Safety Alerts & Recalls

What does this mean?

Tysabri (natalizumab) is used to treat serious condition such as multiple sclerosis and Crohn’s Disease and the benefits of use may continue to outweigh the risks for the majority of patients. If you are receiving treatment with Tysabri, please be aware of the following:

- Tysabri continues to be associated with PML.

- The risk of developing this disease increases with the number of Tysabri infusions received.

- The risk of developing PML also increases if you have taken a medication that suppresses the immune system (called an immunosuppressant) in the past. Tell your healthcare professional if you have previously taken an immunosuppressant medication such as mitoxantrone (Novantrone), azathioprine (Azasan, Imuran), methotrexate (Trexall), cyclophosphamide (Cytoxan), and mycophenolate (Cellcept).

If you have any concerns regarding this alert or your treatment with Tysabri then please discuss your concerns further with your own doctor or other healthcare professional.

Healthcare professionals and patients are encouraged to report adverse events or side effects from medications to the FDA's MedWatch Program by telephone at 1-800-332-1088, by fax at 1-800-332-0178, by mail at MedWatch, FDA, 5600 Fishers Lane, Rockville, MD 20852-9787, or on the MedWatch website at

FDA Issues Update on the Risk Of Progressive Multifocal Leukoencephalopathy With Tysabri

The Food and Drug Administration (FDA) has updated the Tysabri (natalizumab) Prescribing Information to give new information about the risk of progressive multifocal leukoencephalopathy (PML). PML is a rare but serious brain infection associated with use of Tysabri for the treatment of multiple sclerosis (MS) and Crohn's disease. The revised prescribing information includes a table summarizing rates of PML with Tysabri.

The FDA also warns about a new risk factor where patients receiving Tysabri infusions are at increased risk of developing PML if they have been treated in the past with medicines that suppress their immune system (called immunosuppressants). Examples of immunosuppressants are: mitoxantrone (Novantrone), azathioprine (Azasan, Imuran), methotrexate (Trexall), cyclophosphamide (Cytoxan), and mycophenolate (Cellcept). In addition to immunosuppressant use, the risk of developing PML also increases with the length of treatment with Tysabri, particularly when it is beyond two years.

For more information please visit: more information here

Source: FDA
Publication Date: 2011-04-25
Last Updated: 2011-04-25

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