Novel 1-L polyethylene glycol + ascorbate versus high-volume polyethylene glycol regimen for colonoscopy cleansing: a multicenter, randomized, phase IV study

BACKGROUND AND AIMS: An adequate bowel cleansing is critical to assure quality and safety of colonoscopy. A novel 1L-PEG plus ascorbate(PEG+ASC) regimen was previously validated against low-volume regimens, but it was never compared with high-volume regimens. METHODS: In a Phase IV study, patients undergoing colonoscopy were randomized 1:1 to receive split-dose 1L PEG+ASC or a split-dose 4L PEG-based regimen in 5 Italian centers. Preparation was assessed with the Boston Bowel Preparation Scale (BBPS) by the local endoscopists and centralized reading, both blinded to the randomization arm. Primary endpoint was noninferiority of 1L PEG+ASC in colon cleansing. Secondary endpoints were superiority of 1L PEG+ASC, patient compliance, segmental colon cleansing, adenoma detection rate (ADR), tolerability and safety. RESULTS: A total of 388 patients (59.8 years) were randomized between January 2019 and October 2019: 195 to 1L PEG+ASC and 193 to 4L-PEG. Noninferiority of 1L PEG+ASC was demonstrated for cleansing in both the whole colon (BBPS>6: 97.9% vs 93%; RR, 1.03; 95% CI, 1.001-1.04; p-superiority=0.027) and in the right colon segment (98.4% vs 96.0%; RR, 1.02; 95% CI, 0.99-1.02; p noninferiority=0.013). Compliance was higher with 1L PEG+ASC than 4L-PEG (178/192, 92.7% vs 154/190 patients, 81.1%; RR, 1.10; 95% CI, 1.05-1.12), whereas no difference was found regarding safety (moderate/severe side-effects: 20.8% vs 25.8%; p=0.253). No difference in ADR (38.8% vs 43.0%) was found. CONCLUSION: 1L PEG+ASC showed noninferiority compared with 4L-PEG in achieving adequate colon cleansing, as well as a higher patient compliance. No differences in tolerability and safety were detected.