FDA sees limits to Biogen MS drug
Doubts rise on use of it for Crohn's
Biogen Idec Inc. and Elan Corp.'s multiple sclerosis drug Tysabri may not treat the bowel disease Crohn's better than existing therapies, US regulators said.
Studies by Elan, Ireland's biggest drug maker, also don't show that Tysabri has the same level of effectiveness in Crohn's disease as in multiple sclerosis, Food and Drug Administration staff members said in documents posted yesterday on the agency's website. A panel of outside advisers to the FDA will meet Tuesday to recommend whether Tysabri should be approved to treat Crohn's disease.
Tysabri was returned to the market in July 2006 as a treatment for multiple sclerosis after a 17-month suspension because of its link to a rare, fatal brain disorder. The FDA cleared Tysabri for MS because of studies showing it was twice as effective as existing therapies. That's not the case for patients with Crohn's disease, FDA staff members said.
"The benefit and risk considerations in the Crohn's disease population are considerably different from those in the MS population," FDA staff reviewers said in the report. "The treatment effect in the Crohn's disease population was not as high as that in the MS population nor is it clearly distinguished from approved Crohn's disease therapies."
The FDA advisers, meeting in Gaithersburg, Md., will be asked to consider whether Tysabri's safety can be adequately monitored in Crohn's patients and whether its effectiveness in treating the disease is worth the risk. The FDA usually follows the recommendations of its advisers, although it isn't required to do so.
Biogen shares fell $1.18, or 2 percent, to $57.01 in Nasdaq Stock Market composite trading. The stock has risen 16 percent this year. Elan's American depositary receipts declined 69 cents, or 3.5 percent, to $19.04. One ADR equals one common share.
European regulators on July 19 rejected Tysabri as a treatment for Crohn's, citing insufficient evidence the drug worked against the bowel disorder. Biogen, based in Cambridge, and Elan are appealing the decision.
The FDA approved Tysabri on Nov. 23, 2004, based on results from one-year studies. Biogen and Elan voluntarily withdrew the drug on Feb. 28, 2005, because of two cases of a fatal disorder, progressive multifocal leukoencephalopathy. A month later, the companies disclosed a third case of PML involving a patient with Crohn's disease who took Tysabri in a clinical trial. Two of the three PML patients died.
