Continue or Withdraw Biologic Therapy in Non-Radiographic Spondyloarthritis Patients?
Non-radiographic spondyloarthritis is an illness that needs a little explaining. Ankylosing spondylitis (AS) is an inflammatory spinal disease that is defined by findings on x rays (sacroiliitis, for example). Once individuals have these x-ray changes, they have already experienced damage to these skeletal structures. These changes do not occur overnight, but progress gradually in the affected joints. These inflammatory changes can be identified by magnetic resonance imagining studies that reveal the presence of joint inflammation before the changes noted on x ray occur. Therefore, this illness is pre-radiographic because changes on x ray are not visible.
Questions remain with regard to the nature of pre-radiographic spondyloarthritis. Is pre-radiographic disease just the beginning phases of AS? Or Is pre-radiographic spondyloarthritis a different illness that may start and stop by its own parameters, not those associated with AS?
In a study of non-radiographic spondyloarthritis and Humira (adalimumab), 305 of 673 enrolled patients were able to achieve a remission of their illness by 28 weeks. Parameters of improvement included decrease in measurement of fatigue, morning stiffness, tenderness, and pain in non-spinal joints. At 28 weeks, 152 continued on Humira, and 153 received placebo. Forty weeks later, the number of arthritis flares were calculated for both groups. The individuals who remained on Humira had a flare rate of 30 %. The flare rate for the placebo group was 53%. More adverse events, mostly nasopharyngitis, occurred in the Humira treated group.
The conclusion of the authors is that remaining on Humira for inflammatory arthritis of the spine is a better choice than stopping therapy. The results of this study do not tell us if AS and non-radiographic spondyloarthritis is the same or different illnesses.
Reference: Landewe R et al. Efficacy and safety of continuing versus withdrawing adalimumab therapy in maintaining remission in patients with non-radiographic axial spondyloarthritis (ABILITY-3) a multicenter, randomized, double-blind study. Lancet 2018;392:134-44