Drug levels, immunogenicity and assessment of active sacroiliitis in patients with axial spondyloarthritis under biologic tapering strategy.

The aim of the study was to assess drug levels, immunogenicity and sacroiliitis on MRI in patients with axial spondyloarthritis under biologic tapering strategy. Consecutive patients with axial spondyloarthritis who remained in low disease activity more than 1 year after dose tapering of infliximab and adalimumab were included. Plasma drug concentrations of TNF inhibitors and anti-drug antibodies were determined, and MRI of sacroiliac joints was evaluated. Of twenty patients included, eighteen had therapeutic drug levels, no patient had anti-drug antibodies, and no patient had active sacroiliitis on MRI. These data could support the biologic tapering strategy and their maintenance over time.