P276 Comparative effects of ixekizumab (IXE) vs adalimumab (ADA) across PsA patients defined by baseline characteristics: week 24 outcomes from SPIRIT-H2H

Abstract

Background: Ixekizumab (IXE), an IL‐17A antagonist, showed superi‐ority over TNF‐inhibitor adalimumab (ADA) for the simultaneous achieve‐ment of ACR50 and PASI100, and PASI100 alone in the SPIRIT‐H2H trial at week24. We analysed differences in efficacy outcomes between IXE and ADA by subgroups. Methods: We conducted post‐hoc analysis of data from SPIRIT‐H2H (NCT03151551), a 52‐week, multicentre, open‐label, blinded assessor study patients with active PsA (defined as swollen joint count ≥3 and tender joint count ≥3), with a body surface area [BSA] ≥3% and insuffi‐cient response to ≥1 conventional synthetic disease‐modifying anti‐rheu‐matic drugs (csDMARDs) and naïve to biologic (b)‐DMARDs. Patients were randomised 1:1 to IXE or ADA, while presence/absence of moder‐ate‐to‐severe psoriasis (defined as PASI ≥12, static Physician Global As‐sessment ≥3 and BSA ≥10%) determined on‐label dosing. Subgroups were defined by baseline enthesitis, dactylitis, fingernail psoriasis (pres‐ence/absence), BSA ( <10%, ≥10%) and CRP (≤6mg/L, >6mg/L). A Fisher's exact test was used for between group comparisons of efficacy outcome measures at 24weeks (PASI90, ACR50/70, and minimal dis‐ease activity [MDA]). Missing data were overcome by non‐responder im‐putation. Nine pts with active PsO and BSA≥3% were assessed as PASI = 0 at baseline, a medical inconsistency that was resolved using medical judgement. These patients were considered PASI100 responders if PASI = 0 and BSA = 0 at post baseline visits. Results: At week24 IXE and ADA demonstrated comparable efficacy in ACR50 response rates across all subgroups. ACR70 response in pa‐tients with fingernail psoriasis was significantly greater with IXE‐treated vs ADA (p = 0.02). PASI90 response with baseline enthesitis (p <0.001), without dactylitis (p <0.001), with fingernail psoriasis (p <0.001), CRP (≤6mg/L, p = 0.003; >6mg/L, p = 0.036) and BSA ( <10%, p = 0.010; ≥10%, p = 0.003) was significantly greater in IXE vs ADA. Significantly more IXE‐treated patients vs ADA achieved MDA with baseline enthesi‐tis (p = 0.002), without dactylitis (p = 0.015), with fingernail psoriasis (p <0.001), CRP ≤6mg/L (p = 0.046) and BSA ≥10% (p = 0.01). A limitation is that this analysis was completed post‐hoc, not controlled for multiplic‐ity, and patients were not stratified by baseline disease characteristics. Conclusions: IXE and ADA are associated with comparable efficacy and associated with a greater effect in certain subgroups. Results will aid clinicians when making treatment choices.