Brief report: enhancement of patient recruitment in rheumatoid arthritis clinical trials using a multi-biomarker disease activity score as an inclusion criterion.

ABSTRACT

OBJECTIVE: Rheumatoid arthritis (RA) clinical trials often exclude patients who have low C-reactive protein (CRP) levels, which slows enrollment into the trial. The purpose of this study was to determine whether high Multi-Biomarker Disease Activity (MBDA) scores (>44) in RA patients with low CRP levels (≤10 mg/liter) could be used as a complement to CRP levels >10 mg/liter to enhance patient recruitment without affecting clinical trial outcomes. METHODS: We evaluated patients from the Swedish Pharmacotherapy (SWEFOT) trial, which did not include any selection criteria for CRP levels. Clinical outcomes were assessed after 3 months of methotrexate (MTX) monotherapy in MTX-naive RA patients (n = 220) and after 3-10 months of add-on therapy in patients who were incomplete responders to MTX alone (MTX-IR) (n = 127). Radiographic outcomes were assessed at 1 year in all patients. Within each cohort, the outcomes were compared between patients with a CRP level of ≤10 mg/liter and an MBDA score of >44 at the start of the respective treatment interval versus those with a CRP level of >10 mg/liter. RESULTS: Patients with both a CRP level of ≤10 mg/liter and an MBDA score of >44 at baseline had clinical and radiographic outcomes that were comparable to those in patients with a CRP level of >10 mg/liter at baseline. This broadened definition of the inclusion criteria identified an additional 24% of patients in the MTX-naive cohort and 47% in the MTX-IR cohort. CONCLUSION: Patient recruitment into RA clinical trials may be substantially enhanced, without any decrease in clinical and radiographic outcomes, by using as an inclusion criterion "a CRP level of >10 mg/liter and/or an MBDA score of >44."