What TYSABRI Does
There are 3 key ways TYSABRI impacts relapsing MS.
It's important to look at the big picture when evaluating an MS therapy. MS is a lifelong disease that silently advances, and there is no cure. But TYSABRI may make a real difference for you. Not only is it taken every 4 weeks as an infusion, but it's been proven to impact 3 key aspects of relapsing MS:
- Reduces flare-ups
- Slows down the progression of physical disability
- Reduces new brain lesions and new lesion activity

Understanding MS and TYSABRI
Take a closer look into how multiple sclerosis (MS) causes damage to the myelin sheath. You'll also see how TYSABRI is thought to impact relapsing MS.
1. Reduces flare-ups.
The results of a 2-year study showed that TYSABRI reduced how often flare-ups occurred by 67% compared to 41% with placebo
. The average number of flare-ups a person had each year was 0.22 for TYSABRI and 0.67 for placebo.

Of the 627 people who took TYSABRI in the 2-year study, more than 6 out of 10 had no flare-ups at all.
2. Slows down the progression of physical disability.
People who were treated with TYSABRI were 42% less likely to develop worsening physical disability — 29% of people who received a placebo had their physical disability worsen, versus only 17% of people who were treated with TYSABRI.

Of the 627 people who took TYSABRI in the 2-year study, more than 8 out of 10 had no physical disability progression.
Understanding physical disability progression
To see if your physical disability is progressing, doctors use a scale called the Expanded Disability Status Scale (EDSS). The EDSS is a way of measuring physical disability. One goal of MS treatment is to reduce physical disability progression past a score of 4.0 on the EDSS, a point at which disability starts to affect multiple things you do.
Because the disability progression of relapsing MS can happen slowly over time, it's easy to overlook. But don't be fooled. Relapsing MS is an advancing disease, and TYSABRI has been proven to slow physical disability progression.
Expanded Disability Status Scale (EDSS)

3. Reduces new brain lesions
and new lesion activity.
TYSABRI can also reduce the number of brain lesions, which are areas of badly damaged nerves
.
At the end of a 2-year study, 97% of people taking TYSABRI had no new brain lesions that showed disease activity, compared with 72% of people taking placebo. However, changes in MRI
often do not relate to how your MS is progressing.

Of the 627 people who took TYSABRI in the 2-year study, 9 out of 10 had no new lesions or new disease activity.
What we know about TYSABRI, and what we think we know
The exact way TYSABRI works is not fully understood, but TYSABRI appears to work differently than other MS treatments.
- TYSABRI is an antibody
, not an interferon
like AVONEX® (interferon beta-1a), Betaseron® (interferon beta-1b), Extavia® (interferon beta-1b), Rebif® (interferon beta-1a) or glatiramer acetate (Copaxone®).
- TYSABRI is thought to keep white blood cells
from getting into the brain and attacking nerves
. - Prohibiting these cells from attacking nerves is believed to result in fewer brain lesions† that cause multiple sclerosis symptoms. However, changes in MRI often do not relate to how your MS is progressing.
†Changes in MRI often do not relate to how your MS is progressing.




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