Incidence and Predictors of Secondary Failure to Biologic Therapy in Patients With Psoriatic Arthritis

Secondary failure to biologic disease-modifying antirheumatic drugs (bDMARDs) is challenging and contributes to the complexity of managing psoriatic arthritis (PsA). We aimed to define the frequency and incidence of this phenomenon in PsA and identify the risk factors for its occurrence.

We retrieved data on patients with PsA from our single-center, specialized-care, prospective observational cohort who initiated and remained on bDMARDs for ≥ 1 year after clinic enrollment between 2000 and 2023. We defined response to therapy at the 1-year visit (baseline) as achievement of ≥ 40% reduction in the swollen joint count (SJC) and either ≥ 50% reduction in Psoriasis Area and Severity Index (PASI) or PASI ≤ 2. We defined secondary failure as the inability to maintain response criteria or as the clinician's judgment of loss of effectiveness. To examine factors associated with secondary failure, we fitted Cox regression models.

Of 482 patients included in the study, 264 (54.8%) were responders at 1 year. Of these, 94 (35.6%) developed secondary failure at a median of 1.6 (IQR 0.7-3.8) years from response. In the multivariable model, higher SJC (hazard ratio [HR] 1.39, 95% CI 1.05-1.84) and PASI (HR 1.14, 95% CI 1.01-1.29) at baseline were associated with secondary failure. Tumor necrosis factor inhibitors (TNFi) vs other bDMARD use (HR 0.39, 95% CI 0.18-0.88), initiation as first-line bDMARD (HR 0.48, 95% CI 0.25-0.91), and treatment initiation during more recent calendar years (HR 0.34, 95% CI 0.12-0.98) were associated with less secondary failure.

Secondary failure to bDMARD is common in PsA and may be influenced by both disease- and therapy-related factors.