"A warning about hepatotoxicity has been added to the prescribing information. Signs of liver injury, including markedly elevated serum hepatic enzymes and elevated total bilirubin occurred as early as six days after the first dose, according to the letter, which is signed by Dr. Michael Panzara, Biogen's chief medical officer of neurology, and Dr. Gordon Francis, Elan's senior vice president of global clinical development.
'Signs of liver injury have also been reported for the first time after multiple doses,' the letter added. 'In some patients, liver injury recurred upon rechallenge, providing evidence that Tysabri caused the injury.'
Any patients exhibiting signs of jaundice or other evidence of liver injury should discontinue Tysabri."