Residual Disease Activity in Psoriatic Arthritis Patients Treated with Secukinumab and Adalimumab Who Achieved Remission or Low Disease Activity: Results from a Phase 3b, Randomized, Double-blinded, Active-controlled, Head-to-head Study

Background/Purpose: Recent EULAR recommendations propose that treatment of psoriatic arthritis (PsA) should seek remission (REM) or alternatively low disease activity (LDA) by regular disease activity assessments using composite indices targeting one or several key manifestations in PsA.1,2 The EXCEED study compared secukinumab (SEC) and adalimumab (ADA) monotherapy in patients with active PsA with inadequate response/intolerance to csDMARDs. We present a post hoc analysis of patients who achieved LDA and/or REM at Week 24 and 52 with their respective levels of residual disease activity (RDA) in the core components of the various composite indices. Methods: Head-to-head, phase-3b, randomized, double-blind trial: biologic naive active PsA patients were randomized to receive SEC 300 mg subcutaneous at baseline, Week 1-4, and then every 4wks (q4w) until Week 48 or ADA 40 mg subcutaneous at baseline and then q2w until Week 50. The primary and key secondary endpoints at Week 52 were previously reported.3 LDA and REM were assessed using MDA, VLDA, DAPSA REM/LDA and PASDAS REM/ LDA. The proportions of RDA were established for clinical domains of PsA (articular, enthesitis, and psoriasis), HAQ, VAS pain, patient global assessment (PtGA) and Physician’s global assessment (PhGA) of disease activity. The composite indices were analyzed using logistic regression and missing data was handled using multiple imputation. RDA levels are presented in patients who achieved either LDA and/or REM. Results: A similar proportion of patients receiving SEC and ADA achieved LDA and REM at Week 24. Further increase from Week 24 in LDA/REM was observed in both treatment groups through Week 52. VLDA was achieved by a lower proportion of patients than PASDAS LDA+REM/REM and DAPSA LDA+REM/REM at Week 24 and 52 (Table 1). The proportion of patients achieving VLDA, PASDAS REM and DAPSA REM in the treatment groups at Week 24 had low RDA (10%-19%) across core components except for PhGA and PASI ≤1 (Table 2). At least 66%, 59% and 49% of the patients achieving MDA, PASDAS LDA+REM and DAPSA LDA+REM, respectively, across both treatment groups had no RDA at Week 24 suggesting that MDA was the most stringent composite index. Further decrease in RDA was observed among patients who achieved either REM or LDA at Week 52 across all composite indices in both treatment groups (Table 2 and 3). Conclusion: A comparable proportion of patients achieved LDA and/or REM at Week 24 across the two treatment groups with further improvements in response/targets at Week 52. Patients who achieved VLDA or MDA tended to have a lower residual disease activity than those who achieved PASDAS REM/LDA+REM or DAPSA REM/LDA+REM. Residual disease activity was lower in patients reaching REM than LDA and somewhat lower in patients who achieved VLDA than PASDAS REM or DAPSA REM.