Objective Evaluate ustekinumab, an anti-interleukin (IL)-12 and IL-23 antibody, effects on radiographic progression in psoriatic arthritis (PsA).

Methods We conducted preplanned integrated analyses of combined radiographic data from PSUMMIT-1 and PSUMMIT-2 phase 3, randomised, controlled trials. Patients had active PsA despite prior conventional and/or biologic disease-modifying antirheumatic drugs (≥5/66 swollen, ≥5/68 tender joints, C-reactive protein ≥3.0 mg/L, documented plaque psoriasis). Patients (PSUMMIT-1, n=615; PSUMMIT-2, n=312) were randomised to ustekinumab 45 mg, 90 mg, or placebo, at weeks (wk) 0, 4 and every (q) 12 wks. At wk 16, patients with <5% improvement in tender/swollen joint counts entered blinded early escape. All other placebo patients received ustekinumab 45 mg at wk 24 and wk 28, then q 12 wks. Radiographs of hands/feet at wks 0/24/52 were assessed using PsA-modified van der Heijde-Sharp (vdH-S) scores; combined PSUMMIT-1 and PSUMMIT-2 changes in total vdH-S scores from wk 0 to wk 24 comprised the prespecified primary radiographic analysis. Treatment effects were assessed using analysis of variance on van der Waerden normal scores (factors=treatment, baseline methotrexate usage, and study).

Results Integrated data analysis results indicated that ustekinumab-treated patients (regardless of dose) demonstrated significantly less radiographic progression at wk 24 than did placebo recipients (wk 0–24 total vdH-S score mean changes: 0.4-combined/individual ustekinumab dose groups, 1.0-placebo; all p<0.02). From wk 24 to wk 52, inhibition of radiographic progression was maintained for ustekinumab-treated patients, and progression was substantially reduced among initial placebo recipients who started ustekinumab at wk 16 or wk 24 (wk 24 – wk 52, total vdH-S score mean change: 0.08).

Conclusions Ustekinumab 45 and 90 mg treatments significantly inhibited radiographic progression of joint damage in patients with active PsA.