifically assessed age- and sex-specific adverse event profiles within each treatment cohort. In this context, natalizumab was evaluated as part of a broader safety comparison, contributing to understanding of how patient demographics may influence therapy-associated adverse events in MS care.

Method PMIDs

• [PMID 42107470]

Target PMIDs

• [PMID 42275616]
• [PMID 42332277]
• [PMID 42323726]
• [PMID 41985260]
• [PMID 42134893]
• [PMID 41861706]