Natalizumab (Tysabri) and progressive multifocal leukoencephalopathy (PML)
admin September 22nd, 2009
The FDA have reported on a continuing number of reports of progressive multifocal leukoencephalopathy associated with natalizumab:
From July 2006, (when Tysabri marketing resumed) to September 8, 2009, 13 reported cases of Tysabri-related PML were confirmed worldwide in patients being treated for MS with Tysabri monotherapy. There have been no postmarketing reports of PML in patients treated with Tysabri for Crohn’s disease. Less than 2% of Tysabri use in the U.S. has been in patients with Crohn’s disease. Based on available data from the U.S. and outside of the U.S., the current rate of PML in patients who have received at least 24 infusions ranges from 0.4 to 1.3 per 1,000 patients.
The risk appears to increased with the number of infusions administered.
- FDA
- Comments Off