POS1049 EFFECT OF FILGOTINIB ON PASDAS: DRIVERS OF LOW AND VERY LOW ACTIVITY UP TO WEEK 100

Abstract

Background:EQUATOR (NCT03101670) was a Phase 2, double-blind, randomised placebo (PBO)- controlled trial of the preferential Janus kinase 1 inhibitor filgotinib (FIL) for the treatment of psoriatic arthritis (PsA); EQUATOR2 (NCT03320876) is the open-label extension (OLE).Objectives:This post-hoc analysis assessed the effect of FIL on individual Psoriatic Arthritis Disease Activity Score (PASDAS) components; and the association between PASDAS disease activity (DA) levels and DA levels achieved for each PASDAS component and patient-reported outcomes (PROs) up to OLE Week (Wk) 100.Methods:In EQUATOR, patients with active moderate-to-severe PsA were randomised 1:1 to oral FIL 200 mg or PBO once daily (QD) for 16 wks.1 At Wk 16, patients could continue into the 304-wk OLE, in which all patients received FIL 200 mg QD. The proportions of patients with PASDAS of very low DA (VLDA; ≤1.9), LDA (>1.9–<3.2), moderate DA (MoDA; ≥3.2–<5.4), and high DA (HDA; ≥5.4) at core Wk 16 and OLE Wk 52 and 100 were assessed. The proportion with improved PASDAS status vs baseline (BL) at OLE Wk 52 and 100 was calculated. Percent change from BL in PASDAS components and PROs were assessed at core Wk 16 and OLE Wk 52 and 100 by PASDAS status (VLDA, LDA, other). Multivariate logistic regression analyses performed cross-sectionally identified PASDAS components and PROs associated with not achieving VLDA or LDA at core Wk 16 and OLE Wk 52 and 100; all analyses were observed cases.Results:At OLE Wk 52, LDA and VLDA were achieved by 27.5% and 16.8% of randomised patients, respectively (44.3% combined). At OLE Wk 100, LDA and VLDA were achieved by 26.0% and 17.6% of patients (43.6% combined; Figure 1). Of patients with HDA at BL, 69% improved to MoDA/LDA/VLDA, <4% remained in HDA and 27% did not reach Wk 100; of those in MoDA at BL, 63% improved to VLDA/LDA, 11% remained stable, <4% worsened and 22% did not reach Wk 100. Patient Global Assessment of Disease Activity (PtGDA), Short Form-36 physical component scale (SF-36 PCS), Functional Assessment of Chronic Illness Therapy, and Health Assessment Questionnaire Disability Index were found to be important components/PRO measures in achieving VLDA vs LDA (Table 1). Logistic regression indicated that factors associated with not achieving LDA at Wk 52 were PtGDA (odds ratio [OR]: 1.20, 95% confidence interval [CI]: 1.07–1.35), physician GDA (PhGDA; OR: 1.58, 95% CI: 1.18–2.12), and SF-36 PCS (OR: 0.79, 95% CI: 0.67–0.95); PtGDA was associated with not achieving VLDA (OR: 1.30, 95% CI: 1.15–1.47).Conclusion:The proportion of patients achieving PASDAS VLDA or LDA increased over time and remained stable between OLE Wk 52 and 100. Important factors in determining whether VLDA/LDA was met were PtGDA, PhGDA, and SF-36 PCS, although the low patient numbers is a limitation.