Helicobacter Pylori InfectionNCT05926804
A "Screen and Treat" Helicobacter Pylori Eradication Trial in Adolescents in Three Regions of Chile
A study testing Lansoprazole, Amoxicillin and Clarithromycin in people with Helicobacter Pylori Infection, run by Miguel O'Ryan Gallardo at 3 sites in Chile.
Trial summary
Gastric cancer remains a global health problem, and Chile has one of the highest GC mortality rates in the region. Helicobacter pylori (H. pylori) infection is ubiquitous in Chilean adults, and it constitutes the main cause of GC worldwide. A long-term process occurs from premalignant lesions to carcinoma. H. Read more about this study
- Who is it for?
- Ages 14 to 18 yearsHealthy volunteers can take part
- Conditions the study is for
- Helicobacter Pylori Infection
- What is being tested?
- Lansoprazole, Amoxicillin and Clarithromycin
- Could I receive a placebo?
- No, everyone receives an active treatment
- How many people
- 500 participants
- Where
- 3 sitesChile
- Study dates
- 2 Aug 2022to Aug 2027
- Phase
- Interventional
- Are there results?
- Not yet: the study is under way
Key requirements
Who can take part, as listed by the sponsor. Only the study team can confirm whether you are eligible, so take this list to your doctor.
- Ages 14 to 18 years
- All sexes
- Healthy volunteers accepted
- Child, Adult
Who may be able to join
- Healthy teenagers 14-18 years of age from Colina, Temuco or Coyhaique
- At least one responsible adult family member accessible for phone contact.
- Persistent H. pylori infection determined by at least 2 positive UBT tests in a 3 months period (except for Non-infected Controls)
Who cannot join
- Teenagers not consenting to treatment will be invited to continue as non-treated controls.
- Known allergy to any of the antimicrobials used in the trial protocol (except for Non-infected Controls)
- Signs/symptoms compatible with organic abdominal pain according to Rome IV criteria: persistent right upper or right lower quadrant pain, dysphagia, odynophagia, persistent vomiting, gastrointestinal blood loss, involuntary weight loss, deceleration of linear growth, delayed puberty.
- Prior eradication therapy
- Antimicrobial course received during the previous month (at least 3 days of treatment at appropriate dosing, children meeting this criteria can be included at a later stage)
- Pregnancy
- Use of immunosuppressive or biologic drugs
- Children deemed "not healthy" after review of the questionnaire by study physician
Trial locations and contacts
3 sites in 1 country. Contact the study team or a site near you to ask about taking part.
Chile3 sites, 3 recruiting
- Recruiting
Universidad de Aysén
Coyhaique
Beatriz Zabala, PhD, +56996503803, beatriz.zabala@uaysen.cl
- Recruiting
Universidad de Chile
Santiago
Sergio George, MD, PhD, +56225756103, sgeorge@ug.uchile.cl
- Recruiting
Universidad de la Frontera
Temuco
Lilian Fernández, MD, +56984282646, liliufro@gmail.com
About this study
Official title: A Randomized "Screen and Treat" Helicobacter Pylori Eradication Trial in 14-18 Years Old Adolescents Residing in Three Regions of Chile: Effectiveness and Microbiological-host Implications
Gastric cancer remains a global health problem, and Chile has one of the highest GC mortality rates in the region. Helicobacter pylori (H. pylori) infection is ubiquitous in Chilean adults, and it constitutes the main cause of GC worldwide. A long-term process occurs from premalignant lesions to carcinoma. H. pylori eradication during early stages of disease significantly impacts outcomes, favoring survival, disease reversal and molecular changes, which supports a "screen and treat" strategy in asymptomatic populations in areas with intermediate-to-high GC prevalence. The Investigators' previous research has shown that H. pylori infection is acquired in early childhood with low rates of spontaneous eradication. A pilot treatment study in a subset of school-aged asymptomatic children showed a high rate of successful eradication (>95%), good tolerance, and was associated with a decrease in serum biomarkers of gastric damage (pepsinogen I and II). Based on the results of these studies, the Investigators propose to advance towards the next stage of this research process: a "screen and treat" strategy. The current trial starts with a Screening phase testing up to 1000 asymptomatic adolescents 14-18 years of age from 3 cities of Chile (Colina, Temuco and Coyhaique), to find a total of 210 persistently-infected participants. Persistently-infected adolescents will be included in a Second phase of this trial: A randomized, case-control, non-blinded study to either receive antimicrobial treatment targeting H. pylori eradication (cases) or no treatment (controls). A subset of 60 non-infected adolescents will be followed-up in matched times. This aims to provide evidence on the effect of treatment on clinical outcomes and serum biomarkers related to gastric damage, as well as composition and antimicrobial resistance of gut microbiota. The Investigators expect that eradication therapy will be successful in >90% of persistently infected adolescents, with reinfection rates not surpassing 15% in a 2-3 year period, and to be associated with a decrease in clinical findings indicative of gastric disease, and a decrease in serum biomarker indicative of "gastric damage".
Read the detailed description
Background: Helicobacter pylori (H. pylori) infection is the main cause of gastric cancer (GC), and long-term process occurs from premalignant lesions to carcinoma. H. pylori eradication during early stages of disease in young adults ("screen and treat") significantly impacts GC favoring survival, disease reversal and molecular changes. Effects of eradication therapy in affecting gut microbiome diversity and composition, and increasing antibiotic resistance rates in commensal bacteria, appear to be transient in most studies. The investigators have shown that infection is acquired mainly during the first 5 years of life, most infected children remain persistently infected with low rates of spontaneous eradication and persistently infected children have more abdominal complaints and higher levels of pepsinogen (PG) II (marker of gastric damage). A pilot eradication trial in persistently infected school-aged children showed that with sequential triple therapy, eradication was achieved in 96.8% of children, and treated children had a decrease in PG I and II levels compared to non-treated. The Investigators propose a "screen and treat" strategy aimed at a transition age between childhood and adulthood, in areas with intermediate-high gastric cancer prevalence, to assess efficacy of eradication, its clinical and molecular benefits and potential microbial side effects. Aims: The primary aim will be to determine the effectiveness of H. pylori eradication therapy in 14-18 years old adolescents in three regions with nearly 20-25% persistence rates, and determine the effect of eradication on clinical and serum biomarkers of gastric disease/damage. The secondary aims will be to determine the effects of H. pylori eradication therapy on antimicrobial resistance of potentially pathogenic enteric bacteria, and on gut microbiome composition. Exploratory aims: To determine the presence of clarithromycin resistance genes in H. pylori by stool analysis of children not achieving eradication, and determine the effects of reinfection on clinical findings indicative of gastric disease, and biomarkers indicative of "gastric damage", gut microbiota composition and antimicrobial resistance of H. pylori and other potentially pathogenic bacteria. Methods: The Investigators will invite, through contact with the health and educational authorities of Colina, Temuco and Coyhaique, 14-18 year old students until we reach up to 1000 adolescents enrolled. H. pylori screening test (Urea Breath Test; UBT) will be offered, and adolescents with a positive test will undergo two additional tests, separated by 30 days, in order to confirm infection persistence (at least two positive tests). It is expected that 20-25% of adolescents screened to be positive for H. pylori, of which over 90% will be persistently infected. 210 Subjects with persistent infection will then be randomized 2:1 to receive either an antimicrobial course targeting H. pylori eradication (7 days of lansoprazole and amoxicillin followed by 7 days of lansoprazole and clarithromycin plus metronidazole) or no treatment. Participants will be followed-up with UBT (1 month post treatment, and then every 6 months for the remaining surveillance period), gastroenterological evaluation (2 weeks pre treatment, 1 month, 3 months, 9 months and 18 months post treatment), blood samples and stool samples (2 weeks pre-treatment, 1 month and 6 months post treatment). A subset of 60 non-infected students from each site will be followed-up in matched times. To those subjects with persistent infection who do not receive treatment, the same eradication regimen will be offered after they have completed the initial 6-month follow-up with their blood and stool samples taken.
Serum gastric damage biomarkers will be assessed using GastroPanel® (PGI, PGII, Gastrin) and ELISA commercial kits (VCAM-1, CXCL13). Escherichia coli and Enterococcus spp will be cultured from stools samples, and resistance to 6 antimicrobials will be assessed by disk diffusion method. H. pylori clarithromycin resistance gene will be amplified from stools using nested-qPCR. Composition of gut microbiome will be characterized by amplification and sequencing the 16SrRNA gene from stools, ant then bioinformatics analysis. Expected results: The prevalence of persistent H. pylori infection will be around 20-25% in adolescents from Colina, Coyhaique and Temuco. Eradication will be successful in >90% of persistently infected students, and reinfection rates will not surpass 15% in a 2-3 year period. Eradication will be significantly associated with a decrease in clinical findings indicative of gastric disease, and a decrease in biomarker levels indicative of "gastric damage". Treatment will have a transitory effect on increasing antimicrobial resistance rates of potentially pathogen enteric bacteria (Escherichia coli, Enterococcus spp.). Treatment will have a transitory effect on disrupting gut microbiota composition at phylum, class, order, family and genus levels, which will be restored to levels comparable to non-infected healthy teenagers at the end of follow-up. In those adolescents for whom eradication therapy fails, clarithromycin resistance will be more prevalent in pretreatment samples compared to those eradicating H. pylori; in reinfected children, treatment will have a transitory effect on increasing detection rates of H. pylori clarithromycin resistance genes.
- Conditions
- Helicobacter Pylori Infection
- Being tested
- Lansoprazole, Amoxicillin, Clarithromycin, Metronidazole
- Keywords
- Helicobacter pylori, Screen and treat, Pepsinogen, Adolescent
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
LansoprazoleDrug
14 days of Lansoprazole (30 mg BID) (days 1-14)
AmoxicillinDrug
7 days of Amoxicillin (1000 mg BID) (days 1-7)
ClarithromycinDrug
7 days of Clarithromycin (500 mg BID) (days 8-14)
MetronidazoleDrug
7 days of Metronidazole (500 mg BID) (days 8-14)
| Study group | Role | What they receive |
|---|---|---|
| Cases | Experimental | 140 children with H. pylori-persistent infection, who will receive eradication therapy Receives: Drug: Lansoprazole; Drug: Amoxicillin; Drug: Clarithromycin; Drug: Metronidazole |
| Controls | No intervention | 70 children with H. pylori-persistent infection, who will not receive eradication therapy |
| Non infected Controls | No intervention | 60 adolescents with no H. pylori infection, they will not receive eradication therapy |
What is being measured
The primary outcome is the main question the study is designed to answer.
Percentage of persistently-infected teenagers which change UBT status from positive to negative 1 month post-treatment, as compared to non-treated subjects.
UBT samples will be obtained pre-treatment and 1 month post-treatment.
Measured: a. Baseline: 2 or 3 samples obtained pre-treatment (separated by 30 days) to detect persistently infected children b. One month post-treatment.
Change in the percentage of persistently-infected adolescents which have "gastric disease" according to gastroenterologist examination from baseline (pre-treatment) to 2-4 months post successful eradication therapy, as compared to non-treated subjects
Clinical evaluation by gastroenterologist or trained physician, blind to the treatment arm of the subject, for specific GI signs/symptoms, will be performed at baseline (during the month prior to treatment) and posttreatment (2-4 months post treatment). Successful eradication: Negative UBT sample 30 days after treatment
Measured: a. Baseline evaluation during the month prior to treatment. b. 2-4 months post treatment
Change in blood levels of biomarkers indicative of gastric damage in adolescents with successful eradication after treatment, as compared to non-treated subjects after 6 month follow up.
Blood samples for Pepsinogen (PG) I, PGII, gastrin and other potential biomarkers of "gastric damage. PGI/PGII/Gastrin-17: will be assessed in serum using GastroPanel® (Biohit Oyj, Helsinki, Finland). Two additional biomarkers of GC will be assessed by ELISA-commercial kits: VCAM-1 and CXCL13. Samples will be collected at baseline, 1 month and 6 months post treatment.
Measured: a. Baseline: Within 2 weeks before initiation of eradication treatment and at similar time-frame in non-treated age matched controls (pre-sample) b. 1 month after treatment c. 6 months post treatment
Secondary outcomes (2)
Change in faecal Escherichia coli and Enterococcus antimicrobial resistance rates in treated subjects from baseline to 1 month and 6-12 months post treatment, as compared to non-treated subjects.
Phenotypic antimicrobial susceptibility analysis of Escherichia coli and Enterococcus will be performed from stool samples obtained in both Cases and Controls by Kirby Bauer disc diffusion method. According to patterns of AMR of each bacteria, and the antimicrobials used in this trials, E. coli will be tested against clarithromycin, ampicillin, ampicillin-sulbactam, cefazolin, ceftazidime, levofloxacin, and gentamicin; and Enterococcus will be tested against clarithromycin, ampicillin, ampicillin-sulbactam, penicillin, vancomycin and quinopristin/dalfopristin.
Measured: a. Baseline: Within one month before treatment b. 1 month post treatment c. 6-12 months post treatment (and at similar time-frame in non-treated age matched controls)]
Change in gut microbiome alpha-diversity index in treated subjects from baseline to 1 month and 6-12 months post-treatment, as compared to to non-treated subjects.
For microbiome analysis 30 stool samples from each group (Cases and controls) will be obtained pre and post treatment. Changes in gut microbiota composition in stool samples will be analyzed by sequencing of the 16S rRNA V3 to V4 hypervariable region using Illumina
Measured: a. Baseline: Within one month before treatment b. 1 month post treatment c. 6-12 months post treatment (and at similar time-frame in non-treated age matched controls)]
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted3 Jul 2023
- Study start2 Aug 2022
- Primary completionOct 2026 (estimated)
- Study completionAug 2027 (estimated)
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Publications (5)Papers the sponsor has linked to this study.
- Other trials for Helicobacter Pylori InfectionStudies of the same condition, open and under way.
- What the trial phases meanHow a treatment moves from first tests in people to approval.
More details
For doctors and researchers: how the study is designed, who runs it, and its registry IDs.
Study design
- Study type
- Interventional
- Phase
- Phase N/A
- Primary purpose
- Treatment
- Allocation
- Randomised
- Intervention model
- Parallel groups
- Model description
- Screening phase: 14-18-year-old students (up to 1000) from three cities will be invited. After obtaining informed consent, eligible participants without exclusion criteria will undergo an H. pylori screening test (Urea Breath Test; UBT). Those negative will exit, except for a subset to be followed as a non-infected controls. Subjects with a positive test will undergo two confirmatory tests 30 days apart to confirm infection persistence. Approximately 20-25% are expected to be positive. Intervention phase: those with persistent H. pylori infection will undergo gastroenterological evaluation 1 month before randomization (2:1) to receive antimicrobial treatment or no treatment. Non-infected controls will be followed at matched intervals. If untreated, subjects with persistent infection will be offered the eradication regimen after completing the initial 6-month follow-up with blood and stool samples taken.
- Masking
- Single blind
- Who is masked
- Outcomes assessor
- Enrolment
- 500 participants (estimated)
Sponsor and investigators
- Lead sponsor
- Miguel O'Ryan Gallardo
- Sponsor type
- University, hospital or other
- Collaborators
- Fondo Nacional de Desarrollo Científico y Tecnológico, Chile
- Responsible party
- Sponsor-investigator, Miguel O'Ryan Gallardo, University of Chile
- Investigators
- Miguel O'Ryan, MD, Principal investigator, University of Chile
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT05926804
- Sponsor's protocol ID
- 1220964
- Other IDs
- 1220964
- Status last verified
- Dec 2025
- First submitted
- 1 Jun 2023
- Last updated
- 17 Dec 2025
- Results posted
- No
- FDA-regulated drug
- No
- FDA-regulated device
- No
- Individual data sharing
- Yes: Individual participant data that underlie the results reported in the article after deidentification (text, tables, figures, and appendices), will be shared upon request, as well as the study protocol and questionnaires. Previous authorization of the Human Research Ethics Committee at the Faculty of Medicine, University of Chile will be requested.
Publications
O'Ryan ML, Lucero Y, Rabello M, Mamani N, Salinas AM, Pena A, Torres-Torreti JP, Mejias A, Ramilo O, Suarez N, Reynolds HE, Orellana A, Lagomarcino AJ. Persistent and transient Helicobacter pylori infections in early childhood. Clin Infect Dis. 2015 Jul 15;61(2):211-8. doi: 10.1093/cid/civ256. Epub 2015 Apr 2.
PubMed 25838286O'Ryan ML, Rabello M, Cortes H, Lucero Y, Pena A, Torres JP. Dynamics of Helicobacter pylori detection in stools during the first 5 years of life in Chile, a rapidly developing country. Pediatr Infect Dis J. 2013 Feb;32(2):99-103. doi: 10.1097/INF.0b013e318278b929.
PubMed 23076385Lucero Y, Lagomarcino AJ, Torres JP, Roessler P, Mamani N, George S, Huerta N, Gonzalez M, O'Ryan M. Helicobacter pylori, clinical, laboratory, and noninvasive biomarkers suggestive of gastric damage in healthy school-aged children: A case-control study. Int J Infect Dis. 2021 Feb;103:423-430. doi: 10.1016/j.ijid.2020.11.202. Epub 2020 Dec 2.
PubMed 33278617Lucero Y, Lagomarcino AJ, Torres JP, Roessler P, Mamani N, George SA, Huerta N, Gonzalez M, O'Ryan G M. Effect of Helicobacter pylori eradication therapy on clinical and laboratory biomarkers associated with gastric damage in healthy school-aged children: A randomized non-blinded trial. Helicobacter. 2021 Dec;26(6):e12853. doi: 10.1111/hel.12853. Epub 2021 Sep 15.
PubMed 34528337George S, Lucero Y, Cabrera C, Zabala Torres B, Fernandez L, Mamani N, Lagomarcino A, Aguilera X, O'Ryan M. Protocol for a randomised 'screen-and-treat' Helicobacter pylori eradication trial in 14-18-years-old adolescents residing in three regions of Chile: effectiveness and microbiological host implications. BMJ Open. 2025 Jan 30;15(1):e084984. doi: 10.1136/bmjopen-2024-084984.
PubMed 39890135
Study at a glance
From the registry record, last updated by the sponsor on 17 Dec 2025. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- A Randomized "Screen and Treat" Helicobacter Pylori Eradication Trial in 14-18 Years Old Adolescents Residing in Three Regions of Chile: Effectiveness and Microbiological-host Implications
- ClinicalTrials.gov ID
- NCT05926804
- Acronym / sponsor ID
- 1220964
- Conditions
- Helicobacter Pylori Infection
- Keywords
- Helicobacter pylori, Screen and treat, Pepsinogen, Adolescent
- Study type
- Interventional
- Recruitment status
- Recruiting
- Enrolment
- 500 participants (estimated)
- Lead sponsor
- Miguel O'Ryan GallardoUniversity, hospital or other
- Collaborators
- Fondo Nacional de Desarrollo Científico y Tecnológico, Chile
- Study start
- 2 Aug 2022 (actual)
- Primary completion
- Oct 2026 (estimated)
- Study completion
- Aug 2027 (estimated)
- First posted
- 3 Jul 2023 (actual)
- Results
- Not posted in the source record
Clinical summary
The research question as the sponsor registered it. This describes what the study plans to test, not what it found.
Gastric cancer remains a global health problem, and Chile has one of the highest GC mortality rates in the region. Helicobacter pylori (H. pylori) infection is ubiquitous in Chilean adults, and it constitutes the main cause of GC worldwide. A long-term process occurs from premalignant lesions to carcinoma. H. pylori eradication during early stages of disease significantly impacts outcomes, favoring survival, disease reversal and molecular changes, which supports a "screen and treat" strategy in asymptomatic populations in areas with intermediate-to-high GC prevalence. The Investigators' previous research has shown that H. pylori infection is acquired in early childhood with low rates of spontaneous eradication. A pilot treatment study in a subset of school-aged asymptomatic children showed a high rate of successful eradication (>95%), good tolerance, and was associated with a decrease in serum biomarkers of gastric damage (pepsinogen I and II). Based on the results of these studies, the Investigators propose to advance towards the next stage of this research process: a "screen and treat" strategy. The current trial starts with a Screening phase testing up to 1000 asymptomatic adolescents 14-18 years of age from 3 cities of Chile (Colina, Temuco and Coyhaique), to find a total of 210 persistently-infected participants. Persistently-infected adolescents will be included in a Second phase of this trial: A randomized, case-control, non-blinded study to either receive antimicrobial treatment targeting H. pylori eradication (cases) or no treatment (controls). A subset of 60 non-infected adolescents will be followed-up in matched times. This aims to provide evidence on the effect of treatment on clinical outcomes and serum biomarkers related to gastric damage, as well as composition and antimicrobial resistance of gut microbiota. The Investigators expect that eradication therapy will be successful in >90% of persistently infected adolescents, with reinfection rates not surpassing 15% in a 2-3 year period, and to be associated with a decrease in clinical findings indicative of gastric disease, and a decrease in serum biomarker indicative of "gastric damage".
Detailed description
Background: Helicobacter pylori (H. pylori) infection is the main cause of gastric cancer (GC), and long-term process occurs from premalignant lesions to carcinoma. H. pylori eradication during early stages of disease in young adults ("screen and treat") significantly impacts GC favoring survival, disease reversal and molecular changes. Effects of eradication therapy in affecting gut microbiome diversity and composition, and increasing antibiotic resistance rates in commensal bacteria, appear to be transient in most studies. The investigators have shown that infection is acquired mainly during the first 5 years of life, most infected children remain persistently infected with low rates of spontaneous eradication and persistently infected children have more abdominal complaints and higher levels of pepsinogen (PG) II (marker of gastric damage). A pilot eradication trial in persistently infected school-aged children showed that with sequential triple therapy, eradication was achieved in 96.8% of children, and treated children had a decrease in PG I and II levels compared to non-treated. The Investigators propose a "screen and treat" strategy aimed at a transition age between childhood and adulthood, in areas with intermediate-high gastric cancer prevalence, to assess efficacy of eradication, its clinical and molecular benefits and potential microbial side effects. Aims: The primary aim will be to determine the effectiveness of H. pylori eradication therapy in 14-18 years old adolescents in three regions with nearly 20-25% persistence rates, and determine the effect of eradication on clinical and serum biomarkers of gastric disease/damage. The secondary aims will be to determine the effects of H. pylori eradication therapy on antimicrobial resistance of potentially pathogenic enteric bacteria, and on gut microbiome composition. Exploratory aims: To determine the presence of clarithromycin resistance genes in H. pylori by stool analysis of children not achieving eradication, and determine the effects of reinfection on clinical findings indicative of gastric disease, and biomarkers indicative of "gastric damage", gut microbiota composition and antimicrobial resistance of H. pylori and other potentially pathogenic bacteria. Methods: The Investigators will invite, through contact with the health and educational authorities of Colina, Temuco and Coyhaique, 14-18 year old students until we reach up to 1000 adolescents enrolled. H. pylori screening test (Urea Breath Test; UBT) will be offered, and adolescents with a positive test will undergo two additional tests, separated by 30 days, in order to confirm infection persistence (at least two positive tests). It is expected that 20-25% of adolescents screened to be positive for H. pylori, of which over 90% will be persistently infected. 210 Subjects with persistent infection will then be randomized 2:1 to receive either an antimicrobial course targeting H. pylori eradication (7 days of lansoprazole and amoxicillin followed by 7 days of lansoprazole and clarithromycin plus metronidazole) or no treatment. Participants will be followed-up with UBT (1 month post treatment, and then every 6 months for the remaining surveillance period), gastroenterological evaluation (2 weeks pre treatment, 1 month, 3 months, 9 months and 18 months post treatment), blood samples and stool samples (2 weeks pre-treatment, 1 month and 6 months post treatment). A subset of 60 non-infected students from each site will be followed-up in matched times. To those subjects with persistent infection who do not receive treatment, the same eradication regimen will be offered after they have completed the initial 6-month follow-up with their blood and stool samples taken.
Serum gastric damage biomarkers will be assessed using GastroPanel® (PGI, PGII, Gastrin) and ELISA commercial kits (VCAM-1, CXCL13). Escherichia coli and Enterococcus spp will be cultured from stools samples, and resistance to 6 antimicrobials will be assessed by disk diffusion method. H. pylori clarithromycin resistance gene will be amplified from stools using nested-qPCR. Composition of gut microbiome will be characterized by amplification and sequencing the 16SrRNA gene from stools, ant then bioinformatics analysis. Expected results: The prevalence of persistent H. pylori infection will be around 20-25% in adolescents from Colina, Coyhaique and Temuco. Eradication will be successful in >90% of persistently infected students, and reinfection rates will not surpass 15% in a 2-3 year period. Eradication will be significantly associated with a decrease in clinical findings indicative of gastric disease, and a decrease in biomarker levels indicative of "gastric damage". Treatment will have a transitory effect on increasing antimicrobial resistance rates of potentially pathogen enteric bacteria (Escherichia coli, Enterococcus spp.). Treatment will have a transitory effect on disrupting gut microbiota composition at phylum, class, order, family and genus levels, which will be restored to levels comparable to non-infected healthy teenagers at the end of follow-up. In those adolescents for whom eradication therapy fails, clarithromycin resistance will be more prevalent in pretreatment samples compared to those eradicating H. pylori; in reinfected children, treatment will have a transitory effect on increasing detection rates of H. pylori clarithromycin resistance genes.
Study design
- Primary purpose
- Treatment
- Allocation
- Randomised
- Intervention model
- Parallel groups
- Masking
- Single blind (outcomes assessor)
- Number of arms
- 3
- Model description
- Screening phase: 14-18-year-old students (up to 1000) from three cities will be invited. After obtaining informed consent, eligible participants without exclusion criteria will undergo an H. pylori screening test (Urea Breath Test; UBT). Those negative will exit, except for a subset to be followed as a non-infected controls. Subjects with a positive test will undergo two confirmatory tests 30 days apart to confirm infection persistence. Approximately 20-25% are expected to be positive. Intervention phase: those with persistent H. pylori infection will undergo gastroenterological evaluation 1 month before randomization (2:1) to receive antimicrobial treatment or no treatment. Non-infected controls will be followed at matched intervals. If untreated, subjects with persistent infection will be offered the eradication regimen after completing the initial 6-month follow-up with blood and stool samples taken.
| Arm | Type | Receives |
|---|---|---|
| Cases | Experimental | Drug: Lansoprazole, Drug: Amoxicillin, Drug: Clarithromycin, Drug: Metronidazole140 children with H. pylori-persistent infection, who will receive eradication therapy |
| Controls | No intervention | –70 children with H. pylori-persistent infection, who will not receive eradication therapy |
| Non infected Controls | No intervention | –60 adolescents with no H. pylori infection, they will not receive eradication therapy |
Who may qualify
- Ages
- 14 to 18 years
- Sex
- All
- Healthy volunteers
- Accepted
- Age groups
- Child, Adult
Key inclusion criteria (3 listed)
- Healthy teenagers 14-18 years of age from Colina, Temuco or Coyhaique
- At least one responsible adult family member accessible for phone contact.
- Persistent H. pylori infection determined by at least 2 positive UBT tests in a 3 months period (except for Non-infected Controls)
Key exclusion criteria (8 listed)
- Teenagers not consenting to treatment will be invited to continue as non-treated controls.
- Known allergy to any of the antimicrobials used in the trial protocol (except for Non-infected Controls)
- Signs/symptoms compatible with organic abdominal pain according to Rome IV criteria: persistent right upper or right lower quadrant pain, dysphagia, odynophagia, persistent vomiting, gastrointestinal blood loss, involuntary weight loss, deceleration of linear growth, delayed puberty.
- Prior eradication therapy
- Antimicrobial course received during the previous month (at least 3 days of treatment at appropriate dosing, children meeting this criteria can be included at a later stage)
Eligibility is decided by the study team after screening; this overview does not establish that a patient qualifies. Full inclusion and exclusion criteria.
Interventions
| Intervention | Type | Arms |
|---|---|---|
| Lansoprazole14 days of Lansoprazole (30 mg BID) (days 1-14) | Drug | Cases |
| Amoxicillin7 days of Amoxicillin (1000 mg BID) (days 1-7) | Drug | Cases |
| Clarithromycin7 days of Clarithromycin (500 mg BID) (days 8-14) | Drug | Cases |
| Metronidazole7 days of Metronidazole (500 mg BID) (days 8-14) | Drug | Cases |
Primary outcome
Percentage of persistently-infected teenagers which change UBT status from positive to negative 1 month post-treatment, as compared to non-treated subjects.
Time frame: a. Baseline: 2 or 3 samples obtained pre-treatment (separated by 30 days) to detect persistently infected children b. One month post-treatment.
UBT samples will be obtained pre-treatment and 1 month post-treatment.
Change in the percentage of persistently-infected adolescents which have "gastric disease" according to gastroenterologist examination from baseline (pre-treatment) to 2-4 months post successful eradication therapy, as compared to non-treated subjects
Time frame: a. Baseline evaluation during the month prior to treatment. b. 2-4 months post treatment
Clinical evaluation by gastroenterologist or trained physician, blind to the treatment arm of the subject, for specific GI signs/symptoms, will be performed at baseline (during the month prior to treatment) and posttreatment (2-4 months post treatment). Successful eradication: Negative UBT sample 30 days after treatment
Change in blood levels of biomarkers indicative of gastric damage in adolescents with successful eradication after treatment, as compared to non-treated subjects after 6 month follow up.
Time frame: a. Baseline: Within 2 weeks before initiation of eradication treatment and at similar time-frame in non-treated age matched controls (pre-sample) b. 1 month after treatment c. 6 months post treatment
Blood samples for Pepsinogen (PG) I, PGII, gastrin and other potential biomarkers of "gastric damage. PGI/PGII/Gastrin-17: will be assessed in serum using GastroPanel® (Biohit Oyj, Helsinki, Finland). Two additional biomarkers of GC will be assessed by ELISA-commercial kits: VCAM-1 and CXCL13. Samples will be collected at baseline, 1 month and 6 months post treatment.
2 secondary outcomes
Change in faecal Escherichia coli and Enterococcus antimicrobial resistance rates in treated subjects from baseline to 1 month and 6-12 months post treatment, as compared to non-treated subjects.
Time frame: a. Baseline: Within one month before treatment b. 1 month post treatment c. 6-12 months post treatment (and at similar time-frame in non-treated age matched controls)]
Change in gut microbiome alpha-diversity index in treated subjects from baseline to 1 month and 6-12 months post-treatment, as compared to to non-treated subjects.
Time frame: a. Baseline: Within one month before treatment b. 1 month post treatment c. 6-12 months post treatment (and at similar time-frame in non-treated age matched controls)]
Results and safety
This study is still under way. Results are not available in the source record yet.
Research links
- Official record on ClinicalTrials.govLast updated by the sponsor 17 Dec 2025.
- Background: PubMed 25838286O'Ryan ML, Lucero Y, Rabello M, Mamani N, Salinas AM, Pena A, Torres-Torreti JP, Mejias A, Ramilo O, Suarez N, Reynolds HE, Orellana A, Lagomarcino AJ. Persistent and transient Helicobacter pylori infections in early childhood. Clin Infect Dis. 2015 Jul 15;61(2):211-8. doi: 10.1093/cid/civ256. Epub 2015 Apr 2.
- Background: PubMed 23076385O'Ryan ML, Rabello M, Cortes H, Lucero Y, Pena A, Torres JP. Dynamics of Helicobacter pylori detection in stools during the first 5 years of life in Chile, a rapidly developing country. Pediatr Infect Dis J. 2013 Feb;32(2):99-103. doi: 10.1097/INF.0b013e318278b929.
- Background: PubMed 33278617Lucero Y, Lagomarcino AJ, Torres JP, Roessler P, Mamani N, George S, Huerta N, Gonzalez M, O'Ryan M. Helicobacter pylori, clinical, laboratory, and noninvasive biomarkers suggestive of gastric damage in healthy school-aged children: A case-control study. Int J Infect Dis. 2021 Feb;103:423-430. doi: 10.1016/j.ijid.2020.11.202. Epub 2020 Dec 2.
- Background: PubMed 34528337Lucero Y, Lagomarcino AJ, Torres JP, Roessler P, Mamani N, George SA, Huerta N, Gonzalez M, O'Ryan G M. Effect of Helicobacter pylori eradication therapy on clinical and laboratory biomarkers associated with gastric damage in healthy school-aged children: A randomized non-blinded trial. Helicobacter. 2021 Dec;26(6):e12853. doi: 10.1111/hel.12853. Epub 2021 Sep 15.
- Derived from this study: PubMed 39890135George S, Lucero Y, Cabrera C, Zabala Torres B, Fernandez L, Mamani N, Lagomarcino A, Aguilera X, O'Ryan M. Protocol for a randomised 'screen-and-treat' Helicobacter pylori eradication trial in 14-18-years-old adolescents residing in three regions of Chile: effectiveness and microbiological host implications. BMJ Open. 2025 Jan 30;15(1):e084984. doi: 10.1136/bmjopen-2024-084984.
- Individual participant dataSharing planned: Yes. Individual participant data that underlie the results reported in the article after deidentification (text, tables, figures, and appendices), will be shared upon request, as well as the study protocol and questionnaires. Previous authorization of the Human Research Ethics Committee at the Faculty of Medicine, University of Chile will be requested.
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Referral and contact
AzTrials does not enrol participants or take referrals. Contact the study team or a site listed below; they decide who can take part.
Miguel O'Ryan, MD principal investigator
University of Chile
3 sites in 1 country: see every site and its status.
Questions about this trial
What is this clinical trial studying?
A study testing Lansoprazole, Amoxicillin and Clarithromycin in people with Helicobacter Pylori Infection, run by Miguel O'Ryan Gallardo at 3 sites in Chile.
The full registered description is in the About this study section and the official record.
Who may be eligible to take part?
The sponsor lists 3 inclusion and 8 exclusion criteria. Eligibility is decided by the study team after screening, so read the full criteria and contact a listed site.
Is this clinical trial currently recruiting?
The record says: looking for participants now, as of the sponsor's last update on 17 Dec 2025. Status can change between updates, so confirm with the study contact before making plans.
Where is the study taking place?
The record lists 3 sites in Chile. Whether a site is taking part right now should be confirmed with that site. See every site.
What are the possible benefits and risks?
They depend on the study and the treatment, and no study can promise a benefit. The study team explains the known risks during informed consent, before anyone joins; the record itself does not list them.
Are results available for this study?
This study is still under way. Results are not available in the source record yet.
How can a doctor refer a patient or contact the research team?
Contact Yalda Lucero, MD, PhD (+56229786658, ylucero@uchile.cl), or a site near the patient. AzTrials does not enrol participants or take referrals.
What does the primary outcome measure?
Percentage of persistently-infected teenagers which change UBT status from positive to negative 1 month post-treatment, as compared to non-treated subjects. (time frame: a. Baseline: 2 or 3 samples obtained pre-treatment (separated by 30 days) to detect persistently infected children b. One month post-treatment.). The study lists 3 primary outcomes in all. It is what the study was designed to measure, not a finding.
Where can I read the original study information?
On the ClinicalTrials.gov record for NCT05926804, which also lists 5 linked publications.
Does a listing mean the treatment is approved or proven to work?
No. A listing means the study is registered. It does not show that the treatment is safe, works, or is approved by a regulator.
How often is this information updated?
AzTrials copies changed records from ClinicalTrials.gov every night and reloads the whole registry every week. The sponsor last updated this record on 17 Dec 2025.