DOI: 10.25934/pr00007549
title: Responsiveness of the UC-100 Score in Patients with Moderately to Severely Active Ulcerative Colitis

description: Ulcerative colitis (UC) is a disease that causes swelling and pain, most commonly in the large bowel and rectum which are located at the end of the digestive tract (the tube that carries food and its byproducts through the body),closest to the anus. Diarrhea and feces with blood in it are frequent symptoms. While there is no cure for UC, there are several approved drugs to help control the symptoms. Unfortunately, no one drug works in all patients and even when a drug does work, it may become less effective over time. Therefore, there is a need for other drugs that work and that are safe to use.

To learn whether a new drug works to treat UC, it must be tested in research studies. One way to do this is to compare the drug to a placebo, which is a “fake”copy of the real drug. The placebo looks like the real drug, but it contains none of the medicine. In such a study, some UC patients are given drug while others are given placebo. Usually this is decided randomly (like the flip of a coin) and neither the patients nor their doctors know what they are taking until the study is over. If a drug works, the group treated with the real drug should do better (have less disease activity) than the group that received the placebo. But how is this measured? In studies for UC, disease activity is often measured using the Mayo Clinic Score (MCS) (Schroeder et al., 1987), but other measures, including the partial MCS (pMCS), adapted MCS, and Robarts Histopathology Index (RHI) also exist. The ability of a measure to detect a difference, when one exists, between the effect of a drug as compared to placebo is referred to as “sensitivity”. A more sensitive measure makes it easier to tell if a drug is working than a less sensitive measure does. It could also mean that fewer participants will be needed for a research study before we can tell if a drug is working, and this could, in turn,reduce the cost of drug development.

Early research results suggest that a measure of UC disease activity called the UC-100 (Jairath et al., 2019)is more sensitive than the MCS or other existing measures. The goal of the current study is to confirm whether this is true. To do this, we will use existing data from previous drug studies in UC and compare the ability of different measures to detect changes in disease activity. If this study finds that the UC-100 is a more sensitive measure of UC disease activity than other measures across several research study datasets, this could change the way we conduct future research studies in UC. With greater sensitivity, it could be possible to detect even small effects of a drug that might be missed with less sensitive measures. This might make it less likely for a potentially effective drug to be mistakenly labeled as a failure during the early drug development process. The ultimate aim is to get better at identifying when a drug is working in the hopes that this will lead to the approval of more safe and effective drugs for UC and provide a larger number of treatment options for patients whose disease is not adequately controlled by currently available drugs.