ETEC DiarrheaNCT06290089

Pre-Study of Wild Type Enterotoxigenic E. Coli (ETEC) Strain for Verification of a Planned Challenge Dose

A study testing Enterotoxigenic E. coli (ETEC) strain in people with ETEC Diarrhea, run by Scandinavian Biopharma AB at 1 site in United States.

Completed

Finished. The study has ended and is not enrolling. Results may be posted on the official record.

Official record

Search all trials

Trial summary

Who is it for?: Ages 18 to 50 yearsHealthy volunteers can take part
Conditions the study is for: ETEC Diarrhea
What is being tested?: Enterotoxigenic E. coli (ETEC) strain
Could I receive a placebo?: No, everyone receives an active treatment
How many people: 23 participants
Where: 1 siteUnited States
Study dates: 12 Feb 2024to 13 Sep 2024
Phase: Interventional
Are there results?: Yes, posted in the registrySummary in the doctors' view

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 18 to 50 years
All sexes
Healthy volunteers accepted
Adult

Who may be able to join

Healthy adults between 18 and 50 years of age, inclusive, at the time of signing the informed consent.
General good health, without clinically significant medical history, physical examination findings or clinical laboratory abnormalities per clinical judgment of PI.
Negative pregnancy test at screening and prior to challenge for people of childbearing potential. People of childbearing potential must agree to use an efficacious hormonal or barrier method of birth control during the study. Abstinence is acceptable. People of childbearing potential unable to bear children must have this documented (e.g. tubal ligation or hysterectomy) or must have negative pregnancy tests at screening and prior to challenge.
Willingness to participate in the study after all aspects of the protocol have been explained and written informed consent obtained.
Completion of a training session and demonstrated comprehension of the protocol procedures and knowledge of ETEC associated illness by passing a written examination (70% pass score).
Availability for the study duration, including planned follow-up visit/contact.

Who cannot join

Presence of a significant medical or psychiatric condition which in the opinion of the investigator precludes participation in the study, including gastrointestinal disease (gastritis, irritable bowel disease as suggested by Rome III criteria or medical diagnosis, inflammatory bowel disease). Some medical conditions which are adequately treated and stable would not preclude entry into the study. These conditions might include stable asthma controlled with inhalers or mild hypertension stably controlled.
Significant abnormalities in screening haematology, or serum chemistry as determined by PI.
Presence in the serum of HIV antibody, HBsAg, or HCV antibody with confirmation of infection (e.g. by HCV PCR).
Evidence of IgA deficiency (serum IgA < 7 mg/dl or limit of detection of assay).
Evidence of current alcohol or drug dependence.
Subjects whose Body Mass Index (BMI) is less than 19.0 or greater than 37.0 (kg/m2).

Show all 20Show fewer

Recent vaccination or receipt of an investigational product (within 30 days before challenge) or intended vaccination or receipt of investigational products until 60 days after challenge, with the exception of licensed vaccine for influenza or SARS-CoV-2 vaccination that may be given up to 7 days prior to challenge.
Positive test for SARS-CoV-2 at arrival to the unit on the day of in-patient admission.
Intention to donate blood or blood products within one month following the completion of study participation (note: The Red Cross will not allow blood donations for 1 year following participation in an investigational research study).
Any other criteria which, in the investigator's opinion, would compromise the ability of the subject to participate in the study, the safety of the study, or the results of the study.
Abnormal stool pattern (fewer than 3 per week or more than 3 per day).
Regular (≥ weekly) use of laxatives, antacids, or other agents to lower stomach acidity.
Use of any medication known to affect the immune function (e.g., corticosteroids and others) within 30 days preceding the challenge or planned use during the active study period. Use of inhaled or topical steroids may be permitted per PI discretion.
History of microbiologically confirmed ETEC infection in the last 3 years.
Occupational handling of ETEC currently, or in the past 3 years.
Travel to countries where ETEC infection is endemic (most of the developing world) within two years prior to dosing OR visit for > two months in ETEC endemic countries during the last 10 years, OR planned travel to endemic countries prior to study day 180.
Vaccination for or ingestion of ETEC, cholera, or LT toxin within 5 years prior to dosing.
Use of antibiotics during the 14 days before challenge dosing or proton pump inhibitors, H2 blockers or antacids within 48 hours prior to challenge dosing.
History of diarrhea in the 7 days prior to challenge (outpatient diarrhea is defined as ≥ 3 unformed (grade 3 or greater) loose stools in 24 hours).
Known allergy to two of the three following antibiotics: ciprofloxacin, amoxicillin, and/or azithromycin.

Trial locations and contacts

1 site in 1 country.

United States1 site

Center for Immunization Research, Johns Hopkins Bloomberg School of Public Health
Baltimore, Maryland, 21205

Other trials in United States

About this study

This was an open-label, single-site pre-study designed to evaluate the safety, tolerability, and infectivity of wild-type Enterotoxigenic Escherichia coli (ETEC) strain E24377A in healthy adults. The aim was to estimate the incidence of moderate and severe diarrhea following oral challenge with approximately 4 × 10⁹ colony forming units (cfu) of the strain.

A total of 23 participants were enrolled and monitored in an inpatient setting after receiving a single challenge dose. Clinical signs, symptoms, and stool output were assessed over 120 hours. This challenge model was developed to support a future controlled human infection study (CHIM) evaluating an oral inactivated ETEC vaccine.

Read the detailed description

This was an open-label, single-center pre-study designed to evaluate the safety, tolerability, and infectivity of wild-type Enterotoxigenic Escherichia coli (ETEC) strain E24377A in healthy adults. The goal was to estimate the incidence of moderate and severe diarrhea following challenge with approximately 4 × 10⁹ colony forming units (cfu) of the strain. This challenge model was intended to inform a subsequent controlled human infection model (CHIM) study assessing the efficacy of the oral inactivated tetravalent ETEC vaccine ETVAX® (containing LCTBA and dmLT).

Up to 30 healthy adult subjects were planned to be enrolled; 23 were ultimately challenged at the Center for Immunization Research (CIR), Johns Hopkins Bloomberg School of Public Health in Baltimore, Maryland, USA. Participants underwent screening, then entered an inpatient unit on Day -1. On Day 1, they received a single oral dose of strain E24377A (lot 0807) suspended in 30 mL sodium bicarbonate buffer, preceded by 120 mL of buffer to reduce gastric acidity.

During the inpatient period, subjects were monitored at least three times daily for vital signs, signs and symptoms of ETEC illness, and stool output. All stools were collected, weighed, graded, and cultured. Stools were graded on a 5-point scale: Grade 1 = firm/formed; Grade 2 = soft/formed; Grade 3 = thick liquid; Grade 4 = thin liquid; Grade 5 = clear/watery. Loose stools were defined as Grade 3-5.

Diarrhea was defined as ≥2 loose stools (Grade 3-5) within a 24-hour period. Severity was categorized as:

Mild: 2-3 Grade 3-5 stools and ≤400 g in 24 h

Moderate: 4-5 Grade 3-5 stools or >400-800 g

Severe: ≥6 Grade 3-5 stools or >800 g

An independent adjudication committee determined whether episodes were attributable to ETEC and whether participants met the primary endpoint. Participants received ciprofloxacin 500 mg twice daily for 3 days starting on Day 6, or earlier if needed. Discharge occurred after meeting microbiological and clinical criteria, with follow-up visits on Day 29 (clinic) and Day 180 (phone).

Secondary and exploratory endpoints included stool frequency and weight, symptom scores, microbiological shedding, and immunologic assessments (serum, fecal, and ALS IgA/IgG, memory B cells, transcriptomics, and biomarkers of intestinal/systemic inflammation). Safety endpoints included adverse events through Day 29 and serious adverse events through Day 180.

Conditions: ETEC Diarrhea
Being tested: Enterotoxigenic E. coli (ETEC) strain

What participants receive

What participants receive. In a randomised study each person is assigned to one group by chance.

Enterotoxigenic E. coli (ETEC) strainOther
Challenge strain

Study groups in NCT06290089
Study group	Role	What they receive
ETEC strain	Other	Each enrolled subject will receive a single administration of the challenge dose Receives: Other: Enterotoxigenic E. coli (ETEC) strain

What is being measured

The primary outcome is the main question the study is designed to answer.

Number of Participants With Moderate and Severe Diarrhea
Defined as ≥ 4 grade 3-5 stools or > 400 grams of grade 3-5 stools passed within a rolling 24-hour period, deemed attributable to ETEC
Measured: 120 hours post-challenge
Subjects Developing Moderate-to-Severe Diarrhea Following Oral Challenge
Each stool was to be graded according to the following scale:
Grade 1 = firm, formed Grade 2 = soft but still formed Grade 3 = thick liquid Grade 4 = thin liquid Grade 5 = clear or translucent, watery A loose stool was defined as a Grade 3-5 stool. Diarrhea was defined as passing at least 2 loose (Grade 3-5) stools within a 24-hour period.
Diarrhea severity was to be assigned according to the scale in Table 4.
Diarrhea Rating Scale:
Mild 2-3 Grade 3-5 stools in 24 hours and ≤ 400 grams of Grade 3-5 stools passed in a 24- hour period Moderate 4-5 Grade 3-5 stools in 24 hours or > 400-800 grams of Grade 3-5 stools passed in a 24-hour period Severe ≥ 6 Grade 3-5 stools in 24 hours or > 800 grams of Grade 3-5 stools passed in a 24-hours period.
Measured: up to 120 hours post-challenge

Timeline

From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.

12 Feb 202413 Sep 2024

First posted4 Mar 2024
Study start12 Feb 2024
Primary completion17 Feb 2024
Study completion13 Sep 2024

Resources

Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
Posted resultsParticipant flow, outcome measures and adverse events reported by the sponsor.
Other trials for ETEC DiarrheaStudies 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: Other
Allocation: Not applicable
Intervention model: Single group
Masking: None (open label)
Enrolment: 23 participants (actual)

IDs, dates and publications

ClinicalTrials.gov ID: NCT06290089
Sponsor's protocol ID: OEV-131
Status last verified: Jul 2025
First submitted: 26 Feb 2024
Last updated: 18 Jul 2025
Results posted: Yes, on ClinicalTrials.gov
FDA-regulated drug: No
FDA-regulated device: No

Study at a glance

From the registry record, last updated by the sponsor on 18 Jul 2025. Recruitment status is as the sponsor reported it: confirm with the study team.

Official title: Pre-Study of Wild Type Enterotoxigenic E. Coli (ETEC) Strain for Verification of a Planned Challenge Dose
ClinicalTrials.gov ID: NCT06290089
Acronym / sponsor ID: OEV-131
Conditions: ETEC Diarrhea
Study type: Interventional
Recruitment status: Completed
Enrolment: 23 participants (actual)
Lead sponsor: Scandinavian Biopharma ABIndustry (pharma, biotech, devices)
Collaborators: Johns Hopkins Bloomberg School of Public Health
Study start: 12 Feb 2024 (actual)
Primary completion: 17 Feb 2024 (actual)
Study completion: 13 Sep 2024 (actual)
First posted: 4 Mar 2024 (actual)
Results: Posted 16 Jul 2025

Clinical summary

The research question as the sponsor registered it. This describes what the study plans to test, not what it found.

Detailed description

Diarrhea was defined as ≥2 loose stools (Grade 3-5) within a 24-hour period. Severity was categorized as:

Mild: 2-3 Grade 3-5 stools and ≤400 g in 24 h

Moderate: 4-5 Grade 3-5 stools or >400-800 g

Severe: ≥6 Grade 3-5 stools or >800 g

Study design

Primary purpose: Other
Allocation: Not applicable
Intervention model: Single group
Masking: None (open label)
Number of arms: 1

Arm	Type	Receives
ETEC strain	Other	Other: Enterotoxigenic E. coli (ETEC) strainEach enrolled subject will receive a single administration of the challenge dose

Who may qualify

Ages: 18 to 50 years
Sex: All
Healthy volunteers: Accepted
Age groups: Adult

Key inclusion criteria (6 listed)

Healthy adults between 18 and 50 years of age, inclusive, at the time of signing the informed consent.
General good health, without clinically significant medical history, physical examination findings or clinical laboratory abnormalities per clinical judgment of PI.
Negative pregnancy test at screening and prior to challenge for people of childbearing potential. People of childbearing potential must agree to use an efficacious hormonal or barrier method of birth control during the study. Abstinence is acceptable. People of childbearing potential unable to bear children must have this documented (e.g. tubal ligation or hysterectomy) or must have negative pregnancy tests at screening and prior to challenge.
Willingness to participate in the study after all aspects of the protocol have been explained and written informed consent obtained.
Completion of a training session and demonstrated comprehension of the protocol procedures and knowledge of ETEC associated illness by passing a written examination (70% pass score).

Key exclusion criteria (20 listed)

Presence of a significant medical or psychiatric condition which in the opinion of the investigator precludes participation in the study, including gastrointestinal disease (gastritis, irritable bowel disease as suggested by Rome III criteria or medical diagnosis, inflammatory bowel disease). Some medical conditions which are adequately treated and stable would not preclude entry into the study. These conditions might include stable asthma controlled with inhalers or mild hypertension stably controlled.
Significant abnormalities in screening haematology, or serum chemistry as determined by PI.
Presence in the serum of HIV antibody, HBsAg, or HCV antibody with confirmation of infection (e.g. by HCV PCR).
Evidence of IgA deficiency (serum IgA < 7 mg/dl or limit of detection of assay).
Evidence of current alcohol or drug dependence.

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
Enterotoxigenic E. coli (ETEC) strainChallenge strain	Other	ETEC strain

Primary outcome

Number of Participants With Moderate and Severe Diarrhea
Time frame: 120 hours post-challenge
Defined as ≥ 4 grade 3-5 stools or > 400 grams of grade 3-5 stools passed within a rolling 24-hour period, deemed attributable to ETEC
Subjects Developing Moderate-to-Severe Diarrhea Following Oral Challenge
Time frame: up to 120 hours post-challenge
Each stool was to be graded according to the following scale: Grade 1 = firm, formed Grade 2 = soft but still formed Grade 3 = thick liquid Grade 4 = thin liquid Grade 5 = clear or translucent, watery A loose stool was defined as a Grade 3-5 stool. Diarrhea was defined as passing at least 2 loose (Grade 3-5) stools within a 24-hour period. Diarrhea severity was to be assigned according to the scale in Table 4. Diarrhea Rating Scale: Mild 2-3 Grade 3-5 stools in 24 hours and ≤ 400 grams of Grade 3-5 stools passed in a 24- hour period Moderate 4-5 Grade 3-5 stools in 24 hours or > 400-800 grams of Grade 3-5 stools passed in a 24-hour period Severe ≥ 6 Grade 3-5 stools in 24 hours or > 800 grams of Grade 3-5 stools passed in a 24-hours period.

Results and safety

Results posted to the registry on 16 Jul 2025, as reported by the sponsor. Figures are copied from the record, not re-analysed. Full results on ClinicalTrials.gov.

Participant flow

Group	Started	Completed
ETEC Strain	23	23

Primary outcome: Number of Participants With Moderate and Severe Diarrhea

Time frame: 120 hours post-challenge. Number. Unit: participants moderate or severe diarrea

Measure	ETEC Strain n = 23
Value	17

Population analysed: The Full Analysis Set includes all subjects who were challenged with E24377A (regardless of whether the whole intended challenge dose was ingested, or a subject vomited just after ingestion) and had available data. The Full Analysis Set was to be included in analyses of all endpoints

Primary outcome: Subjects Developing Moderate-to-Severe Diarrhea Following Oral Challenge

Time frame: up to 120 hours post-challenge. Number (95% Confidence Interval). Unit: percentage of subject with MSD

Measure	Challenge Dose Only Group n = 23
Value	74 (51.6 to 89.8)

Adverse events

Time frame: Unsolicited AEs were collected until Day 29, and SAEs and adverse events of special interest (AESIs) were collected until Day 180. Approximately 6 months after challenge, allsubjects will have a follow-up contact by telephone to inquire about the occurrence of any new chronic illnesses or serious adverse events. Other adverse events reported at 0% frequency or more

Group	Serious adverse events	Other adverse events	Deaths
ETEC Strain	0 of 23 (0%)	14 of 23 (60.9%)	0 of 23

Limitations and caveats (from the sponsor): The target enrollment was 30 participants, the data from the 23 enrolled subjects provided sufficient insight into the expected attack rates across diarrhea severity levels.

Loading the posted results from ClinicalTrials.gov…

Research links

Official record on ClinicalTrials.govLast updated by the sponsor 18 Jul 2025.
Posted resultsParticipant flow, baseline, all outcome measures and adverse events.

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. This study is not recruiting at the moment.

The record lists no contact. Use the official record to reach the sponsor.

1 site in 1 country: see every site and its status.

Questions about this trial

What is this clinical trial studying?

A study testing Enterotoxigenic E. coli (ETEC) strain in people with ETEC Diarrhea, run by Scandinavian Biopharma AB at 1 site in United States.

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 6 inclusion and 20 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: finished, as of the sponsor's last update on 18 Jul 2025. Status can change between updates, so confirm with the study contact before making plans.

Where is the study taking place?

The record lists 1 site in United States. 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?

Yes. Results are posted in the registry (first posted 16 Jul 2025). A summary is in the For doctors view, and the full results are on ClinicalTrials.gov.

How can a doctor refer a patient or contact the research team?

The record lists no contact. The official record names the sponsor, who can be asked directly. AzTrials does not enrol participants or take referrals.

What does the primary outcome measure?

Number of Participants With Moderate and Severe Diarrhea (time frame: 120 hours post-challenge). The study lists 2 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 NCT06290089.

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 18 Jul 2025.