To evaluate the efficacy and safety of ustekinumab through 2 years in adult patients with active psoriatic arthritis (PsA).
A total of 615 adult patients with active PsA were randomized to placebo, ustekinumab 45 mg, or ustekinumab 90 mg, at weeks 0, 4, and every 12 weeks through week 88 (last dose). At week 16, patients with <5% improvement in both tender and swollen joint counts entered blinded early escape (placebo to 45 mg, 45 mg to 90 mg, and 90 mg to 90 mg). All remaining placebo patients crossed over to ustekinumab 45 mg at week 24. Clinical efficacy measures included American College of Rheumatology criteria for 20% improvement (ACR20), Disease Activity Score in 28 joints using the C-reactive protein level (DAS28-CRP), and ≥75% improvement in the Psoriasis Area and Severity Index (PASI75). Radiographic progression was evaluated using the modified Sharp/van der Heijde score (SHS).
At week 100, ACR20, DAS28-CRP moderate/good response, and PASI75 rates ranged from 56.7-63.6%, 71.9-76.7%, and 63.9-72.5%, respectively, across the 3 treatment groups. In both ustekinumab groups, the median percent improvement in dactylitis and enthesitis was 100% at week 100. The mean changes in SHS score from week 52 to week 100 were similar to those observed from week 0 to week 52 in the ustekinumab groups. Through week 108, 70.7% and 9.7% of patients had an adverse event (AE) or serious AE, respectively. The rates and type of AEs were similar between the dose groups.
Clinical and radiographic benefits from ustekinumab treatment were maintained through week 100 in the PSUMMIT 1 study. No unexpected safety events were observed; the safety profile of ustekinumab in this population was similar to that previously observed in psoriasis patients treated with ustekinumab.