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AltSonflex1-2-3 High Dose

Phase 2

Diarrhoea | Monoclonal antibody | Gastrointestinal |GSK plc|Trials Updated: Jun 22, 2026

AltSonflex1-2-3 High Dose development status

Highest phase Phase 2
Registered trials 1 across 1 sponsor since Oct 2021

AltSonflex1-2-3 High Dose target and mechanism

ModalityMonoclonal antibody

Also known as AltSonflex1-2-3

Success Probability

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Market & Valuation

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Trial Design

RandomizedDouble-BlindPLACEBO_CONTROLLEDDMC
Total Trials3
Total Enrollment1,279

FDA Designations

No designations recorded

AltSonflex1-2-3 High Dose clinical trials

AltSonflex1-2-3 High Dose · 3 trials · 1 indication

Phase 2 2Phase 1 1
NCT07320716Long-Term Immunogenicity of the altSonflex1-2-3 Shigella Vaccine in African ChildrenDiarrhoea
NOT YET_RECRUITING528 Analytics
NCT06663436A Study on the Immune Response and Safety of a Multicomponent Shigella Vaccine in Preventing Shigellosis in InfantsDiarrhoea
COMPLETED200 Analytics
PHASE2NOT YET_RECRUITING
Long-Term Immunogenicity of the altSonflex1-2-3 Shigella Vaccine in African Children
DiarrhoeaUnlock trial analytics
PHASE2COMPLETED
A Study on the Immune Response and Safety of a Multicomponent Shigella Vaccine in Preventing Shigellosis in Infants
DiarrhoeaUnlock trial analytics

Study Endpoints

Primary Endpoints

Anti-serotype specific Shigella lipopolysaccharide (LPS)/O-antigen (OAg) serum immunoglobulin G (IgG), as measured by GVGH enzyme-linked immunosorbent assay . (ELISA)
At Visit 1 of the current study (12 months after last vaccination in the parent studies)

S. sonnei, S. flexneri 1b, S. flexneri 2a, and S. flexneri 3a serotypes will be tested.

Anti-serotype specific Shigella LPS/OAg serum IgG, as measured by GVGH ELISA
At Visit 2 of the current study (24 months after last vaccination in the parent studies)

S. sonnei, S. flexneri 1b, S. flexneri 2a, and S. flexneri 3a serotypes will be tested.

Geometric mean titers (GMTs) of anti-serotype-specific Shigella lipopolysaccharides/O-antigen (LPS/OAg) serum Immunoglobulin G (IgG)
Day 1 (before administration of Dose 1)
GMTs of anti-serotype-specific Shigella LPS/OAg serum IgG
Day 169 (before administration of Dose 2)
Geometric mean concentrations (GMCs) of anti-serotype-specific Shigella LPS/OAg serum IgG
Day 1 (before administration of Dose 1)
GMCs of anti-serotype-specific Shigella LPS/OAg serum IgG
Day 169 (before administration of Dose 2)
Number of infants with at least a 4-fold increase in anti-serotype-specific Shigella LPS/OAg serum IgG
Day 29 compared with baseline (Day 1)
Stage 2: Geometric Mean Concentrations (GMCs) of Anti-serotype Specific Shigella Lipopolysaccharide (LPS)/O-Antigen (OAg) Serum Immunoglobulin G (IgG) in Participants 9 Months of Age in Africa
At Day 281 (28 days after the third study intervention)

Anti-serotype specific Shigella LPS/OAg serum IgG GMCs were measured by enzyme-linked immunosorbent assay (ELISA) and expressed in ELISA units per milliliter (EU/mL) of serum. Four serotypes were tested. Due to the fact, that the Per protocol set (PPS) for Stage 2 Infants - dose finding cohort had less than the 72 participants per group defined in the protocol as a minimum number of participants to ensure power of the analysis, the Stage 2 Infants Safety cohort and Dose-finding cohort were pooled for the statistical analysis as per the Statistical Analysis Plan. As per protocol, statistical analysis was performed only for the S. sonnei serotype, comparing Stage 2 Infants: Pooled groups (medium vs low dose); and Stage 2 Infants Dose-finding groups (high vs low dose). The objective of this outcome measure is to identify the preferred dose of each component of the altSonflex1-2-3 vaccine for infants 9 months of age in Africa, therefore control groups were not analyzed.

Stage 1: Number of Participants 18 to 50 Years of Age in Europe With Solicited Administration Site Events
Within 7 days after each study intervention (administered at Day 1, Day 85 and Day 169 [depending on the vaccination schedule])

The solicited administration site events assessed were erythema, pain, and swelling.

Stage 1: Number of Adults 18 to 50 Years of Age in Europe With Solicited Systemic Events
Within 7 days after each study intervention (administered at Day 1, Day 85 and Day 169 [depending on the vaccination schedule])

The solicited systemic event assessed was fever. Fever is defined as temperature equal to or above (=\>) 38.0°C.

Stage 1: Number of Participants 18 to 50 Years of Age in Europe With Unsolicited Adverse Events (AEs)
Within 28 days after each study intervention (administered at at Day 1, Day 85 and Day 169 [depending on the vaccination schedule])

An unsolicited AE is defined as an AE reported in addition to those solicited during the clinical study. Also, any 'solicited' symptom with onset outside the specified period of follow-up for solicited symptoms is reported as an unsolicited adverse event.

Stage 1: Number of Participants 18 to 50 Years of Age in Europe With Serious Adverse Events (SAEs)
From Day 1 to Day 113 and/or Day 197

An SAE is defined as any untoward medical occurrence that results in death, is life-threatening, requires inpatient hospitalization or prolongation of existing hospitalization, results in disability/incapacity, is a congenital anomaly/birth defect in the offspring of a study participant, results in abnormal pregnancy outcomes or any other situation based on appropriate medical or scientific judgement.

Stage 1: Number of Participants 18 to 50 Years of Age in Europe With Deviations From Normal Values of Haematological, Renal, and Hepatic Panel Test Results After First Study Intervention
At Day 8

Panel tests include measures of alanine aminotransferase (ALT), aspartate aminotransferase (AST), creatinine, basophils, eosinophils, erythrocytes, haematocrit, haemoglobin, lymphocytes, monocytes, neutrophils, platelets and white blood cells (WBC). Categories reported when comparing Day 1 (baseline) and normal range hematological, renal and hepatic laboratory results are defined as follows: \<parameter\>,\<range at baseline\>,\<range at timing\>, where range is being classified as Below = value below; Within = value within; and Above = value above the laboratory reference range defined for the specified visit and laboratory parameter.

Stage 1: Number of Participants 18 to 50 Years of Age in Europe With Deviations From Normal Values of Haematological, Renal, and Hepatic Panel Test Results After Second Study Intervention
At Day 92 (Stage 1 Adults: altSonflex1-2-3 High Dose Group 1), at Day 176 (Stage 1 Adults: altSonflex1-2-3 High Dose Group 2) and at Day 92/Day 176 (Stage 1 Adults: Placebo Group)

Panel tests include measures of ALT, AST, creatinine, basophils, eosinophils, erythrocytes, haematocrit, haemoglobin, lymphocytes, monocytes, neutrophils, platelets and WBC. Categories reported when comparing Day 85/Day 169 (baseline) and normal range hematological, renal and hepatic laboratory results are defined as follows: \<parameter\>,\<range at baseline\>,\<range at timing\>, where range is being classified as Below = value below; Within = value within; and Above = value above the laboratory reference range defined for the specified visit and laboratory parameter.

Stage 2: Number of Participants 18 to 50 Years of Age in Africa With Solicited Administration Site Events
Within 7 days after each study intervention (administered at Day 1 and Day 85)

The solicited administration site events assessed were pain, erythema, and swelling.

Stage 2: Number of Participants 18 to 50 Years of Age in Africa With Solicited Systemic Events
Within 7 days after each study intervention (administered at Day 1 and Day 85)

The solicited systemic event assessed was fever. Fever is defined as temperature equal to or above (=\>) 38.0°C.

Stage 2: Number of Participants 18 to 50 Years of Age in Africa With Unsolicited Adverse Events (AEs)
Within 28 days after each study intervention (administered at Day 1 and Day 85)

An unsolicited AE is defined as an AE reported in addition to those solicited during the clinical study. Also, any 'solicited' symptom with onset outside the specified period of follow-up for solicited symptoms is reported as an unsolicited adverse event.

Stage 2: Number of Participants 18 to 50 Years of Age in Africa With Serious Adverse Events (SAEs)
From Day 1 to Day 113

An SAE is defined as any untoward medical occurrence that results in death, is life-threatening, requires inpatient hospitalization or prolongation of existing hospitalization, results in disability/incapacity, is a congenital anomaly/birth defect in the offspring of a study participant, results in abnormal pregnancy outcomes or any other situation based on appropriate medical or scientific judgement.

Stage 2: Number of Participants 18 to 50 Years of Age in Africa With Deviations From Normal Values of Haematological, Renal, and Hepatic Panel Test Results After First Study Intervention
At Day 8

Panel tests include measures of ALT, AST, creatinine, basophils, eosinophils, erythrocytes, haematocrit, haemoglobin, lymphocytes, monocytes, neutrophils, platelets and WBC. Categories reported when comparing Day 1 (baseline) and normal range hematological, renal and hepatic laboratory results are defined as follows: \<parameter\>,\<range at baseline\>,\<range at timing\>, where range is being classified as Below = value below; Within = value within; and Above = value above the laboratory reference range defined for the specified visit and laboratory parameter.

Stage 2: Number of Participants 18 to 50 Years of Age in Africa With Deviations From Normal Values of Haematological, Renal, and Hepatic Panel Test Results After Second Study Intervention
At Day 92

Panel tests include measures of ALT, AST, creatinine, basophils, eosinophils, erythrocytes, haematocrit, haemoglobin, lymphocytes, monocytes, neutrophils, platelets and WBC. Categories reported when comparing Day 85 (baseline) and normal range hematological, renal and hepatic laboratory results are defined as follows: \<parameter\>,\<range at baseline\>,\<range at timing\>, where range is being classified as Below = value below; Within = value within; and Above = value above the laboratory reference range defined for the specified visit and laboratory parameter.

Stage 2: Number of Participants 24 to 59 Months of Age in Africa With Solicited Administration Site Events
Within 7 days after each study intervention (administered at Day 1 and Day 85)

The solicited administration site events assessed were erythema, pain, and swelling.

Stage 2: Number of Participants 24 to 59 Months of Age in Africa With Solicited Systemic Events
Within 7 days after each study intervention (administered at Day 1 and Day 85)

The solicited systemic event assessed was fever. Fever is defined as temperature equal to or above (=\>) 38.0°C.

Stage 2: Number of Participants 24 to 59 Months of Age in Africa With Unsolicited Adverse Events (AEs)
Within 28 days after each study intervention (administered at Day 1 and Day 85)

An unsolicited AE is defined as an AE reported in addition to those solicited during the clinical study. Also, any 'solicited' symptom with onset outside the specified period of follow-up for solicited symptoms is reported as an unsolicited adverse event.

Stage 2: Number of Participants 24 to 59 Months of Age in Africa With Serious Adverse Events (SAEs)
From Day 1 to Day 113

An SAE is defined as any untoward medical occurrence that results in death, is life-threatening, requires inpatient hospitalization or prolongation of existing hospitalization, results in disability/incapacity, is a congenital anomaly/birth defect in the offspring of a study participant, results in abnormal pregnancy outcomes or any other situation based on appropriate medical or scientific judgement.

Stage 2: Number of Participants 24 to 59 Months of Age in Africa With Deviations From Normal Values of Haematological, Renal, and Hepatic Panel Test Results After First Study Intervention
At Day 8

Panel tests include measures of ALT, AST, creatinine, basophils, eosinophils, erythrocytes, haematocrit, haemoglobin, lymphocytes, monocytes, neutrophils, platelets and WBC. Categories reported when comparing Day 1 (baseline) and normal range hematological, renal and hepatic laboratory results are defined as follows: \<parameter\>,\<range at baseline\>,\<range at timing\>, where range is being classified as Below = value below; Within = value within; and Above = value above the laboratory reference range defined for the specified visit and laboratory parameter.

Stage 2: Number of Participants 24 to 59 Months of Age in Africa With Deviations From Normal Values of Haematological, Renal, and Hepatic Panel Test Results After Second Study Intervention
At Day 92

Panel tests include measures of ALT, AST, creatinine, basophils, eosinophils, erythrocytes, haematocrit, haemoglobin, lymphocytes, monocytes, neutrophils, platelets and WBC. Categories reported when comparing Day 85 (baseline) and normal range hematological, renal and hepatic laboratory results are defined as follows: \<parameter\>,\<range at baseline\>,\<range at timing\>, where range is being classified as Below = value below; Within = value within; and Above = value above the laboratory reference range defined for the specified visit and laboratory parameter.

Stage 2: Number of Participants 9 Months of Age in Africa With Solicited Administration Site Events - Infants Safety Cohort
Within 7 days after each study intervention (administered at Day 1, Day 85 and Day 253)

The solicited administration site events assessed were erythema, pain, and swelling.

Stage 2: Number of Participants 9 Months of Age in Africa With Solicited Administration Site Events - Infants Dose-finding Cohort
Within 7 days after each study intervention (administered at Day 1, Day 85 and Day 253)

The solicited administration site events assessed were erythema, pain, and swelling.

Stage 2: Number of Participants 9 Months of Age in Africa With Solicited Systemic Events - Infants Safety Cohort
Within 7 days after each study intervention (administered at Day 1, Day 85 and Day 253)

The solicited systemic event is fever. Fever is defined as temperature equal to or above (=\>) 38.0°C.

Stage 2: Number of Participants 9 Months of Age in Africa With Solicited Systemic Events - Infants Dose-finding Cohort
Within 7 days after each study intervention (administered at Day 1, Day 85 and Day 253)

The solicited systemic event is fever. Fever is defined as temperature equal to or above (=\>) 38.0°C.

Stage 2: Number of Participants 9 Months of Age in Africa With Unsolicited Adverse Events (AEs) - Infants Safety Cohort
Within 28 days after each study intervention (administered at Day 1, Day 85 and Day 253)

An unsolicited AE is defined as an AE reported in addition to those solicited during the clinical study. Also, any 'solicited' symptom with onset outside the specified period of follow-up for solicited symptoms is reported as an unsolicited adverse event.

Stage 2: Number of Participants 9 Months of Age in Africa With Unsolicited Adverse Events (AEs) - Infants Dose-finding Cohort
Within 28 days after each study intervention (administered at Day 1, Day 85 and Day 253)

An unsolicited AE is defined as an AE reported in addition to those solicited during the clinical study. Also, any 'solicited' symptom with onset outside the specified period of follow-up for solicited symptoms is reported as an unsolicited adverse event.

Stage 2: Number of Participants 9 Months of Age in Africa With Serious Adverse Events (SAEs) - Infants Safety Cohort
From Day 1 to Day 281

An SAE is defined as any untoward medical occurrence that results in death, is life-threatening, requires inpatient hospitalization or prolongation of existing hospitalization, results in disability/incapacity, is a congenital anomaly/birth defect in the offspring of a study participant, results in abnormal pregnancy outcomes or any other situation based on appropriate medical or scientific judgement.

Stage 2: Number of Participants 9 Months of Age in Africa With Serious Adverse Events (SAEs) - Infants Dose-finding Cohort
From Day 1 to Day 281

An SAE is defined as any untoward medical occurrence that results in death, is life-threatening, requires inpatient hospitalization or prolongation of existing hospitalization, results in disability/incapacity, is a congenital anomaly/birth defect in the offspring of a study participant, results in abnormal pregnancy outcomes or any other situation based on appropriate medical or scientific judgement.

Stage 2: Number of Participants 9 Months of Age in Africa With Deviations From Normal Values of Haematological, Renal, and Hepatic Panel Test Results After First Study Intervention - Infants Safety Cohort
At Day 8

Panel tests include measures of alanine aminotransferase (ALT), aspartate aminotransferase (AST), creatinine, potassium, sodium, urea, basophils, eosinophils, erythrocytes, haematocrit, haemoglobin, lymphocytes, monocytes, neutrophils, platelets and white blood cells (WBC). Categories reported when comparing Day 1 (baseline) and normal range hematological, renal and hepatic laboratory results are defined as follows: \<parameter\>,\<range at baseline\>,\<range at timing\>, where range is being classified as Below = value below; Within = value within; and Above = value above the laboratory reference range defined for the specified visit and laboratory parameter.

Stage 2: Number of Participants 9 Months of Age in Africa With Deviations From Normal Values of Haematological, Renal, and Hepatic Panel Test Results After First Study Intervention - Infants Dose-finding Cohort
At Day 8

Panel tests include measures of ALT, AST, creatinine, basophils, eosinophils, erythrocytes, haematocrit, haemoglobin, lymphocytes, monocytes, neutrophils, platelets and WBC. Categories reported when comparing Day 1 (baseline) and normal range hematological, renal and hepatic laboratory results are defined as follows: \<parameter\>,\<range at baseline\>,\<range at timing\>, where range is being classified as Below = value below; Within = value within; and Above = value above the laboratory reference range defined for the specified visit and laboratory parameter.

Stage 2: Number of Participants 9 Months of Age in Africa With Deviations From Normal Values of Haematological, Renal, and Hepatic Panel Test Results After Second Study Intervention - Infants Safety Cohort
At Day 92

Panel tests include measures of ALT, AST, creatinine, potassium, sodium, urea, basophils, eosinophils, erythrocytes, haematocrit, haemoglobin, lymphocytes, monocytes, neutrophils, platelets and WBC. Categories reported when comparing Day 1 (baseline) and normal range hematological, renal and hepatic laboratory results are defined as follows: \<parameter\>,\<range at baseline\>,\<range at timing\>, where range is being classified as Below = value below; Within = value within; and Above = value above the laboratory reference range defined for the specified visit and laboratory parameter.

Stage 2: Number of Participants 9 Months of Age in Africa With Deviations From Normal Values of Haematological, Renal, and Hepatic Panel Test Results After Second Study Intervention - Infants Dose-finding Cohort
At Day 92

Panel tests include measures of alanine aminotransferase (ALT), aspartate aminotransferase (AST), creatinine, potassium, sodium, urea, basophils, eosinophils, erythrocytes, haematocrit, haemoglobin, lymphocytes, monocytes, neutrophils, platelets and white blood cells (WBC). Categories reported when comparing Day 1 (baseline) and normal range hematological, renal and hepatic laboratory results are defined as follows: \<parameter\>,\<range at baseline\>,\<range at timing\>, where range is being classified as Below = value below; Within = value within; and Above = value above the laboratory reference range defined for the specified visit and laboratory parameter.

Stage 2: Number of Participants 9 Months of Age in Africa With Deviations From Normal Values of Haematological, Renal, and Hepatic Panel Test Results After Third Study Intervention - Infants Safety Cohort
At Day 260

Panel tests include measures of ALT, AST, creatinine, basophils, eosinophils, erythrocytes, haematocrit, haemoglobin, lymphocytes, monocytes, neutrophils, platelets and WBC. Categories reported when comparing Day 1 (baseline) and normal range hematological, renal and hepatic laboratory results are defined as follows: \<parameter\>,\<range at baseline\>,\<range at timing\>, where range is being classified as Below = value below; Within = value within; and Above = value above the laboratory reference range defined for the specified visit and laboratory parameter.

Stage 2: Number of Participants 9 Months of Age in Africa With Deviations From Normal Values of Haematological, Renal, and Hepatic Panel Test Results After Third Study Intervention - Infants Dose-finding Cohort
At Day 260

Panel tests include measures of alanine aminotransferase (ALT), aspartate aminotransferase (AST), creatinine, potassium, sodium, urea, basophils, eosinophils, erythrocytes, haematocrit, haemoglobin, lymphocytes, monocytes, neutrophils, platelets and white blood cells (WBC). Categories reported when comparing Day 1 (baseline) and normal range hematological, renal and hepatic laboratory results are defined as follows: \<parameter\>,\<range at baseline\>,\<range at timing\>, where range is being classified as Below = value below; Within = value within; and Above = value above the laboratory reference range defined for the specified visit and laboratory parameter.

Secondary Endpoints

Number of infants with solicited administration-site events
During 7 days after each study intervention administration (study interventions administered at Day 1 and Day 169)
Number of infants with solicited systemic events
During 7 days after each study intervention administration (study interventions administered at Day 1 and Day 169)
Number of infants with unsolicited adverse events (AEs)
During 28 days after each study intervention administration (study interventions administered at Day 1 and Day 169)
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Study Design & Arms

AllocationRANDOMIZED
MaskingNONE
ModelPARALLEL
PurposePREVENTION

Treatment Arms

ArmTypeDescription
H06_01TP Study_Infants_Selected doseEXPERIMENTALInfants who received 3 doses of the altSonflex1-2-3 vaccine on Day 1, Day 85, and Day 253 in the H06\_01TP parent study.
H06_01TP Study_ ST2_Infants_ControlACTIVE_COMPARATORInfants who received 2 doses of the Menveo vaccine on Day 1 and Day 85, and 1 dose of the Infanrix hexa vaccine on Day 281 in the H06\_01TP parent study.
H06_02TP Study_Infants_Selected doseEXPERIMENTALInfants who received 2 doses of the altSonflex1-2-3 vaccine on Day 1 and Day 169 in the H06\_02TP parent study.
H06_02TP Study_ Infants_ControlACTIVE_COMPARATORInfants who received 1 dose of the TYPHIBEV vaccine on Day 1 and 1 dose of the Infanrix hexa vaccine on Day 169 in the H06\_02TP parent study.
altSonflex1-2-3 Dose_A GroupEXPERIMENTALParticipants randomized to receive altSonflex1-2-3 Dose A and MR-VAC on Day 1 and Day 169.
altSonflex1-2-3 Dose_B GroupEXPERIMENTALParticipants randomized to receive altSonflex1-2-3 Dose B and MR-VAC on Day 1 and Day 169.
altSonflex1-2-3 Dose_C GroupEXPERIMENTALParticipants randomized to receive altSonflex1-2-3 Dose C and MR-VAC on Day 1 and Day 169.
Control GroupACTIVE_COMPARATORParticipants randomized to receive TYPHIBEV on Day 1, Infanrix hexa on Day 169 and MR-VAC on Day 1 and Day 169.
Stage 1 Adults: altSonflex1-2-3 High Dose Group 1EXPERIMENTALEuropean participants 18-50 years of age were randomized to receive a high dose of altSonflex1-2-3 on Day 1 and Day 85. High dose of altSonflex1-2-3 contained 15 micrograms (µg) of O-antigen (OAg) each Shigella serotype (S. sonnei, S. flexneri 1b, S. flexneri 2a, S. flexneri 3a).
Stage 1 Adults: altSonflex1-2-3 High Dose Group 2EXPERIMENTALEuropean participants 18-50 years of age were randomized to receive a high dose of altSonflex1-2-3 on Day 1 and Day 169. High dose of altSonflex1-2-3 contained 15 µg OAg of each Shigella serotype (S. sonnei, S. flexneri 1b, S. flexneri 2a, S. flexneri 3a).
Stage 1 Adults: Placebo GroupPLACEBO_COMPARATOREuropean participants 18-50 years of age were randomized to receive 1 dose of Placebo on Day 1 and on Day 85 or 169. All participants in Step 1 that received placebo were pooled, as pre-specified in Statistical Analysis Plan.
Stage 2 Adults: altSonflex1-2-3 High DoseEXPERIMENTALAfrican participants 18-50 years of age were randomized to receive a high dose of altSonflex1-2-3 on Day 1 and Day 85. High dose of altSonflex1-2-3 contained of 15 µg OAg of each Shigella serotype (S. sonnei, S. flexneri 1b, S. flexneri 2a, S. flexneri 3a).
Stage 2 Adults: ControlACTIVE_COMPARATORAfrican participants 18-50 years of age were randomized to receive 1 dose of MENVEO as comparator on Day 1 and 1 dose of BOOSTRIX as comparator Day 85.
Stage 2 Children: altSonflex1-2-3 Medium DoseEXPERIMENTALAfrican participants 24-59 months of age were randomized to receive a medium dose of altSonflex1-2-3 on Day 1 and Day 85. Medium dose of altSonflex1-2-3 contained 7.5 µg OAg of each Shigella serotype (S. sonnei, S. flexneri 1b, S. flexneri 2a, S. flexneri 3a).
Stage 2 Children: altSonflex1-2-3 High DoseEXPERIMENTALAfrican participants 24-59 months of age were randomized to receive a high dose of altSonflex1-2-3 on Day 1 and Day 85. High dose of altSonflex1-2-3 contained 15 µg OAg of each Shigella serotype (S. sonnei, S. flexneri 1b, S. flexneri 2a, S. flexneri 3a).
Stage 2 Children: ControlACTIVE_COMPARATORAfrican participants 24-59 months of age were randomized to receive 1 dose of MENVEO as comparator on Day 1 and 1 dose of TYPHIM VI as comparator on Day 85.
Stage 2 Infants safety cohort: altSonflex1-2-3 Low DoseEXPERIMENTALAfrican participants 9 months of age were randomized to receive a low dose of altSonflex1-2-3 on Day 1, Day 85 and Day 253. The measles-rubella vaccine (MR-VAC) was administered on Day 29 and Day 281. Low dose of altSonflex1-2-3 contained 3.75 µg OAg of each Shigella serotype (S. sonnei, S. flexneri 1b, S. flexneri 2a, S. flexneri 3a).
Stage 2 Infants safety cohort: altSonflex1-2-3 Medium DoseEXPERIMENTALAfrican participants 9 months of age were randomized to receive a medium dose of altSonflex1-2-3 on Day 1, Day 85 and Day 253. MR-VAC was administered on Day 29 and Day 281. Medium dose of altSonflex1-2-3 contained 7.5 µg OAg of each Shigella serotype (S. sonnei, S. flexneri 1b, S. flexneri 2a, S. flexneri 3a).
Stage 2 Infants safety cohort: altSonflex1-2-3 High DoseEXPERIMENTALAfrican participants 9 months of age were randomized to receive a high dose of altSonflex1-2-3 on Day 1, Day 85 and Day 253. MR-VAC was administered on Day 29 and Day 281. High dose of altSonflex1-2-3 contained 15 µg OAg of each Shigella serotype (S. sonnei, S. flexneri 1b, S. flexneri 2a, S. flexneri 3a).
Stage 2 Infants safety cohort: ControlACTIVE_COMPARATORAfrican participants 9 months of age were randomized to receive a dose of MENVEO as comparator on Day 1 and Day 85 and INFRANRIX HEXA as comparator on Day 253. MR-VAC was administered on Day 29 and Day 281.
Stage 2 Infants dose-finding cohort: altSonflex1-2-3 Low DoseEXPERIMENTALAfrican participants 9 months of age were randomized to receive a low dose of altSonflex1-2-3 on Day 1, Day 85 and Day 253. MR-VAC was co-administered on Day 1 and Day 253. This cohort was created to identify the preferred dose among low, medium and high doses. Low dose of altSonflex1-2-3 contained 3.75 µg OAg of each Shigella serotype (S. sonnei, S. flexneri 1b, S. flexneri 2a, S. flexneri 3a).
Stage 2 Infants dose-finding cohort: altSonflex1-2-3 Medium DoseEXPERIMENTALAfrican participants 9 months of age were randomized to receive a medium dose of altSonflex1-2-3 on Day 1, Day 85 and Day 253. MR-VAC was co-administered on Day 1 and Day 253. This cohort was created to identify the preferred dose among low, medium and high doses. Medium dose of altSonflex1-2-3 contained 7.5 µg OAg of each Shigella serotype (S. sonnei, S. flexneri 1b, S. flexneri 2a, S. flexneri 3a).
Stage 2 Infants dose-finding cohort: altSonflex1-2-3 High DoseEXPERIMENTALAfrican participants 9 months of age were randomized to receive a high dose of altSonflex1-2-3 on Day 1, Day 85 and Day 253. MR-VAC was co-administered on Day 1 and Day 253. This cohort was created to identify the preferred dose among low, medium and high doses. High dose of altSonflex1-2-3 contained 15 µg OAg of each Shigella serotype (S. sonnei, S. flexneri 1b, S. flexneri 2a, S. flexneri 3a).
Stage 2 Infants dose-finding cohort: ControlACTIVE_COMPARATORAfrican participants 9 months of age were randomized to receive a dose of MENVEO as comparator on Day 1 and Day 85 and INFRANRIX HEXA as comparator on Day 253. MR-VAC was co-administered on Day 1 and Day 253. This cohort was created to identify the preferred dose among low, medium and high doses.

Interventions

NameTypeDescription
AltSonflex1-2-3BIOLOGICALNo intervention is administered in this extension study. The selected dose of altSonflex1-2-3 vaccine was administered intramuscularly in the participants' thigh during the H06\_01TP (212149) parent study on Day 1, Day 85, and Day 253; or on Day 1 and Day 169 during the H06\_02TP (219449) study.
MenveoBIOLOGICALNo intervention is administered in this extension study. The Menveo vaccine was administered intramuscularly in the participants' thigh on Day 1 and Day 85 during the H06\_01TP (212149) parent study.
Infanrix hexaBIOLOGICALNo intervention is administered in this extension study. The Infanrix hexa vaccine was administered intramuscularly in the participants' thigh on Day 281 during the H06\_01TP (212149) study; or on Day 169 during the H06\_02TP (219449) parent study.
TYPHIBEVBIOLOGICALNo intervention is administered in this extension study. The TYPHIBEV vaccine was administered intramuscularly in the participants' thigh on Day 1 during the H06\_02TP (219449) parent study.
altSonflex1-2-3 Dose ABIOLOGICALaltSonflex1-2-3 Dose A administered intramuscularly on Day 1 and Day 169
altSonflex1-2-3 Dose BBIOLOGICALaltSonflex1-2-3 Dose B administered intramuscularly on Day 1 and Day 169
altSonflex1-2-3 Dose CBIOLOGICALaltSonflex1-2-3 Dose C administered intramuscularly on Day 1 and Day 169
MR-VACBIOLOGICALMR-VAC co-administered subcutaneously on Day 1 and Day 169
AltSonflex1-2-3 High DoseBIOLOGICAL2 doses in adults 18-50 years of age and children 24-59 months of age, 3 doses in infants 9 months of age
AltSonflex1-2-3 Medium DoseBIOLOGICAL2 doses in children 24-59 months of age, 3 doses in infants 9 months of age
AltSonflex1-2-3 Low DoseBIOLOGICAL3 doses in infants 9 months of age
BoostrixCOMBINATION_PRODUCT1 dose in adults 18-50 years of age (stage 2)
Typhim-ViCOMBINATION_PRODUCT1 dose in children 24-59 months of age
altSonflex PlaceboDRUG2 doses in adults 18-50 years of age (stage 1)
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Eligibility Criteria

Age Range26 Months to 55 Months
SexALL
Healthy VolunteersYes

Inclusion Criteria: * Children who, as infants, previously participated in two completed studies (H06\_01TP or H06\_02TP) and were vaccinated with 3 or 2 doses of altSonflex1-2-3 or control vaccines, respectively, completed all previous vaccinations and are 12±1 months after the last altSonflex1-2-...

Countries:KenyaBelgium
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Recent Changes (Last 90 Days)

MEDIUMJul 23, 2026NCT05073003TRIAL_REMOVED: changed
MEDIUMJul 23, 2026NCT05073003TRIAL_REMOVED: changed
MEDIUMJul 23, 2026NCT05073003TRIAL_REMOVED: changed

Frequently asked questions about AltSonflex1-2-3 High Dose

What is AltSonflex1-2-3 High Dose?

AltSonflex1-2-3 High Dose is an investigational monoclonal antibody developed by GSK plc for diarrhoea in the gastrointestinal therapeutic area. It is a multicomponent Shigella vaccine candidate being studied for the prevention of shigellosis, a form of diarrhoeal disease. It is currently in Phase 2 clinical development.

What is AltSonflex1-2-3 High Dose used for?

AltSonflex1-2-3 High Dose is being developed to prevent shigellosis, a diarrhoeal disease caused by Shigella bacteria. Clinical trials have enrolled adults, children, and infants, including African children, with diarrhoea listed as the condition under study. The vaccine is intended to reduce the burden of Shigella-related diarrhoeal illness.

Who makes AltSonflex1-2-3 High Dose?

AltSonflex1-2-3 High Dose is developed by GSK plc, which trades under the ticker GSK. The vaccine candidate originates from GVGH, GSK's global health vaccines unit, as reflected in the Phase 1 trial title referencing the GVGH altSonflex1-2-3 vaccine against shigellosis.

What phase is AltSonflex1-2-3 High Dose in?

AltSonflex1-2-3 High Dose is in Phase 2 clinical development. Three trials have been conducted in total: one Phase 1 study and two Phase 2 studies. Two trials are completed, and one Phase 2 trial is not yet recruiting. The candidate is investigational and has not been approved.

What clinical trials is AltSonflex1-2-3 High Dose in?

AltSonflex1-2-3 High Dose has been studied in three trials. NCT05073003 was a completed Phase 1 study in Belgium and Kenya. NCT06663436 was a completed Phase 2 study in Kenya. NCT07320716 is a Phase 2 long-term immunogenicity study in African children that is not yet recruiting.

Is AltSonflex1-2-3 High Dose the same as altSonflex1-2-3 Dose A?

Yes. AltSonflex1-2-3 High Dose is also known as altSonflex1-2-3 Dose A, and is often shortened to AltSonflex1-2-3. These names refer to the same GSK Shigella vaccine candidate in Phase 2 development for diarrhoea, so searches under any of these names point to the same asset.