RANDOMIZED CONTROLLED TRIAL COMPARING THE BOWEL CLEANSING EFFICACY OF NOVEL 1 LITRE POLYETHYLENE GLYCOL+ASCORBATE NER1006 VERSUS HIGH-VOLUME POLYETHYLENE GLYCOL USING A SPLIT DOSING REGIMEN

Aims Efficacy and acceptability of bowel preparations are relevant for accuracy and patient-experience of colonoscopy. A novel1L-PEG+Ascorbate(PEG+A)solution has been successfully validated against low-volume regimens only. This multicenter-randomized-trial compared the efficacy, acceptability,tolerability,and safety of the 1L-PEG-A ner1006 versus a high-volume PEGregimen, both as split-dose regimens (NCT03742232).

Methods 399 patients referred for screening,surveillance or diagnostic colonoscopy were randomly assigned to receive either ner1006 or4L-PEG in 5 endoscopy centers in Italy. Endoscopists blinded to the preparation assessed level of cleansing using the BostonBowelPreparationScale(BBPS). A centralized review of colonoscopy videos and BBPSevaluation was also performed by an independent group of expert endoscopists blinded to the preparation modality. Acceptability and patient compliance were assessed using a questionnaire for self-reported patient-experience. Level of cleansing, acceptability and patient compliance were compared between the two groups through odds ratios calculated from univariate logistic regressions. Blood tests monitoring renal function and electrolytes were performed one week before colonoscopy and at the time of the procedure.

Results 374/399 enrolled patients(male:47.6%; median age: 60 years) were included in the analysis.Of these, 188 (50.3%) were assigned to ner1006 and 186 to 4L-PEG, and the cecal intubation rate was 100% (188/188) and 97.3% (183/186), respectively (p=0.122). The overall BBPSscore was greater with ner1006 than with 4L-PEG, with a mean of 8.3 (95%CI:8.1-8.5) versus (7.7;95%CI:7.5-7.9;p< 0.01), resulting in an OR of 2.51 (95%CI:1.31-4.81;p=0.005).Concordance between local and centralized review was 98.9%.Self-reported moderate to severe discomfort (OR:0.88;95% CI:0.58-1.32; p=0.536), nausea (OR:1.47;95%CI:0.93-2.33;p=0.097),cramps/pain (OR:0.91; 95%CI:0.51-1.61, p=0.736) and bloating (OR:0.93,95%CI:0.57-1.51,p=0.759) did not differ between study arms.The percentage of patients who would not repeat the preparation in the future (22.7%vs.32.2%) was lower with ner1006 than 4L PEG (OR:0.62;95%CI:0.39-0.98;p=0.041). Treatment compliance was higher with ner1006 than with 4L PEG (93.0% vs 81.4%; OR:2.31; 95%CI:1.14-4.93; p=0.024). No statistically significant changes were recorded in blood tests between the two groups (mean Na⁺143.7 ner1006 vs 141.4 4L; K⁺4.6vs4.4;Cl^-140.0 vs 140.7; p>0.05 for all).

Conclusions The novel 1L-PEG-Abowel preparation ner1006 is more effective and better tolerated than the high-volume4L-PEG, supporting its use in clinical practice. No serious adverse events have been observed in the study population. Blood tests have shown that both the preparations used in this trial are not associated to significant shift of ions or modifications of renal functions.