Effectiveness of adalimumab and secukinumab with and without concomitant csDMARD in psoriatic arthritis patients: retrospective cohort study

Abstract Background To compare the effectiveness of biologic disease-modifying antirheumatic drugs (bDMARDs) with and without concomitant conventional synthetic DMARDs (csDMARDs) in terms of bDMARD drug retention in psoriatic arthritis (PsA) patients. Methods PsA patients starting first-line bDMARD adalimumab and/or second-line bDMARD secukinumab between November 2019 and March 2025 were included and categorized as bDMARD monotherapy or as combination therapy (bDMARD with concomitant csDMARD). Patients ineligible for combination therapy (csDMARD contraindications or side effects) were excluded. bDMARD discontinuation due to side effects or ineffectiveness was counted as an event. Individual patients could contribute data to both adalimumab and secukinumab analyses. Primary outcome was bDMARD drug retention, analyzed using Kaplan-Meier curves and multivariable Cox regression adjusted for age and sex. Results 635 PsA patients were included: 183 adalimumab monotherapy and 318 combination therapy; 136 secukinumab monotherapy and 125 combination therapy. The csDMARDs in the combination therapy were mostly methotrexate (65–67%) or leflunomide (21–30%). Adalimumab combination therapy showed significantly lower discontinuation risk in unadjusted (median retention 11.0 vs 15.0 months, hazard risk 0.71, p = 0.012) and adjusted analyses (adjusted hazard risk 0.67, p = 0.003) compared to adalimumab monotherapy. In secukinumab, no significant difference was observed for monotherapy versus combination therapy (median retention 10.6 vs 7.3 months, hazard risk 1.11, p = 0.50 and adjusted hazard risk 1.14, p = 0.42). The effect of csDMARD use was significantly greater in adalimumab compared to secukinumab (interaction: p = 0.028). Conclusion Concomitant csDMARD use significantly prolonged drug retention for adalimumab but not for secukinumab, suggesting csDMARDs should be continued when starting adalimumab but may be discontinued when starting secukinumab.