Last updated: 12/22/2025 06:31:23

A study on the safety and immune responses to the GVGH altSonflex1-2-3 vaccine against shigellosis in adults, children, and infants

GSK study ID
212149
Clinicaltrials.gov ID
EudraCT ID
EU CT Number
Not applicable
Trial status
Study complete
Study complete
Overview
Eligibility
Locations
Study documents
Results summary
Plain language summaries
Additional information

Trial overview

Official title: A staged Phase I/II observer-blind, randomised, controlled, multi-country study to evaluate the safety, reactogenicity, and immune responses to the GVGH altSonflex1-2-3 vaccine against S. sonnei and S. flexneri, serotypes 1b, 2a, and 3a, in adults in Europe (Stage 1) followed by age de-escalation from adults to children and infants, and dose-finding in infants in Africa (Stage 2)
Trial description: The aim of the current clinical study is to evaluate, for the first time in humans (FTIH), the safety and immunogenicity of the altSonflex1-2-3 candidate vaccine against S. sonnei and S. flexneri serotypes 1b, 2a, and 3a. The vaccine will be first administered in adults 18 to 50 years of age in Europe. Subsequently, the vaccine will be administered to a shigellosis-endemic population in Africa, first in adults 18 to 50 years of age, then in children 24 to 59 months of age, finally in infants 9 months of age. Infants will also receive a third vaccination. Three different doses of the vaccine [low (Dose A), medium (Dose B), and high (Dose C) amounts of antigen] will be evaluated using an age de-escalation approach (from least vulnerable adult population to most vulnerable paediatric population). The results of this study will allow the selection of the most appropriate dose for further vaccine development in infants 9 months of age, which is the main target age group for this vaccine.
Primary purpose:
Prevention
Trial design:
Sequential Assignment
Masking:
Quadruple (Participant, Care Provider, Investigator, Outcomes Assessor)
Allocation:
Randomized
Primary outcomes:

Anti-serotype specific Shigella lipopolysaccharide (LPS)/O-Antigen (OAg) serum immunoglobulin G (IgG) geometric mean concentrations (GMCs) in infants 9 months of age in Africa

Timeframe: At Day 281 (28 days after the third study intervention administration)

Number of adults 18 to 50 years of age in Europe with solicited administration site events

Timeframe: During 7 days after each study intervention administration (study interventions administered at Day 1 and Day 85/Day 169)

Number of adults 18 to 50 years of age in Europe with solicited systemic events

Timeframe: During 7 days after each study intervention administration (study interventions administered at Day 1 and Day 85/Day 169)

Number of adults 18 to 50 years of age in Europe with unsolicited adverse events (AEs)

Timeframe: During 28 days after each study intervention administration (study interventions administered at Day 1 and Day 85/Day 169)

Number of adults 18 to 50 years of age in Europe with serious adverse events (SAEs)

Timeframe: During the entire study participation period [Day 1 to Day 113 (for ST1_Adults_Placebo_GR1 and ST1_Adults_Dose C_GR1 groups)/Day 197 (for ST1_Adults_Placebo_GR2 and ST1_Adults_Dose C_GR2 groups)

Number of adults 18 to 50 years of age in Europe with deviations from normal values of haematological, renal, and hepatic panel test results at Day 8 (7 days after the first study intervention administration)

Timeframe: At Day 8 (7 days after the first study intervention administration)

Number of adults 18 to 50 years of age in Europe with deviations from normal values of haematological, renal, and hepatic panel test results at Day 92/Day 176 (7 days after the second study intervention administration)

Timeframe: At Day 92 (for ST1_Adults_Placebo_GR1 and ST1_Adults_Dose C_GR1 groups)/Day 176 (for ST1_Adults_Placebo_GR2 and ST1_Adults_Dose C_GR2 groups) (7 days after the second study intervention administration)

Number of adults 18 to 50 years of age in Africa with solicited administration site events

Timeframe: During 7 days after each study intervention administration (study interventions administered at Day 1 and Day 85)

Number of adults 18 to 50 years of age in Africa with solicited systemic events

Timeframe: During 7 days after each study intervention administration (study interventions administered at Day 1 and Day 85)

Number of adults 18 to 50 years of age in Africa with unsolicited AEs

Timeframe: During 28 days after each study intervention administration (study interventions administered at Day 1 and Day 85)

Number of adults 18 to 50 years of age in Africa with SAEs

Timeframe: During the entire study participation (Day 1 to Day 113)

Number of adults 18 to 50 years of age in Africa with deviations from normal values of haematological, renal, and hepatic panel test results at Day 8 (7 days after the first study intervention administration)

Timeframe: At Day 8 (7 days after the first study intervention administration)

Number of adults 18 to 50 years of age in Africa with deviations from normal values of haematological, renal, and hepatic panel test results at Day 92 (7 days after the second study intervention administration)

Timeframe: At Day 92 (7 days after the second study intervention administration)

Number of children 24 to 59 months of age in Africa with solicited administration site events

Timeframe: During 7 days after each study intervention administration (study interventions administered at Day 1 and Day 85)

Number of children 24 to 59 months of age in Africa with solicited systemic events

Timeframe: During 7 days after each study intervention administration (study interventions administered at Day 1 and Day 85)

Number of children 24 to 59 months of age in Africa with unsolicited AEs

Timeframe: During 28 days after each study intervention administration (study interventions administered on Day 1 and Day 85)

Number of children 24 to 59 months of age in Africa with SAEs

Timeframe: During the entire study participation period (Day 1 to Day 113)

Number of children 24 to 59 months of age in Africa with deviations from normal values of haematological, renal, and hepatic panel test results at Day 8 (7 days after the first study intervention administration)

Timeframe: At Day 8 (7 days after the first study intervention administration)

Number of children 24 to 59 months of age in Africa with deviations from normal values of haematological, renal, and hepatic panel test results at Day 92 (7 days after the second study intervention administration)

Timeframe: At Day 92 (7 days after the second study intervention administration)

Number of infants 9 months of age in Africa with solicited administration site events

Timeframe: During 7 days after each study intervention administration (study interventions administered at Day 1, Day 85 and Day 253)

Number of infants 9 months of age in Africa with solicited systemic events

Timeframe: During 7 days after each study intervention administration (study interventions administered at Day 1, Day 85 and Day 253)

Number of infants 9 months of age in Africa with unsolicited AEs

Timeframe: During 28 days after each study intervention administration (study intervention administered at Day 1, Day 85 and Day 253)

Number of infants 9 months of age in Africa with SAEs

Timeframe: During the entire study participation period (Day 1 to Day 281)

Number of infants 9 months of age in Africa with deviations from normal values of haematological, renal, and hepatic panel test results at Day 8 (7 days after the first study intervention administration)

Timeframe: At Day 8 (7 days after the first study intervention administration)

Number of infants 9 months of age in Africa with deviations from normal values of haematological, renal, and hepatic panel test results at Day 92 (7 days after the second study intervention administration)

Timeframe: At Day 92 (7 days after the second study intervention administration)

Number of infants 9 months of age in Africa with deviations from normal values of haematological, renal, and hepatic panel test results at Day 260 (7 days after the third study intervention administration)

Timeframe: At Day 260 (7 days after the third study intervention administration)

Secondary outcomes:

Anti-serotype specific Shigella LPS/OAg serum IgG GMCs in adults 18 to 50 years of age in Europe

Timeframe: At Day 1 and Day 85/Day 169 (before each study intervention administration), at Day 15 (14 days after the first study intervention administration) and at Day 29 and Day 113/Day197 (28 days after each study intervention administration)

Anti-serotype specific Shigella LPS/OAg serum IgG GMCs in adults 18 to 50 years of age in Africa

Timeframe: At Day 1 and Day 85 (before each study intervention administration) and at Day 29 and Day 113 (28 days after each study intervention administration)

Anti-serotype specific Shigella LPS/OAg serum IgG GMCs in children 24 to 59 months of age in Africa

Timeframe: At Day 1 and Day 85 (before each study intervention administration) and at Day 29 and Day 113 (28 days after each study intervention administration)

Anti-serotype specific Shigella LPS/OAg serum IgG GMCs in infants 9 months of age in Africa

Timeframe: At Day 1, Day 85 and Day 253 (before each study intervention administration) and at Day 29, Day 113 and Day 281 (28 days after each study intervention administration)

Number of adults 18 to 50 years of age in Europe achieving a GVGH ELISA level equivalent to ≥1:800 titer against S. sonnei LPS/OAg

Timeframe: At Day 1 and Day 85/Day 169 (before each study intervention administration), at Day 15 (14 days after the first study intervention administration) and at Day 29 and Day 113/Day 197 (28 days after each study intervention administration)

Number of adults 18 to 50 years of age in Africa achieving a GVGH ELISA level equivalent to ≥1:800 titer against S. sonnei LPS/OAg

Timeframe: At Day 1 and Day 85 (before each study intervention administration) and at Day 29 and Day 113 (28 days after each study intervention administration)

Number of children 24 to 59 months of age in Africa achieving a GVGH ELISA level equivalent to ≥1:800 titer against S. sonnei LPS/OAg

Timeframe: At Day 1 and Day 85 (before each study intervention administration) and at Day 29 and Day 113 (28 days after each study intervention administration)

Number of infants 9 months of age in Africa achieving a GVGH ELISA level equivalent to ≥1:800 titer against S. sonnei LPS/OAg

Timeframe: At Day 1, Day 85 and Day 253 (before each study intervention administration) and at Day 29, Day 113 and Day 281 (28 days after each study intervention administration)

Number of adults 18 to 50 years of age in Europe achieving a GVGH ELISA level equivalent to ≥1:1600 titer against S. sonnei LPS/OAg

Timeframe: At Day 1 and Day 85/Day 169 (before each study intervention administration), at Day 15 (14 days after the first study intervention administration) and at Day 29 and Day 113/Day 197 (28 days after each study intervention administration)

Number of adults 18 to 50 years of age in Africa achieving a GVGH ELISA level equivalent to ≥1:1600 titer against S. sonnei LPS/OAg

Timeframe: At Day 1 and Day 85 (before each study intervention administration) and at Day 29 and Day 113 (28 days after each study intervention administration)

Number of children 24 to 59 months of age in Africa achieving a GVGH ELISA level equivalent to ≥1:1600 titer against S. sonnei LPS/OAg

Timeframe: At Day 1 and Day 85 (before each study intervention administration) and at Day 29 and Day 113 (28 days after each study intervention administration)

Number of infants 9 months of age in Africa achieving a GVGH ELISA level equivalent to ≥1:1600 titer against S. sonnei LPS/OAg

Timeframe: At Day 1, Day 85 and Day 253 (before each study intervention administration) and at Day 29, Day 113 and Day 281 (28 days after each study intervention administration)

Number of adults 18 to 50 years of age in Europe showing at least a 4-fold increase in anti-serotype specific Shigella LPS/OAg serum IgG concentrations, as measured by GVGH ELISA

Timeframe: At Day 15 (14 days after first study intervention administration) and at Day 29 and Day 113/197 (28 days after each study intervention administration) compared to Day 1 and Day 85/Day 169 (baseline)

Number of adults 18 to 50 years of age in Africa showing at least a 4-fold increase in anti-serotype specific Shigella LPS/OAg serum IgG concentrations, as measured by GVGH ELISA

Timeframe: At Day 29 and Day 113 (28 days after each study intervention administration) compared to Day 1 and Day 85 (baseline)

Number of children 24 to 59 months of age in Africa showing at least a 4-fold increase in anti-serotype specific Shigella LPS/OAg serum IgG concentrations, as measured by GVGH ELISA

Timeframe: At Day 29 and Day 113 (28 days after each study intervention administration) compared to Day 1 and Day 85 (baseline)

Number of infants 9 months of age in Africa showing at least a 4-fold increase in anti-serotype specific Shigella LPS/OAg serum IgG concentrations, as measured by GVGH ELISA

Timeframe: At Day 29, Day 113 and Day 281 (28 days after each study intervention administration) compared to Day 1, Day 85 and Day 253 (baseline)

Anti-measles IgG concentrations in infants 9 months of age in the dose-finding groups in Africa

Timeframe: At Day 1 (before the first MR-VAC dose administration) and Day 281 (28 days after the second MR-VAC dose administration)

Anti-rubella IgG concentrations in infants 9 months of age in the dose-finding groups in Africa

Timeframe: At Day 1 (before the first MR-VAC dose administration) and Day 281 (28 days after the second MR-VAC dose administration)

Number of infants 9 months of age in the dose-finding groups in Africa achieving anti-measles IgG concentrations of ≥150 mIU/mL and ≥200 mIU/mL

Timeframe: At Day 281 (28 days after the second MR-VAC dose administration)

Number of infants 9 months of age in the dose-finding groups in Africa achieving anti-rubella IgG concentrations of ≥4 IU/mL and ≥10 IU/mL

Timeframe: At Day 281 (28 days after the second MR-VAC dose administration)

Interventions:
  • Drug: altSonflex Placebo
  • Biological/vaccine: altSonflex1-2-3 Dose C
  • Biological/vaccine: altSonflex1-2-3 Dose B
  • Biological/vaccine: altSonflex1-2-3 Dose A
  • Biological/vaccine: GSK’s Meningococcal A, C, Y and W-135 conjugate vaccine
  • Combination product: GSK’s Tetanus toxoid, reduced diphtheria toxoid and acellular pertussis vaccine
  • Combination product: GSK’s Diphtheria, tetanus, pertussis, hepatitis B, poliomyelitis (inactivated), and Haemophilus influenzae type b vaccine
  • Combination product: Sanofi Pasteur’s Typhoid Vi polysaccharide vaccine
  • Biological/vaccine: Serum Institute of India’s Measles and rubella vaccine
  • Enrollment:
    551
    Primary completion date:
    2025-24-06
    Observational study model:
    Not applicable
    Time perspective:
    Not applicable
    Clinical publications:
    Not applicable
    Medical condition
    Diarrhoea
    Product
    Not applicable
    Collaborators
    Not applicable
    Study date(s)
    October 2021 to June 2025
    Type
    Interventional
    Phase
    1

    Participation criteria

    Sex
    Female & Male
    Age
    9 Months - 50 Years
    Accepts healthy volunteers
    Yes
    • All participants:
    • Participants and/or participants’ parent(s)/legally acceptable representative(s) LAR(s), who, in the opinion of the investigator, can and will comply with the requirements of the protocol (e.g. completion of the diary cards, return for follow-up visits).
    • All participants:
    • Known exposure to Shigella during lifetime of the participant as confirmed during interview with the participant or documented by patient records (e.g., history of microbiologically-confirmed Shigella infection), recent travel* (within 2 years) to a country where Shigella or other enteric infections are endemic, or recent occupation* (within 3 years) involving Shigella species.

    Trial location(s)

    Location
    Status
    Contact us
    Contact us
    Location
    GSK Investigational Site
    Gent, Belgium, 9000
    Status
    Study Complete
    Location
    GSK Investigational Site
    Kericho, Kenya, 20200
    Status
    Study Complete

    Study documents

    No study documents available.

    Results overview

    Study Results yet to be posted

    Recruitment status
    Study complete
    Actual primary completion date
    2025-24-06
    Actual study completion date
    2025-24-06

    Plain language summaries

    Summary of results in plain language
    Available language(s): English, Dutch (Belgium), Kiswahili

    To view plain language summaries on trialsummaries.com click here.

    Additional information about the trial

    Additional information
    Not applicable
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