Phase 2b Challenge Study With the Bioconjugate Vaccine Flexyn2a

NCT ID: NCT02646371

Last Updated: 2021-01-27

Basic Information

• Recruitment Status: COMPLETED
• Clinical Phase: PHASE2
• Total Enrollment: 67 participants
• Study Classification: INTERVENTIONAL
• Study Start Date: 2015-12-31
• Study Completion Date: 2017-07-31

Brief Summary

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.

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.

Conditions

Shigellosis

Study Design

• Allocation Method: RANDOMIZED
• Intervention Model: PARALLEL
• Primary Study Purpose: PREVENTION
• Blinding Strategy: TRIPLE

Study Groups

Flexyn2a

2 doses of 10 μg of Flexyn2a will be injected intramuscularly 4 weeks apart

Group Type: ACTIVE_COMPARATOR

Flexyn2a

Intervention Type: BIOLOGICAL

2 doses of 10 μg of Flexyn2a will be injected intramuscularly 4 weeks apart

Placebo

2 doses of TBS solution will be injected intramuscularly 4 weeks apart

Group Type: PLACEBO_COMPARATOR

Placebo

Intervention Type: BIOLOGICAL

2 doses of TBS solution will be injected intramuscularly 4 weeks apart

Interventions

Flexyn2a

2 doses of 10 μg of Flexyn2a will be injected intramuscularly 4 weeks apart

Intervention Type: BIOLOGICAL

Placebo

2 doses of TBS solution will be injected intramuscularly 4 weeks apart

Intervention Type: BIOLOGICAL

Eligibility Criteria

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

• Minimum Eligible Age: 18 Years
• Maximum Eligible Age: 50 Years
• Eligible Sex: ALL
• Accepts Healthy Volunteers: Yes

Sponsors

Johns Hopkins Bloomberg School of Public Health

OTHER

Sponsor Role: collaborator

LimmaTech Biologics AG

INDUSTRY

Sponsor Role: lead

Responsible Party

Responsibility Role: SPONSOR

Principal Investigators

Kawsar R Talaat, MD

Role: PRINCIPAL_INVESTIGATOR

Johns Hopkins Bloomberg School of Public Health

Patricia Martin, PhD

Role: STUDY_DIRECTOR

LimmaTech Biologics AG

Locations

Johns Hopkins Bloomberg School of Public Health, CIR

Baltimore, Maryland, United States

Countries

United States

References

Talaat KR, Alaimo C, Martin P, Bourgeois AL, Dreyer AM, Kaminski RW, Porter CK, Chakraborty S, Clarkson KA, Brubaker J, Elwood D, Frolich R, DeNearing B, Weerts H, Feijoo BL, Halpern J, Sack D, Riddle MS, Fonck VG. Human challenge study with a Shigella bioconjugate vaccine: Analyses of clinical efficacy and correlate of protection. EBioMedicine. 2021 Apr;66:103310. doi: 10.1016/j.ebiom.2021.103310. Epub 2021 Apr 13.

Reference Type: DERIVED

PMID: 33862589 (View on PubMed)

Other Identifiers

SF2A-2B

Identifier Type: -

Identifier Source: org_study_id