medwireNews: Real-world study results suggest that mild tapering of tumor necrosis factor (TNF) inhibitors does not influence the probability of achieving inactive disease among patients with axial spondyloarthritis (axSpA).
However, Eun Young Lee (Seoul National University College of Medicine, South Korea) and co-researchers caution that heavy dose tapering was associated with a significantly reduced likelihood of achieving this outcome.
The longitudinal study included 776 patients from the Korean College of Rheumatology Biologics Registry (KOBIO) cohort who started TNF inhibitor treatment between 2013 and 2017, and had been receiving these agents for at least 1 year at the time of study entry. Lee and team classified each 1-year follow-up interval from all patients as an observational unit, and the study included 1575 intervals in total.
As reported in Arthritis Research & Therapy, 27.9% of intervals were categorized as mild dose tapering – defined as a dose quotient (DQ) of 50–90% – while 2.8% were classed as heavy tapering (DQ<50%), and 69.3% formed the no taper control group (DQ=100%). DQ was calculated from the average actual dose and dosing interval relative to the standard dose and dosing interval.
The researchers note that all patients treated with subcutaneous TNF inhibitors, ie, etanercept, adalimumab, and golimumab, tapered their treatment by increasing the dosing interval, while those given intravenous infliximab either reduced the infusion dose (68.2%) or prolonged the interval (38.1%). Decisions to taper treatment were made by patients and physicians.
Lee et al found that patients in the mild tapering group had a comparable likelihood of achieving ASDAS inactive disease, defined as an ASDAS-CRP score of less than 1.3 points, to those who did not taper their TNF inhibitor, at rates of 46.3% versus 41.2%. On the other hand, they say that the probability of achieving this outcome was “markedly lower” in the heavy tapering group, at 29.5%.
These findings translated into a significant 73% lower likelihood of achieving ASDAS inactive disease with heavy tapering versus no tapering in a longitudinal multivariable model.
In contrast to these findings, there was no significant difference in the probability of achieving at least a 50% improvement in BASDAI score among patients in either the mild or heavy tapering group compared with those in the reference group, at rates of 75.7%, 72.7%, and 77.8%.
The study authors hypothesize that the discrepancy between the ASDAS and BASDAI50 findings could be explained by differences in control of inflammation between the control and heavy tapering groups, because ASDAS measures “put more weight on inflammation than BASDAI.”
They point out that, overall, the likelihood of achieving ASDAS inactive disease was “relatively low,” which “suggests that non-selective application of TNF [inhibitor] tapering in patients receiving TNF [inhibitor] treatment for more than 1 year is not appropriate to reach the optimal goal.”
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