Analysis of Clinical Trial Screen Failures in IBD: Real World Results from the IOIBD

Background: Recruitment rates for phase 2b/3 randomized controlled trials (RCTs) in IBD have substantially dropped over time. Several steps are required prior to successful patient randomization. Initially the physician must propose a trial to a potentially eligible patient during a pre-screening process (step 1). This is followed by patient’s acceptance or refusal (step 2). Finally, after informed consent the patient undergoes trial screening to ensure they meet all eligibility criteria (step 3). Evaluating each step separately, this study aims to assess reasons why IBD patients are not included in RCT and patients’ outcome after screen failure (SF).
Methods: All IOIBD member physicians (n=58) were invited to participate. To assess steps 1 and 2, consecutive IBD patients in relapse for whom a treatment change was required were prospectively included over a 4-week period. Reasons that prevented the IBD physician offering a sponsored multicenter phase 2b/3 RCT (step 1) and reasons why the patient accepted or refused to participate (step 2) were assessed through a physician and a patient survey, respectively. Reasons for SF (step 3) from the last 6 months, including the 4 weeks of steps 1-2, were collected retrospectively.
Results: A total of 104 (59 male, 62 CD, mean age of 37.2 years) and 102 patients (58 male, 63 CD, mean age of 40.6 years) from 12 centers were included in steps 1-2 and 3, respectively (Tables 1 and 2). Among 104 patients in relapse for whom a treatment change was required, 41 (39.4%) were offered a RCT. Of the 28 who consented to RCT, 5 failed their screening (SF rate of 17.9%) and 23 were included. Main reason that prevent IBD physicians from offering an RCT (step 1) are shown in Figure 1. After receiving information about RCT, major reasons why patients accepted or refused to participate included the trust they had in their IBD specialist and the risk of being assigned to a placebo, respectively (step 2). Regarding 102 patients included in step 3, main reasons of SF were insufficient disease activity (n=37), concurrent infection (n=15) and dropout (n=12) (Figure 2). Half of SFs could have been avoided by thorough prescreening. After SF, 51 patients were treated with commercially available therapy, 14 were rescreened for the same RCT (after resolution of the issue leading to SF), no treatment was required for 14, 10 were referred to surgery and 6 were screened for another RCT (the outcome was unknown for 7).
Conclusion: This first multicentric study reported a SF rate of 17.9%. Insufficient disease activity and the risk of assigning the patient to a placebo seem to be barriers to inclusion. Half of SFs could have been avoided by better pre-screening. After SF, most of patients were treated with commercially available therapy.