In stage 1, two doses (high and low) of LY3471851 will be compared to placebo. In stage 2, up to two additional doses (to be confirmed) of LY3471851 will be compared to placebo.~LY3471851 (NKTR-358) is a potential first-in-class therapeutic that may address an underlying immune system imbalance in people with many autoimmune conditions. It targets the interleukin (IL-2) receptor complex in the body in order to stimulate proliferation of inhibitory immune cells known as regulatory T cells. By activating these cells, LY3471851 may act to bring the immune system back into balance.
The reason for this study is to determine if the study drug LY3471851 is safe and effective in adult participants with active ulcerative colitis (UC). The study will last about 52 weeks.