Efficacy Study of IM Administered CssBA+dmLT Against Moderate-severe Diarrhea in Human Infection … (NCT06692907) | Clinical Trial Compass
CompletedPhase 2
Efficacy Study of IM Administered CssBA+dmLT Against Moderate-severe Diarrhea in Human Infection Model With ETEC Strain B7A in Healthy Adults
United States72 participantsStarted 2025-03-31
Plain-language summary
The study is designed to evaluate the safety, immunogenicity, and efficacy of the intramuscular administration of a CS6 based vaccine (CssBA) against ETEC co-administered with double mutant labile toxin (dmLT) in preventing moderate-severe diarrhea (MSD) following challenge with ETEC strain B7A in healthy adults. Approximately 72 adult participants, divided into 4 cohorts of 18, will be randomized 1:1 to receive vaccine (45 micrograms CssBA with 0.5 micrograms dmLT) or placebo (normal saline) on an outpatient basis. All participants will receive 3 intramuscular (IM) doses of vaccine or placebo at 3-week intervals (days 1, 22 and 43). Following vaccination, participants will be followed as outpatients for safety using a memory aid from the time of each vaccination through 7 days post each vaccination. Approximately 28 days (plus or minus 1 day) after receipt of the 3rd dose of study agent, participants meeting challenge criteria will be admitted to an inpatient unit and be administered an oral dose of 1 x 10\^10 cfu (colony-forming unit) of ETEC strain B7A. Five days after challenge, participants will be treated with ciprofloxacin, except in cases of known allergy or intolerance. Participants will be discharged from the inpatient unit when they have completed their 3-day antibiotic course and are able to care for themselves. After discharge from the inpatient unit, participants will return for clinic visits and have a phone visit to provide any updates on medication, medical history and AE/SAEs. The primary objectives are: 1) Estimate CssBA+dmLT efficacy in preventing moderate-severe diarrhea (MSD) following challenge with ETEC strain B7A in healthy adults. 2) Evaluate the safety of intramuscular injection of CssBA+dmLT.
Who can participate
Age range
18 Years – 49 Years
Sex
ALL
See this in plain English?
AI-rewrites the medical criteria so a patient or caregiver can understand them. Always confirm with the trial site.
Inclusion criteria
. Non-pregnant, non-breast-feeding adults, age 18 to 49 years (inclusive) at the time of enrollment.
. Willing and able to sign and date informed consent document prior to study procedures.
. Stated willingness to be available for all study visits and comply with all trial procedures throughout the duration of the trial, including adherence to Lifestyle Considerations.
. Participants of childbearing potential must have a negative pregnancy test at study enrollment.
. For participants of childbearing potential\*: agree to use highly effective contraception with heterosexual intercourse for at least 1 month prior to the first vaccination through at least two months after receipt of the challenge agent or last dose of study product if not challenged. True abstinence is also acceptable.
Questions worth asking your doctor
Bring these to your next appointment. They're a starting point for a shared conversation — not a sign you qualify or a recommendation to enrol.
1Based on my diagnosis and history, is this trial worth exploring for me — or is there a standard treatment we should try first?
2What does this trial's phase tell us about how much is already known about its safety and benefit?
3What would taking part actually involve for me — visits, tests, time, and travel?
4What are the known and possible risks or side effects I should weigh, and how would they be monitored?
5If this trial isn't the right fit, what other options or trials would you suggest I look into?
Generated to help you prepare — always confirm anything about your own eligibility and care with the study team and your doctor.
Questions for the trial coordinator
The trial coordinator is the person who runs the study day to day. These cover the practical side — logistics, costs, and what taking part would actually mean for your life. The study team confirms whether you meet the criteria; these are questions to ask, not a sign you qualify.
1What does taking part actually involve week to week — how many visits, where, and how long does each one take?
2What costs are covered by the study, and what might I have to pay for myself, including travel, parking, or time off work?
3What happens during screening, and what happens if the study team confirms I don't meet the criteria after those tests?
4Who pays for the scans, blood work, and other tests the trial requires — the study, my insurance, or me?
5How will being in the trial affect my regular care, and will my own doctor stay informed and involved?
6Can I leave the trial at any point if I change my mind, and what would happen to my care if I do?
A starting point for the conversation — always confirm anything about your own eligibility, costs, and care with the study team and your doctor.
What they're measuring
1
Number and percentage of CssBA+dmLT injected participants experiencing local solicited AEs
Timeframe: Through 7 days after vaccination
2
Number and percentage of CssBA+dmLT injected participants experiencing MAAEs
Timeframe: Through 6 months after last vaccination
3
Number and percentage of CssBA+dmLT injected participants experiencing SAEs
Timeframe: Through 6 months after last vaccination
4
Number and percentage of CssBA+dmLT injected participants experiencing systemic solicited AEs
Timeframe: Through 7 days after vaccination
5
Number and percentage of CssBA+dmLT injected participants experiencing unsolicited AEs
Timeframe: Through Day 71
6
Number and percentage of participants experiencing moderate-severe diarrhea (MSD) with Enterotoxigenic Escherichia coli (ETEC)
Timeframe: Day 70-79
Trial details
NCT IDNCT06692907
SponsorNational Institute of Allergy and Infectious Diseases (NIAID)
. Body mass index (BMI) 19 to less than 40 kg/m\^2 at screening.
. In good health. As determined by medical history and physical examination to evaluate acute or ongoing chronic medical diagnoses/conditions that have been present for at least 90 days, which would affect the assessment of safety of participants and interpretations of the scientific aims of the trial. Chronic medical diagnoses/conditions should be stable for the last 60 days (no hospitalizations, ER, or urgent care for condition or need for supplemental oxygen). This includes no change in chronic prescription medication, dose, or frequency as a result of deterioration of the chronic medical diagnosis/condition in the 60 days before enrollment. Any prescription change that is due to change of health care provider, insurance company, etc., or done for financial reasons, and in the same class of medication, will not be considered a deviation of this inclusion criterion. Any change in prescription medication due to improvement of a disease outcome, as determined by the Principal or sub-Investigator licensed to make medical diagnosis, will not be considered a deviation of this inclusion criterion. Participants may be on chronic or as needed (prn) medications if, in the opinion of the participating site PI or appropriate sub-investigator, they pose no additional risk to participant safety or assessment of reactogenicity and immunogenicity, and do not indicate a worsening of medical diagnosis/condition. Similarly, medication changes subsequent to enrollment and trial vaccination are acceptable provided the change was not precipitated by deterioration in the chronic medical condition, and there is no anticipated additional risk to the participant or interference with the evaluation of responses to trial vaccination.
. Oral temperature is less than 100.4 degrees Fahrenheit (38 degrees Celsius) at the time of enrollment.
Exclusion criteria
. Abnormal stool pattern (fewer than 3 stools per week or more than 3 stools per day) on a regular basis; loose or liquid stools on other than an occasional basis.
. History of microbiologically confirmed ETEC or cholera infection in the last 3 years.
. Symptoms consistent with MSD concurrent with travel to countries where ETEC infection is endemic (refer to MOP section for a list of endemic countries) within 3 years prior to enrollment.
. Vaccination for, ingestion of or occupational handling of ETEC, cholera, or E. coli heat labile toxin within 3 years prior to enrollment.
. Any condition that, in the judgment of the investigator, precludes participation because it could affect participant safety or endpoint evaluation.
. Unable to understand spoken and written English.
. Venous access deemed inadequate for phlebotomy/cannulation needs of the study.
. Have any disease or medical condition that, in the opinion of the Principal or sub-Investigator licensed to make medical diagnosis, is a contraindication to study participation. These include: