What is Tysabri?

Tysabri (natalizumab) is a prescription medication for adult patients with relapsing forms of multiple Sclerosis. It is shown in clinical studies to slow the worsening of disability caused by MS and decrease the number of flare-ups, or relapses. Tysabri may also improve mental function in some patients. Tysabri works in a different way than other MS drugs by inhibiting white blood cells from getting into the brain and spinal cord and attacking nerves. It is generally recommended for patients who do not improve with, or can't tolerate other medications used to treat MS. This is because Tysabri increases the risk of progressive multifocal leukoencephalopathy (PML), a rare brain infection that can cause death or severe disability.

The Multiple Sclerosis Clinic at Virginia Mason is a registered clinic in the Tysabri Outreach: Unified Commitment to Health® (TOUCH) Prescribing Program, designed to educate and monitor all patients receiving Tysabri therapy. For more information about the TOUCH Prescribing Program and Tysabri, call the Multiple Sclerosis Clinic at (206) 341-0420.

Frequently Asked Questions (FAQs) About Tysabri

  1. Who should take Tysabri?
  2. Is Tysabri more effective than other MS medications?
  3. What makes Tysabri different?
  4. What are the possible side effects of Tysabri?
  5. How can I receive Tysabri?
  6. Can I find out if I have been exposed to the virus that causes PML?


1. Who should take Tysabri?
Patients should work closely with their doctor to determine if Tysabri is the right step in their treatment. The indications for treatment with Tysabri include an inadequate response or inability to tolerate other MS drug regimens. Tysabri is indicated for relapsing forms of MS, meaning that patients with progressive forms of the disease who still experience relapses may be candidates for the therapy.

2. Is Tysabri more effective than other MS medications?
In a two-year study, some patients taking Tysabri experienced no relapses or flare-ups, no apparent disease progression and no new or newly active lesions seen on MRI. Overall, studies showed a 68 percent reduction in relapses, as opposed to a one-third reduction from interferon or glatiramer acetate-based medications. Also, Tysabri is the only MS therapy that has been shown to improve mental function and physical disability in some patients.

3. What makes Tysabri different?
Tysabri is an antibody against a gatekeeper molecule on blood vessels and is thought to work by preventing white blood cells from crossing the blood-brain barrier into the brain and spinal cord, preventing damage to nerves. Keeping white blood cells from attacking nerves is believed to result in fewer brain lesions that cause MS symptoms.

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4. What are the possible side effects of Tysabri?

The rarest, but most dangerous possible side effect of Tysabri is a brain infection called progressive multifocal leukoencephalopathy (PML). PML can occur in people with weakened immune systems. That's why Tysabri is not recommended for patients who have a medical condition that causes a weakened immune system, such as HIV/AIDS, leukemia, lymphoma, an organ transplant, and others. Also, patients taking medications that weaken the immune system may be at risk. All current medications must be reviewed prior to treatment with Tysabri.

Other serious side effects include allergic reactions and infections. Dangerous allergic reactions usually happen within two hours of receiving the Tysabri infusion, but they can also happen later. Patients are monitored for allergic reaction during the infusion and after by watching for symptoms such as:

  • hives
  • chills
  • itching or rash
  • breathing problems
  • nausea
  • chest pain
  • flushing of skin
  • dizziness
  • low blood pressure

More common Tysabri side effects can include:

  • headache
  • fatigue
  • urinary tract infection
  • lung infection
  • vaginitis
  • joint pain
  • diarrhea
  • rash
  • depression

5. How can I receive Tysabri?
Tysabri is prescribed by doctors who are enrolled in the TOUCH® Prescribing Program, at designated infusion centers. Patients also enroll in TOUCH to ensure proper monitoring and follow-up while undergoing Tysabri therapy. The TOUCH program and the Multiple Sclerosis Clinic at Virginia Mason make safety for every patient a priority. Patients receive a thorough evaluation prior to starting Tysabri, and will be monitored at each monthly infusion, with a full examination every three to six months during treatment. The TOUCH program was designed with help from the Food and Drug Administration to catch any potential PML cases as early as possible, as well as prevent them.

For more information about Tysabri or the TOUCH Prescribing Program, call the Multiple Sclerosis Clinic at (206) 341-0420.

6. Can I find out if I have been exposed to the virus that causes PML?
Yes. In winter 2011, a commercially available blood test, STRATIFY JCV™ Antibody, became available to test for evidence of exposure to the JC virus. Individuals who have a negative result on this test have a much lower risk of developing PML while taking Tysabri. We recommend that patients thinking about going on Tysabri have this test done to better understand the risk of PML. For those patients on Tysabri already we routinely follow this test result to monitor for changes and have ongoing discussions about your specific PML risks.

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