Objectives: The Disease Activity Index in Psoriatic Arthritis (DAPSA) and psoriatic arthritis (PsA) minimal disease activity (MDA) are recommended to assess remission and low disease activity (LDA).1 Tofacitinib is an oral JAK inhibitor for the treatment of PsA. We compared DAPSA LDA with MDA, and DAPSA remission with very low disease activity (VLDA) and DAS28-3(CRP) remission, in patients with PsA receiving tofacitinib.

Methods: Data were pooled post hoc from two Phase 3 studies (OPAL Broaden [NCT01877668]; OPAL Beyond [NCT01882439]) for patients receiving tofacitinib 5 (n=237) or 10mg (n=236) twice daily (BID) or placebo (n=236). DAPSA was determined by summing: swollen joint count (SJC66); tender/painful joint count (TJC68); Patient Global Assessment of Arthritis (PtGA; visual analog scale [VAS]); patient-assessed pain (VAS); and CRP. MDA or VLDA was defined as ≥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; Leeds Enthesitis Index ≤1. Logistic regression modelled demographic and baseline characteristics as predictors of DAPSA scores at Month (M)3. DAPSA LDA (≤14), MDA, DAPSA remission (≤4), VLDA, and DAS28-3(CRP) remission (<2.6) rates were compared at M1, M3, and M6 for tofacitinib 5mg BID, and at M6 for tofacitinib 5/10mg BID. A Kappa test evaluated agreement between disease activity indices at M6. The percentage of tofacitinib-treated patients achieving MDA and VLDA at M6 was stratified by achievement of DAPSA LDA or remission.

Results: Older patients receiving tofacitinib, and tofacitinib- or placebo-treated patients with higher baseline SJC66, TJC68, PtGA VAS, HAQ-DI, LEI and Pain VAS, were significantly (p<0.05) more likely to have higher DAPSA at M3. DAPSA LDA/remission, MDA, DAS28-3(CRP) remission, and VLDA rates generally increased from M1 to M6 in both tofacitinib dose groups. At M6, most tofacitinib-treated patients with MDA, and all with VLDA, were also in DAPSA remission or LDA. There was ≥moderate agreement (defined as Kappa values 0.41−0.60) between DAPSA LDA/remission and MDA, and DAPSA remission and VLDA.

Conclusion: Remission and LDA rates generally increased over time in patients with PsA receiving tofacitinib. DAPSA LDA and remission showed ≥moderate agreement with MDA and VLDA, respectively. DAPSA and MDA are useful tools to measure PsA disease activity.