Agreement between local and central reading of endoscopic disease activity in ulcerative colitis: results from the tofacitinib OCTAVE trials

BACKGROUND: Endoscopy is routine in trials of ulcerative colitis therapies. AIM: To investigate agreement between central and local Mayo endoscopic subscore (MES) reads in the OCTAVE programme METHODS: Flexible sigmoidoscopy was performed in tofacitinib induction (OCTAVE Induction 1&2, NCT01465763 and NCT01458951), maintenance (OCTAVE Sustain, NCT01458574) and open‐label, long‐term extension (OCTAVE Open, NCT01470612) studies. Kappa statistics and Bowker's tests evaluated agreement/disagreement between centrally and locally read MES, with potential determinants of differences analysed by logistic regression. RESULTS: Moderate‐to‐substantial agreement was observed between central and local reads at screening (77.1% agreement; kappa 0.62 [95% confidence interval 0.59‐0.66]), OCTAVE Induction 1&2 week (Wk) 8 (63.8%; 0.62 [0.59‐0.66]), OCTAVE Sustain Wk 52 (55.6%; 0.56 [0.50‐0.62]) and for induction non‐responders at OCTAVE Open month 2 (59.9%; 0.54 [0.48‐0.60]). Where disagreements occurred, local reads were systematically lower than central reads at OCTAVE Induction 1&2 Wk 8, OCTAVE Sustain Wk 52 and OCTAVE Open month 2 (Bowker's P < 0.0001); this difference was not observed at screening (P = 0.0852). Using multivariable logistic regression, geographical region, C‐reactive protein (Wk 8), partial Mayo score (Wk 8) and prior tumour necrosis factor antagonist failure were associated with disparity at OCTAVE Induction 1&2 Wk 8 (P < 0.05). In OCTAVE Induction 1&2 and OCTAVE Sustain, significantly higher proportions of patients endoscopic improvement, remission and endoscopic remission with tofacitinib vs placebo, using either central or local reads. CONCLUSION: Moderate‐to‐substantial agreement was observed between central and local endoscopic reads. Where disagreements occurred, local reads were systematically lower than central reads at most timepoints, suggesting potential bias. ClinicalTrials.gov identifier: NCT01465763, NCT01458951, NCT01458574, NCT01470612.