INTRODUCTION:Theoretical risks of biologic agents remain under study. OBJECTIVE:The aim of this study was to integrate 1-year safety data from 12 ustekinumab registrational trials. METHODS:Patients had moderate-to-severe plaque psoriasis, active psoriatic arthritis (PsA) (± methotrexate), or moderate-to-severe Crohn's disease (CD; failed/intolerant of immunomodulators/corticosteroids). Psoriatic patients received subcutaneous ustekinumab 45/90 mg or placebo, generally at week 0, week 4, then every 12 weeks thereafter, while those with CD received a single intravenous ustekinumab dose (130 mg or weight range-based dosing of approximately 6 mg/kg) or placebo induction dose at week 0, followed by subcutaneous ustekinumab 90 mg at week 8 and every 8/12 weeks thereafter. The incidence rates of a priori-defined safety events were integrated post hoc (adjusted for duration of follow-up, reported per 100 patient-years [PYs]). RESULTS:Among 6280 enrolled patients, 5884 ustekinumab-treated patients (psoriasis: 3117; PsA: 1018; CD: 1749) contributed 4521 PYs versus 674 PYs in placebo-treated patients through year 1 (829 PYs and 385 PYs during 8- to 16-week controlled periods). Combined across diseases among ustekinumab- versus placebo-treated patients, respective incidences/100 PYs (95% confidence intervals) of infections were 125.4 (122.2-128.7) versus 129.4 (120.9-138.3) through year 1, and not meaningfully increased in patients who did versus those who did not receive methotrexate (92.5 [84.2-101.5] vs. 115.3 [109.9-121.0]), or significantly increased in patients who did versus those who did not receive corticosteroids (116.3 [107.3-125.9] vs. 107.3 [102.0-112.8]) at baseline. Major adverse cardiovascular events (0.5 [0.3-0.7] vs. 0.3 [0.0-1.1]), malignancies (0.4 [0.2-0.6] vs. 0.2 [0.0-0.8]), and deaths (0.1 [0.0-0.3] vs. 0.0 [0.0-0.4]) were rare across indications. CONCLUSIONS:Ustekinumab demonstrated a favorable and consistent safety profile across registrational trials in approved indications. TRIAL REGISTRATIONS:ClinicalTrials.gov identifier: NCT00320216, NCT00267969, NCT00307437, NCT00454584, NCT00267956, NCT01009086, NCT01077362, NCT00265122, NCT00771667, NCT01369329, NCT01369342, and NCT01369355.