Healthy Volunteers (Prevention of Diarrheal Disease Due to Infection With Enterotoxigenic E. Coli ) Clinical Trial
A Phase 2 Immunological Bridging Study Assessing the Non-inferiority of a New Formulation of ETVAX®. A Prospective Double-blind, Randomized Study in Healthy Volunteers.
This is a phase 2,prospective double-blind, randomized, parallel-group study with the aim to demonstrate non-inferiority, in terms of immunogenicity, between the wet formulation and a newly developed partially dried formulation of selected components of ETVAX.
This is a phase 2, prospective double-blind, randomized, parallel-group study with the aim to demonstrate non-inferiority, in terms of immunogenicity, between the wet formulation and a newly developed partially dried formulation of selected components of ETVAX.. A total number of 126 subjects will be included in each arm of the study, i.e. 252 subjects in total. Assuming a 10% dropout rate the target number of subjects to be recruited per study arm is therefore 140, i.e. 280 subjects in total. Healthy volunteers between 18-50 years will be eligible for enrolment into the study. Eligible subjects will be randomized on Day 1 (Visit 2) to receive either of the two oral formulations of ETVAX (1:1) and consecutively included the study. The treatment allocation (Wet formulation/Partially dried formulation) will be double-blind. The study subjects will receive two oral doses, two weeks apart (Day 1/Visit 2 and Day 15 /Visit 3).The dosing will occur at the clinic (CTC in Gothenburg, Sweden). A follow-up visit will be performed 7 days after the last (second) dose in all study subjects The primary endpoint to be measured for each patient in the study is response (yes/no) to a vaccine. A vaccine responder will be defined by a ≥2-fold increase in IgA and/or IgG antibody levels against LTB in serum between post- compared to pre-immunization samples. The response rates (seroconversion rates) of IgA and/or IgG anti-LTB antibodies in serum will be derived and compared between the two treatment groups. The secondary endpoint to be measured for each patient in the study is the occurrence of solicited symptoms for six days after each vaccination (day of vaccination and five subsequent days). Exploratory analyses will be done to evaluate if ETVAX vaccination induces circulating antigen specific memory B- and/or T cells that can be assessed using recently established laboratory assays. For the exploratory analyses, subgroups of subjects (n=20-40, evenly distributed between the two treatment arms) will participate in additional follow-up visits 5± 1, 30± 7 and 90± 14 days after the second dose. Blood samples will be collected on all exploratory visits. The extra visits and analyses for exploratory analyses may continue after the main part of the study has been completed and the database locked. ;