Reviewer ’s report  
 
Title: Comparison of sequential therapy and amoxicillin/tetracycline containing bismuth  
quadruple therapy for the first -line eradication of Helicobact er pylori: a prospective, multi center,  
randomized clinical trial  
 
Version: 0 Date: 11 Feb 2016  
 
Reviewer: Sotirios Georgopoulos  
 
Reviewer's report:  
 
General comments:  
 
This is a prospective, multi -center, randomized, open label trial comparing 10 -day sequential and 
14-day modified (am oxicillin substituted for metronidazole and double daily dosing) quadruple 
regimens. The conclusion was that both regimens were equally ineffective as first line H. pylori 
eradication treatments (eradication rates well below of the cut -off level of 90% in Per Protocol 
analysis).  
 
 
 
Major concerns:  
 
The question raised here is why authors choose a known ineffective regimen in their country (see 
ref. 10) to compare it with an experimental one which in many other previous studies has been 
shown inadequate even in the treatment of amoxicillin or tetracyc line sensitive H. pylori strains 
(see ref. 28), thus leaving in total 66 of their patients not cured from H. pylori. The reasonable 
way would be either to compare the modified regimen with a locally effective regimen (i.e. 
concomitant, hybrid or standard b ismuth -based quadruple) or to undertake a preliminary trial in 
order to examine the effectiveness of the modified regimen in a much lower number of patients 
limiting the number of treatment failures. Authors have to answer this question otherwise their 
study might be considered ethically flawed.  
 
 
Another criticism of this study is that the sample size calculations are based on a rather large 
success rate difference (10%) between regimens that is unusual for a non -inferiority trial. In such 
trials the rate d ifference used is typically below 5% and the 95%CI's are not wide. Here, authors 
used a large rate difference and did not present 95%CI's of that difference. So, I wonder if this 
study has a sufficient power to prove non -inferiority between regimens or it has not enough 
power to prove superiority of SQT versus PBAT.  
 
 
Another limitation of the study is the limited accuracy of 13C -UBT at 4 -6 weeks after the 
completion of a bismuth -based treatment that makes possible, at least in part, a false negative 
diagnosi s of H. pylori eradication leading to an overestimation of success rates with the bismuth -
based regimen (PBAT).  
 
 
In addition, authors should have implemented a multivariate analysis to examine factors that 
might have affected eradication success with either  treatment and especially the experimental 
one, as this treatment is relatively independent from the influence of antibiotic resistance and 
presents (at least in the present study) acceptable compliance rates. Multivariate analysis could 
be useful in revea ling factors negatively affecting eradication rates with this therapy (for 
example patients with ulcer disease versus non - ulcer dyspepsia, not to be stated in this study). 
Finally results should be presented separately center by center in a new table and also included in 
multivariate analysis.  
 
 
 
Minor concerns:  
 
a) In the conclusion should be stated clearly that both regimens are unsatisfactory as first 
line H. pylori eradication treatments (i.e. eliminate that … PBAT could be another 
option…)  
 
b) Extensive lang uage editing is also advised.  
 
 
 
Are the methods appropriate and well described?  
If not, please specify what is required in your comments to the authors.  
 
No 
 
Does the work include the necessary controls?  
If not, please specify which controls are required in yo ur comments to the authors.  
 
Yes 
 
Are the conclusions drawn adequately supported by the data shown?  
If not, please explain in your comments to the authors.  
 
No 
 
Are you able to assess any statistics in the manuscript or would you recommend an  
additional statis tical review?  
If an additional statistical review is recommended, please specify what aspects 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:  
 
Not suitable for publication unless extensively edited  
 
 
 
Declaration of competing interests  
Please complete a declaration of competing interests, conside ring the following questions:  
 
1. Have you in the past five years received reimbursements, fees, funding, or salary from an  
organisation that may in any way gain or lose financially from the publication of this  
manuscript, either now or in the future?  
 
2. Do you hold any stocks or shares in an organisation that may in any way gain or lose  
financially from the publication of this manuscript, either now or in the future?  
 
3. Do you hold or are you currently applying for any patents relating to the content of the  
manuscript?  
 
4. Have you received reimbursements, fees, funding, or salary from an organization that 
holds  or has applied for patents relating to the content of the manuscript?  
 
5. Do you have any other financial competing interests?  
 
6. Do you have any non -financial competing interests in relation to this paper?  
 
 
If you can answer no to all of the above, write 'I declare that I have no competing interests' 
below.  
If your reply is yes to any, please give details below.  
 
I declare that I have no competing interests.  
 
I agree to the open peer review policy of the journal. I understand that my name will be included  
on my report to the authors and, if the manuscript is accepted for publication, my named report  
including any attachments I upload will be posted on the website along with the authors'  
responses. I agree for my report to be made available under an Open Access Creative Commons  
CC-BY license ( http://creativecommons.org/licenses/by/4.0/ ). I understand that any comments  
which I do not wis h to be included in my named report can be included as confidential comments  
to the editors, which will not be published.  
 
I agree to the open peer review policy of the journal  
Reviewer ’s report  
 
Title: Comparison of sequential therapy and amoxicillin/tetracycline containing bismuth  
quadruple therapy for the first -line eradication of Helicobact er pylori: a prospective, multi center,  
randomized clinical trial  
 
Version: 0 Date: 11 Feb 2016  
 
Reviewer: Sotirios Georgopoulos  
 
Reviewer's report:  
 
General comments:  
 
This is a prospective, multi -center, randomized, open label trial comparing 10 -day sequential and 
14-day modified (am oxicillin substituted for metronidazole and double daily dosing) quadruple 
regimens. The conclusion was that both regimens were equally ineffective as first line H. pylori 
eradication treatments (eradication rates well below of the cut -off level of 90% in Per Protocol 
analysis).  
 
 
 
Major concerns:  
 
The question raised here is why authors choose a known ineffective regimen in their country (see 
ref. 10) to compare it with an experimental one which in many other previous studies has been 
shown inadequate even in the treatment of amoxicillin or tetracyc line sensitive H. pylori strains 
(see ref. 28), thus leaving in total 66 of their patients not cured from H. pylori. The reasonable 
way would be either to compare the modified regimen with a locally effective regimen (i.e. 
concomitant, hybrid or standard b ismuth -based quadruple) or to undertake a preliminary trial in 
order to examine the effectiveness of the modified regimen in a much lower number of patients 
limiting the number of treatment failures. Authors have to answer this question otherwise their 
study might be considered ethically flawed.  
 
 
Another criticism of this study is that the sample size calculations are based on a rather large 
success rate difference (10%) between regimens that is unusual for a non -inferiority trial. In such 
trials the rate d ifference used is typically below 5% and the 95%CI's are not wide. Here, authors 
used a large rate difference and did not present 95%CI's of that difference. So, I wonder if this 
study has a sufficient power to prove non -inferiority between regimens or it has not enough 
power to prove superiority of SQT versus PBAT.  
 
 
Another limitation of the study is the limited accuracy of 13C -UBT at 4 -6 weeks after the 
completion of a bismuth -based treatment that makes possible, at least in part, a false negative 
diagnosi s of H. pylori eradication leading to an overestimation of success rates with the bismuth -
based regimen (PBAT).  
 
 
In addition, authors should have implemented a multivariate analysis to examine factors that 
might have affected eradication success with either  treatment and especially the experimental 
one, as this treatment is relatively independent from the influence of antibiotic resistance and 
presents (at least in the present study) acceptable compliance rates. Multivariate analysis could 
be useful in revea ling factors negatively affecting eradication rates with this therapy (for 
example patients with ulcer disease versus non - ulcer dyspepsia, not to be stated in this study). 
Finally results should be presented separately center by center in a new table and also included in 
multivariate analysis.  
 
 
 
Minor concerns:  
 
a) In the conclusion should be stated clearly that both regimens are unsatisfactory as first 
line H. pylori eradication treatments (i.e. eliminate that … PBAT could be another 
option…)  
 
b) Extensive lang uage editing is also advised.  
 
 
 
Are the methods appropriate and well described?  
If not, please specify what is required in your comments to the authors.  
 
No 
 
Does the work include the necessary controls?  
If not, please specify which controls are required in yo ur comments to the authors.  
 
Yes 
 
Are the conclusions drawn adequately supported by the data shown?  
If not, please explain in your comments to the authors.  
 
No 
 
Are you able to assess any statistics in the manuscript or would you recommend an  
additional statis tical review?  
If an additional statistical review is recommended, please specify what aspects 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:  
 
Not suitable for publication unless extensively edited  
 
 
 
Declaration of competing interests  
Please complete a declaration of competing interests, conside ring the following questions:  
 
1. Have you in the past five years received reimbursements, fees, funding, or salary from an  
organisation that may in any way gain or lose financially from the publication of this  
manuscript, either now or in the future?  
 
2. Do you hold any stocks or shares in an organisation that may in any way gain or lose  
financially from the publication of this manuscript, either now or in the future?  
 
3. Do you hold or are you currently applying for any patents relating to the content of the  
manuscript?  
 
4. Have you received reimbursements, fees, funding, or salary from an organization that 
holds  or has applied for patents relating to the content of the manuscript?  
 
5. Do you have any other financial competing interests?  
 
6. Do you have any non -financial competing interests in relation to this paper?  
 
 
If you can answer no to all of the above, write 'I declare that I have no competing interests' 
below.  
If your reply is yes to any, please give details below.  
 
I declare that I have no competing interests.  
 
I agree to the open peer review policy of the journal. I understand that my name will be included  
on my report to the authors and, if the manuscript is accepted for publication, my named report  
including any attachments I upload will be posted on the website along with the authors'  
responses. I agree for my report to be made available under an Open Access Creative Commons  
CC-BY license ( http://creativecommons.org/licenses/by/4.0/ ). I understand that any comments  
which I do not wis h to be included in my named report can be included as confidential comments  
to the editors, which will not be published.  
 
I agree to the open peer review policy of the journal  
Please review this paper.
user
Reviewer ’s report  
 
Title: Comparison of sequential therapy and amoxicillin/tetracycline containing bismuth  
quadruple therapy for the first -line eradication of Helicobact er pylori: a prospective, multi center,  
randomized clinical trial  
 
Version: 0 Date: 11 Feb 2016  
 
Reviewer: Sotirios Georgopoulos  
 
Reviewer's report:  
 
General comments:  
 
This is a prospective, multi -center, randomized, open label trial comparing 10 -day sequential and 
14-day modified (am oxicillin substituted for metronidazole and double daily dosing) quadruple 
regimens. The conclusion was that both regimens were equally ineffective as first line H. pylori 
eradication treatments (eradication rates well below of the cut -off level of 90% in Per Protocol 
analysis).  
 
 
 
Major concerns:  
 
The question raised here is why authors choose a known ineffective regimen in their country (see 
ref. 10) to compare it with an experimental one which in many other previous studies has been 
shown inadequate even in the treatment of amoxicillin or tetracyc line sensitive H. pylori strains 
(see ref. 28), thus leaving in total 66 of their patients not cured from H. pylori. The reasonable 
way would be either to compare the modified regimen with a locally effective regimen (i.e. 
concomitant, hybrid or standard b ismuth -based quadruple) or to undertake a preliminary trial in 
order to examine the effectiveness of the modified regimen in a much lower number of patients 
limiting the number of treatment failures. Authors have to answer this question otherwise their 
study might be considered ethically flawed.  
 
 
Another criticism of this study is that the sample size calculations are based on a rather large 
success rate difference (10%) between regimens that is unusual for a non -inferiority trial. In such 
trials the rate d ifference used is typically below 5% and the 95%CI's are not wide. Here, authors 
used a large rate difference and did not present 95%CI's of that difference. So, I wonder if this 
study has a sufficient power to prove non -inferiority between regimens or it has not enough 
power to prove superiority of SQT versus PBAT.  
 
 
Another limitation of the study is the limited accuracy of 13C -UBT at 4 -6 weeks after the 
completion of a bismuth -based treatment that makes possible, at least in part, a false negative 
diagnosi s of H. pylori eradication leading to an overestimation of success rates with the bismuth -
based regimen (PBAT).  
 
 
In addition, authors should have implemented a multivariate analysis to examine factors that 
might have affected eradication success with either  treatment and especially the experimental 
one, as this treatment is relatively independent from the influence of antibiotic resistance and 
presents (at least in the present study) acceptable compliance rates. Multivariate analysis could 
be useful in revea ling factors negatively affecting eradication rates with this therapy (for 
example patients with ulcer disease versus non - ulcer dyspepsia, not to be stated in this study). 
Finally results should be presented separately center by center in a new table and also included in 
multivariate analysis.  
 
 
 
Minor concerns:  
 
a) In the conclusion should be stated clearly that both regimens are unsatisfactory as first 
line H. pylori eradication treatments (i.e. eliminate that … PBAT could be another 
option…)  
 
b) Extensive lang uage editing is also advised.  
 
 
 
Are the methods appropriate and well described?  
If not, please specify what is required in your comments to the authors.  
 
No 
 
Does the work include the necessary controls?  
If not, please specify which controls are required in yo ur comments to the authors.  
 
Yes 
 
Are the conclusions drawn adequately supported by the data shown?  
If not, please explain in your comments to the authors.  
 
No 
 
Are you able to assess any statistics in the manuscript or would you recommend an  
additional statis tical review?  
If an additional statistical review is recommended, please specify what aspects 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:  
 
Not suitable for publication unless extensively edited  
 
 
 
Declaration of competing interests  
Please complete a declaration of competing interests, conside ring the following questions:  
 
1. Have you in the past five years received reimbursements, fees, funding, or salary from an  
organisation that may in any way gain or lose financially from the publication of this  
manuscript, either now or in the future?  
 
2. Do you hold any stocks or shares in an organisation that may in any way gain or lose  
financially from the publication of this manuscript, either now or in the future?  
 
3. Do you hold or are you currently applying for any patents relating to the content of the  
manuscript?  
 
4. Have you received reimbursements, fees, funding, or salary from an organization that 
holds  or has applied for patents relating to the content of the manuscript?  
 
5. Do you have any other financial competing interests?  
 
6. Do you have any non -financial competing interests in relation to this paper?  
 
 
If you can answer no to all of the above, write 'I declare that I have no competing interests' 
below.  
If your reply is yes to any, please give details below.  
 
I declare that I have no competing interests.  
 
I agree to the open peer review policy of the journal. I understand that my name will be included  
on my report to the authors and, if the manuscript is accepted for publication, my named report  
including any attachments I upload will be posted on the website along with the authors'  
responses. I agree for my report to be made available under an Open Access Creative Commons  
CC-BY license ( http://creativecommons.org/licenses/by/4.0/ ). I understand that any comments  
which I do not wis h to be included in my named report can be included as confidential comments  
to the editors, which will not be published.  
 
I agree to the open peer review policy of the journal  
assistant