How Tysabri (natalizumab) treats MS
Tysabri treats multiple sclerosis by targeting immune cells involved in inflammation in the central nervous system. It is a monoclonal antibody that blocks the interaction between immune-cell receptors and adhesion molecules on blood-vessel walls, which helps prevent certain inflammatory white blood cells from crossing into the brain and spinal cord. By reducing that immune-cell trafficking, Tysabri helps lower the frequency of relapses and reduces formation of new MS lesions. [1]
What “type” of MS is Tysabri used for?
Tysabri is used for relapsing forms of MS. It is intended for people whose disease has active inflammatory activity (such as relapses), rather than for progressive MS that is not mainly driven by relapses. [1]
What patients usually notice: relapses and MRI activity
Clinically, the main goal is to reduce relapses. A related goal is to reduce new or enlarging lesions seen on MRI, reflecting reduced inflammatory activity that would otherwise drive attacks and injury over time. [1]
What is the treatment mechanism, step by step?
Tysabri works at the point where immune cells would normally move from the bloodstream into the nervous system. By blocking that “entry” step, it reduces the immune attack on myelin and other tissue in the CNS, which is a driver of MS relapses and inflammatory lesions. [1]
Risks and why doctors monitor patients closely
The immune-blocking effect that helps Tysabri control MS activity is also why it requires careful safety monitoring. The key risk is progressive multifocal leukoencephalopathy (PML), a serious brain infection caused by the JC virus. Monitoring and risk stratification are central parts of how Tysabri is used in practice. [1]
Does Tysabri cure MS or stop progression permanently?
Tysabri helps control inflammatory activity, but it is not a cure. MS can continue to cause disability over time, and stopping treatment may allow disease activity to return in some patients. Decisions about starting, continuing, or switching are typically based on ongoing disease activity and individual risk factors. [1]
Sources
- https://www.drugs.com/mtm/tysabri.html