To compare the effectiveness, safety and costs of standard versus individually tailored reduced doses of recombinant human tumor necrosis factor receptor-Ig fusion protein for injection (rhTNFR:Fc) in patients with ankylosing spondylitis (AS) after achieving low disease activity.

This was a single center prospective observational study performed within Renji Hospital. The etanercept biosimiliar (Qiangke) tapering strategy was chosen by treating physicians, without pre-specified protocol. We used pro-pensity score (PS) methodology to identify 2 cohorts of patients matched for relevant baseline characteristics including age, gender, baseline activity, baseline function, disease duration, duration of anti-tumor necrosis factor (TNF) therapy. Multiple clinical indexes including Bath ankylosing spondyliti diseases activity index (BASDAI) and Bath ankylosing spondylitis functional index (BASFI), C reactive protein (CRP) at baseline and every follow up visits and costs of rhTNFR:Fc drugs were compared between both PS-matched cohorts. T test, Mann-Whitney U test, chi-square test were used for statistical analysis.

One hundred and twenty-seven consecutive AS patients were included who were treated with either reduced (n=72) or standard (n=55) doses of TNF inhibitors. The mean change per 1 year in BASFI, as well as BASDAI and CRP of every visit was not different between both groups, but the cost for anti-TNF drugs was substantially lower in the reduced dosing group [(47 328±5 695) ￥/year vs (84 864±569) ￥/year, t=0.015, P<0.05]. The number of patients with flares was similar in both groups [29% (21/72) vs 21.8% (12/55), χ²=0.88, P=0.347].

The strategy to reduce doses of rhTNFR:Fc produce similar clinical outcomes at 1 year in AS patients after reaching low disease activity, but is substantially less costly.

Spondylitis, ankylosing; Comparative effectiveness research; Clinical protocols