Washington, DC: US health officials have warned that the multiple
sclerosis drug Tysabri (generic name natalizumab) can potentially cause a
fatal brain disorder and the risk is greater as patients receive more
infusions.
Two weeks after European regulators
announced the warning, on February 5, 2009 the FDA said the warning was
based on 31 confirmed cases (including eight deaths) of progressive
multifocal leukoencephalopathy (PML), a brain infection that can be
fatal. Still, the FDA website states that the clinical benefits of
Tysabri continue to outweigh the potential risks.
Tysabri
was temporarily withdrawn from the market in 2005 because of its link
to PML, but surfaced again in 2006. Since that time about 66,000 people
worldwide have been treated with the drug, which is given as a single
infusion every four weeks. In September the FDA said the PML rate
appeared to increase with the number of infusions but said at the time
it was not requiring any changes to the drug's warnings. Tysabri already
carries a boxed warning regarding the PML risk.
Federal
regulators have now posted a safety update to doctors and patients
confirming changes made to the label of Tysabri, to warn of the higher
risk with long-term use.
The manufacturer, Biogen Idec
Inc., is required to updates the number of PML cases each month to
doctors on request but no longer posts the figure on its website or
issues a press release. ...... Report and related articles in LawyersandSettlements.com
