COVID-19Phase 3NCT05279456
A Phase 3b/4 Randomised Trial of 3 Doses of Protein-based Covid-19 Vaccine (SpikoGen)
A Phase 3 study testing Advax-CpG55.2 adjuvanted recombinant spike protein in people with COVID-19, run by Vaxine Pty Ltd at 1 site in Australia.
Trial 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. Read more about this study
- Who is it for?
- Ages 18 years and olderHealthy volunteers can take part
- Conditions the study is for
- COVID-19
- What is being tested?
- Advax-CpG55.2 adjuvanted recombinant spike protein
- Type of treatment
- Vaccines, Injection or infusion
- Could I receive a placebo?
- No, everyone receives an active treatment
- How many people
- 39 participants
- Where
- 1 siteAustralia
- Study dates
- 15 Aug 2022to 31 Dec 2023
- Phase
- Phase 3
- Are there results?
- None posted in the registry
Key requirements
Who can take part, as listed by the sponsor. Only the study team can confirm whether you are eligible, so take this list to your doctor.
- Ages 18 years and older
- All sexes
- Healthy volunteers accepted
- Adult, Older adult
Who may be able to join
- 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
Who cannot join
- 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.
Trial locations and contacts
1 site in 1 country.
About this study
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.
Read the 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.
- Conditions
- COVID-19
- Being tested
- Advax-CpG55.2 adjuvanted recombinant spike protein
- Keywords
- sars-cov-2, coronavirus, vaccine, adjuvant, Advax, Spikogen, Covax-19
- Medical subject headings
- COVID-19, Coronavirus Infections
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
Advax-CpG55.2 adjuvanted recombinant spike proteinBiological
Also called Spikogen vaccine
recombinant SARS-CoV-2 spike protein formulated with Advax-CpG55.2 adjuvant
| Study group | Role | What they receive |
|---|---|---|
| Spikogen vaccine - accelerated arm | Experimental | Spikogen vaccine 25 micrograms by intramuscular injection on study months 0, 1 and 2 Receives: Biological: Advax-CpG55.2 adjuvanted recombinant spike protein |
| Spikogen vaccine - standard arm | Experimental | Spikogen vaccine 25 micrograms by intramuscular injection on study months 0, 1 and 4 Receives: Biological: Advax-CpG55.2 adjuvanted recombinant spike protein |
What is being measured
The primary outcome is the main question the study is designed to answer.
First dose Seroconversion
Proportion of subjects in each group stratified by baseline antibody positivity seroconverting to spike protein antibody positivity
Measured: 2-4 weeks post first immunisation
Second dose Seroconversion
Proportion of subjects in each group stratified by baseline antibody positivity seroconverting to spike protein antibody positivity
Measured: 2-4 weeks post second immunisation
Third Dose Seroconversion
Proportion of subjects in each group stratified by baseline antibody positivity seroconverting to spike protein antibody positivity
Measured: 2-4 weeks post third immunisation
Final Seroconversion
Proportion of subjects in each group stratified by baseline antibody positivity seroconverting to spike protein antibody positivity
Measured: through study completion, an average of 7 months
First Dose GMT
Spike protein antibody Geometric Mean Titers (GMT) in each group stratified by baseline antibody positivity
Measured: 2-4 weeks post first immunisation
Second Dose GMT
Spike protein antibody Geometric Mean Titers (GMT) in each group stratified by baseline antibody positivity
Measured: 2-4 weeks post second immunisation
Third Dose GMT
Spike protein antibody Geometric Mean Titers (GMT)in each group stratified by baseline antibody positivity
Measured: 2-4 weeks post third immunisation
Final GMT
Spike protein antibody Geometric Mean Titers (GMT)in each group stratified by baseline antibody positivity
Measured: through study completion, an average of 7 months
First Dose Adverse events (AE)
AE occurring within 7 days of immunisation in each group stratified by baseline antibody positivity
Measured: 7 days post first immunisation
Second Dose Adverse events (AE)
AE occurring within 7 days of immunisation in each group stratified by baseline antibody positivity
Measured: 7 days post second immunisation
Third Dose Adverse events (AE)
AE occurring within 7 days of immunisation in each group stratified by baseline antibody positivity
Measured: 7 days post third immunisation
Serious adverse events (SAE)
Number of Serious adverse events (SAE) occurring within study period in each group stratified by baseline antibody positivity
Measured: through study completion, an average of 7 months
Secondary outcomes (6)
First dose Vaccine efficacy
Proportion of Covid-19 infections in trial participants in each group stratified by baseline antibody positivity
Measured: From 2 weeks post-first dose to 2 weeks after second dose
Second dose Vaccine efficacy
Proportion of Covid-19 infections in trial participants in each group stratified by baseline antibody positivity
Measured: From 2 weeks post-second dose to 2 weeks after third dose
Third dose Vaccine efficacy
Proportion of Covid-19 infections in trial participants in each group stratified by baseline antibody positivity
Measured: From 2 weeks post-third dose through study completion, an average of 7 months
Total Covid-19 infections
Proportion of breakthrough Covid-19 infections in trial participants in each group stratified by baseline antibody positivity
Measured: From first vaccine dose through study completion, an average of 7 months
Seroconversion against variants of concern
Serum spike protein antibody seroconversion rates against each SARS-CoV-2 variant of concern in trial participants in each group stratified by baseline antibody positivity
Measured: 2-4 weeks post first, second and third immunisation and at study completion
GMT against variants of concern
Geometric mean serum spike protein antibodies against SARS-CoV-2 variants in trial participants in each group stratified by baseline antibody positivity
Measured: 2-4 weeks post first, second and third immunisation and at study completion
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted15 Mar 2022
- Study start15 Aug 2022
- Primary completion31 Dec 2023
- Study completion31 Dec 2023
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Publications (1)Papers the sponsor has linked to this study.
- Other trials for COVID-19Studies of the same condition, open and under way.
- What the trial phases meanHow a treatment moves from first tests in people to approval.
More details
For doctors and researchers: how the study is designed, who runs it, and its registry IDs.
Study design
- Study type
- Interventional
- Phase
- Phase 3
- Primary purpose
- Prevention
- Allocation
- Randomised
- Intervention model
- Parallel groups
- Model description
- Subjects will be stratified for analysis by age, sex and seropositivity at time of study entry
- Masking
- None (open label)
- Enrolment
- 39 participants (actual)
Sponsor and investigators
- Lead sponsor
- Vaxine Pty Ltd
- Sponsor type
- Industry (pharma, biotech, devices)
- Collaborators
- Australian Respiratory and Sleep Medicine Institute
- Responsible party
- Sponsor
- Investigators
- Dimitar Sajkov, MBBS, Study director, ARASMI
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT05279456
- Sponsor's protocol ID
- AUST-C19-P3/4
- Status last verified
- Sep 2025
- First submitted
- 7 Mar 2022
- Last updated
- 17 Sep 2025
- Results posted
- No
- Data monitoring committee
- No
- FDA-regulated drug
- No
- FDA-regulated device
- No
- Individual data sharing
- No: There is no current plan to share IPD with other researchers, but requests for data access will be considered on a case by case basis
Publications
Li L, Honda-Okubo Y, Huang Y, Jang H, Carlock MA, Baldwin J, Piplani S, Bebin-Blackwell AG, Forgacs D, Sakamoto K, Stella A, Turville S, Chataway T, Colella A, Triccas J, Ross TM, Petrovsky N. Immunisation of ferrets and mice with recombinant SARS-CoV-2 spike protein formulated with Advax-SM adjuvant protects against COVID-19 infection. Vaccine. 2021 Sep 24;39(40):5940-5953. doi: 10.1016/j.vaccine.2021.07.087. Epub 2021 Aug 3.
PubMed 34420786
Study at a glance
From the registry record, last updated by the sponsor on 17 Sep 2025. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- A Phase 3b/4 Randomised Trial of 3 Doses of Protein-based Covid-19 Vaccine (SpikoGen)
- ClinicalTrials.gov ID
- NCT05279456
- Acronym / sponsor ID
- AUST-C19-P3/4
- Conditions
- COVID-19
- Keywords
- sars-cov-2, coronavirus, vaccine, adjuvant, Advax, Spikogen, Covax-19
- Phase
- Phase 3
- Study type
- Interventional
- Recruitment status
- Completed
- Enrolment
- 39 participants (actual)
- Lead sponsor
- Vaxine Pty LtdIndustry (pharma, biotech, devices)
- Collaborators
- Australian Respiratory and Sleep Medicine Institute
- Study start
- 15 Aug 2022 (actual)
- Primary completion
- 31 Dec 2023 (actual)
- Study completion
- 31 Dec 2023 (actual)
- First posted
- 15 Mar 2022 (actual)
- Results
- Not posted in the source record
Clinical summary
The research question as the sponsor registered it. This describes what the study plans to test, not what it found.
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.
Study design
- Primary purpose
- Prevention
- Allocation
- Randomised
- Intervention model
- Parallel groups
- Masking
- None (open label)
- Number of arms
- 2
- Model description
- Subjects will be stratified for analysis by age, sex and seropositivity at time of study entry
| Arm | Type | Receives |
|---|---|---|
| Spikogen vaccine - accelerated arm | Experimental | Biological: Advax-CpG55.2 adjuvanted recombinant spike proteinSpikogen vaccine 25 micrograms by intramuscular injection on study months 0, 1 and 2 |
| Spikogen vaccine - standard arm | Experimental | Biological: Advax-CpG55.2 adjuvanted recombinant spike proteinSpikogen vaccine 25 micrograms by intramuscular injection on study months 0, 1 and 4 |
Who may qualify
- Ages
- 18 years and older
- Sex
- All
- Healthy volunteers
- Accepted
- Age groups
- Adult, Older adult
Key inclusion criteria (4 listed)
- 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
Key exclusion criteria (5 listed)
- 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.
Eligibility is decided by the study team after screening; this overview does not establish that a patient qualifies. Full inclusion and exclusion criteria.
Interventions
| Intervention | Type | Arms |
|---|---|---|
| Advax-CpG55.2 adjuvanted recombinant spike proteinAlso: Spikogen vaccinerecombinant SARS-CoV-2 spike protein formulated with Advax-CpG55.2 adjuvant | Biological | Spikogen vaccine - accelerated arm, Spikogen vaccine - standard arm |
Primary outcome
First dose Seroconversion
Time frame: 2-4 weeks post first immunisation
Proportion of subjects in each group stratified by baseline antibody positivity seroconverting to spike protein antibody positivity
Second dose Seroconversion
Time frame: 2-4 weeks post second immunisation
Proportion of subjects in each group stratified by baseline antibody positivity seroconverting to spike protein antibody positivity
Third Dose Seroconversion
Time frame: 2-4 weeks post third immunisation
Proportion of subjects in each group stratified by baseline antibody positivity seroconverting to spike protein antibody positivity
Final Seroconversion
Time frame: through study completion, an average of 7 months
Proportion of subjects in each group stratified by baseline antibody positivity seroconverting to spike protein antibody positivity
First Dose GMT
Time frame: 2-4 weeks post first immunisation
Spike protein antibody Geometric Mean Titers (GMT) in each group stratified by baseline antibody positivity
Second Dose GMT
Time frame: 2-4 weeks post second immunisation
Spike protein antibody Geometric Mean Titers (GMT) in each group stratified by baseline antibody positivity
Third Dose GMT
Time frame: 2-4 weeks post third immunisation
Spike protein antibody Geometric Mean Titers (GMT)in each group stratified by baseline antibody positivity
Final GMT
Time frame: through study completion, an average of 7 months
Spike protein antibody Geometric Mean Titers (GMT)in each group stratified by baseline antibody positivity
First Dose Adverse events (AE)
Time frame: 7 days post first immunisation
AE occurring within 7 days of immunisation in each group stratified by baseline antibody positivity
Second Dose Adverse events (AE)
Time frame: 7 days post second immunisation
AE occurring within 7 days of immunisation in each group stratified by baseline antibody positivity
Third Dose Adverse events (AE)
Time frame: 7 days post third immunisation
AE occurring within 7 days of immunisation in each group stratified by baseline antibody positivity
Serious adverse events (SAE)
Time frame: through study completion, an average of 7 months
Number of Serious adverse events (SAE) occurring within study period in each group stratified by baseline antibody positivity
6 secondary outcomes
First dose Vaccine efficacy
Time frame: From 2 weeks post-first dose to 2 weeks after second dose
Second dose Vaccine efficacy
Time frame: From 2 weeks post-second dose to 2 weeks after third dose
Third dose Vaccine efficacy
Time frame: From 2 weeks post-third dose through study completion, an average of 7 months
Total Covid-19 infections
Time frame: From first vaccine dose through study completion, an average of 7 months
Seroconversion against variants of concern
Time frame: 2-4 weeks post first, second and third immunisation and at study completion
GMT against variants of concern
Time frame: 2-4 weeks post first, second and third immunisation and at study completion
Results and safety
The study is completed, but results are not available in the source record. That does not mean the treatment did or did not work.
Research links
- Official record on ClinicalTrials.govLast updated by the sponsor 17 Sep 2025.
- Background: PubMed 34420786Li L, Honda-Okubo Y, Huang Y, Jang H, Carlock MA, Baldwin J, Piplani S, Bebin-Blackwell AG, Forgacs D, Sakamoto K, Stella A, Turville S, Chataway T, Colella A, Triccas J, Ross TM, Petrovsky N. Immunisation of ferrets and mice with recombinant SARS-CoV-2 spike protein formulated with Advax-SM adjuvant protects against COVID-19 infection. Vaccine. 2021 Sep 24;39(40):5940-5953. doi: 10.1016/j.vaccine.2021.07.087. Epub 2021 Aug 3.
- Link to company websiteLink provided by the sponsor.
- Individual participant dataSharing planned: No. There is no current plan to share IPD with other researchers, but requests for data access will be considered on a case by case basis
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Referral and contact
AzTrials does not enrol participants or take referrals. Contact the study team or a site listed below; they decide who can take part. This study is not recruiting at the moment.
Dimitar Sajkov, MBBS study director
ARASMI
1 site in 1 country: see every site and its status.
Questions about this trial
What is this clinical trial studying?
A Phase 3 study testing Advax-CpG55.2 adjuvanted recombinant spike protein in people with COVID-19, run by Vaxine Pty Ltd at 1 site in Australia.
The full registered description is in the About this study section and the official record.
Who may be eligible to take part?
The sponsor lists 4 inclusion and 5 exclusion criteria. Eligibility is decided by the study team after screening, so read the full criteria and contact a listed site.
Is this clinical trial currently recruiting?
The record says: finished, as of the sponsor's last update on 17 Sep 2025. Status can change between updates, so confirm with the study contact before making plans.
Where is the study taking place?
The record lists 1 site in Australia. Whether a site is taking part right now should be confirmed with that site. See every site.
What are the possible benefits and risks?
They depend on the study and the treatment, and no study can promise a benefit. The study team explains the known risks during informed consent, before anyone joins; the record itself does not list them.
What does this phase mean?
Phase 3 studies compare the treatment with the current standard treatment or a placebo in a large group, to confirm how well it works and watch for side effects.
Not every study follows the same path, and some studies (observational studies, device studies) have no phase.
Are results available for this study?
The study is completed, but results are not available in the source record. That does not mean the treatment did or did not work.
How can a doctor refer a patient or contact the research team?
The record lists no contact. The official record names the sponsor, who can be asked directly. AzTrials does not enrol participants or take referrals.
What does the primary outcome measure?
First dose Seroconversion (time frame: 2-4 weeks post first immunisation). The study lists 12 primary outcomes in all. It is what the study was designed to measure, not a finding.
Where can I read the original study information?
On the ClinicalTrials.gov record for NCT05279456, which also lists 1 linked publication.
Does a listing mean the treatment is approved or proven to work?
No. A listing means the study is registered. It does not show that the treatment is safe, works, or is approved by a regulator.
How often is this information updated?
AzTrials copies changed records from ClinicalTrials.gov every night and reloads the whole registry every week. The sponsor last updated this record on 17 Sep 2025.