This Is MS - Tysabri Cleared for Clinical Trial Use | Unbiased Multiple Sclerosis Research, News, and Community

Today the United States Food and Drug Adminisration took the first step (presumably) towards making Tysabri available to the public again, by clearing its usage in clinical trials.

As the history goes, the drug was voluntarily suspended from dosing, in clinical trials and to the public, in February of 2005, after three Tysabri-exposed patients developed progressive multifocal leukoencephalopathy (PML). Two of those patients died, while little is known about the welfare of the third asides from clinical stabilization.

There are many interesting facets at play here-- we would in fact expect no less from the drug known in the multiple sclerosis community as much for its drama as its promised efficacy.

The drug has only been cleared for clinical trial usage *in patients previously on Tysabri.* In other words, this particular decision is not opening the door for widespread post-marketing (Phase IV) clinical trials on new patients.

That being said, re-dosing in clinical trials is a necessary but not sufficient step towards eventual re-introduction to the broad market. In short, this is a highly positive (and in fact required) move for those that would like access to Tysabri in the future.

The re-initation of this trial may lead to allowing the various trials of other drugs similar to Tysabri that were halted after the PML discoveries. One such drug is Novartis' FTY720.

The FDA advisory committe, tasked with determining whether Tysabri should be allowed to be brought back onto the public market or not, is to be held on March 7.

In their note on the release of the clinical trial hold, the FDA continued to express natural reservations about the the PML risk: "FDA remains very concerned about the potential for PML associated with natalizumab (Tysabri) use."

FDA feels the clinical trials will help illuminate that risk:"Therefore, if a study is done in a manner that provides as much safety monitoring as feasible, it is reasonable to resume studying this product under IND to obtain more safety-related information that may permit us to begin to better understand how large or small the true risks associated with natalizumab are."

That statement makes it seem like the trials will need to run for a significant time before re-marketing the drug to the public. However, the FDA then says: "the existing efficacy data with natalizumab indicate this is a very effective product and multiple sclerosis is a devastating neurologic disease."

Unconfirmed, but interesting: During the Biogen investor conference call held today, it was apparently announced that the advisory committee meeting has been extended an extra day. Speculation as to why more time is necessary is rampant, but the most obvious explanation might be the large amount of public testimony that is expected to occur via the patient community.

So there you have it, the push and pull. The FDA acknowledges both the strong efficacy data and an at-risk patient community that needs new treatment alternatives, *as well as* the as-yet-unknown, but certainly very low risk of PML. The critical factor in the availability of Tysabri within the next year will be whether the FDA become convinced that it is "safe enough," so to speak, to allow the public to receive the proven benefits of Tysabri while being exposed to an indeterminate but potentially deadly risk.

The happy medium would be to re-allow Tysabri but impose very strict and effective patient monitoring methods to ensure PML does not develop and/or lead to another fatality-- at least until it is completely understood when and where this devastating side effect develops. An intrepid reader will of course note that this scenario is exactly what will be happening with the re-initiation of the clinical trials. You are left to your own conclusions, but the plot continues to get thicker in the MS community's quest for an alternative to the NCRABs.

Click "read more" for the official press release, as well as links to the FDA's Question and Answer page.

Relevant Links

FDA Questions & Answers Link on Tysabri's Clinical Trial Release

Official Press Release

Press Release Source: Biogen Idec and Elan Corporation, plc.

TYSABRI(R) Multiple Sclerosis Clinical Trial Hold Lifted by FDA Wednesday February 15, 2:28 pm ET Biogen Idec and Elan to Resume Clinical Trial Dosing in MS

CAMBRIDGE, Mass. and DUBLIN, Ireland--(BUSINESS WIRE)--Feb. 15, 2006--Biogen Idec (NASDAQ: BIIB - News) and Elan Corporation, plc. (NYSE: ELN - News) announced today that the Food and Drug Administration (FDA) informed the companies that they have removed the hold on clinical trial dosing of TYSABRI® (natalizumab) in multiple sclerosis (MS) in the U.S. The companies expect to begin an open label, multi-center safety extension study of TYSABRI monotherapy in the U.S. and internationally in the coming weeks. Patients who previously participated in the Phase III MS program are eligible for entry.

Biogen Idec and Elan had previously voluntarily suspended TYSABRI from the U.S. market and all ongoing clinical trials based on reports of progressive multifocal leukoencephalopathy (PML), a rare and potentially fatal, demyelinating disease of the central nervous system. Biogen Idec and Elan completed a comprehensive safety evaluation of more than 3,000 TYSABRI patients in collaboration with leading experts in PML and MS. The results of the safety evaluation yielded no new confirmed cases of PML beyond the three previously reported.

On September 26, 2005 the companies announced that they submitted a supplemental Biologics License Application to the FDA. Subsequently, the FDA designated TYSABRI for Priority Review. The FDA grants Priority Review status to products that are considered to be potentially significant therapeutic advancements over existing therapies that address an unmet medical need. Based on the FDA's designation of Priority Review for TYSABRI in MS, the companies anticipate action by the Agency approximately six months from the submission date, or by late March 2006. The FDA's Peripheral and Central Nervous System Drugs Advisory Committee will review TYSABRI on March 7 and 8, 2006.

About Biogen Idec

Biogen Idec creates new standards of care in oncology, neurology and immunology. As a global leader in the development, manufacturing, and commercialization of novel therapies, Biogen Idec transforms scientific discoveries into advances in human healthcare. For product labeling, press releases and additional information about the company, please visit http://www.biogenidec.com.

About Elan

Elan Corporation, plc is a neuroscience-based biotechnology company committed to making a difference in the lives of patients and their families by dedicating itself to bringing innovations in science to fill significant unmet medical needs that continue to exist around the world. Elan shares trade on the New York, London and Dublin Stock Exchanges. For additional information about the company, please visit http://www.elan.com.

Safe Harbor/Forward Looking Statements

This press release contains forward-looking statements regarding the initiation of clinical studies of TYSABRI in MS. The initiation of clinical studies is subject to a number of risks and uncertainties. Factors which could cause actual results to differ materially from the companies current expectations include the risk that concerns may arise from additional data or analysis or that the companies may encounter other unexpected delays or hurdles. Drug development and commercialization involves a high degree of risk. For more detailed information on the risks and uncertainties associated with the companies' drug development and other activities, see the periodic reports that Biogen Idec and Elan have filed with the Securities and Exchange Commission. The companies assume no obligation to update any forward-looking statements, whether as a result of new information, future events or otherwise

Contact:
Media Contacts:
Biogen Idec
Amy Brockelman, 617 914 6524
or
Elan
Davia B. Temin, 212 407 5740
Elizabeth Headon, 353-1-498-0300
or
Investor Contacts:
Biogen Idec
Oscar Velastegui, 617 679 2812
or
Elan
Emer Reynolds, 353 1 709 4000
Chris Burns, 800 252 3526
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Source: Biogen Idec and Elan Corporation, plc.