evaluate ustekinumab an anti interleukin il 12 and il 23 antibody effects on radiographic progression in psoriatic arthritis psa 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 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 ustekinumab 45 and 90 mg treatments significantly inhibited radiographic progression of joint damage in patients with active psa.