Biogen Idec Adds Liver Warning To Multiple Sclerosis Therapy Avonex

Interferon beta product joins Serono/Pfizer's Rebif with warning reflecting postmarketing experiences. Berlex' Betaseron does not have a warning but recommends testing. Coming on the heels of the Tysabri withdrawal, the labeling change is the second recent setback for Biogen Idec's multiple sclerosis franchise.