A Study of Clinical and Immune Responses to Sequential Biologic Therapies in Psoriatic Arthritis

The goal of this observational study is to evaluate how well advanced therapies work in adults with psoriatic arthritis (PsA) who are starting a biologic or targeted synthetic disease-modifying antirheumatic drug (b/tsDMARD) as part of routine care. The main questions are: * Do treatment responses differ according to the number of previous advanced therapies? * Can anti-drug antibodies (ADAs) or blood drug levels help predict treatment effectiveness? Researchers will compare participants receiving earlier-line versus later-line advanced therapies to assess differences in treatment response and antibody development. Participants will allow collection of routine clinical assessment data, complete questionnaires on symptoms and quality of life, and provide blood samples before treatment and at 12 weeks.

NCT Number	NCT07417995
Lead Sponsor	Royal United Hospitals Bath NHS Foundation Trust Collaborators: University of Bath
Conditions	Psoriasis Arthritis
Enrollment	400 participants
Start Date	2026-06
Primary Completion	2027-06 (estimated)
Study Completion	2027-06 (estimated)
Updated on ClinicalTrials.gov	2026-05-13