Early response to therapy predicts 6-month and 1-year disease activity outcomes in psoriatic arthritis patients.

Objectives: In PsA management, remission and low disease activity represent preferential treatment targets. We aimed at evaluating the predictive value and clinical use of initial therapeutic response for subsequent achievement of these targets.

Methods: Based on data of 216 patients enrolled in a randomized controlled trial of golimumab (GO-REVEAL), we performed diagnostic testing analyses using 3- and 6-month disease activity as tests for treatment outcomes to understand the implications of early response. In regression analyses, we estimated the probabilities for achieving at least LDA. Disease activity was measured by the disease activity index for PsA (DAPSA).

Results: Three-month DAPSA levels were excellent tests for disease activity at 6 months (and at 1 year), with areas under the receiver operating characteristic curves of 0.92 (and 0.88, respectively). The estimated probability for 6-month LDA could be quantified as <22% if patients did not reach at least moderate disease activity after 3 months on golimumab. Similar data were seen for early DAPSA response: patients achieving a DAPSA 85% at 3 months had an 84% probability for 6-month LDA or REM. All results were validated in an independent trial cohort of patients treated with infliximab (IMPACT 2).

Conclusion: Three months after implementation of therapy in PsA, it is already possible to evaluate the potential for accomplishing therapeutic goals. This substantiates the choice of the 3-month assessment as essential for treatment adaptations.