Trial Outcomes & Findings for Pre-Study of Wild Type Enterotoxigenic E. Coli (ETEC) Strain for Verification of a Planned Challenge Dose (NCT NCT06290089)

Last Updated: 2025-07-18

Results Overview

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

Recruitment status

COMPLETED

Study phase

Target enrollment

23 participants

Primary outcome timeframe

120 hours post-challenge

Results posted on

2025-07-18

Participant Flow

Participant milestones

Participant milestones
Measure	ETEC Strain Each enrolled subject will receive a single administration of the challenge dose Enterotoxigenic E. coli (ETEC) strain: Challenge strain
Overall Study STARTED	23
Overall Study COMPLETED	23
Overall Study NOT COMPLETED	0

Reasons for withdrawal

Withdrawal data not reported

Baseline Characteristics

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

Baseline characteristics by cohort

Baseline characteristics by cohort
Measure	Challenge Dose Only Group n=23 Participants A total of 23 subjects were enrolled in this arm. All participants received a single oral challenge dose of ETEC strain E24377A . The objectives are to evaluate the moderate and severe diarrhea attack rate, the safety and the immunogenicity. No prior vaccination was administered in this group.
Age, Continuous	39 year STANDARD_DEVIATION 8.1 • n=5 Participants
Sex: Female, Male Female	7 Participants n=5 Participants
Sex: Female, Male Male	16 Participants n=5 Participants
Ethnicity (NIH/OMB) Hispanic or Latino	4 Participants n=5 Participants
Ethnicity (NIH/OMB) Not Hispanic or Latino	19 Participants n=5 Participants
Ethnicity (NIH/OMB) Unknown or Not Reported	0 Participants n=5 Participants
Race (NIH/OMB) American Indian or Alaska Native	0 Participants n=5 Participants
Race (NIH/OMB) Asian	0 Participants n=5 Participants
Race (NIH/OMB) Native Hawaiian or Other Pacific Islander	0 Participants n=5 Participants
Race (NIH/OMB) Black or African American	13 Participants n=5 Participants
Race (NIH/OMB) White	7 Participants n=5 Participants
Race (NIH/OMB) More than one race	0 Participants n=5 Participants
Race (NIH/OMB) Unknown or Not Reported	3 Participants n=5 Participants
Region of Enrollment United States	23 participants n=5 Participants
Height	175.70 cm STANDARD_DEVIATION 10.53 • n=5 Participants
Weight	86.56 kg STANDARD_DEVIATION 15.46 • n=5 Participants

PRIMARY outcome

Timeframe: 120 hours post-challenge

Population: 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

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

Outcome measures

Outcome measures
Measure	ETEC Strain n=23 Participants Each enrolled subject will receive a single administration of the challenge dose Enterotoxigenic E. coli (ETEC) strain: Challenge strain
Number of Participants With Moderate and Severe Diarrhea	17 participants moderate or severe diarrea

PRIMARY outcome

Timeframe: 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.

Outcome measures

Outcome measures
Measure	ETEC Strain n=23 Participants Each enrolled subject will receive a single administration of the challenge dose Enterotoxigenic E. coli (ETEC) strain: Challenge strain
Subjects Developing Moderate-to-Severe Diarrhea Following Oral Challenge	74 percentage of subject with MSD Interval 51.6 to 89.8

Adverse Events

ETEC Strain

Serious events: 0 serious events

Other events: 14 other events

Deaths: 0 deaths

Serious adverse events

Adverse event data not reported

Other adverse events

Other adverse events
Measure	ETEC Strain n=23 participants at risk Each enrolled subject will receive a single administration of the challenge dose Enterotoxigenic E. coli (ETEC) strain: Challenge strain
Gastrointestinal disorders Abdominal distension	13.0% 3/23 • Number of events 3 • 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 * Adverse events, includes all adverse events observed after challenge, regardless of their relationship to the challenge strain * Serious adverse events (SAEs) occurring during the 6 months of the study (from the time of challenge)
Gastrointestinal disorders Abdominal tenderness	13.0% 3/23 • Number of events 4 • 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 * Adverse events, includes all adverse events observed after challenge, regardless of their relationship to the challenge strain * Serious adverse events (SAEs) occurring during the 6 months of the study (from the time of challenge)
Gastrointestinal disorders Eructation	13.0% 3/23 • Number of events 4 • 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 * Adverse events, includes all adverse events observed after challenge, regardless of their relationship to the challenge strain * Serious adverse events (SAEs) occurring during the 6 months of the study (from the time of challenge)
Gastrointestinal disorders Gastrointestinal sounds abnormal	13.0% 3/23 • Number of events 3 • 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 * Adverse events, includes all adverse events observed after challenge, regardless of their relationship to the challenge strain * Serious adverse events (SAEs) occurring during the 6 months of the study (from the time of challenge)
Gastrointestinal disorders Flatulence	8.7% 2/23 • Number of events 2 • 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 * Adverse events, includes all adverse events observed after challenge, regardless of their relationship to the challenge strain * Serious adverse events (SAEs) occurring during the 6 months of the study (from the time of challenge)
Cardiac disorders Tachycardia	13.0% 3/23 • Number of events 3 • 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 * Adverse events, includes all adverse events observed after challenge, regardless of their relationship to the challenge strain * Serious adverse events (SAEs) occurring during the 6 months of the study (from the time of challenge)
Investigations Blood creatinine increased	4.3% 1/23 • Number of events 1 • 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 * Adverse events, includes all adverse events observed after challenge, regardless of their relationship to the challenge strain * Serious adverse events (SAEs) occurring during the 6 months of the study (from the time of challenge)
Investigations Blood sodium decreased	4.3% 1/23 • Number of events 1 • 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 * Adverse events, includes all adverse events observed after challenge, regardless of their relationship to the challenge strain * Serious adverse events (SAEs) occurring during the 6 months of the study (from the time of challenge)
Investigations Blood urea increased	4.3% 1/23 • Number of events 1 • 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 * Adverse events, includes all adverse events observed after challenge, regardless of their relationship to the challenge strain * Serious adverse events (SAEs) occurring during the 6 months of the study (from the time of challenge)
Gastrointestinal disorders Abdominal pain	8.7% 2/23 • Number of events 2 • 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 * Adverse events, includes all adverse events observed after challenge, regardless of their relationship to the challenge strain * Serious adverse events (SAEs) occurring during the 6 months of the study (from the time of challenge)
Gastrointestinal disorders Abdominal pain upper	4.3% 1/23 • Number of events 1 • 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 * Adverse events, includes all adverse events observed after challenge, regardless of their relationship to the challenge strain * Serious adverse events (SAEs) occurring during the 6 months of the study (from the time of challenge)
Gastrointestinal disorders Dyspesia	8.7% 2/23 • Number of events 2 • 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 * Adverse events, includes all adverse events observed after challenge, regardless of their relationship to the challenge strain * Serious adverse events (SAEs) occurring during the 6 months of the study (from the time of challenge)
Gastrointestinal disorders Gastrooesophageal reflux disease	4.3% 1/23 • Number of events 1 • 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 * Adverse events, includes all adverse events observed after challenge, regardless of their relationship to the challenge strain * Serious adverse events (SAEs) occurring during the 6 months of the study (from the time of challenge)
Gastrointestinal disorders Nausea	4.3% 1/23 • Number of events 2 • 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 * Adverse events, includes all adverse events observed after challenge, regardless of their relationship to the challenge strain * Serious adverse events (SAEs) occurring during the 6 months of the study (from the time of challenge)
Gastrointestinal disorders Vormiting	4.3% 1/23 • Number of events 1 • 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 * Adverse events, includes all adverse events observed after challenge, regardless of their relationship to the challenge strain * Serious adverse events (SAEs) occurring during the 6 months of the study (from the time of challenge)
Investigations Blood presure increased	4.3% 1/23 • Number of events 1 • 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 * Adverse events, includes all adverse events observed after challenge, regardless of their relationship to the challenge strain * Serious adverse events (SAEs) occurring during the 6 months of the study (from the time of challenge)
Investigations White blood cell count increased	4.3% 1/23 • Number of events 1 • 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 * Adverse events, includes all adverse events observed after challenge, regardless of their relationship to the challenge strain * Serious adverse events (SAEs) occurring during the 6 months of the study (from the time of challenge)
Metabolism and nutrition disorders Hyperglycaemia	4.3% 1/23 • Number of events 1 • 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 * Adverse events, includes all adverse events observed after challenge, regardless of their relationship to the challenge strain * Serious adverse events (SAEs) occurring during the 6 months of the study (from the time of challenge)
Metabolism and nutrition disorders Lactic acidosis	4.3% 1/23 • Number of events 1 • 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 * Adverse events, includes all adverse events observed after challenge, regardless of their relationship to the challenge strain * Serious adverse events (SAEs) occurring during the 6 months of the study (from the time of challenge)
Musculoskeletal and connective tissue disorders Muscel spasms	8.7% 2/23 • Number of events 2 • 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 * Adverse events, includes all adverse events observed after challenge, regardless of their relationship to the challenge strain * Serious adverse events (SAEs) occurring during the 6 months of the study (from the time of challenge)
Musculoskeletal and connective tissue disorders Myalgia	4.3% 1/23 • Number of events 1 • 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 * Adverse events, includes all adverse events observed after challenge, regardless of their relationship to the challenge strain * Serious adverse events (SAEs) occurring during the 6 months of the study (from the time of challenge)
Nervous system disorders Headache	26.1% 6/23 • Number of events 6 • 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 * Adverse events, includes all adverse events observed after challenge, regardless of their relationship to the challenge strain * Serious adverse events (SAEs) occurring during the 6 months of the study (from the time of challenge)
Psychiatric disorders Insomnia	4.3% 1/23 • Number of events 1 • 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 * Adverse events, includes all adverse events observed after challenge, regardless of their relationship to the challenge strain * Serious adverse events (SAEs) occurring during the 6 months of the study (from the time of challenge)
Psychiatric disorders Panic attack	4.3% 1/23 • Number of events 1 • 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 * Adverse events, includes all adverse events observed after challenge, regardless of their relationship to the challenge strain * Serious adverse events (SAEs) occurring during the 6 months of the study (from the time of challenge)
Vascular disorders Orthostatic hypotension	4.3% 1/23 • Number of events 1 • 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 * Adverse events, includes all adverse events observed after challenge, regardless of their relationship to the challenge strain * Serious adverse events (SAEs) occurring during the 6 months of the study (from the time of challenge)
Vascular disorders Presyncope	8.7% 2/23 • Number of events 2 • 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 * Adverse events, includes all adverse events observed after challenge, regardless of their relationship to the challenge strain * Serious adverse events (SAEs) occurring during the 6 months of the study (from the time of challenge)

Additional Information

Head of Clinical Development

Scandinavian Biopharma Holding AB / Etvax

Phone: 004684705600

Email: [email protected]

Results disclosure agreements

Principal investigator is a sponsor employee
Publication restrictions are in place