Screening Failure in a Large Clinical Trial Centre for Inflammatory Bowel Diseases: Rates, Causes, and Outcomes

Patients with inflammatory bowel diseases (IBD) sometimes require investigational medicinal therapy in a clinical trial. Before enrollment, patients must meet strict eligibility criteria, hampering recruitment rates. We investigated the rates, causes, and outcomes of screening failure (SF) in a tertiary IBD center.

We reviewed all IBD patients screened for sponsored multicenter phase 1-3 induction studies with available global SF rates between January 2008 and March 2021. We compared our SF rates with the global SF rates. Causes of SF were categorized into disease activity, hematology, chemistry, microbiology, protocol violation, and withdrawal of consent. Patient outcomes were categorized into rescreening for the same trial, screening for another trial, (re)introduction of commercially available therapy, surgery, or watchful waiting.

During the study period, 642 local screenings were performed as part of 53 studies. We identified an overall SF rate of 17.1%, compared with 39.2% in the global study population (P < .00001). Causes of SF at our center included ineligible disease activity (36.4%), microbiology (25.5%), protocol violation (16.4%), withdrawal of consent (9.1%), chemistry (6.4%) and hematology (6.4%). Thirty SFs could have been avoided by prescreening that was more thorough. After SF, 34 patients were rescreened for the same trial, 17 screened for another trial, 38 initiated approved therapy, 9 were referred for surgery, and 12 did not receive further therapy.

A significant proportion of IBD patients consenting to clinical trials fail their screening. Main causes of SF are ineligible disease activity and abnormal finding on microbiology. Approximately one-fourth of SFs could have been avoided by prescreening that was more thorough.