In October 2007, the Federal Drug and Food Administration (FDA) issued information for healthcare professionals regarding the subcutaneous use of exenatide (Byetta, Amylin Pharmaceuti-cals).9 Since then, the FDA has received at least six additional case reports of necrotizing or pancreatitis in patients taking exenatide.
Of these six cases, all patients needed hospitalization, two patients died, and four were recovering at the time of the reporting. Exenatide was discontinued in all of these patients.
If pancreatitis is suspected, exenatide and other potentially suspect drugs should be discontinued. There are no signs or symptoms distinguishing acute hemorrhagic or necrotizing pancreatitis associated with exenatide from less severe forms of pancreatitis. If pancreatitis is confirmed, appropriate treatment should be initiated and patients should be carefully monitored until they fully recover. Exenatide should not be restarted. The FDA is working with Amylin Pharmaceuticals to add stronger and more prominent warnings to the product label regarding the noted risks.
Since the last warning of natalizumab injection (Tysabri, Biogen IDEC), the FDA has informed healthcare professionals of two new cases of progressive multifocal leukoencephalopathy (PML) in European patients receiving it for more than a year as monotherapy for multiple sclerosis (MS).10
The agent currently is FDA approved to treat multiple sclerosis and Crohn’s disease. Approximately 39,000 patients have received treatment worldwide, with approximately 12,000 patients receiving treatment for at least a year. No new cases have been reported in the U.S., where approximately 7,500 patients have received the drug for more than a year and approximately 3,300 have received the drug for more than 18 months.
The FDA still believes natalizumab monotherapy may confer a lower risk of PML than usage with other immunomodulatory medications. Prescribing information for natalizumab has been revised to reflect this new information. TH
Michele B. Kaufman, PharmD, BSc, RPh, is a registered pharmacist based in New York City.
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