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Treatments > Medications Used In MS

Brand Name Chemical Name

(formerly called Antegren)

Natalizumab (na-ta- lie -zoo-mab)

Primary Usage in MS

Generic Available
Disease-modifying agent No
This medication is given by IV infusion.

Tysabri is a laboratory-produced monoclonal antibody. It is designed to hamper movement of potentially damaging immune cells from the bloodstream, across the “blood-brain barrier” into the brain and spinal cord. Tysabri was evaluated in a pair of two-year, controlled clinical trials:

  • Study I compared Tysabri to placebo in patients who had not received any interferon-beta or glatiramer acetate for at least the previous six months.
  • Study II involved patients who had experienced one or more relapses while on treatment with Avonex. Half of the group took Tysabri in addition to their Avonex; half of the group took Avonex plus a placebo.

In both studies, those taking the medication had a reduced risk of disability progression and experienced fewer exacerbations (relapses) compared with the group taking a placebo. At the present time, safety and efficacy of treatment with Tysabri beyond two years are not known. Tysabri has not been studied in people with primary progressive MS or in children.

Tysabri increases the risk of progressive multifocal leukoencephalopathy (PML), a viral infection of the brain that usually leads to death or severe disability. Although the cases of PML that occurred in the clinical trials occurred only in patients who were also taking another immunodulating or immunosuppressing medication, there were too few cases to rule out the possibility that PML can occur in patients taking Tysabri alone.

Based on post-marketing experience with Tysabri, the FDA has added an additional warning to the product's labeling information. Tysabri has been found to increase the risk of liver damage, even after a single dose. Any person experiencing symptoms resulting from abnormal liver function, including yellowing of the skin and eyes (jaundice) unusual darkening of the urine, nausea, feeling tired or weak, and vomiting, should contact his or her physician immediately.. Blood tests can be done to check for liver damage. Treatment with Tysabri should be discontinued in anyone with jaundice or laboratory findings that indicate significant liver injury.

Medication Index

Other Medications Used as Disease-Modifying Agents

The Disease-Modifying Drugs
Information on the disease-modifying drugs (Betaseron, Avonex, Copaxone, Novantrone, Rebif, and Tysabri). Includes how each is taken, side effects, benefits, and available help.

Tysabri FAQs (PDF)

Is an Oral Disease-Modifying Drug on the Horizon?
February 2006

National MS Society Disease Management Consensus Statement
Early intervention recommendations by the Medical Advisory Board of the National MS Society regarding use of the current MS disease-modifying agents

About Monoclonal Antibodies


Approval by the U.S. Food and Drug Administration (FDA)
Tysabri was approved by the U.S. Food and Drug Administration (FDA) in 2006 as a monotherapy (not to be used in combination with another disease-modifying therapy) for the treatment of patients with relapsing forms of MS to delay the accumulation of physical disability and reduce the frequency of clinical exacerbations. Because Tysabri increases the risk of PML, it is generally recommended for patients who have had an inadequate response to, or cannot tolerate, any of the other disease-modifying therapies that are available for treating MS (see Precautions)

Proper Usage
Tysabri is given once every four weeks by intravenous infusion.

Because of the risk of PML, Tysabri is available only through a special distribution program called the TOUCH™ Prescribing Program. Only physicians, infusion centers, and pharmacies associated with the infusion centers that are registered with the Program can prescribe or deliver the medication. And only those patients who are enrolled in, and meet all the conditions for the Program, can receive this medication.

Before starting treatment with Tysabri, you will learn about the TOUCH™ program and be asked to sign the Prescriber/Patient Enrollment Form.

Prior to each infusion, you will be asked a series of questions by the doctor or nurse at the infusion center to confirm that Tysabri is still appropriate and safe for you.

Do not take Tysabri if you have PML or are allergic to Tysabri.

Do not take Tysabri if you have a medical condition that can weaken your immune system, such as HIV infection or AIDS, leukemia or lymphoma, an organ transplant, or others.

Do not take Tysabri if you are taking any medication(s) that can weaken your immune system.

Before each infusion, tell doctor or nurse at the infusion center:

  • About all medications you are taking (prescription and non-prescription, including supplements)
  • About all of your medical conditions
  • If you have any new or worsening medical problems (such as changes in your thinking, eyesight, balance, strength, etc.
  • If you experienced any hives, itching, or trouble breathing during or after an infusion of Tysabri
  • If you have a fever or infection (including long-lasting infections or shingles)
  • If you are pregnant or plan to become pregnant
  • If you are breastfeeding

Plan to see the doctor who prescribed Tysabri for you three months after the first infusion, six months after the first infusion, and at least as frequently as every six months thereafter.

Tysabri should not be used during pregnancy or by any woman who is trying to become pregnant. Women taking Tysabri should use birth control measures at all times. If you want to become pregnant while being treated with Tysabri, discuss the matter with your physician. If you become pregnant while using Tysabri, contact your physician.

No data are available on the effects of vaccination in patients receiving Tysabri.

Possible Side Effects
Side effects that may go away as your body adjusts to the medication and do not require medical attention unless they continue or are bothersome: headache, pain in your arms or legs*, feeling tired*, joint pain, depression*, diarrhea, pain in the stomach area.

Allergic reactions can occur—including serious ones. Symptoms of an allergic reaction can include: hives, itching, trouble breathing, chest pain, dizziness, chills, rash, nausea, flushing of skin, low blood pressure. Serious allergic reactions usually happen within 2 hours of the start of the infusion, but can happen any time after. Contact your physician promptly about any of these.symptoms.

Because Tysabri affects your immune system, it can increase your chance of getting an unusal or serious infection, such as pneumonia, serious urinary tract infection, gastroenteritis, vaginal infection, tooth infection, and others. Contact your physican promptly about any problems of this kind.

Additional information about Tysabri is available from:
Biogen Idec, Inc.

Reprinted with permission from Rosalind C. Kalb (ed.), Multiple Sclerosis: The Questions You Have—The Answers You Need (4th ed.). New York: Demos Medical Publishing, 2007.

Last updated February 27, 2008