Irish biotech group Elan and US partner Biogen Idec have restarted trials of the multiple sclerosis (MS) drug Tysabri.
The drug was earlier withdrawn from testing following the death of two clinical trials patients. The resumption of testing follows a move earlier this month by
US drug regulators to delay the expected return of Tysabri to market.
However, although the Food and Drug Administration (FDA) informed Elan and Biogen that it would need up to 90 more days to consider a revised risk management plan put forward by the companies for the drug, the delay does not affect clinical trials of the drug.
Elan had previously voluntarily suspended Tysabri from the US market and dosing in all ongoing clinical trials based on reports of progressive multifocal leukoencephalopathy (PML), a rare and potentially fatal, demyelinating disease of the central nervous system.
A safety evaluation of more than 3,000 Tysabri patients was done by Elan and Biogen in collaboration with leading experts in PML and MS. The results of the safety evaluation yielded no new confirmed cases of PML beyond the three previously reported.
The companies are expecting a decision by the FDA by June 28th.