RecruitingPhase 1ACTRN12626000259347

A Phase 1a/b Randomized, Double-Blind, Placebo-Controlled, Dose Escalation Study with an Open-Label Active-Controlled Phase, to Evaluate the Safety and Immunogenicity of Centi-Flu 01 in Healthy Adults 18 Years of Age and Older

Sponsor

Centivax, Inc.

Enrollment

180 participants

Start Date

Feb 5, 2026

Study Type

Interventional

Conditions

Influenza

Summary

Eligibility

Sex: Both males and femalesMin Age: 18 Yearss

Inclusion Criteria18

Potential participants who meet all of the following criteria are eligible for participation in the study:
Must have given written informed consent before any study-related activities are performed and must be able to understand the full nature and purpose of the study, including possible risks and adverse effects.
Adult, male or female, aged 18 years or older, with a body mass index (BMI) of between 18.0 (inclusive) to less than or equal to 35.0 at screening.
Medically healthy (in the opinion of the PI or delegate), as determined by satisfactory medical history, physical examination, vital signs, ECG assessments, laboratory evaluation (troponin, clinical chemistry, hematology and urinalysis) and clinical judgment of the Investigator (laboratory evaluation applicable to screening only). Participants with stable, chronic underlying illnesses such as psychiatric/psychological disorders, hypertension, diabetes, ischemic heart disease or hypothyroidism (or other conditions as per investigator’s discretion) may be enrolled provided their signs and symptoms are controlled. If on regular prescription medication, the medication dose must have been stable for at least 3 months prior to Screening.
Available for the required follow-up period and scheduled clinic visits and willing and able to comply with study procedures including laboratory tests and lifestyle considerations.
For participants 65 years of age and older, receipt of licensed influenza vaccination for the 2024-2025 Southern Hemisphere Season 120 days or longer before study intervention administration.
Women of childbearing potential must have a negative pregnancy test at screening, and on Day 1, prior to dosing3. A positive urine pregnancy test will be confirmed by a serum pregnancy test.
Females:
a. Must be of nonchildbearing potential, i.e., surgically sterilized (hysterectomy, bilateral salpingectomy, bilateral oophorectomy) at least 6 weeks before the screening visit or postmenopausal (where postmenopausal is defined as no menses for 12 months without an alternative medical cause and a follicle-stimulating hormone [FSH] level consistent with postmenopausal status, per local laboratory guidelines), or
b. If of childbearing potential, must:
i. Have a negative pregnancy test at the screening visit and on Day 1, prior to dose administration.
ii. Agree not to attempt to become pregnant or donate ova from signing the ICF until at least 3 months following the last dose of study drug.
iii. Agree to use adequate contraception (defined as use of a highly effective method of contraception from one month prior to screening until at least 3 months after the last dose of study drug, if not exclusively in a same-sex relationship or abstinent as a committed lifestyle.
Males:
a. Must agree not to donate sperm from signing the ICF until at least 3 months days after the last dose of study drug.
b. If engaging in sexual intercourse with a female partner who could become pregnant, must agree to use adequate contraception (defined as use of a highly effective method of contraception from signing the ICF until at least 3 months after the last dose of study drug.
Have suitable venous access for blood sampling.
Must agree to refrain from blood donation during the study.

Exclusion Criteria29

Potential participants will be excluded from the study if they meet any of the following criteria:
Clinically significant (CS) abnormalities on physical examination that, in the PI’s opinion, would preclude full evaluation of potential AEs including permanent body art (e.g., tattoo) that, in the opinion of the Investigator or appropriately delegated Sub-investigator, would obstruct the ability to observe local reactions at the injection site.
History of severe adverse reaction associated with any vaccine and/or severe allergic reaction (e.g., anaphylaxis) to any component of the study intervention(s).
History of myocarditis.
Immunocompromised individuals with known or suspected immunodeficiency acquired or congenital, or autoimmune conditions as determined by history and/or physical examination.
Bleeding diathesis or condition associated with prolonged bleeding.
Receipt of chronic systemic treatment with known immunosuppressant medications (including cytotoxic agents or systemic corticosteroids), radiotherapy, or other immune-modifying drugs within 60 days prior to screening through conclusion of the study with the exclusion of 10 mg of prednisone or less transiently.
Receipt of blood/plasma products, immunoglobulin, or monoclonal antibodies, from 120 days prior to first dose administration on Day 1, or planned receipt throughout the study.
Immunization with any investigational or licensed influenza vaccine within 4 months before study intervention administration or for the duration of the study unless medically indicated.
Investigator site staff directly involved in the conduct of the study and their family members, site staff otherwise supervised by the investigator, and Sponsor and Sponsor delegate employees directly involved in the conduct of the study and their family members.
Women who are pregnant or planning to become pregnant during the study period plus 3 months beyond the last received dose, and currently nursing women. or women planning to breastfeed at any point during the study.
Participation in research involving another investigational product (defined as receipt of investigational product or exposure to invasive investigational device) within 30 days prior to screening visit or any time through the last study safety visit.
Known history of hepatitis C virus, hepatitis B virus or human immunodeficiency virus-1/2 infections, per participant report, or positive test for hepatitis B, hepatitis C, or HIV infection at Screening.
Any known active systemic infection.
Receipt of systemic anti-bacterial medications (i.e., for bronchitis, sinusitis, upper respiratory tract infection) or anti-viral medications (i.e., influenza, herpes) within 14 days of screening.
Diagnosis of COVID-19, preferably confirmed by positive severe acute respiratory syndrome-coronavirus 2 (SARS-CoV-2) nasal, nasopharyngeal, or oropharyngeal swab by locally authorized Antigen, Nucleic Acid Amplification Test, or reverse transcription PCR test within 2 weeks of the screening visit.
History of moderate or severe COVID-19 requiring hospitalization in the 60 days prior to Day 1.
Receipt of any live attenuated vaccine within 28 days prior to first dose of the study drug on Day 1, or receipt of any non-live vaccine within 14 days prior to the first dose of study drug on Day 1.
Any known active infection or a known history of documented influenza infection within the past 90 days.
Have known active or recently active (12 months) neoplastic disease or a history of any hematologic malignancy (excluding non-melanoma, treated skin cancers).
History of anaphylaxis or other significant allergies, including allergy to egg proteins (egg or egg products) or chicken proteins.
History of Guillain-Barré Syndrome.
History of risk factors for torsade de pointes (including a family history of long QT syndrome or sudden cardiac death) or a known arrythmia.
History of any significant myocardial, hematologic, coagulopathic or neurologic reaction to an RNA vaccine.
Donation of blood within 30 days prior to first dose of study drug, or loss of whole blood of more than 500 mL within 30 days prior to first dose of study drug, or receipt of a blood transfusion within 3 months of the first dose of study vaccine.
Donation of plasma within 21 days prior to the first dose of study drug.
Positive alcohol or drugs of abuse test at the screening visit and/or prior to dose administration on Day 1.
Excessive use of alcohol with a guideline of regular consumption of more than 10 standard alcoholic drinks/week and/or more than 4 standard alcoholic drinks on any one day, where 1 standard drink is 10 g of pure alcohol and is equivalent to 285 mL beer, 100 mL wine, or 30 mL spirit.
Any other condition or prior therapy that in the opinion of the PI (or delegate) would make the volunteer unsuitable for this study.

Interested in this trial?

Get notified about updates and connect with the research team.

Interventions

This is a double-blind, placebo-controlled, dose-escalating study conducted in healthy adult volunteers. The study will be conducted in 2 parts, with each part having a double-blind period and an open-label period. The phase 1a study will evaluate the safety and immunogenicity of Centi-Flu 01 in healthy adults aged 18 to 64 (Cohorts 1 and 2), and healthy adults egual to or greater than age 65 (Cohorts 3 and 4). In this part of the study, 6 different dosing regimens of Centi-Flu 01 will be evaluated in a double-blind manner. Up to 180 participants will be enrolled across a total of 4 cohorts, with each cohort consisting of 3 groups. Sentinel dosing will also be utilized in each cohort. Dose and age escalation will be based on the principle that to proceed with the lowest doses in older adults and to proceed with higher doses in the younger adults, preliminary safety of the lowest doses in younger adults will first be established. Each group will enroll up to 15 participants with 12 participants randomised to receive Centi-Flu 01 and 3 participants randomised to receive placebo. Participants will receive a single intramuscular (IM) dose in the upper deltoid region of the arm of Centi-Flu 01 or placebo (according to their randomisation for the double-blind portion of the study) on Days 1 and 56, at the following dose levels: Cohort 1: Group 1) - First dose - 10µg administered as a single IM injection on Day 1, Second dose - 10µg administered as a single IM injection on Day 56 Cohort 1: Group 2) - First dose - 30µg administered as a single IM injection on Day 1, Second dose - Placebo administered as a single IM injection on Day 56 Cohort 1: Group 3) - First dose - 30µg administered as a single IM injection on Day 1, Second dose - 30µg administered as a single IM injection on Day 56 Cohort 2: Group 4) - First dose - 60µg administered as a single IM injection on Day 1, Second dose - Placebo administered as a single IM injection on Day 56 Cohort 2: Group 5) - First dose - 60µg administered as a single IM injection on Day 1, Second dose - 60µg administered as a single IM injection on Day 56 Cohort 2: Group 5) - First dose - 90µg administered as a single IM injection on Day 1, Second dose - Placebo administered as a single IM injection on Day 56 Cohort 3: Group 7) - First dose - 10µg administered as a single IM injection on Day 1, Second dose - 10µg administered as a single IM injection on Day 56 Cohort 3: Group 8) - First dose - 30µg administered as a single IM injection on Day 1, Second dose - Placebo administered as a single IM injection on Day 56 Cohort 3: Group 9) - First dose - 30µg administered as a single IM injection on Day 1, Second dose - 30µg administered as a single IM injection on Day 56 Cohort 4: Group 10) - First dose - 60µg administered as a single IM injection on Day 1, Second dose - Placebo administered as a single IM injection on Day 56 Cohort 5: Group 11) - First dose - 60µg administered as a single IM injection on Day 1, Second dose - 60µg administered as a single IM injection on Day 56 Cohort 6: Group 12) - First dose - 90µg administered as a single IM injection on Day 1, Second dose - Placebo administered as a single IM injection on Day 56 Following completion of Day 64 assessments, the study will be unblinded, and those who were randomised to receive placebo will receive a seasonal vaccination during the next influenza seasonal vaccination timeframe. Adaptive design elements of the study will be used to determine whether participants will receive a booster dose of Centi-Flu 01 (if they were randomised to Centi-Flu 01) or the seasonal vaccination (if they were randomised to placebo) 1 year following their initial vaccination. At 1 year following the initial immunisation with Centi-Flu 01, an adaptive design decision based on immunogenicity data, including sera collected at Month 11 (Day 335), will determine whether a booster dose of Centi-Flu 01 will be administered. Therefore, there may or may not be a third immunisation. Different groups may differ in this regard depending on the durability and magnitude of their immune responses to the priming regimen, age cohort, dose level received, and emerging hemagglutination inhibition (HAI) data reviewed as part of the adaptive design. Participants who initially received Centi-Flu 01 as a first dose and then received placebo as a second dose (ie those receiving 30 or 60µg Centi-Flu 01 mRNA) will not be given a commercial vaccine unless it is determined by serology that they did not make an adequate HAI response to the regimen. In that case when the serologic data is available they will receive a commercial vaccine. Strategies to assess and monitor adherence to the intervention include observation and recording of the vaccine administration in appropriate drug accountability records and measurement of the serologic HAI responses to the vaccine compared to baseline.