We switched 87 patients who were in a clinical state of stability from oETA to bETA: 48 patients were affected by Rheumatoid Arthritis (RA),26 by Psoriatic Arthritis (PsA) and 13 by Ankylosing Spondylitis (AS).We evaluated VAS-pain, Global-Health, CRP, number of swollen and tender joints, Disease Activity Score on 28 joints (DAS28) for RA, Disease Activity in Psoriatic Arthritis (DAPSA) for PsA, Health Assessment Questionnaire (HAQ) and Health Assessment Questionnaire for the spondyloarthropathies (HAQ-S),Bath Ankylosing Spondylitis Disease Activity Index (BASDAI) for AS patients. Here, CRP is linked to ankylosing spondylitis.