Drug regulators are standing by a multiple sclerosis drug that has been associated with a potentially-deadly brain infection.
Pharmacy News revealed yesterday that Tysabri (natalizumab) has been linked to 10 cases of progressive multifocal leukoencephalopathy (PML) across the world since 2006, with the latest case occurring as recently as 23 June.
The Therapeutic Goods Administration (TGA) confirmed that no cases of PML in Tysabri patients had been reported in Australia to date and said it would monitor the situation.
"The benefits of this drug in a serious and disabling medical condition are considered significant," a TGA statement said.
The drug's product and consumer information already carried a black box warning about its association with the condition, the TGA said.
Tysabri was temporarily taken off the US market in 2005 due initial concerns of a link to PML but registered in Australia in November, 2006.
The drug's manufacturer, Biogen Idec, said it was not considering taking it off the market again.
"Tysabri's benefits clearly outweigh its risks," Biogen Idec spokesman Jose Juves said.
"To date, the rate of PML in Tysabri-treated patients is lower than originally seen in the clinical trials. Nine of the 10 patients diagnosed with PML since 2006 are alive, telling us that PML may not be uniformly fatal in Tysabri-treated patients.
"Overall, PML is occurring less frequently and may be less fatal than originally thought when Tysabri was approved."