Efficacy, Immunogenicity, and Safety of OVX836 Influenza Vaccine in Preventing RT-PCR-Confirmed Influenza Type A in Healthy Adults Aged 18-59: A Phase 2b Study
- Trial ID
- 2024-520354-37-00
- Protocol
- OVX836-005
- Sponsor
- Osivax
Trial statistics
Diseases & Conditions
Objectives
The primary objective of this study is to evaluate the **efficacy** of the OVX836 influenza vaccine (480 μg) in preventing RT-PCR-confirmed influenza Type A clinical disease, as defined by protocol-specific influenza-like illness (ILI), in comparison to placebo. This objective is clinically relevant as it aims to determine the vaccine's effectiveness in reducing the incidence of confirmed influenza Type A, which is a significant cause of morbidity and mortality during influenza seasons.
Secondary objectives include:
- Evaluating the efficacy of the OVX836 vaccine in preventing laboratory-confirmed influenza Type A clinical disease using alternative ILI definitions, and by subtypes such as H1N1 and H3N2, compared to placebo.
- Assessing the vaccine's efficacy in preventing laboratory-confirmed influenza clinical disease irrespective of influenza strain, and specifically for influenza Type B.
- Determining the vaccine's efficacy at the peak of influenza season, as defined by national epidemiological sources.
- Evaluating the severity and duration of clinical influenza disease, and the impact on health-related quality of life (HRQoL) with the OVX836 vaccine compared to placebo.
- Combining and evaluating a composite endpoint that considers the severity and duration of clinical influenza disease and its impact on HRQoL.
- Assessing the vaccine's efficacy in preventing clinical influenza-like disease irrespective of the causal infectious agent.
- Evaluating the safety and reactogenicity of one dose of the OVX836 vaccine compared to placebo.
- Assessing the cell-mediated immune (CMI) and humoral responses to the vaccine in a subset of subjects.
Participants
The clinical trial focuses on evaluating the efficacy of the OVX836 influenza vaccine in preventing **Influenza disease**. The study population comprises healthy male and female subjects aged between 18 and 59 years. Participants are required to be socially active, living in environments with frequent social interactions, such as families with children or settings with regular public contact. The trial includes individuals who are compliant with reproductive criteria and are capable of understanding and completing electronic diaries and patient-reported outcomes. Participants must be reliable and willing to adhere to study procedures throughout the trial duration. The sponsor has not provided information regarding the total number of participants involved in the study.
Plans and Procedures
The clinical trial is a **Phase 2b**, multicenter, randomized, double-blind, placebo-controlled study designed to evaluate the efficacy, immunogenicity, and safety of a single dose of the OVX836 influenza vaccine at a dosage of 480 µg. The trial targets healthy subjects aged 18 to 59 years and aims to prevent RT-PCR-confirmed **influenza Type A** clinical disease. The study is expected to commence recruitment on September 1, 2025, and conclude by May 17, 2026. Participants will be randomly assigned to receive either the OVX836 vaccine or a placebo, with both administered via intramuscular injection.
The trial will include several key visits: an initial screening visit, follow-up visits, and an end-of-study visit. During the screening visit, eligibility will be assessed based on criteria such as age, health status, and willingness to comply with study procedures. Follow-up visits will monitor the occurrence of influenza symptoms and any adverse events. The end-of-study visit will evaluate the overall health of participants and collect final data on the vaccine's efficacy and safety.
Participant involvement is expected to last approximately one year, with the primary endpoint being the first occurrence of RT-PCR-confirmed influenza Type A illness from 14 days post-vaccination. Secondary endpoints include the occurrence of laboratory-confirmed influenza illnesses and the assessment of health-related quality of life using standardized questionnaires. Conditions that may lead to early termination from the study include non-compliance with study procedures or the occurrence of serious adverse events. The trial will adhere to rigorous scientific standards to ensure the reliability and validity of the results.
Treatment
The clinical trial involves the administration of **OVX836**, an experimental influenza vaccine. OVX836 is a **solution for injection**, infusion, or inhalation, developed by OSIVAX S.A.S. The active substance in OVX836 is the **Influenza A (H1N1/WSN/1933) nucleoprotein fused to C-terminal fragments of two avian C4BP alfa chain sequences**. This structurally diverse substance is classified as a vaccine. The vaccine is administered intramuscularly at a dosage of 480 micrograms (µg) as a single dose. The maximum daily and total dose is 480 µg, with a treatment period of one day. Participant compliance with the dosing schedule is monitored throughout the study.
In addition to the experimental treatment, the study utilizes a placebo control, which is **CHLORURE DE SODIUM 0,9 % B. BRAUN**, a solution for infusion provided by B.BRAUN MEDICAL SAS. The active substance in this placebo is **sodium chloride**, a chemical compound. The placebo is administered via injection, with a maximum daily and total dose of 0.8 milliliters (ml), also over a one-day treatment period. The use of this placebo allows for a double-blind comparison to evaluate the efficacy and safety of the OVX836 vaccine in preventing RT-PCR-confirmed influenza Type A clinical disease in healthy subjects aged 18-59 years.
Efficacy
The efficacy of the OVX836 influenza vaccine will be assessed in a Phase 2b, multicenter, randomized, double-blind, placebo-controlled clinical trial. The primary endpoint for evaluating efficacy is the first occurrence of RT-PCR-confirmed influenza Type A illness, characterized by specific respiratory and systemic symptoms, occurring from 14 days after vaccination. Secondary endpoints include the first occurrence of laboratory-confirmed influenza Type A symptomatic illness, subtype of virus in confirmed cases, and the first occurrence of influenza symptomatic disease irrespective of strain or type. Additionally, the severity and duration of influenza-like illness (ILI) episodes will be measured using the Flu-PRO® questionnaire, and health-related quality of life (HRQoL) changes will be assessed using the SF-12 and EQ-5D-5L scores.
Data collection will involve the use of validated laboratory tests such as RT-PCR and culture confirmation for influenza diagnosis. The Flu-PRO® questionnaire will be employed to evaluate symptom severity and duration, while HRQoL will be assessed through the SF-12 and EQ-5D-5L instruments. Immunogenicity will be evaluated by measuring NP-specific T-cell responses and anti-NP IgG levels using IFNγ ELISPOT and ELISA, respectively, at baseline and Day 8 in a subset of participants. The analysis of efficacy endpoints will be conducted irrespective of the time between vaccination and case occurrence, ensuring a comprehensive evaluation of the vaccine's efficacy in preventing influenza Type A clinical disease.
Inclusion and Exclusion Criteria
Inclusion Criteria
- Written informed consent
- Healthy male or female subjects, as determined by medical history and medical examination.
- Between the ages of 18 and 59 years, inclusive
- Subjects compliant with the reproductive criteria for male and female participants
- Reliable and willing to make themselves available for the duration of the study, and willing and able to follow study procedures
- Able to read, understand, and complete an eDiary and electronic patient-reported outcome (ePRO)
- Subject socially active: living in a family with children or with other house-hold members, having frequent social contacts at university, work, in public places such as restaurants, theaters, public transportation, etc.
- Able to read and sign the subject information sheet and informed consent form (ICF).
Exclusion Criteria
- Previous vaccination with an authorized or experimental seasonal, zoonotic or pandemic influenza vaccine within 6 months before the day of vaccination or planned to receive it during the whole study period
- Prophylactic or therapeutic use of influenza antivirals within 7 days prior to the day of study vaccination or during the whole study duration.
- History of severe allergic reactions and/or anaphylaxis, or serious adverse reactions to vaccines or allergy to kanamycin or any other component of the OVX836 vaccine
- Females planning to become pregnant or planning to discontinue contraceptive precautions until the end of the trial
- Any contraindication to intramuscular administration, as judged by the Investigator
- Presence of extended tattoos on both deltoid muscles
- Individuals with a history of any illness that, in the opinion of the Investigator, might interfere with the results of the study, or pose additional risk to the subjects due to participation in the study, either directly or through any treatments administered for that illness
- Any known or suspected immunodeficient conditions
- Sponsor employees or Investigator site personnel directly affiliated with this study and their immediate families. Immediate family is defined as a spouse (or assimilated), parent, child, or sibling, whether biological or legally adopted
- Past or current history of significant autoimmune diseases, as judged by the Investigator
- Known or suspected infection with human immunodeficiency virus (HIV), hepatitis C virus (HCV), or hepatitis B virus (HBV).
- Any medical illness such as diabetes, hypertension, heart, renal, or hepatic diseases, as judged by the Investigator
- Planned absences without access to the investigational site, i.e. vacation or business trips, for more than 7 consecutive days during the study period
- Pregnant or lactating woman
- Having received another vaccine within 1 month prior to the day of study vaccination, except COVID-19 vaccines for which the minimum time period should be two weeks prior to study vaccination
- Planning to receive any other vaccines during the first 28 days following the study vaccine administration, except COVID-19 vaccines which can be administered from 14 days following the study vaccine administration
- Administration of any investigational or non-registered drug or vaccine within 1 month prior to the administration of study vaccines, or planned administration of any such product during the whole study period
- History of receiving blood, blood components, or immunoglobulins within 3 months prior to the day of vaccination, or planned to receive such product during the whole study period.
- Presence of an acute febrile illness on the day of planned vaccination (oral temperature ≥37.5°C; temporary exclusion criterion).
- Diagnosed long COVID-19 subjects
- Presence of a condition in the ear-nose-throat area, such as nasal septum deviation, atrophic rhinitis, etc…, that could render nasopharyngeal swabs more difficult to perform, or increase the risk of bleeding; to be confirmed by medical history question and inspection of nasal passage
- Behavioral or cognitive impairment, or psychiatric disease including suicidal ideation that, in the opinion of the Investigator, may interfere with the subject's ability to participate throughout the whole duration of the study
- Having participated or currently participating in an OVX836 study, except the current OVX836-005 study, or in the OVX-FLU-002 study
- Formal indication for influenza vaccination on an individual basis according to local recommendations, e.g. based on occupational risk (health care workers), or underlying medical conditions. An informed subject who would refuse to get the regular influenza vaccination would be allowed to participate in this study
- Past (stopped less than 6 months before enrolment) or current smoking habit above 10 cigarettes per day.
- Past (stopped less than 6 months before enrolment) or current history of heavy alcohol use, defined as follows: for men, consumption of more than 4 standard drinks on any day or more than 14 standard drinks per week, and for women, consumption of more than 3 standard drinks on any day or more than 7 standard drinks per week.
- Past (stopped less than 6 months before enrolment) or current use of recreational drugs, which could interfere with the adherence to the protocol procedures
- Chronic or prolonged treatment (>10 consecutive days) that can affect immune response, such as systemic (≥ 20 mg/day prednisone or equivalent or dexamethasone >4 mg/day), high dose inhaled corticosteroids (>800 μg/day beclomethasone or equivalent; occasional inhaled, topical or localized injections [intra-articular or intra-bursal] of corticosteroids for asthma therapy are allowed), or immunomodulators/suppressors (certain monoclonal antibodies can be approved on a case by case basis) within 28 days before study entry or during the whole study duration
- Chronic or prolonged (>10 days) use of systemic non-steroidal anti-inflammatory drugs, acetylsalicylic acid, or paracetamol within 7 days before study entry and up to 28 days post-vaccination
- Current or past history of progressive or severe uncontrolled neurological disorder, or current or past history of seizure disorder or Guillain-Barré syndrome
Trial Status by Country
| Country | Status | Start of Recruitment | Planned Patients |
|---|---|---|---|
 Belgium | Not Recruiting | 01 Sept 2025 | 1370 |
 Finland | Not Recruiting | 01 Sept 2025 | 1000 |
 France | Not Recruiting | 01 Sept 2025 | 280 |
 Germany | Not Recruiting | 01 Sept 2025 | 200 |
Sites & Investigators
Investigational Products
Details about the medicinal products being studied in this clinical trial.
| Product Name | Role in Trial | Formulation | Administration | Max Daily Dose | Treatment Duration | EU MP Number |
|---|---|---|---|---|---|---|
CHLORURE DE SODIUM 0,9 % B. BRAUN, solution pour perfusion | Placebo | SOLUTION POUR PERFUSION | INJECTION | 0.8 | 1 | PRD8723504 |
OVX836 | Test | SOLUTION FOR INJECTION/INFUSION/INHALATION | INJECTION | 480 | 1 | PRD6199567 |