Tysabri is approved as single therapy for the treatment of people with relapsing forms of multiple sclerosis (MS) to reduce the frequency of flare-ups and delay progression of physical disability.
After the FDA initially approved Tysabri, the drug's manufacturer took the drug off the U.S. market due to reports of a rare, but serious brain infection called PML (progressive multifocal leukoencephalopathy). But the drug returned to the market after the drugmaker included a risk-minimization program with mandatory patient registration and periodic follow-up to identify any possible cases of PML as soon as possible.
For Mimi Mosher, a person with primary progressive MS, clarity first came
when she lost her vision.
Her eyesight steadily eroded by multiple sclerosis, Mimi now lived in a
near-constant dusk. The realization came at a scary time. “I was driving. I
thought, I can’t do this anymore. I had to pull off the road and let my friend
drive,” says Mimi.
Until then, Mimi had been living “in a deep state of denial” about her
advancing symptoms. As her primary progressive MS forced her to hand over her
The risk for PML increases with the number of doses received. Data that's been collected by the FDA indicates the risk is 0.3 per 1,000 patients treated for up to 24 months, 1.5 per 1,000 patients treated for 25-26 months, and 0.9 per 1,000 patients treated for 37-48 months.
Risk also is higher among patients treated with immune-suppressing therapy before using Tysabri. Because of this risk, Tysabri is usually recommended for patients who cannot tolerate or have not responded to other MS treatments.
Tysabri is unique among MS drugs in that it works by binding to a protein found on the surface of immune cells (white blood cells), which are believed to play a role in the damaging effects of MS. Tysabri, a monoclonal antibody, curbs the ability of white blood cells to enter the brain and spinal cord.
Who Should Receive Tysabri for Multiple Sclerosis
Tysabri can be prescribed to treat patients who have relapsing forms of multiple sclerosis. The drug reduces the frequency of MS attacks and delays worsening of physical disability.
How Is Tysabri Given for Multiple Sclerosis?
Tysabri is given to those with multiple sclerosis intravenously (through a vein) over the course of an hour every four weeks in a doctor's office.
It is important that patients are observed for one hour after each infusion in case an allergic reaction develops. Symptoms of allergic reactions include hives, itching, breathing problems, chest pain, nausea, flushing, dizziness, and rash.
Besides PML and allergic reactions, other serious side effects include liver damage and serious infections.
As is the case with all medications, it is important to weigh the risks and benefits carefully. Talk to your doctor to determine if this treatment is right for you.