Tysabri® Update: Trials Resume; Drug Remains off Market; FDA Holds Advisory Committee Meeting

February 28, 2006

Tysabri Trials Resume

Biogen Idec and Elan Corporation, makers of Tysabri® (natalizumab), report that the Food and Drug Administration (FDA) has removed the clinical hold on this drug for studies with multiple sclerosis (MS). This allows the companies to resume their clinical trials using Tysabri as a treatment for multiple sclerosis (MS). According to the FDA’s press release dated February 16, 2006, “ The removal of the clinical hold allows patients with MS who were previously treated with the drug under an investigational (IND) study to resume treatment in an IND study following discussion with their physicians about the potential risks and potential benefits of treatment.”

Drug Remains off Market; FDA Holds Advisory Committee Meeting

The FDA press release goes on to state, “ The drug is not being placed back on the market at this time. FDA has scheduled an Advisory Committee Meeting on March 7 and 8, 2006 to discuss an application for Tysabri for use in treating patients with relapsing forms of multiple sclerosis. Aspects for discussion include the risks associated with the drug, its efficacy in the treatment of multiple sclerosis relapses and disability, its possible return to the marketplace, and its proposed risk management plan(s).”

In addition to representatives from other MS agencies and pharmaceutical companies, as well as interested individuals from the MS community, MSAA President and CEO Doug Franklin will be attending the FDA’s Advisory Committee Meeting. Mr. Franklin will be speaking on behalf of MSAA and the individuals it serves, noting the importance of drug research for the treatment of MS, while stressing the urgency of patient safety and the need for precise safety data derived from rigorous clinical trials.

Background Information about Tysabri and Progressive Multifocal Leukoencephalopathy (PML)

Tysabri was given early approval in November 2004 by the FDA for the treatment of MS. The drug had shown initial success in clinical trials and was expected to be a strong candidate for the long-term treatment of relapsing-remitting MS. The drug was voluntarily suspended, however, in February 2005 after progressive multifocal leukoencephalopathy (PML) was confirmed in two patients taking both Tysabri and Avonex® (interferon beta-1a).

PML is an often-fatal brain disorder thought to be caused by the activation of a virus known as the “JC Virus.” This virus, which normally remains dormant in those with uncompromised immune-system function, may be present in most of the general population. Regarding the two MS-trial participants diagnosed with PML, the first patient died and the second patient survived in a debilitated state. A third case was discovered upon the re-examination of a patient who took Tysabri in the treatment of Crohn’s Disease and died in 2003.

Since the February 2005 voluntary suspension, Biogen Idec and Elan Corporation have conducted a safety evaluation of patients who previously took Tysabri. Any unusual responses to the drug were investigated and reported to the FDA. According to a press release from Biogen Idec and Elan, dated August 9, 2005, no new confirmed cases of PML have been discovered. Almost 2,000 MS patients from clinical trials participated in the safety evaluation.

According to the FDA’s press release from February 16, 2006, “ FDA has worked with Biogen-IDEC over the ensuing months to assess whether any other patients exposed to natalizumab had developed an early stage of PML, what factors might have been contributory to the three PML cases that did occur, to consider what procedures could be utilized to potentially decrease the risk of PML in the future, and how to suitably monitor patients to detect a PML infection as early as feasible.”

As more information becomes available, updates will be posted to MSAA’s website.

For More Information

The FDA provides the following links for additional information:

For further information, health care professionals and patients can visit FDA's website at: www.fda.gov/cder/drug/infopage/natalizumab/default.htm

Notice for the Peripheral and Central Nervous System Drugs Advisory Committee meeting: www.fda.gov/oc/advisory/accalendar/2006/cder12543d030706amd.html

Questions and Answers Regarding Lifting of the Clinical Hold on Tysabri (natalizumab)

For more information on Tysabri® from MSAA, please see:
"Antegren Update," "FDA Approves Tysabri® (formerly Antegren) for the Treatment of Multiple Sclerosis,""Voluntary Suspension of Tysabri® (Natalizumab) Marketing."   Anyone wishing additional information about MS and its treatments may contact MSAA's Helpline consultants by calling (800) 532-7667. Media questions should be directed to Andrea Borkowski at (800) 532-7667, ext. 123.

Written by Susan Wells Courtney, MSAA Senior Writer
Edited by Dr. Jack Burks, MSAA Vice President and Chief Medical Officer

Read all the Latest News...