Review for 10.1186/s12876-019-0988-y (2019)

Reviewer ’s report  
 
Title: Novel 1L polyethylene glycol -based bowel preparation (NER1006): proof of concept 
assessment versus standard 2L polyethylene glycol with ascorbate - a randomized parallel group 
Phase 2 colonoscopist -blinded trial  
 
Version: 0 Date: 09 Nov 2018  
 
Reviewer: Fabrizio Parente  
 
Reviewer's report:  
 
From the gastroenterologist's perspective the concept of optimal bowel cleansing prior to 
colonoscopy is for a preparation to be well tolerated, s afe and effective, allowing a complete 
visualization of the bowel mucosa in order to detect all possible mucosal lesions. In this regard, 
patient adherence to the bowel cleansing regimen is vital. From the patient's perspective, bowel 
preparation needs abo ve all to be well tolerated to be an effective product. Indeed, poor tolerance 
of the bowel cleansing regimen can negatively impact adherence, leading to a reduction in 
efficacy.  
The rate of poor colonoscopy preparation in most prospective studies is usual ly reported between 
15 and 30% among patients using the PEG -based solution. Prior studies have demonstrated that 
2 litres PEG split -based bowel preparations are as effective as 4 litres split -based bowel 
preparation but much better tolerated expecially by elderly people who have already problems 
with fluid intake. In this connection, the development of new effective bowel preparation at 
lower liquid volume may further increase patients' compliance to colonoscopy.  
 Aim of the present study was twofold: first , an initial study in order to explore, among four new 
test formulations based on  PEG + Asc., the two products most suitable for further clinical 
investigation; second, to evaluate, in an endoscopist -blinded trial, the efficacy of the two selected 
variant  preparations, compared to the control 2L PEG + Asc. regimen, in patients undergoing 
screening colonoscopy, by evaluating the mean 24 -hour stool weight and the bowel cleansing 
success (Harefield Cleansing Scale).  
The article is interesting and well writte n, since describes the modalities of development of the 
new 1L PEG+Asc acid compound, recently launched on the pharmaceutical market by Norgine 
Ltd;  however, I think it is most suitable to a pharmacological rather than a gastroenterological 
journal.  
  
Minor comments:  
The manuscript contains too much Tables and Figures, which can be easily condensed into 3 -4 
pages at most.  
Are the methods appropriate and well described?  
If not, please  specify what is required in your comments to the authors.  
 
Yes 
 
Does the work include the necessary controls?  
If not, please specify which controls are required in your comments to the authors.  
 
Yes 
 
Are the conclusions drawn adequately supported by the data s hown?  
If not, please explain in your comments to the authors.  
 
Yes 
 
Are you able to assess any statistics in the manuscript or would you recommend an  
additional statistical review?  
If an additional statistical review is recommended, please specify what aspec ts require further  
assessment in your comments to the editors.  
 
I am able to assess the statistics  
 
Quality of written English  
Please indicate the quality of language in the manuscript:  
 
Acceptable  
 
Declaration of competing interests  
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5. Do you have any other financial competing interests?  
 
6. Do you have any non -financial competing interests in relation to this paper?  
 
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below.  If your reply is yes to any, please give details below.  
 
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