Effects of ustekinumab on spondylitis-associated endpoints in TNFi-naïve active psoriatic arthritis patients with physician-reported spondylitis: pooled results from two phase 3, randomised, controlled trials

Background The interleukin-12/23p40-subunit-inhibitor ustekinumab significantly improved spondylitis-related symptoms through Week 24 in psoriatic arthritis (PsA) patients with peripheral arthritis and physician-reported spondylitis (PA-PRS) in PSUMMIT-1&2. We further evaluated ustekinumab’s effect on spondylitis-related endpoints in PSUMMIT-1&2 tumour necrosis factor-inhibitor (TNFi)-naïve patients with PA-PRS.Methods Patients with active PsA (≥5 swollen and ≥5 tender joints, C-reactive-protein ≥ 3.0 mg/L) despite conventional (PSUMMIT-1&2) and/or prior TNFi (PSUMMIT-2) therapy received subcutaneous ustekinumab 45 mg, 90 mg or placebo (Week 0, Week 4, Week 16). Changes in Bath Ankylosing Spondylitis Disease Activity Index (BASDAI) neck/back/hip pain question (#2) and modified BASDAI (mBASDAI, excluding PA) scores and Ankylosing Spondylitis Disease Activity Score (ASDAS) responses were assessed at Weeks 12 and 24.Results The pooled PSUMMIT-1&2, TNFi-naïve (n=747), PA-PRS (n=223) subset (158 with human-leucocyte-antigen (HLA)-B27 results) presented with moderate-to-severe spondylitis-related symptoms (mean BASDAI-neck/back/hip pain-6.51, mBASDAI-6.54, BASDAI-6.51, ASDAS-3.81). Mean Week 24 changes were larger among ustekinumab than placebo-treated patients for both neck/back/hip pain (−1.99 vs −0.18) and mBASDAI (−2.09 vs −0.59). Improvements in neck/back/hip pain and fatigue appeared numerically greater in HLA-B27+ than HLA-B27– patients; those for other domains were generally consistent. Greater proportions of ustekinumab versus placebo-treated patients achieved ASDAS clinically important improvement at Week 24 (decrease ≥ 1.1; 49.6% vs 12.7%; nominal p