Recent Updates
Recently added Catalysts

VXB-241

Phase 1

Healthy Volunteers | Monoclonal antibody | Other |Sanofi|Last Updated: May 20, 2026

Success Probability
Approval Probability 71%
TA Base Rate26%
Adjusted LOA41%
ML RiskLOW_RISK
Premium
Market & Valuation
rNPV $3.2B
Market Size $9.4B
Revenue Basis $1.6B
Competitors 6
Premium
Trial Design
RandomizedDouble-BlindPLACEBO_CONTROLLEDDMCBiomarker
Total Trials1
Total Enrollment144
FDA Designations
No designations recorded
Clinical Trials (1)
NCT IDTitlePhaseStatusEnrollmentVelocityDesignStartCompletionLast UpdatedSitesCountries
NCT06556147A Study of RSV-HMPV Bivalent Vaccine VXB-241 in Older AdultsPHASE1 ACTIVE NOT_RECRUITING 144 — — Aug 13, 2024May 1, 2027May 20, 20264 Australia
Unlock Drug Trial Details
Study Endpoints
Primary Endpoints
Proportion of Older Adult Participants With 1 or More Unsolicited AEs
1 month after first IMP injection (Days 1 to 30)
Proportion of Older Adult Participants With 1 or More Solicited AEs
7 days after first IMP injection (Days 1 to 8)
Geometric Mean Fold Increase (GMFI) of RSV-A, RSV-B, hMPV-A, and hMPV-B Serum Neutralizing Antibody Titers in Older Adults
Pre-injection baseline to 1 month (Day 30) after first IMP injection

GMFI is defined as geometric mean of ratios of specific antibody titer/concentration at each post-vaccination time point over pre-vaccination baseline.

Ratio of Dose-response Curves for GMFIs of RSV-A, RSV-B, hMPV-A and hMPV-B Serum Neutralizing Antibody Titers in Older Adults
Pre-injection baseline to 1 month (Day 30) after first IMP injection

Ratio of VXB-241 dose versus GMFI of RSV-A, RSV-B, hMPV-A and hMPV-B will be calculated.

Secondary Endpoints
Proportion of Older Adult Participants With 1 or More Unsolicited AEs and With 1 or More Severe Unsolicited AE
1 month after first IMP injection (Days 1 to 30) and 1 month after second IMP injection (revaccination, Days 364 to 394)
Proportion of Older Adult Participants With Serious Adverse Events (SAEs), AEs of Special Interest (AESIs), and Premature Discontinuation Associated AEs (PDAEs)
1 month after first IMP injection (Days 1 to 30) and 1 month after second IMP injection (revaccination, Days 364 to394), and throughout follow-up (Days 1 to 720)
Mean Change From Baseline for Abnormal and Severe Abnormal Hematology Laboratory Values for Hemoglobin in Older Adults
7 days (Day 8) and 1 month (Day 30) after first IMP injection, and 1 month (Day 394) after second IMP injection (revaccination
Unlock Study Endpoints
Study Design & Arms
AllocationRANDOMIZED
MaskingDOUBLE
ModelSEQUENTIAL
PurposePREVENTION
Treatment Arms
ArmTypeDescription
Stage 1, Day 1, Sequential Cohort 1EXPERIMENTALYounger and older adult participants will receive VXB-241 60 mcg (low dose) or Placebo, intramuscularly (IM), once on Day 1.
Stage 1, Day 1, Sequential Cohort 2EXPERIMENTALYounger and older adult participants will receive VXB-241 120 mcg (medium dose) or Placebo, IM, once on Day 1.
Stage 1, Day 1, Sequential Cohort 3EXPERIMENTALYounger and older adult participants will receive VXB-241 240 mcg (medium-high dose) or Placebo, IM, once on Day 1.
Stage 1, Day 1, Sequential Cohort 4EXPERIMENTALYounger and older adult participants will receive VXB-241 480 mcg (high dose) or Placebo, IM, once on Day 1.
Stage 2, Day 1, Concurrent Group 1aEXPERIMENTALOlder adult participants will receive VXB-241 60 mcg (low dose), IM, once on Day 1.
Stage 2, Day 1, Concurrent Group 1bEXPERIMENTALOlder adult participants will receive VXB-241 120 mcg (medium dose), IM, once on Day 1.
Stage 2, Day 1, Concurrent Group 1cEXPERIMENTALOlder adult participants will receive VXB-241 240 mcg (medium-high dose), IM, once on Day 1.
Stage 2, Day 1, Concurrent Group 1dEXPERIMENTALOlder adult participants will receive VXB-241 480 mcg (high dose), IM, once on Day 1.
Stage 2, Day 1, Concurrent Group 2aACTIVE_COMPARATOROlder adult participants will receive Arexvy 120 mcg, IM, once on Day 1.
Stage 2, Day 1, Concurrent Group 3aPLACEBO_COMPARATOROlder adult participants will receive Placebo, IM, once on Day 1.
Group 1e: VXB-241 Revaccination in VXB-241 RecipientsEXPERIMENTALApproximately 50% of the older adult participants who received VXB-241 240 mcg, will receive VXB-241 240 mcg, IM, (based on 1 month post 1st IMP injection results), once on Day 364 in the second year of the study.
Group 1f: Placebo Revaccination in VXB-241 RecipientsPLACEBO_COMPARATORApproximately 50% of the older adult participants who received VXB-241 (any dose level), will receive Placebo, IM, once on Day 364 in the second year of the study.
Group 2b: Placebo Arexvy RevaccinationPLACEBO_COMPARATORAll older adult participants who received Arexvy 120 mcg will receive Placebo revaccination, IM, once on Day 364 in the second year of the study.
Group 3b: VXB-241EXPERIMENTALAll older adult participants who received Placebo will receive VXB-241 240 mcg (based on 1 month post 1st IMP injection results), IM, once on Day 364 in the second year of the study.
Interventions
NameTypeDescription
VXB-241 60 mcg (Low Dose)BIOLOGICALVXB-241 low dose, single, IM injection.
VXB-241 120 mcg (Medium Dose)BIOLOGICALVXB-241 medium dose, single, IM injection.
VXB-241 240 mcg (Medium-high Dose)BIOLOGICALVXB-241 medium-high dose, single, IM injection.
VXB-241 480 mcg (High Dose)BIOLOGICALVXB-241 high dose, single, IM injection.
VXB-241 240 mcgBIOLOGICALVXB-241 240 mcg (RSV preF 120 mcg + hMPV preF 120 mcg) (based on 1 month post 1st IMP injection results) single, IM injection.
PlaceboOTHERPlacebo, single, IM injection.
Arexvy 120 mcgBIOLOGICALArexvy 120 mcg, single, IM injection.
Unlock Study Design Details
Eligibility Criteria
Age Range18 Years — 83 Years
SexALL
Healthy VolunteersYes
Study Sites4

Inclusion Criteria: 1. Male or female, 18 to 40 years of age (yoa) (younger adult) or 60 to 83 yoa (older adult). 2. Evidence of signed and dated participant informed consent form (PICF) prior to any study procedure, indicating that the participant has been informed of all pertinent aspects of the ...

Countries:Australia
Unlock Eligibility Criteria
Recent Changes (Last 90 Days)
LOWMay 24, 2026NCT06556147studyFirstPostDate: changed