FDA Clears Tysabri For Limited Clinical Use
This article was originally published in The Pink Sheet Daily
Executive Summary
Patients who had previously been receiving the multiple sclerosis therapy are now eligible to participate in Biogen Idec/Elan’s pending safety extension study.
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FDA's decision to remove the clinical hold on Biogen Idec/Elan's multiple sclerosis therapy Tysabri (natalizumab) could pave the way for re-entry of the product to the marketplace. Patients who had been receiving Tysabri within an IND study at the time of the product's suspension in February 2005 will be eligible to participate in the open-label, multi-center safety extension study that Biogen and Elan plan to initiate in the coming weeks. The IND study has "very specific plans for close monitoring of patients," FDA says in a Q&A document posted on its website Feb. 15. "Biogen has not proposed to administer the drug to anyone who had not previously been receiving it under an IND study," the agency notes. FDA based its decision on the safety evaluation conducted by the companies of more than 3,000 patients who had received natalizumab in clinical studies under an IND. The evaluation found no additional cases of progressive multifocal leukoencephalopathy. The safety extension study will give FDA a test run for any risk management programs that would be implemented if Tysabri is brought back to the market. FDA says it remains "very concerned about the potential for PML associated with natalizumab," but notes that it cannot determine the level of risk based on available data. Furthermore, "existing efficacy data with natalizumab indicate this is a very effective product and multiple sclerosis is a devastating neurologic disease," the agency states. As a result, "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," FDA concludes. Tysabri will be reviewed March 7-8 by FDA's Peripheral & Central Nervous System Drugs Advisory Committee (1 (Also see "Tysabri To Go Before Advisory Committee On March 7" - Pink Sheet, 23 Jan, 2006.)). The eighth was added as an extra day because of the large number of patients that requested to testify. [ Editor 's note : To 2 watch a webcast or order a video/DVD of this meeting, visit FDAAdvisoryCommittee.com.] The sBLA for Tysabri, filed in September 2005, was granted priority review and has a late-March user fee date (3 (Also see "Biogen Idec/Elan Resubmit Tysabri With New Risk Management Program" - Pink Sheet, 26 Sep, 2005.)). -Kathryn Phelps |