This is a longitudinal, observational, prospective, multicentre study conducted in France, among a representative sample of rheumatology doctors.

The aim of this study is to describe in real life the therapeutic strategy when faced with a patient with rheumatoid arthritis (RA) or psoriatic arthritis (PsA) who requires initiation of treatment with biotherapy or targeted therapy. The evolution of the disease and the possible therapeutic adaptations will then be followed for 2 years.

Inclusion Criteria:

• Major patient (age ≥ 18 years)
• Patient with RA according to American College of Rheumatology (ACR) / European Congress of Rheumatology (EULAR) 2010 or ACR 1987 or patient with PsA according to ClASsification criteria for Psoriatic ARthritis (CASPAR) criteria
• Patient undergoing treatment with methotrexate (MTX) (oral or injectable) initiated for at least 3 months.
• Naïve patient of biotherapy or tsDMARD and requiring the introduction of a first bDMARD or tsDMARD due to the activity of the disease.
• Patient informed and accepting the computer processing of his/her medical data and informed of his/her rights of access and rectification.

Exclusion Criteria:

• Patient participating in an interventional study in rheumatology
• Patient with axial spondyloarthritis (for patients with PsA)

RA or PsA patient undergoing treatment with MTX for at least 3 months and requiring the introduction of a first bDMARD or tsDMARD due to the activity of the disease will be asked to participate from bDMARD or tsDMARD treatment introduction (inclusion visit) up to 24 months after inclusion.