FDA allows reintroduction of Tysabri, after review of Biogen's TOUCH scheme

US firm Biogen Idec and Ireland's Elan say that the Food and Drug Administration has approved a supplemental Biologics License Application for the reintroduction of the multiple sclerosis drug Tysabri (natalizumab). The firms went on to say that the FDA requires that labeling changes containing updated safety data informing patients of the risks associated with the drug be added to the product.

Originally withdrawn due to PML cases

Tysabri was originally withdrawn from sale by Biogen and Elan in February 2005 following the occurrence of three cases of progressive multifocal leukoencephalopathy, a rare but deadly brain disease, during Phase III trials. In response, the FDA put all further clinical examination of the drug on hold until February 2006 when a re-assessment of patients in the original program confirmed that there were no more PML cases.