Continued improvement of signs and symptoms in ustekinumab-treated patients with active psoriatic arthritis: Week 52 results of a phase 3, multicenter, double-blind, placebo-controlled study

Objectives We report safety & efficacy results through wk52 of PSUMMIT I, a large, multicenter, double-blind, PBO-controlled, Phase 3 trial of ustekinumab (UST) in pts with active psoriatic arthritis (PsA). Methods Adult PsA pts (n=615) with active disease (≥5 SJC and ≥5 TJC; CRP≥0.3mg/dL [ULN 1.0 mg/dL]) despite DMARD and/or NSAID were randomized to UST45mg, 90mg, or PBO at wks 0, 4, and q12w. At wk16, pts with <5% improvement in TJC & SJC entered blinded early escape [EE] (PBO→UST45mg; UST45mg→90mg; 90mg→90mg). Stable concomitant MTX use was permitted but not mandated. Pts treated with prior anti-TNF agents were excluded. PBO pts who did not EE began UST 45mg at wks 24, 28 and q12w. Unlike wk24, available data at wk52 were used for EE pts rather than counting them as nonresponders. AEs are reported through wk52. Results Improvement in clinical, joint, soft tissue, skin, and disability index increased notably from wk24 through wk52 (Table). The proportion of pts with ACR50 at wk24 vs. wk52 were 8.7%/38.0%, 24.9%/31.4%, 27.9%/37.0% for the PBO→UST, UST45mg, UST90mg groups, respectively. ACR responses were still numerically larger among pts not taking MTX at baseline vs. pts taking MTX at baseline. Of pts affected with enthesitis (n=425) or dactylitis (n=286) at baseline, improvements continued beyond wk24, with median percent changes at wk52 of -87.5, -83.3, -74.2 (enthesitis), and -100.00, -100.00, -100.00 (dactylitis) for the PBO→UST, UST45mg, and UST90mg groups, respectively). Mean duration of follow-up through wk52 was 29.75, 50.41, and 50.21wks for the PBO→UST45mg, UST45mg, and UST90mg groups, respectively The proportions of pts with ≥1 AE were 41.3%, 66.8%, and 64.7%, respectively; pts with ≥1 serious AE were 5.3%, 5.9%, and 3.4%; pts with ≥1 serious infection were 0.5%, 1.0%, and 1.0%. No malignancies, TB, opportunistic infections, or deaths occurred through wk52. There were 3 major cardiovascular adverse events reported after the PBO-controlled period in UST-treated pts. Conclusions In pts with active PsA, pts randomized to UST showed markedly reduced signs and symptoms of arthritis, improved physical function, enthesitis, and dactylitis, and alleviation of plaque psoriasis through wk52, at a rate similar to that reported for other biologic treatments through wk52. Safety was consistent with that observed during the PBO-controlled period with limited between-group differences.