Optimized Bismuth Quadruple Therapy vs Triple Standard Therapy for Helicobacter Pylori Eradication: Clinical Efficacy Randomized Trial
Phase: PHASE4
Conditions: Helicobacter Pylori Infection
Sponsor: Pontificia Universidad Catolica de Chile

Study protocol and Statistical Analysis Plan 
 
 
 
Optimized bismuth quadruple therapy vs 
triple standard therapy for Helicobacter 
pylori eradication: 
Clinical efficacy randomized trial. 
 
 
 
NCT: Not yet assigned 
2022-11-10 

  
Optimized bismuth quadruple therapy vs triple standard 
therapy for Helicobacter pylori eradication: Clinical efficacy 
randomized trial. 
Introduction 
Background and rationale 
Helicobacter pylori 
Helicobacter pylori (H. pylori) is a Gram (-) and micro aerophilic bacterium that is uniquely adapted to 
infect the luminary surface of the gastric epithelium.  Although an innate and adaptive immune response 
to infection is elicited by the host, it is insufficient for bacterial eradication.   Therefore, a chronic infection  
is developed  and can persist for decades if no treatment is performed (1).   
H. pylori was first identified by Warren and Marshall in 1982.  At the time the scientific community 
doubted any bacteria could survive he acid of the stomach. Marshall ingested the bacterial culture, 
showing symptoms of the infection. Administration of antibiotics resolved those symptoms fulfilling 
Koch's postulates, thus demonstrating the pathogenic role of H. pylori in peptic ulcer (1). 
H. pylori survives the adverse conditions of the stomach by converting urea to ammonium and carbon 
dioxide changing local pH. In addition, its helical shape and flagellum helps  penetrate the mucous layer 
allowing  it to evade the acidic pH of the gastric lumen (1). 
H. pylori Infection Epidemiology 
H. pylori infection is asymptomatic in most of its carriers; however, a proportion of people will develop:  
1. Duodenal or gastric ulcers (1.0% to 10.0%). 
2. Gastric cancer (0.1% to 3.0%). 
3. MALT (mucosa-associated lymphoid tissue) lymphoma (<0.01%). 
H. pylori infection  is considered to be one of the main risk factors for the development of gastric 
adenocarcinoma. For this reason, the International Agency for Research on Cancer (IARC) classified it as a 
human carcinogen type 1 (2). 

The prevalence of H. pylori worldwide is estimated to be 48.5%. However, the infection geographical 
distribution is heterogeneous. Developed countries such as Switzerland (18.9%), Denmark (22.1%), New 
Zealand (24.0%), Australia (24.6%) and Sweden (26.2%) have low prevalence, close to 20.0% while  a a 
prevalence exceeding 80.0%, in countries such as Nigeria (87.7%), Portugal (86.4%), Estonia (82.5%)) and 
Pakistan (81.0% ) have been described  (3)." 
Latin America has a high burden of H. pylori infection  and its associated outcomes., particularly gastric 
cancer (4).  In Chile,  Ferreccio et. al., showed that according to the 2003 National Health Survey the 
prevalence of H. pylori infection was 73.0% (95%CI: 70.0%-76.0%). Maximum values were found between 
in the 45 to 64 years old group with a decrease at older ages. In addition, men were significantly more 
infected (5).  Considering the reports published in the decade of 2000-2010, Chile has one of the highest 
prevalences worldwide and within Latin America, reaching more than 70.0% (3). 
During 2020, In Chile gastric cancer was the second leading cause of cancer deaths (second in men and 
fourth  in women) (6). From 1985 to 2002, gastric cancer mortality rate was 19.2 per 100,000 population 
(7). The incidence and mortality rate of gastric cancer has remained unchanged over the past 20 years, 
despite strategies developed to try to reduce its incidence. In addition, the Chilean Ministry of Health 
estimated in 2013,  34,700 Years of Potential Lost years of life due to the infection (8).  In parallel, 
GLOBOCAN reports that there has been an increase in the incidence of stomach cancer in people under 
50 years of age in Chile (9). 
Role of H. pylori eradication in Public Health 
Successful eradication of H pylori has been shown to prevent its associated outcomes,  including gastric 
cancer, with an RR of 0.6 (95% CI: 0.4-0.9) with a relative decrease in risk of 40.0%   when comparing those 
eradicated versus non-eradicated (4, 10). 
The preventive effect of eradication has better performance when used in patients who have not 
developed cancer yet but show early preneoplastic histological alterations giving the chance to the gastric 
mucosa to return to normal after eradication (10). Therefore, the Maastricht consensus  recommends 
addressing H pylori infection with a preventive approach of testing and treating1 in people with dyspepsia 
without diagnosis, especially in those areas with high prevalence of infection (10).  The Taipei consensus  
makes its recommendations along the same lines, recommending the strategy of testing and treating 
young adults  who belong to populations with a high incidence of gastric cancer, before atrophic gastritis 
 
1 It involves testing for H. pylori through a non-invasive method in patients with dyspepsia and performing 
eradication therapy in those patients positive to the infection. 

and intestinal metaplasia  develop (11).  A recent study in the Matsu Islands where this type of strategy 
was implemented showed a decrease in H. pylori infection rates from 64.2% to 15.0%, with reinfection 
rates lower than 1% per person-year. During the 1995 to 2003 period, the effectiveness of this 
intervention strategy reduced the incidence of gastric cancer to 53.0% (95% CI: 30% to 69%) (12). 
Eradication schemes and their effectiveness 
Currently, in Chile, patients with  peptic ulcer disease and  H. pylori infection are beneficiaries of free 
eradication through the Explicit Health Guarantees program. 2 The clinical practice guidelines for 
Helicobacter pylori eradication therapy in patient with peptic ulcer disease recommends as first-line 
therapy: 
1. A standard dose of proton pump inhibitor, every 12 hours 
2. Clarithromycin, 500 mg every 12 hours orally. 
3. Amoxicillin 1 gr every 12 hours orally.  Metronidazole 500 mg is used every 12 hours in case of 
penicillin allergy. 
This scheme constitutes the standard triple therapy (OAC triple therapy), and is administered for 14 days 
(14). This eradication scheme has been widely recommended as a primary therapy in populations with  
low CLA resistance, with expected success rates of 80.0% to 85.0% (10).  This therapeutic scheme 
effectiveness is supported in Latin America by a study demonstrating 82.2% (95% CI = 78.5%-85.5%) of 
eradication when compared  with concomitant 5-day therapy and 10 days sequential therapy schemes 
(15).. 
In Latin America, a multicenter trial of 1463 participants from Chile, Colombia, Costa Rica, Honduras, 
Nicaragua and Mexico reported an eradication rate for triple therapy of 82.2% in post-treatment control 
which dropped to 80.4% at the one year follow-up , which is on the verge of the accepted therapeutical 
efficacy limits (>80%) (4). 
The effectiveness of the OAC scheme has shown a clear downward trend, with eradication rates falling 
below 80.0% in intention-to-treat analyses. An increase in antibiotic resistance (4), the limited amount of 
 
2 In agreement with the MEDICAL AND ADMINISTRATIVE TECHNICAL STANDARDS FOR COMPLIANCE WITH THE 
EXPLICIT HEALTH GUARANTEES OF LAW 19.966. The inclusion criteria for Eradication treatment is all people with 
Helicobacter pylori positive plus any of the following conditions: to be over 40 years of age, to have confirmed gastric 
or duodenal ulcer, MALT lymphoma, atrophic gastritis, first-degree relatives with a history of gastric cancer, having 
gastric resection for gastric cancer, dysfunctional dyspepsia 13. 
MINSAL. APPROVED STANDARDS OF A 
MEDICAL AND ADMINISTRATIVE TECHNICAL NATURE FOR COMPLIANCE WITH THE EXPLICIT HEALTH GUARANTEES 
OF LAW 19,966. In: PUBLIC SDS, editor. 2013.. 

antibiotics that have shown effectiveness for H. pylori treatment and the extensive use of some of them 
in other infectious diseases ( clarithromycin use in respiratory infections) are mostly to blame  (16). 
Antibiotic resistance mechanisms of are mostly chromosome encoded mutations, changes in the bacterial 
physiology leading to decrease in the entry and increase on excretion of these of antibiotics or from the 
bacteria, and the creation of biofilms or cocoid-like bacterial colonies.  Through these mechanisms, H. 
pylori strains can manifest three antibiotic resistance profiles: single antibiotic resistance, multi-
resistance, and hetero-resistance (16). 
Another variable identified as a barrier in the effectiveness of eradication therapy is the influence of 
polymorphisms on CYP2C19 cytochrome.  These polymorphisms affect the metabolization of most PPIs. 
resulting in several haplotypes of metabolizers (homozygous and heterozygous rapid metabolizers or slow 
metabolizers).   Rapid metabolizers show a decreased effect on PPIs effectiveness, so a limited increase in 
pH is observed. This can drastically decrease the effectiveness of the eradication therapy, since is a  pH 
between 6 and 7  is necessary for antibiotics  optimal effect (17, 18).  
In this scenario, international guidelines for the management of H. pylori infection  recommend avoiding 
the use of clarithromycin and levofloxacin as first-line therapy when H. pylori strains resistance rates  in 
any given population is over 15%  (19).  Recent studies in Chile report clarithromycin resistance rates up 
to 26% (20) and 27% (21). For this reason, the use of clarithromycin in Chile as a first-line therapy should 
be avoided. 
in Latin America, studies show low prevalence of resistance ( 4% (95%CI: 2-8%) for amoxicillin  (22). On 
the contrary high resistance rates for metronidazole have been described 53% (95% CI: 46-60%).  
Regardless of the fact its use continues since resistance to metronidazole can be overcome with the 
prolongation of therapy, increasing the dose of the antibiotic or using it concomitantly with bismuth (22)." 
Relevance of H. pylori eradication therapy schemes analysis in Chile:  Study 
Justification  
The high prevalence of H. pylori infection in the Chilean population justifies the need for an eradication 
program that is practical, low-cost and effective.  
The latest consensus for the Management of H. pylori in Latin America establishes that quadruple therapy 
between 10 and 14 days should be studied in the region because it can be a good alternative for the 
eradication of H. pylori as a first or second line therapy in areas with high prevalence of resistance to 
clarithromycin and metronidazole as it is the case in Chile  (4, 20-22). The Toronto Consensus for the 

Treatment of H. pylori Infection  in Adults agrees on this point, recommending quadruple bismuth therapy 
as first-line therapy and that the duration of the treatment be 14 days (19).  
in Chile a recent study Reyes et  al.  analyzed eradication and adverse event rates of the most commonly 
used H. pylori eradication schemes in a retrospective cohort design, based on clinical records of patients 
treated at 2 health centers in Santiago de Chile  (23).   The study reports an eradication rate of 97.62% 
for quadruple bismuth therapy, versus 81.95% for standard triple therapy.  Despite its promising results, 
the study has limitations:  drug use for each of the therapies was heterogeneous and according to 
attending physician criteria. Success of H. pylori eradication was also defined by the attending physician.  
Regardless, this study supports the hypothesis that in Chile the use of quadruple bismuth therapy may be 
the most effective option for the successful eradication of H. pylori in its population.  
This study proposes a randomized, multicenter, controlled, double-blind clinical trial with two parallel 
groups with the aim of generating the best possible quality of evidence to justify the use of quadruple 
bismuth therapy in Chile, and confirm the promising results of the retrospective cohort of Reyes et.al.  
(23).  
Research Question and Hypothesis 
Research Question: Is the quadruple therapy with bismuth better than the Standard triple therapy used in 
Chile for the eradication of Helicobacter pylori in Chilean patients?  
Hypothesis: The use of an optimized quadruple therapy with bismuth (intervention) compared to standard 
triple therapy will increase the rate of H. pylori eradication from 80.0% to 95.0% in infected Chilean 
population 
Methods 
AIMS 
Primary aim 
To compare the H. pylori eradication rate between the quadruple bismuth therapy versus the standard 
triple therapy recommended by the AUGE Clinical Guidelines for Helicobacter pylori eradication treatment 
in peptic ulcer patients. 

Secondary – exploratory aims 
To determine the incidence of Adverse Drug Reactions (ADRs) and the therapeutic adherence to 
quadruple bismuth therapy versus the standard triple therapy recommended by the AUGE Clinical 
Guidelines for Helicobacter pylori eradication treatment in peptic ulcer patients. 
To determine any possible additional factors such as sociodemographic variables, comorbidities, infection 
with resistant strains and polymorphism of CYP2C19 that may increase or decrease the probability of 
success of the  eradication therapies under study in this particular population setting 
Studio Design 
Randomized, multicenter, controlled, double-blind clinical trial with two parallel arms.  The control group 
will receive the current Standard Triple Therapy for the eradication of H. pylori. It consists in omeprazole 
+ amoxicillin + clarithromycin for 14 days.  The intervention group will be administered Quadruple Therapy 
with Bismuth, that consists in esomeprazole + amoxicillin + metronidazole + bismuth subsalicylate for 14 
days. Details can be found in Table 1. 
The proposal follows the CONSORT methodology and criteria for randomized, prospective double-blind 
clinical studies and will be enrolled in www.clinicaltrials.gov. 
Inclusion and exclusion criteria for participants 
Inclusion Criteria: 
1. Age between 18-75 years 
2. Diagnosed with H. pylori infection 3 
a. By positive Urease test. 
Exclusion criteria: 
1. Pregnant or lactating women. 
2. Allergy or history of adverse reaction to the following medications: 
a. Penicillin 
b. Salicylate allergy4 
c. Omeprazole 
3. Has received H. pylori eradication therapy prior to the study. 
 
3 Less than 1 week between diagnosis time and contact with recruiter 
4 As acetylsalicylic acid 

4. Has used PPIs 14 day prior to diagnostic testing 
5. Use of antibiotics within 4 weeks beforehand. 
6. History of gastrointestinal bleeding for the last 12 weeks. 
7. History of partial gastrectomy due to Gastric Cancer 
8. History of incipient Gastric Cancer resolved by endoscopic resection. 
9. History of bariatric surgery. 
10. Serious or malignant diseases with less than 1 year life expectancy. 
11. History of Clostridium difficile infection. 
12. History of inflammatory bowel disease. 
13. Chronic kidney disease, stage 3 or higher. 
14. Do not sign informed consent. 
Context and locations where the data will be collected 
Participants will be recruited into the UC-CHRISTUS Health Network located  in the City of Santiago de 
Chile. The recruitment process is projected to last 6 months, during July to December 2022, considering 
an additional 3 months for eradication confirmation by urea breath test. 
Interventions for each group 
As previously mentioned, this study compares the Quadruple Therapy with the Standard Triple Therapy, 
detailed in the Table 1.  
Participants who no not achieve infection eradication will be referred to the gastroenterology team. They  
will be responsible for providing  second line treatment under the current standard of care. 
Table 1. Description of the intervention and control of the study. 
Intervention: 
Quadruple Therapy 
Control: 
Standard Triple Therapy 
Esomeprazole 40 mg every 8 hours 
Omeprazole 20mg every 12 hours 
Amoxicillin 1 gr every 8 hours 
Amoxicillin 1 gr every 12 hours 
Metronidazole 500 mg every 8 
hours 
Clarithromycin 500 mg every 12 
hours 
Bismuth subsalicylate  246 mg, 1.5 
tablets, every 8 hours 
Placebo identical to Bismuth 
Subsalicylate, 1.5 Tablets 3 times 
daily 

Primary and secondary outcomes 
Primary outcome: 
H. pylori Eradication: To determine eradication, participants of these study will be invited 8 to 12 weeks 
after the end of the administered therapy. Each participant will be given a Urea Breath Test (UBT) for 
eradication confirmation. This test has been widely validated by all International Consensus and Clinical 
Guidelines, given its excellent sensitivity, specificity, safety and acceptance by patients5 (4, 10, 11, 19).  If 
the participant reports antibiotic or proton pump inhibitor use in the last 15 days, appointments will be 
rescheduled at least for 15 days later.  This study will be complemented with a serology test for H. pylori, 
for which a blood sample will be taken at the time of recruitment and during the UBT appointment. 
Secondary-exploratory outcomes: 
Incidence of Adverse Drug Reactions (ADRs): A questionnaire will be performed to determine the 
occurrence of any adverse effect attributable to the therapy. The incidence of bloating, abdominal pain, 
bitter taste, constipation, diarrhea, dizziness, dyspepsia, epigastric pain, halitosis, headache, loss of 
appetite, nausea, vomiting, oral ulcers, skin rashes and drowsiness will be directly recorded. Symptoms 
reported by participants spontaneously in follow-up phone calls will also be recorded.  The time of 
commencement and duration of the therapy will be recorded. 
H. pylori Antibiotic Resistance and Host CYP2C19 polymorphisms determination: 
For DNA extraction the same gastric biopsy used for the rapid urease test (Pronto Dry) in endoscopy prior 
to admission will be used. No additional samples will be taken than those required as part of routine 
clinical practice. DNA will be extracted the biopsy using the QIAamp DNA mini kit (Quiagen) according to 
the manufacturer's instructions. 
To determine the susceptibility to Clarithromycin, PCRs will be performed with specific allele primers (ASP-
PCR) for point mutations A2142G and A2143G of the H. pylori 23s rRNA gene. Two pairs of primers will be 
used; the first pair targets a 320 bp fragment of the gene containing the mutation sites and consists of FP-
1 5′TCGAAGGTTAAGAGGATGCGTCAGTC3′ and RP-1 5′GACTCCATAAGAGCCAAAGCCCTTAC3′; the second 
 
5 For UBT one capsule of 75 of Urea with isotopic marker of carbon 13 (13C) will be administered with 50 mL of water. 
After 10 minutes, the participant will be asked to exhale in a bag. The resulting breath sample is analyzed with an 
infrared mass spectrometry device attached to a computer, which results in: 
1. Positive (delta on baseline ≥4%) 
2. Negative (delta on baseline <2.5%) 
3. Inconclusive: delta values between 2.5% and 4% 

pair is composed of the primers targeting the respective mutations, FP2143G 5′CCGCGGCAAGACAGAGA3' 
and RP2142G 5′AGTAAAGCCACCACGGGGTATTCC3′. For PCR an initial denaturation step will be performed 
at 95°C for 5 minutes, followed by 40 cycles of denaturation at 95°C for 15 seconds, hybridization at 60.5°C 
for 20 seconds, extension at 68°C for 30 seconds and a final extension for 2 minutes at 68°C.  The 
visualization of the results will be done in a 3% agarose gel. Strains that possessed fragments of 320 bp 
will be considered as wild type and those that had fragments of 238 bp and 118 bp as strains containing 
the mutation A2142G and A2143G, respectively.   
Different point mutations of the gyrA gene determinant region for quinolone resistance (QRDR) are 
responsible for conferring resistance to Levofloxacin. ASP-PCR will be performed. Primers are described 
in TABLE N°x.  
Table N°X Primers for detecting LEV resistance in the gyrA gene 
Primer 
Sequence (5’→3’) 
Mutation 
F261A1 CCCCCATGGCGAGAAAG  
C261A 
 
F261G1 CCCCCATGGCGAGAAGG  
C261G 
F271A5 GCGATAACGCGGTTTAGAA  
C271A 
F271A9 GCGATAATGCGGTTTAGAA  
G271A 
F271T9 GGCGATAATGCGGTTAATTA  
G271T 
F272G1 GCGATAACGCGGTTTAGGGT  
A272G 
F272G9 GCGATAATGCGGTTTAGGGT  
A272G 
F87ATC CCCCCATGGCGAGATCG  
A260T, T261C 
gyrA R 
GTTAGGCAGACGGCTTGGTARAATA 
C261A 
 
For PCR an initial denaturation will be performed at 94°C for 2 minutes, followed by 40 cycles of 
denaturation at 98°C for 10 seconds, hybridization at 65°C for 30 seconds, extension at 68°C for 20 seconds 
and a final extension for 2 minutes at 68°C.  The visualization of the results will be done in a 2% agarose 

gel. Strains with fragments of 428 bp will be considered as wild type and those who show a fragment of 
254 bp will be considered as resistant to LEV mutants. 
For Amoxicillin and Metronidazole resistance PCR amplification of fragments of interest for the pbp-1 and 
rdxA/frxA resistance genes respectively will be performed. Primers are described in Table N°X. PCR 
fragments will be visualized in a 1% agarose gel then purified for sanger sequencing.  
Table N°X Primers for pbp-1, rdxA and frxA gene amplification  
Primer 
Sequence (5’→3’) 
Fragment size  Ref 
bp-1 Fw CGATAGATTTGGATTACCAACGC 
1035 bp 
pbp-1 R ACGATTTCTTTACGCAAGCC 
rdxA Fw GCAGGAGCATCAGATAGTTCT 
886 bp 
rdxA R 
GGGATTTTATTGTATGCTACAA 
frxA Fw 
GGATATGGCAGCCGTTTATCATT 
780 bp 
frxA R 
GAATAGGCATCATTTAAGAGATTA 
 
To perform host CYP2C19 polymorphisms genotyping real time PCR using TaqMan probes for the Drug 
Metabolism Genotyping Assay of the to detect variants *2 (c.681G >A; rs 4244285), *3 (c. 636G >A; RS 
4986893) and *17 (−806C >T; RS 12248560). 
Covariates 
1. Sex 
2. Age 
3. BMI 
a. Weight 
b. Size 
4. Socioeconomic status: Income, activity, level of education. 
5. Comorbidities 
a. Use of medications 

6. Family history of Helicobacter pylori 
7. Feeding Patterns 
8. Degree of Therapeutic Adherence: A Spanish  version of The Morisky scale of medication 
adherence (MMAS-8) (25),  which has already  been used in Chile (26), will be adapted and 
applied. 
Questions 
Answer Options 
Assigned 
score 
1. Have you forgotten to take the medicine for Helicobacter 
pylori? 
Yes/No 
0/1 
2. Some people miss taking their medicines for other reasons 
and not just forgetting. If you remember the last two weeks, 
was there a day when you forgot to take the medicine for 
Helicobacter pylori? 
Yes/No 
0/1 
3. Have you reduced your dose or stopped taking the medicine 
because you felt worse about taking it? 
Yes/No 
0/1 
4. When traveling or away from home, do you ever forget to 
bring the medicine for Helicobacter pylori ? 
Yes/No 
0/1 
5. Did you take the medicine for Helicobacter pylori yesterday? 
Yes/No 
0/1 
6. When you feel that your stomach discomfort is under 
control, have you stopped taking your Medicine for 
Helicobacter pylori? 
Yes/No 
0/1 
7. Taking medication every day can be a problem for many 
people. Do you ever feel pressured to follow medical 
treatment for Helicobacter pylori? 
Yes/No 
0/1 
8. How often do you have trouble remembering to take all 
your medicines? 
Never/Almost 
never 
Seldom 
Sometimes 
Habitually 
Always 
1 
0,75 
0,5 
0,25 
0 
 
Covariates will be recorded at recruitment. For ADRs and therapeutic adherence telephone follow-up will 
be performed on days 7 and 14 and 21 after initiation of the therapy.  The last follow-up will be performed 
in person at the time of the UBT. 
Sample size calculation 
For sample size calculations the following are considered: 
Table 2. Parameters for the calculation of sample size. Values obtained from a Chilean population study  (23). 
Variable 
Value 

Expected Eradication rate with control therapy 
scheme 
82% 
Expected Eradication rate with intervention 
therapy scheme 
97% 
Expected absolute difference between therapies 
15% 
Power 
80% 
Confidence 
95% 
 
This calculation shows that 65 participants per branch are needed. Calculations were performed with 
statistical program Stata 15 (27). Considering a loss of 10.0%, 72 patients per branch are considered. In 
addition, we considered 30 additional patients in case the groups resulting from randomization are not 
balanced and it is necessary to adjust the effectiveness of the treatments, by 3 variables to be able to 
make regression analysis. With this, a total of 102 patients per branch will be included in this study.  
Methods used to generate the sequence for patient random assignment to branches 
For the assignment of participants in the intervention or control branches, a list of random numbers will 
be used in the sequencing of containers containing the control or intervention treatments. They will be 
delivered to the study participants according to the order in which they are recruited.  The process is 
showed in Figure 1. 
Mechanism used to implement branch random assignment 
For the anonymization of the sequence, the research team will delegate the generation of the random 
sequence and the numbering of the containers to a team that has no participation or knowledge of the 
design of the study, the collection or analysis of data. 
Generation of the assignment sequence, recruitment of participants and assignment 
of participants to the intervention’s responsibilities 
The research team will deliver 174 containers with the intervention or control (87 of each) to 2 members 
of the UC Pharmacology and Toxicology Program. They will generate the randomization sequence, 
number the containers according to their result and keep the record of the randomization sequence until 
the data collection is finished, and the statistical analysis is done then the blind opens.  In this way 
responsibilities are assigned to:  

A. Generation of the branch assignment sequence: UC Pharmacology and Toxicology Program 
B. Participant Recruitment: Principal Investigator 
C. Assignment of participants to the interventions: Principal investigator delivers the containers to 
the participants, keeping the blind by the randomization and previous numbering of the 
containers. 
 
Blind status maintenance for participants and research team  
To maintain a blind status to branch assignment: 
A. Part of the research team that performs patients recruitment 
B. Part of the research team that performs follows up on participants 
C. Part of the research team that performs test for confirmation of eradication of H. pylori 
D. Part of the research team that performs statistical analysis 
If relevant, the description of the similarity of the interventions 
Each participant will receive a box that was previously randomized, the contents of the boxes are: 
Container with Intervention therapy scheme 
Container with Control therapy scheme 
Figure 1. Randomization system of study participants. 
 

1. 42 tablets of esomeprazole 40 mg 
2. 42 amoxicillin tablets of 1. 000 mg 
3. 42 tablets of metronidazole 500 mg 
4. 63 bismuth Subsalicylate tablets 246 mg 
5. Therapy administration instructions 
1. 28 omeprazole tablets 20 mg 
2. 28 amoxicillin tablets of 1. 000 mg 
3. 28 tablet of clarithromycin 500 mg 
4. 42  bismuth  Subsalicylate placebo tablets 
5. Therapy administration instructions 
 
The control and intervention containers will look the same. 
Statistical methods used for group comparison of primary and secondary outcomes 
General 
The statistical analysis will be performed without knowledge of therapy scheme assignment, or the clinical 
evaluation of participants included in the study. P values <0,05 will be considered statistically significant.  
The analyses will be carried out under the intention-to-treat (ITT) modality. 
Registration and safeguarding of the data collected 
Data logging has 3 stages: 
1. Recruitment 
2. Telephone follow-ups days 7, 14 and 21 after starting treatment. 
3. UBT exam between 8 and 12 weeks after treatment ends. 
Each of these stages will have a physical record on paper, which will be transcribed into the REDCap 
electronic registry.  The paper records will be maintained under lock and key at the Toxicological and Drug 
Information Center (CITUC), located at Lira 63, second floor. 
Regarding the quality of the data recorded 
At the time of analysis, a random sample of 10% of the participants will be selected to evaluate the 
consistency between the physical and electronic record. If there are doubts in the quality of the 
information, all records will be checked.  Anomalous values will also be checked in the physical register. 
Data Analysis Plan 
Descriptive Statistics 
Descriptive statistics will be performed to determine the characteristics of the complete cohort and 
stratified by experimental branch.  The balance of the intervention and control groups will be evaluated. 
If the balance is not reached, the effect will be directly adjusted with multivariate models. 

Primary analysis: Comparison of treatment efficacy 
We will perform comparison for eradication percentages between groups by inferential statistical tests, 
to determine whether the difference between the groups reaches statistical significance.  We will also 
calculate Relative risk measures.  We will analyze variables associated with positive eradication and 
perform a multivariate analysis of factors associated with eradication using binomial regression. 
Secondary analysis: Adverse drug reactions 
Adverse reactions 
We will perform descriptive statistics, by type, particular symptom, and temporal evolution.  Comparison 
between control and intervention branches will be analyzed by the magnitude of ADR observed.  
Evaluation of association between ADR s with treatment scheme and covariates, by regression will be 
performed 
Sensitivity analysis 
To evaluate the robustness of the results, the analysis will be repeated in the modality by protocol to 
compare them with those obtained under the intention-to-treat modality.  Secondly, the effect of 
therapeutic adherence will be evaluated.  The analysis will also be stratified by the measured covariates, 
to evaluate sources of uncertainty, confusion, or possible interactions. 
Ethical Aspects 
Admission to the study is conditional on the reading and signing of informed consent, after the potential 
participant has understood what their participation consists of, as well as the risks and benefits associated 
with it. This study will be implemented and conducted in accordance with the Declaration of Helsinki and 
Ethical clinical practices. 
All drugs that will be used to conduct this research, both in the intervention and control branch are 
approved by the Institute of Public Health of Chile. They will be used within the typical therapeutic ranges 
of use thus interventions are considered safe for the study participants.  Endoscopies, venous sampling 
and UBT are all performed in centers of the UC-CHRISTUS Health Network, under standardized protocols 
that ensure the quality and safety of the procedures. 
Participants who fail to eradicate H. pylori will be treated using under standard of care conditions by the 
gastroenterology team that is part of the research team, at no cost. 

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