TGA approves Novavax vaccine, oral treatments for COVID-19

After much anticipation and delay, the Therapeutic Goods Administration (TGA) has finally granted provisional approval to Biocelect (on behalf of Novavax) for its COVID-19 vaccine, NUVAXOVID. This is the first protein COVID-19 vaccine to receive regulatory approval in Australia, having previously received conditional marketing authorisation by the European Medicines Agency and an emergency use listing from the World Health Organization (WHO).

Protein vaccines use a non-infectious component found on the surface of the coronavirus and are manufactured in cells in a laboratory. After vaccination, immune cells recognise the vaccine protein as foreign and launch an immune response against it. Protein vaccine technology is more traditional than the mRNA (Pfizer and Moderna) and viral vector (AstraZeneca) platforms used for other COVID-19 vaccines, and for that reason has been viewed by some vaccine-hesitant people as more trustworthy.

Paul Griffin served as principal investigator on the vaccine’s first clinical trial, which saw it administered to healthy Australian volunteers in May 2020. “Following the success of this study,” he said, “this vaccine was then subsequently studied intensively in large clinical trials around the world that demonstrated an efficacy rate above 90% and a favourable safety profile.

“Another significant favourable property of this vaccine is that it can be stored for nine months at standard refrigeration temperatures.”

The protein subunit vaccine will be included in the Australian Register of Therapeutic Goods (ARTG) for active immunisation to prevent COVID-19 in individuals 18 years of age and older. It is recommended that the vaccine is given in two doses administered three weeks apart. Studies for use of NUVAXOVID as a booster dose and in paediatric patients are ongoing, so the vaccine does not have regulatory approval for these purposes at this stage.

The Australian Government announced an advance purchase agreement for 51 million doses of Novavax’s COVID-19 vaccine in January 2021. The first shipment to Australia is expected in the coming month, with the Australian Technical Advisory Group on Immunisation (ATAGI) set to have final say on how the vaccine will be distributed.

The TGA has also provisionally approved the first two oral treatments for COVID-19 in Australia: PAXLOVID (nirmatrelvir + ritonavir), from Pfizer Australia, and LAGEVRIO (molnupiravir), from Merck Sharp & Dohme (Australia). The products have been granted provisional approval for the treatment of adults with COVID-19 who do not require initiation of oxygen and who are at increased risk of progression to hospitalisation or death, which may be due to health conditions including obesity, diabetes or heart disease as well as older age. They are not intended as a substitute for vaccination.

Molnupiravir (LAGEVRIO) works by inhibiting replication of the SARS-CoV-2 virus. With PAXLOVID, the nirmatrelvir component blocks the activity of a protease enzyme that the coronavirus needs in order to replicate; nirmatrelvir is administered in combination with low-dose ritonavir to maintain plasma levels of nirmatrelvir for the duration of the treatment. The drugs should be administered as soon as possible after diagnosis of COVID-19 and within five days of the start of symptoms, and taken twice a day for five days.

Both PAXLOVID and LAGEVRIO have received conditional marketing authorisation from the UK Medicines and Healthcare products Regulatory Agency and emergency use authorisation from the US FDA; PAXLOVID was also authorised by Health Canada earlier this week. They will be available by prescription and are not recommended in several scenarios, including for pregnant or breastfeeding women. PAXLOVID must also not be used with a number of other common medicines, or by patients with severely reduced kidney or liver function.

The Australian Government has secured access to 500,000 treatment courses of PAXLOVID and 300,000 courses of LAGEVRIO for supply during 2022, with the first deliveries of both medicines anticipated in the coming weeks.

Image courtesy of Novavax

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