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

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.