Comparison of Different Remission Indices in Patients with Psoriatic Arthritis: A Post Hoc Analysis of Data from Phase 3 Tofacitinib Studies

Abstract

Background: An international task force has agreed that remission and low disease activity (LDA) are treatment targets for patients (pts) with PsA, and recommends the Disease Activity Index in Psoriatic Arthritis (DAPSA) and minimal disease activity (MDA) to assess disease activity states.1 Tofacitinib is an oral Janus kinase inhibitor for the treatment of PsA. Objectives: In this post hoc analysis, we compared DAPSA LDA with MDA, and DAPSA remission with very low disease activity (VLDA) and DAS28-3(CRP) remission, in pts with PsA receiving tofacitinib. Methods: Data were pooled from 2 Phase 3 studies (OPAL Broaden [12 months; NCT01877668]; OPAL Beyond [6 months; NCT01882439]) for pts receiving tofacitinib 5 or 10 mg twice daily (BID) or placebo (PBO). DAPSA was determined by summing: swollen joint count (SJC66); tender/painful joint count (TJC68); Patient’s Global Assessment of Arthritis (PtGA; visual analogue scale [VAS]); pain (VAS); and CRP. Pts were classified as achieving MDA or VLDA when meeting ≥5 (MDA) or 7 (VLDA) of the following criteria: TJC68 ≤1; SJC66 ≤1; Psoriasis Activity and Severity Index ≤1 or body surface area ≤3%; pain (VAS) ≤15; PtGA (VAS) ≤20; HAQ-DI ≤0.5; tender entheseal points (using Leeds Enthesitis Index [LEI]) ≤1. A logistic regression model was used to assess demographic and baseline characteristics as predictors of a trend in DAPSA scores at Month (M)3. DAPSA LDA (≤14), MDA, DAPSA remission (DAPSA ≤4), VLDA and DAS28-3(CRP) remission (DAS28-3[CRP]<2.6) rates were compared at M1, M3 and M6 for pts receiving tofacitinib 5 mg BID and at M6 for pts receiving tofacitinib 5 or 10 mg BID. Agreement between disease activity indices at M6 was evaluated using a kappa test. The percentage of tofacitinib-treated pts who achieved MDA, VLDA and non-response was reported at M6, stratified by achievement of DAPSA LDA, remission or non-response. Results: This analysis included 709 pts: tofacitinib 5mg BID, n=237; tofacitinib 10mg BID, n=236; PBO, n=236. At M3, older patients treated with tofacitinib, and tofacitinib- or PBO-treated pts with higher baseline SJC66, TJC68, PtGA VAS, HAQ-DI, LEI and Pain VAS, were significantly (p<0.05) more likely to have higher DAPSA. DAPSA LDA, MDA, remission (DAPSA and DAS28-3[CRP]) and VLDA rates generally increased from M1 to M6 for patients receiving tofacitinib 5mg BID (Figure a). At M6, most tofacitinib-treated pts who achieved MDA, and all who achieved VLDA, were also in DAPSA remission or LDA (Figure b). At least moderate agreement (defined by kappa values 0.41–0.60) was observed between DAPSA LDA and MDA, and between DAPSA remission and VLDA, with both doses of tofacitinib at M6 (Figure c). Conclusion: Remission and LDA rates generally increased over time in pts with PsA receiving tofacitinib. DAPSA LDA showed moderate agreement with MDA, and DAPSA remission showed at least moderate agreement with VLDA, confirming that DAPSA and MDA are useful measurement tools to assess disease activity in pts with PsA treated with tofacitinib.