I det andet aktivt kontrollerede forsøg var andelen af alvorlige bivirkninger efter 2 års behandling den samme i de tre behandlingsgrupper (Enbrel 16%, methotrexat 15% og Enbrel i kombination med methotrexat 17%).
In the first active-controlled trial, serious adverse events occurred at a frequency of 6% in 415 patients treated with Enbrel compared with 8% of 217 methotrexate-treated patients.