Contact Us

*    Denotes required field.

   * First Name 

   * Last Name 

   * Email 


Cell Phone 

Street Address 

Zip Code 



Date you started taking this drug:

Date you stopped taking this drug:

Please describe side effects:

For verification purposes, please answer the below question:

No Yes, I agree to the Parker Waichman LLP disclaimers. Click here to review.

Yes, I would like to receive the Parker Waichman LLP monthly newsletter, InjuryAlert.

please do not fill out the field below.


Feb 28, 2005 |

Biogen Idec (NASDAQ: BIIB) and Elan Corporation, plc (NYSE: ELN) announced today a voluntary suspension in the marketing of TYSABRI® (natalizumab), a treatment for multiple sclerosis (MS). The companies are suspending supply of TYSABRI from commercial distribution and physicians should suspend dosing of TYSABRI until further notification. In addition, the companies have suspended dosing in all clinical trials.

This decision is based on very recent reports of two serious adverse events that have occurred in patients treated with TYSABRI in combination with AVONEX® (Interferon beta-1a) in clinical trials. These events involve one fatal, confirmed case and one suspected case of progressive multifocal leukoencephalopathy (PML), a rare and frequently fatal, demyelinating disease of the central nervous system. Both patients received more than two years of TYSABRI therapy in combination with AVONEX.

The companies’ actions have been taken in consultation with U.S. Food and Drug Administration (FDA). Worldwide regulatory agencies are being kept informed.

The companies will work with clinical investigators to evaluate TYSABRI-treated patients and will consult with leading experts to better understand the possible risk of PML. The outcome of these evaluations will be used to determine possible re-initiation of dosing in clinical trials and future commercial availability.

"Our ongoing commitment to MS patients has led us to take these steps," said Burt Adelman, MD, executive vice president, Development, Biogen Idec. "Because we believe in the promising therapeutic benefit of TYSABRI, we are working to evaluate this situation thoroughly and expeditiously. While we work through this matter, we must place patient safety above all other considerations."

"We are working with leading experts and regulatory agencies to responsibly investigate these events and to develop the appropriate path forward," said Lars Ekman, MD, executive vice president and president, Research and Development, Elan. "Our primary concern is for the safety of patients."

In total, approximately 3,000 patients have been treated with TYSABRI in clinical trials of MS, Crohn’s disease, and rheumatoid arthritis. To date, the companies have received no reports of PML in MS patients receiving TYSABRI monotherapy or in patients with Crohn’s disease or rheumatoid arthritis in TYSABRI clinical trials. Biogen Idec has received no reports of PML in patients treated with AVONEX alone, a product that has been on the market since 1996.

Related articles
Parker Waichman Accolades And Reviews Best Lawyers Find Us On Avvo