A Study to Evaluate the Efficacy and Safety of Ustekinumab in the Treatment of Anti-TNFα Naive Participants With Active Radiographic Axial Spondyloarthritis

A Phase 3, Multicenter, Randomized, Double-blind, Placebo-controlled Study Evaluating the Efficacy and Safety of Ustekinumab in the Treatment of Anti-TNF Alpha Naive Subjects With Active Radiographic Axial Spondyloarthritis

The purpose of this study is to assess the efficacy of ustekinumab, in adult participants with active radiographic axial spondyloarthritis (AxSpA), who are naive to anti-TNF alpha agents, as measured by the reduction in signs and symptoms of radiographic AxSpA.

This is a Phase 3, multicenter (when more than one hospital or medical school team work on a medical research study), randomized (study medication assigned to participants by chance), double-blind (neither the researchers nor the participants know what treatment the participant is receiving), placebo-controlled (an inactive substance; a pretend treatment [with no drug in it] that is compared in a clinical trial with a drug to test if the drug has a real effect) study. The study consists of 3 phases; Screening (up to 8 weeks), Treatment phase: placebo-controlled (Week 0 to 24) and active treatment (Week 24 to Week 100), and Safety Follow-up (12 weeks after last dose). Participants will be randomly assigned to 1 of 3 treatment groups: placebo, ustekinumab 45 mg and ustekinumab 90 mg. The total duration of study will be up to 112 weeks. Participants will be primarily assessed for Assessment of SpondyloArthritis International Society (ASAS) 40 response at Week 24. Participants' safety will be monitored throughout the trial.

Inclusion Criteria:

• Participants must have a diagnosis of definite ankylosing spondylitis (AS), as defined by the modified 1984 New York criteria. The radiographic criterion must be confirmed by a central xray reader and at least 1 clinical criterion must be met
• Participants must have symptoms of active disease at screening and at baseline, as evidenced by both a BASDAI score of greater than or equal to (>=4) and a visual analog scale (VAS) score for total back pain of >=4, each on a scale of 0 to 10
• Participants with elevated high sensitivity C-reactive protein (hsCRP) level of >=0.300 milligram per deciliter (mg/dL) at Screening
• If using nonsteroidal anti-inflammatory drugs (NSAIDs) or other analgesics for AS, must be on a stable dose for at least 2 weeks prior to the first administration of study agent. If currently not using NSAIDs or other analgesics for AS, must not have received NSAIDs or other analgesics for AS for at least 2 weeks prior to the first administration of the study agent
• A woman of childbearing potential must have a negative serum (beta-human chorionic gonadotropin [beta-hCG]) at screening and a negative urine pregnancy test at Week 0 before randomization

Exclusion Criteria:

• Participants who have other inflammatory diseases that might confound the evaluations of benefit from the ustekinumab therapy, including but not limited to, rheumatoid arthritis, systemic lupus erythematosus, or Lyme disease
• Participants who are pregnant, nursing, or planning a pregnancy or fathering a child while enrolled in the study or within 5 months after receiving the last administration of study agent
• Participants who have received any prior biologic therapy, including but not limited to anti-TNF alpha agents, tocilizumab, alefacept, efalizumab, natalizumab, abatacept, anakinra, ustekinumab, tidrakizumab or other anti-interleukin (IL) 23 biologics, brodalumab, secukinumab, ixekizumab, and B-cell depleting therapies
• Participants who have received any systemic immunosuppressives or disease-modifying antirheumatic drugs (DMARDs) other than methotrexate (MTX), sulfasalazine (SSZ), or hydroxychloroquine (HCQ) within 4 weeks prior to first administration of study agent. Medications in these categories include, but are not limited to chloroquine, azathioprine, cyclosporine, mycophenolate mofetil, gold, and penicillamine
• Participant who have received leflunomide within 3 months prior to the first administration of study agent (irrespective of undergoing a drug elimination procedure), or have received leflunomide within 12 months prior to the first administration of study agent and have not undergone a drug elimination procedure