CRP and ulcerative colitis: Key secondary outcomes include (1) clinical response, a continuous measure of the sum of Mayo rectal bleeding and stool frequency sub-scores summarized as the mean at day 3; (2) C-reactive protein (CRP), a continuous measure summarized as the mean at day 3; and (3) endoscopic response, a continuous measure defined by the Ulcerative Colitis Endoscopic Index of Severity (UCEIS) summarized as the mean at day 5.