IL23A and rheumatoid arthritis: In contrast, IL-12/IL-23p40 subunit inhibition failed to show clinical benefit in multiple sclerosis, and IL-12/IL-23p40 or IL-23p19 subunit-targeted therapy failed to improve clinical outcomes in studies of patients with active rheumatoid arthritis, despite strong scientific rationale for this approach derived from animal models (31, 45, 108, 110).