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High-Dose Quadrivalent Influenza Vaccine

Phase 3

Influenza (Healthy Volunteers) | Monoclonal antibody | Infectious Disease |Sanofi|Last Updated: Sep 24, 2025

Success Probability
Approval Probability 71%
TA Base Rate26%
Adjusted LOA41%
ML RiskLOW_RISK
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Market & Valuation
rNPV $3.2B
Market Size $9.4B
Revenue Basis $1.6B
Competitors 6
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Trial Design
RandomizedDouble-BlindACTIVE_CONTROLLED
Total Trials1
Total Enrollment165
FDA Designations
No designations recorded
Clinical Trials (1)
NCT IDTitlePhaseStatusEnrollmentVelocityDesignStartCompletionLast UpdatedSitesCountries
NCT04537234Study to Assess the Immune Response and the Safety Profile of a High-Dose Quadrivalent Influenza Vaccine (QIV-HD) Compared to a Standard-Dose Quadrivalent Influenza Vaccine (QIV-SD) in Taiwanese Adults 65 Years of Age and OlderPHASE3 COMPLETED 165Nov 10, 2020Feb 9, 2021Sep 24, 20254 Taiwan
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Study Endpoints
Primary Endpoints
Geometric Mean Titers (GMTs) of Influenza Vaccine Antibodies at Day 0
Day 0 (pre-vaccination)

GMTs of anti-influenza antibodies were measured using hemagglutination inhibition (HAI) assay for 4 influenza virus strains: A/H1N1, A/H3N2, B1 (B Victoria Lineage), and B2 (B Yamagata Lineage). Titers were expressed in terms of 1/dilution.

Geometric Mean Titers of Influenza Vaccine Antibodies at Day 28
Day 28 (post-vaccination)

GMTs of anti-influenza antibodies were measured using HAI assay for 4 influenza virus strains: A/H1N1, A/H3N2, B1 (B Victoria lineage), and B2 (B Yamagata lineage). Titers were expressed in terms of 1/dilution.

Geometric Mean Titers Ratio (GMTR) of Influenza Vaccine Antibodies
Day 0 (pre-vaccination), Day 28 (post-vaccination)

GMTRs of anti-influenza antibodies were measured by using HAI assay for 4 influenza virus strains: A/H1N1, A/H3N2, B1 (B Victoria lineage), and B2 (B Yamagata lineage). GMTRs were calculated as the ratio of GMTs post-vaccination (on Day 28) and pre-vaccination (on Day 0).

Percentage of Participants Achieving Seroconversion Against Influenza Virus Antigens
Day 28 (post-vaccination)

Anti-influenza antibodies were measured by HAI assay for 4 influenza virus strains: A/H1N1, A/H3N2, B1 (B Victoria lineage), and B2 (B Yamagata lineage). Seroconversion was defined as either a pre-vaccination HAI titer less than (\<) 10 (1/dilution) at Day 0 and a post-vaccination titer greater than or equal to (\>=) 40 (1/dilution) at Day 28 or a pre-vaccination titer \>=10 (1/dilution) at Day 0 and a \>= four-fold increase in post-vaccination titer at Day 28.

Percentage of Participants With Antibody Titers >=40 (1/Dilution) at Day 0
Day 0 (pre-vaccination)

Antibody titer was measured by using HAI assay method for 4 influenza virus strains: A/H1N1, A/H3N2, B1 (B Victoria lineage), and B2 (B Yamagata lineage).

Percentage of Participants With Antibody Titers >=40 (1/Dilution) at Day 28
Day 28 (post-vaccination)

Antibody titer was measured using HAI assay method for 4 influenza virus strains: A/H1N1, A/H3N2, B1 (B Victoria lineage), and B2 (B Yamagata lineage).

Number of Participants With Immediate Unsolicited Systemic Adverse Events (AEs)
Within 30 minutes post-vaccination

An AE was any untoward medical occurrence in a patient or in a clinical investigation participant administered a medicinal product and which did not had any causal relationship with the treatment. An unsolicited AE was an observed AE that did not fulfill the conditions prelisted in the case report book (CRB) in terms of diagnosis and/or onset window post-vaccination. All participants were observed for 30 minutes after vaccination, and any unsolicited systemic AEs occurred during that time were recorded as immediate unsolicited AEs in the CRB.

Number of Participants With Solicited Injection Site and Systemic Reactions
Within 7 days post-vaccination

A solicited reaction was an "expected" adverse reaction (sign or symptom) observed and reported under the conditions (nature and onset) prelisted (i.e., solicited) in the protocol and CRB and considered as related to the product administered. Solicited injection site reactions included pain, erythema, swelling, induration, and bruising. Solicited systemic reactions included fever, headache, malaise, myalgia and shivering.

Number of Participants With Unsolicited Adverse Events
Within 28 days post-vaccination

An AE was any untoward medical occurrence in a patient or in a clinical investigation participant administered a medicinal product and which did not had any causal relationship with the treatment. An unsolicited AE was an observed AE that did not fulfill the conditions prelisted in the CRB in terms of diagnosis and/or onset window post-vaccination.

Number of Participants With Serious Adverse Events (SAEs) Including Adverse Event of Special Interest (AESIs)
From Day 0 up to 28 days post-vaccination

An SAE was any untoward medical occurrence that at any dose resulted in death, was life-threatening, required inpatient hospitalization or prolongation of existing hospitalization, resulted in persistent or significant disability/incapacity, was a congenital anomaly/birth defect, or was an important medical event. AESIs was defined as event for which ongoing monitoring and rapid communication by the investigator to the sponsor was done.

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Study Design & Arms
AllocationRANDOMIZED
MaskingQUADRUPLE
ModelPARALLEL
PurposePREVENTION
Treatment Arms
ArmTypeDescription
Group 1: High-Dose Quadrivalent Influenza Vaccine (QIV-HD)EXPERIMENTALParticipants received a single injection of 0.7 milliliters (mL) QIV-HD, intramuscularly (IM) at Day 0.
Group 2: Standard-Dose Quadrivalent Influenza Vaccine (QIV-SD)ACTIVE_COMPARATORParticipants received a single injection of 0.5 mL QIV-SD, IM at Day 0.
Interventions
NameTypeDescription
High-Dose Quadrivalent Influenza VaccineBIOLOGICALPharmaceutical form: Suspension for injection in pre-filled syringe, Route of administration: IM
Standard-Dose Quadrivalent Influenza VaccineBIOLOGICALPharmaceutical form: Suspension for injection in pre-filled syringe, Route of administration: IM
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Eligibility Criteria
Age Range65 Years — N/A
SexALL
Healthy VolunteersYes
Study Sites4

Inclusion criteria : * 65 years and older on the day of inclusion. * Able to attend all scheduled visits and complied with all study procedures. Exclusion criteria: * Participation at the time of study enrollment (or in the 4 weeks preceding the study vaccination) or planned participation during ...

Countries:Taiwan
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