Original article Clinical endoscopy| Volume 95, ISSUE 3, P500-511.e2, March 2022

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Efficacy and safety of split-dose bowel preparation with 1 L polyethylene glycol and ascorbate compared with 2 L polyethylene glycol and ascorbate in a Korean population: a phase IV, multicenter, randomized, endoscopist-blinded study

Published:October 12, 2021DOI:

      Background and Aims

      The 1-L polyethylene glycol (PEG)-based bowel preparation agent NER1006 (Plenvu; Norgine, Harefield, UK) has shown high cleansing efficacy and tolerability in clinical trials in Europe and North America. However, no clinical trials have yet been reported in Asia. Therefore, the aim of this study was to evaluate the efficacy and safety of 1L PEG-based bowel preparation with Plenvu compared with 2L PEG plus ascorbate bowel preparation in a Korean population.


      In this multicenter, endoscopist-blinded, randomized study, patients at 9 hospitals in South Korea undergoing colonoscopy received either Plenvu or 2L PEG + ascorbate (2L PEG) with a split dose. The primary endpoint was overall bowel cleansing success (Boston Bowel Preparation Scale [BBPS] score ≥2 for all segments of the colon). Secondary endpoints were high-quality bowel cleansing success (overall, BBPS score = 9; segmental colon, BPPS score = 3), polyp detection rate (PDR), and adenoma detection rate (ADR).


      Of 360 included patients, cleansing efficacy was analyzed in 346 (Plenvu, 174; 2L PEG, 172). The Plenvu group showed noninferior bowel cleansing success rates compared with 2L PEG (93.10% vs 91.86%; difference, 1.24%; 1-sided 97.5% lower confidence limit, –4.31%; Pnoninferiority < .0001; Psuperiority = .661). The Plenvu group had higher high-quality bowel cleansing success rates for overall and right-sided colon segments than the 2L PEG group (49.43% vs 37.79% [P = .029] and 60.92% vs 48.84% [P = .024], respectively). The PDR was greater with Plenvu than with 2L PEG (48.85% vs 37.79%, P = .038). However, ADR did not differ between the 2 groups (24.71% vs 20.35%, P = .331). Although treatment-emergent adverse events (TEAEs) were slightly higher in the Plenvu group than in the 2L PEG group (65.71% vs 52.91%, P = .015), most TEAEs were mild (85.55%) and most patients recovered without any management (99.23%).


      Plenvu showed noninferior overall bowel cleansing success rates comparable with 2L PEG but greater high-quality bowel cleansing in overall and right-sided colon, which might help improve the PDR in the Asian population. (Clinical trial registration number: KCT0005894.)

      Graphical abstract


      2L PEG (2 L polyethylene glycol + ascorbate), ADR (adenoma detection rate), BBPS (Boston Bowel Preparation Scale), LCL (lower confidence limit), mITT (modified intention-to-treat), PDR (polyp detection rate), PEG (polyethylene glycol), PP (per-protocol), TEAE (treatment-emergent adverse event)
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