AB0801 EFFECTS OF GUSELKUMAB, A MONOCLONAL ANTIBODY THAT SPECIFICALLY BINDS TO THE P19-SUBUNIT OF INTERLEUKIN-23, ON DACTYLITIS AND ENTHESITIS IN PATIENTS WITH ACTIVE PSORIATIC ARTHRITIS: POOLED RESULTS THROUGH WEEK 24 FROM TWO PHASE 3 STUDIES

Abstract

Background:Guselkumab (GUS), a novel monoclonal antibody that specifically binds to the p19-subunit of IL-23, demonstrated efficacy in the Ph 3 DISCOVER-1 (D1) & DISCOVER-2 (D2) trials of pts with active psoriatic arthritis (PsA).1,2Dactylitis & enthesitis, key PsA clinical manifestations, can be difficult to treat and may portend more significant disease burden.3,4Objectives:In pts with dactylitis or enthesitis at baseline, assess: 1) changes in symptoms over time and 2) relationships between improvements in dactylitis or enthesitis and other PsA domains.Methods:Adults with active PsA despite standard therapies were eligible for D1 & D2. Approx. 30% of D1 pts previously received 1-2 TNF inhibitors; D2 pts were biologic-naïve. Pts were randomized 1:1:1 to GUS 100mg Q4W; GUS 100mg at W0, W4, Q8W; or PBO. Independent assessors evaluated dactylitis (total score: 0-60) & enthesitis (Leeds Enthesitis Index [LEI]; total score 0-6). Dactylitis and enthesitis findings through W24 were prespecified to be pooled across D1 & D2. P-values are unadjusted. We assessed changes in dactylitis and LEI scores over time (ANCOVA); associations between dactylitis or enthesitis resolution and ACR/PASI responses at W24 (Chi-square); and correlations between dactylitis or LEI and HAQ-DI/SF-36 change scores at W24 (Spearman’s correlation). AEs through W24 were reported.1,2Results:At W0, 42% of pooled D1+D2 pts had dactylitis; 65% had enthesitis. GUS improved dactylitis and LEI scores vs PBO at W8, W16, W24. GUS vs PBO differences were significant for dactylitis changes at W16 & W24 and LEI changes at W8 (Q4W only), W16 & W24; no dose response was observed (Fig). Rates of dactylitis or enthesitis resolution by W24 were consistently significantly (p<0.001) associated with ACR20/50/70 and PASI75/90 response (Table). In GUS-treated pts at W24, significant correlations were observed between dactylitis change scores and PASI (p<0.001 Q4W; p=0.006 Q8W) and SF-36 MCS (p=0.038 Q4W; p=0.003 Q8W) changes, and between LEI and HAQ-DI change scores (p<0.001 Q4W; p=0.005 Q8W). No consistent correlations/associations were observed between dactylitis or LEI scores and other clinical outcomes.Conclusion:In PsA pts with dactylitis or enthesitis at W0, GUS improved dactylitis or LEI scores vs PBO by W8; treatment differences were significant at W16 & W24. Resolution of dactylitis or enthesitis was significantly associated with clinically meaningful improvements in PsA joint & skin symptoms. Improved dactylitis scores correlated with improved skin symptoms and mental health; improved LEI scores correlated with improved physical function.