Phase 2b Challenge Study With the Bioconjugate Vaccine Flexyn2a

January 7, 2021 updated by: LimmaTech Biologics AG

Phase 2b, Double-blind, Placebo-controlled Efficacy Challenge Study With a Candidate Bioconjugate Vaccine Against Shigella Flexneri 2a

In this proof of concept challenge study, the bioconjugate candidate vaccine Flexyn2a will be tested for its ability to induce an immune response that protects healthy adult volunteers from infection with a wild-type Shigella flexneri 2a strain compared to subjects receiving placebo.

Study Overview

Status

Status

Indicates the current recruitment status or the expanded access status.
Completed

Conditions

Conditions

The disease, disorder, syndrome, illness, or injury that is being studied. On ClinicalTrials.gov, conditions may also include other health-related issues, such as lifespan, quality of life, and health risks.

Intervention / Treatment

Intervention / Treatment

A process or action that is the focus of a clinical study. Interventions include drugs, medical devices, procedures, vaccines, and other products that are either investigational or already available. Interventions can also include noninvasive approaches, such as education or modifying diet and exercise.

Detailed Description

Flexyn2a is a bioconjugate candidate vaccine that is able to induce an humoral immune response specific for the 2a-antigen of Shigella flexneri 2a bacteria. Healthy adult volunteers naïve for Shigella flexneri 2a infections at screening will receive two administrations of 10 micrograms Flexyn2a or placebo 4 weeks apart. Four weeks after the second vaccination, each subject will be challenged with 1500 cfu of the virulent Shigella flexneri 2a strain 2457T. In order to assess the ability of Flexyn2a to protect against infection with this strain, the attack rate of shigellosis in the group vaccinated with Flexyn2a will be compared to the group of the subjects who received placebo injections.

Study Type

Study Type

Describes the nature of a clinical study. Study types include interventional studies (also called clinical trials), observational studies (including patient registries), and expanded access.
Interventional

Enrollment (Actual)

Enrollment

The number of participants in a clinical study. The "anticipated" enrollment is the target number of participants that the researchers need for the study.
67

Phase

Phase

The stage of a clinical trial studying a drug or biological product, based on definitions developed by the U.S. Food and Drug Administration (FDA). The phase is based on the study's objective, the number of participants, and other characteristics. There are five phases: Early Phase 1 (formerly listed as Phase 0), Phase 1, Phase 2, Phase 3, and Phase 4. Not Applicable is used to describe trials without FDA-defined phases, including trials of devices or behavioral interventions.
  • Phase 2

Contacts and Locations

This section provides the contact details for those conducting the study, and information on where this study is being conducted.

Study Locations

  • United States
    • Maryland
      • Baltimore, Maryland, United States, 21205
        • Johns Hopkins Bloomberg School of Public Health, CIR

Participation Criteria

Researchers look for people who fit a certain description, called eligibility criteria. Some examples of these criteria are a person's general health condition or prior treatments.

Eligibility Criteria

Eligibility Criteria

The key requirements that people who want to participate in a clinical study must meet or the characteristics they must have. Eligibility criteria consist of both inclusion criteria (which are required for a person to participate in the study) and exclusion criteria (which prevent a person from participating). Types of eligibility criteria include whether a study accepts healthy volunteers, has age or age group requirements, or is limited by sex.

Ages Eligible for Study

18 years to 50 years (Adult)

Accepts Healthy Volunteers

No

Genders Eligible for Study

All

Description

Inclusion Criteria:

  • Male or female age 18-50 years (inclusive)
  • Good health, without clinically significant medical history or physical examination findings.
  • Negative serum pregnancy test at screening, and negative urine before each vaccination and before challenge for female subjects of childbearing potential.
  • Females of childbearing potential must agree to avoid pregnancy by use of effective contraception. Abstinence is not acceptable as effective contraception. Female subjects unable to bear children must have this documented (e.g. tubal ligation or hysterectomy).
  • 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, knowledge of Shigella-associated illness, and a passing score of 70% or better on a written examination.
  • Availability for the study duration, including all planned follow-up visits.
  • Willingness to refrain from participating in other studies of investigational products until completion of the last study visit.

Exclusion Criteria:

  • Women currently nursing.
  • Presence of a significant medical or psychiatric condition which in the opinion of the investigator precludes participation in the study.
  • Clinically significant abnormalities in screening hematology or serum chemistry as determined by PI or PI in consultation with the research monitor and sponsor.
  • Presence in the serum of HIV antibody, HBs-Ag, or HCV antibody (if confirmed positive by HepC confirmatory test, i.e. RIBA, PCR)
  • Evidence of IgA deficiency (serum IgA < 7 mg/dl or limit of detection of assay).
  • Evidence of current excessive alcohol consumption or drug dependence.
  • Evidence of impaired immune function.
  • BMI <19 and ≥35
  • Recent vaccination or receipt of an investigational product (within 30 days before vaccination and until last study visit).
  • Personal history of an inflammatory arthritis.
  • Positive blood test for HLA-B27.
  • Personal history of irritable bowel syndrome as defined by Rome III criteria.
  • Treatment with immunoglobulins or blood products within 3 months from first candidate vaccine injection.
  • Regularly abnormal stool pattern (fewer than 3 per week or more than 3 per day) or loose or liquid stools
  • Regular use of laxatives, antacids, or other agents to lower stomach acidity.
  • Use of any medication known to affect the immune function (e.g., systemic steroids) within 30 days preceding the first vaccination or planned use during the entire study period.
  • Known allergy to any of the following antibiotics: ciprofloxacin, trimethoprim-sulfamethoxazole or penicillin.
  • Symptoms consistent with Traveler's Diarrhea concurrent with travel to countries where Shigella infection is endemic (most of the developing world) within two years prior to dosing, OR planned travel to endemic countries during the length of the study.
  • Vaccination for or ingestion of Shigella within 3 years prior to vaccination.
  • Use of antibiotics during the 7 days before vaccination and challenge
  • Use of proton pump inhibitors, H2 blockers or antacids within 48 hours prior to challenge.
  • Serum IgG titer to Shigella flexneri 2a LPS ≥ 2500
  • Current occupation involving handling of Shigella bacteria
  • History of allergy to any vaccine or to soy
  • 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

Study Plan

This section provides details of the study plan, including how the study is designed and what the study is measuring.

How is the study designed?

Design Details

  • Primary Purpose: Prevention
  • Allocation: Randomized
  • Interventional Model: Parallel Assignment
  • Masking: Triple

Arms and Interventions

Participant Group / Arm

Participant Group / Arm

A group or subgroup of participants in a clinical trial that receives a specific intervention/treatment, or no intervention, according to the trial's protocol.
Intervention / Treatment

Intervention / Treatment

A process or action that is the focus of a clinical study. Interventions include drugs, medical devices, procedures, vaccines, and other products that are either investigational or already available. Interventions can also include noninvasive approaches, such as education or modifying diet and exercise.
Active Comparator: Flexyn2a
2 doses of 10 μg of Flexyn2a will be injected intramuscularly 4 weeks apart
Biological: Flexyn2a
2 doses of 10 μg of Flexyn2a will be injected intramuscularly 4 weeks apart
Placebo Comparator: Placebo
2 doses of TBS solution will be injected intramuscularly 4 weeks apart
Biological: Placebo
2 doses of TBS solution will be injected intramuscularly 4 weeks apart

What is the study measuring?

Primary Outcome Measures

Primary Outcome Measures

In a clinical study's protocol, the planned outcome measure that is the most important for evaluating the effect of an intervention/treatment. Most clinical studies have one primary outcome measure, but some have more than one.
Outcome Measure
Measure Description
Time Frame
Attack Rate of Shigellosis in Vaccinated Subjects.
Time Frame: Between Day 56 and Day 64
The attack rate of shigellosis after challenge in vaccine group versus in placebo group was analyzed.
Between Day 56 and Day 64

Collaborators and Investigators

This is where you will find people and organizations involved with this study.

Sponsor

Sponsor

The organization or person who initiates the study and who has authority and control over the study.
LimmaTech Biologics AG

Collaborators

Collaborators

An organization other than the sponsor that provides support for a clinical study. This support may include activities related to funding, design, implementation, data analysis, or reporting.
Johns Hopkins Bloomberg School of Public Health

Investigators

Investigators

A researcher involved in a clinical study. Related terms include site principal investigator, site sub-investigator, study chair, study director, and study principal investigator.
  • Study Director: Patricia Martin, PhD, LimmaTech Biologics AG

Publications and helpful links

The person responsible for entering information about the study voluntarily provides these publications. These may be about anything related to the study.

General Publications

Study record dates

These dates track the progress of study record and summary results submissions to ClinicalTrials.gov. Study records and reported results are reviewed by the National Library of Medicine (NLM) to make sure they meet specific quality control standards before being posted on the public website.

Study Major Dates

Study Start (Actual)

Study Start

The actual date on which the first participant was enrolled in a clinical study. The "anticipated" study start date is the date that the researchers think will be the study start date.
December 1, 2015

Primary Completion (Actual)

Primary Completion

The date on which the last participant in a clinical study was examined or received an intervention to collect final data for the primary outcome measure. Whether the clinical study ended according to the protocol or was terminated does not affect this date. For clinical studies with more than one primary outcome measure with different completion dates, this term refers to the date on which data collection is completed for all the primary outcome measures. The "anticipated" primary completion date is the date that the researchers think will be the primary completion date for the study.
September 1, 2016

Study Completion (Actual)

Study Completion

The date on which the last participant in a clinical study was examined or received an intervention/treatment to collect final data for the primary outcome measures, secondary outcome measures, and adverse events (that is, the last participant's last visit). The "anticipated" study completion date is the date that the researchers think will be the study completion date.
July 1, 2017

Study Registration Dates

First Submitted

First Submitted

The date on which the study sponsor or investigator first submitted a study record to ClinicalTrials.gov. There is typically a delay of a few days between the first submitted date and the record's availability on ClinicalTrials.gov (the first posted date).
December 23, 2015

First Submitted That Met QC Criteria

First Submitted That Met QC Criteria

The date on which the study sponsor or investigator first submits a study record that is consistent with National Library of Medicine (NLM) quality control (QC) review criteria. The sponsor or investigator may need to revise and submit a study record one or more times before NLM's QC review criteria are met. It is the responsibility of the sponsor or investigator to ensure that the study record is consistent with the NLM QC review criteria.
January 4, 2016

First Posted (Estimate)

First Posted

The date on which the study record was first available on ClinicalTrials.gov after National Library of Medicine (NLM) quality control (QC) review has concluded. There is typically a delay of a few days between the date the study sponsor or investigator submitted the study record and the first posted date.
January 5, 2016

Study Record Updates

Last Update Posted (Actual)

Last Update Posted

The most recent date on which changes to a study record were made available on ClinicalTrials.gov. There may be a delay between when the changes were submitted to ClinicalTrials.gov by the study's sponsor or investigator (the last update submitted date) and the last update posted date.
January 27, 2021

Last Update Submitted That Met QC Criteria

Last Update Submitted That Met QC Criteria

The most recent date on which the study sponsor or investigator submitted changes to a study record that are consistent with National Library of Medicine (NLM) quality control (QC) review criteria. It is the responsibility of the sponsor or investigator to ensure that the study record is consistent with the NLM QC review criteria.
January 7, 2021

Last Verified

Last Verified

The most recent date on which the study sponsor or investigator confirmed the information about a clinical study on ClinicalTrials.gov as accurate and current. If a study with a recruitment status of recruiting; not yet recruiting; or active, not recruiting has not been confirmed within the past 2 years, the study's recruitment status is shown as unknown.
January 1, 2021

More Information

Terms related to this study

Additional Relevant MeSH Terms

Other Study ID Numbers

Other Study ID Numbers

Identifiers or ID numbers other than the NCT number that are assigned to a clinical study by the study's sponsor, funders, or others. These numbers may include unique identifiers from other trial registries and National Institutes of Health grant numbers.
  • SF2A-2B

Drug and device information, study documents

Studies a U.S. FDA-regulated drug product

No

Studies a U.S. FDA-regulated device product

No

product manufactured in and exported from the U.S.

No

This information was retrieved directly from the website clinicaltrials.gov without any changes. If you have any requests to change, remove or update your study details, please contact register@clinicaltrials.gov. As soon as a change is implemented on clinicaltrials.gov, this will be updated automatically on our website as well.

Cookie Settings

We use cookies to ensure that we give you the best experience on our website. For more details carefully read our Privacy and Cookies Policy. ...>>>You can change your preferences or withdraw your consent at any time by deleting the cookies from your website or computer as described in the policy. Please accept it and choose your preferences by ticking the corresponding boxes in the "Manage Settings" section below. Please carefully read our Terms of Service before you proceed with using any part of this website.
«Manage Settings