Alternative Endoscopy Reading Paradigms Determine Score Reliability and Effect Size in Ulcerative Colitis.

Objective: Central reading of endoscopy is advocated by regulatory agencies for clinical trials in ulcerative colitis [UC]. It is uncertain whether the local/site reader should be included in the reading paradigm. We explore whether using locally- and centrally-determined endoscopic Mayo subscores [eMS] provide a reliable final assessment and whether the paradigm used has an impact on effect size.

Methods: eMS data from the TURANDOT [NCT01620255] study were used to retrospectively examine seven different reading paradigms (using the scores of local readers [LR], first central readers [CR1], second central readers [CR2], and various consensus reads [ConCR]) by assessing inter-rater reliabilities and their impact on the key study endpoint, endoscopic improvement.

Results: More than 40% of eMS scores between two trained central readers were discordant. Central readers had wide variability in scorings at baseline (intraclass correlation coefficient [ICC] of 0.475 [0.339, 0.610] for CR1 vs CR2). Centrally-read scores had variable concordance with LR (LR vs CR1 ICC 0.682 [0.575, 0.788], and LR vs CR2 ICC 0.526 [0.399, 0.653]). Reading paradigms with LR and CR which included a consensus, enhanced ICC estimates to >0.8. At Week 12, without the consensus reads, the CR1 vs CR2 ICC estimates were 0.775 [0.710, 0.841], and with consensus reads the ICC estimates were >0.9. Consensus-based approaches were most favourable to detect a treatment difference.

Conclusion: The ICC between the eMS of two trained and experienced central readers is unexpectedly low, which reinforces that currently used central reading processes are still associated with several weaknesses.