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A Phase 3b/4 Randomised Trial of 3 Doses of Protein-based Covid-19 Vaccine (SpikoGen)

A Phase 3b/4 Randomised Trial of 3 Doses of Protein-based Covid-19 Vaccine (SpikoGen)

Status
Completed
Phases
Phase 3
Study type
Interventional
Source
ClinicalTrials.gov
Registry ID
NCT05279456
Enrollment
39
Registered
2022-03-15
Start date
2022-08-15
Completion date
2023-12-31
Last updated
2025-09-17

For informational purposes only — not medical advice. Sourced from public registries and may not reflect the latest updates. Terms

Conditions

COVID-19

Keywords

sars-cov-2, coronavirus, vaccine, adjuvant, Advax, Spikogen, Covax-19

Brief summary

This study will determine the immunogenicity of Spikogen in vaccine naïve individuals. Spikogen will be administered as two doses 1 month apart with a third booster dose either 1 or 3 months after the second dose. This study will provide key data on SARS-CoV-2 antibody responses.

Detailed description

The SARS-CoV-2 outbreak has caused millions of deaths globally. It has a particularly high mortality rate in elderly people and those with chronic disease where mortality rates can be as high as 20-30%. SARS-COV-2 vaccines remain a key priority to help fight the current pandemic. COVID-19 vaccines prevent symptomatic infection and may help reduce virus transmission. Spikogen® vaccine, also known as Covax-19™ in Australia, is an adjuvanted recombinant protein Covid-19 vaccine has recently been approved by the Iranian FDA for emergency use in Iran in adults as a primary vaccine course and booster dose, after meeting its primary efficacy endpoint in a Phase 3 trial in 16,876 participants randomised 3:1 to receive Spikogen vaccine or saline placebo via two intramuscular doses 3 weeks apart where Spikogen vaccine demonstrated significant protection against serious infection with the delta variant. Approximately 5-10% of the broader Australian population and an even higher proportion of the indigenous populations remains unvaccinated despite current availability of these vaccines. One reason is that some people have medical contraindications to the current vaccines, such as serious allergies to the vaccine components such as polyethyleneglycol (PEG) in the mRNA vaccines. Spikogen vaccine is made using a recombinant protein approach with the SARS-CoV-2 spike protein synthesized in an insect cell line grown in broth. Insect cell expression of recombinant protein is a well-established vaccine manufacturing approach. Spikogen vaccine also contains a unique Australian developed adjuvant called Advax-CpG55.2, which is added to the spike protein to make the vaccine more effective. AdvaxCpG55.2 has two components, one a natural plant sugar called inulin, and the second a short synthetic oligonucleotide polymer, known as CpG55.2 oligonucleotide. Spikogen vaccine is designed to protect against SARS-CoV-2 infection. It has been shown to be effective against infection in hamster, ferret and monkey SARS-CoV-2 infection models. This study will determine the immunogenicity of Spikogen in vaccine-naïve individuals. Spikogen will be administered as two doses 31 month apart with a third booster dose given either 1 or 3 months after the second dose.

Interventions

BIOLOGICALAdvax-CpG55.2 adjuvanted recombinant spike protein

recombinant SARS-CoV-2 spike protein formulated with Advax-CpG55.2 adjuvant

Sponsors

Australian Respiratory and Sleep Medicine Institute
CollaboratorOTHER
Vaxine Pty Ltd
Lead SponsorINDUSTRY

Study design

Allocation
RANDOMIZED
Intervention model
PARALLEL
Primary purpose
PREVENTION
Masking
NONE

Intervention model description

Subjects will be stratified for analysis by age, sex and seropositivity at time of study entry

Eligibility

Sex/Gender
ALL
Age
18 Years to No maximum
Healthy volunteers
Yes

Inclusion criteria

* Able to provide written informed consent * Males or females\* 18 years of age or older * Understand and are likely to comply with planned study procedures and be available for all study visits. * Have not previously had a Covid-19 vaccine and do not intend to have a non-study Covid-19 vaccine within the next 6 months

Exclusion criteria

* History of Covid-19 vaccination. * History of serious vaccine allergy. * Pregnancy1 * Have received an experimental agent within 30 days prior to the study vaccination or expect to receive another experimental agent during the trial reporting period. * Any medical, social or mental condition which, in the opinion of the investigator, would be detrimental to the subjects or the study.

Design outcomes

Primary

MeasureTime frameDescription
Serious adverse events (SAE)through study completion, an average of 7 monthsNumber of Serious adverse events (SAE) occurring within study period in each group stratified by baseline antibody positivity
First dose Seroconversion2-4 weeks post first immunisationProportion of subjects in each group stratified by baseline antibody positivity seroconverting to spike protein antibody positivity
Second dose Seroconversion2-4 weeks post second immunisationProportion of subjects in each group stratified by baseline antibody positivity seroconverting to spike protein antibody positivity
Third Dose Seroconversion2-4 weeks post third immunisationProportion of subjects in each group stratified by baseline antibody positivity seroconverting to spike protein antibody positivity
Final Seroconversionthrough study completion, an average of 7 monthsProportion of subjects in each group stratified by baseline antibody positivity seroconverting to spike protein antibody positivity
First Dose GMT2-4 weeks post first immunisationSpike protein antibody Geometric Mean Titers (GMT) in each group stratified by baseline antibody positivity
Second Dose GMT2-4 weeks post second immunisationSpike protein antibody Geometric Mean Titers (GMT) in each group stratified by baseline antibody positivity
Third Dose GMT2-4 weeks post third immunisationSpike protein antibody Geometric Mean Titers (GMT)in each group stratified by baseline antibody positivity
Final GMTthrough study completion, an average of 7 monthsSpike protein antibody Geometric Mean Titers (GMT)in each group stratified by baseline antibody positivity
First Dose Adverse events (AE)7 days post first immunisationAE occurring within 7 days of immunisation in each group stratified by baseline antibody positivity
Second Dose Adverse events (AE)7 days post second immunisationAE occurring within 7 days of immunisation in each group stratified by baseline antibody positivity
Third Dose Adverse events (AE)7 days post third immunisationAE occurring within 7 days of immunisation in each group stratified by baseline antibody positivity

Secondary

MeasureTime frameDescription
Third dose Vaccine efficacyFrom 2 weeks post-third dose through study completion, an average of 7 monthsProportion of Covid-19 infections in trial participants in each group stratified by baseline antibody positivity
Total Covid-19 infectionsFrom first vaccine dose through study completion, an average of 7 monthsProportion of breakthrough Covid-19 infections in trial participants in each group stratified by baseline antibody positivity
Seroconversion against variants of concern2-4 weeks post first, second and third immunisation and at study completionSerum spike protein antibody seroconversion rates against each SARS-CoV-2 variant of concern in trial participants in each group stratified by baseline antibody positivity
GMT against variants of concern2-4 weeks post first, second and third immunisation and at study completionGeometric mean serum spike protein antibodies against SARS-CoV-2 variants in trial participants in each group stratified by baseline antibody positivity
First dose Vaccine efficacyFrom 2 weeks post-first dose to 2 weeks after second doseProportion of Covid-19 infections in trial participants in each group stratified by baseline antibody positivity
Second dose Vaccine efficacyFrom 2 weeks post-second dose to 2 weeks after third doseProportion of Covid-19 infections in trial participants in each group stratified by baseline antibody positivity

Other

MeasureTime frameDescription
Antibody kinetics2-4 weeks post first, second and third immunisation and at study completionrate of change in peak to trough serum spike protein antibody levels over time in each group stratified by baseline antibody positivity
Age effects on antibody levels2-4 weeks post first, second and third immunisation and at study completionGeometric Mean Titers of spike protein antibodies in participants by age and gender
immune-deficiency effects on seroconversion2-4 weeks post first, second and third immunisation and at study completionProportion of subjects seroconverting to spike protein antibodies in participants with or without immune-deficiency
immune-deficiency effects on antibody levels2-4 weeks post first, second and third immunisation and at study completionGeometric Mean Titers (GMT) of spike protein antibodies in participants with or without immune-deficiency
Age effects on seroconversion2-4 weeks post first, second and third immunisation and at study completionProprotion seroconverting to spike protein antibodies analysed by age and gender

Countries

Australia

Outcome results

None listed

Source: ClinicalTrials.gov · Data processed: Feb 4, 2026