European regulators have concluded that multiple sclerosis therapy Tysabri® (natalizumab) should come with a warning about a potentially higher risk of liver damage in patients taking the drug.
The move follows a review by the EMEA’s Committee for Medicinal Products for Human Use of 29 reports of liver injury in patients treated with Tysabri, with signs of substantially elevated hepatic enzymes and bilirubin (a breakdown product of haemoglobin) observed as early as six days after the first dose was administered.
The drug is made by US group Biogen Idec and Irish firm Elan.
The decision comes shortly after a similar move by US regulators in February, which saw Biogen warn of potential risks of higher levels of hepatic enzymes and bilirubin – a key marker of severe liver injury that could lead to the need for a liver transplant or even to patient death – in a letter to healthcare professionals, shortly after a similar warning was added to the drug’s label for its Crohn’s disease indication.
Doctors on both sides of the Atlantic have been advised to closely monitor the liver function of patients taking Tysabri, and it was stressed that therapy should be discontinued in those deemed at risk.
This is not the first time Tysabri’s safety profile has been under review. The drug first hit the market in 2004, but was promptly taken off the market in March 2005 after three patients developed a potentially fatal brain infection, progressive multifocal leukoencephalopathy.
However, following an extensive safety review by US and European regulators, Tysabri was allowed to return to pharmacy shelves in July 2006 for the treatment of MS, with certain restrictions, as regulators felt that as long as patient were aware of the risks they could benefit from its use.