Consensus definitions of complex-to-manage and treatment-refractory psoriatic arthritis: a GRAPPA initiative

Despite advances in the treatment of psoriatic arthritis (PsA), a substantial proportion of patients continue to report persistent symptoms and impaired quality of life. However, terminology remains inconsistent for patients who fail to achieve disease control despite treatment, which limits research comparability and contributes to therapeutic inertia. To address this gap, a Group for Research and Assessment of Psoriasis and Psoriatic Arthritis (GRAPPA) task force developed consensus definitions for two distinct states: complex-to-manage PsA (C2M-PsA) and treatment-refractory PsA (TR-PsA). C2M-PsA is defined as a state of persistent symptoms despite treatment with at least one biologic or targeted synthetic DMARD (b/tsDMARD), extending beyond biological non-response to include factors such as comorbidities, overlapping conditions, psychosocial burden and treatment-related challenges (for example, non-adherence). TR-PsA, a more specific subset of C2M-PsA, is characterized by failure of at least three therapies with distinct mechanisms of action (including at least two biologic/targeted synthetic DMARDs), persistent symptoms considered problematic by both patient and clinician, and objective evidence of ongoing inflammation - after ruling out alternative explanations for treatment refractoriness. These consensus-derived GRAPPA definitions provide a shared framework to standardize terminology, support individualized care, and improve patient stratification in research and practice. Prospective validation across diverse settings and phenotypes is needed to confirm their reliability, responsiveness and clinical utility.