I den første undersøgelse af recidiverende MS var procentdelen af de patienter, hvis invaliditet var forværret ved afslutningen af to år, 22% hos de Avonex- behandlede patienter og 35% hos de placebobehandlede patienter.
In the first study, 22% of the patients with relapsing MS who were treated with Avonex and 35% of the patients treated with placebo had a worsening of disability by the end of two years.