Last August, an FDA advisory panel voted 12-3 in favor of the use of the drug for Crohn's disease during a joint meeting of the Gastrointestinal Drugs Advisory Committee and the Drug Safety and Risk Management Advisory Committee.
At the time, the panel found that Tysabri could help ease the symptoms of the disease in patients who don't respond to standard therapies such as steroids or immunosuppressants.
The FDA is only approving Tysabri for Crohn's patients with moderate to severe symptoms, and this use will be subject to strict controls.
Korvick said that, besides the risk of PML, Tysabri also raises a patient's odds for hypersensitivity reactions, liver injury and severe herpes infections, especially in those on immunosuppressant therapy, so people taking immuno-suppressing drugs should not take Tysabri, Korvick said.
Crohn's patients who begin Tysabri therapy should also taper off their use of steroids, she added.
Side effects from the drug include headache, fatigue, infusion reactions, rash, and joint and limb pain.
"Because of these risks, patients, prescribers, pharmacies and infusion centers must all be enrolled in the [drug makers'] 'CD Touch' program and agree to comply with the company's strict monitoring guidelines," Korvick said. Doctors should also "evaluate Crohn's patients after three months of treatment to determine if they have improved on Tysabri. If not, then patients should be discontinued," she added.
According to the Wall Street Journal, Biogen Idec earlier this month noted that more than 21,000 patients were using Tysabri without any additional reports of PML.
There's more on Crohn's disease at the U.S. National Institute of Diabetes and
All rights reserved