| Tysabri Update
I am posting this excerpt from the San Diego Union Tribune for those who may be interested.
MS drug is given second chance
But Tysabri faces FDA restrictions
By Penni Crabtree
UNION-TRIBUNE STAFF WRITER
June 6, 2006
Federal regulators yesterday approved the return of Biogen Idec and Elan Corp.'s multiple sclerosis drug Tysabri, but restrictions are likely to put an initial damper on patient use and the companies' profits.
Tysabri appeared destined to become the treatment of choice for multiple sclerosis when it was given accelerated approval in November 2004, and Wall Street analysts pegged its peak revenue potential at up to $3 billion annually.
But the companies, both of which have research or administrative hubs in San Diego, yanked the drug from the market three months later after it was linked to a rare brain disorder called progressive multifocal leukoencephalopathy, or PML. Three patients who took Tysabri during clinical trials contracted PML; two of them died.
The Food and Drug Administration rarely gives a therapy a second chance once it is removed because of safety concerns. The decision yesterday came only after the companies and the FDA completed a meticulous reassessment of the safety and health benefit data surrounding Tysabri.
In Tysabri's favor: patients who took the drug during clinical trials had a 66 percent reduction in relapses, compared with patients who took a placebo. And those who took the drug with Biogen Idec's older MS medicine, Avonex, had 54 percent fewer relapses than patients given Avonex alone
Less well defined are Tysabri's dangers. People taking Tysabri appear to face a 1-in-1,000 risk of contracting PML, which is caused by a virus that remains dormant in healthy adults but can be activated when the immune system is compromised.
The three Tysabri patients who contracted PML had weakened immune systems or were taking immune-suppressing drugs. “In this case, we made the assessment that the benefits of this drug outweigh the risks for MS,” Dr. Steven K. Galson, director of the FDA's Center for Drug Evaluation and Research, said at a news conference. “We are certain that patients are willing to take this risk because of the potential benefits of the drug.”
A plan approved by the FDA to reduce the PML risk comes with some strict requirements. For instance, the FDA recommended that Tysabri only be prescribed for patients who have not responded adequately to, or can't tolerate, other MS drugs. And Tysabri can't be used in combination with other drugs that suppress the immune system, the FDA said.
In addition, doctors, infusion centers and pharmacies must register with the companies before prescribing Tysabri, which is given to patients as a once-monthly infusion. And patients must also register so they can be regularly monitored and any new cases of PML reported.
Shares of Biogen Idec fell 5 percent, or $2.32, to close at $45.39. Shares of Elan fell 13 percent, or $2.46, to close at $16.52. Biogen Idec and Elan executives said the FDA restrictions still allow for a lot of prescribing leeway. About 100,000 U.S. patients taking medication for relapsing MS are dissatisfied with their treatment, and 50,000 more have stopped therapy because they can't tolerate the side effects or have other problems, said Dr. Burt Adelman, Biogen Idec's executive vice president of research and development.
“There is a tremendous pent-up demand for new therapies in the MS community,” Adelman said. The companies plan to relaunch Tysabri next month. Some stock analysts predict the drug could reach peak sales of $1 billion.
“In the big picture, this is the start of something that could be very positive,” said John McCamant, editor of the Medical Technology Stock Letter. “The FDA is essentially making the companies run a de facto Phase 4 clinical trial, to follow the patients and build a patient safety database.
“And if that safety data proves to be good, it will be excellent marketing fodder down the road,” McCamant said. | 
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